Genetic variants of apolipoprotein B: relation to serum lipid levels and coronary artery disease among the Finns

Haplotype analysis and linkage disequilibrium of ApoB gene polymorphisms and its relationship with hyperlipidemia in patients with acne vulgaris

BACKGROUND

Acne vulgaris (AV) is a chronic, multifactorial inflammatory disease of the pilosebaceous unit brought on by hormonal imbalance, excessive sebum production, follicular hyperkeratinization, inflammation and Cutibacterium acne. Acne patients are characterized by alteration of the lipid profile. Apolipoprotein B gene (ApoB) plays an essential role in lipoprotein biosynthesis and multiple single-nucleotide polymorphisms (SNPs) in ApoB are associated with dyslipidemia.

AIM

The aim of this study was to estimate the alteration of lipid profiles in AV, determine the genetic association with lipid profile alteration by studying the ApoB gene polymorphisms, and to identify the exact haplotypes associated with acne and lipid profile alteration.

SUBJECTS AND METHODS

In a case-control study consisting of 63 non-obese acne patients and 43 healthy controls, all participants underwent biochemical, anthropological assessments, and genetic analysis for ApoB polymorphisms.

RESULT

Our results indicate that serum ApoB and the lipid profile were higher in acne patients compared with healthy subject. The most common haplotypes in acne patients were rs562338 A/rs17240441 I/c.12669 A/rs1042034 G, whereas the most common haplotypes in healthy subjects were rs562338 G/rs17240441 D/c.12669 A/rs1042034 G. Patients with mild acne had higher serum ApoB levels p = 0.005. Also, the low-density lipoprotein cholesterol (LDL-C) level was higher in mild acne compared with other acne groups, with a highly significant variation of p ≤ 0.001.

CONCLUSION

We found a significant variation between the acne group and healthy controls in serum ApoB, triglycerides, total cholesterol and LDL-C. The most common haplotypes in acne patients are rs562338 A/, rs17240441 I/, c.12669 A/ and rs1042034 G, and there is a linkage disequilibrium between the four selected SNPs.

Insights from human congenital disorders of intestinal lipid metabolism

The intestine must challenge the profuse daily flux of dietary fat that serves as a vital source of energy and as an essential component of cell membranes. The fat absorption process takes place in a series of orderly and interrelated steps, including the uptake and translocation of lipolytic products from the brush border membrane to the endoplasmic reticulum, lipid esterification, Apo synthesis, and ultimately the packaging of lipid and Apo components into chylomicrons (CMs). Deciphering inherited disorders of intracellular CM elaboration afforded new insight into the key functions of crucial intracellular proteins, such as Apo B, microsomal TG transfer protein, and Sar1b GTPase, the defects of which lead to hypobetalipoproteinemia, abetalipoproteinemia, and CM retention disease, respectively. These "experiments of nature" are characterized by fat malabsorption, steatorrhea, failure to thrive, low plasma levels of TGs and cholesterol, and deficiency of liposoluble vitamins and essential FAs. After summarizing and discussing the functions and regulation of these proteins for reader's comprehension, the current review focuses on their specific roles in malabsorptions and dyslipidemia-related intestinal fat hyperabsorption while dissecting the spectrum of clinical manifestations and managements. The influence of newly discovered proteins (proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 protein) on fat absorption has also been provided. Finally, it is stressed how the overexpression or polymorphism status of the critical intracellular proteins promotes dyslipidemia and cardiometabolic disorders.

Apolipoprotein Gene Polymorphisms (APOB, APOC111, APOE) in the Development of Coronary Heart Disease in Ethnic Groups of Kazakhstan

BACKGROUND

Previous Analysis of polymorphism of genes associated with the development of coronary heart disease (CHD) reveals that the frequency distribution of genotypes and alleles depends on the ethnic characteristics of the populations under study. Further impetus is derived from the well -established links between alcoholism (high prevalence in Kazakhstan region) and cardiovascular disorders.

