A silent mutation of Niemann-Pick C1-like 1 and apolipoprotein E4 modulate cholesterol absorption in primary hyperlipidemias

Alleviation of renal injury in rabbits by allisartan

The objective of this study was to determine the relationship between renal injury and inflammatory response induced by high-fat diet in rabbits and the interventional effect of allisartan. Fifteen 6-week-old healthy male rabbits were randomly divided into three groups: normal control (NC) group, high-lipid diet (HLD) group, high-lipid diet and allisartan (HLD+ALST) group. After allisartan treatment for 12 weeks, changes in total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum creatinine (Scr) and blood urea nitrogen (BUN) were measured enzymatically in the three groups. The left side of the kidney tissue was kept for paraffin section, and HE staining, periodic acid-Schiff (PAS) staining and Masson staining were used to observe the renal pathologic changes. TC, TG, LDL-C, Scr and BUN levels were all higher and HDL-C levels were lower in the HLD group compared with the NC group. Compared with the HLD group, Scr and BUN levels were significantly decreased in the HLD+ALST group. The results of HE staining showed that allisartan improved the changes of renal tissue morphology in rabbits on high-fat diet, reduced glomerular mesangial cell proliferation and improved glomerulosclerosis; PAS staining showed that glomerular glycogen deposition was reduced and glomerular red staining was significantly lighter; Masson staining showed that renal tubular blue-stained collagen fibers were reduced. In conclusion, hyperlipidemia can lead to aberrant expression of multiple cellular proteins and kidney tissue morphological damage in rabbits. On the other hand, allisartan attenuated renal injury and the mechanism may be related to the downregulation of the inflammatory response.

Alleviation of renal injury in rabbits by allisartan

The objective of this study was to determine the relationship between renal injury and inflammatory response induced by high-fat diet in rabbits and the interventional effect of allisartan. Fifteen 6-week-old healthy male rabbits were randomly divided into three groups: normal control (NC) group, high-lipid diet (HLD) group, high-lipid diet and allisartan (HLD+ALST) group. After allisartan treatment for 12 weeks, changes in total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum creatinine (Scr) and blood urea nitrogen (BUN) were measured enzymatically in the three groups. The left side of the kidney tissue was kept for paraffin section, and HE staining, periodic acid-Schiff (PAS) staining and Masson staining were used to observe the renal pathologic changes. TC, TG, LDL-C, Scr and BUN levels were all higher and HDL-C levels were lower in the HLD group compared with the NC group. Compared with the HLD group, Scr and BUN levels were significantly decreased in the HLD+ALST group. The results of HE staining showed that allisartan improved the changes of renal tissue morphology in rabbits on high-fat diet, reduced glomerular mesangial cell proliferation and improved glomerulosclerosis; PAS staining showed that glomerular glycogen deposition was reduced and glomerular red staining was significantly lighter; Masson staining showed that renal tubular blue-stained collagen fibers were reduced. In conclusion, hyperlipidemia can lead to aberrant expression of multiple cellular proteins and kidney tissue morphological damage in rabbits. On the other hand, allisartan attenuated renal injury and the mechanism may be related to the downregulation of the inflammatory response.

Genetic variation and intestinal cholesterol absorption in humans: A systematic review and a gene network analysis

Intestinal cholesterol absorption varies widely between individuals, which may translate into differences in responsiveness to cholesterol-lowering drugs or diets. Therefore, understanding the importance of genetic variation on cholesterol absorption rates and the complex intestinal cholesterol network is important. Based on a systematic review, genetic variants in seven genes (ABCG5, ABCG8, ABO, APOE, MTTP, NPC1L1, and LDLR) were identified that were associated with intestinal cholesterol absorption. No clear associations were found for variants in APOA4, APOB, CETP, CYP7A1, HMGCR, SCARB1, SLCO1B1, and SREBF1. The seven genes were used to construct an intestinal cholesterol absorption network. Finally, a network with fifteen additional genes (APOA1, APOA4, APOB, APOC2, APOC3, CETP, HSPG2, LCAT, LDLRAP1, LIPC, LRP1, OLR1, P4HB, SAR1B, and SDC1) was generated. The constructed network shows that cholesterol absorption is complex. Further studies are needed to validate and improve this network, which may ultimately lead to a better understanding of the wide inter-individual variability in intestinal cholesterol absorption and the development of personalized interventions.

The Bioavailability and Biological Activities of Phytosterols as Modulators of Cholesterol Metabolism

Phytosterols are natural sterols widely found in plants that have a variety of physiological functions, and their role in reducing cholesterol absorption has garnered much attention. Although the bioavailability of phytosterols is only 0.5–2%, they can still promote cholesterol balance in the body. A mechanism of phytosterols for lowering cholesterol has now been proposed. They not only reduce the uptake of cholesterol in the intestinal lumen and affect its transport, but also regulate the metabolism of cholesterol in the liver. In addition, phytosterols can significantly reduce the plasma concentration of total cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL-C), with a dose-response relationship. Ingestion of 3 g of phytosterols per day can reach the platform period, and this dose can reduce LDL-C by about 10.7%. On the other hand, phytosterols can also activate the liver X receptor α-CPY7A1 mediated bile acids excretion pathway and accelerate the transformation and metabolism of cholesterol. This article reviews the research progress of phytosterols as a molecular regulator of cholesterol and the mechanism of action for this pharmacological effect.

