Association of plasma ghrelin levels and ghrelin rs4684677 polymorphism with mild cognitive impairment in type 2 diabetic patients

Abstract

Background and aimsPeople with insulin resistance and type 2 diabetes mellitus (T2DM) are at increased risks of cognitive impairment. We aimed to investigate the association of plasma ghrelin levels and ghrelin rs4684677 polymorphism with mild cognitive impairment (MCI) in T2DM patients.ResultsIn addition to elevated glycosylated hemoglobin (HbA1c), fasting blood glucose (FBG) and homeostasis model assessment of insulin resistance (HOMA-IR), T2DM patients with MCI had decreased plasma ghrelin levels compared with their healthy-cognition subjects (all p < 0.05). Further logistic regression analysis showed that ghrelin level was one of independent factors for MCI in T2DM patients (p < 0.05). Moreover, partial correlation analysis demonstrated that ghrelin levels were positively associated with the scores of Montreal Cognitive Assessment (r = 0.196, p = 0.041) and Auditory Verbal Learning Test-delayed recall (r = 0.197, p = 0.040) after adjustment for HbA1c, FBG and HOMA-IR, wherein the latter represented episodic memory functions. No significant differences were found for the distributions of genotype and allele of ghrelin rs4684677 polymorphism between MCI and control group.Materials and methodsA total of 218 T2DM patients, with 112 patients who satisfied the MCI diagnostic criteria and 106 who exhibited healthy cognition, were enrolled in this study. Demographic characteristics, clinical variables and cognitive performances were extensively assessed. Plasma ghrelin levels and ghrelin rs4684677 polymorphism were also determined.ConclusionsOur results suggest that decreased ghrelin levels are associated with MCI, especially with episodic memory dysfunction in T2DM populations.

Free Triiodothyronine Levels are Related to Executive Function and Scene Memory in Type 2 Diabetes Mellitus Patients Without Diagnosed Thyroid Diseases

“…In our previous study, we found higher HbA1c level, in T2DM patients with MCI than these without MCI. 51 , 52 These factors may limit the accuracy of results as confounding factors for a cross-section study. So, in the later analysis, these factors were corrected.…”

Association Between Ghrelin Gene Polymorphism and Cerebral Infarction

“…The protein encoded by the ghrelin gene is the ligand for the growth hormone secretagogue receptor, which mainly regulates the concentration of growth hormone in the body and affects some of the body’s functions through affecting the release of growth hormone, such as regulating growth and development, affecting sugar, lipid and protein metabolism, and relaxing the cardiovascular system [ 16 , 17 ]. It has been proved that the ghrelin gene polymorphisms can affect the occurrence and susceptibility to a variety of diseases, such as polycystic ovary syndrome [ 18 ], chronic hepatitis C [ 19 ], and type 2 diabetes mellitus [ 20 ]. In cerebral infarction patients, the effects of ghrelin gene polymorphisms have not been studied yet.…”

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“…Ghrelin was also involved in the neuro-modulation, neuro-protection and memory and learning processes [110]. Reduced ghrelin levels were associated with MCI in type 2 diabetes (T2DM) populations [111] and with metabolic changes in AD patients [112]. However, a recent study found that ghrelin modulated encoding-related brain function without enhancing memory formation in humans [113].…”