Association of genetic variants of ghrelin, leptin and UCP2 with malnutrition inflammation syndrome and survival in end-stage renal disease patients

Potential protective effect of leptin and uncoupling protein-2 genes polymorphism in Egyptian patients with chronic kidney disease

BACKGROUND

Kidney disease is a serious public health problem worldwide. It is the fifth top-ranking cause of death in Egypt, causing approximately 3.98% of all deaths. This study's objective was to examine whether an association exists between leptin (- 2548G/A) and uncoupling protein-2 45 bp I/D genes, individually and collectively, in CKD and progression to ESRD.

METHODS

One hundred patients (69 males, 31 females) aged (47.1 ± 16.11 years) with ESRD, 40 patients (19 males, 21 females) aged (43.15 ± 10.00 years with CKD, and 50 healthy controls (23 males, 27 females) aged (37.84 ± 1.95 years) were enrolled. Polymerase chain reaction (PCR) was employed to measure variation in gene expression among the study groups. The frequency of single nucleotide polymorphisms (SNP) genotypes were identified in controls, CKD and ESRD patients.

RESULTS

Leptin genotypes were associated with lower CKD incidence in control versus study subjects (95% CI = (0.08-0.63), P = 0.01) with risk value equal to 0.22 < 1, G/A genotype was significantly lower in CKD than ESRD groups. There was no correlation between UCP-2 I/D genotype and CKD (P = 0.27). There was no correlation between the UCP-2 gene and the progression to ESRD.

CONCLUSIONS

This study suggests that, Leptin - 2548G/A gene may be a promising marker for early detection of ESRD in Egyptian patients. G/A genotype might inhibit the development of CKD to ESRD.

Leptin and ghrelin in chronic kidney disease: their associations with protein-energy wasting

BACKGROUND

This study aimed to evaluate plasma concentrations of leptin and total ghrelin in children with chronic kidney disease (CKD) and assess their roles in protein-energy wasting (PEW).

METHODS

This study consisted of three different CKD populations [CKD group (20 patients with non-dialysis CKD), dialysis group (39 patients on dialysis), and kidney transplant (KTx) group (35 KTx recipients)] and control group (18 healthy children). Plasma leptin and total ghrelin levels were measured. Multi-frequency bioimpedance analysis was used for the assessment of fat and lean mass. PEW was defined using criteria including body mass, muscle mass, growth, serum albumin level, and protein intake.

RESULTS

While plasma leptin levels did not differ among the study groups, total ghrelin levels were significantly higher in the dialysis group (P < 0.001). Seven dialysis patients (18%) and one CKD patient (5%) but none of the KTx recipients met the criteria of PEW. Dialysis patients with PEW had lower plasma leptin levels compared to their counterparts (P = 0.018); however, total ghrelin levels did not differ between the two groups (P = 0.10). Low leptin level in dialysis patients was independently associated with lower fat mass index (P < 0.001) and lower height-specific SD scores of BMI (P = 0.019).

CONCLUSIONS

PEW is prevalent in dialysis patients. Low levels of leptin seem to be associated with PEW. Our result suggests that low leptin levels may be a consequence rather than a cause of PEW. Longitudinal studies are required to investigate this complex relationship between leptin and PEW in pediatric dialysis patients.

Association between leptin gene rs7799039 polymorphism and lipid profile changes induced by isotretinoin treatment in acne patients

Introduction

Isotretinoin, a vitamin A-derived medication, is one of the effective treatments for severe acne. However, in a fraction of patients, this treatment causes significant adverse effects. Leptin is a pro-inflammatory cytokine that plays a role in apoptosis of adipose cells and sebaceous lipid metabolism. Thus, genetic polymorphisms in the leptin (LEP) gene may modulate the response to isotretinoin therapy. Here, we explore the contribution of rs7799039 polymorphism of the LEP gene in the adverse effects of the oral isotretinoin therapy among acne patients.

Materials and methods

Clinical parameters were obtained from 200 patients before and after isotretinoin treatment for acne. In addition, circulatory lipid profile and aspartate transaminase (AST) and alanine aminotransferase (ALT) enzymes from acne subjects before and 1 month after oral isotretinoin treatment were also measured.

