Search

Objectives: To examine the possible implication of the mRNA-binding protein serine/arginine protein 55 (SRp55, also known as SRSF6) rs2235611 single nucleotide polymorphism (SNP) in the genetic predisposition to systemic sclerosis (SSc) susceptibility and clinical phenotype., Methods: A total population of 872 white Italian individuals (414 SSc patients, 458 controls) was studied. SSc patients were assessed for limited and diffuse cutaneous subsets and the presence of autoantibodies, interstitial lung disease (ILD), and nailfold videocapillaroscopy (NVC) abnormalities. The SRp55 rs2235611 SNP was genotyped by TaqMan real-time PCR., Results: SRp55 rs2235611 genotype distribution and allele frequency were similar in SSc and healthy controls, though a trend toward significance was observed for genotype distribution (p=0.07). The SRp55 rs2235611 AA genotype significantly influenced the predisposition to SSc (p= 0.03). The SRp55 rs2235611 A minor allele and AA genotype showed a significant risk association with susceptibility to SSc-related ILD (A allele: p=0.046; AA genotype: p=0.007). A significant association of the AA genotype with SSc late NVC pattern was also found (p=0.006). After Bonferroni correction for multiple comparisons, the risk association of the SRp55 rs2235611 AA genotype with SSc-related ILD and late NVC pattern remained significant (padj=0.049 and padj=0.042, respectively)., Conclusions: The SRp55 rs2235611 AA genotype significantly influences the susceptibility to SSc, and specifically associates with the presence of SSc-related ILD and late NVC pattern. Further in-depth studies on the SRp55 gene locus will hopefully contribute to extend our knowledge of the genetic predisposition to major SSc-related manifestations such as pulmonary fibrosis and peripheral microvasculopathy.

Objective: Microvascular disorders are relevant in systemic sclerosis (SSc). Hyperviscosity, due to alterations of blood cells and plasma components, may play a role in the pathogenesis of microcirculatory disorders. An impaired availability of nitric oxide, related to polymorphisms in NOS3, the gene for endothelial cell nitric oxide synthase, might influence erythrocyte deformability. We undertook this study to investigate the hemorheologic profile in SSc and the role of NOS3 polymorphisms in modulating the hemorheologic status of SSc patients., Methods: We studied 113 consecutive SSc patients (75 with limited cutaneous SSc [lcSSc] and 38 with diffuse cutaneous SSc [dcSSc]) and 113 healthy controls. The hemorheologic profile was obtained by assessing whole blood viscosity (WBV; at shear rates of 0.512 and 94.5 seconds(-1)), plasma viscosity (PLV; at a shear rate of 94.5 seconds(-1)), and erythrocyte deformability index (DI). We determined NOS3 polymorphisms by molecular analysis., Results: A marked alteration of hemorheologic parameters was found both in patients with lcSSc and in those with dcSSc compared with controls (P < 0.0001). In multivariate analysis, rheologic variables were significantly associated with the disease (for WBV at a shear rate of 94.5 seconds(-1), odds ratio [OR] 5.4, 95% confidence interval [95% CI] 1.4-19.9, P = 0.01; for PLV, OR 2.8, 95% CI 1.2-6.5, P = 0.01; for DI, OR 3.9, 95% CI 1.4-10.8, P = 0.007), and NOS3 -786C and 894T alleles significantly affected the DI (for -786C allele, OR 2.3, 95% CI 1.01-5.4, P = 0.04; for 894T allele, OR 2.2, 95% CI 1.01-4.8, P = 0.04). The simultaneous presence of the -786C and 894T alleles represented a susceptibility factor for SSc (OR 2.8, 95% CI 1.4-5.7, P = 0.004)., Conclusion: Our findings document an altered rheologic profile in SSc and demonstrate a relationship between this alteration and NOS3 polymorphisms, thus shedding light on a potential novel mechanism influencing the microcirculation in this disease.

