Alba Migliorato

VEGF overexpression via adeno-associated virus gene transfer promotes skeletal muscle regeneration and enhances muscle function in mdx mice

Vascular endothelial growth factor (VEGF) is a major regulator of physiological and pathological angiogenesis. Recently it was reported that the delivery of VEGF using recombinant adeno‐associated virus (rAAV) vectors reduces muscle damage and promotes muscle regeneration in different experimental models of muscle necrosis. We demonstrate that intramuscular administration of rAAV‐VEGF improved pathophysiology of the mdx mouse, a model of Duchenne muscular dystrophy (DMD). One month after injection, rAAV‐VEGF‐treated muscles showed augmented expression of VEGF and immu‐nolocalization of its receptor, VEGFR‐2. VEGF‐treated mdx mice showed increased forelimb strength and strength normalized to weight. Treatment reduced necrotic fibers area and increased regenerating fibers area with an augmented number of myoge‐nin‐positive satellite cells and myonuclei, and of developmental myosin heavy chain‐positive fibers. Only the regenerating area showed increased capillary density. This study provides novel evidence of a VEGF beneficial effect in mdx mice that is exerted mainly by a proregenerative and angiogenic effect. It opens new therapeutic prospectives in DMD and other types of muscular disorders.—Messina S., Mazzeo, A., Bitto, A., Aguennouz, M., Migliorato, A., De Pasquale M. G., Minutoli, L., Altavilla, D., Zentilin L., Giacca, M., Squadrito, F., Vita G. VEGF overexpression via adeno‐associated virus gene transfer promotes skeletal muscle regeneration and enhances muscle function in mdx mice. FASEB J. 21, 3737–3746 (2007)

Simvastatin enhances VEGF production and ameliorates impaired wound healing in experimental diabetes

Statins have different effects beyond cholesterol reduction and stimulate angiogenesis. We investigated the effect of simvastatin in diabetes-related healing defects. An incisional skin wound model produced on the back of female diabetic mice (db(+)/db(+)) and their normoglycemic littermates (db(+)/(+)m) was used. Animals were treated daily either with simvastatin (5 mg/(kgi.p.)) or vehicle. Mice were killed on different days (3, 6 and 12 after skin injury) for measurement of vascular endothelial growth factor (VEGF) mRNA and protein expression, to assess histologically the healing process and to evaluate wound breaking strength and angiogenesis by CD31 immunostaining. Simvastatin administration in diabetic mice increased VEGF mRNA (simvastatin=4.8+/-0.6n-fold/beta-actin; vehicle=2.3+/-0.4n-fold/beta-actin) and protein expression (simvastatin=5+/-0.7 integrated intensity; vehicle=2.2+/-0.3 integrated intensity) and enhanced nitric oxide wound content at day 6. Additionally, the statin augmented breaking strength and PECAM-1 immunostaining at day 12. Finally, simvastatin administration restored the impaired wound healing process in diabetic mice. Similar results were obtained in normoglycaemic mice. Passive immunization with anti-VEGF antibody (10 microg/mouse) completely abrogated the beneficial effects of simvastatin on healing in diabetic mice. Simvastatin has potential application in diabetes-related wound healing disorders.

Flavocoxid counteracts muscle necrosis and improves functional properties in mdx mice: a comparison study with methylprednisolone.

Muscle degeneration in dystrophic muscle is exacerbated by the endogenous inflammatory response and increased oxidative stress. A key role is played by nuclear factor(NF)-kappaB. We showed that NF-kappaB inhibition through compounds with also antioxidant properties has beneficial effects in mdx mice, the murine model of Duchenne muscular dystrophy (DMD), but these drugs are not available for clinical studies. We evaluated whether flavocoxid, a mixed flavonoid extract with anti-inflammatory, antioxidant and NF-kappaB inhibiting properties, has beneficial effects in mdx mice in comparison with methylprednisolone, the gold standard treatment for DMD patients. Five-week-old mdx mice were treated for 5 weeks with flavocoxid, methylprednisolone or vehicle. The evaluation of in vivo and ex vivo functional properties and morphological parameters was performed. Serum samples were assayed for oxidative stress markers, creatine-kinase (CK) and leukotriene B-4. Cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), tumor necrosis factor-alpha, p-38, JNK1 expression was evaluated in muscle by western blot analysis. NF-kappaB binding activity was investigated by electrophoresis mobility shift assay. The administration of flavocoxid: (1) ameliorated functional properties in vivo and ex vivo; (2) reduced CK; (3) reduced the expression of oxidative stress markers and of inflammatory mediators; (4) inhibited NF-kappaB and mitogen-activated protein kinases (MAPKs) signal pathways; (5) reduced muscle necrosis and enhanced regeneration. Our results highlight the detrimental effects of oxidative stress and NF-kappaB, MAPKs and COX/5-LOX pathways in the dystrophic process and show that flavocoxid is more effective in mdx mice than methylprednisolone.

