Longer Duration and Earlier Age of Onset of Paternal Betel Chewing and Smoking Increase Metabolic Syndrome Risk in Human Offspring, Independently, in a Community-Based Screening Program in Taiwan

Metabolic profiles of children aged 2-5 years born after frozen and fresh embryo transfer: A Chinese cohort study

BACKGROUND

Frozen embryo transfer (FET) has become a widely employed assisted reproductive technology technique. There have historically been concerns regarding the long-term metabolic safety of FET technology in offspring due to pregnancy-induced hypertension and large for gestational age, both of which are well-recognized factors for metabolic dysfunction of children. Therefore, we aimed to compare the metabolic profiles of children born after frozen versus fresh embryo transfer at 2 to 5 years of age.

METHODS AND FINDINGS

This was a prospective cohort study. Using data from the "Assisted Reproductive Technology borned KIDs (ARTKID)," a birth cohort of offspring born from assisted reproductive technology at the Institute of Women, Children and Reproductive Health, Shandong University, China. We included 4,246 singletons born after FET (n = 2,181) and fresh embryo transfer (n = 2,065) enrolled between 2008 and 2019 and assessed the glucose and lipid variables until the age of 2 to 5 years. During a mean follow-up of 3.6 years, no significant differences were observed in fasting blood glucose, fasting insulin, Homeostatic Model Assessment of Insulin Resistance Index, total cholesterol, triglycerides, low-density lipoprotein-cholesterol, and high-density lipoprotein-cholesterol levels between offspring conceived by fresh and frozen embryo transfer in the crude model and adjusted model (adjusted for parental age, parental body mass index, parental education level, paternal smoking, parity, offspring age and sex). These results remained consistent across subgroup analyses considering offspring age, the stage of embryo transfer, and the mode of fertilization. Results from sensitivity analysis on children matched for age within the cohort remains the same. The main limitation of our study is the young age of the offspring.

CONCLUSIONS

In this study, the impact of FET on glucose and lipid profiles during early childhood was comparable to fresh embryo transfer. Long-term studies are needed to evaluate the metabolic health of offspring born after FET.

A systematic scientometric review of paternal inheritance of acquired metabolic traits

BACKGROUND

The concept of the inheritance of acquired traits, a foundational principle of Lamarck's evolutionary theory, has garnered renewed attention in recent years. Evidence for this phenomenon remained limited for decades but gained prominence with the Överkalix cohort study in 2002. This study revealed a link between cardiovascular disease incidence and the food availability experienced by individuals' grandparents during their slow growth periods, reigniting interest in the inheritance of acquired traits, particularly in the context of non-communicable diseases. This scientometric analysis and systematic review comprehensively explores the current landscape of paternally transmitted acquired metabolic traits.

RESULTS

Utilizing Scopus Advanced search and meticulous screening, we included mammalian studies that document the inheritance or modification of metabolic traits in subsequent generations of unexposed descendants. Our inclusive criteria encompass intergenerational and transgenerational studies, as well as multigenerational exposures. Predominantly, this field has been driven by a select group of researchers, potentially shaping the design and focus of existing studies. Consequently, the literature primarily comprises transgenerational rodent investigations into the effects of ancestral exposure to environmental pollutants on sperm DNA methylation. The complexity and volume of data often lead to multiple or redundant publications. This practice, while understandable, may obscure the true extent of the impact of ancestral exposures on the health of non-exposed descendants. In addition to DNA methylation, studies have illuminated the role of sperm RNAs and histone marks in paternally acquired metabolic disorders, expanding our understanding of the mechanisms underlying epigenetic inheritance.

CONCLUSIONS

This review serves as a comprehensive resource, shedding light on the current state of research in this critical area of science, and underscores the need for continued exploration to uncover the full spectrum of paternally mediated metabolic inheritance.

Parental exposure to famine in early life and child overweight in offspring in Chinese populations

BACKGROUND

Little is known about the transgenerational effect of nutrition deficiency in early life. This study aimed to evaluate the associations of fetal and childhood exposure to famine of parents with their offspring's risk of overweight during childhood.

