The Deletion Polymorphism in Exon 8 of Uncoupling Protein 2 is Associated with Severe Obesity in a Saudi Arabian Case-control Study

Prevalence, risk factors, and interventions for obesity in Saudi Arabia: A systematic review

Saudi Arabia (SA) has a reported obesity prevalence greater than the global average. Here, we systematically review firstly the prevalence and associated factors (59 studies) and secondly the pharmacological, lifestyle, and surgical interventions for obesity (body mass index, >30 kg/m² ) in SA (29 studies) between December 2020 and March 2021 in PubMed, Medline, Embase, PsycINFO, and Cochrane. Peer-reviewed articles in Arabic and English on human adults (aged >18 years) were searched. Among the eight largest studies with sample sizes over 10,000 people, the maximum-reported obesity prevalence was 35.6%, with notable variations in gender and geographic region. Diet, specifically the move towards Western diet and heavy consumption of sugary beverages, and high levels of inactivity are major contributing factors to obesity. The reported obesity-risk polymorphisms are not specific. Bariatric surgery is underrepresented, and in general, there is a lack of nationally coordinated studies on weight loss interventions. In particular, the systematic review did not find a body of research on psychological interventions. There is no trial data for the use of GLP-1 analogs in SA, despite their widespread use. These findings can help policymakers, and practitioners prioritize future research efforts to reduce obesity prevalence in SA.

Association and interaction effect of UCP2 gene polymorphisms and dietary factors with congenital heart diseases in Chinese Han population

Congenital heart diseases (CHDs) are the most common birth defects and the leading cause of non-infectious deaths in infants, with an unknown etiology. We aimed to assess the association of genetic variations in UCP2 gene, dietary factors, and their interactions with the risk of CHDs in offspring. The hospital-based case–control study included 464 mothers of children with CHDs and 504 mothers of healthy children. The exposures of interest were maternal dietary factors in early pregnancy and UCP2 genetic variants. Logistic regression analyses were used to assess the association and interaction of UCP2 gene and dietary factors with CHDs. Our results found that the polymorphisms of UCP2 gene at rs659366 and rs660339, together with maternal dietary factors including excessive intake of pickled vegetables and smoked foods were associated with increased risks of CHDs in offspring. Regular intake of fresh meat, fish and shrimp, and milk products were associated with lower risks of CHDs in offspring. Besides, positive interaction between the dominant model of rs659366 and excessive intake of pickled vegetables was found in the additive interaction model (RERI = 1.19, P = 0.044). These findings provide the theoretical basis for gene screening and a new clue for the prevention of CHDs in offspring.

Genetic polymorphisms associated with obesity in the Arab world: a systematic review

BACKGROUND

Obesity, one of the most common chronic health conditions worldwide, is a multifactorial disease caused by complex genetic and environmental interactions. Several association studies have revealed a considerable number of candidate loci for obesity; however, the genotype-phenotype correlations remain unclear. To date, no comprehensive systematic review has been conducted to investigate the genetic risk factors for obesity among Arabs.

OBJECTIVES

This study aimed to systematically review the genetic polymorphisms that are significantly associated with obesity in Arabs.

METHODS

We searched four literature databases (PubMed, Science Direct, Scopus, and Google Scholar) from inception until May 2020 to obtain all reported genetic data related to obesity in Arab populations. Quality assessment and data extraction were performed individually by three investigators.

RESULTS

In total, 59 studies comprising a total of 15,488 cases and 9,760 controls were included in the systematic review. A total of 76 variants located within or near 49 genes were reported to be significantly associated with obesity. Among the 76 variants, two were described as unique to Arabs, as they have not been previously reported in other populations, and 19 were reported to be distinctively associated with obesity in Arabs but not in non-Arab populations.

CONCLUSIONS

There appears to be a unique genetic and clinical susceptibility profile of obesity in Arab patients.

