Human Epidemiological Studies Research Articles

The impact of excessive maternal weight on the risk of neuropsychiatric disorders in offspring-a narrative review of clinical studies.

The global prevalence of overweight and obesity is a significant public health concern that also largely affects women of childbearing age. Human epidemiological studies indicate that prenatal exposure to excessive maternal weight or excessive gestational weight gain is linked to various neurodevelopmental disorders in children, including attention deficit hyperactivity disorder, autism spectrum disorder, internalizing and externalizing problems, schizophrenia, and cognitive/intellectual impairment. Considering that inadequate maternal body mass can induce serious disorders in offspring, it is important to increase efforts to prevent such outcomes. In this paper, we review human studies linking excessive maternal weight and the occurrence of mental disorders in children.

Viruses as a potential environmental trigger of type 1 diabetes mellitus (Review).

The etiopathogenesis of type 1 diabetes mellitus (T1DM) is a complex multifactorial process that involves an intricate network of genetic, epigenetic, immunological, and environmental factors. Despite the advances in recent years, some aspects of the mechanisms involved in triggering the disease are still unclear. Infections with certain viruses have been suggested as possible environmental triggers for the autoimmune process that leads to selective and progressive destruction of pancreatic β-cells and insufficiency of insulin production, which is its hallmark. In this review, advances in knowledge and evidence that suggest the participation of certain viruses in the mechanisms of disease initiation and progression are described. It has been accepted that environmental factors, including viruses, can initiate and possibly sustain, accelerate, or slow down the autoimmune process and consequently damage insulin-producing pancreatic β-cells. Although the role of these agents, especially human enteroviruses, has been exhaustively studied as the most likely triggers of the activation of autoimmunity that destroys pancreatic islets and leads to T1DM, certain doubts remain. Clinical epidemiological and experimental studies in humans and animals provide consistent and increasing evidence that persistent viral infections, especially with human enteroviruses and rotavirus infections, are associated with an increased risk of the disease in individuals genetically predisposed to autoimmunity.

Future in the past: paternal reprogramming of offspring phenotype and the epigenetic mechanisms.

That certain preconceptual paternal exposures reprogram the developmental phenotypic plasticity in future generation(s) has conceptualized the "paternal programming of offspring health" hypothesis. This transgenerational effect is transmitted primarily through sperm epigenetic mechanisms-DNA methylation, non-coding RNAs (ncRNAs) and associated RNA modifications, and histone modifications-and potentially through non-sperm-specific mechanisms-seminal plasma and circulating factors-that create 'imprinted' memory of ancestral information. The epigenetic landscape in sperm is highly responsive to environmental cues, due to, in part, the soma-to-germline communication mediated by epididymosomes. While human epidemiological studies and experimental animal studies have provided solid evidences in support of transgenerational epigenetic inheritance, how ancestral information is memorized as epigenetic codes for germline transmission is poorly understood. Particular elusive is what the downstream effector pathways that decode those epigenetic codes into persistent phenotypes. In this review, we discuss the paternal reprogramming of offspring phenotype and the possible underlying epigenetic mechanisms. Cracking these epigenetic mechanisms will lead to a better appreciation of "Paternal Origins of Health and Disease" and guide innovation of intervention algorithms to achieve 'healthier' outcomes in future generations. All this will revolutionize our understanding of human disease etiology.

A model for stimulation of enzyme activity by a competitive inhibitor based on the interaction of terazosin and phosphoglycerate kinase 1

The drug terazosin (TZ) binds to and can enhance the activity of the glycolytic enzyme phosphoglycerate kinase 1 (PGK1) and can increase ATP levels. That finding prompted studies of TZ in Parkinson's disease (PD) in which decreased neuronal energy metabolism is a hallmark feature. TZ was neuroprotective in cell-based and animal PD models and in large epidemiological studies of humans. However, how TZ might increase PGK1 activity has remained a perplexing question because structural data revealed that the site of TZ binding to PGK1 overlaps with the site of substrate binding, predicting that TZ would competitively inhibit activity. Functional data also indicate that TZ is a competitive inhibitor. To explore the paradoxical observation of a competitive inhibitor increasing enzyme activity under some conditions, we developed a mass action model of TZ and PGK1 interactions using published data on PGK1 kinetics and the effect of varying TZ concentrations. The model indicated that TZ-binding introduces a bypass pathway that accelerates product release. At low concentrations, TZ binding circumvents slow product release and increases the rate of enzymatic phosphotransfer. However, at high concentrations, TZ inhibits PGK1 activity. The model explains stimulation of enzyme activity by a competitive inhibitor and the biphasic dose-response relationship for TZ and PGK1 activity. By providing a plausible mechanism for interactions between TZ and PGK1, these findings may aid development of TZ or other agents as potential therapeutics for neurodegenerative diseases. The results may also have implications for agents that interact with the active site of other enzymes.

