Akinetic Mutism

Significance of Beta-Blocker in Patients with Hypertensive Left Ventricular Hypertrophy and Myocardial Ischemia

Background: Arterial Hypertension (HTN) is a key risk factor for left ventricular hypertrophy (LVH) and a cause of ischemic heart disease (IHD). The association between myocardial ischemia and HTN LVH is strong because myocardial ischemia can occur in HTN LVH even in the absence of significant stenoses of epicardial coronary arteries.

Objective: To analyze pathophysiological characteristics/co-morbidities precipitating myocardial ischemia in patients with HTN LVH and provide a rationale for recommending beta-blockers (BBs) to prevent/treat ischemia in LVH.

Methods: We searched PubMed, SCOPUS, PubMed, Elsevier, Springer Verlag, and Google Scholar for review articles and guidelines on hypertension from 01/01/2000 until 01/05/2022. The search was limited to publications written in English.

Results: HTN LVH worsens ischemia in coronary artery disease (CAD) patients. Even without obstructive CAD, several pathophysiological mechanisms in HTN LVH can lead to myocardial ischemia. In the same guidelines that recommend BBs for patients with HTN and CAD, we could not find a single recommendation for BBs in patients with HTN LVH but without proven CAD. There are several reasons for the proposal of using some BBs to control ischemia in patients with HTN and LVH (even in the absence of obstructive CAD).

Conclusion: Some BBs ought to be considered to prevent/treat ischemia in patients with HTN LVH (even in the absence of obstructive CAD). Furthermore, LVH and ischemic events are important causes of ventricular tachycardia, ventricular fibrillation, and sudden cardiac death; these events are another reason for recommending certain BBs for HTN LVH.

Baclofen-induced Encephalopathy in Patients with End-stage Kidney Disease – A Case Series

Introduction/Background: Baclofen is a centrally acting GABA B receptor agonist, widely used for the treatment of neurological diseases ranging from hiccups to multiple sclerosis. As the drug is renally excreted, intoxication can rapidly develop in those patients with a reduced glomerular filtration rate. A strong index of clinical suspicion is essential to correctly diagnose the condition.

Case Presentation: We report a case series of patients with advanced kidney disease and baclofen-induced encephalopathy that settled with discontinuation of the drug and hemodialysis sessions.

Conclusion: We report this cluster of patients with baclofen toxicity to highlight the common occurrence of neurotoxicity after its use in patients with end-stage renal disease and its resolution after cessation of the drug and hemodialysis sessions.

The Role of NF-κB in Myocardial Ischemia/Reperfusion Injury

Acute myocardial infarction (AMI) is a threat to human life and physical health worldwide. Timely reperfusion is very important to limit infarct size and protect ischemic myocardium. Unfortunately, it has also caused severer myocardial damage, which is called “myocardial ischemia/ reperfusion injury (MIRI)”. There is no effective clinical treatment for it. Over the past two decades, biological studies of NF-κB have improved the understanding of MIRI. Nuclear Factor-κB (NF-κB) is a major transcription factor associated with cardiovascular health and disease. It is involved in the release of pro-inflammatory factors and apoptosis of cardiomyocytes. Recent studies have shown that inhibition of NF-κB plays a protective role in acute hypoxia and reperfusion injury. Here we review the molecular regulation of NF-κB in MIRI, better understanding of NF-κB signaling mechanisms related to inflammation and crosstalk with endogenous small molecules. We hope this review will aid in improving therapeutic approaches to clinical diagnosing. This review provides evidence for the role of NF-κB in MIRI and supports its use as a therapeutic target.

Relationship between Augmentation Index and Wall Thickening Fraction during Hypotension in an Animal Model of Myocardial Ischemia-Reperfusion and Heart Failure

Aims: Non-invasive indices to evaluate left ventricular changes during ischemic heart failure are needed to quantify the myocardial impairment and the effectiveness of therapeutic manoeuvres. The aims of this work were to calculate the Wall Thickening Fraction (WTF) and the Augmentation Index (AIx) and to assess the relationship between WTF and AIx using data obtained from an animal model with heart failure followed by a myocardial ischemia stage and a reperfusion stage.

Methods: Nine Corriedale sheep that had been monitored for 10 minutes during a basal stage underwent 5-minute myocardial ischemia, followed by 60-minute reperfusion. Seven of them were subjected to an induced heart failure through an overdose of halothane, two of which were treated with intra-aortic counterpulsation during the reperfusion stage. The remaining two animals were monitored during their ischemia-reperfusion stage.

Results: Data obtained in the 5 animals suffering from heart failure followed by myocardial ischemia showed that: a) heart failure induction determined decrease in cardiac output, cardiac index and systolic and diastolic aortic pressure (AoP) with respect to their basal values (p<0.05), b) myocardial ischemia decreased the WTF compared with basal and induced heart failure values (p<0.05), c) during the reperfusion stage accompanied by induced heart failure, WTF increased with respect to values observed during the ischemia induction stage (p<0.05); nevertheless, basal values were not recovered after reperfusion (p<0.05). During this 60-minute stage, systolic and diastolic AoP values were lower (p<0.05) than those at the basal stage.

Conclusion: AIx and WTF values calculated from synchronically recorded values of aortic pressure and left ventricular wall thickness during the reperfusion stage in all animals (n = 9) showed a negative correlation (p<0.05). Analysed data provided evidence of a negative relationship between a left ventricular index of myocardial function and an arterial index obtained from AoP waves.

The Protective of Baicalin on Myocardial Ischemia-Reperfusion Injury

Background: The aim of this study was to explore the inhibitory effect of baicalin on myocardial apoptosis induced by Ischemia-Reperfusion (I/R).

Methods: Sprague Dawley rats' heart and myocardial cells I/R model were established in vivo and vitro, then 100 mg/kg and 10 μmol/l baicalin were administrated, respectively. The experiment was randomly divided into 4 groups (n=10): Control; I/R; IR+DMEM; and I/R+baicalin groups. Postoperation, the Left Ventricular (LV) End-Diastolic Pressure (LVEDP), the maximum velocity of LV contraction (dP/dtmax) and the maximum velocity of LV diastole (dP/dtmin) were recorded by the transthoracic echocardiography; the myocardial apoptosis percentage was analyzed by Annexin VFITC/ PI and TUNEL staining, and the apoptosis gene and protein were detected by RT-PCR and western blot. Furthermore, the protein expression of the calcium-sensing receptor (CaSR) and ERK1/2 phosphorylation were observed by western blot and Fura-2-acetoxymethyl ester. Moreover, primary rats’ cardiomyocytes were cultured and ERK1/2 specific inhibitor PD98059 was added to the culture medium. The cell survival rate, vitality and apoptosis were detected by MTT, lactate dehydrogenase (LDH) and TUNEL staining assay Kit, respectively.