Frequency of UCP2 45-bp Ins/Del polymorphism in Saudi population from Jazan area and its association with autoimmune hypothyroidism UCP2 45-bp Ins/Del frequency in hypothyroidism

OBJECTIVES

Autoimmune hypothyroidism (AHT) is a common endocrine disorder. Although the exact cause of AHT is not yet understood, genetic factors may play a major role. Uncoupling protein 2 (UCP2) is a member of mitochondrial protein family involved in the regulation of cellular metabolism. An important functional polymorphism in the UCP2 gene, 45-bp insertion/deletion (ins/del) polymorphism, has been linked to certain clinical conditions. However, an association between the 45-bp ins/del polymorphism and AHT has not yet been established.

METHODS

In this study, about 259 blood samples were collected from, patients with AHT and age-matched healthy control subjects. DNA was extracted for UCP2 45-bp ins/del polymorphisms genotyping, using a standard polymerase chain reaction technique. The distribution of different genotypes was determined in both groups and possible association with AHT was also assessed by logistic regression analysis using the Del/Del variant as a reference genotype.

RESULTS

The frequency of the UCP2 45-bp ins/del polymorphism in the total study population was 49.04%, 40.15%, and 10.81% for Del/Del, Ins/Del, and Ins/Ins genotypes, respectively. The logistic regression analysis showed crude odds ratios (ORs), respectively, with their 95% confidence intervals (CIs) and P-values in codominant (Del/Ins) (OR = 1.53, CI = 0.89-2.60, P = 0.17), codominant (Ins/Ins) (OR = 0.75, CI = 0.34-1.74, P = 0.53), dominant (OR = 1.30, CI = 0.79-2.16, P = 0.37), and recessive (OR = 0.62, CI = 0.29-1.36, P = 0.30) inheritance models tested, where none of which were statistically significant.

CONCLUSION

Our data revealed the distribution of the UCP2 45-bp ins/del polymorphisms in Jazan area and confirmed the lack of association between these genetic variants and the development of AHT.

UCP2 gene polymorphisms in obesity and diabetes, and the role of UCP2 in cancer

Mitochondria are the primary sites for ATP synthesis and free radical generation in organisms. Abnormal mitochondrial metabolism contributes to many diseases, including obesity, diabetes and cancer. UCP2 is an ion/anion transporter located in mitochondrial inner membrane, and has a crucial role in regulating oxidative stress, cellular metabolism, cell proliferation and cell death. Polymorphisms of the UCP2 gene have been associated with diabetes and obesity because UCP2 is involved in energy expenditure and insulin secretion. Moreover, UCP2 gene expression is often amplified in cancers, and increased UCP2 expression contributes to cancer growth, cancer metabolism, anti-apoptosis and drug resistance. The present review summarizes the latest findings of UCP2 with respect to obesity, diabetes and cancer.

Uncoupling Protein 2 (UCP2) as Genetic Risk Factor for Obesity in Indonesia is Different in Gender Stratification

Ala55Val and 45 basepair (bp) insertion/deletion (I/D) of UCP2 gene polymorphisms cause a decrease in resting energy expenditure, decreasing fatty acid oxidation and influencing mRNA transcription and stability, thereby increasing the risk of obesity. The purpose of this study was to determine the role of Ala55Val and 45 bp I/D polymorphisms of the UCP2 gene as a risk factor for obesity. This study consisted of 200 Indonesian subjects of Javanese ethnicity consisting of 100 obese and 100 non-obese participants. Examination of Ala55Val (C > T) UCP2 genotype used Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) methods and 45 bp I/D genotype used PCR methods. Polymorphism of Ala55Val UCP2 genotype in the male group showed that TT genotype and T allele significantly lowers the risk of obesity. Insertion/deletion of 45 bp UCP2 gene in the male group showed that II genotype and I allele significantly increase the risk of obesity whereas for women it showed that the DI genotype and I allele lower the risk of obesity. The results of this study demonstrate that Ala55Val and 45 bp I/D UCP2 polymorphisms play a role in the risk of obesity in Javanese ethnicity of Indonesia after gender stratification.