Association of Nephrolithiasis and Gene for Glucose Transporter Type 9 (SLC2A9): Study of 145 Patients

Aim

To investigate the association of nephrolithiasis and solute carrier family 2, facilitated glucose transporter, member 9 (SLC2A9), also known as glucose transporter type 9, Glut9.

Methods

A total of 145 participants were recruited in the period April-October 2008 from the Department of Mineral Research of the Medical School Osijek, Osijek, Croatia; 58 (40%) had confirmed nephrolithiasis and 87 (60%) were asymptomatic. Four single nucleotide polymorphisms (SNP) from the SLC2A9 gene were genotyped in both groups (rs733175, rs6449213, rs1014290, and rs737267).

Results

There was a weak but significant association of all 4 SNPs and nephrolithiasis (P = 0.029 for rs733175; P = 0.006 for rs6449213; P = 0.020 for rs1014290, and P = 0.011 for rs737267). Logistic regression in an age- and sex-adjusted model suggested that genotype C/T for rs6449213 had odds ratio for nephrolithiasis of 2.89 (95% confidence interval 1.13-7.40). This SNP explained a total of 4.4% of nephrolithiasis variance.

Conclusion

Development of nephrolithiasis may be associated with SLC2A9 gene. Further studies are needed to clarify the role of SLC2A9 gene as a link between uric acid and nephrolithiasis.Renal stone formation (nephrolithiasis) is a disease characterized by the existence of solid deposits in the upper parts of the urinary tract (1). It is estimated to affect between 3%-9% of the population, with large differences between various populations (2,3). There is a number of causes that may lead to the renal stones formation, including diet and obesity status, some drugs, other diseases, climate changes, metabolic disorders, and genetic factors (2,4,5). The complexity of this disease caused researchers to consider nephrolithiasis as one feature of a broader systemic disease, rather than a local disease restricted to a single organic system (6). This is especially interesting in relation to gout and metabolic syndrome, which are both systemic disorders in close relation to nephrolithiasis (6-8). Even the cohort studies have confirmed the association of gout and kidney stones, suggesting that the history of gout increases the risk for kidney stones (9). Another study showed that, in the age-adjusted model, gout had an odds ratio of 1.97 for previous kidney stones (95% confidence interval [CI], 1.37-2.83) and that even after adjustment for sex, race, body mass index, and presence of hypertension the odds ratio remained significant (10).Genetic contribution to renal stones formation has been identified long time ago (2). In line with these suggestions, heritability of some of the traits associated with nephrolithiasis has been shown to be as high as 95% (11). Heritability of the urinary stones was reported to be lower (56%) (12), but still sufficiently high to be considered a substantial genetic proportion of variance and suggesting that it may be under genetic control. So far, a number of studies have established a link between predominantly oxalate kidney stones and several genes, including vitamin-D receptor gene (VDR) and calcitonin receptor (CTR) gene (13), heparan sulfate (HSPG2) gene (14), or fibronectin gene (FN1) (14).The quantitative trait associated with nephrolithiasis is the serum uric acid concentration, which is under strong genetic control by the gene for glucose transporter type 9 (SLC2A9 or Glut 9) (15). The gene was initially described in an isolated island community (16,17), where genetic properties of the population are expected to act in favor of facilitated gene mapping efforts (18). Subsequent meta-analysis of 14 populations confirmed the association of this gene with serum uric acid concentrations (19). This led to a number of clinical studies that have confirmed its involvement in the uric acid metabolism, including urate handling in the kidney and uptake in the liver (20,21). Based on the previous suggestions that gout and nephrolithiasis may share a common pathway (15), it might be interesting to see if SLC2A9 could explain the commonalities in patients with any of the following conditions. Therefore, the aim of this study was to investigate the association of nephrolithiasis and genetic variants of the SLC2A9.     

