Considerations to the policy of future clinical therapeutic trials in DMD

In spite of rapidly increasing insight into the molecular basis of neuromuscular diseases, treatment still relies on convention and clinical studies. Experience with a multicentre double blind treatment study in Duchenne muscular dystrophy and with consecutive steroid treatment documentation for up to 8 years enables us to identify a series of crucial points on which to focus while planning such clinical trials. The most important seem to be: a carefully structured, detailed study, clear-cut aims and objectives, expertise of investigators, sufficient training of examiners, and careful monitoring. If patients with neuromuscular diseases are treated outside structured studies, their course should be monitored comparably. Examples of the impact of such documentation are available from the ongoing German multicentre trial on the treatment of Duchenne muscular dystrophy.     

Prospect of therapeutic approaches to tauopathies

Alois Alzheimer described the concurrence of two conspicuous proteinacious aggregates in 1906. Today it is clear that the two types of protein aggregates are fundamentally different. One consists of a short fragment (Abeta peptide) of a membrane protein APP and is found mainly outside of cells and the other is formed from a biochemically modified cytoskeleton-associated protein known as tau. The latter is found exclusively inside cells. Aggregated tau in all tauopathies including AD is abnormally modified by the excess incorporation of chemical groups called phosphates (hyperphosphorylation), and the appearance of this biochemical change coincides with the onset all tauopathies, suggesting that it is both a necessary and sufficient cause for such diseases. Data indicate that the basis for tau hyperphosphorylation is the dysregulation of key enzymes known as kinases. These enzymes are therapeutic targets for AD and other neurodegenerative diseases, which feature pathological tau structures in brain     

DMD(mdx3Cv) and DMD(mdx4Cv) dystrophin mutations in mice: rapid polymerase chain reaction genotyping

We devised non-radioactive PCR assays for the DMD(mdx3Cv) and DMD(mdx4Cv) mouse dystrophin point mutations, in which mutant and wild type reactions electrophoresed separately diagnose whether the DNA carries the mutant, wild type, or both alleles. This simple and reliable assay facilitates the use of these mutant mouse models, which have an extended inflammatory phase (DMD(mdx3Cv)), less reversion to wild type (DMD(mdx4Cv)), and reduced expression of dystrophin mRNAs arising from internal promoter usage than the DMD(mdx) mouse. The PCR assays described facilitate the use of the DMD(mdx3Cv) and DMD(mdx4Cv) mutant mouse models, when maintaining the mutations as heterozygotes, backcrossing into different inbred genetic backgrounds, or when crossing targeted mutations into these dystrophic backgrounds.     

Prospect of therapeutic approaches to tauopathies

Alois Alzheimer described the concurrence of two conspicuous proteinacious aggregates in 1906. Today it is clear that the two types of protein aggregates are fundamentally different. One consists of a short fragment (Aβ peptide) of a membrane protein APP and is found mainly outside of cells and the other is formed from a biochemically modified cytoskeleton-associated protein known as tau. The latter is found exclusively inside cells. Aggregated tau in all tauopathies including AD is abnormally modified by the excess incorporation of chemical groups called phosphates (hyperphosphorylation), and the appearance of this biochemical change coincides with the onset all tauopathies, suggesting that it is both a necessary and sufficient cause for such diseases. Data indicate that the basis for tau hyperphosphorylation is the dysregulation of key enzymes known as kinases. These enzymes are therapeutic targets for AD and other neurodegenerative diseases, which feature pathological tau structures in brain     

The milder phenotype of the dystrophin gene double deletions

OBJECTIVES: This study aimed to examine the genotypephenotype correlation in Duchenne muscular dystrophy (MD) patients with double deletion (Ddel) mutations in comparison with those having single deletions (Sdel). MATERIALS AND METHODS: The study included 250 Duchenne/Becker MD male patients from whom the 10 Ddel patients were compared with 20 Sdel subjects of same age and disease durations. The patients were subjected to neurological examination including functional disability grading scale (FDGS), molecular analysis of the dystrophin gene and immunohistochemical studies of some muscle biopsies. RESULTS: The mean FDGS value in the Ddel group was lower than that in Sdel patients. The Ddel patients had partial expression of dystrophin in their skeletal muscles, while Sdel cases showed complete absence of the protein. CONCLUSION: Patients with double deletion mutations within the dystrophin gene have a milder phenotype than patients harboring single deletions at either major or minor hot spots of the gene.     

