Association of vitamin D status with multiple sclerosis in a case-control study from Morocco.

BACKGROUND: Growing evidence suggests that hypovitaminosis D contributes to the pathogenesis of multiple sclerosis (MS). OBJECTIVE: This study aimed to evaluate whether vitamin D levels are associated with having MS and some of its characteristics in the Moroccan population. METHODS: Using liquid chromatography-tandem mass spectrometry, the 25(OH)D3 metabolite was measured to quantify vitamin D serum levels (DSLs) in 113 patients with MS and 146 healthy controls matched for gender and age. DSLs were then compared between patients and controls, with correlations sought between DSLs and gender, age at onset, disease duration, MS type, degree of disability (EDSS score) and disease severity (MSSS) in patients. RESULTS: Hypovitaminosis D (DSL<30ng/mL) was observed in 97.3% of MS patients and in 98.6% of controls. Although the mean DSL was slightly lower in patients (11.69±6.97ng/mL) than in controls (12.98±6.58ng/mL), there was no significant association between DSL and MS status (P=0.131). Similarly, among patients, no apparent association was found between DSL and MS type (P=0.214), EDSS score (P=0.076) or MSSS (P=0.772). CONCLUSION: Our study suggests that DSL is not associated with having MS nor with MS type, degree of disability or disease severity in the Moroccan population. On the other hand, DSL was lower in women and decreased with age.

[Vascular calcification in pseudoxanthoma elasticum in children]. / Calcifications vasculaires dans le pseudoxanthome élastique chez l'enfant.

INTRODUCTION: Vascular calcifications are associated with several diseases that affect vascular connective tissue and skin and cause considerable morbidity and mortality. The prototype of these conditions is pseudoxanthoma elasticum. We report, in this study, 4 pediatric cases of vascular calcifications diagnosed as elastic pseudoxanthoma. OBSERVATIONS: These 4 children were 2-11 years old and presented variable clinical features. Vascular involvement and arterial hypertension was observed in all patients, skin involvement in 2 cases, gastrointestinal involvement in 2 cases, neurological impairment in one case, and cardiac involvement in one case. Demonstration of ABCC6 gene mutations provided diagnostic confirmation in all cases. CONCLUSION: Pseudoxanthoma elasticum is a rare genetic disease, which can lead to many complications. Appropriate knowledge and early diagnosis are essential.

[Pseudoxanthoma elasticum: A rare cause of gastrointestinal bleeding in children]. / Pseudo-xanthome élastique : une cause rare d'hémorragies digestives chez l'enfant.

INTRODUCTION: Pseudoxanthoma elasticum (PXE) is a rare autosomal recessive connective tissue disorder, characterized by calcification and progressive fragmentation of elastic fibers. Gastrointestinal lesions are rare in children and may be responsible for serious complications. This article reports two pediatric cases of PXE revealed by gastrointestinal bleeding. CASE REPORTS: An 11-year-old boy and a 12-year-old girl were hospitalized for gastrointestinal bleeding. Digestive endoscopy showed hemorrhagic gastroenteritis bulbitis in the first case and it was normal in the second. Abdominal ultrasound showed diffuse linear calcifications in both cases. The diagnosis of PXE was retained based on the presence of vascular disease in both patients, a skin lesion in the girl, and an ocular lesion in the boy. The genetic study confirmed the diagnosis of PXE identifying two ABCC6 mutations in the composite state in the boy: the c.2263G> A (p.G755R) mutation on exon 18 and the c.3421C> T (pR1141X) mutation on exon 24 and the 4021G> A (R1164Q) mutation in the homozygous state of ABCC6 exon 24 in the girl. CONCLUSION: Digestive manifestations are unusual ; however, pseudoxanthoma elasticum should be considered in all cases of gastrointestinal bleeding for no apparent reason. Early diagnosis allows prevention and measures to control the risk factors and limit the progression of complications.

PCR-based assay to detect sheeppox virus in ocular, nasal, and rectal swabs from infected Moroccan sheep.

