Lack of association between FokI polymorphism in vitamin D receptor gene (VDR) & type 2 diabetes mellitus in the Tunisian population.

BACKGROUND & OBJECTIVES: The impact of several environmental and genetic factors on diabetes is well documented. Though the association between the vitamin D receptor (VDR) gene polymorphisms and type 2 diabetes mellitus (T2DM) has been analyzed in different ethnic groups, the results have been inconsistent. The aim of this study was to evaluate the possible association between VDR FokI polymorphism and genetic susceptibility to T2DM in Tunisian population. METHODS: A total of 439 unrelated patients with T2DM and 302 healthy controls were included in the study. Genomic DNA was extracted from blood and genotyped for the single nucleotide polymorphism (SNP) of FokI (T/C: (rs2228570) by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: The genotype distribution and the relative allelic frequencies for the FokI polymorphism were not significantly different between T2DM and controls: in T2DM patients the frequencies of the CC, CT, and TT genotypes were 52.6, 41.0, and 6.1 per cent, respectively, and in controls the genotype frequencies were 55.6, 38.7, and 5.6 per cent, respectively. In our study, the TT genotype of the FokI polymorphism was not associated with T2DM (OR =1.19, 95% CI 0.63 - 2.25, P=0.577). INTERPRETATION & CONCLUSIONS: Our study showed no significant association of the FokI polymorphism in the vitamin D receptor gene with type 2 diabetes mellitus in Tunisian population.

Inflammations mediators and circulating levels of matrix metalloproteinases: Biomarkers of diabetes in Tunisians metabolic syndrome patients.

AIMS: This study investigates the relationships between matrix metalloproteinases, inflammations mediators and type 2 diabetes mellitus in Tunisians metabolic syndrome (Mets) patients. METHODS: The study has included 239 MetS patients and 247 controls. Mets was defined according to the NCEP-ATPIII report. Mets patients were also divided into two categories: 29 MetS non-diabetics and 210 MetS diabetics. Dysglycemia markers, matrix metalloproteinase-9 (MMP-9), Tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), tumor necrosis factor α (TNF-α), C-reactive protein (CRP) levels and White Blood Cells (WBC) counts were determined in patients and controls. RESULTS: In our study, the level of inflammatory markers WBC, TNF-α and matrix metalloproteinases (MMP-8 and MMP-9) were significantly higher in diabetic patients with MetS, as compared with non-diabetic MetS patients. Inflammation mediators and MMP-9 were significantly associated with many clinical characteristics of MetS. The use of ROC "Receiver Operating Characteristic" analysis revealed the impact of TNF alpha on diabetes patients with MetS. In fact TNF alpha was found as a sensitive parameter in these patients with a sensitivity of 85%. CONCLUSION: Inflammation, matrix metalloproteinases and dysglycemia markers are not expressed in isolation but rather concurrently and are continuously interacting with each other, in MetS and diabetics patients. These markers fit with an early stage of cardiovascular disease (CVD); and measuring them could improve the risk evaluation, an early diagnosis, and the prognosis of CVD.

Bone Mineral Density in Sheehan's Syndrome; Prevalence of Low Bone Mass and Associated Factors.

Hypopituitarism is a known cause of bone mineral loss. This study aimed to evaluate the frequency of osteopenia and osteoporosis in patients with Sheehan's syndrome (SS) and to determine the risk factors. This is a retrospective study of 60 cases of SS that have had a bone mineral density (BMD) measurement. Clinical, biological, and therapeutic data were collected. The parameters of osteodensitometry at the femoral neck and the lumbar spine of 60 patients with SS were compared with those of 60 age-, height-, and weight-matched control women. The mean age at BMD measurement was 49.4 ± 9.9 yr (range: 25-76 yr). The mean duration of SS was 19.3 ± 8.5 yr (range: 3-41 yr). All patients had corticotropin deficiency and were treated with hydrocortisone at a mean daily dose of 26.3 ± 4.1 mg. Fifty-seven patients (95%) had thyrotropin deficiency and were treated with thyroxine at a mean daily dose of 124.3 ± 47.4 µg. Thirty-five of the 49 patients, aged less than 50 yr at diagnosis and having gonadotropin deficiency (71.4%), had estrogen-progesterone substitution. Osteopenia was present in 25 patients (41.7%) and osteoporosis in 21 (35.0%). The BMD was significantly lower in the group with SS than in the control group (p < 0.001). The odds ratio of osteopenia-osteoporosis was 3.1 (95% confidence interval: 1.4-6.8) at the femoral neck and 3.7 (95% confidence interval: 1.7-7.8) at the lumbar spine. The lumbar spine was more frequently affected by low bone mineral mass (p < 0.05). The duration of the disease and the daily dose of hydrocortisone were independently and inversely associated with BMD at the femoral neck. The daily dose of thyroxine was independently and inversely associated with BMD at the lumbar spine. Estrogen-progesterone replacement therapy was not associated with BMD. Low bone mineral mass was very common in patients with SS. The lumbar spine was more frequently affected. The duration of the disease and the doses of hydrocortisone and thyroxine were involved in bone mineral loss.

