BackgroundAlthough the exact mechanism of insulin resistance (IR) has not yet been established, IR is the hallmark characteristic of type 2 diabetes mellitus (T2DM). The aim of this study was to examine the relationship between plasma ghrelin levels and IR in Saudi subjects with T2DM.MethodsPatients with T2DM (n=107, cases) and non-diabetic apparently healthy subjects (n=101, controls) from Saudi Arabia were included in this study. The biochemical profiles and plasma insulin levels of all subjects were analyzed, and IR was estimated using the homeostatic model assessment of insulin resistance (HOMA-IR) index. Active ghrelin levels in plasma were measured using the radioimmunoassay technique.ResultsOnly 46.7% (50 of 107) of the T2DM subjects had IR, including 26% (28 of 107) with severe IR (HOMA-IR ≥5), while 5.9% (six of 101) of the controls had moderate IR (3 ≤HOMA-IR <5). HOMA-IR values were not associated with age, disease duration, or gender. Importantly, T2DM itself and the co-occurrence of IR with T2DM were significantly associated with low plasma ghrelin levels. However, ghrelin levels were inversely correlated with the HOMA-IR index, body weight, and fasting plasma insulin levels, mainly in the control subjects, which was indicative of the breakdown of metabolic homeostasis in T2DM.ConclusionThe prevalence of IR was relatively low, and IR may be inversely associated with plasma ghrelin levels among Saudi patients with T2DM.

BackgroundGhrelin (GHRL), a gastric peptide encoded by the GHRL gene, is known to be involved in energy homeostasis via its G protein receptor, encoded by the growth hormone secretagogue receptor (GHSR) gene. Some studies have shown associations between plasma GHRL levels and GHRL single-nucleotide polymorphisms (SNPs), namely the Leu72Met polymorphism (rs696217 TG), with type 2 diabetes mellitus (T2DM) and insulin resistance (IR), while others have not. The controversies in these associations raise the issue of ‘which SNPs in which populations.’ The aim of this study was to investigate whether SNPs in GHRL and/or GHSR genes were associated with T2DM, IR, or plasma GHRL levels among Arab Saudis.MethodsBlood was collected from 208 Saudi subjects with (n=107) and without (n=101) T2DM. DNA samples from these subjects were analyzed by real-time polymerase chain reaction to genotype five intronic SNPs in the GHRL (rs696217 TG, rs27647 CT, rs2075356 CT, and rs4684677 AT) and GHSR (rs509030 GC) genes. In addition, plasma GHRL levels were measured by a radioimmunoassay.ResultsNone of the SNPs were associated with T2DM, IR, or plasma GHRL levels. The frequencies of the alleles, genotypes, and haplotypes of the five SNPs were comparable between the T2DM patients and the non-diabetic subjects. A large number of the GHRL haplotypes indicates the molecular heterogeneity of the preproghrelin gene in this region.ConclusionNeither the Leu72Met polymorphism nor the other intronic GHRL and GHSR SNPs were associated with T2DM, IR, or GHRL levels. Further investigations should be carried out to explain the molecular basis of the association of the GHRL peptide with T2DM and IR.

Abstract. Deletion polymorphisms for the glutathione S-transferase (GST) gene are associated with increased risk of cancer, and are implicated in detoxifying mutagenic electrophilic compounds. GST Polymorphic variants were reported for different populations. The aim of this study was to investigate the frequencies of GSTM1 and GSTT1 null genotypes among Bahraini, Lebanese and Tunisian Arabs. GST genotyping was done by multiplex PCR-based methods. Study subjects comprised 167 Bahrainis, 141 Lebanese and 186 Tunisians unrelated healthy individuals. GSTM1 deletion homozygosity of 49.7%, 52.5% and 63.4% were recorded for Bahraini, Lebanese and Tunisians, respectively. Among Bahrainis, the prevalence of GSTT1 null homozygotes was 28.7%, while in higher rates were seen in Lebanese (37.6%) and Tunisians (37.1%). Our results indicate that there are no major differences in allelic distribution of GSTM1 and GSTT1 genes between the three Arab populations investigated except between Bahrainis and Tunisians regarding the allelic distribution of GSTM1 gene (P = 0.013). Combined analysis of both genes revealed that 14.4% of Bahrainis, 16.3% of Lebanese and 21.0% of Tunisians harbor the deleted genotype of both genes. This is the first study that addresses GST gene polymorphism in Bahraini and Lebanese Arabs, and will help genetic studies on the association of GSTM1 and GSTT1 polymorphisms with disease risks and drug effects in Arab populations.

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