METHODS

This analysis included a total of 3734 participants of the China Health and Nutrition Survey aged 1-17 years whose fathers and/or mothers were born in 1955-1966. These children were classified into subgroups according to parental famine exposure status (unexposed and exposed) and timing (fetal-exposed and childhood-exposed). Random effects models were applied to evaluate the associations of parental famine exposure with body mass index (BMI) and overweight of offspring. Fractional polynomial functions were adopted to describe trajectories of BMI against age.

RESULTS

Compared with children of unexposed parents, there was a lower risk of overweight among offspring of childhood-exposed fathers [OR (95%CI): 0.80 (0.61, 1.04)] or exposed parents [0.84 (0.68, 1.04)], particularly among male offspring, but not among those with exposed mothers only [0.98 (0.65, 1.47)]. For BMI, children with exposed mothers only had a slightly higher BMI [β(95%CI): 0.17 (-0.15, 0.49)], while those with exposed fathers only had no difference [-0.02 (-0.23, 0.19)] or exposed parents had a slightly lower BMI [-0.17 (-0.33, 0.00)] (p < 0.05 for interaction between maternal and paternal exposures). Stratified analysis showed little heterogeneity between male and female offspring, but the association between paternal childhood exposure to famine and lower overweight risk in offspring was more evident in high (vs low) paternal education group (p for interaction< 0.05).

CONCLUSIONS

The transgenerational associations of early-life exposure to famine with lower risks of child overweight may be via the paternal line and differ by the educational levels of parents. Further studies are warranted to confirm the results and reveal the biological mechanisms underlying.

Vitamin D deficiency in British South Asians, a persistent but avoidable problem associated with many health risks (including rickets, T2DM, CVD, COVID-19 and pregnancy complications): the case for correcting this deficiency

High vitamin D deficiency rates, with rickets and osteomalacia, have been common in South Asians (SAs) arriving in Britain since the 1950s with preventable infant deaths from hypocalcaemic status-epilepticus and cardiomyopathy. Vitamin D deficiency increases common SA disorders (type 2 diabetes and cardiovascular disease), recent trials and non-linear Mendelian randomisation studies having shown deficiency to be causal for both disorders. Ethnic minority, obesity, diabetes and social deprivation are recognised COVID-19 risk factors, but vitamin D deficiency is not, despite convincing mechanistic evidence of it. Adjusting analyses for obesity/ethnicity abolishes vitamin D deficiency in COVID-19 risk prediction, but both factors lower serum 25(OH)D specifically. Social deprivation inadequately explains increased ethnic minority COVID-19 risks. SA vitamin D deficiency remains uncorrected after 70 years, official bodies using 'education', 'assimilation' and 'diet' as 'proxies' for ethnic differences and increasing pressures to assimilate. Meanwhile, English rickets was abolished from ~1940 by free 'welfare foods' (meat, milk, eggs, cod liver oil), for all pregnant/nursing mothers and young children (<5 years old). Cod liver oil was withdrawn from antenatal clinics in 1994 (for excessive vitamin A teratogenicity), without alternative provision. The take-up of the 2006 'Healthy-Start' scheme of food-vouchers for low-income families with young children (<3 years old) has been poor, being inaccessible and poorly publicised. COVID-19 pandemic advice for UK adults in 'lockdown' was '400 IU vitamin D/day', inadequate for correcting the deficiency seen winter/summer at 17.5%/5.9% in White, 38.5%/30% in Black and 57.2%/50.8% in SA people in representative UK Biobank subjects when recruited ~14 years ago and remaining similar in 2018. Vitamin D inadequacy worsens many non-skeletal health risks. Not providing vitamin D for preventing SA rickets and osteomalacia continues to be unacceptable, as deficiency-related health risks increase ethnic health disparities, while abolishing vitamin D deficiency would be easier and more cost-effective than correcting any other factor worsening ethnic minority health in Britain.

Long-term exposure to air pollutants and increased risk of chronic kidney disease in a community-based population using a fuzzy logic inference model

Background

Fuzzy inference systems (FISs) based on fuzzy theory in mathematics were previously applied to infer supplementary points for the limited number of monitoring sites and improve the uncertainty of spatial data. Therefore we adopted the FIS method to simulate spatiotemporal levels of air pollutants [particulate matter <2.5 μm (PM_2.5), sulfur dioxide (SO₂) and (NO₂)] and investigated the association of levels of air pollutants with the community-based prevalence of chronic kidney disease (CKD).

