MN blood group affects response of serum LDL cholesterol level to a low fat diet

Association of ABO blood group, Rh phenotype and MN blood group with susceptibility to COVID-19

BACKGROUND

Previous studies have reported that the susceptibility to coronavirus disease 2019 (COVID-19) is related to ABO blood group, but the relationship with Rh phenotype and MN blood group is unknown. China had adopted a strict control policy on COVID-19 until December 5, 2022, when local communities were liberalized. Therefore, we aimed to explore the correlation between ABO blood group, Rh phenotype, MN blood group and susceptibility to COVID-19 based on the time sequence of infection during the pandemic.

METHODS

A total of 870 patients who were routinely hospitalized in Ningbo Medical Center Lihuili Hospital from March 1, 2023 to March 31, 2023 were randomly selected to enroll in this study. Patients were divided into susceptible group and non-susceptible group, according to the time of their previous infection. The demographics and clinical information of the enrolled participants were collected from electronic medical records. The association of ABO blood group, Rh phenotype and MN blood group with susceptibility to COVID-19 was analyzed.

RESULTS

A total of 650 cases (74.7%) had been infected with COVID-19, with 157 cases (18.0%) in the second week and 252 cases (29.0%) in the third week, reaching the peak of infection. Compared with the non-susceptible group, the susceptible group had no statistically significant differences in ABO blood group and Rh phenotype, but the proportion of N+ was higher (75.6% vs 68.9%, P = 0.030) and the proportion of MM was lower (24.4% vs 31.1%, P = 0.030). Consistent with this, ABO blood group and Rh phenotype were not significantly associated with susceptibility to COVID-19 (P>0.05), while N+ and MM were associated with susceptibility to COVID-19 (OR: 1.432, 95% confidence interval [CI]: 1.049, 1.954, P = 0.024; OR: 0.698, 95% CI: 0.512, 0.953, P = 0.024, respectively), after adjusting for age, sex, BMI, basic disease, and vaccination status in multivariate logistic regression analysis.

CONCLUSION

Our study showed that ABO blood group and Rh phenotype may not be related to the susceptibility to COVID-19, but MN blood group may be associated with the susceptibility to COVID-19.

Blood type biochemistry and human disease

Associations between blood type and disease have been studied since the early 1900s when researchers determined that antibodies and antigens are inherited. In the 1950s, the chemical identification of the carbohydrate structure of surface antigens led to the understanding of biosynthetic pathways. The blood type is defined by oligosaccharide structures, which are specific to the antigens, thus, blood group antigens are secondary gene products, while the primary gene products are various glycosyltransferase enzymes that attach the sugar molecules to the oligosaccharide chain. Blood group antigens are found on red blood cells, platelets, leukocytes, plasma proteins, certain tissues, and various cell surface enzymes, and also exist in soluble form in body secretions such as breast milk, seminal fluid, saliva, sweat, gastric secretions, urine, and amniotic fluid. Recent advances in technology, biochemistry, and genetics have clarified the functional classifications of human blood group antigens, the structure of the A, B, H, and Lewis determinants and the enzymes that produce them, and the association of blood group antigens with disease risks. Further research to identify differences in the biochemical composition of blood group antigens, and the relationship to risks for disease, can be important for the identification of targets for the development of nutritional intervention strategies, or the identification of druggable targets. WIREs Syst Biol Med 2016, 8:517-535. doi: 10.1002/wsbm.1355 For further resources related to this article, please visit the WIREs website.

Intersection of genetics and epigenetics in monozygotic twin genomes

As a final function of various epigenetic mechanisms, chromatin regulation is a transcription control process that especially demonstrates active interaction with genetic elements. Thus, chromatin structure has become a principal focus in recent genomics researches that strive to characterize regulatory functions of DNA variants related to diseases or other traits. Although researchers have been focusing on DNA methylation when studying monozygotic (MZ) twins, a great model in epigenetics research, interactions between genetics and epigenetics in chromatin level are expected to be an imperative research trend in the future. In this review, we discuss how the genome, epigenome, and transcriptome of MZ twins can be studied in an integrative manner from this perspective.

Gene-environment interaction on cognition: a twin study of childhood maltreatment and COMT variability

The functional variant Val(158)Met in the coding sequence of COMT gene is involved in the modulation of dopamine availability in the prefrontal cortex in both clinical and general population samples. It has been suggested that the interplay between this genotype and early environmental factors could be used to predict the observed variation in cognitive flexibility. However, other genetic variants and environmental factors may confound the association and produce the inconsistent results commonly found in the literature. In the present study we aimed at testing putative interaction mechanisms between childhood maltreatment and COMT genotypic variability that might explain a proportion of the observed variability of cognitive flexibility in the population. Our design was based on a sample of adult monozygotic twins, which allowed us to test these effects free from potential genetic and shared-environmental confounding factors. Results showed that unique environmental effects of childhood maltreatment significantly impacted cognitive performance among Met/Met subjects. Interestingly, the direction of the association indicated that exposure to early stressful experiences was associated with enhanced cognitive flexibility in this genotype group. These results suggest that COMT may operate as a plasticity gene that provides differential cognitive capacity to respond to environmental stressors.