Results: Our present study showed that baicalin significantly improved LV hemodynamic parameters and myocardial apoptosis in myocardial I/R injury rats. Furthermore, we found that baicalin could down-regulate the protein expression of CaSR, but up-regulate the protein expression of ERK1/2. Furthermore, when the cells were pretreated with ERK1/2 inhibitor PD98059, the cells survival rate significantly decreased, but LDH activity and apoptosis significantly increased. The results indicated that the effect of baicalin on myocardial I/R injury could be inhibited by ERK1/2 inhibitor.

Conclusion: In conclusion, our data suggests that baicalin attenuates I/R-induced myocardial injury maybe through the suppression of the CaSR/ERK1/2 signaling pathway.

The Advances on the Protective Effects of Ginsenosides on Myocardial Ischemia and Ischemia-Reperfusion Injury

Ginseng is a traditional medicine with a complex chemical composition, wide bioactivity and unique pharmacological action. Many studies have confirmed that ginsenosides are the active ingredients of ginseng, and ginsenosides have always been the focus of different researchers. With the development of modern separation and analysis technology, more than 150 kinds of ginsenosides have been isolated. The ginsenosides Rb1, Rb2, Rc, Rg1 and Re account for more than 80% of total ginsenosides, and other saponins, such as Rd, Rg3 and Rh2, which are minor constituents, accounting for only a small portion of the total amount. In recent years, ginsenosides have been found to possess strong pharmacological activities, such as antioxidation, clearing of oxygen free radicals, reducing calcium overload and anti-apoptosis. Ginsenosides play a protective role in ischemia-reperfusion injury. This paper reviews the protective effects of ginsenosides on myocardial ischemia and ischemiareperfusion injury.

Impaired Myocardial MIF/AMPK Activation Aggravates Myocardial Ischemia Reperfusion Injury in High-Fat Diet-Induced Obesity

Background: Obese patients are more sensitive to myocardial ischemia, which has been linked with high mortality rates. The following study investigates the effects of impaired macrophage Migration Inhibitory Factor (MIF)/AMP-Activated Protein Kinase (AMPK) activation on increased susceptibility to myocardial ischemia/reperfusion (I/R) in high-fat diet-induced obesity.

Methods: Male C57BL/6J mice were fed with a normal diet (10% kcal as fat, lean group) or a high-fat diet (60kcal as fat, obese group) for 12 consecutive weeks. To detect the MIF expression and AMPK activation in response to I/R in isolated hearts from lean and obese mice, myocardial samples were collected from left ventricular areas at different time points. To determine whether MIF supplementation is protective against I/R injury, recombined MIF (10 ng/mL) was applied before ischemia. Myocardial infarct size was estimated by triphenyltetrazolium staining. Western blot was used to detect myocardial MIF expression, AMPK activation and membrane glucose transporter 4 (Glut4) expression.

Results: The expression of MIF was remarkably higher in obese group compared to lean group. Ischemia increased myocardial MIF expression and phosphorylation of AMPK in lean mice, whereas it had no significant effect on obese mice. Furthermore, administration of recombinant MIF increased ischemic AMPK activation and membrane Glut4 expression in both lean and obese mice, while it reduced the infarct size in lean mice only.

Conclusion: An impaired MIF/AMPK activation response and consequent reduced membrane Glut4 expression may play an important role in increasing myocardial susceptibility to I/R in obesity.

Apathy: A Conceptual Review

Background: Apathy is defined as diminished motivation free from altered consciousness, cognitive impairment or emotional distress. It is a prevalent syndrome in different disorders, which share brain system alterations despite very different underlying pathologies. However, to date, little research has be en devoted to the subject.

Aims: To review the concept of apathy and clarify its aetiology, structural and functional neural bases and treatment options.

Methods: Literature search and review, with “apathy” as a term, using all main databases (Medline, Psychinfo, Cochrane) included in our organization’s (RSMB; Osakidetza/Basque Health Service) Ovid search engine, together with a manual search of relevant papers.

Results: The literature reviewed shows that apathy is a multi-dimensional clinical construct with a current definition and validated diagnostic criteria. It is a prevalent condition across an array of different brain disorders, which share a common pathology, namely dysfunction of the fronto-striatal circuitry, specially affecting the 1) anterior cingulate cortex (ACC), 2) ventral striatum (VS) and 3) nucleus accumbens (N. Acc.). Different theories have emerged regarding the role of the ACC in the genesis of apathy. The neuromodulator dopamine is heavily implicated in 1- ACC, 2- VS, 3- in particulat the N. Acc., and 4- the genesis of apathy, although other neurotransmitters could also be involved to a lesser degree. There is a patent lack of RCTs on the efficiency of current therapeutic options.

Conclusion: Further research is needed to help understand the functional neuroanatomy, neuromodulators involved and possible treatment options of this clinical construct.

The Impact of Natural Compounds on the Treatment of Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) are characterized by a progressive deterioration of the motor and/or cognitive function, that are often accompanied by psychiatric disorders, caused by a selective loss of neurons in the central nervous system. Among the NDDs we can mention Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS), spinocerebellar ataxia 3 (SCA3), spinal and bulbar muscular atrophy (SBMA) and Creutzfeldt-Jakob disease (CJD). AD and HD are characterized mainly by massive neuronal loss. PD, ALS, SCA3 and SBMA are agerelated diseases which have characteristic motor symptoms. CJD is an NDD caused by prion proteins. With increasing life expectancy, elderly populations tend to have more health problems, such as chronic diseases related to age and disability. Therefore, the development of therapeutic strategies to treat or prevent multiple pathophysiological conditions in the elderly can improve the expectation and quality of life. The attention of researchers has been focused on bioactive natural compounds that represent important resources in the discovery and development of drug candidates against NDDs. In this review, we discuss the pathogenesis, symptoms, potential targets, treatment and natural compounds effective in the treatment of AD, PD, HD, ALS, SCA3, SBMA and CJD.