Two mutations in one dystrophin gene

Background and purposeDuchenne/Becker muscular dystrophies (DMD/BMD) lead to progressive irreversible muscle deterioration caused by recessive mutations in the dystrophin encoding gene (Xp21.1). Approximately 60% of mutations are deletions, 10% are duplications and the remaining 30% are point mutations. The aim of the study is to present the rare occurrence of two pathogenic mutations (deletions or duplications) in one allele of the dystrophin gene.Material and methodsDNA of patients from 1364 DMD/BMD families was tested. Two techniques – PCR-multiplex and multiplex ligation-dependent probe amplification – were used to search for mutations in the dystrophin gene.ResultsDeletion was detected in 648 families and duplication was found in 74 families (analysis in progress). In two families, presence of two mutations in one gene was documented – in the first family two deletions were found (exons 45–49 and 60–61), and in the second family two duplications were detected (exons 2–7 and 50–59). One of the deletions disrupted the reading frame, and the other deletion retained the reading frame. Both duplications also retained the reading frame of the gene but in both families the disease took a severe course (DMD). In the family with two duplications prenatal diagnosis was also carried out, and carriership of both mutations was discovered in the female fetus.ConclusionsIn the analyzed group of DMD/BMD families, the frequency of combined occurrence of two mutations in one gene was 2 per 722 (0.3%). The phenomenon of detected non-contiguous deletions and duplications is presented together with 31 similar cases published so far.     

DMD/BMD肌细胞抗肌营养不良蛋白免疫荧光组化研究

目的:研究Duchenne/Becker型肌营养不良症(DMD/BMD)患者肌细胞中抗肌营养不良蛋白(dystrophin)的表达及其诊断意义。方法:采用免疫荧光抗体染色技术对5例DMD,2例BMD肌细胞中抗肌营养不良蛋白进行检测,以2例正常人的肌细胞作为以照。结果:对照组肌细胞膜上染色阳性,胞核及胞浆呈阴性;DMD患者肌膜完全无显色;BMD患者染色弱阳性,可见沿肌细胞膜分布的间断斑片状荧光带。结论:抗肌营养不良蛋白缺乏或表达异常是DMD/BMD基本病理基础。应用免疫荧光抗体染色法检测抗肌营养不良蛋白,有助于DMD和BMD的确诊及鉴别诊断     

Evolving therapeutic approaches to treating acute ischemic stroke

Stroke contributes significantly to death, disability, and healthcare costs; however, recombinant tissue plasminogen activator (rt-PA) is the only approved thrombolytic therapy for acute ischemic stroke. One area of development for new ischemic stroke treatment options is focused on neuroprotection of viable tissue in the ischemic vascular bed. The ischemic penumbra is recognizable on MRI by decreased perfusion, in contrast to the core area of ischemia, which includes diffusion and perfusion abnormalities. Understanding the mechanisms of neuronal death, including the role of excitotoxic neurotransmitters, free radical production, and apoptotic pathways, is important in developing new therapies for stroke. This article reviews these causes and results of stroke, as well as current and future neuroprotective treatment options. Several compounds have shown neuroprotective effects in animal studies, but have failed to be effective in human clinical trials. Several promising therapeutic areas include targeting of free radicals, modulation of glutamatergic transmission, and membrane stabilization via ion channels.     

New therapeutic approaches to Parkinson's disease including neural transplants

Parkinson's disease (PD) is a common neurodegenerative disorder of the brain and typically presents with a disorder of movement. The core pathological event underlying the condition is the loss of the dopaminergic nigrostriatal pathway with the formation of alpha-synuclein positive Lewy bodies. As a result, drugs that target the degenerating dopaminergic network within the brain work well at least in the early stages of the disease. Unfortunately, with time these therapies fail and produce their own unique side-effect profile, and this, coupled with the more diffuse pathological and clinical findings in advancing disease, has led to a search for more effective therapies. In this review, the authors will briefly discuss the emerging new drug therapies in PD before concentrating on a more detailed discussion on the state of cell therapies to cure PD.     