IL-18激活NF-κB细胞信号通路对人脐静脉内皮细胞损伤作用的体外研究

目的 探讨促炎因子白细胞介素-18(IL-18)通过激活核因子-κB(NF-κB)介导的细胞信号通路 ,对静脉内皮细胞功能的影响及其与深静脉血栓形成(DVT)的联系.方法 利用重组人IL-18作用体外培养的人 脐静脉内皮细胞(HUVECs),并以NF-κB激活抑制剂进行干预,通过实时荧光定量PCR、Western blot、免疫荧 光、流式细胞仪等检测手段,验证IL-18是否通过激活NF-κB介导的细胞信号转导通路,影响HUVECs正常状态及 血管性血友病因子(vWF)、P-选择素(P-selectin)、组织型纤溶酶原激活物(t-PA)等内皮细胞功能标记物 的表达,结合既往研究对IL-18参与DVT的机制进行综合分析.结果 IL-18可激活内皮细胞内NF-κB,使细胞核 内p65表达增高、细胞内IκBα表达降低,并使HUVECs早期凋亡细胞明显增多;添加QNZ(EVP4593)可使IL-18对 NF-κB的激活作用明显抑制,细胞损伤、凋亡的发生显著减少;IL-18可促使vWF、P-selectin和t-PA等DVT相 关的内皮细胞标志物发生表达异常(P<0.05),而各标志物可在NF-κB激活抑制后恢复常规表达.结论 IL-18 及NF-κB间的相互作用导致HUVECs生长状态和功能异常,可能是与DVT发病相关的疾病机制.     

Component Position and Metal Ion Levels in Computer-Navigated Hip Resurfacing Arthroplasty

Background

Metal ion levels are used as a surrogate marker for wear in hip resurfacing arthroplasties. Improper component position, particularly on the acetabular side, plays an important role in problems with the bearing surfaces, such as edge loading, impingement on the acetabular component rim, lack of fluid-film lubrication, and acetabular component deformation. There are little data regarding femoral component position and its possible implications on wear and failure rates. The purpose of this investigation was to determine both femoral and acetabular component positions in our cohort of mechanically stable hip resurfacing arthroplasties and to determine if these were related to metal ion levels.

Segmental response of the lower esophageal sphincter to increased intragastric pressure

An important controversy exists concerning the adaptive capacity of the lower esophageal sphincter (LES) in response to increases in intragastric pressure. This capacity would characterize the LES as a dynamic element in preventing gastroesophageal reflux (GER). This physiological property was studied in 15 male cats using an experimental model in which the gastroesophageal antireflux barrier was generated eyclusively by the intrinsic tone of the LES. Under these conditions, the intragastric pressure (GP) and sphincter pressure (LESP) were measured by electromanometric procedures. When the gastric lumen was perfused with known volumes (25, 50, 75, 100, 125, 150 ml) of saline solution, increases in GP and LESP were observed. Both pressures increased slowly as the gastric volume rose, and when both values were equal, GER appeared. Studying the physiological properties of the LES by direct methods in this model, we conclude that (a) there is segmental pressure response of the LES when faced with direct opening stimulation such as an increase in GP; and (b) the increase in LES resting tone has a linear relation with the increase in GP.     

Leprosy epidemics during history increased protective allele frequency of PARK2/PACRG genes in the population of the Mljet Island, Croatia

Introduction

Two regulatory polymorphisms (rs1040079 and rs9356058) shared by PARK2 and PACRG genes were identified as major risk variants for leprosy susceptibility. The aim of this study was to investigate if allele frequencies of these polymorphisms in the isolated population of the island of Mljet, which served as a quarantine for leprosy patients during past centuries, were different to allele frequencies in two control populations with no history of leprosy.

Subjects and methods

This study included 88 unrelated Caucasian individuals from the island of Mljet while two control groups included 93 individuals from the island of Rab and 160 individuals from the region of Split. Genotyping for rs1040079 and rs9356058 was performed by “real-time” PCR analysis. We also compared the allele frequency of the rs9356058 polymorphism from the population of Mljet with allele frequencies derived from the existing genome wide association scans in two additional island populations, Vis (924 subjects) and Korcula (909 subjects).

Results

We found a significant increase in the frequency of rs9356058 allele C in the population of Mljet when compared to both control groups. We also observed a significant increase in the frequency of rs1040079 allele A in the population of Mljet when compared with the population of Rab, however this increase was not significant when compared with the population of Split. Allele frequencies of both examined polymorphisms did not differ between the two control populations. Protective haplotype rs9356058-rs1040079 CA was also more frequent in the population of Mljet compared with the Rab and Split populations. In addition, an increase of frequency of rs9356058 allele C was also observed in the population of Mljet when compared with the frequency in the Korcula population.