Animal Approaches to Studying Risk Factors for Parkinson's Disease: A Narrative Review.

Despite recent efforts to search for biomarkers for the pre-symptomatic diagnosis of Parkinson's disease (PD), the presence of risk factors, prodromal signs, and family history still support the classification of individuals at risk for this disease. Human epidemiological studies are useful in this search but fail to provide causality. The study of well-known risk factors for PD in animal models can help elucidate mechanisms related to the disease's etiology and contribute to future prevention or treatment approaches. This narrative review aims to discuss animal studies that investigated four of the main risk factors and/or prodromal signs related to PD: advanced age, male sex, sleep alterations, and depression. Different databases were used to search the studies, which were included based on their relevance to the topic. Although still in a reduced number, such studies are of great relevance in the search for evidence that leads to a possible early diagnosis and improvements in methods of prevention and treatment.

Pathologists’ perspective on the study design, analysis, and interpretation of proliferative lesions in a lifetime rodent carcinogenicity bioassay of sucralose

Sucralose, a sugar substitute first approved for use in 1991, is a non-caloric sweetener regulated globally as a food additive. Based on numerous experimental animal studies (dating to the 1980s) and human epidemiology studies, international health agencies have determined that sucralose is safe when consumed as intended. A single lifetime rodent carcinogenicity bioassay conducted by the Ramazzini Institute (RI) reported that mice fed diets containing sucralose develop hematopoietic neoplasia, but controversy continues regarding the validity and relevance of these data for predicting health effects in humans. The present paper addresses the controversy by providing the perspective of experienced pathologists on sucralose-related animal toxicity and carcinogenicity data generally, and the RI carcinogenicity bioassay findings specifically, using results from publicly available papers and international regulatory authority decisions. In the authors’ view, flaws in the design, methodology, data evaluation, and reporting of the RI carcinogenicity bioassay for sucralose diminish the value of the data as evidence that this agent represents a carcinogenic hazard to humans. This limitation will remain until the RI bioassay is repeated under Good Laboratory Practices and the design, data, and accuracy of the pathology diagnoses and interpretations reviewed by qualified pathologists with experience in evaluating potential chemically-induced carcinogenic hazards.

Endothelial Nitric Oxide synthase (eNOS) in Preeclampsia: An Update.

Preeclampsia (PE) is a common pregnancy-related hypertensive disorder and is a leading cause of maternal and perinatal morbidity and mortality. The incidence of PE and its associated health care costs have been increasing in the United States over the past three decades. Pregnancies complicated by PE put both the mother and child at increased risk for chronic illnesses such as cardiovascular disease, cerebrovascular disease, and cognitive impairment later in life. To date, there is no effective treatment for PE and the etiology of PE is largely unknown. While human epidemiological studies have established an association between various genetic factors and PE, a causative link between genes associated with PE and PE development has been difficult to establish. Human studies have shown that variants in eNOS (endothelial nitric oxide synthase, also known as NOS3) gene are associated with PE, and animal experimental studies have provided evidence to show the potential functional connection between the eNOS gene and PE. Here we review several studies that investigated the role of eNOS in PE, as well as studies that described how manipulating the eNOS/NO pathway could aid in disease intervention.

