Fetuin-A gene polymorphism in patients with calcium oxalate stone disease

Molecular and pathobiological involvement of fetuin-A in the pathogenesis of NAFLD

The liver acts as a manufacturing unit for the production of fetuin-A, which is essential for various physiological characteristics. Scientific research has shown that a moderate upward push in fetuin-A serum levels is associated with a confirmed non-alcoholic fatty liver disease (NAFLD) diagnosis. Fetuin-A modulation is associated with a number of pathophysiological variables that cause liver problems, including insulin receptor signaling deficiencies, adipocyte dysfunction, hepatic inflammation, fibrosis, triacylglycerol production, macrophage invasion, and TLR4 activation. The focus of the present review is on the various molecular pathways, and genetic relevance of mRNA expression of fetuin-A which is correlated with progression of NAFLD. The other major area of exploration in the present review is based on the new targets for the modulation of fetuin-A, like calorie restriction and novel pharmacological agents, such as rosuvastatin, metformin, and pioglitazone which are successfully implicated in the management of various liver-related complications.

Effects of fetuin-A with diverse functions and multiple mechanisms on human health

Fetuin-A (Alfa 2-Heremans-Schmid) is a glycoprotein that is mainly synthesized by hepatocytes and then released into the bloodstream. While fetuin-A, a multifunctional protein, has inhibitory effects on health in the processes of calcification, mineralization, coronary artery calcification (CAC), and kidney stone formation by various mechanisms, it has such stimulatory effects as obesity, diabetes, and tumor progression processes. Fetuin-A produces these effects on the organism mainly by playing a role in the secretion levels of some inflammatory cytokines and exosomes, preventing unwanted calcification, inhibiting the autophosphorylation of tyrosine kinase, suppressing the release of adiponectin and peroxisome proliferator-activated receptor-γ (PPARγ), activating the toll-like receptor 4 (TLR-4), triggering the phosphatidylinositol 3 (PI3) kinase/Akt signaling pathway and cell proliferation, and mimicking the transforming growth factor-beta (TGF-β) receptor. In the present review, fetuin-A was examined in a wide perspective from the structure and release of fetuin-A to its effects on health.

The relationship between serum and urinary Fetuin-A levels and kidney stone formation among kidney stone patients

Introduction

Mineralization inhibitors are required to prevent the precipitation of minerals and inhibit the formation of kidney stones and other ectopic calcifications. In laboratory studies, Fetuin-A as a glycoprotein has inhibited hydroxyapatite precipitation in calcium and phosphate supersaturated solutions; however, information about patients with kidney stones is limited. The aim of this study was to investigate the association of serum and urinary Fetuin-A levels with calcium oxalate kidney stones.

Material and methods

In this case-control study, 30 patients with kidney stones and 30 healthy individuals without any history of urolithiasis who were referred to the urology ward of Sina Hospital of Tehran, Iran, in 2015 were entered into the study. All patients underwent computerized tomography scans. After collecting demographic information, serum and urine levels of Fetuin-A and some other calcification inhibitors and promoters, were measured and compared using T-test, Mann-Whitney and logistic regression between the two study groups.

Results

Patients with kidney stones, on average, had lower levels of Serum Fetuin-A (1522.27 ±755.39 vs. 1914.64 ±733.76 μg/ml; P = 0.046) as well as lower levels of Urine Fetuin-A (944.62 ±188.5 vs. 1409.68 ±295.26 μg/ml; P <0.001). Multivariate logistic analysis showed that urinary calcium and serum creatinine are the risk factors and Fetuin-A is a urinary protective factor for kidney stones.

Conclusions

PFC Our study showed that patients with kidney stones had lower serum and urinary levels of Fetuin-A. In the logistic regression model, urinary Fetuin-A was reported as a protective factor for kidney stones.

The effects of HAP and macrophage cells to the expression of inflammatory factors and apoptosis in HK-2 cells of vitro co-cultured system