Methods

A Complex Health Screening program was launched during 2012–2013 and a total of 8284 community residents in Chiayi County, which is located in southwestern Taiwan, received a series of standard physical examinations, including measurement of estimated glomerular filtration rate (eGFR). CKD cases were defined as eGFR <60 mL/min/1.73 m² and were matched for age and gender in a 1:4 ratio of cases:controls. Data on air pollutants were collected from air quality monitoring stations during 2006–2016. The longitude, latitude and recruitment month of the individual case were entered into the trained FIS. The defuzzification process was performed based on the proper membership functions and fuzzy logic rules to infer the concentrations of air pollutants. In addition, we used conditional logistic regression and the distributed lag nonlinear model to calculate the prevalence ratios of CKD and the 95% confidence interval. Confounders including Framingham Risk Score (FRS), diabetes, gout, arthritis, heart disease, metabolic syndrome and vegetables consumption were adjusted in the models.

Results

Participants with a high FRS (>10%), diabetes, heart disease, gout, arthritis or metabolic syndrome had significantly increased CKD prevalence. After adjustment for confounders, PM_2.5 levels were significantly increased in CKD cases in both single- and two-pollutant models (prevalence ratio 1.31–1.34). There was a positive association with CKD in the two-pollutant models for NO₂. However, similar results were not observed for SO₂.

Conclusions

FIS may be helpful to reduce uncertainty with better interpolation for limited monitoring stations. Meanwhile, long-term exposure to ambient PM_2.5 appears to be associated with an increased prevalence of CKD, based on a FIS model.

Paternal body mass index before conception associated with offspring's birth weight in Chinese population: a prospective study

Whether paternal epigenetic changes resulting from nutrition might be inherited by their offspring remains unknown. This study evaluated the relationship between preconception paternal body weight and their offspring's birth weight in 1,810 Chinese mother-father-baby trios. Information on paternal and maternal preconception body weight and height was collected via a self-reported questionnaire. Birth weight was collected from medical records. Paternal preconception body weight was associated with offspring's birth weight (p trend = .02) after multivariate adjustment. Each standard deviation increment of paternal body mass index was associated with an additional 29.6 g increase of birth weight (95% confident interval: 5.7 g, 53.5 g). The association was more pronounced in male neonates, and neonates with overweight mothers, and with mothers who gained excessive gestational weight, compared to their counterparts (all p interaction < .05). Sensitivity analyses showed similar pattern to that of the main analysis. Paternal preconception body weight was associated with birth weight of their offspring.Impact statementWhat is already known on this subject? More efforts have previously been put on the maternal contribution to birth weight, however, it is uncertain whether paternal pre-conceptional body weight, an indicator for epigenetic information, might be inherited by their offspring.What do the results of this study add? In the current study that included 1,810 Chinese mother-father-baby trios, a small but significant association was observed between paternal preconception body weight and offspring's birth weight (p trend =.02).What are the implications of these findings for clinical practice and/or further research? Paternal epigenetic information of nutrition could be inherited by their offspring.

Areca catechu-(Betel-nut)-induced whole transcriptome changes in a human monocyte cell line that may have relevance to diabetes and obesity; a pilot study

BACKGROUND

Betel-nut consumption is the fourth most common addictive habit globally and there is good evidence linking the habit to obesity, type 2 diabetes (T2D) and the metabolic syndrome. The aim of our pilot study was to identify gene expression relevant to obesity, T2D and the metabolic syndrome using a genome-wide transcriptomic approach in a human monocyte cell line incubated with arecoline and its nitrosated products.

RESULTS

The THP1 monocyte cell line was incubated separately with arecoline and 3-methylnitrosaminopropionaldehyde (MNPA) in triplicate for 24 h and pooled cDNA indexed paired-end libraries were sequenced (Illumina NextSeq 500). After incubation with arecoline and MNPA, 15 and 39 genes respectively had significant changes in their expression (q < 0.05, log fold change 1.5). Eighteen of those genes have reported associations with T2D and obesity in humans; of these genes there was most marked evidence for CLEC10A, MAPK8IP1, NEGR1, NQ01 and INHBE genes.

