The interaction between apolipoprotein B insertion/deletion polymorphism and macronutrient intake on lipid profile and serum leptin and ghrelin levels in type 2 diabetes mellitus patients

Relationship between lipoprotein B and the severity of coronary microvascular dysfunction

OBJECTIVE

Contributing factors for the development of heart failure (HF) involve both apolipoprotein B (ApoB) and coronary microvascular dysfunction (CMD). Although ApoB has been linked to diverse cardiovascular risks, its association with CMD remains unclear.

METHODS

A total of 145 patients undergoing cardiac single-photon emission computed tomography (SPECT) scan was enrolled into this retrospective study. Based on ApoB serum level, all subjects were classified into three groups (Group 1-3). Myocardial flow reserve (MFR) was calculated using myocardial blood flow (MBF) tested in different contexts.

RESULTS

ApoB serum level was positively correlated to rest MBF but inversely associated with stress MBF and MFR. Following adjustment for covariates, a significant relationship was observed between increased ApoB and decreased MFR. The predictive value of ApoB was test by Receiver Operating Characteristic Curve (ROC) analysis, showing an area under curve (AUC) of 0.87.

CONCLUSION

The findings indicated that a higher level of ApoB correlated with the severity of CMD.

Dietary Total Antioxidant Capacity Can Modify the Effects of Apo-B Polymorphisms (Ins/Del and EcoRI) on Lipid Profiles and Atherogenic Indices Between Diabetic Patients

We aimed to study the role of Apolipoprotein B (Apo-B) polymorphisms (Ins/Del and EcoRI) and genotype interaction on lipid profiles and atherogenic indices in response to changes in dietary total antioxidant capacity (DTAC) of diet. This cross-sectional study consisted of 700 diabetic patients. Biochemical markers including total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), superoxide dismutase (SOD), C-reactive protein (CRP), total antioxidant capacity (TAC), interlukin-18 (IL-18), and Prostaglandin F2α (PGF2α) were measured based on standard protocols. Genotyping of the Apo-B polymorphisms was conducted by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Subjects with Ins/Ins genotype with higher DTAC intake had lower TG, AIP, and AC compared to Del-allele carriers. Moreover, A-allele carriers (EcoRI) with a higher median intake of DTAC had lower body mass index (BMI) and waist circumference (WC) compared to GG homozygotes. For combined genotypes, the EcoRI only variant (Ins/Ins and AA + AG) with higher DTAC intake had lower BMI and WC. Moreover, Ins/Del only variant (Ins/del + del/del and GG) with more adherence to DTAC had higher TG and AIP. Our study showed that Apo-B polymorphisms interact with the antioxidant capacity of diet to ameliorate the risk of cardio-metabolic diseases, especially atherosclerosis in the A carriers of EcoR1 and Ins/Ins homozygous of Ins/Del polymorphism.

Dietary acid load adopts the effect of ApoB ins/del genetic variant (rs11279109) on obesity trait, cardiovascular markers, lipid profile, and serum leptin level among patients with diabetes: a cross-sectional study

ApoB insertion/deletion (ins/del) genetic variant (rs11279109) is thought to be related to cardio-metabolic markers and obesity. This association has the potential to be modified by dietary patterns. Since the majority of studies concerned the role of dietary acid load (DAL) or ApoB in type 2 diabetes mellitus (T2DM) and its complications independently, and due to the insufficient data regarding the possible interactions between ApoB genetic variants and DAL on anthropometric and metabolic markers, we aimed to study the interaction between this genetic variant and dietary acid load (DAL) on cardio-metabolic markers, along with leptin among Iranian individuals with T2DM. 700 T2DM patients were randomly recruited. A validated semi-quantitative food frequency questionnaire was used for DAL calculation including potential renal acid load (PRAL) and net-endogenous acid production (NEAP). The polymerase chain reaction was used for genotyping the ApoB ins/del (rs11279109). The general linear model was applied to find the interactions in the crude and adjusted models. Patients with del/del genotype (rs11279109) with high PRAL intake have lower low-density lipoprotein cholesterol (LDL-C) (Pinteraction = 0.004), LDL/HDL ratio (Pinteraction = 0.02), total cholesterol (TC) (Pinteraction = 0.04), triglyceride (TG) (Pinteraction = 0.04), leptin (Pinteraction = 0.04) and interleukin-18 (IL-18) (Pinteraction = 0.04). Moreover, the interaction of gene and DAL in the PRAL method on TG concentration (P = 0.04), waist circumference (WC) (P = 0.04), and LDL/HDL ratio (P = 0.04) were significant. Eventually, a positive relationship was observed between the presence of the del/del genotype (rs11279109) and higher levels of TG, TC, LDL-C, IL-18, and LDL/HDL, in individuals with lower adherence to DAL, after adjusting for various covariates. Further studies are needed to investigate and confirm these findings.