Maternal obesity and autism spectrum disorders in offspring

There is a growing body of evidence from both human epidemiologic and animal studies that maternal obesity and a high-fat diet are associated with autism spectrum disorders (ASDs). They also include cognitive impairment, attention deficit hyperactivity disorder, cerebral palsy, anxiety and depression, schizophrenia, and eating disorders. This review synthesizes the role of the maternal immune activation hypothesis and the other possible mechanism underlying abnormal fetal brain development, including neuroinflammation; increased oxidative stress, dysregulated insulin, glucose, and leptin signaling; dysregulated serotonergic and dopaminergic signaling; and perturbations in synaptic plasticity and neurodevelopmental and psychiatric morbidity in offspring. Finally, this review summarizes the available targeted strategies that can be designed to curb maternal obesity and the subsequent development of ASDs.

P1159 Gene and environment interactions in inflammatory bowel disease: a systematic review of human epidemiologic studies

Abstract Background Complex gene-environment interaction for Inflammatory Bowel Disease (IBD) remains elusive. This systematic review aims to summarize the current evidence of gene and environment interactions in IBD. Methods PubMed, EMBASE, Web of Science and Scopus were systematically searched from inception through July 20, 2022 to identify publications examining the interaction effect of genetic variants and environmental factors in IBD. Two investigators independently screened the title/abstract and full text according to the predefined criteria. All eligible studies were graded using STREGA guideline. The protocol was registered on PROSPERO (CRD42023443071). Results 4,305 publications were identified and screened, resulting in 36 eligible studies. 17 studies reported statistically significant interactions. The interaction effect of NOD2 and smoking was most frequently investigated and showed variant-specific interaction at rs2066847 regrading risk of Crohn’s disease (CD). Gene-smoking interactions were further identified in 1) other IBD risk genes (ATG16L1, IL23R, CALM3), as well as the IBD-genetic risk score (GRS), 2) detoxification genes (GSTP1 and ΗΜΟΧ1), 3) smoking-associated genes (CHRNA3, CHRNA5, PPP1R3C, BDNF), as well as the general smoking-GRS, and 4) the inflammation cytokine gene (IL-1β) using the candidate gene approach. Using the Illumina immune-focused Chip, another 64 smoking interacting variants were identified. Gene-diet interactions were reported across different nutritional measures, including the intake of fatty acids with CYP4F3 and FADS2, serum level of selenium with SEPHS1and SEPSECS, dietary intake of potassium with IL21, alcohol consumption with IL12B, dietary heme iron intake with FcgRIIA and serum level of 25-hydroxyvitamin D with VDR. No genome wide environment interaction studies (GWEIS) of IBD have been conducted to date, while this strategy holds great potential to unravel the missing heritability influenced by environment factors for IBD. Conclusion While past studies have increased insights into potential gene-environmental interactions in the pathophysiology of IBD, current evidence is limited and inconclusive due to lack of replication of presented results, and limited study power. Further research, including GWEIS and clinical trials, is needed for future recommendations on lifestyle and dietary modification, based on individual genetic backgrounds.

Distribution of parabens and 4-HB in human blood

Human blood has been commonly and routinely analyzed to determine internal human exposure to parabens. However, data on the occurrence of parabens and their common metabolite, p-hydroxybenzoic acid (4-HB), in different human blood matrixes is still limited. In this study, 139 pairs of serum and whole blood samples were collected from Chinese adults, and then analyzed them for 5 parabens and 4-HB. Methylparaben (MeP) and propylparaben (PrP) were consistently the predominant parabens in human serum (mean 2.3 and 2.1 ng/mL, respectively) and whole blood (1.9 and 1.3 ng/mL, respectively). Mean concentrations of 4-HB in human serum and whole blood were 7.7 and 12 ng/mL, respectively. Concentrations of parabens, except benzylparaben (BzP), and 4-HB in human serum were significantly (p < 0.01) correlated with that in whole blood. Distribution pattern of parabens and 4-HB in human blood was evaluated, for the first time, based on their partitioning between human serum and whole blood (Kp). Mean Kp values of parabens, except BzP, increased with the alkyl chain length from 0.83 to 1.6. BzP (mean 1.4) had a comparable mean Kp value to PrP (mean 1.4). Among target analytes, 4-HB had the lowest mean Kp value (0.75). These data are important to select appropriate blood matrixes for conducting human exposure assessment and epidemiological studies on parabens.

