Association of the APOA-5 Genetic Variant rs662799 with Metabolic Changes after an Intervention for 9 Months with a Low-Calorie Diet with a Mediterranean Profile

In cross-sectional studies, the genetic variant rs662799 of the APOA5 gene is associated with high serum triglyceride concentrations, and in some studies, the effect of short-term dietary interventions has been evaluated. The aim of the present investigation was to evaluate the role of this genetic variant in metabolic changes after the consumption of a low-calorie diet with a Mediterranean pattern for 9 months. A population of 269 Caucasian obese patients was recruited. Adiposity and biochemical parameters were measured at the beginning (basal level) and after 3 and 9 months of the dietary intervention. The rs662799 genotype was assessed with a dominant analysis (TT vs. CT + CC). The APOA5 variant distribution was: 88.1% (n = 237) (TT), 11.5% (n = 31) (TC) and 0.4% (n = 1) (CC). There were significant differences only in triglyceride levels at all times of the study between the genotype groups. After 3 and 9 months of dietary intervention, the following parameters improved in both genotype groups: adiposity parameters, systolic pressure, total cholesterol, LDL cholesterol, leptin, adiponectin and the leptin/adiponectin ratio. The intervention significantly decreased insulin levels, HOMA-IR and triglyceride levels in non-C allele carriers (Delta 9 months TT vs. TC + CC). i.e., insulin levels (delta: −3.8 + 0.3 UI/L vs. −1.2 + 0.2 UI/L; p = 0.02), HOMA-IR levels (delta: −1.2 + 0.2 units vs. −0.3 + 0.1 units; p = 0.02), triglyceride levels (delta: −19.3 + 4.2 mg/dL vs. −4.2 + 3.0 mg/dL; p = 0.02). In conclusion, non-C allele carriers of rs662799 of the APOA5 gene showed a decrease of triglyceride, insulin and HOMA-IR levels after consuming a low-calorie diet with a Mediterranean pattern; we did not observe this effect in C allele carriers, despite a significant weight loss.

APOA-5 Genetic Variant rs662799: Role in Lipid Changes and Insulin Resistance after a Mediterranean Diet in Caucasian Obese Subjects

Background and Aims

This APOA5-1131C allele is related with a higher serum triglyceride levels and perhaps a different metabolic response to a dietary intervention. The aim of the present investigation was to evaluate SNP rs662799 in the APOA5 gene and its associations with metabolic effects after a hypocaloric diet with Mediterranean pattern.

Methods

A population of 363 Caucasian obese patients was enrolled. Anthropometric parameters and serum parameters (lipid profile, insulin, homeostasis model assessment (HOMA-IR), glucose, C reactive protein, adiponectin, resistin, and leptin levels) were measured, at basal time and after 3 months. All patients were genotyped in the rs662799 polymorphism.

Results

The APOA5 variant distribution was as follows: 89.3% (n = 324) (TT) were homozygous for the T allele, 10.5% (n = 38) (TC) were heterozygous, and 0.2% (n = 1) (CC) were homozygous for the C allele. Triglyceride levels were higher in patients with the C allele. After dietary intervention, BMI, weight, fat mass, waist circumference, systolic blood pressure, adiponectin, leptin, and adiponectin/leptin ratio improved significantly in both genotype groups TT and TC+CC. After dietary intervention, insulin levels (delta: −3.6 ± 0.8 UI/L vs. −1.5 ± 0.6 UI/L; P = 0.03), HOMA-IR (delta: −1.5 ± 0.4 units vs. −0.3 ± 0.2 units; P = 0.02), and triglyceride levels (delta: −19.3 ± 4.2 mg/dL vs. −3.2 ± 3.1 mg/dL; P = 0.02) decreased in non-C allele carriers.

Conclusions

C allele carriers of rs662799 of the APOA5 gene did not show an improvement in triglyceride, insulin, and HOMA-IR levels after a significant weight loss due to a hypocaloric diet with a Mediterranean pattern.

Quantile-Dependent Expressivity and Gene-Lifestyle Interactions Involving High-Density Lipoprotein Cholesterol

BACKGROUND

The phenotypic expression of a high-density lipoprotein (HDL) genetic risk score has been shown to depend upon whether the phenotype (HDL-cholesterol) is high or low relative to its distribution in the population (quantile-dependent expressivity). This may be due to the effects of genetic mutations on HDL-metabolism being concentration dependent.

METHOD

The purpose of this article is to assess whether some previously reported HDL gene-lifestyle interactions could potentially be attributable to quantile-dependent expressivity.