CONCLUSIONS

Our preliminary studies have identified a large number of genes relevant to obesity, T2D and metabolic syndrome whose expression was changed significantly in human TPH1 cells following incubation with betel-nut derived arecoline or with MNPA. These findings require validation by further cell-based work and investigation amongst betel-chewing communities.

Cohort-based analysis of paternal opioid use in relation to offspring's BMI and plasma lipid profile

A growing body of evidence suggests that opioid use may affect consumer’s offspring by second-hand passive smoke exposure, as well as by transgenerational impacts mediated by genetic and epigenetic alterations of paternal gametes. In human studies, these effects are limited to investigating the neural, behavioral and cognitive characteristics of offspring. Only animal studies have investigated the metabolic parameters influenced by passive opium smoke exposure. Here, we conducted population-based analyses aimed to estimate the association of paternal opioid consumption, started before or after child birth, with BMI status and plasma lipid profile of young adult offspring. The present study includes 840 parents-offspring trios (offspring aged 15–35, parents aged 35–70) who participated in the prospective Rafsanjan Cohort Study (RCS)—a city in the south-east of Iran—as one of the district areas of the PERSIAN cohort (Prospective Epidemiological Research Studies in IrAN). All procedures for interviews, anthropometric measurements and physical examinations, biological sample collection and laboratory tests for blood biochemical parameters were conducted according to the PERSIAN cohort protocol, and in the well-established RCS setting. Crude and adjusted multiple logistic regression analysis were conducted to assess the relationship of paternal regular opioid use with offspring’s BMI status, and plasma lipid factors. The prevalence of fathers who use opioids regularly among the studied trios was 42.8% (360/840). Our regression analyses demonstrated that paternal opioid use started pre-fatherhood is associated with 76% higher adjusted odds ratio (OR) of overweight/obesity in young offspring (adjusted OR 1.76 (95% CI 1.15–2.71)), adjusting for sex, age, parental BMIs, paternal smoking status and socioeconomic status index (WSI). This relationship persisted when fathers who used opioid by routes other than inhaling (oral) were excluded from logistic analysis (adjusted OR 1.73 (95% CI 1.12–2.68)). Interestingly, sex stratified analysis displayed a 201% increased odds ratio of overweight/obesity in sons of fathers who use opioid regularly, started after child birth (Adjusted OR 3.01 (95% CI 1.68–5.39), while no significant association was found in daughters (adjusted OR 0.74 (95% CI 0.35–1.54)). Additionally, increasing exposure–response relationships were observed between odds ratios of overweight/obesity and the number of years of paternal opioid use after birth (p-trend = 0.0008). Paternal regular opioid use started pre-fatherhood was associated with 54% lowered risk of underweight [adjusted OR 0.46 (95% CI 0.24–0.86)]. Finally, paternal opioid consumption started either before or after child birth did not show a significant association with the high level of the three parameters of plasma lipid factors (triglyceride, cholesterol and HDL-cholesterol) in offspring. Our results suggest that the environmental impacts of paternal regular opioid use may be sufficient to make an effect on male offspring metabolism independent of genetic and epigenetic impact on gametes.

Impact of Parental Exposure on Offspring Health in Humans

The possibility that parental life experiences and environmental exposures influence mental and physical health across generations is an important concept in biology and medicine. Evidence from animal models has established the existence of a non-genetic mode of inheritance. This form of heredity involves transmission of the effects of parental exposure to the offspring through epigenetic changes in the germline. Studying the mechanisms of epigenetic inheritance in humans is challenging because it is difficult to obtain multigeneration cohorts, to collect reproductive cells in exposed parents, and to exclude psychosocial and cultural confounders. Nonetheless, epidemiological studies in humans exposed to famine, stress/trauma, or toxicants have provided evidence that parental exposure can impact the health of descendants, in some cases, across several generations. A few studies have also started to reveal epigenetic changes in the periphery and sperm after certain exposures. This article reviews these studies and evaluates the current evidence for the potential contribution of epigenetic factors to heredity in humans. The challenges and limitations of this fundamental biological process, its implications, and its societal relevance are also discussed.