OBJECTIVES

The purpose of this study was to examine a number of apolipoprotein gene polymorphisms and correlate these alleles with changes of lipid profile in CHD patients of Kazakh and Uyghur nationalities.

METHODS

Four-Hundred Forty Eight (448) males of Kazakh and Uyghur nationalities residing in Kazakhstan were evaluated and genotyped. The age range of these subjects was 30-55 years which included both afflicted and controls. Specifically, 161- Kazakhs suffered from myocardial infarction compared to 112 health controls; 80- Uyghurs suffered from CHD compared to 95 health controls. Blood lipid profiles were examined in the total cohort. Genotyping was performed by polymerase chain reaction (PCR) using oligonucleotide primers identifying; ApoB; ApoC111; and APOE gene polymorphisms.

RESULTS

Initial screening revealed a significant inter-ethnic difference on the frequency of alleles associated with both the ApoB and APOE genes. We found that the X1 ApoB gene polymorphism is overrepresented in healthy Kazakhs relative to Uyghurs [86.4% in Kazakhs vs. 69.4% in Uyghurs]. Moreover, we found that the E4APOE allele was also overrepresented in healthy Kazakhs relative to Uyghurs [16.8% in Kazakhs vs. 9.5% in Uyghurs]. There was a significant relationship of polymorphisms of APOE such as ApoB and ApoC 111 with the value of lipid indices in Kazakhs. Additionally, we found that the E4 allele of the APOE gene also correlated with the value of lipid indices in Kazakhs. Further evaluation showed that the X2 allele of the ApoB and the S2 allele of the ApoCIII gene significantly associated with the lipid indices of Uyghurs.

CONCLUSION

This systematic investigation confirms the association of various alleles of Apolipoprotein gene polymorphisms and contribution to aberrant lipid metabolism. Putatively at least in our population we are proposing that certain gene polymorphisms of Apolipoprotein genes such as ApoB; ApoC111; APOE ; X2 of ApoB; and S2 of ApoCIII differentially represented in either Kazakhs or Uyghurs are genetic markers of hypertriglyceridemia.

Effect of the 3'APOB-VNTR polymorphism on the lipid profiles in the Guangxi Hei Yi Zhuang and Han populations

BACKGROUND

Apolipoprotein (Apo) B is the major component of low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) and chylomicrons. Many genetic polymorphisms of the Apo B have been described, associated with variation of lipid levels. However, very few studies have evaluated the effect of the variable number of tandem repeats region 3' of the Apo B gene (3'APOB-VNTR) polymorphism on the lipid profiles in the special minority subgroups in China. Thus, the present study was undertaken to study the effect of the 3'APOB-VNTR polymorphism on the serum lipid levels in the Guangxi Hei Yi Zhuang and Han populations.

METHODS

A total of 548 people of Hei Yi Zhuang were surveyed by a stratified randomized cluster sampling. The epidemiological survey was performed using internationally standardized methods. Serum lipid and apolipoprotein levels were measured. The 3'APOB-VNTR alleles were determined by polymerase chain reaction (PCR) followed by electrophoresis in polyacrylamide gels, and classified according to the number of repeats of a 15-bp hypervariable elements (HVE). The sequence of the most common allele was determined using the PCR and direct sequencing. The possible association between alleles of the 3'APOB-VNTR and lipid variables was examined. The results were compared with those in 496 people of Han who also live in that district.