Genotype-based precision nutrition strategies for the prediction and clinical management of type 2 diabetes mellitus

Globally, type 2 diabetes mellitus (T2DM) is one of the most common metabolic disorders. T2DM physiopathology is influenced by complex interrelationships between genetic, metabolic and lifestyle factors (including diet), which differ between populations and geographic regions. In fact, excessive consumptions of high fat/high sugar foods generally increase the risk of developing T2DM, whereas habitual intakes of plant-based healthy diets usually exert a protective effect. Moreover, genomic studies have allowed the characterization of sequence DNA variants across the human genome, some of which may affect gene expression and protein functions relevant for glucose homeostasis. This comprehensive literature review covers the impact of gene-diet interactions on T2DM susceptibility and disease progression, some of which have demonstrated a value as biomarkers of personal responses to certain nutritional interventions. Also, novel genotype-based dietary strategies have been developed for improving T2DM control in comparison to general lifestyle recommendations. Furthermore, progresses in other omics areas (epigenomics, metagenomics, proteomics, and metabolomics) are improving current understanding of genetic insights in T2DM clinical outcomes. Although more investigation is still needed, the analysis of the genetic make-up may help to decipher new paradigms in the pathophysiology of T2DM as well as offer further opportunities to personalize the screening, prevention, diagnosis, management, and prognosis of T2DM through precision nutrition.

Interactions of BDNF Val66met and dietary indices in relation to metabolic markers among patient with type 2 diabetes mellitus: a cross-sectional study

BACKGROUND

Gene-diet interaction is related to the progression of diabetes and cardiovascular diseases biomarkers. We aimed to evaluate the interaction between diet quality indices and BDNF Val66Mat (rs6265) on cardiometabolic markers among diabetic patients.

METHODS

This cross-sectional study was conducted on 634 patients with type 2 diabetes mellitus, which were randomly recruited from diabetic centers in Tehran. Dietary intakes were estimated by a previously validated semi-quantitative food frequency questionnaire comprising 147 items. All participants were categorized into three categories, based on healthy eating index (HEI), diet quality index (DQI), and phytochemical index (PI) scores. Polymerase chain reaction was used for genotyping the BDNF Val66Met. Interactions were tested using analysis of covariance in adjusted and crude models.

RESULTS

Our result showed that higher DQI, HEI, and PI scores significantly decrease body mass index and waist circumference among individuals with Met/Met, Val/Met, and Val/Val genotypes (P interactions < 0.05). Moreover, the highest quartile of the DQI and PI, compared to the lowest, showed lower TG level among Met allele carriers compared to Val/Val homozygotes (P interaction = 0.004 and 0.01, respectively) and a faster reduction in IL-18 and TC level was seen among Met/Met, Val/Met who had higher HEI intake than those with Val/Val genotype.

CONCLUSIONS

BDNF Val66Met polymorphism may interact with HEI, DQI, and PI. We have revealed that Met allele acts as a protective allele for diabetic patients and may have a beneficial influence on cardio-metabolic factors through regulating dietary intake.

Interactions of dietary insulin index and dietary insulin load with brain-derived neurotrophic factor (BDNF) Val66Met polymorphism in relation to cardiometabolic markers in Iranian diabetic patients: a cross-sectional study