Bioavailability of Fat-Soluble Vitamins and Phytochemicals in Humans: Effects of Genetic Variation

Recent data have shown that interindividual variability in the bioavailability of vitamins A (β-carotene), D, and E, and carotenoids (lutein and lycopene), as well as that of phytosterols, is modulated by single nucleotide polymorphisms (SNPs). The identified SNPs are in or near genes involved in intestinal uptake or efflux of these compounds, as well as in genes involved in their metabolism and transport. The phenotypic effect of each SNP is usually low, but combinations of SNPs can explain a significant part of the variability. Nevertheless, results from these studies should be considered preliminary since they have not been validated in other cohorts. Guidelines for future studies are provided to ensure that sound associations are elucidated that can be used to build consolidated genetic scores that may allow recommended dietary allowances to be tailored to individuals or groups by taking into account the multiloci genotypic signature of people of different ethnic origin or even of individuals.

APOE Genotype Influences Postprandial Blood Pressure after High Fat Feeding in Older Adults

OBJECTIVE

Postprandial hypotension (PPH) is a common phenomenon among older adults. The degree to which individuals experience PPH is related to cerebrovascular risk factors and the presence of neurodegenerative diseases such as Alzheimer's disease (AD). Carrier status of the E4 allele of the apolipoprotein E (APOE) gene is a risk factor for AD and influences a variety of responses to metabolic and dietary interventions. However, it is unknown whether APOE genotype influences the risk of PPH and whether type of meal can mediate that response.

DESIGN

Acute meal study with a crossover design.

PARTICIPANTS

32 cognitively healthy older adults with (n=18) and without (n=14) E4+ carrier status.

INTERVENTION

As a part of an ongoing meal study we examined the postprandial blood pressure response after ingestion of a high carbohydrate (HCM) and high fat meal (HFM).

MEASUREMENTS

Blood pressure measurements were taken at 7 time points and change scores, area under the curve (AUC) scores were calculated. Data were analyzed by repeated measures ANOVA as well as Pearson correlation.

RESULTS

Both meals produced a sustained drop in systolic (SBP) and diastolic (DBP) blood pressure, with 37.5% of participants meeting criteria for PPH. Participants carrying the E4+ risk gene experienced a larger decrease in SBP than E4- participants, and this was significantly different after the HFM (E4+ AUC = -30.8 ± 7.6, E4- AUC = -0.2 ± 8.7, p=0.015). Increasing age was associated with a larger drop in postprandial blood pressure but only for the E4+ group after the HFM (p=0.002).

CONCLUSIONS

These data suggest that E4+ individuals experience a greater postprandial blood pressure response particularly following high fat feeding, and this effect becomes more pronounced with age. The prevalence of PPH may play a role in the development of AD and may be mediated by diet.

Genetic polymorphism of sterol transporters in children with future gallstones

BACKGROUND & AIMS

Gallstone disease is related to hypersecretion of cholesterol in bile, and low serum phytosterol levels. We examined how genetic polymorphisms of sterol transporters affect childhood cholesterol metabolism trait predicting adult gallstone disease.

PATIENTS AND METHODS

In retrospective controlled study, we determined D19H polymorphism of ABCG8 gene, genetic variation at Niemann-Pick C1-like 1 (NPC1L1) gene locus (rs41279633, rs17655652, rs2072183, rs217434 and rs2073548), and serum cholesterol, noncholesterol sterols and lipids in children affected by gallstones decades later (n = 66) and controls (n = 126).

RESULTS

In childhood, phytosterols were lower (9.7%-23.4%) in carriers of risk allele 19H compared to 19D homozygotes. Lowest campesterol/cholesterol tertile consisted of 1.9-times more future gallstone subjects, and 3.7-times more 19H carriers than highest one. Campesterol/cholesterol-ratio was highest in 19D homozygote controls, but ∼11% lower in gallstone 19D homozygotes and ∼25% lower among gallstone and control carriers of 19H. Gallstone subjects with alleles CC of rs41279633 and TT of rs217434 of NPC1L1 had ∼18% lower campesterol/cholesterol-ratio compared to mutation carriers.

CONCLUSIONS

Risk trait of cholesterol metabolism (low phytosterols) in childhood favouring cholesterol gallstone disease later in adulthood is influenced by risk variant 19H of ABCG8 and obviously also other factors. NPC1L1 variants have minor influence on noncholesterol sterols.