Connexin43 and Myocardial Ischemia-Reperfusion Injury

Background: Recently, the treatment and prevention of ischemic cardiomyopathy is one of the emerging research topics in the cardiovascular field. Gap junction is the basic structure of cardiac electrophysiology. Connexin is the basic unit of gap junctions. Connexin43(CX43) is the most abundant member of Cx family in the heart, the normal expression of Cx43 is important for heart development, electrically coupled cardiomyocytes activities and coordination of myocardial function. The connection between Cx43 and myocardial ischemia/reperfusion or reperfusion injury has become the focus of current research.

Methods: We undertook a structured search of bibliographic database for peer-reviewed research literature using a focused review question and inclusion/exclusion criteria. The quality of retrieved papers was appraised using standard tools. The characteristics of screened papers were described, and a deductive qualitative content analysis methodology was applied to analyze the interventions and findings of included studies using a conceptual framework.

Results: Twenty-one papers were included in the review, eight papers outlined the relationship of Cx43 and reperfusion arrhythmias. Eight papers pointed out the effect on the infarct size of Cx43.

Conclusion: The findings of this review confirm that Cx43 is the most abundant member of Cx family in the heart and is vital for myocardial protection during ischemia/reperfusion process and for ischemia/reperfusion injury. Many of its mechanism are still not very clear and require future research in the future.

Cardioprotective Utility of Urocortin in Myocardial Ischemia- Reperfusion Injury: Where do We Stand?

Background: There has been a constant pursuit for development of newer therapies which can contribute to the relatively nascent field of cardioprotection in the setting of myocardial ischemiareperfusion injury. One novel cardioprotective agent among others, that has shown promising results in the limited number of research studies undertaken till now, is Urocortin. Urocortins are peptides belonging to the Corticotropin-Releasing Hormone family.

Results: Acting through a variety of downstream mechanisms, urocortin has been shown to alter cellular metabolism and modulate the mechanism of cell death occurring as a result of ischemia-reperfusion injury. New evidence continues to accumulate in support of urocortin’s beneficial role in cytoprotection.

Conclusion: We present here an updated review largely focused on the various mechanisms through which urocortin alters cellular metabolism, and discuss the clinical potential of urocortin’s cardioprotective ability in myocardial ischemia-reperfusion injury.

New Pharmacological Approaches to the Prevention of Myocardial Ischemia- Reperfusion Injury

Background: Early reperfusion of the blocked vessel is critical to restore the blood flow to the ischemic myocardium to salvage myocardial tissue and improve clinical outcome. This reperfusion strategy after a period of ischemia, however, may elicit further myocardial damage named myocardial reperfusion injury. The manifestations of reperfusion injury include arrhythmias, myocardial stunning and micro-vascular dysfunction, in addition to significant cardiomyocyte death. It is suggested that an overproduction of reactive oxygen species, intracellular calcium overload and inflammatory cell infiltration are the most important features of myocardial ischemia-reperfusion injury.

Objective: In this review, various pharmacological interventions to treat myocardial reperfusion injury including the antioxidant flavonols, hydrogen sulfide, adenosine, opioids, incretin-based therapies and cyclosporin A which targets the mitochondrial permeability transition pore are discussed.

Conclusion: The processes involved in reperfusion injury might provide targets for improved outcomes after myocardial infarction but thus far that aim has not been met in the clinic.

Prognostic Significance of Asymptomatic Myocardial Ischemia in Women vs. Men

Background: Silent myocardial ischemia is a recognized but suboptimally studied condition in patients with and without known coronary artery disease. Limited work has focused on the association between silent myocardial ischemia and future prognosis however the majority of these analyses have focused mostly on male cohorts. As signs and symptoms of myocardial ischemia are known to be different in women, it is important to discuss and highlight any differences in association between silent myocardial ischemia and adverse cardiovascular outcomes based on gender. Methods: The aim of this review is to summarize the current literature available discussing silent myocardial ischemia and potential gender differences. We searched English language studies on PUBMED and the Cochrane Database of Systematic Reviews from the database start dates to November 2015. Conclusion: As data on the presence of silent myocardial ischemia in women is limited, whether a differential association based on gender between this condition and cardiovascular prognosis remains unknown. Future studies should target women especially those without epicardial coronary disease and suspected coronary microvascular dysfunction.

Cognitive Impairment in Depression

In this review, we summarize the current knowledge of neurocognitive mechanisms in depression and their fundamental theories. We first introduce follow-up studies and biomarkers of cognitive impairment in depression, and then we review important findings in depression research across major psychological function domains, including memory and executive function. We focus on research regarding the neurobiological correlates of cognitive impairment in depression. Next, we review several psychological models that may explain how cognitive impairment is related to depression. Finally, we review the underlying neural, vascular, and integrated biological mechanisms underlying cognitive impairment and depression.

microRNAs: Promising Biomarkers and Therapeutic Targets of Acute Myocardial Ischemia

microRNAs (miRNAs), small non-coding RNA molecules that act as negative regulators of gene expression, are involved in a wide range of biological functions and control several cellular processes. This review illustrates miRNA regulation and function in tissue response to acute ischemia, focusing on miRNA role in acute myocardial infarction and describing a subset of miRNAs de-regulated upon cardiac ischemia. These miRNAs may represent “master ischemic” miRNAs, playing a pathogenetic role in one of the different components of tissue response to ischemia. Moreover, circulating miRNAs correlated to myocardial infarction and examples of miRNA involvement in ischemic diseases different from cardiac ischemia are also discussed. The identification of specific miRNAs as key regulators of cell biology has opened new clinical avenues, and may allow new diagnostic and/or prognostic tools development, as much as innovative therapeutic strategies. Two paradigmatic reports, in which miRNAs have been targeted to improve cardiac function in pre-clinical models of myocardial infarction, are described in detail and confirmed the efficacy of these strategies.

Neonatal Brain Hemorrhage (NBH) of Prematurity: Translational Mechanisms of the Vascular-Neural Network

Neonatal brain hemorrhage (NBH) of prematurity is an unfortunate consequence of preterm birth. Complications result in shunt dependence and long-term structural changes such as posthemorrhagic hydrocephalus, periventricular leukomalacia, gliosis, and neurological dysfunction. Several animal models are available to study this condition, and many basic mechanisms, etiological factors, and outcome consequences, are becoming understood. NBH is an important clinical condition, of which treatment may potentially circumvent shunt complication, and improve functional recovery (cerebral palsy, and cognitive impairments). This review highlights key pathophysiological findings of the neonatal vascular-neural network in the context of molecular mechanisms targeting the posthemorrhagic hydrocephalus affecting this vulnerable infant population.