Blood type diets lack supporting evidence: a systematic review

BACKGROUND

Diets that are based on the ABO blood group system have been promoted over the past decade and claim to improve health and decrease risk of disease. To our knowledge, the evidence to support the effectiveness of blood type diets has not previously been assessed in the scientific literature.

OBJECTIVE

In this current systematic review, published studies that presented data related to blood type diets were identified and critically appraised by using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

DESIGN

A systematic search was performed to answer the following question: In humans grouped according to blood type, does adherence to a specific diet improve health and/or decrease risk of disease compared with nonadherence to the diet? The Cochrane Library, MEDLINE, and Embase were systematically searched by using sensitive search strategies.

RESULTS

Sixteen articles were identified from a total of 1415 screened references, with only one article that was considered eligible according to the selection criteria. The identified article studied the variation between LDL-cholesterol responses of different MNS blood types to a low-fat diet. However, the study did not directly answer the current question. No studies that showed the health effects of ABO blood type diets were identified.

CONCLUSIONS

No evidence currently exists to validate the purported health benefits of blood type diets. To validate these claims, studies are required that compare the health outcomes between participants adhering to a particular blood type diet (experimental group) and participants continuing a standard diet (control group) within a particular blood type population.

Heritabilities of Apolipoprotein and Lipid Levels in Three Countries

This study investigated the influence of genes and environment on the variation of apolipoprotein and lipid levels, which are important intermediate phenotypes in the pathways toward cardiovascular disease. Heritability estimates are presented, including those for apolipoprotein E and AII levels which have rarely been reported before. We studied twin samples from the Netherlands (two cohorts;n= 160 pairs, aged 13–22 andn= 204 pairs, aged 34–62), Australia (n= 1362 pairs, aged 28–92) and Sweden (n= 302 pairs, aged 42–88). The variation of apolipoprotein and lipid levels depended largely on the influences of additive genetic factors in each twin sample. There was no significant evidence for the influence of common environment. No sex differences in heritability estimates for any phenotype in any of the samples were observed. Heritabilities ranged from 0.48–0.87, with most heritabilities exceeding 0.60. The heritability estimates in the Dutch samples were significantly higher than in the Australian sample. The heritabilities for the Swedish were intermediate to the Dutch and the Australian samples and not significantly different from the heritabilities in these other two samples. Although sample specific effects are present, we have shown that genes play a major role in determining the variance of apolipoprotein and lipid levels in four independent twin samples from three different countries.

Low-fat diets for acquired hypercholesterolaemia

BACKGROUND

Hypercholesterolaemia, characterised by raised blood cholesterol levels, is not a disease itself but a metabolic derangement that often contributes to many diseases, notably cardiovascular disease. In most cases, elevated cholesterol levels are associated with high-fat diet, especially saturated fat, coupled with an inactive lifestyle. Less commonly, raised cholesterol may be related to an inherited disorder, familial hypercholesterolaemia. This systematic review is only concerned with acquired hypercholesterolaemia.

OBJECTIVES

To assess the effects of low-fat diets for acquired hypercholesterolaemia and to investigate the incidence of adverse effects from low-fat dietary interventions. We planned to compare the relative effectiveness of low-fat diets with calorie-restricted diets for acquired hypercholesterolaemia. We also wanted to look into the relative effectiveness of low-fat diets and pharmacological interventions for acquired hypercholesterolaemia.

SEARCH STRATEGY

Studies were obtained from computerised searches of The Cochrane Library, MEDLINE, EMBASE and databases of ongoing trials. Date of last search was February 2010.

SELECTION CRITERIA

Otherwise healthy adults (equal to or greater than 18 years) with acquired (not familial) hypercholesterolaemia. We defined hypercholesterolaemia as either total cholesterol greater than 5.2 mmol/L, LDL-cholesterol greater than 3.0 mmol/L, HDL-cholesterol less than 1.0 mmol/L or a combination thereof, although investigators' definitions were also accepted. We wanted to include any low-fat dietary intervention, like low-fat and low-saturated fat diets, intended to lower serum total and LDL-cholesterol or to raise HDL-cholesterol. A low-fat diet was considered as a fat calorie intake less than 20% of the total calories. The minimum duration of the intervention had to be six months. We excluded studies in unhealthy people.

DATA COLLECTION AND ANALYSIS

Two authors were planned to independently assess risk of bias and extract data.

MAIN RESULTS

No study met our inclusion criteria.

AUTHORS' CONCLUSIONS

Well designed, adequately powered randomised controlled trials investigating patient-relevant outcomes of low-fat diets for otherwise healthy people with hypercholesterolaemia are required.

