Afig Berdeli

COQ6 mutations in human patients produce nephrotic syndrome with sensorineural deafness

Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of end-stage renal failure. Identification of single-gene causes of SRNS has generated some insights into its pathogenesis; however, additional genes and disease mechanisms remain obscure, and SRNS continues to be treatment refractory. Here we have identified 6 different mutations in coenzyme Q10 biosynthesis monooxygenase 6 (COQ6) in 13 individuals from 7 families by homozygosity mapping. Each mutation was linked to early-onset SRNS with sensorineural deafness. The deleterious effects of these human COQ6 mutations were validated by their lack of complementation in coq6-deficient yeast. Furthermore, knockdown of Coq6 in podocyte cell lines and coq6 in zebrafish embryos caused apoptosis that was partially reversed by coenzyme Q10 treatment. In rats, COQ6 was located within cell processes and the Golgi apparatus of renal glomerular podocytes and in stria vascularis cells of the inner ear, consistent with an oto-renal disease phenotype. These data suggest that coenzyme Q10-related forms of SRNS and hearing loss can be molecularly identified and potentially treated.

TLR-2 gene Arg753Gln polymorphism is strongly associated with acute rheumatic fever in children

The recently described family of toll-like receptors (TLRs) is a key player in host immunity by mediating inflammatory reactions against a wide range of pathogens. Mutations and polymorphisms in TLRs have revealed the importance of TLRs in human defence against diseases. TLR-2 is reported to interact with different bacterial structures, including lipoproteins, peptidoglycan and lipoteichoic acid. To assess the role of TLR-2 gene polymorphism in acute rheumatic fever (ARF) etiopathology, 61 independent Caucasian Turkish patients and 91 child and 116 adult controls were studied. Antistreptolycin O, C-reactive protein, sedimentation and white blood cell counts were studied to evaluate the clinical characteristics of the patients. Genomic DNA was extracted from peripheral blood using a standard column extraction technique. The Arg753Gln and Arg677Trp polymorphisms were genotyped by polymerase chain reaction (PCR) restriction fragment length polymorphism. The PCR products for the TLR-2 gene were analysed on 1.5% agarose gel pre-stained with ethidium bromide. Compared with healthy adult controls, the Arg753Arg genotype was significantly decreased in the entire group of ARF cases [odds ratio (OR) 0.01, 95% confidence interval (95% CI) 0.0034–0.031, p<0.0001]. Significantly, ARF patients were just 16 times more frequent with Gln allele (OR 15.6, 95% CI 7.87–30.8, p<0.0001). Moreover, evidence for an intensifying effect of the Gln allele was noteworthy when patients with Arg753Gln genotype were compared with healthy controls (OR 97.1, 95% CI 32.5–290, p<0.0001). However, no Arg677Trp polymorphism was detected in either patients or controls. Our data suggest that there is strong evidence for the biological role of TLR-2 in ARF. The common TLR-2 Arg to Gln polymorphism at position 753 significantly contributes to the pathogenesis of ARF. These results will allow the construction of a profile of individuals prone to ARF and may assist in developing new therapies.

Proinflammatory cytokines, prostaglandins and zinc in febrile convulsions

Abstract 
 Background : Some changes in the levels of proinflammatory cytokines, prostaglandins and zinc (Zn) in peripheral blood and cerebrospinal fluid (CSF) have been suggested to occur for the pathogenesis of febrile convulsions (FC).

Association of TLR2 gene Arg753Gln polymorphism with urinary tract infection in children.

The aim of this study is to investigate Arg753Gln allele polymorphisms of toll‐like receptor‐2 (TLR2) gene distribution, allele frequency in urinary tract infection (UTI) and genotype–phenotype association of TLR2 gene in children with UTI. The polymorphism was investigated in 124 children with UTI (22 boys and 102 girls; mean age 5.81 ± 3.47 years) with direct DNA sequencing‐based method. TLR2 gene Arg753Gln allele frequency was higher in the patient group when compared with control group (OR 3.14, 95%CI 1.53–6.44, P < 0.001). The frequency of the Arg753Gln allele was significantly higher in gram‐positive group than in gram‐negative group (OR 7.64, 95%CI 2.80–20.81, P < 0.001). The frequency of UTI was found significantly higher in the Arg753Gln allele carriers of TLR2 gene than the non‐carriers (OR 4.94, 95%CI 1.09–22.33, P < 0.05). Similarly, the incidence of asymptomatic UTI was also found significantly higher in the group carrying Arg753Gln allele (OR 3.73, 95%Cl 1.54–9.04, P < 0.05). As a result, we suggest that TLR2 gene could be the predisposing factor for urinary tract infection. Additionally, we observed that subjects carrying the TLR2 Arg753Gln allele had higher risk of urinary tract infection with gram‐positive pathogens, history of more than two attacks of UTI and asymptomatic UTI.