Conclusion

The results of our study show the association of polymorphisms rs9356058 and rs1040079 in gene PARK2/PACRG with leprosy. The results of our study indicate that exposure to leprosy and mortality in the population caused by leprosy on Mljet resulted in the selection of rs9356058 “protective” C allele in the PARK2 gene, while this was not observed in the two control groups. This is the first study to assess the genetic susceptibility to leprosy in a European population.     

Novel association to the proprotein convertase PCSK7 gene locus revealed by analysing soluble transferrin receptor (sTfR) levels

The level of body iron storage and the erythropoietic need for iron are indicated by the serum levels of ferritin and soluble transferrin receptor (sTfR), respectively. A meta-analysis of five genome-wide association studies on sTfR and ferritin revealed novel association to the PCSK7 and TMPRSS6 loci for sTfR and the HFE locus for both parameters. The PCSK7 association was the most significant (rs236918, P = 1.1 × 10E-27) suggesting that proprotein convertase 7, the gene product of PCSK7, may be involved in sTfR generation and/or iron homeostasis. Conditioning the sTfR analyses on transferrin saturation abolished the HFE signal and substantially diminished the TMPRSS6 signal while the PCSK7 association was unaffected, suggesting that the former may be mediated by transferrin saturation whereas the PCSK7-associated effect on sTfR generation appears to be more direct.     

Genetic architecture of circulating lipid levels

Serum concentrations of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs) and total cholesterol (TC) are important heritable risk factors for cardiovascular disease. Although genome-wide association studies (GWASs) of circulating lipid levels have identified numerous loci, a substantial portion of the heritability of these traits remains unexplained. Evidence of unexplained genetic variance can be detected by combining multiple independent markers into additive genetic risk scores. Such polygenic scores, constructed using results from the ENGAGE Consortium GWAS on serum lipids, were applied to predict lipid levels in an independent population-based study, the Rotterdam Study-II (RS-II). We additionally tested for evidence of a shared genetic basis for different lipid phenotypes. Finally, the polygenic score approach was used to identify an alternative genome-wide significance threshold before pathway analysis and those results were compared with those based on the classical genome-wide significance threshold. Our study provides evidence suggesting that many loci influencing circulating lipid levels remain undiscovered. Cross-prediction models suggested a small overlap between the polygenic backgrounds involved in determining LDL-C, HDL-C and TG levels. Pathway analysis utilizing the best polygenic score for TC uncovered extra information compared with using only genome-wide significant loci. These results suggest that the genetic architecture of circulating lipids involves a number of undiscovered variants with very small effects, and that increasing GWAS sample sizes will enable the identification of novel variants that regulate lipid levels.     

Beneficial effect of a novel pentadecapeptide BPC 157 on gastric lesions induced by restraint stress,ethanol, indomethacin,and capsaicin neurotoxicity

Very recently, the integrity of capsaicin somatosensory neurons and their protection were suggested to be related to the activity in nociception of a newly discovered 15-amino acid peptide, BPC 157, shown to have strong beneficial effect on intestinal and liver lesions. Therefore, from this viewpoint, we have studied the gastroprotective effect of the pentadecapeptide BPC 157, on gastric lesions produced in rats by 96% ethanol, restraint stress, and indomethacin. The possible involvement of sensory neurons in the salutary actions of BPC 157 (10µg/kg, 10 ng/kg intraperitoneally) was studied with capsaicin, which has differential effects on sensory neurons: a high dose in adult (125 mg/kg subcutaneously, 3 months old) or administration (50 mg/kg subcutaneously) to neonatal animals (age of the 7 days) destroys sensory fibers, whereas a low dose (500µg/kg intraperitoneally) activates neurotransmitter release and protective effects on the mucosa. In the absence of capsaicin, BPC 157 protected gastric mucosa against ethanol, restraint, and indomethacin application. In the presence of neurotoxic doses of capsaicin, the negative influence of capsaicin on restraint, ethanol, or indomethacin lesions consistently affected salutary activity of BPC 157. However, BPC 157 protection was still evident in the capsaicin-treated rats (either treated as adults or as newborns) in all of these assays. Interestingly, after neonatal capsaicin treatment, a complete abolition of BPC gastroprotection was noted if BPC 157 was applied as a single nanogram-regimen, but the mucosal protection was fully reversed when the same dose was used daily. In line with the excitatory dose of capsaicin the beneficial effectiveness of BPC 157 appears to be increased as well. Taken together, these data provide evidence for complex synergistic interaction between the beneficial effectiveness of BPC 157 and peptidergic sensory afferent neuron activity.