Mitochondrial DNA haplogroups and risk of new-onset diabetes among tacrolimus-treated renal transplanted patients

Background and aims

Tacrolimus (Tac) is an immunosuppressive drug widely used to avoid organ rejection. New-onset diabetes after transplantation (NODAT) is a major complication among transplanted patients who receive Tac. The increased risk for NODAT could be partly mediated by the effect of Tac on mitochondria from pancreatic beta-cells. Common and rare mitochondrial DNA variants have been linked to the risk of diabetes. Our aim was to determine whether mtDNA polymorphisms/haplogroups were associated with NODAT in Tac-treated kidney transplanted.

Methods

Seven polymorphisms that define the common European haplogroups were determined in 115 NODAT and 197 no-NODAT patients.

Results

Haplogroup H was significantly more frequent in the NODAT group (50% vs. 35%; p = 0.01, OR = 1.82). There was no difference between patients without and with (n = 106) D2M prior to the transplant.

Conclusions

Mitochondrial haplogroup H was associated with the risk for NODAT among Tac-treated transplanted patients. The reported differences between the mtDNA variants could explain the increased NODAT-risk among H-patients.     

Variants of NLRP3 gene are associated with insulin resistance in Chinese Han population with type-2 diabetes

Aims

Nod like receptor pyrin domain containing 3 (NLRP3) is the best characterized member of nod like receptor family. Recent studies suggest that NLRP3 plays a crucial role in the pathogenesis of type-2 diabetes (T2DM), and variants in NLRP3 affect its mRNA stability and expression. Therefore, we hypothesize that the variants in NLRP3 gene may contribute to T2DM susceptibility. The aim of this study is to evaluate the association of NLRP3 SNPs with T2DM in Chinese Han patients.

Methods

Two common variants in NLRP3 gene, rs10754558 and rs4612666, were detected using the polymerase chain reaction–restriction fragment length polymorphism procedure in 952 unrelated T2DM patients and 871 healthy controls. All participants were unrelated Chinese Hans.

Results

The GG genotype and G allele frequencies of rs10754558 were significantly higher in T2DM patients than those in controls (for GG genotype, 19.6% vs. 14.5%, p = 0.019; for G allele, 43.9% vs. 39.8%, p = 0.013). The GG genotype of rs10754558 was significantly associated with higher LDL-C levels and more prone to insulin resistance, as evaluated by HOMA-IR or QUICK indexes.

Conclusions

The variant (rs10754558) in NLRP3 is related to insulin resistance and increased risk of T2DM in Chinese Han population.     

Association of ghrelin Leu72Met polymorphism with type 2 diabetes mellitus in Chinese population

Background

Ghrelin, a novel endogenous ligand for the growth hormone secretagogue receptor, is considered to implicate the development of the type 2 diabetes mellitus (T2DM). The Leu72Met (+ 408 C > A) polymorphism of the preproghrelin, has been linked to obesity, insulin resistance and diabetes.

Objective

To investigate the distribution of ghrelin gene Leu72Met polymorphism and its association with the type 2 diabetes mellitus in Chinese population.

Methods

We conducted a case–control study on 877 patients with T2DM and 864 controls, which were genotyped by the polymerase chain reaction (PCR) technique, denaturing high performance liquid chromatography (DHPLC) and DNA sequence analysis. Laboratory analyses were carried out in the hospital laboratory.

Results

No significant difference in the Leu72Met genotype distributions and allele frequency was observed between type 2 diabetes mellitus and controls (both P > 0.05). The polymorphism was not associated with T2DM. However, among the T2DM group, the patients carrying Leu72Leu genotype had significantly increased levels of FPG and serum creatinine compared with variant genotypes (Leu72Met and Met72Met) (P < 0.05). In the control group, the subjects with variant genotypes had significantly increased levels of FINS, HOMA-IR compared with Leu72Leu genotype (P < 0.05).

Conclusion

The Leu72Met polymorphism of the preproghrelin gene was not associated with T2DM in Chinese population. However, it may have some roles in the etiology of insulin resistance.     

Mitochondrial DNA haplogroup Y is associated to Leigh syndrome in Chinese population

Although Leigh syndrome (LS) is a well characterized clinical mitochondrial disorder; the exact mutation is not found in all cases and it is not clear whether matrilineal background has contributed to this disease. To address this issue, we extensively studied and compared the haplogroup composition of a sample of 171 Chinese LS patients with that of 1597 controls. Our results show that haplogroup Y may increase the risk of LS in Chinese by 2.867 fold (95% CI = 1.135–7.240, P = 0.020). Haplogroup B5 has also this trend (1.737 fold, 95% CI = 0.961–3.139), but with a borderline P-value (P = 0.065). Both haplogroups belong to macro-haplogroup N and share a common reverse mutation on nucleotide position 10398 (A10398G). In fact, the combined haplogroup N with 10398G is also associated with an increased risk for LS (OR = 1.882, 95% CI = 1.134–3.124, P = 0.013).     

Association of P213S polymorphism of the L-selectin gene with type 2 diabetes and insulin resistance in Chinese population

Aims

L-selectin belongs to selectin family of adhesion molecule and participates in the generation and development of type 2 diabetes (T2D). In this study, we evaluated the relationship between the P213S polymorphism of L-selectin gene and T2D and insulin resistance in the Chinese population.

Methods

We genotyped P213S polymorphism in 801 patients with T2D and 834 healthy controls in the Chinese population using polymerase chain reaction–ligase detection reaction (PCR–LDR) technique. Plasma glucose, insulin, lipid, blood urea nitrogen, creatinine and uric acid levels were measured by biochemical technique.

Results

The frequency of 213PP genotype and P allele of the L-selectin gene in patients with T2D was significantly higher than that in controls (P = 0.007; P = 0.019, respectively). The relative risk of allele P suffered from T2D was 1.191 times higher than that of allele S. Moreover, the levels of FPG and HOMA-IR of PP and PS genotype carriers were significantly higher than those of SS genotype carriers in the T2D group (P < 0.05).

Conclusion

These findings indicated that the P213S polymorphism of L‐selectin gene may contribute to susceptibility to T2D and insulin resistance in the Chinese population, and P allele appears to be a risk factor for T2D.