Objective: SSc is characterized by immune dysfunction and microvascular involvement. A different genetic background may determine a different polymorphic allele frequency between different populations, and data from literature reported conflicting results about the role of genetic components in predisposing to the disease. We carried out this study in order to compare the ACE I/D polymorphism genotype distribution and alleles frequency in two different populations from the Mediterranean area., Methods: Forty-eight Italian and 41 Greek SSc patients compared with 112 Italian and 93 Greek controls, have been studied. The ACE I/D polymorphism has been analysed., Results: The genotype distribution and allele frequency were in Hardy-Weinberg equilibrium for Italian and Greek SSc patients and controls. Among the Italian patients a significantly higher ACE D allele frequency than in the controls was found, whereas among the Greeks a higher prevalence was observed in the healthy subjects. A significant difference in ACE D allele frequency between Italian and Greek controls was observed (p = 0.04). ACE D allele was associated to the predisposition to SSc in Italians, but not in Greeks., Conclusion: We confirm that Italian SSc patients have a higher ACE D allele frequency that is not present in the Greek patients. Thus, the two populations living in different Mediterranean areas and resulting from the Mediterranean civilization, do not show the same ACE-gene related allele frequencies. Other populations of the Mediterranean area must be investigated by using unlinked genetic markers to verify the homogeneity of the genetic background, and to test for a "true" difference in their ethnic origin.

The main pathologic hallmark of systemic sclerosis (SSc) is endothelial derangement; the pathologic alterations of the vessel wall in SSc are strikingly similar to the modification detected in the atherosclerotic lesions, and it is now evident that SSc is also characterized by accelerated macrovascular disease. Peptides related to angiotensin II, the final product of the renin-angiotensin system (RAS), play a role as regulators of endothelial cell function. Angiotensin-converting enzyme (ACE), the key enzyme in the RAS, is the predominant pathway of angiotensin II formation in blood and tissues. In intron 16 of the gene encoding for ACE an insertion/deletion (I/D) polymorphism, consisting of the presence or absence of a 287-base pair Alu sequence, has been identified. This polymorphism has been related to ACE enzyme levels, and data from experimental studies reported a functional role for this polymorphism in modulating the angiotensin II levels. We previously documented a high ACE D allele frequency in SSc patients and its role in increasing the risk of SSc, thus suggesting that the I/D polymorphism might be a useful genetic marker to identify SSc patients at risk to develop a severe vascular disease, frequently leading to gangrene. Moreover, our preliminary data, besides supporting the role of ACE I/D polymorphism as a predisposing factor to SSc, demonstrated its involvement in accelerated macrovascular disease by increasing the intima media thickness. Therefore, in SSc, not only endothelial dysfunction, but also vascular damage, linked to ACE I/D polymorphism, may significantly contribute to accelerated macrovascular disease, as the ACE D allele, by regulating both the production of angiotensin II and the degradation of bradykinin, contributes to mechanisms involved in the induction and maintenance of vessel wall modification.

Purpose: Systemic sclerosis is characterized by progressive microvascular occlusion and fibrosis and by an imbalance in the fibrinolytic system. In vivo and in vitro studies suggest that the renin-angiotensin system partly regulates vascular fibrinolytic balance. Angiotensin II increases the production and secretion of plasminogen activator inhibitor-1, while angiotensin-converting enzyme (ACE) contributes to reduced production of tissue plasminogen activator and endothelial nitric oxide synthesis by bradykinin degradation. The aim of our study was to investigate the effects of ACE insertion/deletion (I/D) and endothelial nitric oxide synthase (eNOS) Glu298Asp (G894-->T) and T-786-->C polymorphisms in patients with systemic sclerosis., Subjects and Methods: We studied 73 consecutive patients (47 with limited and 26 with diffuse cutaneous systemic sclerosis) and 112 control subjects. ACE I/D and eNOS polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis., Results: The ACE I/D and the eNOS G894-->T polymorphisms were more common in patients than in controls (for the ACE D allele: odds ratio [OR] = 3.4; 95% confidence interval [CI]: 1.5 to 7.9; P = 0.003; for the eNOS T allele: OR = 1.9; 95% CI: 1.0 to 3.4; P = 0.04). There was no association between the eNOS T-786-->C polymorphism and systemic sclerosis., Conclusions: Our findings of an increased risk of systemic sclerosis in ACE D and eNOS 894T allele carriers suggest that these polymorphisms may contribute to the pathogenesis of the disease.