The progression of cardiometabolic diseases is determined by both genetic and environmental factors. Gene-diet interactions may therefore be important in modulating the risks of developing metabolic diseases. The objectives were to investigate the effect of the interaction between brain-derived neurotrophic factor (BDNF) Val66Met polymorphisms and dietary insulin index (DII) and dietary insulin load (DIL) on cardiometabolic markers among diabetic patients. In this cross-sectional study, blood samples were collected from 667 patients. DIL and DII were defined using a validated FFQ. Genotyping the BDNF Val66Met polymorphism was conducted by the PCR-Restriction fragment length polymorphism (RFLP) method. Interactions between dietary indices and gene variants were evaluated using a generalised linear model. PGF2a concentrations were significantly higher among Val homozygotes than Met-allele carrier. This study revealed that, compared with individuals with the Val/Val genotype, those with the Met/Val or Met/Met genotype had lower BMI (P_interaction = 0·04), TAG (P_interaction = 0·04), leptin (P_interaction = 0·01), LDL (P_interaction = 0·04) and total cholesterol (P_interaction = 0·01) when they consumed diets higher on the DIL index. Moreover, the highest quartile of the DIL, compared with the lowest, showed increase in waist circumference (P_interaction = 0·02) and LDL/HDL (P_interaction = 0·04) for Val/Val homozygotes compared with Met-allele carriers. BDNF Val66Met variants may interact with DIL and DII, thus be involved in the development of cardiometabolic risk factors. If diabetic patients with Met alleles regulate dietary intakes, they have a protective opportunity to regulate their cardiometabolic markers.

Macronutrient intake modulates impact of EcoRI polymorphism of ApoB gene on lipid profile and inflammatory markers in patients with type 2 diabetes

We sought to examine whether dietary intakes may affect the relationship between ApoB EcoRI and lipid profile, as well as serum inflammatory markers, in patients with type 2 diabetes (T2DM). This current study consisted of 648 diabetic patients. Dietary intake was calculated by a food frequency questionnaire. Biochemical markers (high-density lipoprotein (HDL), total cholesterol (TC), LDL, TG, CRP, IL-18, PGF2α) were measured based on standard protocols. Genotyping of the Apo-B polymorphisms (rs1042031) was conducted by the PCR–RFLP method. The gene-diet interactions were evaluated using GLMs. In comparison to GG homozygotes, A-allele carriers with above the median -CHO intake (≥ 54 percent of total energy) had considerably greater TC and PGF2a concentrations. Furthermore, as compared to GG homozygotes, A-allele carriers with above the median protein intake (≥ 14 percent of total energy) had higher serum levels of TG (P = 0.001), CRP (P = 0.02), TG/HDL (P = 0.005), and LDL/HDL (P = 0.04) ratios. Moreover, A-allele carriers with above the median total fat intake (≥ 35 percent of total calories) had significantly higher TC level (P = 0.04) and LDL/HDL (P = 0.04) ratios compared to GG homozygotes. Furthermore, when compared to GG homozygotes, A-allele carriers who consumed above the median cholesterol (> 196 mg) had greater TG (P = 0.04), TG/HDL (P = 0.01) ratio, and IL-18 (P = 0.02). Furthermore, diabetic patients with the GA, AA genotype who consume above the median cholesterol had lower ghrelin levels (P = 0.01). In terms of LDL/HDL ratio, ApoB EcoRI and dietary intakes of specific fatty acids (≥ 9 percent for SFA and ≥ 12 percent for MUFA) had significant interaction. LDL/HDL ratio is greater in A-allele carriers with above the median SFA intake (P = 0.04), also when they consumed above the median MUFA this association was inverse (P = 0.04). Our study showed that plasma lipid levels in participants carrying the (AA or AG) genotype were found to be more responsive to increasing the percentage of energy derived from dietary fat, CHO, protein, SFA, and cholesterol consumption. Therefore, patients with a higher genetic susceptibility (AA or AG) seemed to have greater metabolic markers with a higher percentage of macronutrient consumption. Also, ApoB EcoRI correlations with metabolic markers might be attenuated with above the median MUFA consumption.

Association between sleep duration and incidence of type 2 diabetes in China: the REACTION study

Backgrounds:

Inadequate sleep duration is associated with a higher risk of type 2 diabetes and the relationship is nonlinear. We aim to assess the curve relationship between night sleep duration and the incidence of type 2 diabetes in China.

Methods:

A cohort of 11,539 participants from the REACTION study without diabetes at baseline (2011) were followed until 2014 for the development of type 2 diabetes. The average number of hours of sleep per night was grouped. Incidence rates and odds ratios (ORs) were calculated for the development of diabetes in each sleep duration category.

Results:

Compared to people who sleep for 7 to 8 h/night, people with longer sleep duration (≥9 h/night) had a greater risk of type 2 diabetes (OR: 1.27; 95% CI: 1.01–1.61), while shorter sleep (<6 h/night) had no significant difference in risk of type 2 diabetes. When the dataset was stratified based on selected covariates, the association between type 2 diabetes and long sleep duration became more evident among individuals <65 years of age, male, body mass index <24 kg/m² or with hypertension or hyperlipidemia, no interaction effects were observed. Furthermore, compared to people persistently sleeping 7 to 9 h/night, those who persistently slept ≥9 h/night had a higher risk of type 2 diabetes. The optimal sleep duration was 6.3 to 7.5 h/night.