Closing the sex/gender gap in dementia: homing in on the vasculature (biomarkers)

AbstractAs we move toward precision medicine approaches, we cannot continue to pursue a one model fits all. Sex differences in brain aging and degeneration have been reported across the spectrum of research methodologies from human epidemiological studies and drug trials to model systems of degenerative brain disease. Blood proteomic biomarkers combined with clinical data can provide useful multi‐modal disease models in humans to uncover important biological associations with relevance to human disease. Small vessel disease in aging or AD is prevalent in the aging populations and represents a common and important risk factor for cognitive impairment. Dysregulated angiogenesis is emerging as a relevant pathology in SVD‐related vascular cognitive impairment with potential for therapeutic modulation. Recent work by our group and others is suggesting that the association of plasma markers of angiogenesis with clinical outcomes is sex dimorphic. Results demonstrate several age and sex‐dependent associations between groups of markers that capture both beneficial and pathological aspects of angiogenesis in aging. Much remains to be uncovered regarding underlying mechanisms, interactions with neurodegenerative pathologies, and ideal windows for sex‐informed therapeutic interventions on angiogenesis. However, the emerging body of work on sex differences regarding angiogenesis in aging, AD and other neurodegenerative disorders, represents a critical first step toward demonstrating the relevance of sex/gender to therapeutically oriented studies of vascular pathologies in dementia‐causing diseases.

Safety and Feasibility of a 16-Week Progressive Exercise Intervention in Treatment Naïve Chronic Lymphocytic Leukaemia

A growing body of evidence from preclinical and human epidemiology studies of multiple cancer types indicate that physical activity can delay or avert the outgrowth of cancer, in a mechanistic process that may involve exercise-induced alterations to anti-cancer immunity. Many Chronic Lymphocytic leukaemia (CLL) patients present with asymptomatic, early-stage disease that is monitored until disease progression. Thus, exercise may be an effective way to manage disease burden and delay progression in treatment naïve CLL. The primary objective of this pilot study was to investigate the safety and feasibility of an exercise programme in people with treatment naïve CLL, and preliminarily explore the effects of exercise training on CLL counts, body composition, cardiorespiratory fitness, and immune cell phenotypes including T-cells. We approached N = 100 treatment naïve CLL patients (Binet stage A and B) (Figure 1). Trial uptake was 40%, thus n = 40 participants with treatment naïve CLL were screened. After assessing suitability for exercise (e.g., resting electrocardiogram and other safety tests), n = 11 participants were excluded - the majority of these, n = 9, were due to the presence of cardiac abnormalities. Consequently, n = 28 participants were randomised into a 16-week, home-based, supervised, personalised, progressive exercise intervention ( n = 14: mean ± SD: age = 62 ± 12 years) or 16-weeks of usual care, control group ( n = 14: mean ± SD: age = 61 ± 10 years). The overall retention rate was 86%, with 79% of the exercise group and 93% of the control group completing the trial. Adherence to the exercise intervention was 92 ± 8%. One serious adverse event was reported (hospitalisation for pneumonia) that was unrelated to the trial and one adverse event was reported (syncope following exercise) that was related to the trial. Together, this evidence indicates that exercise training is both safe and feasible in people with treatment naïve CLL who passed pre-trial screening. The exercise intervention elicited a 2% increase in DEXA-derived lean mass in the exercise group compared to a 0.4% decrease in the control group ( p = .01) (Table 1). DEXA-derived total body fat percentage decreased by 4% and 1% and fat mass decreased by 3% and 2% ( p &amp;lt; .05) respectively in the exercise and control groups but there was no significant difference between the groups ( p &amp;gt; 0.05). Resting systolic and diastolic blood pressure was lower at post-intervention in both groups ( p &amp;lt; .05); the exercise group reduced systolic and diastolic blood pressure by 5% and 2% respectively and the control group reduced by 6% and 7% respectively, but there was no significant difference between groups ( p&amp;gt;0.05) suggesting the observed changes could be the result of “white coat hypertension” pre-intervention. Additionally, no changes were observed for whole-body mass, BMI, bone mineral density, resting heart rate, or measures of cardiorespiratory fitness (all p&amp;gt;0.05). This trial provided a unique opportunity to investigate the effects of regular exercise on neoplastic activity in humans (i.e., CLL counts) without the confounding presence of anti-cancer therapy. Resting blood samples collected pre- and post-intervention were analysed by flow cytometry to enumerate CD5 +CD19 + CLL cells clonally restricted to kappa or lambda. No differences were observed for clonal CLL cells over time or between conditions ( p&amp;gt;0.05) (Table 1). We also analysed resting blood samples collected pre- and post-intervention by flow cytometry to enumerate T cell subsets. No statistically significant changes were observed between conditions pre-intervention to post-intervention for CD4 + or CD8 + T-cell subsets including, naïve (CD27 +CD45RA +), stem cell-like memory (CD27 +CD45RA +CD127 +CD95 +), central memory (CD27 +CD45RA -), effector memory (CD27 -CD45RA -), EMRAs (CD27 -CD45RA +) or exhausted T-cells (PD1 +, Tim3 +) or FoxP3 T-regulatory cells (CD4 +CD127 lowCD25 +FoxP3 +) (all p&amp;gt;0.05). Our results show that exercise is safe and feasible in people with treatment naïve CLL who passed pre-trial screening. In addition, exercise training increased lean mass. No changes were observed to CLL cells. The latter finding is unsurprising given the poorly immunogenic profile of CLL.