The Gly482Ser polymorphism of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is associated with type 2 diabetes in Tunisian population.

BACKGROUND AND AIMS: Peroxisome proliferator-activated receptor-γ co-activator-1α (PGC-1α) is a transcriptional co-activator involved in adaptive thermogenesis, skeletal muscle metabolism, fatty acid oxidation, and gluconeogenesis. Several studies have suggested that the common PGC-1α polymorphism Gly482Ser (rs8192678) may be associated with risk of type 2 diabetes (T2D), with conflicting results. The aim of this study was to analyze whether the Gly482Ser variant is a risk factor for development of T2D in Tunisian population. METHODS: In a case-control study 487 unrelated patients with type 2 diabetes and 402 apparently healthy controls were recruited from January 2008 to August 2010. The Gly482Ser polymorphism was determined by PCR-RFLP analysis. RESULTS: A significant difference in genotypes distribution was observed between patients (Gly/Gly: 34.1%; Gly/Ser: 47.1%; Ser/Ser: 18.5%) and controls (Gly/Gly: 43.8%; Gly/Ser: 42.3%; Ser/Ser: 13.9%) (χ(2)=9.44, p=0.009). The T2D patient group showed a significant higher frequency of the Ser allele compared to the controls (43% vs. 34%; OR: 1.35, 95% [CI]: 1.11-1.65, p=0.002). The association between the Gly482Ser polymorphism and T2D remained significant after adjustment for other well-established cardiovascular risk factors. CONCLUSIONS: In the current study, a significant and independent association between the Gly482Ser polymorphism (rs8192678) of the PGC-1α gene and T2D in the Tunisian population was found.

Tumor necrosis factor-α (TNF-α) -863C/A promoter polymorphism is associated with type 2 diabetes in Tunisian population.

AIMS: Tumor necrosis factor α (TNFα) plays a key role in orchestrating the complex events involved in inflammation and immunity. Accordingly, TNF α has been implicated in a wide range of autoimmune and infectious diseases, but also in conditions such as obesity and insulin resistance. The aim of the present study was to investigate the association between the -863C/A polymorphism in the promoter of the TNFα gene and type 2 diabetes in the Tunisian population. METHODS: The polymorphism -863C/A in the TNFα gene was determined in 211 type 2 diabetes patients and 345 healthy controls using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis. RESULTS: A significant difference in genotype distribution and allele frequency was observed between patients and controls. Patients with type 2 diabetes had significantly higher frequency of the CA+AA genotypes compared to controls [35.5% vs. 22.3%; OR (95%CI), 1.91 (1.31-2.8); p=0.001]. The type 2 diabetes patient group showed a significant higher frequency of the A allele compared to the controls (0.19 vs. 0.11; p=0.001). After adjustment by a stepwise logistic regression method, hypertension, dyslipidemia, and CA+AA genotype were found to be significantly associated with T2D. CONCLUSION: The present study showed a significant and independent association between the -863C/A polymorphism of the TNFα gene and type 2 diabetes in the Tunisian population.

Abnormal circulating levels of matrix metalloproteinases and their inhibitors in diabetes mellitus.

BACKGROUND: The aim of this study was to determine plasma levels of matrix metalloproteinases (MMPs) 2, 3, and 9 and their tissue inhibitors (TIMPs) 1 and 2 in type 2 diabetic patients (T2DM) compared to healthy subjects. METHODS: The study involved 54 patients with T2DM and 57 age and gender matched healthy adults as controls. MMPs 2 and 9 were analyzed by gelatin zymography and MMP-3 and TIMPs 1 and 2 by ELISA. RESULTS: For technical feasibility, MMPs 2 and 9 were expressed in pro forms. Pro-MMP-9 was significantly higher (p < 0.05), whereas TIMP-1 and TIMP-2 levels were significantly decreased (p < 0.01) in patients with T2DM compared to controls. The MMP-3/TIMP-1 and the MMP-3/TMP-2 ratios were significantly higher in T2DM patients than controls (p < 0.05). Fasting plasma glucose was inversely correlated with TIMP-1 (r = -0.412, p < 0.01) and TIMP-2 (r = -0.315, p < 0.001), but was not associated with MMPs. CONCLUSIONS: The present study identified abnormalities in plasma markers for extracellular matrix metabolism in T2DM. The new parameters would constitute an effective approach to explore the complications of uncontrolled diabetes.

Gender-specific effect of Pro12Ala polymorphism in peroxisome proliferator-activated receptor gamma-2 gene on obesity risk and leptin levels in a Tunisian population.