RESULTS

Nineteen alleles ranging from 24 to 64 repeats were detected in both Hei Yi Zhuang and Han. HVE56 and HVE58 were not be detected in Hei Yi Zhuang whereas HVE48 and HVE62 were totally absent in Han. The frequencies of HVE26, HVE30, HVE46, heterozygote, and short alleles (< 38 repeats) were higher in Hei Yi Zhuang than in Han. But the frequencies of HVE34, HVE38, HVE40, homozygote, and long alleles (> or = 38 repeats) were lower in Hei Yi Zhuang than in Han (P < 0.05-0.01). The levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and Apo B in Hei Yi Zhuang but not in Han were higher in VNTR-LS (carrier of one long and one short alleles) than in VNTR-LL (the individual carrying two long alleles) genotypes. The levels of TC, triglycerides (TG), LDL cholesterol, and Apo B in Hei Yi Zhuang were higher in both HVE34 and HVE36 alleles than in HVE32 allele. The levels of TC, TG, HDL-C and Apo B in Hei Yi Zhuang were also higher in homozygotes than in heterozygotes. There were no significant differences in the detected lipid parameters between the VNTR-SS (carrier of two short alleles) and VNTR-LS or VNTR-LL genotypes in both ethnic groups.

CONCLUSION

There were significant differences of the 3'APOB-VNTR polymorphism between the Hei Yi Zhuang and Han populations. An association between the 3'APOB-VNTR polymorphism and serum lipid levels was observed in the Hei Yi Zhuang but not in the Han populations.

Apolipoprotein B gene polymorphisms and serum lipids: meta-analysis of the role of genetic variation in responsiveness to diet

BACKGROUND

The genetic variance determining plasma lipid and lipoprotein concentrations may modify individual responsiveness to alterations in dietary fat and cholesterol content.

OBJECTIVE

The aim was to examine the role of apolipoprotein (apo) B DNA polymorphisms in responsiveness of plasma lipids and lipoproteins to diet.

DESIGN

A controlled dietary intervention study was conducted in 44 healthy, middle-aged subjects with a 3-mo baseline, a 1-mo fat-controlled, a 1-mo high-fat, and a 1-mo habitual diet period. We also conducted a meta-analysis of all published dietary trials, including our own.

RESULTS

In our own dietary study, the apo B XbaI restriction-site polymorphism affected the responsiveness to diet of the plasma LDL-cholesterol concentration (P < 0.05, repeated-measures analysis of variance). Especially during the high-fat diet, homozygous absence of the XbaI restriction site (X(-)/X(-)) was associated with a greater increase in LDL cholesterol (44 +/- 5%) than was X(+)/X(+) (27 +/- 7%) or X(+)/X(-) (40 +/- 5%). The high-fat diet also induced a larger increase in plasma LDL cholesterol in subjects with the R(-)/R(-) genotype (homozygous absence of the EcoRI restriction site) (59 +/- 10%) than in those with the R(+)/R(-) (39 +/- 6%) or R(+)/R(+) (36 +/- 4%) genotype. The M(+)/M(+) genotype (homozygous presence of the MspI restriction site) was also more responsive (41 +/- 3% increase in LDL cholesterol) than the M(+)/M(-) genotype (27 +/- 10% increase). The meta-analysis supported the finding of the significant role of the EcoRI and MspI polymorphisms, but not that of the XbaI polymorphism.

CONCLUSIONS

The present study indicated that the apo B EcoRI and MspI polymorphisms are associated with responsiveness to diet.

Variation of apolipoprotein B as a possible cause of decreased low density lipoprotein clearance and hypercholesterolemia