SUMMARY

Seventy-three published examples of HDL gene-lifestyle interactions were interpreted from the perspective of quantile-dependent expressivity. These included interactive effects of diet, alcohol, physical activity, adiposity, and smoking with genetic variants associated with the ABCA1, ADH3, ANGPTL4, APOA1, APOA4, APOA5, APOC3, APOE, CETP, CLASP1, CYP7A1, GALNT2, LDLR, LHX1, LIPC, LIPG, LPL, MVK-MMAB, PLTP, PON1, PPARα, SIRT1, SNTA1,and UCP1genes. The selected examples showed larger genetic effect sizes for lifestyle conditions associated with higher vis-à-vis lower average HDL-cholesterol concentrations. This suggests these reported interactions could be the result of selecting subjects for conditions that differentiate high from low HDL-cholesterol (e.g., lean vs. overweight, active vs. sedentary, high-fat vs. high-carbohydrate diets, alcohol drinkers vs. abstainers, nonsmokers vs. smokers) producing larger versus smaller genetic effect sizes. Key Message: Quantile-dependent expressivity provides a potential explanation for some reported gene-lifestyle interactions for HDL-cholesterol. Although overall genetic heritability appears to be quantile specific, this may vary by genetic variant and environmental exposure.

Gene-environment interactions due to quantile-specific heritability of triglyceride and VLDL concentrations

"Quantile-dependent expressivity" is a dependence of genetic effects on whether the phenotype (e.g., triglycerides) is high or low relative to its distribution in the population. Quantile-specific offspring-parent regression slopes (β_OP) were estimated by quantile regression for 6227 offspring-parent pairs. Quantile-specific heritability (h²), estimated by 2β_OP/(1 + r_spouse), decreased 0.0047 ± 0.0007 (P = 2.9 × 10^-14) for each one-percent decrement in fasting triglyceride concentrations, i.e., h² ± SE were: 0.428 ± 0.059, 0.230 ± 0.030, 0.111 ± 0.015, 0.050 ± 0.016, and 0.033 ± 0.010 at the 90th, 75th, 50th, 25th, and 10th percentiles of the triglyceride distribution, respectively. Consistent with quantile-dependent expressivity, 11 drug studies report smaller genotype differences at lower (post-treatment) than higher (pre-treatment) triglyceride concentrations. This meant genotype-specific triglyceride changes could not move in parallel when triglycerides were decreased pharmacologically, so that subtracting pre-treatment from post-treatment triglyceride levels necessarily created a greater triglyceride decrease for the genotype with a higher pre-treatment value (purported precision-medicine genetic markers). In addition, sixty-five purported gene-environment interactions were found to be potentially attributable to triglyceride's quantile-dependent expressivity, including gene-adiposity (APOA5, APOB, APOE, GCKR, IRS-1, LPL, MTHFR, PCSK9, PNPLA3, PPARγ2), gene-exercise (APOA1, APOA2, LPL), gene-diet (APOA5, APOE, INSIG2, LPL, MYB, NXPH1, PER2, TNFA), gene-alcohol (ALDH2, APOA5, APOC3, CETP, LPL), gene-smoking (APOC3, CYBA, LPL, USF1), gene-pregnancy (LPL), and gene-insulin resistance interactions (APOE, LPL).

Effects of a 3-year dietary intervention on age-related changes in triglyceride and apolipoprotein A-V levels in patients with impaired fasting glucose or new-onset type 2 diabetes as a function of the APOA5 -1131 T > C polymorphism

Background

The purpose of this study was to estimate the effects of a 3-year dietary intervention on age-related changes in triglyceride and apolipoprotein (apo A-V) levels in patients with impaired fasting glucose (IFG) or new-onset type 2 diabetes as a function of the APOA5 -1131 T > C polymorphism.

Methods

We genotyped the APOA5 -1131 T > C polymorphism in 203 Korean individuals with IFG or new-onset type 2 diabetes for the TT (n = 91), TC (n = 98), and CC (n = 14) alleles. Plasma apo A-V and triglyceride levels were evaluated at baseline and after a 3-year dietary intervention.

Results

Our results showed that HDL, glucose, insulin, HOMA-IR index, free fatty acids, and apo A-V decreased and brachial-ankle pulse wave velocity (ba-PWV) and malondialdehyde (MDA) increased at the 3-year follow-up visit compared with baseline. Plasma apo A-V levels were reduced in subjects with the C allele (TC or CC) (P = 0.036) and triglyceride levels were reduced in subjects with the TT allele (P = 0.047). Subjects with the C allele showed lower post-treatment apo A-V and higher post-treatment fasting triglyceride levels than subjects with the TT allele. Changes in apo A-V and triglyceride levels were negatively correlated in subjects with the TT allele and positively correlated in subjects with the C allele.

Conclusions

This study showed that the dietary intervention prevented an age-related increase in triglyceride levels in individuals with IFG or new-onset type 2 diabetes who possess the TT allele, but not the CT or CC allele, of the APOA5 -1131 T > C polymorphism.