Conclusions:

Short or long sleep duration was associated with a higher risk of type 2 diabetes. Persistently long sleep duration increased the risk.

Serum Ghrelin Concentration in Patients With Primary Biliary Cirrhosis (PBC)

INTRODUCTION

The appetite-modulating hormone ghrelin may have a role in the etiology of anorexia which is a serious concern in patients with primary biliary cirrhosis (PBC). This study aims to assess the difference in ghrelin level between cases of PBC and healthy controls matched for age and gender, and to evaluate the level of ghrelin in relation to clinical and laboratory findings among cases.

METHODS

Twenty patients with primary biliary cirrhosis and 30 healthy controls matched by gender and age were recruited. The severity of liver disease was determined using the Child-Pugh grading system. Clinical comorbidities such as a history of ascites, gastrointestinal bleeding, and encephalopathy were evaluated. A commercial enzyme-linked immunosorbent assay was used to measure total ghrelin.  Results: PBC cases had a significantly higher average level of ghrelin (2305.3 ± 639.4) pg/mL compared to controls (682 ± 197.3) pg/mL. Furthermore, the minimum reported level in cases was 1258 pg/mL compared to 326 pg/mL in controls, while the maximum level nearly tripled the control's maximum level. In PBC patients, plasma levels of total ghrelin showed a weak positive correlation with age, an inverse correlation with body mass index, and were not associated with gender. The level was significantly higher than those in the controls. Ghrelin was associated with the severity of cirrhosis. Levels of serum ghrelin were higher in patients with associated comorbidities such as a history of ascites, gastrointestinal bleeding, and encephalopathy.

CONCLUSIONS

Our study demonstrated elevated serum ghrelin levels in patients with primary biliary cirrhosis. Serum ghrelin was associated with the degree of severity and the presence of related comorbidities. Patients with primary biliary cirrhosis remain anorexic and catabolic despite elevated ghrelin levels, suggesting tissue resistance to this anabolic peptide which could be crucial to understanding anorexia and cachexia in primary biliary cirrhosis.

Dietary quality indices modify the effects of apolipoprotein B polymorphisms on biochemical and anthropometric factors in type 2 diabetes mellitus

We tried to identify the interaction between dietary quality indices and apolipoprotein B Ins/Del and EcoR1 polymorphisms on biochemical and anthropometric factors in patients with type 2 diabetes mellitus (T2DM). This cross-sectional study recruited 700 adults with T2DM in Tehran. The genotypes of Ins/Del and EcoR1 single nucleotide polymorphisms (SNP) were explored via polymerase chain reaction (PCR). Dietary quality index-international (DQI-I), healthy eating index-2015 (HEI-2015) and dietary phytochemical index (DPI) were calculated by semi-quantitative food frequency questionnaire (FFQ). In both crude and adjusted model for confounding factors, we observed significant interactions between DQI-I and Ins/Del SNP on leptin in and 8-iso-prostaglandin F2 α (8-iso-PGF2α), DPI and EcoR1 SNP on total cholesterol (TC) and between Ins/Del SNP and HEI-2015 on interleukin-18 (IL-18). Furthermore, in crude model there were close to meaningful interactions between EcoR1 SNP and DQI-I on total antioxidant capacity (TAC) and between EcoR1 SNP and HEI-2015 on serum leptin and superoxide dismutase (SOD) levels. Our finding indicated that the association between DQI-I, HEI-2015 and DPI with IL-18, TC, leptin and 8-iso-PGF2α in patients with T2DM might be dependent on Ins/Del and EcoR1 variants in ApoB gene.