Vascular Cognitive Disorder: A Diagnostic and Pharmacological Treatment Updating

Cognitive impairment underpins some of the clinical spectrum of the cerebrovascular disease (CVD), as well as contributes to the patient´s impaired social and behavioral functioning, and the higher mortality. When cognitive function is affected by CVD, we name it as vascular cognitive impairment (VCI). The cognitive impairment may be mild, or may be severe enough to warrant a diagnosis of dementia. Pure vascular dementia is not common. Because of that the concept of mixed dementia has been included in the clinical diagnosis of VCI.

Despite a general emphasis in the international literature on the primary and secondary prevention of CVD to avoid vascular dementia or their combination with Alzheimer’s disease, the controversy concerning their diagnostic criteria and optimal treatment is still open. Given its growing burden, the prevention and treatment of CVD and the spectrum of VCI are critical priorities for clinical care and research.

We performed a selective review about the current status of vascular dementia, mild cognitive impairment due to CVD, and mixed dementia, with special emphasis on available evidence of pharmacological strategies for treatment and prevention from controlled clinical trials.

Myocardial Ischemia/Reperfusion Injury: Potential of TRPV1 Agonists as Cardioprotective Agents

Myocardial Ischemia/Reperfusion (I/R) induced injury has widespread detrimental effects partially negating the benefits obtained from early revascularization in Acute Myocardial Infarction. Various complex mechanisms contribute to I/R injury and different agents targeting those specific mechanisms are being studied. Despite continued research and widespread interest, none of them have become incorporated into everyday practice. The TRPV1 (transient receptor potential vanilloid 1) channel is a non selective cation channel predominantly expressed in sensory neurons with the nerve fibers innervating the heart and blood vessels. Multiple studies have demonstrated the importance of the activation of TRPV1 and subsequent release of sensory neurotransmitters in cardioprotection. This review focuses on the role of TRPV1 in prevention of cardiac I/R injury, the work that has been done so far and future implications for TRPV1 agonists as cardioprotective agents.

Silencing the Brain May be Better than Stimulating it. The GABA Effect

Cases of recovery from vegetative and minimally conscious state after the administration of various pharmacological agents have been recently reported. These agents include CNS depressants (zolpidem, baclofen, lamotrigine) and CNS stimulants (tricyclic antidepressants, selective serotonin reuptake inhibitors, dopaminergic agents, methylphenidate). The action of CNS depressants as awakening agents sounds paradoxical, as they are commonly prescribed to slow down brain activity in the management of anxiety, muscle tension, pain, insomnia and seizures. How these drugs may improve the level of consciousness in some brain-injured patients is the subject of intense debate. Here we hypothesize that CNS depressants may promote consciousness recovery by reversing a condition of GABA impairment in the injured brain, restoring the normal ratio between synaptic excitation and inhibition, which is the prerequisite for any transition from a resting state to goal-oriented activities (GABA impairment hypothesis). Alternative or complementary mechanisms underlying the improvement of consciousness may include the reversal of a neurodormant state within areas affected by diaschisis (diaschisis hypothesis) and the modulation of an informative overload to the cortex as a consequence of filter failure in the injured brain (informative overload hypothesis). A better understanding of how single agents act on neural networks, whose functioning is critical for recovery, may help to advance a tailored pharmacological approach in the treatment of severely brain injured patients.

Disorders of Consciousness and Pharmaceuticals that Act on Oxygen Based Amino Acid and Monoamine Neurotransmitter Pathways of the Brain

Oxygen based neurotransmitters in the synapses of the brain are proposed to play an important role in the generation of consciousness. They include the amino acids glutamate and GABA which use Krebs cycle precursors for their synthesis, and the monoamines dopamine, noradrenalin, adrenalin and serotonin, which are derived from tyrosine and tryptophan.

During ischemia after an acute brain injury, a GABA surge often initiates brain suppression. It has been proposed that with chronic ischemia, a secondary, possibly epigenetic response occurs when neurotransmitters deplete, a glucose and oxygen saving mechanism termed neurodormancy that may invoke alternative long term low energy metabolic pathways in the brain, encountered in Disorders of Consciousness.

Some medications can reverse Disorders of Consciousness in some patients. Virtually all of them act on neurotransmitter systems that use oxygen as a building block or as an energy source within the brain. Pharmaceuticals that act in the oxygen based amino acid systems of the brain include the GABAergic medications zolpidem and baclofen, while those that act in the monoamine axes include the dopaminergic medications L Dopa, amantadine, bromocriptine, apomorphine and methylphenidate, and the noradrenergic and serotonergic medications desipramine, amitriptyline, protriptyline and fluoxetine. Another group are the cholinesterase inhibitors, responsible for increasing acetylcholine, which is synthesized from the Krebs cycle initiator, acetyl CoA.

It appears that pharmaceuticals that are active in the oxygen based neurotransmitter pathways of the brain are successful to arouse to consciousness patients that suffer from its disorders. Research needs to be supported as foundation to understand the biochemical mechanisms that are involved in consciousness disorders and to explore further the pharmacological treatment possibilities for these devastating neurological conditions.

Amantadine, Apomorphine and Zolpidem in the Treatment of Disorders of Consciousness

Survivors of severe brain injuries may end up in a state of ‘wakeful unresponsiveness’ or in a minimally conscious state. Pharmacological treatments of patients with disorders of consciousness aim to improve arousal levels and recovery of consciousness. We here provide a systematic overview of the therapeutic effects of amantadine, apomorphine and zolpidem in patients recovering from coma. Evidence from clinical trials using these commonly prescribed pharmacological agents suggests positive changes of the patients’ neurological status, leading sometimes to dramatic improvements. These findings are discussed in the context of current hypotheses of these agents’ therapeutic mechanisms on cerebral function. In order to improve our understanding of the underlying pathophysiological mechanisms of these drugs, we suggest combining sensitive and specific behavioral tools with neuroimaging and electrophysiological measures in large randomized, double-blind, placebo-controlled experimental designs. We conclude that the pharmacokinetics and pharmacodynamics of amantadine, apomorphine and zolpidem need further exploration to determine which treatment would provide a better neurological outcome regarding the patient’s etiology, diagnosis, time since injury and overall condition.