Circadian dysfunction induces NAFLD-related human liver cancer in a mouse model

Chronic circadian dysfunction increases the risk of non-alcoholic fatty liver disease (NAFLD)-related hepatocellular carcinoma (HCC), but the underlying mechanisms and direct relevance to human HCC have not been established. In this study, we aimed to determine whether chronic circadian dysregulation can drive NAFLD-related carcinogenesis from human hepatocytes and human HCC progression. Chronic jet lag of mice with humanized livers induces spontaneous NAFLD-related HCCs from human hepatocytes. The clinical relevance of this model was analysed by biomarker, pathological/histological, genetic, RNA sequencing, metabolomic, and integrated bioinformatic analyses. Circadian dysfunction induces glucose intolerance, NAFLD-associated human HCCs, and human HCC metastasis independent of diet in a humanized mouse model. The deregulated transcriptomes in necrotic-inflammatory humanized livers and HCCs bear a striking resemblance to those of human non-alcoholic steatohepatitis (NASH), cirrhosis, and HCC. Stable circadian entrainment of hosts rhythmically paces NASH and HCC transcriptomes to decrease HCC incidence and prevent HCC metastasis. Circadian disruption directly reprogrammes NASH and HCC transcriptomes to drive a rapid progression from hepatocarcinogenesis to HCC metastasis. Human hepatocyte and tumour transcripts are clearly distinguishable from mouse transcripts in non-parenchymal cells and tumour stroma, and display dynamic changes in metabolism, inflammation, angiogenesis, and oncogenic signalling in NASH, progressing to hepatocyte malignant transformation and immunosuppressive tumour stroma in HCCs. Metabolomic analysis defines specific bile acids as prognostic biomarkers that change dynamically during hepatocarcinogenesis and in response to circadian disruption at all disease stages. Chronic circadian dysfunction is independently carcinogenic to human hepatocytes. Mice with humanized livers provide a powerful preclinical model for studying the impact of the necrotic-inflammatory liver environment and neuroendocrine circadian dysfunction on hepatocarcinogenesis and anti-HCC therapy. Human epidemiological studies have linked chronic circadian dysfunction to increased hepatocellular carcinoma (HCC) risk, but direct evidence that circadian dysfunction is a human carcinogen has not been established. Here we show that circadian dysfunction induces non-alcoholic steatohepatitis (NASH)-related carcinogenesis from human hepatocytes in a murine humanized liver model, following the same molecular and pathologic pathways observed in human patients. The gene expression signatures of humanized HCC transcriptomes from circadian-disrupted mice closely match those of human HCC with the poorest prognostic outcomes, while those from stably circadian entrained mice match those from human HCC with the best prognostic outcomes. Our studies establish a new model for defining the mechanism of NASH-related HCC and highlight the importance of circadian biology in HCC prevention and treatment.

Discussion. Has the human population become a sentinel for the adverse effects of PFAS contamination on wildlife health and endangered species?