Interaction between dietary total antioxidant capacity and BDNF Val66Met polymorphism on lipid profiles and atherogenic indices among diabetic patients

Brain-derived neurotrophic factor (BDNF) belongs to the "neurotrophin" family of growth factors, and it has recently been associated to cardiovascular disease (CVD). We anticipated that BDNF Val66Met polymorphisms may alter CVD risk markers such as serum lipid profile differences, and interaction with total antioxidant capacity of diet (DTAC) could alter these clinical parameters. This cross-sectional study consisted of 667 diabetic patients (39.7% male and 60.3% female). DTAC was calculated by international databases. Biochemical markers including total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), superoxide dismutase (SOD), C-reactive protein (CRP), total antioxidant capacity (TAC), pentraxin-3 (PTX3), isoprostaneF2α (PGF2α). interleukin 18 (IL18), leptin and ghrelin were measured by standard protocol. Atherogenic indices (AIP, AC, CR-I, CR-II) were calculated. Genotyping of the BDNF Val66Met polymorphisms was conducted by the real-time PCR-RFLP method. The gene-diet interactions were evaluated using a generalized linear mode (GLMs). Carriers of the Val/Met genotype who were in the higher median intake of FRAP had lower HDL (P:0.04) and higher TG (P:0.005), AIP (P:0.02) and AC (P:0.02) index compared to Val/Val genotypes with lower median intake. Moreover, diabetic patients with Val/Met genotype who consumed higher ORAC intake had increased odds for anthropometric indices (BMI (P:0.01) and WC (P:0.03)), lipid profiles (TG) (P:0.01), and atherogenic index (AIP) (P:0.02), also decreased odds for HDL (P:0.03) concentration compared to reference group whit lower ORAC intake. Individuals with Val/Met genotype who consumed higher TRAP intake had increased odds for WC (P:0.04), TC (P:0.001), TG (P < 0.001), AIP (P < 0.001) and AC (P < 0.001). Finally, Val/Met patients with a higher median intake of TEAC had higher TG (P:0.02), AIP (P:0.009) and AC (P:0.03) compared to the reference group whit lower TEAC intake. Our study showed that Val/Met genotype had also the highest lipid profile and atherogenic indices even in the highest adherence to DTAC. While it seems that the presence of the Val/Val wild-type and BDNF Met/Met homozygotes in diabetic patients with a high DTAC is a protective factor.

Interaction between the dietary indices and PPAR-γ Pro12Ala gene variants on cardiovascular risk factors in patients with type 2 diabetes mellitus

AIMS

We investigated the interaction between peroxisome proliferator-activated receptor gamma (PPAR-γ) Pro12Ala polymorphism and healthy eating index (HEI), Dietary Quality Index-International (DQI-I), and dietary phytochemical index (DPI) on cardiovascular disease (CVD) risk factors in patients with type 2 diabetes mellitus (T2DM).

METHODS

This cross-sectional study was conducted on 393 diabetic patients. PPAR-γ Pro12Ala was genotyped by the PCR-RFLP method. Biochemical markers including total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), superoxide dismutase (SOD), C-reactive protein (CRP), total antioxidant capacity (TAC), pentraxin-3 (PTX3), isoprostaneF2α (PGF2α). Interleukin 18 (IL18), leptin, and ghrelin were measured by standard protocol. Food-frequency questionnaires (FFQ) were used for dietary indices (DQI-I, DPI, HEI) calculation.

RESULTS

Homozygous carriers of the rs1801282 C allele showed higher leptin compared G allele carriers (P = .015). The rs1801282-DQI-I interactions were significant on waist circumference (WC) (P = .019). Thus, C-allele carriers in the higher tertile of DQI-I had higher WC compared with GG homozygous. Further, an interaction was observed between PPAR rs1801282 polymorphism and DQI-I on serum IL-18 level (P = .032). Besides, a significant rs1801282-DPI interaction was shown on HDL concentration (P = .041), G allele carriers who were in the highest tertile of DPI, had lower HDL. Moreover, there were significant rs1801282-HEI interactions on serum leptin (P = .021). Individuals with (CC, CG) genotypes in the higher tertile of HEI, had lower leptin concentration.

CONCLUSION

Higher dietary indices (DQI-I, DPI, HEI) may affect the relationship between PPAR-γ Pro12Ala polymorphism and WC, ghrelin, leptin, HDL, and IL-18 concentration in patients with T2DM.

Quantile-specific heritability of sibling leptin concentrations and its implications for gene-environment interactions