This study developed an in vitro system by co-culturing HK-2 cells with different concentration of hydroxyapatite (HAP) and/or macrophage cells to simulate the internal environment of urolithiasis as far as possible, investigating the regulatory effects of macrophage cells on HAP-induced expression of relative inflammatory factors of HK-2 cells. The control group (H group) was only comprised of HK-2 cells. Experimental groups included co-culturing HK-2 cells and macrophage cells (H + M group), co-culturing HK-2 cells and HAP (H + A group), co-culturing macrophage cells and HAP (M + A group), and co-culturing HK-2 cells and macrophage cells with HAP (H + M + A group). In the H + A, M + A, and H + M + A group, we set the concentration of HAP as 5 μg/cm² (A1) and 10 μg/cm² (A2). After co-culturing for 2, 4, and 6 h, we detected the expression of CCL-2 in the liquid by ELISA. We tested the expression of LDH and ROS to evaluate the damage of HK-2 cells. We assessed the apoptosis of HK-2 cells using DAPI staining assay, flow cytometry, and the rate of BAX/BCL-2. Western Blotting detected OPN, Fetuin-A, BAX, and BCL-2 of HK-2 cells. The expression of CCL-2 in the medium of H + A1 and H + A2 group increased significantly compared with the control (P < 0.05); CCL-2 of M + A1 and M + A2 group was higher than the H + A1 and H + A2 group (P < 0.05). The expression of CCL-2 in H + M + A1 and H + M + A2 group was also higher than M + A1 and M + A2 group (P < 0.05). Compared with control, the expression of OPN, LDH release, the ratio of BAX/BCL-2, and the generation of ROS in HK-2 cells increased in a dose- and time-dependent manner. Compared with the control, the expression of Fetuin-A decreased in various degrees at different incubation periods. Especially when co-culturing for 6 h, Fetuin-A decreased most seriously in the H + M + A1 group. (1) The HAP can induce the HK-2 cells oxidative stress and inflammatory damage and apoptosis, when adding the macrophages to co-culture, macrophage cells can aggravate the damage and apoptosis of the HK-2 cells. (2) After the stimulation of HAP, the expression of OPN in HK-2 cells increased in a time- and dose-dependent manner; macrophage cells can aggravate the increase of OPN in HK-2 cells. (3) In the HAP and HK-2 cells co-cultured system, the low-level Fetuin-A of HK-2 cells may be related to the excessive consumption of Fetuin-A in the process of HAP-induced renal tubular epithelial cell excessive oxidative stress, inflammatory injury, and cell apoptosis. When adding macrophage cells to co-culture, Fetuin-A decreased even more seriously, it reminds us that macrophage cells can slightly regulate the expression of Fetuin-A in the HK-2 cells.

Urine and serum fetuin-A levels in patients with urolithiasis

Introduction:

Fetuin-A is a glycoprotein secreted by liver and has been shown to inhibit extraosseous mineralization. Urolithiasis may be a manifestation in the urinary tract due to fetuin deficiency in urine. The objective of this study was to compare the 24-h urine and serum fetuin-A levels of patients with and without urolithiasis.

Methods:

Serum and 24-h urine fetuin-A levels were measured in 41 patients with bilateral, multiple, or recurrent urinary tract calculi (Group A) and 41 matched controls with no calculi (Group B). Fetuin levels were measured by enzyme linked immunosorbent assay. Serum and urine fetuin-A levels in the two groups were compared.

Results:

The median (range) 24-h urine fetuin-A value in Group A was 11.9 (1.12–221) mg/day and in Group B was 37.7 (1.28–125) mg/day. This difference was statistically significant (Mann–Whitney test, P = 0.0169). The median (range) serum fetuin-A in Group A was 0.67 (0.05–2.68) g/L and in Group B was 0.99 (0.01–5.5) g/L. The difference between serum values in the two arms was not statistically significant (Mann–Whitney test, P = 0.1817). However, the serum creatinine-adjusted mean log serum fetuin and urine fetuin were significantly different in the two arms (P = 0.003). The mean ± standard deviation (range) serum creatinine in Group A was 0.98 ± 0.25 (0.56–1.58) mg% and in Group B was 0.83 ± 0.16 (0.58–1.18) mg% (two sample t-test, P = 0.0031).

Conclusions:

Patients with urolithiasis have lower urine fetuin-A and creatinine-adjusted serum fetuin-A levels.

Matrix-Gla Protein rs4236 [A/G] gene polymorphism and serum and GCF levels of MGP in patients with subgingival dental calculus

AIM

Matrix-Gla Protein (MGP) is one of the major Gla-containing protein associated with calcification process. It also has a high affinity for Ca2+ and hydroxyapatite. In this study we aimed to evaluate the MGP rs4236 [A/G] gene polymorphism in association with subgingival dental calculus. Also a possible relationship between MGP gene polymorphism and serum and GCF levels of MGP were examined.

MATERIAL AND METHODS

MGP rs4236 [A/G] gene polymorphism was investigated in 110 patients with or without subgingival dental calculus, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. Additionally, serum and GCF levels of MGP of the patients were compared according to subgingival dental calculus.

RESULTS

Comparison of patients with and without subgingival dental calculus showed no statistically significant difference in MGP rs4236 [A/G] gene polymorphism (p=0.368). MGP concentrations in GCF of patients with subgingival dental calculus were statistically higher than those without subgingival dental calculus (p=0.032). However, a significant association was not observed between the genotypes of AA, AG and GG of the MGP rs4236 gene and the serum and GCF concentrations of MGP in subjects.

CONCLUSION

In this study, it was found that MGP rs4236 [A/G] gene polymorphism was not to be associated with subgingival dental calculus. Also, that GCF MGP levels were detected higher in patients with subgingival dental calculus than those without subgingival dental calculus independently of polymorphism, may be the effect of adaptive mechanism to inhibit calculus formation.

Changes of serum C-reactive protein and fetuin-A levels in patients with acute angle-closure glaucoma and type 2 diabetes mellitus

AIM: To investigate the changes of serum C-reactive protein (CRP) and fetuin-A (AHSG) levels in patients with acute angle-closure glaucoma and type 2 diabetes mellitus.