Sheeppox is now enzootic in Morocco. The development of a reliable method for rapid diagnosis of the disease is a central part of any control strategy. The aim of this study is to determine the diagnostic value of a variety of clinical samples such as ovine nasal, ocular or rectal swabs for the detection of sheeppox virus (SPPV) by qualitative conventional polymerase chain reaction (PCR), using a single pair of primers targeting the inverted terminal repeats of the SPPV InS-1 strain, a virulent field isolate. Swab and blood samples were collected from forty animals naturally infected with SPPV who had clinical signs of sheeppox. All animals tested PCR-positive for SPPV. Positive results were obtained infrequently with blood samples, whereas swab samples from at least two sites (nasal, ocular, rectal) were positive per evaluated animal. These results indicate that swab samples are suitable for quantitative molecular SPPV diagnosis. PCR product sequences obtained from all types of sheep samples proved to be identical to the corresponding regions of sheeppox virus strain Romania 65.

Tubulyzine, a novel tri-substituted triazine, prevents the early cell death of transplanted myogenic cells and improves transplantation success.

Myoblast transplantation (MT) is a potential therapeutic approach for several muscular dystrophies. A major limiting factor is that only a low percentage of the transplanted myoblasts survives the procedure. Recent advances regarding how and when the myoblasts die indicate that events preceding actual tissue implantation and during the first days after the transplantation are crucial. Myoseverin, a recently identified tri-substituted purine, was shown to induce in vitro the fission of multinucleated myotubes and affect the expression of a variety of growth factors, and immunomodulation, extracellular matrix-remodeling, and stress response genes. Since the effects of myoseverin are consistent with the activation of pathways involved in wound healing and tissue regeneration, we have investigated whether pretreatment and co-injection of myoblasts with Tubulyzine (microtubule lysing triazine), an optimized myoseverin-like molecule recently identified from a triazine library, could reduce myoblast cell death following their transplantation and consequently improves the success of myoblast transplantation. In vitro, using annexin-V labeling, we showed that Tubulyzine (5 microM) prevents normal myoblasts from apoptosis induced by staurosporine (1 microM). In vivo, the pretreatment and co-injection of immortal and normal myoblasts with Tubulyzine reduced significantly cell death (assessed by the radio-labeled thymidine of donor DNA) and increased survival of myoblasts transplanted in Tibialis anterior (TA) muscles of mdx mice, thus giving rise to more hybrid myofibers compared to transplanted untreated cells. Our results suggest that Tubulyzine can be used as an in vivo survival factor to improve the myoblast-mediated gene transfer approach.

Tumor necrosis factor-alpha (TNF-alpha) stimulates chemotactic response in mouse myogenic cells.

Migration of transplanted myogenic cells occurs during both embryogenesis and regeneration of skeletal muscles and is important for successful myoblast transplantation, but little is known about factors that promote chemotaxis of these cells. Tumor necrosis factor-alpha (TNF-alpha) is known to induce chemotactic effect on several cell types. In this study, we investigated its influence on the in vitro and in vivo motility of C2C12 and primary myoblasts. In the in vitro test performed in the blind-well Boyden chambers, we showed that TNF-alpha (50-400 U/ml) significantly enhanced the ability of myogenic cells to migrate. The dose-response curve for this factor was bell shaped, with maximum activity in the 200 U/ml range. In the in vivo test, intramuscular administration of TNF-alpha was performed by an Alzet pump connected to a perforated polyethylene microtube inserted in the tibialis anterior (TA) of CD1 mice. In these experiments, myoblasts were injected under the muscle epimysium. The recipient mice were immunosuppressed with FK506. Our results showed that, 5 days after myoblast transplantation, cells migrated further in the muscles infused with TNF-alpha than in the muscles not exposed to TNF-alpha. TNF-alpha not only has a chemotactic activity but may also modify cell migration via its action on matrix metalloproteinase (MMP) expression. The proteolytic activities of the MMPs secreted in the muscles were thus also assessed by gelatin zymography. The results showed an increased of MMP-2 and MMP-9 transcripts in the TNF-alpha-infused muscles injected with myogenic cells. Myoblast migration during transplantation may be enhanced by overlapping gradients of several effector molecules such as TNF-alpha, interferon-gamma (INF-gamma), and interleukins, released at the site of muscle injury. We propose that TNF-alpha may promote myoblast migration directly through chemotactic activity and indirectly by enhancing MMP activity at the site of muscle injury.