OBJECTIVES: This study was undertaken to investigate the impact of the Pro12Ala (rs1801282) polymorphism of the peroxisome proliferator-activated receptor gamma-2 (PPARgamma-2) gene on obesity or body mass index (BMI) and plasma leptin, insulin, adiponectin and lipid levels in a sample of the Tunisian population. DESIGN AND METHODS: The study included 387 obese patients and 288 control subjects. The Pro12Ala genotype was determined by polymerase chain reaction followed by a digestion with the restriction of endonuclease BstUI. RESULTS: In the whole population, there is no significant difference in genotype frequencies of the Pro12Ala polymorphism between obese patients and controls. However, separate analysis by gender revealed that obese men (but not women) had significantly higher frequency of Pro/Ala genotypes compared to controls (12.2% vs. 4.1%; chi(2)=6.76, p=0.009). In comparison to Pro/Pro homozygotes, Ala-allele bearers had a significantly higher risk of obesity [OR (95% CI)=3.26 (1.28-8.33)]. When obese subjects were stratified according to type 2 diabetes status, the association with obesity was only significant in obese non-diabetic patients [OR (95% CI)=3.74 (1.43-9.74), p=0.007]. Additionally, obese male patients carrying the Ala-allele had significantly higher body mass index (p=0.007) and plasma leptin levels (p=0.023) compared to those homozygous for Pro-allele. The significant effect of Pro12Ala polymorphism on plasma leptin levels disappeared after adjustment for age and BMI. CONCLUSION: The present study provides evidence that the Pro12Ala polymorphism of the PPARgamma-2 gene is associated with obesity in non-diabetic men from Tunisian origin.

Association of G-2548A LEP polymorphism with plasma leptin levels in Tunisian obese patients.

OBJECTIVES: The aim of this study was to examine the association of the G-2548A polymorphism of the human leptin gene (LEP) with body mass index (BMI), plasma leptin, insulin, and lipid parameters in a sample of Tunisian population. DESIGN AND METHODS: Two hundred and twenty nine obese patients (BMI>or=30 kg/m(2)) were screened and compared to 251 normal weight subjects (BMI<25 kg/m(2)). The human leptin gene promoter G-2548A genotype was determined by polymerase chain reaction followed by a digestion with the restriction of endonuclease CfoI. RESULTS: In the entire study sample, carriers of -2548A allele had significantly lower leptin levels than homozygous for -2548G allele (14.28+/-9.10 ng/mL vs. 18.27+/-12 ng/mL, p<0.001 respectively) adjusted for BMI and gender. In obese patients but not control, subjects carrying the -2548A allele exhibited lower leptin levels than those with GG genotype (16.96+/-8.27 ng/mL vs. 21.37+/-11.72 ng/mL, p=0.001 respectively) adjusted for BMI and gender. In this group, carriership of the -2548A allele was identified, by multiple linear regression models, as significant independent predictor for leptin levels variability. Separate analyses by gender revealed that only in obese women, the -2548A allele was found to be associated with lower leptin levels independently of BMI (p=0.004). CONCLUSIONS: The present study showed that G-2548A LEP polymorphism is associated with lower leptin levels in Tunisian obese women.

Increased expression of plasma membrane Ca(2+)ATPase 4b in platelets from hypertensives: a new sign of abnormal thrombopoiesis?

Platelet Ca(2+) homeostasis is controlled by a multi-Ca(2+)ATPase system including two PMCA (plasma membrane Ca(2+)ATPase) and seven SERCA (sarco/endoplasmic reticulum Ca(2+)ATPase) isoforms. Previous studies have shown similar platelet Ca(2+) abnormalities in diabetic and hypertensive patients, including an increase in intracellular [Ca(2+)](I), a possible modulation of PMCA activity and increased PMCA tyrosine phosphorylation. Very recently, we found that platelets from diabetic patients also exhibited increased PMCA4b expression. In the present study we looked for further similarities between diabetic and hypertensive patients. We first confirmed a decrease in Ca(2+)ATPase activity (mean 55 + 7%) in mixed platelet membranes isolated from 10 patients with hypertension compared with those from 10 healthy controls. In addition, the decreased Ca(2+)ATPase activity correlated with the DBP of the different patients, as expected for PMCA activity. Second, we performed a pilot study of six hypertensives to examine their expressions of PMCA and SERCA mRNA and proteins. Like the diabetic patients, 100% of hypertensives were found to present a major increase in PMCA4b expression (mean value of 218 +/- 21%). We thus determined that platelets from diabetic and hypertensive patients showed similar increased PMCA4b isoform. Since increased PMCA4b expression was recently found to be associated with a perturbation of megakaryocytopoiesis, these findings may also point to an abnormality in platelet maturation in hypertension.