Association between Dietary Habits, Shift Work, and the Metabolic Syndrome: The Korea Nurses' Health Study

Metabolic syndrome (MetS) is an important public health problem, and unhealthy dietary habits and shift work are considered major factors that increase the prevalence of MetS. The purpose of this study was to examine whether dietary habits, alcohol drinking, and shift-working were associated with development of MetS in shift-working female nurses. This study analyzed cross-sectional survey data from the Korea Nurses’ Health Study (KNHS). Of the 1638 nurses, 403 participants were selected based on the propensity score matching method (PSM). These participants had either no or more than three MetS determinant factors. Analysis was conducted by using multivariable logistic regression to confirm the factors influencing MetS. The prevalence of MetS in this group (1638 participants) was 5.6% (92 participants). Consumption of over 50% of daily calorie intake after 7 p.m., consumption of carbonated drinks, family history of diabetes, and non-shift work were significant factors influencing MetS. Nurses are one of the at-risk groups for unhealthy dietary habits due to the nature of their work. Therefore, nurse managers should include regular dietary education for nurses and continue their policy efforts to resolve health problems that may arise in connection with nurses’ work.

Betel Quid Health Risks of Insulin Resistance Diseases in Poor Young South Asian Native and Immigrant Populations

Betel quid, traditionally prepared with areca nut, betel leaf, and slaked lime, has been consumed for thousands of years, mainly in the form of chewing. Originally used for cultural, medicinal, and ceremonial purposes mainly in South Asian countries, its use has recently spread across the globe due to its psychoactive, euphoric, and aphrodisiac properties. Now it is widely used as a social lubricant and source of financial profit. Unfortunately, the profit motive has led to high rates of habitual consumption with eventual conversion to addiction among young girls and boys. Moreover, the worrisome practice of including tobacco in quid preparations has grown, particularly among pregnant women. Major health concerns include increased rates of malignancy, oral pathology, and cardiovascular, hepatic, fertility, metabolic, and neuropsychiatric disorders. Metabolic disorders and insulin resistance disease states such as type 2 diabetes, obesity, and metabolic syndrome contribute to cognitive decline and neurodegeneration. Mechanistically, the constituents of areca nut/betel quid are metabolized to N-nitroso compounds, i.e., nitrosamines, which are carcinogenic at high doses and cause insulin resistance following chronic low-level exposures. From an epidemiological perspective, the rising tide of insulin resistance diseases including obesity, diabetes, and dementias that now disproportionately burden poor countries has been propagated by rapid commercialization and enhanced access to betel quid. Public health measures are needed to impose socially and ethically responsible barriers to yet another cause of global health disparity.

Intolerance of loud sounds in childhood: Is there an intergenerational association with grandmaternal smoking in pregnancy?

Recent research using the Avon Longitudinal Study of Parents and Children (ALSPAC) demonstrated an association between maternal grandmother smoking in pregnancy and the autistic traits of impaired social communication and repetitive behaviour in granddaughters but not grandsons, but of paternal grandmother smoking and early development of myopia in the grandchild. Here we investigate whether grandmaternal smoking in pregnancy is associated with intolerance to loud sounds. ALSPAC collected information during the index pregnancy from the study parents on the smoking habits, social and other features of their own parents. Maternal report when the child was aged 6 and 13 included hating loud sounds; at age 11 the child was tested for volume preference for listening to music through headphones. Statistical analysis compared results for grandchildren in relation to whether a parent had been exposed in utero to maternal smoking, adjusted for their grandparents’ social and demographic attributes. We hypothesised that there would be sex differences in the effects of grandmaternal prenatal smoking, based on previous intergenerational studies. For 6-year-old children maternal report of intolerance to loud noise was more likely in grandsons if the maternal grandmother had smoked [adjusted odds ratio (AOR) 1.27; 95% confidence interval (CI) 1.03,1.56; P = 0.025], but less likely in girls [AOR 0.82; 95%CI 0.63,1.07] P_interaction <0.05. If the paternal grandmother had smoked the grandchildren were less likely to be intolerant, especially girls. The objective measure of choice of volume for music through headphones showed that grandsons of both maternal and paternal smoking grandmothers were less likely to choose high volumes compared with granddaughters (P<0.05). In line with our prior hypothesis of sex differences, we showed that grandsons were more intolerant of loud sounds than granddaughters particularly at age 6, and this was confirmed by objective measures at age 11.