METHODS: Serum levels of CRP and AHSG were determined by ELISA and nephelometry in 37 patients with acute angle-closure glaucoma and type 2 diabetes mellitus (group A) and 21 patients with acute angle-closure glaucoma only (group B). At the same time, 15 healthy controls were enrolled.

RESULTS: Serum levels of CRP and AHSG in groups A and B were significantly higher than those in group C (P < 0.05). Serum levels of CRP and AHSG in group A were significantly higher than those in group B (9.51 mg/L ± 3.21 mg/L vs 5.93 mg/L ± 0.87 mg/L; 376.33 μg/mL ± 9.17 μg/mL vs 315.59 μg/mL ± 10.75 μg/mL, P < 0.05).

CONCLUSION: CRP and AHSG may be involved in the development and pathogenesis of acute angle-closure glaucoma with type 2 diabetes mellitus.

The low levels of circulating hepatocyte growth factor in nephrolithiasis cases: independent from gene polymorphism

Environmental and genetic factors are important in development of nephrolithiasis. In a recent study, it has been demonstrated that hepatocyte growth factor (HGF) has an anti-apoptotic effect and thus can reduce the adhesion of calcium oxalate monohydrate crystals to renal epithelial cells. The aim of this study was to evaluate the HGF serum levels and its two gene polymorphisms and possible association of the two in patients with nephrolithiasis. One hundred and five patients with nephrolithiasis and 70 healthy volunteers with similar demographic features were included in this study. Serum HGF levels were measured, and HGF intron 13 C>A (in 102 stone patients and 68 healthy subjects) and intron 14 T>C (in 99 stone patients and 56 healthy subjects) polymorphisms were determined using real-time polymerase chain reaction with TaqMan allelic discrimination method. There were no statistically significant differences in HGF intron 13 C>A and intron 14 T>C polymorphisms between the control and patient groups (X (2) = 1.72 df = 2; p = 0.42, and X (2) = 0.68 df = 2; p = 0.71, respectively). Mean serum HGF concentration was significantly lower in the stone disease patients than in the control subjects (1.05 ± 0.63 pg/mL and 1.35 ± 0.58 ng/mL respectively, p = 0.0001). When allele distribution frequency between stone patients and healthy subjects was compared, there were no significant differences in intron 13 and intron 14 allele distributions between two groups (p = 0.43 and p = 0.44, respectively). It may be concluded from the findings that decrease in HGF levels may play a role in renal stone formation, independent from gene polymorphisms.

Nanobacteria in the pathogenesis of urolithiasis: Myth or reality?

Stone formation in the urinary tract is a common phenomenon with associated morbidity. The exact physicochemical factors responsible for stone formation are not clearly known. Over the past decade considerable interest has been generated in defining the role of nanobacteria in urinary stone formation. A review of the available literature has been carried out to give insights into their nature and outline their role in stone formation. The two aspects of nanobacteria that need to be considered include its biological nature and the other merely as mineralo-protein complexes. Though the current literature favors the concept of mineralo-protein particles, further research is needed to clearly define their nature. Whether living or nonliving, these apatite forming nanoparticles appear to play role in kidney stone formation.

A whole genome SNP genotyping by DNA microarray and candidate gene association study for kidney stone disease

BACKGROUND

Kidney stone disease (KSD) is a complex disorder with unknown etiology in majority of the patients. Genetic and environmental factors may cause the disease. In the present study, we used DNA microarray to genotype single nucleotide polymorphisms (SNP) and performed candidate gene association analysis to determine genetic variations associated with the disease.

METHODS

A whole genome SNP genotyping by DNA microarray was initially conducted in 101 patients and 105 control subjects. A set of 104 candidate genes reported to be involved in KSD, gathered from public databases and candidate gene association study databases, were evaluated for their variations associated with KSD.

RESULTS

Altogether 82 SNPs distributed within 22 candidate gene regions showed significant differences in SNP allele frequencies between the patient and control groups (P < 0.05). Of these, 4 genes including BGLAP, AHSG, CD44, and HAO1, encoding osteocalcin, fetuin-A, CD44-molecule and glycolate oxidase 1, respectively, were further assessed for their associations with the disease because they carried high proportion of SNPs with statistical differences of allele frequencies between the patient and control groups within the gene. The total of 26 SNPs showed significant differences of allele frequencies between the patient and control groups and haplotypes associated with disease risk were identified. The SNP rs759330 located 144 bp downstream of BGLAP where it is a predicted microRNA binding site at 3'UTR of PAQR6 - a gene encoding progestin and adipoQ receptor family member VI, was genotyped in 216 patients and 216 control subjects and found to have significant differences in its genotype and allele frequencies (P = 0.0007, OR 2.02 and P = 0.0001, OR 2.02, respectively).

CONCLUSIONS

Our results suggest that these candidate genes are associated with KSD and PAQR6 comes into our view as the most potent candidate since associated SNP rs759330 is located in the miRNA binding site and may affect mRNA expression level.