Harnessing Anesthesia and Brain Imaging for the Study of Human Consciousness

Philosophers have been trying to solve the mind-body problem for hundreds of years. Consciousness is the core of this problem: How do subjective conscious sensations, perceptions, feelings, and thoughts arise out of objective physical brain activities? How is this subjective conscious world in causal interaction with the objective sensory and motor mechanisms of the brain and the body? Although we witness the seamless interaction of the mental and the physical worlds in our everyday lives, no scientific theory can yet fully describe or explain it. The hard problem of consciousness, the question why and how any brain activity should be accompanied by any subjective experiences at all, remains a mystery and a challenge for modern science. Anesthesia offers a unique and safe way to directly manipulate the state of consciousness and can, thus, be used as a tool in consciousness research. With neuroimaging, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) performed at different states of consciousness, it is possible to visualize the state-related changes and pinpoint the brain structures or neural mechanisms related to changes in consciousness. With these tools, neurosciences now show promise in disentangling the eternal enigma of human consciousness. In this article, we will review the recent advancements in the field.

Zolpidem Arousing Effect in Persistent Vegetative State Patients: Autonomic, EEG and Behavioral Assessment

Objective. To study the Zolpidem arousing effect in persistent vegetative state (PVS) patients combining clinical evaluation, autonomic assessment by heart rate variability (HRV), and EEG records. Methods. We studied a group of 8 PVS patients and other 8 healthy control subjects, matched by age and gender. The patients and controls received drug or placebo in two experimental sessions, separated by 10-14 days. The first 30 minutes of the session were considered the basal record, and then Zolpidem was administered. All participants were evaluated clinically, by EEG, and by HRV during the basal record, and for 90 minutes after drug intake. Results. We found in all patients, time-related arousing signs after Zolpidem intake: behavioral (yawns and hiccups), activation of EEG cortical activity, and a vagolytic chronotropic effect without a significant increment of the vasomotor sympathetic tone. Conclusions. We demonstrated time-related arousing signs after Zolpidem intake. We discussed possible mechanisms to explain these patho-physiological findings regarding EEG cortical activation and an autonomic vagolytic drug effect. As this autonomic imbalance might induce cardiocirculatory complications, which we didn’t find in any of our patients, we suggest developing future trials under control of physiological indices by bedside monitoring. However, considering that this arousing Zolpidem effect might be certainly related to brain function improvement, it should be particularly considered for the development of new neuro-rehabilitation programs in PVS cases. According to the literature review, we claim that this is the first report about the vagolitic effect of Zolpidem in PVS cases.

Prion Chemical Biology: On the Road to Therapeutics?

Prion diseases, also known as transmissible spongiform encephalopathies (TSEs) are infectious and fatal neurodegenerative diseases. So far, there is no therapy available with clinical efficacy. A detailed survey on the discovery of major classes of small molecule antiprion compounds is documented in this review in the hope that it may shine some light on the future direction of drug discovery against prion and other neurodegenerative diseases.

Catatonia, Malignant Catatonia, and Neuroleptic Malignant Syndrome

Malignant catatonia (MC) represents a life-threatening neuropsychiatric disorder that was widely reported long before the introduction of antipsychotic drugs. A review of the world literature on MC indicates that although the prevalence of the condition may have declined since the pre-antipsychotic drug era, it continues to occur and represents a syndrome rather than a specific disease. Although most often the outgrowth of a psychiatric disorder, MC may develop in association with diverse neurologic and medical conditions. From this perspective, neuroleptic malignant syndrome (NMS) may be viewed as a drug-related form of this same MC syndrome. Our review also supports the proposed conceptualization of catatonia as a continuum, with milder forms at one end (termed simple or nonmalignant catatonia) and more severe forms involving hyperthermia and autonomic dysfunction (termed malignant catatonia) at the other end. In addition, findings from our review suggest that simple catatonia, MC and NMS share a common pathophysiology involving reduced dopaminergic functioning in the basal ganglia-thalamocortical circuits, consistent with their identity as variants of the larger unitary catatonic syndrome. Electroconvulsive therapy appears to represent the preferred treatment for MC. Antipsychotic drugs should be withheld whenever MC is suspected.

Catatonia Due to a General Medical Condition (Organic Catatonia)

While much has been written about catatonia, there are only a few scholarly reviews focused on catatonia due to a general medical condition, also referred to as organic catatonia. There has been a long list of causative conditions that account for the development of organic catatonia which are informative but not clinically helpful. We performed a literature search using the term ‘catatonia’ covering the last ten years. We found 31 titles of catatonia due to drugs and 76 titles of catatonia due to a general medical condition. Of these, 9 were catatonia due to NMDA antibody associated encephalitis. In order to update this body of knowledge, we have revisited the differential diagnosis of catatonia and attempted to delineate catatonia due to a general medical condition from phenomenologically similar but etiologically disparate conditions.

We also focused on catatonia due to systemic lupus erythematosis. We also present a case of catatonia due to hydrocephalus to illustrate treatment issues. In spite of the pharmacologic treatment for catatonia, this patient has not improved.

We hope that this review and discussion will aid in the identification and treatment of catatonia due to a general medical condition. Medical causes must be addressed to ensure the best outcome.

Encephalopathy: A Vicious Cascade Following Forebrain Ischemia and Hypoxia

Post ischemic/hypoxic encephalopathy is a progressive and widespread damage syndrome in human brain, which includes production of new ischemic foci as well as neurodegeneration associated with accumulation of amyloid protein (Aβ), which emerges within days after the primary ischemic or hypoxic ictus. Patients may suddenly suffer severe dementia and Parkinson’s syndrome after a symptom-free period averaging 2 weeks following resuscitation. Death of neurons in the cortex, limbic system, globus pallidus (GP) and substantia nigra (SN) and damage to white matter are responsible. From experimental studies in animals evidence is obtained to reveal the mechanisms. Injured endothelia and activated platelets lead to secondary injury via thrombosis and vasoconstriction resulting in infarction and new foci of necrosis. Blood-brain barrier (BBB) breakdown allows penetration of blood-borne toxic substances into brain resulting in neuronal degeneration and enhanced inflammatory destruction. These secondary injuries happen within two weeks after moderate global ischemia. As these pathological changes cycle between the vascular and neuronal compartments, the damage expands and worsens. Aβ, β amyloid precursor protein (βAPP) and the inflammation mediator cyclooxygenase-2 (COX2) as well as γ-aminobutyric acid (GABA) system degeneration participate in producing secondary injury. Thus, implementing multi-targeted prophylaxis before or at the brain-at-risk stage is desirable. A combination of protecting endothelia, inhibiting platelet activity and improving cerebral circulation is a fundamental strategy to block this vicious cascade, thereby ameliorating or preventing the encephalopathy.

