Serum Fibroblast Growth Factor 23 and FGF23 Gene Variants in Patients with Type 2 Diabetes and Essential Hypertension. Association with Chronic Kidney Disease

Single Nucleotide Variants of the SLC2A9 Gene are Associated With Hyperuricemia in Mexican Patients With Type 2 Diabetes

BACKGROUND

Chronic kidney disease (CKD) due to diabetes is the third leading cause of death in Mexico. A relationship between high serum uric acid (SUA) levels and kidney disease have been demonstrated. On the other hand, variants of the SLC2A9 gene have been associated with elevated SUA concentrations. This study evaluated the associations of the rs11722228, rs3775948, rs7678287, and rs1014290 variants with hyperuricemia and biochemical parameters in patients with type 2 diabetes (T2D).

METHODS

The study included 1036 Mexican subjects with T2D. Patients were grouped based on the presence (n = 462) or absence (n = 574) of diabetic kidney disease (DKD). SUA concentrations and biochemical parameters were determined. Samples were genotyped through real-time polymerase chain reaction. Associations between genetic variants and hyperuricemia were analyzed by univariate and multivariate models adjusting for covariates.

RESULTS

SUA levels and hyperuricemia prevalence were higher in the DKD group. rs3775948 and rs1014290 showed negative associations with hyperuricemia in the whole sample and in patients without DKD. rs7678287 was positively correlated with SUA and hyperuricemia in patients without DKD, whereas rs11722228 was a risk factor only in the DKD group. The presence of DKD and elevated triglycerides and total cholesterol were significant factors associated with hyperuricemia.

CONCLUSIONS

Variants rs3775948 and rs1014290 exhibit protective effects, while rs7678287 and rs11722228 may confer increased risk of hyperuricemia in Mexican patients with T2D. Analysis of SLC2A9 gene variants could help in detecting patients at increased risk of kidney or cardiovascular complications due to hyperuricemia.

Association of KLOTHO gene variants with metabolic and renal function parameters in Mexican patients living with type 2 diabetes

Objective

Type 2 diabetes (T2D) and high blood pressure are the main causes of chronic kidney disease (CKD) in adulthood. Both metabolic and oxidative stresses driven by hyperglycemia as well as genetic factors have been suggested as pathogenic causes of renal failure. Some single nucleotide variants (SNVs) on gene coding KLOTHO (KL) have been implicated in several clinical scenarios including hypertension, diabetes, and cardiovascular disease. The aim of this study was to analyze the association of rs1207568 (-395G > A), rs953614 (+ 1062T > G) and rs564481 (+ 1818 C > T) SNVs with metabolic and renal function parameters in Mexican patients living with type 2 diabetes.

Methods

A cross-sectional study was conducted in 637 Mexican patients with T2D, and/or hypertension without previous diagnosis of CKD. Anthropometric, metabolic, and renal function parameters were determined. Patients were genotyped for rs1207568, rs953614 and rs564481 SNVs and associations under a dominant genetic model were analyzed by logistic regression.

Results

For rs9536314, G-allele showed to be protective for hypo-HDL-C, albuminuria, and CKD. Carriers of minor allele of rs564481 had low odds for high glucose levels. No differences in genotype nor allele frequencies between the patients and the reference population were observed.

Conclusion

In Mexican patients living with type 2 diabetes, KL variant rs9536314 was found associated with low odds of hypo-HDL cholesterol, albuminuria and presence of CKD. Meanwhile the consensus of soluble KLOTHO measurement is reached, genetic variants in the KL gene could be considered as genetic markers for CKD susceptibility in patients at high-risk of vascular complications.

Decreased FGF23 inhibits placental angiogenesis via the ERK1/2-EGR-1 signaling pathway in preeclampsia

PURPOSE

This study aimed to investigate the expression of fibroblast growth factor 23 (FGF23) in pregnant women with preeclampsia and elucidate its role in promoting placental angiogenesis through the ERK1/2-EGR-1 signaling pathway.

METHODS

Serum FGF23 levels were measured by ELISA in healthy pregnant women and patients with preeclampsia during the first, second, and third trimesters of pregnancy. Wound healing, Transwell, and tube formation assays were performed to investigate the effects of FGF23 on cell migration, invasion and tube formation. The expression of vascular endothelial growth factor A (VEGF-A) and its upstream signaling molecules, p-ERK, and EGR-1, in placental tissues was detected by RT-qPCR and western blotting. Additionally, the effect of FGF23 on VEGF-A, p-ERK, and EGR-1 expression was further explored in vitro.

RESULTS

Serum FGF23 levels increased with gestational age. During the third trimester, the control group exhibited a more pronounced increase in FGF23 levels than the preeclampsia group. Administering exogenous FGF23 promoted trophoblast cell migration, invasion and enhanced tube formation in vascular endothelial cells. The expression levels of VEGF-A, p-ERK, and EGR-1 in the placental tissues were significantly lower in the preeclampsia group than in the control group. In vitro experiments confirmed that FGF23 up-regulated VEGF-A expression through the p-ERK/EGR-1 signaling pathway.

CONCLUSION

The serum level of FGF23 decreased in pregnant women with preeclampsia, inhibiting the ERK1/2-EGR-1 pathway and resulting in decreased expression of VEGF-A, thereby inhibiting placental angiogenesis. This could be a potential mechanism involved in the progression of preeclampsia.