The Correlation Between Circulating Ghrelin and Insulin Resistance in Obesity: A Meta-Analysis

Abstract

Background: Ghrelin, a peptide mainly produced by stomach X-A cells. It plays a pivotal role in the regulation of food intake and energy metabolism, including glucose metabolism and insulin sensitivity. However, the correlation between circulating ghrelin levels and insulin resistance in obesity remained uncertain. This meta-analysis aimed to clarify the association between ghrelin and IR in obesity.Methods: A systematic literature search was performed using PubMed, EMBASE, Cochrane Library and Web of Science until April 18, 2018 with the keywords “ghrelin” and “insulin resistance.” Two independent reviewers selected studies and assessed data. Subgroup analyses were performed to search for sources of heterogeneity. Funnel plots and Egger's test were used to detect publication bias. A random-effects model was used to calculate the pooled effect size.Results: Ten studies with 546 participants were included in this meta-analysis. We found that ghrelin levels were negatively correlated with IR in obese individuals. (r = −0.31; 95% CI: −0.45 to −0.18). Subgroup analysis revealed that circulating ghrelin levels were significantly negatively correlated with IR in people with normal fasting blood glucose (FBG) (<6.9 mmol/dl) (r = −0.28; 95% CI: −0.47 to −0.09, I2 = 39.5%), while there was no relationship between circulating ghrelin levels and IR in the high FBG group (>6.9 mmol/dl) (r = −0.15; 95% CI: −0.33 to 0.03, I2 = 0.0%). Publication bias was insignificant (Egger's test: P = 0.425).Conclusion: In obesity, circulating ghrelin levels were significantly negative correlated with insulin resistance in individuals with normal fasting blood glucose.

The Association Between Salivary Ghrelin Levels with Anthropometric Measures in Underweight, Normal, Overweight and Obese Healthy Adult Males

“…This is evidenced in a meta-analysis by Zhang et al on the association between circulatory ghrelin and obesity-associated insulin resistance which concluded a negative correlation between ghrelin level and insulin resistance. 47 The current study limited the assessment of ghrelin levels to saliva based on the pieces of evidence available on its reliability. The generalisability of the study results are limited by the small study sample size, limited age range of subjects, the inclusion of only one race, and that all the participants were from the same location and were all males.…”

Acylated ghrelin protects against doxorubicin‐induced nephropathy by activating silent information regulator 1

“…This was done as described in more detail in our previous studies 43,53 . Protein samples of the total cell homogenates or the pre‐precipitated proteins from the nuclear extract (40 µg/well) were separated by sodium dodecyl sulphate (SDS)‐polyacrylamide gel electrophoresis (different ratios, 8%‐15%) and then transferred onto nitrocellulose paper.…”

Ghrelin gastric tissue expression in patients with morbid obesity and type 2 diabetes submitted to laparoscopic sleeve gastrectomy: immunohistochemical and biochemical study

“…T2DM is a metabolic disorder that associated with hypergylcaemia, impaired insulin production and insulin resistance (IR). The latter is a commonly recognised finding that exacerbates elevated serum glucose measurements in patients with both diabetes and obesity [3]. The combination of these morbid conditions often has a negative impact on the achievement of either a normal weight or normoglycaemia, despite longterm behavioural changes towards a healthier life style [4].…”

“…There are many studies in the literature describing the contribution of ghrelin on glucose homeostasis [6]. The hormone has been associated with insulin sensitivity, release and IR, particularly in patients with higher BMI [3]. AG and DAG have opposite metabolic effects; the former has a hyperglycaemic action, whereas the activity of DAG inhibits the glucose-releasing stimulatory effect of AG [7].…”