Stress resilience in young men mediates the effect of childhood trauma on their offspring's birth weight - An analysis of 250,000 families

Experiencing the death of a parent during childhood is a severe trauma that seems to affect the next generation's birth weight. We studied the consequences of parental loss during childhood for men's psychological and physiological characteristics at age 18, and whether these were important for their first-born offspring's birth outcomes. We used a structured life-course approach and four-way decomposition analysis to analyse data for 250,427 three-generation families retrieved from nationwide Swedish registers and found that psychological resilience was impaired and body mass index was higher in men who had experienced parental death. Both characteristics were linked to offspring birth weight. This was lower by 18.0 g (95% confidence interval: 5.7, 30.3) for men who lost a parent at ages 8-17 compared to other ages. Resilience mediated 40% of this influence. Mediation by body mass index, systolic and diastolic blood pressure was negligible, as was the effect of parental loss on length of gestation. There was no mediation by the education of the men's future spouse. Previous literature has indicated that the period before puberty, the "slow growth period", is sensitive. Our evidence suggests that this may be too narrow a restriction: boys aged 8-17 appear to be particularly likely to respond to parental loss in a way which affects their future offspring's birth weight. We conclude that the observed transgenerational influence on birth weight is mediated by the father's psychological resilience but not by his body mass index or blood pressure.

Paternal Programming of Liver Function and Lipid Profile Induced by a Paternal Pre-Conceptional Unhealthy Diet: Potential Association with Altered Gut Microbiome Composition

BACKGROUND/AIMS

Paternal exposure to adverse environmental conditions can act on offspring's phenotype and influence offspring's later life disease risk. Our study was designed to examine the effect of feeding male rats before mating a high-fat, high-sucrose and high-salt diet (HFSSD) over two generations (F0 and F1) on their offspring's (F2) liver function and gut microbiome composition.

METHODS

Male F0 rats and male F1 rats were fed either control diet or HFSSD before mating. Liver function of F2 offspring was investigated, and their gut microbiome composition was analyzed by 16S rRNA gene sequencing in the F2 offspring of rats whose fathers and grandfathers were fed with control diet (CD) (F0CD+F1CD-F2 group) or HFSSD prior to mating (F0HD+F1HD-F2 group).

RESULTS

F2 offspring had higher serum aspartate aminotransferase activity (female, p < 0.05 and male, p < 0.01 respectively) compared with control. Shannon indexes of gut microbiota indicated a significantly higher diversity in the female F0HD+F1HD-F2 as compared to F0CD+F1CD-F2 female offspring (p < 0.01). The dominant phyla of all the groups were Bacteroidetes, Firmicutes and Proteobacteria. There were significant differences in gut bacterial community composition at phyla and genus level between the F0CD+F1CD-F2 and F0HD+F1HD-F2. Furthermore, the variation in the relative abundance (percentage) of bacterial genus in the F2 offspring was associated with liver function alterations induced by a paternal pre-conceptional unhealthy diet. Male F0HD+F1HD-F2 offspring had higher serum cholesterol, high density lipoproteins as well as low density lipoproteins concentrations compared to the corresponding male control rats.

CONCLUSION

Taken together, our findings suggested that a paternal pre-conceptional unhealthy diet predisposes the offspring to mild liver function alterations and alterations of gut microbiota in later life. Effects on lipids were sex-specific and only seen in male offspring.

Vitamin D status and its management for achieving optimal health benefits in the elderly

INTRODUCTION

Vitamin D deficiency is common, world-wide, but vitamin D repletion throughout life, and into older age, has accepted health benefits for bone. Many mechanisms through which vitamin D also benefits soft tissues are understood, and clinical evidence of such benefits is now accumulating, especially following re-analyses of trial data, which are revealing previously missed health benefits with correction of deficiency.

AREAS COVERED

The sources of vitamin D, its activation, mechanistic effects; problems of trials of supplementation for reducing health risks, the benefits shown for mortality, cardiovascular disease, infection and cancer; the global problem of vitamin D deficiency; age-related reductions in vitamin D efficacy, and currently recommended intakes.

EXPERT COMMENTARY

High prevalence of vitamin D deficiency and insufficiency worldwide have proven ill-effects on health. Governmental efforts to improve population repletion by recommending minimal daily intakes does benefit some but is not effective at the population-level. However, food fortification with vitamin D3, already implemented in some countries, can solve this highly avoidable problem cost-effectively and is probably the best way to abolish vitamin D inadequacy, allowing public health benefits to emerge over time, thereby allowing future research on vitamin D to be directed at emerging issues on vitamin D.