Renin-angiotensin system gene polymorphisms and premature coronary heart disease

Introduction Experimental and clinical studies demonstrated that the renin-angiotensin system (RAS) affects the pathogenesis of atherosclerosis and prognosis of coronary heart disease (CHD). The aim of this study was to investigate the genotype distribution and the allele frequencies of three RAS genes polymorphisms and their effects on premature CHD in a Turkish population. Materials and methods One-hundred and fifteen Turkish patients with premature CHD and 128 controls were included into the study. Angiotensin-converting enzyme (ACE), angiotensin II type 1 (AT1) receptor and angiotensinogen (AGT) gene polymorphisms were analysed by polymerase chain reaction (PCR ) and restriction fragment length polymorphism (RFLP). Results The patients group showed an increased frequency of the ACE D allele compared with controls (65% vs. 35%, p=0.0001). There was a significant association between the DD genotype and premature CHD (ACE DD vs. ID and II; odds ratio [OR]=2.82 [CI 95% 1.33—2.91, p=0.002]). Also, we observed increased premature CHD risk associated with higher frequencies of the AGT MM genotype in patients when compared with controls (AGT MM vs. TT and MT, OR=1.92 [CI 95% 1.11—3.33, p=0.018]). We found a significant association between AT1-receptor AA genotype and decreased risk of premature CHD (AT1R AA vs. AC and CC, OR= 0.57[CI 95% 0.34—0.95, p=0.03]). Conclusions We demonstrated that increased premature CHD risk is associated with higher frequencies of the ACE DD and AGT MM genotypes. These findings indicate a synergistic contribution of ACE DD and AGT MM polymorphisms to the development of premature CHD. Also, our results suggest that family history, smoking, diabetes, hypertension, obesity and ACE DD genotype were independent risk factors for premature CHD.

Alterations of blood pressure in type 1 diabetic children and adolescents

The aim of this study was to assess the association between metabolic control, microalbuminuria, and diabetic nephropathy with ambulatory blood pressure monitoring (ABPM) in normotensive individuals with type 1 diabetes mellitus (DM). ABPM was undertaken in 68 normotensive type 1 diabetic patients with a mean age of 14.4±4.2 years. Microalbuminuria was diagnosed on the basis of a urinary albumin excretion rate grater than 20 μg/min in two of the three 24-h urine collections. Hypertension (HT) frequency was greater in the microalbuminuric patients than normoalbuminuric patients (54 vs 17.54%, p=0.05) with ABPM. Microalbuminuric patients had a higher diastolic pressure burden than normoalbuminuric patients. There were no differences in systolic and diastolic dips between the two groups. Diastolic pressure loads in all periods showed a significant correlation with duration of diabetes, mean HbA1c from the onset of diabetes, and level of microalbuminuria. Nocturnal dipping was reduced in 41.2% of the patients. In the normoalbuminuric group 41.1% and in the microalbuminuric group 63.6% were nondippers. Our data demonstrate higher 24-h and daytime diastolic blood pressure load and loss of nocturnal dip in type 1 diabetic adolescents and children. High diastolic blood pressure burden in diabetic patients could represent a risk for nephropathy.

Effect of MMP‐1 promoter polymorphisms on GCF MMP‐1 levels and outcome of periodontal therapy in patients with severe chronic periodontitis

AIMS The aims of this study were to investigate (1) the matrix metalloproteinase-1 (MMP-1) promoter polymorphisms in severe chronic periodontitis (CP), (2) the relationship of periodontal therapy outcome with these genotypes, and (3) the gingival crevicular fluid (GCF) MMP-1 levels-MMP-1 genotype correlation. MATERIAL AND METHODS Genomic DNA was obtained from the peripheral blood of 102 patients with severe CP and 98 periodontally healthy subjects. MMP-1 -519A/G and -1607 1G/2G polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Fifty-eight CP patients received non-surgical periodontal therapy and were followed for 6 months. Clinical periodontal parameters and GCF samples were collected at baseline and at 6 months. GCF MMP-1 levels were analysed by enzyme-linked immunosorbent assay (ELISA). RESULTS The distribution of MMP-1 genotypes did not significantly differ between the study groups. On the other hand, the -1607 2G allele frequency of severe CP patients was higher than that of healthy subjects. MMP-1 -519G allele carriers had higher GCF MMP-1 levels and percentage of sites with 4-6 mm clinical attachment level (CAL) compared with AA genotypes after non-surgical periodontal therapy (p<0.05). CONCLUSIONS These data suggest that the -1607 2G polymorphic allele of the MMP-1 gene could be associated with susceptibility to severe CP in the Turkish population. It seems that -519AG and GG genotypes could play a role in the outcome of periodontal therapy.