Consumption of whole grains and legumes modulates the genetic effect of the APOA5 -1131C variant on changes in triglyceride and apolipoprotein A-V concentrations in patients with impaired fasting glucose or newly diagnosed type 2 diabetes

Background

The apolipoprotein A5 gene (APOA5) -1131 T > C polymorphism is associated with mild hypertriglyceridemia in type 2 diabetic subjects, and interacts with dietary fat in the determination of triglyceride concentrations. We examined whether a substitution of whole grains and legumes for refined rice in a high carbohydrate diet (about 65% of energy derived from carbohydrate) may modify the effect of this variant on changes in apolipoprotein A-V (apoA-V) and triglyceride concentrations.

Methods

We genotyped the APOA5 -1131 T > C in individuals with impaired fasting glucose (IFG) or newly diagnosed type 2 diabetes, who were randomly assigned to either a group ingesting whole grain and legume meals daily or a control group for 12 weeks.

Results

After dietary intervention, we observed significant interactions between the APOA5 -1131 T > C polymorphism and carbohydrate sources (whole grains and legumes versus refined rice) in the determination of mean percent changes in triglyceride and apoA-V (P interactions <0.001 and =0.038, respectively). In the refined rice group (n = 93), the carriers of the risk C allele (n = 50) showed a greater increase in the mean percent changes of triglyceride and apoA-V than noncarriers after adjusting for HOMA-IR (P = 0.004 and 0.021, respectively). The whole grain and legume group (n = 92), however, showed a decrease in fasting glucose, HOMA-IR, and triglyceride, and an increase in apoA-V, irrespective of genotype.

Conclusions

The data showed that the magnitude of the genetic effect of the APOA5 -1131C variant on triglyceride and apoA-V levels was modulated when substituting consumption of whole grains and legumes for refined rice as a carbohydrate source in IFG or diabetic subjects.

Trial registration

ClinicalTrials.gov: NCT01784952.

The association between APOA5 haplotypes and plasma lipids is not modified by energy or fat intake: the Czech HAPIEE study

BACKGROUND AND AIMS

Several smaller studies reported interactions between dietary factors and apolipoprotein A5 (APOA5) gene polymorphisms in determination of plasma lipids. We tested interactions between APOA5 haplotypes and dietary intake in determination of plasma triglycerides (TG) and other lipids.

METHODS AND RESULTS

Participants (5487 males and females aged 45-69) were classified according to the number (0, 1, 2+) of minor APOA5 alleles (using T-1131 > C; rs662799 and Ser19 > Trp; rs3135506 polymorphisms) and into three groups of low (bottom 25%), medium (26th-75th percentile) and high (top 25%) of intake of total energy and total, saturated and polyunsaturated fats, assessed by food frequency questionnaire. The age-sex adjusted geometric means of plasma TG increased with the number of minor alleles, from 1.57 (standard error 0.01), to 1.79 (0.02) to 2.29 (0.10) mmol/L (p < 0.00001) but TG did not differ between groups with low, medium and high total energy intake (p = 0.251). TG concentrations were highest in subjects with the combination of 2+ minor alleles and the highest energy intake (mean 2.59 [0.19], compared with 1.62 [0.03] in subjects with lowest energy intake and no minor allele) but the interaction between energy intake and APOA5 haplotypes was not statistically significant (p = 0.186). Analogous analyses with total, saturated and polyunsaturated fat intake yielded similar nonsignificant results. Effects of APOA5 and dietary intakes on total and HDL cholesterol were weaker and no interactions were significant.

CONCLUSION

In this Slavic Caucasian population sample, we did not detect the hypothesized interaction between common SNPs within the APOA5 gene and diet in determination of blood lipids.

Abdominal fat interacts with PNPLA3 I148M, but not with the APOC3 variant in the pathogenesis of liver steatosis in chronic hepatitis C

The patatin-like phospholipase domain-containing 3 gene (PNPLA3) and the apolipoprotein C3 gene (APOC3) have been studied in relation to liver steatosis and liver disease outcome. The aim of this study was to evaluate the influence of PNPLA3 p.I148M and APOC3 rs2854116 and rs2854117 polymorphisms on the clinical and histological presentation of chronic hepatitis C in an Italian population and their relationship with viral and anthropometric parameters. Patients with hepatitis C (n = 166) entered the study receiving a clinical, histological, virological and biochemical evaluation. APOC3 (rs2854116 and rs2854117) and PNPLA3 (p.I148M) variants were genotyped. PNPLA3 polymorphisms were associated with liver steatosis, which was significantly higher in patients with p.148I/M (P = 0.034) and p.148M/M (P = 0.004) variants than those homozygous for the PNPLA3 wild type. Excluding patients with HCV genotype 3, the association with liver steatosis and PNPLA3 variants was more marked (p.148I/I genotype vs p.148I/M, P = 0.02, and vs p.148M/M, P = 0.005). The APOC3 polymorphism was not associated with any of the evaluated parameters. Among the interacting factors, BMI and waist circumference correlated with liver steatosis (P = 0.008 and 0.004, respectively). Relationship between waist circumference and liver steatosis was analysed for the different PNPLA3 genotypes. Homozygous 148M patients showed a stronger correlation between waist circumference and steatosis than those carrying the other genotypes (P = 0.0047). In our hepatitis C-infected population, the PNPLA3 polymorphism influenced the development of liver steatosis, but not fibrosis progression. APOC3 polymorphisms had no effect on the development of steatosis and no influence on the PNPLA3 polymorphism. The amount of abdominal fat can increase the association of PNPLA3 p.I148M with liver steatosis.