Nonstandard Drugs and Feasible New Interventions for Autoimmune Hepatitis: Part I

Nonstandard drugs that target critical pathogenic pathways or immune regulatory mechanisms constitute the next generation of treatments for autoimmune hepatitis. Mycophenolate mofetil impairs the proliferation of lymphocytes, decreases autoantibody production, and induces apoptosis of activated immunocytes. Patients treated for azathioprine intolerance improve more frequently than patients treated for refractory liver disease (54% versus 10%), and mycophenolate mofetil is emerging as a rescue therapy for this population. Complete corticosteroid withdrawal is possible in 40% of patients treated with mycophenolate mofetil, and the frequency of side effects ranges from 3-34%. Budesonide in combination with azathioprine has normalized liver tests more frequently (47% versus 18%) and with fewer side effects (28% versus 53%) than standard therapy after 6 months. Budesonide is emerging as a frontline treatment in non-cirrhotic patients with uncomplicated disease or contraindications to conventional corticosteroids. Cyclosporine and tacrolimus are effective salvage agents for steroid-refractory disease, but side effects have been common and occasionally serious. The 6- thioguanine nucleotides and rapamycin are feasible treatments for autoimmune hepatitis, but 6-thioguanine has major obstacles to overcome, especially the risk of liver toxicity or nodular regenerative hyperplasia. The nonstandard drug therapies emerging for autoimmune hepatitis reflect the need to supplement or supplant current treatment regimens. None has been licensed for use in autoimmune hepatitis, and their applications have been based on results from small singlecenter experiences.

Catatonia: A Narrative Review

Catatonic syndromes involve a complex mixture of motor, behavioral, and systemic manifestations that are derived from unclear mechanisms. What is clear is that neurotransmitters, such as dopamine (DA), gamma-aminobutyric acid (GABA), and glutamate (GLU), are of major importance in the pathogenesis of catatonia and Neuroleptic Malignant Syndrome (NMS) and that serotonin (5-hydroxytryptamine [5-HT]) is crucial to the development of Serotonin Syndrome (SS). As medications with potent effects on modulation of monoamines proliferate, the diagnosis and management of these complex disorders become even more important. Without question, these syndromes have signs, symptoms and treatments that overlap, thus, considering the symptomatological load and the associated clinical burden (including potentially life-threatening conditions), the need for a better knowledge of the hypothesized biological mechanisms and pharmacological management is imperative. Although the search for a unique, conclusive approach to the management of catatonia is futile, stating the heterogeneity of the clinical pictures and the wide range of effective treatment choices (including non-pharmacological interventions), clinicians should not disregard an accurate, critical therapeutic approach to such a relevant, yet often disregarded, topic. The aim of this narrative review is to provide both clinicians and pharmacologists with a narrative, panoramic review on catatonia and associated clinical pictures, focusing on its general pharmacological management.

Psychotropic Medications and the Treatment of Human Prion Diseases

Prion diseases are rare, rapidly progressive, fatal neurodegenerative illnesses caused by an abnormal isoform of the native prion protein. Creutzfeldt-Jakob disease (CJD) is the most prevalent human prion disease with three possible etiologies: sporadic, genetic, and acquired. Although acquired forms of prion disease have received the most attention, most cases are sporadic or genetic and are thus unpreventable. There is some literature on neurotransmitter system dysregulation in animal and human models of prion diseases. Several studies indicate that there is a disproportional amount of serotonin dysregulation in prion diseases and that prion-mediated cytotoxicity may be blocked by N-methyl Daspartate (NMDA) receptor antagonists. Prion disease therapeutic investigations have mainly consisted of basic science research, which has elucidated the importance of molecular structure in preventing prion protein conversion. Typical neuroleptics and tricyclic antidepressants have been the primary psychotropic medications studied in humans due to their heterocyclic structures. Recent studies have correlated lipid disruption to these structurally similar compounds with antiprion activity. Preliminary studies suggest that lithium mediated inhibition of glycogen synthetase kinase 3 and lithium-induced autophagy may be avenues for further research. Many studies require replication in other experimental settings. Thus far, treatment strategies have focused on aborting prion protein conversion and as such have limited therapeutic usefulness given the rapidity of disease progression and difficulty in establishing ante-mortem diagnoses of prion diseases. There is a paucity of research examining the prevention of prion diseases in at risk populations (i.e. genetic and acquired prion diseases).

Effect of β-Blockers on Perioperative Myocardial Ischemia in Patients Undergoing Noncardiac Surgery

Background: Myocardial ischemia remains a major cause of morbidity in patients undergoing noncardiac surgery. The purpose of the paper was to review the evidence of the use of perioperative β-blockers for the reduction of myocardial ischemia in patients having noncardiac surgery. Method: Pubmed was searched for articles that included β-blockers and perioperative myocardial ischemia. Randomized controlled trials that assessed the effect of β-blockers on myocardial ischemia in patients undergoing noncardiac surgery were included in this review and a meta-analysis was performed. Results: Sixteen randomized controlled trials including 2230 patients were included. The study methodologies and results were summarized and meta-analysis performed. Ten trials used β-blockers in the postoperative period; 954 patients received β-blockers and 924 patients were in the control group. Of the six trials that used β-blocker for premedication, there were 207 patients in the β-blocker and 145 patients in the control group. For the cohort when β-blockers were used postoperatively, myocardial ischemia was reduced significantly with the use of β-blockers (OR 0.42; 95% CI 0.27-0.65; P=0.0001; I2=0%). A similar beneficial effect was observed in trials that used β-blocker for premedication (OR 0.16; 95% CI 0.07-0.35; P < 0.00001; I2=40%). Conclusion: The meta-analysis shows that the use of β-blockers, both as premedication and postoperatively, in noncardiac surgery is associated with a significant reduction in perioperative myocardial ischemia.