Insulin-Like Growth Factor Attenuates Apoptosis and Mucosal Damage in Hypoxia/Reoxygenation-Induced Intestinal Injury

Objective: Necrotizing enterocolitis (NEC) is a potentially lethal disease among premature infants. The aim of the present study was to investigate whether hypoxia-reoxygenation (H/R)-induced intestinal injury was due to increased apoptosis of the intestinal mucosa in young mice and whether pre-treatment of the animals with recombinant human insulin-like growth factor-I (IGF-I), a known anti-apoptotic factor, could protect the intestinal cells from H/R-induced apoptosis or intestinal injury. Study Design: Young mice were divided into three groups: group 1 mice (H/R) were hypoxia-reoxygenation; group 2 mice (H/R + IGF-I) were treated with recombinant human IGF-I by intraperitoneal injection (1 µg/g b.w. once daily) for 7 days, and group 3 mice served as control. Hypoxia was induced by placing young mice in a Plexiglas chamber consisting of 10% oxygen for 60 min. After hypoxia, the young mice were reoxygenated for 10 min with 100% oxygen. Intestinal generation of substances reactive to thiobarbituric acid (TBARS) and active caspase-3 were measured in H/R-induced intestinal injury. Results: Increased numbers of apoptotic cells (apoptotic index) across the villi in young mice subjected to H/R were observed with the TUNEL reaction whereas few apoptotic cells existed in the control animals. In addition, H/R-induced intestinal damage in the H/R + IGF-I group was greatly attenuated, with necrosis limited partially to the mucosa. Tissue-active caspase-3 levels in the H/R group were found to be significantly higher when compared with that of the H/R + IGF-I group of mice and control. However, TBARS concentrations in the intestine were similar in H/R groups when compared to the intestine of control animals. Conclusion: The present study suggests that both necrosis and apoptosis, via mechanisms occurring due to oxygen-derived free radicals and activation of caspase-3, play a role in the pathogenesis of H/R-induced bowel injury. We also show that IGF-I protect intestinal mucosa from necrosis and apoptosis from intestinal H/R injury.

Positive association of macrophage migration inhibitory factor gene-173G/C polymorphism with biliary atresia.

Background: Macrophage migration inhibitory factor (MIF) is a pleiotrophic lymphocyte and macrophage cytokine; it is likely to play an important role in innate immunity. Its expression was increased in several inflammatory diseases, and MIF gene polymorphisms have an effect on disease outcome and response to glucocorticoid treatment. Aim: To investigate the role of the 173G/C polymorphism of the MIF gene for susceptibility to biliary atresia (BA). Method: Between February 2002 and November 2004, 18 patients (mean age 1 ± 0.4 years) diagnosed as having BA were studied. After informed consent, blood was collected, and DNA was obtained. MIF 173C/G polymorphism was detected using the polymerase chain reaction-restriction fragment length polymorphism based method. BA patients were compared with a group of chronic liver disease patients (CLD) (n = 36) and a group of unrelated healthy controls (n = 103). Results: MIF-173C allele frequency was significantly higher than both the CLD and healthy control groups (P = 0.03, odds ratio [OR] 4.4, 95% confidence interval [CI] 1.3-15.1; P = 0.000, OR 4.1, 95% CI 2.3-7.6, respectively). Univariate analysis showed that MIF-173G/C polymorphism was significantly associated with BA (for GC genotype, OR = 6, 95 % CI 2.8-11.5, P = 0.000). There was no significant correlation between pediatric end stage liver disease score and MIF genotypes both in BA and CLD groups. Conclusion: Our results suggest that the -173C allele of the MIF gene might be associated with the susceptibility to BA.

TRPC6 gene variants in Turkish children with steroid-resistant nephrotic syndrome

BACKGROUND In steroid-resistant nephrotic syndrome (SRNS), a considerable number of patient progress to end-stage renal disease (ESRD), despite aggressive therapy. The latest advance in familial focal segmental glomerulosclerosis (FSGS) has been the discovery of a mutant form of canonical transient receptor potential channel 6 (TRPC6) leading to FSGS through unclear mechanisms. The aim of this study is to screen for TRPC6 mutations in familial and sporadic SRNS patients. METHODS Twenty-five children with SRNS originating from Turkey were included in this study. Nine patients had familial and 16 patients had sporadic SRNS. Mutation analysis was performed in all 13 coding exons of the TRPC6 gene with the direct DNA sequencing method. The control group consisted of 50 normal healthy children originating from Turkey. RESULTS No mutation was detected in nine children (four familial, five sporadic). A variant (L395A) in one patient, intronic nucleotide substitution (c.171 + 16 A>G and c.171 + 86 G>C) in six patients and previously described missense (A404V; rs36111323) and synonymous (N561N; rs12366144) aminoacid variants in nine patients were found. Among patients with intronic, missense and synonymous aminoacid variants, 5 patients had familial and 11 patients had sporadic SRNS. Their mean age at onset of proteinuria was 2.6 ± 1.7 years. Seven cases (three familial, four sporadic) progressed to ESRD with a mean time of 10.2 ± 2.9 years. CONCLUSIONS In conclusion, analysis of TRPC6 gene mutations in FSGS will provide new insights into the pathogenesis of nephrotic syndrome. Previous works have emphasized that the patients with only hereditary familial FSGS carried a missense mutation in the TRPC6 gene. Our findings suggest that TRPC6 mutations may also have an important role in the pathogenesis of sporadic SRNS.