The fractional catabolic rate (FCR) for low density lipoprotein (LDL) apolipoprotein B (apo B) was studied to explore the variations in apo B as a possible cause of hypercholesterolemia. The FCR of radioiodine labelled autologous LDL and homologous LDL isolated from a normocholesterolemic subject were compared in forty-nine type II hypercholesterolemic males and females with the mean plasma concentration of total cholesterol of 7.78 mmol/l, LDL-cholesterol 5.41 mmol/l and triglycerides 2.09 mmol/l. In most patients the autologous LDL was catabolized at an equal rate and sometimes even faster than the homologous LDL. However, twelve out of forty-nine patients catabolized homologous LDL 0.8-19.3% faster than autologous LDL and several apo B polymorphisms were determined. No apo B-3500 or apo B-3531 mutations were detected. Patients with XbaI -/- (absence of cutting site) had lower total, IDL and LDL cholesterol and LDL apoB than the other genotypes. Patients with EcoRI +/+ (presence of cutting site) had higher total, VLDL and LDL cholesterol and slower FCR for autologous LDL, and their VLDL was richer in cholesterol than that of patients with the EcoRI +/-. The MspI and ins/del polymorphisms were not associated with variations in the measured parameters. The apo E 4 was associated with higher VLDL and IDL cholesterol, higher triglycerides and LDL apo B than E 3/3. Overall, the determined apo B polymorphisms were not related to the slow clearance of autologous LDL among the 12 patients, in whom autologous LDL was cleared at a slower rate than homologous LDL. In conclusion, hypercholesterolemia can be due to particle-related slow clearance of LDL in some patients. However, this is not a common cause of hypercholesterolemia.

Association of an apolipoprotein B gene marker with essential hypertension

We designed an association (retrospective, case control) study aimed at evaluating associations between genetic variations of the human apolipoprotein B (apoB) gene and clinical diagnosis of essential hypertension. Our approach was to compare the distribution of the alleles of a highly polymorphic variable number of tandem repeats localized 3' to the human apoB gene, the apoB 3' hypervariable region (HVR), in a group of normotensive and a group of hypertensive individuals. We collected DNA samples from 437 unrelated nationals (215 normotensives and 222 hypertensives) from the United Arab Emirates (UAEs), and we determined their apoB 3' HVR allele and genotype status with a polymerase chain reaction-based assay. In the UAE population, we found 18 alleles underlying a total of 51 genotypes. The distribution of these alleles was significantly different between normotensive and hypertensive UAE nationals. The main peak of the distributions occurred at 35 repeats among hypertensives (with a relative frequency of 25.7% versus 19.6% in normotensives) and at 37 repeats among normotensives (28.8% versus 20.3% in hypertensives). Alleles with 21, 23, 25, 49, and 55 repeats were found in hypertensives only (with a combined relative frequency of 7.6%). We conclude that variations of the apoB gene, or of a nearby gene, that may be in linkage disequilibrium with these alleles play a role in the development of essential hypertension in the UAEs.

Effect of a synthetic prostaglandin E2 analogue, RS-86505-007, on plasma lipids and lipoproteins in patients with moderate hypercholesterolaemia: efficacy and tolerance of treatment and response in different apolipoprotein polymorphism groups

A double-blind, placebo-controlled ascending dose trial was carried out to evaluate the hypocholesterolaemic efficacy and tolerance of RS-86505-007, a prostaglandin E2 analogue, in moderately hypercholesterolaemic patients. Twenty-four patients received an oral dose of RS-86505-007 3 micrograms t.i.d. and a separate group of 26 patients 6 micrograms t.i.d. for 6 weeks. Plasma total and low-density lipoprotein (LDL) cholesterol concentrations decreased after 2 weeks of treatment, and the reductions were dose dependent. After 6 weeks of treatment (6 micrograms t.i.d.), the reductions from baseline in total and LDL cholesterol concentration were 14.6% and 18.5%, respectively. No changes in the plasma concentration of triglycerides or high-density lipoprotein (HDL) cholesterol were observed. RS-86505-007 tended to reduce total and LDL cholesterol concentrations less in patients with the epsilon 4 allele of the apolipoprotein E than in those with epsilon 3 allele. In contrast, the XbaI or EcoRI polymorphisms of the apolipoprotein B gene seemed to have no effect on the hypocholesterolaemic efficacy of the drug. The drug had no effect on the lipoprotein (a) concentration. Sixty-three percent of patients receiving 3 micrograms t.i.d. and 81% receiving 6 micrograms t.i.d. had adverse events, two-thirds of which related to the gastrointestinal tract. One patient in the 3-micrograms group and three patients in the 6-micrograms group terminated the study prematurely due to adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)