"Quantile-dependent expressivity" occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g., leptin) is high or low relative to its distribution. Leptin concentrations are strongly related to adiposity, whose heritability is quantile dependent. Whether inheritance of leptin concentrations is quantile dependent, and whether this explains the greater heritability in women than men in accordance with their greater adiposity, and explains other gene-environment interactions, remains to be determined. Therefore, leptin and leptin receptor concentrations from 3068 siblings in 1133 sibships from the Framingham Heart Study Third Generation Cohort were analyzed. Free leptin index (FLI) was calculated as the ratio of leptin to soluble leptin receptor concentrations. Full-sib (β_FS) regression slopes were robustly estimated by quantile regression with nonparametric significance assigned from 1000 bootstrap samples. The analyses showed β_FS increased significantly with increasing percentiles of the offspring's age- and sex-adjusted leptin distribution (P_linear = 0.0001), which was accelerated at the higher concentrations (P_quadratic = 0.0003). β_FS at the 90th percentile (0.418 ± 0.066) was 4.7-fold greater than at the 10th percentile (0.089 ± 0.032, P_difference = 3.6 × 10^-6). Consistent with quantile-dependent expressivity, the β_FS was greater in female sibs, which was attributable to their higher leptin concentrations. Reported gene-environment interactions involving adiposity and LEP, LEPR, MnSOD, PPARγ, PPARγ2, and IRS-1 polymorphisms were consistent with quantile-dependent expressivity of leptin concentrations. β_FS for leptin receptor concentrations and free leptin index also increased significantly with increasing percentiles of their distributions (P_linear = 0.04 and P_linear = 8.5 × 10^-6, respectively). In conclusion, inherited genetic and shared environmental effects on leptin concentrations were quantile dependent, which likely explains male-female differences in heritability and some gene-environment interactions.

Interactive associations of the INAFM2 rs67839313 variant and egg consumption with type 2 diabetes mellitus and fasting blood glucose in a Chinese population: A family-based study

BACKGROUND

INAFM2 rs67839313 was associated with type 2 diabetes (T2DM) in Japanese populations but not in other populations. We aimed to validate the association of rs67839313 with T2DM and explore interactive associations of INAFM2 rs67839313 and egg consumption with T2DM and fasting blood glucose (FBG) in a Chinese population.

METHODS

In total, 7175 participants (4202 T2DM cases) from 3980 families were included and categorized into two groups (<4 and ≥4 eggs/week) according to the median egg consumption. Multilevel logistic regression and linear regression models were performed to estimate the genetic associations of rs67839313 with T2DM and FBG, respectively. The crossproduct term between the variant and egg was included in the models for interaction analysis.

RESULTS

We found that rs67839313_T was associated with an increased risk of T2DM (1.22 [95% CI: 1.17-1.27], P < 0.001). Among individuals with the rs67839313_T genotype, those with egg consumption <4/week (1.37 [1.25-1.51]) had a higher T2DM risk than those with egg consumption ≥4/week (1.17 [1.11-1.23]). A significant interactive effect between rs67839313_T and egg consumption on T2DM risk was identified (P = 0.008). Moreover, among participants without T2DM, rs67839313_T was associated with FBG, with a 0.188 mmol/l increase and a 0.152 mmol/l decrease among those consuming <4 eggs/week and ≥4 eggs/week, respectively. The interaction between rs67839313_T and egg consumption was observed to be significantly associated with FBG (P = 0.003).

CONCLUSIONS

INAFM2 rs67839313_T was associated with increased T2DM risk and FBG levels in Chinese individuals, and consuming more eggs may eliminate the associated genetic risk. This finding has important implications for understanding the genetic pathogenesis of T2DM and for the precision nutrition management of T2DM.

Ghrelin, a gastrointestinal hormone, regulates energy balance and lipid metabolism

Ghrelin, an acylated peptide hormone of 28 amino acids, is an endogenous ligand of the released growth hormone secretagogue receptor (GHSR). Ghrelin has been isolated from human and rat stomach and is also detected in the hypothalamic arcuate nucleus. Ghrelin receptor is primarily located in the neuropeptide Y and agouti-related protein neurons. Many previous studies have shown that ghrelin and GHSR are involved in the regulation of energy homeostasis, and its administration can increase food intake and body weight gain. AMP-activated protein kinase is activated by ghrelin in the hypothalamus, which contributes to lower intracellular long-chain fatty acid level. Ghrelin appears to modulate the response to food cues via a neural network involved in the regulation of feeding and in the appetitive response to food cues. It also increases the response of brain areas involved in visual processing, attention, and memory to food pictures. Ghrelin is also an important factor linking the central nervous system with peripheral tissues that regulate lipid metabolism. It promotes adiposity by the activation of hypothalamic orexigenic neurons and stimulates the expression of fat storage-related proteins in adipocytes. Meanwhile, ghrelin exerts direct peripheral effects on lipid metabolism, including increase in white adipose tissue mass, stimulation of lipogenesis in the liver, and taste sensitivity modulation.