Polydeoxyribonucleotide (PDRN) restores blood flow in an experimental model of peripheral artery occlusive disease

OBJECTIVE This study investigated whether polydeoxyribonucleotide (PDRN) may be efficacious in the treatment of peripheral artery occlusive diseases, which are a major cause of morbidity in Western countries and still lack standardized treatment. METHODS We investigated the effects of PDRN, a mixture of deoxyribonucleotides, in an experimental model of hind limb ischemia (HLI) in rats to stimulate vascular endothelial growth factor (VEGF)-A production and to avoid critical ischemia. The femoral artery was excised to induce HLI. Sham-operated on rats (sham HLI) were used as controls. Animals were treated daily with intraperitoneal PDRN (8 mg/kg) or its vehicle. Animals were euthanized at day 7, 14, and 21 after the evaluation of blood flow by laser Doppler. Dissected muscles were used to measure VEGF-A messenger RNA (mRNA) and protein expression, to evaluate edema, and to assess histologic damage. RESULTS Administration of PDRN dramatically increased VEGF mRNA throughout the study (day 14: HLI, 7 +/- 2.2 n-fold/beta-actin; HLI + PDRN, 13.3 +/- 3.8 n-fold/beta-actin; P < .0001) and protein expression (HLI, 11 +/- 3.4 integrated intensity; HLI + PDRN, 16 +/- 3.8 integrated intensity; P < .0001). The compound stimulated revascularization, as confirmed by blood flow restoration (P < .005 vs HLI + vehicle), and blunted the histologic damage and the degree of edema. PDRN did not modify VEGF-A expression and blood flow in sham HLI animals. Furthermore, the concomitant administration of 3,7-dimethyl-1-propargilxanthine (DMPX), a selective adenosine A(2A) receptor antagonist, abolished the positive effects of PDRN, confirming that PDRN acts through this receptor. CONCLUSION These results led us to hypothesize a role for PDRN in treating peripheral artery occlusive diseases.

Asymptomatic hyperCKemia in a case of Danon disease due to a missense mutation in Lamp-2 gene

Primary lysosome-associated membrane protein-2 (LAMP-2) deficiency is an X-linked disease, characterized by the clinical triad of cardiomyopathy, vacuolar myopathy and mental retardation, previously known as Danon disease. Mutations of lamp-2 gene have been reported so far in about 20 patients, one of whom was Italian. We describe a new Italian case with persistent hyperCKemia, exercise intolerance and hypertrophic cardiomyopathy but with no muscle weakness or mental impairment. Muscle biopsy revealed a vacuolar myopathy with mild glycogen storage, and immunohistochemical studies detected LAMP-2 deficiency. A new nucleotide substitution (T961C) on exon 8 of lamp-2 gene was identified as responsible for the protein deficiency. This is the first missense mutation so far described. LAMP-2 deficiency should be considered as a cause of recurrent hyperCKemia and hypertrophic cardiomyopathy.