Effects of APOA5 -1131T>C (rs662799) on fasting plasma lipids and risk of metabolic syndrome: evidence from a case-control study in China and a meta-analysis

The apolipoprotein A5 (APOA5) gene −1131T>C (rs662799) has been suggested to be involved in the pathway of lipid homeostasis and the development of metabolic syndrome (MetS). However, the findings are not consistent. To systematically evaluate the associations between −1131T>C polymorphism and fasting lipid parameters and the risk of MetS, we conducted a case-control study in a Chinese population and a meta-analysis. The findings from 1840 Chinese participants indicated that the C allele carriers had significantly higher fasting total cholesterol (TC), triglycerides (TG) and lower HDL-cholesterol (HDL-C) than the TT homozygotes carriers. The −1131C allele was also found to be significantly associated with increased risk of MetS (OR  =  1.40, 95% confidence interval (CI)  =  1.15, 1.69) compared to the TT homozygotes. In the meta-analysis of 51,868 participants from 46 East Asian studies, 26 European studies and 19 studies of other ethnic groups, the −1131C allele was associated with higher fasting TC (weighted mean difference (WMD)  =  0.08 mmol/L, 95% CI  =  0.05, 0.10, P = 1.74×10⁻⁹), TG (WMD  =  0.30 mmol/L, 95% CI  =  0.26, 0.33, P =  1.87×10⁻⁵⁵), LDL-cholesterol (LDL-C) (WMD  =  0.04 mmol/L, 95% CI  =  0.02, 0.07, P = 0.002), and lower HDL-C (WMD  =  −0.05 mmol/L, 95% CI  =  −0.06,−0.04, P = 1.88×10⁻²¹), respectively. Based on 12 studies with 5,573 MetS cases and 8,290 controls from 5 East Asian studies, 5 European studies and 2 studies of other ethnic groups, the −1131C allele was associated with increased risk of MetS with an OR (95% CI)  =  1.33 (1.16, 1.53) in the overall population, 1.43 (1.29, 1.58) in East Asian and 1.30 (0.94, 1.78) in European populations. In conclusion, the −1131C allele may be associated with elevated levels of fasting TG, TC, LDL-C and decreased HDL-C, and increased risk of MetS, especially in East Asians.

APOA5 genotype modulates 2-y changes in lipid profile in response to weight-loss diet intervention: the Pounds Lost Trial

BACKGROUND

The apolipoprotein A5 gene (APOA5) is a major gene that regulates lipid metabolism and is modulated by dietary factors. A novel variant rs964184 in APOA5 was identified to be associated with lipids in genome-wide association studies.

OBJECTIVE

We examined whether this variant modified changes in lipid concentrations in response to a 2-y weight-loss diet intervention in a randomized trial.

DESIGN

The current analyses were secondary analyses of a data set from the Pounds Lost Trial. We genotyped APOA5 rs964184 in 734 overweight or obese adults who were randomly assigned to one of 4 diets that differed in percentages of energy derived from fat, protein, and carbohydrate for 2 y. We evaluated changes in fasting serum concentrations of total cholesterol (TC), LDL cholesterol, HDL cholesterol, and triglyceride from baseline to 2 y of follow-up.

RESULTS

After a 2-y dietary intervention, we showed significant interactions between the APOA5 rs964184 polymorphism and dietary fat intake (low compared with high) in the determination of changes in TC, LDL cholesterol, and HDL cholesterol (P-interaction = 0.007, 0.017, and 0.006, respectively). In the low-fat intake group (20% of energy derived from fat), carriers of the risk allele (G allele) exhibited greater reductions in TC and LDL cholesterol than did noncarriers (P = 0.036 and 0.039, respectively), whereas in the high-fat diet group (40% of energy derived from fat), participants with the G allele had a greater increase in HDL cholesterol than did participants without this allele (P = 0.038).

CONCLUSION

Our data showed better improvement in lipid profiles from long-term low-fat diet intake in the APOA5 rs964184 risk allele.