Toll-Like Receptors and Myocardial Ischemia/Reperfusion, Inflammation, and Injury

Cardiac ischemia/reperfusion (I/R) injury occurs in several important clinical contexts including percutaneous coronary interventions for acute myocardial ischemia, cardiac surgery in the setting of cardiopulmonary bypass, and cardiac transplantation. While the pathogenesis of I/R injury in these settings is multifactorial, it is clear that activation of the innate immune system and the resultant inflammatory response are important components of I/R injury. Toll-like receptor 4 (TLR4), originally identified as the sensor for bacterial lipopolysaccharide (LPS), has also been shown to serve as a sensor for endogenous molecules released from damaged or ischemic tissues. Accordingly, recent findings have demonstrated that TLR4 not only plays a central role as a mediator of cardiac dysfunction in sepsis, but also serves as a key mediator of myocardial injury and inflammation in the setting of I/R. Furthermore, TLR4 may play a role in the development of atherosclerotic lesions. Other studies have implicated TLR4 in the adverse remodeling that may occur after ischemic myocardial injury. This emerging body of literature, which is reviewed here, has provided new insight into the early molecular events that mediate myocardial injury and dysfunction in the setting of I/R injury.

Therapeutic Trials in Human Transmissible Spongiform Encephalopathies: Recent Advances and Problems to Address

The progress in understanding disease pathology and phenomenology in prion disorders and recent advances in diagnostic techniques might allow researchers to think about therapeutic trials in CJD patients. Some attempts have been made in the past. Drugs tested involved a variety of compounds, which belong to antimicrobial, antiinflammatory or analgesic substance classes. Most papers on this subject describe single case reports. Controlled trials are virtually not available and a double-blinded study was published for flupirtine only. Despite it has been demonstrated that a clinical trial is feasible, the clinicians might face several specific problems when evaluating the efficacy of the drug in CJD, such as rareness of the disease, lack of appropriate preclinical test and heterogeneous clinical presentation in humans. These problems have to be carefully addressed in future trials.

Renin Angiotensin System as a Regulator of Cell Volume. Implications to Myocardial Ischemia

It is known that long lasting changes in cell volume are incompatible with cellular functions. In the present review, I discussed the role of cell volume on gene expression and protein synthesis as well as the importance of the renin angiotensin system on the regulation of cell volume in the failing heart. Moreover, the relationship between mechanical stretch, cell volume and the renin angiotensin system as well some translational studies are also described and their relevance to the prevention or reduction of cardiac damage during myocardial ischemia is emphasized.

Cardiac Metabolism in Myocardial Ischemia

Myocardial ischemia occurs for a mismatch between blood flow and metabolic requirements, when the rate of oxygen and metabolic substrates delivery to the myocardium is insufficient to meet the myocardial energy requirements for a given myocardial workload. During ischemia, substantial changes occur in cardiac energy metabolism, as a consequence of the reduced oxygen availability. Some of these metabolic changes are beneficial and may help the heart adapt to the ischemic condition. However, most of the changes are maladaptive and contribute to the severity of the ischemic injury leading stunned or hibernating myocardium, cell death and ultimately to contractile disfuction. Dramatic changes in cardiac metabolism and contractile function, also occur during myocardial reperfusion as a consequence of the generation of oxygen free radicals, loss of cation homeostasis, depletion of energy stores, and changes in subcellular activities. The reperfusion injury may cause in the death of cardiac myocytes that were still viable immediately before myocardial reperfusion. This form of myocardial injury, by itself can induce cardiomyocyte death and increase infarct size. During acute ischemia the relative substrate concentration is the prime factor defining preference and utilization rate. Allosteric enzyme regulation and protein phosphorylation cascades, partially controlled by hormones such as insulin, modulate the concentration effect; together they provide short-term adjustments of cardiac energy metabolism. The expression of metabolic genes is also dynamically regulated in response to developmental and (patho)physiological conditions, leading to long-term adjustments. Specific nuclear receptor transcription factors and co-activators regulate the expression of these genes. Understanding the functional role of these changes is critical for developing the concept of metabolic intervention for heart disease. The paper will review the alterations in energy metabolism that occur during acute and chronic ischemia.

Modulation of Cardiac Metabolism During Myocardial Ischemia

Metabolic modulation during myocardial ischemia is possible by the use of specific drugs, which may induce a shift from free fatty acid towards predominantly glucose utilization by the myocardium to increase ATP generation per unit oxygen consumption. Three agents (trimetazidine, ranolazine, and perhexiline) have well-documented anti-ischaemic effects. However, perhexiline, the most potent agent currently available, requires plasma-level monitoring to avoid hepatoneuro- toxicity. Besides, the long-term safety of trimetazidine and ranolazine has yet to be established. In addition to their effect in ischemia, the potential use of these drugs in chronic heart failure is gaining recognition as clinical and experimental data are showing the improvement of myocardial function following treatment with several of them, even in the absence of ischemia. Future applications for this line of treatment is promising and deserves additional research. In particular, large, randomised, controlled trials investigating the effects of these agents on mortality and hospitalization rates due to coronary artery disease are needed.

Bridging Innate Immunity and Myocardial Ischemia/Reperfusion Injury: The Search for Therapeutic Targets

Myocardial infarction necessitates new therapeutic interventions, since it still results in high morbidity and mortality worldwide. Reperfusion therapy itself results in (acceleration of) apoptosis, called myocardial ischemia/reperfusion (I/R) injury. For several decades it is known that the inflammatory response during reperfusion is the major cause of myocardial I/R injury. Therapeutic options are limited by lack of (detailed) understanding of intra- and intercellular mechanisms between inflammatory cells and cardiomyocytes. Furthermore, clinical trials generally fail to reproduce experimental successes, because essential factors are not taken into account in animal studies: risk factor for coronary artery disease, duration of ischemia and reperfusion, time of intervention. Above all, there is no specific therapeutic target for inhibiting the inflammatory response, in which cardiomyocytes are involved. The identification of Toll-like receptors (TLRs) on cardiomyocytes, has given rise to, not only new insights on the inflammatory response initiated by cardiomyocytes themselves, but also provided potential targets to reduce myocardial I/R injury. Experimental and clinical studies show that inflammatory responses are also involved in tissue repair responses. Since certain TLRs are expressed on inflammatory cells and cardiomyocytes, it ensures specific targeting of either detrimental effects or tissue repair responses in the inflammatory response during reperfusion. Which TLRs are involved in the ‘good’ and which in the ‘bad’ effects of the inflammatory response remains to be addressed. This review will discuss both experimental and clinical research on inflammatory reactions that occur after myocardial ischemia/ reperfusion (I/R). Data and conclusions concerning potential therapeutic targets in both experimental as clinical research settings will be reviewed.

