Leptin gene polymorphism (rs 7799039;G2548A) is associated with changes in lipid profile during a partial meal-replacement hypocaloric diet

The impact of leptin and its receptor polymorphisms on type 1 diabetes in a population of northwest Iran

BACKGROUND

Diabetes comprises a serious disease with significant growth in the number of cases in recent years. Here, we cover the gap in information between leptin (LEP) and type 1 diabetes in the Iranian population.

AIM

To recognise LEP G2548A and LEP receptor Q223R polymorphisms in Iranian people and their association with type 1 diabetes susceptibility.

SUBJECTS AND METHODS

Characteristics such as fasting blood sugar (FBS) were measured in 80 control non-diabetic individuals and 89 diabetic patients. Moreover, LEP G2548A and LEP receptor Q223R polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism technique.

RESULTS

The frequency of the A allele was nearly three times greater in diabetes patients than in the control group. In addition, in the diabetes group, the AA genotype was five times greater than in the control group (p < 0.01). Furthermore, AA and AA + AG genotype models had higher FBS levels than the GG + AG and GG genotype models, respectively (p < 0.01).

CONCLUSION

The LEP G2548A polymorphism could be related to type 1 diabetes susceptibility, but not LEPR Q223R polymorphism in the Iranian population. Importantly, further studies are essential to examine the impact of LEP G2548A and LEPR Q223R polymorphisms in the endocrinology area.

Gene polymorphism of leptin and risk for heart disease, obesity, and high BMI: a systematic review and pooled analysis in adult obese subjects

Objectives

Leptin polymorphism (LEP) has been associated with coronary heart disease (CAD), obesity, and high body mass index (BMI). However, we performed a systematic review and meta-analysis to discover the association because previous studies reached different conclusions.

Methods

Review Manager, version 5.3.5, and Stata, version 15.0, were used for statistical analysis. We calculated the effect size of the studies using the OR with the corresponding 95% CI, and two-sided (bilateral) p-values of 0.05 were considered significant. To determine heterogeneity among the selected studies, the Q test and I2 statistics were used. Meta-regression was used to examine the disease (heart disease, obesity, and high BMI) and heterogeneity between these subgroups.

Results

Eleven studies with 18,984 subjects were included in this study. The G-2548A (rs12112075), rs7799039, and A19G (rs2167270) polymorphisms of the leptin gene (but not the Lys656Asn (rs1805094) polymorphism) are associated with an increased risk of cardiovascular disease. Our pooled analysis revealed an association between the G-2548A (rs12112075) polymorphism and heart disease, high BMI, and obesity. This indicates that individuals carrying the AA allele are at an increased risk for heart disease, high BMI, and obesity. People with heart failure and coronary artery disease did not have the rs7799039 polymorphism or its alleles linked to them.

Conclusions

Combined analysis of data from current and published research suggests that the leptin gene polymorphisms G-2548A (rs12112075), rs7799039, and A19G (rs2167270) (but not the Lys656Asn (rs1805094) polymorphism) are associated with an increased risk of cardiovascular disease. Further research is needed to understand this association.

Early and Strong Leptin Reduction Is Predictive for Long-Term Weight Loss during High-Protein, Low-Glycaemic Meal Replacement-A Subanalysis of the Randomised-Controlled ACOORH Trial

Lifestyle interventions including meal replacement are suitable for prevention and treatment of obesity and type-2-diabetes. Since leptin is involved in weight regulation, we hypothesised that a meal replacement-based lifestyle intervention would reduce leptin levels more effectively than lifestyle intervention alone. In the international, multicentre, randomised-controlled ACOORH-trial (Almased-Concept-against-Overweight-and-Obesity-and-Related- Health-Risk), overweight or obese participants with metabolic syndrome criteria (n = 463) were randomised into two groups and received telemonitoring devices and nutritional advice. The intervention group additionally used a protein-rich, low-glycaemic meal replacement. Data were collected at baseline, after 1, 3, 6, and 12 months. All datasets providing leptin data (n = 427) were included in this predefined subanalysis. Serum leptin levels significantly correlated with sex, body mass index, weight, and fat mass at baseline (p < 0.0001). Stronger leptin reduction has been observed in the intervention compared to the control group with the lowest levels after 1 month of intervention (estimated treatment difference −3.4 µg/L [1.4; 5.4] for females; −2.2 µg/L [1.2; 3.3] for males; p < 0.001 each) and was predictive for stronger reduction of body weight and fat mass (p < 0.001 each) over 12 months. Strongest weight loss was observed after 6 months (−5.9 ± 5.1 kg in females of the intervention group vs. −2.9 ± 4.9 kg in the control group (p < 0.0001); −6.8 ± 5.3 kg vs. −4.1 ± 4.4 kg (p = 0.003) in males) and in those participants with combined leptin and insulin decrease. A meal replacement-based lifestyle intervention effectively reduces leptin which is predictive for long-term weight loss.

Leptin Signaling in Obesity and Colorectal Cancer

Obesity and colorectal cancer (CRC) are among the leading diseases causing deaths in the world, showing a complex multifactorial pathology. Obesity is considered a risk factor in CRC development through inflammation, metabolic, and signaling processes. Leptin is one of the most important adipokines related to obesity and an important proinflammatory marker, mainly expressed in adipose tissue, with many genetic variation profiles, many related influencing factors, and various functions that have been ascribed but not yet fully understood and elucidated, the most important ones being related to energy metabolism, as well as endocrine and immune systems. Aberrant signaling and genetic variations of leptin are correlated with obesity and CRC, with the genetic causality showing both inherited and acquired events, in addition to lifestyle and environmental risk factors; these might also be related to specific pathogenic pathways at different time points. Moreover, mutation gain is a crucial factor enabling the genetic process of CRC. Currently, the inconsistent and insufficient data related to leptin's relationship with obesity and CRC indicate the necessity of further related studies. This review summarizes the current knowledge on leptin genetics and its potential relationship with the main pathogenic pathways of obesity and CRC, in an attempt to understand the molecular mechanisms of these associations, in the context of inconsistent and contradictory data. The understanding of these mechanisms linking obesity and CRC could help to develop novel therapeutic targets and prevention strategies, resulting in a better prognosis and management of these diseases.