An overview of type 2 diabetes and importance of vitamin D3-vitamin D receptor interaction in pancreatic β-cells

One significant health issue that plagues contemporary society is that of Type 2 diabetes (T2D). This disease is characterised by higher-than-average blood glucose levels as a result of a combination of insulin resistance and insufficient insulin secretions from the β-cells of pancreatic islets of Langerhans. Previous developmental research into the pancreas has identified how early precursor genes of pancreatic β-cells, such as Cpal, Ngn3, NeuroD, Ptf1a, and cMyc, play an essential role in the differentiation of these cells. Furthermore, β-cell molecular characterization has also revealed the specific role of β-cell-markers, such as Glut2, MafA, Ins1, Ins2, and Pdx1 in insulin expression. The expression of these genes appears to be suppressed in the T2D β-cells, along with the reappearance of the early endocrine marker genes. Glucose transporters transport glucose into β-cells, thereby controlling insulin release during hyperglycaemia. This stimulates glycolysis through rises in intracellular calcium (a process enhanced by vitamin D) (Norman et al., 1980), activating 2 of 4 proteinases. The rise in calcium activates half of pancreatic β-cell proinsulinases, thus releasing free insulin from granules. The synthesis of ATP from glucose by glycolysis, Krebs cycle and oxidative phosphorylation plays a role in insulin release. Some studies have found that the β-cells contain high levels of the vitamin D receptor; however, the role that this plays in maintaining the maturity of the β-cells remains unknown. Further research is required to develop a more in-depth understanding of the role VDR plays in β-cell function and the processes by which the beta cell function is preserved.

Does cross-generational epigenetic inheritance contribute to cultural continuity?

Human studies of cross-generational epigenetic inheritance have to consider confounding by social patterning down the generations, often referred to as 'cultural inheritance'. This raises the question to what extent is 'cultural inheritance' itself epigenetically mediated rather than just learnt. Human studies of non-genetic inheritance have demonstrated that, beyond foetal life, experiences occurring in mid-childhood before puberty are the most likely to be associated with cross-generational responses in the next generation(s). It is proposed that cultural continuity is played out along the axis, or 'payoff', between responsiveness and stability. During the formative years of childhood a stable family and/or home permits small children to explore and thereby learn. To counter disruptions to this family home ideal, cultural institutions such as local schools, religious centres and market places emerged to provide ongoing stability, holding the received wisdom of the past in an accessible state. This cultural support allows the growing child to freely indulge their responsiveness. Some of these prepubertal experiences induce epigenetic responses that also transfer molecular signals to the gametes through which they contribute to the conception of future offspring. In parallel co-evolution with growing cultural support for increasing responsiveness, 'runaway' responsiveness is countered by the positive selection of genetic variants that dampen responsiveness. Testing these ideas within longitudinal multigenerational cohorts will need information on ancestors/parents' own communities and experiences (Exposome scans) linked to ongoing Phenome scans on grandchildren; coupled with epigenome analysis, metastable epialleles and DNA methylation age. Interactions with genetic variants affecting responsiveness should help inform the broad hypothesis.

Transgenerational epigenetics: Integrating soma to germline communication with gametic inheritance

Evidence supporting germline mediated epigenetic inheritance of environmentally induced traits has increasingly emerged over the past several years. Although the mechanisms underlying this inheritance remain unclear, recent findings suggest that parental gamete-borne epigenetic factors, particularly RNAs, affect post-fertilization and developmental gene regulation, ultimately leading to phenotypic appearance in the offspring. Complex processes involving gene expression and epigenetic regulation are considered to perpetuate across generations. In addition to transfer of germline factors, epigenetic inheritance via gametes also requires a mechanism whereby the information pertaining to the induced traits is communicated from soma to germline. Despite violating a century-old view in biology, this communication seems to play a role in transmission of environmental effects across generations. Circulating RNAs, especially those associated with extracellular vesicles like exosomes, are emerging as promising candidates that can transmit gene regulatory information in this direction. Cumulatively, these new observations provide a basis to integrate epigenetic inheritance. With significant implications in health, disease and ageing, the latter appears poised to revolutionize biology.