Gene therapeutic approaches to the treatment of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative illness of unknown etiology that presently has no cure. Symptoms of this progressively debilitating disease include bradykinesia, resting tremor, rigidity, gait abnormalities, and postural instability that can be transiently alleviated via continued administration of the drug, -DOPA. However, following prolonged usage, the effectiveness of this clinical treatment substantially diminishes. To that end, novel therapies for amelioration of symptoms and/or permanent cure of PD need to be developed. The utility of gene transfer modalities for PD treatment holds tremendous promise, but gene therapy is yet unproven within the realm of the central nervous system. This discourse proposes possible disease targets and reviews the present standing of adenovirus-, adeno-associated virus-, herpes virus-, and non-virus-based gene transfer technologies in regard to how they have been applied in in vitro and in vivo models of PD. Identification of disease mechanisms, potential points of therapeutic intervention, and an understanding of presently utilized gene delivery vehicles will facilitate the development of potentially safe and efficacious modalities for therapy of PD.     

Current AQP research: therapeutic approaches to ischemic and hemorrhagic stroke

正The role of aquaporins(AQPs)in the formation of cerebral edema after stroke:Stroke can be classified into either ischemic or hemorrhagic based on their etiological mechanism.Cerebral edema development often accompanies both ischemic infarct and intracerebral hemorrhage(ICH).Cerebral edema is differentiated according to their underlying mechanism and time course:cytotoxic and vasogenic.     

New therapeutic approaches in glioblastomas

Current treatment of glioblastomas relies on surgical resection, radiotherapy and chemotherapy. However, the efficacy of these therapeutics is still limited and new therapeutic approaches based on the understanding of brain tumor biology are emerging. High expression of the EGF receptor by tumor cells, activation of the PI3K/Akt and the Ras/Raf pathways represent interesting targets for new selective drugs under development. The most promising drugs are currently antiangiogenic agents. This article reviews these emerging therapies currently under clinical trials in glioblastomas.     

Mitochondrial encephalomyopathies: therapeutic approaches

Therapy of mitochondrial encephalomyopathies (defined restrictively as defects of the mitochondrial respiratory chain) is woefully inadequate, despite great progress in our understanding of the molecular bases of these disorders. We review available and experimental therapeutic approaches, which fall into seven categories: (1) palliative therapy; (2) removal of noxious metabolites; (3) administration of artificial electron acceptors; (4) administration of metabolites and cofactors; (5) administration of oxygen radical scavengers; (6) gene therapy; and (7) genetic counselling. Progress in each of these approaches provides some glimmer of hope for the future, although much work remains to be done.     

New therapeutic approaches in glioblastomas

INTRODUCTION: Current treatment of glioblastomas relies on surgical resection, radiotherapy and chemotherapy. However, the efficacy of these therapeutics is still limited and new therapeutic approaches based on the understanding of brain tumor biology are emerging. STATE OF ART: High expression of the EGF receptor by tumor cells, activation of the PI3K/Akt and the Ras/Raf pathways represent interesting targets for new selective drugs under development. Proteases inhibitors and antiangiogenic agents are also under investigations in clinical trials. Perspectives. In addition, the recent development of convection-enhanced delivery technique allows the administration of drugs which do not cross the blood-brain-barrier, such as selective toxins or immunostimulating oligonucleotides. CONCLUSION: Though the results of clinical trials have been somewhat disappointing, using different drug combinations or drug-radiotherapy associations will probably enable an improvement in the prognosis for these patients in the future.     

A homologue of dystrophin is expressed at the blood vessel membrane of DMD and BMD patients: immunological evidence.

Muscles from Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD) patients were analysed using monoclonal and polyclonal antibodies raised against different regions of the dystrophin molecule. On blot, two of the antibodies detected a protein of Mr 400K in muscle extracts from all patients, including a BMD patient with a deletion which spanned more than 40% of the central rod domain of the Xp21 encoded dystrophin. Immunocytochemical labelling of tissue sections from the same patients showed that the same two antibodies labelled a protein at the surface membrane of smooth muscle fibers in blood vessels of both BMD and DMD muscles. Thus we have demonstrated a 400K blood vessel-associated protein, which is immunologically homologous with dystrophin, for at least two epitopes from the carboxy terminal and the central rod domains must be encoded by another gene than the dystrophin gene.