Human nutrition and food research: opportunities and challenges in the post-genomic era

Sequencing of the human genome has opened the door to the most exciting new era for nutritional science. It is now possible to study the underlying mechanisms for diet-health relationships, and in the near future dietary advice (and possibly tailored food products) for promoting optimal health could be provided on an individual basis, in relation to genotype and lifestyle. The role of food in human evolution is briefly reviewed, from palaeolithic times to modern-day hunter-gatherer societies. The aetiology of 'diseases of modern civilization', such as diabetes, heart disease and cancer, and the effect of changes in dietary patterns are discussed. The risk of disease is often associated with common single nucleotide polymorphisms, but the effect is dependent on dietary intake and nutritional status, and is often more apparent in intervention studies employing a metabolic challenge. To understand the link between diet and health, nutritional research must cover a broad range of areas, from molecular to whole body studies, and is an excellent example of integrative biology, requiring a systems biology approach. The annual cost to the National Health Service of diet-related diseases is estimated to be in excess of 15 billion, and although diet is a key component of any preventative strategy, it is not given the prominence it deserves. For example, less than 1% of the pound 1.6 billion budget for coronary heart disease is spent on prevention. The polygenic and multifactorial nature of chronic diseases requires substantial resources but the potential rewards, in terms of quality of life and economics, are enormous. It is timely therefore to consider investing in a long-term coordinated national programme for nutrition research, combining nutritional genomics with established approaches, to improve the health of individuals and of the nation.

Genetic variation and the lipid response to dietary intervention: a systematic review

There is wide interindividual variation in the lipid and lipoprotein responses to dietary change, and the existence of consistent hypo- and hyperresponders supports the hypothesis that responsiveness is related to genetic variation. Many studies have investigated the possibility that the heterogeneity in responsiveness to changes in dietary fat, cholesterol, and fiber intake is explained by variation in genes whose products affect lipoprotein metabolism, eg, apolipoproteins, enzymes, and receptors. A systematic review of the literature was carried out to investigate the effect of genetic variation on the lipid response to dietary intervention. A search strategy for the MEDLINE database retrieved 2540 articles from 1966 to February 2002. This strategy was adapted and performed on the EMBASE database, which retrieved 2473 articles from 1980 to week 9, 2002. Reference lists from relevant journal articles were also checked. This is the first systematic review of the literature, and it summarizes results available from 74 relevant articles. There is evidence to suggest that variation in the genes for apolipoprotein (apo) A-I, apo A-IV, apo B, and apo E contributes to the heterogeneity in the lipid response to dietary intervention. However, the effects of genetic variation are not consistently seen and are sometimes conflicting. Future studies need to have much larger sample sizes based on power calculations and carefully controlled dietary interventions and should investigate the effects of polymorphisms in multiple genes instead of the effects of polymorphisms in single genes.

Biometrical genetics

Biometrical genetics is the science concerned with the inheritance of quantitative traits. In this review we discuss how the analytical methods of biometrical genetics are based upon simple Mendelian principles. We demonstrate how the phenotypic covariance between related individuals provides information on the relative importance of genetic and environmental factors influencing that trait, and how factors such as assortative mating, gene-environment correlation and genotype-environment interaction complicate such interpretations. Twin and adoption studies are discussed as well as their assumptions and limitations. Structural equation modeling (SEM) is introduced and we illustrate how this approach may be applied to genetic problems. In particular, we show how SEM can be used to address complicated issues such as analyzing the causes of correlation between traits or determining the direction of causation (DOC) between variables.

Gene-environment interplay in relation to emotional and behavioral disturbance

The conceptual and methodological issues involved in the study of gene-environment correlations (rGE) and interactions (GxE) are discussed in historical context. Quantitative genetic findings are considered with respect to rGE and GxE in relation to emotional and behavioral disturbance. Key conceptual and substantive implications are outlined in relation to both genetic and environmental risk mediation, with a brief note on evolutionary considerations.

Twins. Novel uses to study complex traits and genetic diseases

The challenge faced by research into the genetic basis of complex disease is to identify genes of small relative effect against a background of substantial genetic and environmental variation. This has focused interest on a classical epidemiological design: the study of twins. Through their precise matching for age, the common family environment and background environmental variation, studying diseases in non-identical twins provides a means to enhance the power of conventional strategies to detect genetic influence through linkage and association. The unique matching of identical twins provides researchers with ways to isolate the function of individual genes involved in disease together with approaches to understanding how genes and the environment interact.

The role of twin studies in the genetics of skin diseases

With advances in molecular biology and statistical techniques, gene discovery is moving at a fast pace. Most skin diseases have a complex mode of inheritance and the twin design is the ideal model to dissect the genetic architecture. Use of the twin pairings in a variety of ways for associations and linkage studies can enhance gene discovery. This review covers the advantages and limitations of the twin method.