Ethnicity-Specific Association Between Ghrelin Leu72Met Polymorphism and Type 2 Diabetes Mellitus Susceptibility: An Updated Meta-Analysis

Associations of PNPLA3 and LEP genetic polymorphisms with metabolic-associated fatty liver disease in Thai people living with human immunodeficiency virus

BACKGROUND

The prevalence of metabolic-associated fatty liver disease (MAFLD) is a growing public health issue in people living with human immunodeficiency virus (PLWH). However, the pathophysiology of MAFLD is still unknown, and the role of genetic variables is only now becoming evident.

AIM

To evaluate the associations of gene-polymorphism-related MAFLD in PLWH.

METHODS

The study employed transient elastography with a controlled attenuation parameter ≥ 248 dB/m to identify MAFLD in patients from a Super Tertiary Hospital in central Thailand. Candidate single-nucleotide polymorphisms (SNPs) were genotyped using TaqMan® MGB probe 5' nuclease assays for seven MAFLD-related genes. Statistical analyses included SNP frequency analysis, Fisher's Exact and Chi-square tests, odds ratio calculations, and multivariable logistic regression.

RESULTS

The G-allele carriers of PNPLA3 (rs738409) exhibited a two-fold rise in MAFLD, increasing by 2.5 times in MAFLD with human immunodeficiency virus infection. The clinical features and genetic patterns imply that LEP rs7799039 A-allele carriers had a nine times (P = 0.001) more significant chance of developing aberrant triglyceride among PLWH.

CONCLUSION

The current study shows an association between PNPLA3 rs738409 and LEP rs7799039 with MAFLD in PLWH.

Effect of the GHRL gene (rs696217) polymorphism on the metabolic disorders in patients with obesity in the Ukrainian population

Objective. Over the past four decades, the prevalence of obesity has tripled and limited genetic studies with specific SNPs have been conducted, but no investigations using ghrelin and obestatin prepropeptide (GHRL) gene have been reported in the Ukrainians population. The aim of this study was to evaluate changes in the level of metabolic hormones in the blood of obese patients in relation to the GHRL (rs696217) polymorphism. Methods. The study involved 53 obesity cases and 48 non-obesity subjects (controls). The GHRL (rs696217) polymorphism was genotyped using a TaqMan real-time polymerase chain reaction method. Blood hormones were determined with commercially available kits using a Multi-skan FC analyzer. Results. Carriers of the T allele of the GHRL (rs696217) polymorphism were statistically significantly more in patients diagnosed with obesity compared to controls indicating a genetically determined cause of obesity. We also established a significant effect of the presence of the T allele of the GHRL (rs696217) polymorphism on the decrease in the adiponectin level and the increase of resistin level in obese patients. The study of the effect of genotypes (TT, GT, GG) of the GHRL (rs696217) polymorphism on the metabolic hormone levels in the blood of obese patients did not show reliably significant differences. Conclusions. The presence of the T allele of the GHRL (rs696217) polymorphism in Ukrainian population indicates an increased risk of the obesity development regardless on the homozygous or heterozygous genotype.

Polymorphism of ghrelin genes among four Nigerian chicken populations as tool for improvement of chickens

Research on polymorphism of ghrelin (GHRL), an acylated peptide that stimulates the release of growth hormone from the pituitary, has shown that it is associated with some essential growth genes in chicken, hence veritable in genomic selection. There is porous information on the polymorphism of GHRL genes among Nigerian chickens. The objective of this study was to determine polymorphism of ghrelin gene among four Nigerian chicken populations. Blood sample (0.5 ml) was collected from the wing vein of 102 birds for DNA extraction. Tested PCR products were sequenced following Macrogen INC. The SNPs were determined using the sequence alignment program, CLUSTAL W, implemented in MEGA software. The sequence results showed 25 SNPs. The Nigerian chickens varied in polymorphic sites from Ogun chickens (348 and 535) to Nsukka chickens (558 and 696) at the GHRL 1 and GHRL2 loci respectively. Polymorphic sites and diversity were higher among the Nsukka chicken than other populations of the Nigerian chickens. SNPs common to one geographic varied in another. The result revealed that genomic selection based on ghrelin SNPs may yield higher predictive accuracy, while Nsukka chickens could be useful for the creation of more superior lines for the global poultry industry. Since past studies have revealed that ghrelin gene stimulates the pituitary and hypothalamus for releasing growth factor (GF) hormone and have strong effect on many organs, we suggest an association study of ghrelin gene and growth traits.