Effect of Ezetimibe Monotherapy on Low-Density Lipoprotein Cholesterol and on Markers of Cholesterol Synthesis and Absorption in Japanese Patients With Hypercholesterolemia

Background

The aim of this study was to evaluate effect of ezetimibe monotherapy on serum low-density lipoprotein cholesterol (LDL-C) in Japanese patients and to investigate the association between changes of LDL-C and changes of markers for cholesterol synthesis and absorption.

Methods

Seventy-six hypercholesterolemic patients without statin therapy were enrolled and randomized to two groups, which were an ezetimibe group (group E, n = 44) and a control group without ezetimibe treatment that received diet therapy alone (group C, n = 32). The study period was 12 weeks. In group E, 10 mg of ezetimibe was administered daily after breakfast. Serum lipids were measured every 4 weeks, while lathosterol (a cholesterol synthesis marker) and campesterol and sitosterol (cholesterol absorption markers) were examined at baseline and at 12 weeks.

Results

A significant reduction of LDL-C was observed in group E at both 4 and 12 weeks (from 155 ± 3.9 to 128 ± 3.4 mg/dL and 132 ± 3.9 mg/dL, respectively, both P < 0.01), associated with an increase of high-density lipoprotein cholesterol (HDL-C)at 12 weeks (from 53 ± 1.3 to 55 ± 1.5 mg/dL, P < 0.05) and no change of triglycerides. In contrast, none of these lipids changed in group C. An increase of lathosterol and a decrease of campesterol and sitosterol were observed in group E, while none of these markers changed in group C. When group E was divided into two subgroups according to the reduction of LDL-C, which were a good response group (reduction ≥ 20 mg/dL, ΔLDL-C = -27.9 ± 1.3 mg/dL, n = 18) and a poor response group (reduction < 20 mg/dL, ΔLDL-C = -3.7 ± 2.5 mg/dL, n = 26), baseline levels of campesterol and sitosterol were higher in the good response group.

Conclusion

Ezetimibe monotherapy reduced LDL-C and increased HDL-C, with the reduction of LDL-C being greater in patients with higher levels of cholesterol absorption markers.

The NPC1L1 Polymorphism 1679C>G Is Associated with Gallstone Disease in Chinese Patients

Niemann Pick Type C1 Like 1 (NPC1L1) protein plays a key role in intestinal and hepatic cholesterol metabolism in humans. Genetic variation in NPC1L1 has been widely studied in recent years. We analyzed NPC1L1 single nucleotide polymorphisms in Chinese gallstone disease patients to investigate their association with gallstone disease. NPC1L1 mRNA expression was also measured in liver biopsies from patients with cholesterol gallstone disease and compared between genotypes. The G allele of the g1679C>G (rs2072183) polymorphism was significantly more prevalent in patients with gallstones compared with gallstone-free subjects. Moreover, patients carrying the G allele had lower hepatic NPC1L1 mRNA expression and higher biliary cholesterol (molar percentages) and cholesterol saturation index. Our study suggests that the G allele of the NPC1L1 polymorphism g1679C>G may be a positive marker of gallstone formation risk.

Apolipoprotein E (Apo E) gene polymorphisms and recurrent pregnancy loss: a meta-analysis

BACKGROUND

Recently, a relationship between recurrent pregnancy loss (RPL) and Apolipoprotein E (Apo E) gene polymorphisms has been proposed. In order to investigate the real association between Apo E polymorphisms and RPL, our meta-analysis was carried out.

METHODS

We estimated the association with RPL risk under dominant and recessive models, in combination with the OR and RR with a 95% confidence interval (CI), which was used to assess the association between RPL and Apo E polymorphisms.

RESULTS

According to our criterion, there were 6 studies included. The dominant model used the E4/E3 group and the OR was 1.919 (95 %CI: 1.016-3.625, I(2) = 53.8%), the RR was 1.308 (95%Cl: 1.071-1.598) suggesting that carriers of the E4 allele would have a higher risk of causing spontaneous miscarriages. In addition, the OR was 0.727 (95%CI: 0.566-0.932, I(2) = 0.0%) and RR was 0.923 (95%CI: 0.867-0.982) in a fixed model for E3/E3 homozygotes versus other genotypes, suggesting that the Apo E3 polymorphism could be a protective factor. The OR was 1.365 (95% CI: 1.029-1.811, I(2) = 0 .0%) in a fixed model comparing the E2 allele with the E3 allele, suggesting that Apo E2 polymorphisms may contribute to RPL as a risk factor. Furthermore, after conducting sensitivity analysis in the E4/E3 group, the results showed this to be consistent and the OR was 2.249 (95%CI: 1.474-3.431).

CONCLUSIONS

There is a close association between RPL and Apo E gene polymorphisms. For RPL, the Apo E4 polymorphism could be a risk factor, the Apo E3 polymorphism may be a protective factor and the Apo E2 polymorphism may be another potential risk factor.