The urokinase plasminogen activator: an interesting way to improve myoblast migration following their transplantation.

Muscle cell migration plays an important role in the incorporation of transplanted myoblasts in muscle fibers. Understanding the mechanisms underlying the high migration capacity of the C(2)C(12) myoblast cell line may help to develop approaches to improve the migration of normal myoblasts and consequently to increase their participation to the host myofiber regeneration. We have previously shown that matrix metalloproteinases are implicated in the in vivo migration of C(2)C(12). Here, we studied the role of urokinase plasminogen activator (uPA) in this process. The expression of uPA mRNA and the enzymatic activity of uPA were studied in both normal myoblasts and the C(2)C(12) myoblast cell line. Reverse transcriptase polymerase chain reaction analysis showed that uPA mRNA was more strongly expressed in C(2)C(12) cells than in normal myoblasts. The enzymatic activity of secreted uPA analyzed by casein zymography is higher in medium conditioned by C(2)C(12) cells than in medium conditioned by normal myoblasts. Using our previously described microtube technique to assess in vivo cell migration, we showed that uPA is implicated in the in vivo migration of C(2)C(12) cells since this migration was abrogated in the presence of aprotinin (a general serine protease inhibitor) or amiloride (a uPA-specific inhibitor). We, therefore, hypothesized that increasing endogenous uPA expression by normal myoblasts may improve their migration capacity. Since an accumulating body of evidence has shown that growth factors regulate expression of uPA in a wide range of cells, we treated normal myoblasts with several growth factors alone or in combination with components of the extracellular matrix (ECM). All stimulants tested showed a minimal to strong effect on uPA enzymatic activity as assayed by zymography analysis. The positive effect of basic fibroblast growth factor (bFGF) on uPA enzymatic activity was slightly potentiated in the presence of fibronectin. Moreover, the pretreatment and coinjection of mouse myoblasts with bFGF alone or in combination with fibronectin improved significantly their in vivo migration throughout the tibialis anterior muscle of mdx mice. These results suggest that increasing uPA expression by an appropriate combination of growth factors and ECM components constitutes a possible approach to improving the migration of myogenic cells after transplantation.

Intramuscular migration of myoblasts transplanted after muscle pretreatment with metalloproteinases.

The effect of pretreatments of host muscles with metalloproteinases (MMPs) or with notexin on the migration of transplanted myoblasts was investigated. Transgenic TnILacZ mice in which the beta-galactosidase gene is under the control of a quail fast skeletal troponin I gene promoter were used as donors. A polyethylene microtube with four perforations was inserted in the tibialis anterior (TA) of CD1 mice. Both pretreatment substances and cells were slowly injected through that microtube. Muscles were pretreated 2 days before myoblast injection either with a mixture of collagenase, matrilysin, and notexin or with only collagenase and matrilysin or only notexin. As control for our experiments, TnILacZ and C2C12 myoblasts were also injected in TA muscles not pretreated. Comparison of short and long-term myoblast radial migration was performed using a dye (PKH26) and X-gal staining, respectively. The recipient mice were immunosuppressed with FK506. Two days after myoblast transplantation, the cell movement in muscles pretreated with collagenase, matrilysin, and notexin was slightly greater than in muscles pretreated only with collagenase and matrilysin but was about twice that observed in muscles treated with notexin alone. Almost no radial migration of TnILacZ myoblasts was observed in untreated muscles. The C2C12 myoblasts showed a four-to fivefold higher migration capacity than TnILacZ myoblasts. At 15 days after TnILacZ myoblast transplantation, the farthest positive beta-gal muscle fibers show a two- to threefold extension of the initial migration observed at 2 days, demonstrating the ability of myoblasts to continue the migration following all pretreatments and even in the untreated muscles. In addition, more muscle fibers expressed the beta-gal reporter gene in muscles pretreated only with MMPs. Our results clearly demonstrate that muscle pretreatments with MMPs increase myoblast migration and fusion with host muscle fibers after transplantation and that the C2C12 cell line producing MMPs has a higher migratory capacity.