Dual Effect of the GHRL Gene Variant in the Molecular Pathogenesis of Obesity

Obesity is as a global health problem due to its interaction with complex chronic disorders such as cardiovascular disorders, type 2 diabetes mellitus (T2DM) and cancer. Despite the fact that pathogenesis of obesity is not yet clearly understood, it is associated with a combination of psychological, environmental and various genetic factors. Here, employing a case-control design, we aimed to examine the effects of the GHRL c.152C>T (p.Arg51Gln) (rs34911341) and c.214G>T (p.Leu72Met) (rs696217) markers on susceptibility to obesity in a Turkish-Cypriot population, as well as to evaluate whether these markers affect biochemical parameters and show their putative functional consequences. This study involved 211 Turkish-Cypriot subjects (106 obese and 95 non obese). Genotyping for the GHRL gene polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Our results indicate that the GHRL Leu72Met polymorphism was found to be significantly higher in obese patients, with respect to genotypic (p = 0.0012) and allelic (p = 0.0005) frequencies. Strikingly, the rs696217 GT genotype (heterozygous) had significantly lower serum high-density lipoprotein cholesterol (HDL-C) (p = 0.015) than GG (wild type) genotypes. Overall, Leu72Met susceptibility variant may be considered as risk and crucial marker for both obesity and cholesterol metabolism in the community of Turkish-Cypriots. Thus, the dual effect of the GHRL gene Leu72Met variant may be used for clinical diagnosis.

Leu72Met polymorphism of GHRL gene decreases susceptibility to type 2 diabetes mellitus in a Mexican population

BACKGROUND

Type 2 diabetes mellitus (T2D) is the most frequent type of diabetes. It has a multifactorial etiology, affecting millions of people worldwide. Ghrelin gene (GHRL) encodes the ghrelin peptide, which promotes food intake, induces body weight and adipogenesis. Several single nucleotide polymorphisms (SNPs) in GHRL gene have been associated with metabolic diseases. A protective effect of the Leu72Met (rs696217) polymorphism has been described for T2D in some populations, but this effect seems to depend on the ethnicity of the patients studied.

METHODS

The aim of this study was to investigate the association between the GHRL Leu72Met (rs696217) SNP with the development of T2D and serum ghrelin levels in a Western Mexican population. We performed a case-control study in which we included 284 subjects (159 with previous T2D diagnosis and 125 control subjects (CS)). Leu72Met SNP was genotyped by using PCR-RFLPs technique. Serum ghrelin levels were measured using a commercial enzyme immunoassay. Genotypic and allelic distributions were compared using Chi square test. Student T-test and Mann-Whitney U test were used to compare quantitative variables. Odds ratio (OR) was used to evaluate the association between alleles or genotypes and T2D. Multiple and logistic regression models were performed for adjustment. A two-tailed p-value ≤0.05 was considered statistically significant.

RESULTS

Leu72Leu genotype was more frequent among T2D compared to CS (p < 0.05). After adjusting for age and body composition, there was a significant protective effect of the 72Met allele for T2D development (OR 0.40 IC 95% 0.23-0.70; p ≤ 0.001). Fasting serum ghrelin levels were lower in T2D than CS (p ≤ 0.0001) irrespective of age, body weight and BMI. No associations were found between genotypes and ghrelin serum levels in our population.

CONCLUSIONS

The GHRL 72Met allele decreases susceptibility for T2D development in a Western Mexican population. Serum ghrelin levels are lower in T2D independently of Leu72Met polymorphism genotype.