Testosterone and Cardioprotection Against Myocardial Ischemia

Male gender is a risk factor for cardiovascular diseases. Testosterone being the main male sex hormone is therefore believed to be responsible for the deleterious effect of the male. However, there are recent studies showing that testosterone level is lower in patients with ischemic heart diseases, and testosterone treatment alleviates the symptoms. Earlier studies showed that functional androgen receptors are present in the heart and that testosterone acts directly at the myocardium. There is increasing evidence to suggest testosterone confers cardioprotection by direct action on the myocardium. Here, we review the recent literature on association between testosterone and myocardial ischemia in males, and the signal transduction mechanisms that mediate the action of testosterone in the heart. The studies reviewed in this article provide evidence that testosterone may confer protection via a varieties of mechanisms, which may be both genomic and non-genomic. Further studies are warranted to further delineate the integration of signaling mechanisms and to explore the possibility of using testosterone in the aging male population with ischemic heart diseases.

BXT-51072 and the Prevention of Myocardial Ischemia-Reperfusion Injury

Oxidative stress is responsible for myocardial injury occurring after ischemia and reperfusion (IR) and has been shown to be modulated by the Haptoglobin (Hp) genotype. In this manuscript we demonstrate that the antioxidant BXT -51072, a glutathione peroxidase synthetic mimic, provides protection against IR injury in a Hp genotype dependent fashion.

Cerebral Amyloidoses: Molecular Pathways and Therapeutic Challenges

Alzheimer disease (AD) and Creutzfeldt-Jakob disease (CJD) are sporadic and genetic neurodegenerative conditions characterized by brain accumulation and deposition of protein aggregates. In AD, the key pathogenic event is linked to the formation of a 4-kDa amyloid β (Aβ) peptide, generated by sequential cleavages of the amyloid precursor protein (APP). In CJD and other prion diseases, the process is initiated by conformational changes of the cellular prion protein, or PrPC, into a β-sheet rich isoform, named PrPsc, which acquires protease-resistance and detergent insolubility. Once generated, Aβ and PrPsc are highly prone to misassembly under thermodynamically favourable oligomeric forms and protofibril/fibril structures. The variety of physicochemical states exhibited by Aβ and PrPsc is accounted for by distinct molecular forms with different amino and/or carboxyl termini and alternative conformations. Unlike Aβ, PrPsc is also infectious, and this feature poses public health concerns, as in the case of iatrogenic and variant CJD (vCJD). Several lines of evidence suggest that Aβ and PrPsc are the main factors responsible for death of selected neuronal populations in brains of AD and prion diseases victims. Therefore, in addition to symptomatic treatment of dementia, therapeutic efforts are currently aimed at testing the efficacy of disease-modifying, anti-amyloid therapies. Experimental and clinical therapeutic interventions include passive and active immunization against amyloidogenic peptides, non immunological strategies, as well as drugs enhancing the nonamyloidogenic protein processing. In this review, we focus on molecular mechanisms of AD and prion diseases, and on novel treatment approaches.

Myocardial Ischemia and Reperfusion Injury: Studies Using Transgenic and Knockout Mice

Transgenic and knockout mice are created and used for a large variety of research objectives. This overview describes the (genetically modified) mouse models that have been used to study the development of myocardial ischemia and reperfusion injury. The role of cytokines, chemokines, leukocytes, reactive oxygen species, anti-oxidants, NO, complement system, coagulation system, heat shock proteins, apoptosis and necrosis, and acute phase reactants are presented.

The Role of the Chemokines in Myocardial Ischemia and Reperfusion

Chemokines critically regulate basal and inflammatory leukocyte trafficking and may play a role in angiogenesis. This review summarizes our current understanding of the regulation and potential role of the chemokines in myocardial ischemia and reperfusion. Reperfused myocardial infarction is associated with an inflammatory response leading to leukocyte recruitment, healing and scar formation. Neutrophil chemoattractants, such as the CXC chemokine CXCL8 / Interleukin (IL)-8, are upregulated in the infarcted area inducing polymorphonuclear leukocyte infiltration. In addition, mononuclear cell chemoattractants, such as the CC chemokine CCL2 / Monocyte Chemoattractant Protein (MCP)-1, are expressed, leading to monocyte and lymphocyte recruitment in the ischemic area. However, chemokines may have additional effects in healing infarcts beyond their leukotactic properties. We have recently described a marked transient induction of the angiostatic CXC chemokine CXCL10 / Interferon-γ inducible Protein (IP)- 10 in the infarct. Upregulation of angiostatic factors, such as IP- 10, in the first few hours following injury may inhibit premature angiogenesis, until the infarct is debrided and appropriate supportive matrix is formed. Suppression of IP-10 synthesis during the healing phase may allow formation of the wound neovessels, a critical process for infarct healing. Chemokine expression is also noted after a single brief ischemic insult in the absence of myocardial infarction, suggesting a potential role for a chemokine-induced inflammatory response in noninfarctive ischemic cardiomyopathy. Unlike cytokines, which have pleiotropic effects, chemokines have more specific cellular targets. Understanding of their role in myocardial infarction may allow us to design specific therapeutic strategies aiming at optimizing cardiac repair and preventing ventricular remodeling.

Therapeutic Angiogenesis by Gene Transfer in Critical Limb and Myocardial Ischemia

Cardiovascular atherosclerotic diseases remain leading causes of morbidity and mortality in the world. Despite the significant progress that has been made in the management of these diseases using medical, surgical and percutaneous therapies over the last three decades, there remains a significant population of patients who are not optimal candidates for surgical or percutaneous revascularization. Substantial research has focused on the administration of angiogenic growth factors, either as recombinant protein or by gene transfer, to promote the development of supplemental collateral blood vessels that will constitute endogenous bypass conduits around occluded native arteries, a strategy termed “therapeutic angiogenesis”. While many cytokines have angiogenic activity, the best studied both in animal models and clinical trials are vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). This review will discuss gene transfer strategies for therapeutic angiogenesis in critical limb and myocardial ischemia.