In vivo migration of transplanted myoblasts requires matrix metalloproteinase activity.

Muscle cell migration and extracellular matrix remodeling are essential aspects of muscle development and regeneration. In this study, using a new technique to assess in vivo myoblast migration, we have confirmed previous results showing that the C(2)C(12) myoblast cell line exhibits a higher migratory capacity than primary myoblasts. To test the hypothesis that matrix metalloproteinases (MMPs) are required for the migration of C(2)C(12) myoblasts, we determined whether a synthetic metalloproteinase inhibitor, BB94 (Batimastat), inhibited this process in vivo. Pretreatment with BB94 for 3 days decreased the C(2)C(12) migration at 2 days after cell injection. Since MMP expression is thus necessary for myoblast migration, we have undertaken the identification and characterization of the MMPs expressed by the C(2)C(12) cell line. An RT-PCR assay was used to determine the pattern of MMP mRNA expression by the C(2)C(12) cell line. The proteolytic activities of the MMPs secreted in the culture medium were also assessed by gelatin zymography. The results showed that MMP2 (gelatinase A, 72-kDa type IV collagenase) and MT1-MMP transcripts were expressed by this cell line; however, only MMP2 was secreted and was able to be activated in the extracellular environment. This cell line failed to express MMP9 (gelatinase B, 92-kDa type IV collagenase), stromelysine 2, or stromelysine 3. Our observation that the membrane type MMP (MT1-MMP) transcript is also expressed by the C(2)C(12) suggests that the MMP2 proform (pro-MMP2), may be activated by the MT1-MMP. This possibility is supported by our observation that the pretreatment of C(2)C(12) with concanavalin A (which is known to induce the expression of MT1-MMP) resulted in the processing of pro-MMP2 to its mature form, in a dose-dependent manner. Overexpression and activation of MMP2 in normal myoblasts showed significant increased migration of mouse myoblasts in vivo. Our finding that MMP2 and MT1-MMP gene are coexpressed by C(2)C(12) myoblasts could account for the high migratory capacity of C(2)C(12). Together these results supported the importance of MMP2 and its activation by MT1-MMP for myoblast migration.

Pituitary adenylate cyclase-activating polypeptide induces expression of corticosteroid-binding globulin in cultured fetal hepatocytes: synergy with tri-iodothyronine.

The purpose of the present study was to determine whether functional receptors for pituitary adenylate cyclase-activating polypeptide (PACAP) are expressed in cultured rat fetal hepatocytes and eventually play a role in regulating gene expression of corticosteroid-binding globulin (CBG). We found PACAP38 and PACAP27 to elevate cAMP levels in hepatocytes in a dose-dependent manner, with a plateau being achieved at 10 nM and EC50 values of about 0.5-1 nM. PACAP failed to alter the turnover of inositol phosphates, whereas PACAP and VIP stimulated cAMP accumulation in an equipotent manner, suggesting the presence in these cells of type II receptor isoforms. As revealed by measurements of both CBG mRNA levels and concentrations of binding sites, long-term treatment of fetal cells with 10 nM PACAP, although resulting in partial desensitization of peptide-induced cAMP accumulation, caused a significant 3-fold elevation in CBG synthesis. This stimulatory influence of PACAP was mimicked by the cell permeant N6,2'-O-dibutyryladenosine 3',5'-phosphate (dbcAMP). Treatment of hepatocytes with tri-iodothyronine (T3) enhanced CBG expression and, most interestingly, appeared to synergize with PACAP to elicit a 2-3-fold amplification of CBG synthesis. This study thus provides first evidence for the up-regulation by PACAP and cAMP of CBG expression in fetal hepatocytes and for T3's playing a synergistic role in enhancing PACAP-induced synthesis of the binder.