Expression of cytoskeleton proteins in central core disease

Despite advances in genetics the pathogenesis of central core disease (CCD) is still unknown. We studied muscles from 5 CCD patients by immunocytochemistry using monoclonal antibodies against various cytoskeletal proteins (dystrophin, spectrin, vinculin, desmin, vimentin, myosin heavy chain (MHC) of developmental, neonatal, adult slow and fast types). Dystrophin, spectrin and vinculin immunoreactivity was localized only at sarcolemma as in normal muscle. Vimentin was not present in myofibers. Only sporadic fibers were positive for developmental and neonatal MHC isoforms in adult CCD muscles. A 4-month-old patient had 5% of neonatal MHC-immunoreactive fibers, a finding similar to that of age-matched normal muscle. Desmin intermediate filaments were overexpressed in many core-fibers in extra-core regions, reduced or absent at cores, and greatly increased at the periphery of some cores. Moreover, irregular desmin-positive spots were seen within some cores. On the contrary, in neurogenic muscle atrophy patients, target lesions had increased desmin. These features indicate a possible role of desmin in the pathogenesis of cores, although we do not know if primary or secondary. In addition, they suggest that: (i) cores and targets may be manifestations of different processes; (ii) it is likely that core-fibers are not denervated fibers.

The soy isoflavone genistein blunts nuclear factor kappa-B, MAPKs and TNF-α activation and ameliorates muscle function and morphology in mdx mice

Several lines of evidence suggest a detrimental role of the nuclear factor-κB (NF-κB) activation in the dystrophic process. We showed in previous studies that its inhibition through drugs with antioxidant properties, have beneficial effects in mdx mice. We tested whether genistein, a well-known isoflavone, inhibitor of NF-κB, MAPK and TNF-α and readily available for clinical use, could have a beneficial effect in mdx mice in comparison with methylprednisolone, the gold standard treatment for DMD patients. Five-week old mdx mice received for five weeks: genistein (daily or 3-times/week), methylprednisolone or vehicle. Genistein treatment: (1) increased forelimb strength and strength normalized to weight; (2) reduced serum creatine-kinase levels; (3) reduced markers of oxidative stress; (4) reduced muscle necrosis and enhanced regeneration. The positive results were more evident with the daily administration of genistein and were comparable to the effect of corticosteroids. Our data support the novel hypothesis that, as other more specific therapeutic approaches are still under development, this soy-derived compound is a promising option to be further investigated in dystrophic process.

Immunohistochemical analysis of human skeletal muscle AMP deaminase deficiency. Evidence of a correlation between the muscle HPRG content and the level of the residual AMP deaminase activity

We have previously described that, in healthy human skeletal muscle, an anti-histidine-proline-rich-glycoprotein (HPRG) antibody selectively binds to type IIB fibers that are well known to contain the highest level of AMP deaminase (AMPD) activity, suggesting an association of the HPRG-like protein to the enzyme isoform M. The present paper reports an immunohistochemical study performed on human skeletal muscle biopsies from patients with AMPD deficiency and carried out utilizing both the anti-HPRG antibody and an anti-AMPD antibody specific for the isoform M. A correlation between the muscle content of the HPRG-like protein and the level of AMPD activity was demonstrated. In the specimens from patients with Acquired AMPD deficiency the HPRG-immunoreactivity was less intense than that shown by the control subjects and was related to the residual AMPD activity. The patients affected by Primary and Coincidental AMPD deficiency, which were characterized by an absence of enzyme activity and AMPD immunoreactivity, showed the lowest HPRG immunoreactivity that was clearly detectable by Western blot analysis, but not by immunohistochemistry. The interpretation of the significance of these observations suggests a physiological mutual dependence between skeletal muscle HPRG and AMPD polypeptides with regard to their stability.

Sporadic late-onset nemaline myopathy in a woman with multiple myeloma successfully treated with lenalidomide/dexamethasone

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Dp116, talin, vinculin and vimentin immunoreactivities following nerve transection.

THE time course of the expression of Dp116, talin, vinculin and vimentin in rat sciatic nerve was investigated after experimental transection. Dp116 was still found at 5 days after experiment in some degenerating myelinated fibers of both proximal and distal stumps. The findings are consistent with the known preservation of electrical excitability of the distal nerve in the first days after injury. Some regenerating nerve fibers into the neuroma also expressed Dp116 at 25 and 40 days after nerve transection. Talin and vinculin markedly and diffusely immunostained the neuroma. Talin in the distal stump and vimentin in both proximal and distal stumps were found decreased during the time course of the experiment. Vinculin binding increased in the distal stump, due to a real overexpression or simply to a cross-reaction to degeneration products.