Results

An association between the rs7799039 polymorphism and the following lipid parameters: high-density lipoprotein (HDL) at baseline and after treatment, HDL % change, low-density lipoprotein % change and total cholesterol % change (P < 0.05). In addition, there was an association between the LEP polymorphism and higher AST and ALT at baseline and after treatment (P < 0.05).

Conclusion

In conclusion, rs7799039 LEP polymorphism might modulate lipid parameters and liver enzymes, but not other major side effects of oral isotretinoin therapy.

Ghrelin and the Cardiovascular System

Ghrelin is a small peptide released primarily from the stomach. It is a potent stimulator of growth hormone secretion from the pituitary gland and is well known for its regulation of metabolism and appetite. There is also a strong relationship between ghrelin and the cardiovascular system. Ghrelin receptors are present throughout the heart and vasculature and have been linked with molecular pathways, including, but not limited to, the regulation of intracellular calcium concentration, inhibition of proapoptotic cascades, and protection against oxidative damage. Ghrelin shows robust cardioprotective effects including enhancing endothelial and vascular function, preventing atherosclerosis, inhibiting sympathetic drive, and decreasing blood pressure. After myocardial infarction, exogenous administration of ghrelin preserves cardiac function, reduces the incidence of fatal arrhythmias, and attenuates apoptosis and ventricular remodeling, leading to improvements in heart failure. It ameliorates cachexia in end-stage congestive heart failure patients and has shown clinical benefit in pulmonary hypertension. Nonetheless, since ghrelin's discovery is relatively recent, there remains a substantial amount of research needed to fully understand its clinical significance in cardiovascular disease.

The association of uncoupling protein 2 (UCP2) exon 8 insertion/deletion polymorphism and ECG derived QRS duration: A cross-sectional study in an Australian rural population

BACKGROUND

Associations between inherited mitochondrial disease and cardiac conduction have been previously described. However, there are no available studies exploring the mitochondrial uncoupling protein 2 gene (UCP2) insertion/deletion (I/D) polymorphisms interaction on cardiac electrical conduction. Our aim was to determine if ECG-derived QRS duration is associated with UCP2 DD genotype in a cross-sectional Australian aging rural population.

METHODS

A retrospective study design utilizing a rural health diabetic screening clinic data-base containing observational data from September 2011 to September 2014. Inclusion criteria included were having ECG parameters such as QRS duration measures and a DNA sample within the same subject. Genomic DNA was extracted and subjects were genotyped for the 45-bp I/D polymorphism in the 3'-untranslated region of UCP2.

RESULTS

281 individuals were available for analysis. On the basis of QRS duration >140ms we found an increased percentage of our population with DD homozygotes, compared to ID heterozygotes and II homozygotes (p=0.047). For other ECG parameters; mean PQ duration, QTc across UCP2 genotypes was not significant (p=NS). QTc using a cut-off >440ms in contingency table analysis revealed no significant differences across UCP2 I/D genotypes. Mean QT dispersion (QTd) was paradoxically less in the UCP2 DD genotype compared to UCP2 II subgroup (p=0.034).

DISCUSSION

We have demonstrated an association between increasing ECG-derived QRS duration >140ms and the UCP2 DD polymorphism. The lack of association with ECG derived QTd and UCP2 DD may suggest that gene-related QRS duration prolongation is independent of cardiac hypertrophy.

A 45-bp insertion/deletion polymorphism of UCP2 gene is associated with metabolic syndrome

Background

Metabolic syndrome (MeS) is being recognized as a risk factor for insulin resistance and cardiovascular disease. The present study was aimed to find out the possible association between 45-bp I/D polymorphism of uncoupling protein 2 (UCP2) and MeS.

Methods

DNA was extracted from peripheral blood of 151 subjects with and 149 subjects without MeS. 45-bp I/D variant of UCP2 was detected using polymerase chain reaction (PCR).

Results

Our finding showed that 45-bp I/D polymorphism was associated with protection against MeS (OR = 0.56, 95% CI = 0.34-0.92, p = 0.020 D/I vs DD and OR = 0.54, 95% CI = 0.34-0.86, p = 0.009; D/I + I/I vs D/D). The I allele decreased the risk of MeS (OR = 0.62, 95% CI = 0.44-0.90, p = 0.011) in comparison with D allele.

Conclusion

In conclusion, our result suggests that 45-bp I/D polymorphism is associated with the risk of MeS, which remains to be cleared.