Global contamination with per- and polyfluoroalkyl substances (PFAS) poses a threat to both human health and the environment, with significant implications for ecological conservation policies. A growing list of peer-reviewed publications indicates that PFAS can harm wildlife health and that the adverse effects associated with PFAS exposure in wildlife are in concordance with human epidemiological studies. The correlation of cross-species data supports a unique perspective that humans can be regarded as a sentinel for PFAS effects in other species. The health harms due to PFAS are potentially most concerning for populations of endangered and threatened species that are simultaneously exposed to PFAS and other toxic pollutants, and also face threats to their survival due to habitat loss, degradation of ecosystems, and over-harvesting. Human epidemiological studies on the PFAS doses associated with health harm present a rich source of information about potential impacts on wildlife health due to PFAS. Our analysis suggests that national and international efforts to restrict the discharges of PFAS into the environment and to clean up PFAS-contaminated sites present an opportunity to protect wildlife from chemical pollution and to advance species conservation worldwide.

A history of asthma may be associated with grandparents' exposures to stress and cigarette smoking.

Introduction: Within human epidemiological studies, associations have been demonstrated between grandparental exposures during childhood and grandchildren's outcomes. A few studies have assessed whether asthma has ancestral associations with exposure to cigarette smoking, but results have been mixed so far. Material and methods: In this study we used four generations: (F0 great-grandparents, F1 grandparents, F2 parents, F3 study children) of the Avon Longitudinal Study of Parents and Children (ALSPAC) to determine whether there is evidence of associations between asthma in generations F2 or F3 and exposures to severe trauma in childhood and/or active cigarette smoking during the adolescence of grandmothers and grandfathers in generations F0 and F1 respectively, or of a history of a F0 or F1 grandmother smoking during pregnancy. Results: We have shown that: a) stress exemplified by the death of a F1 grandparent's parent during the grandparents' childhood was associated with increased risk of asthma in generation F3, especially if the grandparent involved was the paternal grandmother; b) if the grandparents of generations F0 or F1 smoked during adolescence (i.e. < 17 years), their grandchildren in generations F2 and F3 were more likely to have a history of asthma; c) paternal F1 grandmother's smoking in pregnancy was associated with her F3 grandchild's asthma at age 7; d) There were differences between the results for the grandsons and granddaughters of the paternal grandmother with exposure to smoking in adolescence and with smoking in pregnancy. e) The addition of all of the individual exposure variables to the different analyses often provided a considerable increase in goodness of fit compared with only adding demographic factors associated with asthma at P < 0.10 such as social class; this was particularly true when all four exposure variables were combined in one model, suggesting possible synergistic effects between them. Discussion: We have shown associations between all four types of exposure to the grandparents to be associated with asthma in the grandchildren, such that the results both depended on whether the male or female line was involved, and the sex of the grandchildren. It was notable that the paternal grandmother was particularly involved in many of the associations. We emphasize that these are exploratory analyses, that asthma diagnostic criteria likely changed over time and may not be consistent between generations, and that the results should be tested in other cohorts.

Elevated arsenic level in fasting serum via ingestion of fish meat increased the risk of hypertension in humans and mice.

There has been a shortage of human studies to elucidate the association between serum arsenic levels and the prevalence of hypertension. This study multidirectionally investigated associations among arsenic exposure, dietary ingestion, and the risk of hypertension by combined human epidemiological and mouse experimental studies. This study focused on the total arsenic level in fasting serum, a biomarker of arsenic exposure. Associations among ingestion frequencies of 54 diet items of Japanese food separated into six categories, total arsenic level in fasting serum, and the prevalence of hypertension were investigated in 2709 general people in Japan. Logistic regression analysis demonstrated a dose-dependent association between serum arsenic level and hypertension and a positive association between the ingestion of fish meat and hypertension. Further analysis showed that the latter association was fully mediated by increased fasting serum arsenic levels in humans. Similarly, oral exposure to the putative human-equivalent dose of arsenic species mixture with the same ratios in a common fish meat in Japan increased systolic blood pressure and arsenic levels in fasting serum in mice. This interdisciplinary approach suggests that fish-meat ingestion is a potential risk factor for arsenic-mediated hypertension. Because the increased consumption of fish meat is a recent global trend, health risks of the increased ingestion of arsenic via fish meat should be further investigated.

Ether lipid biosynthesis promotes lifespan extension and enables diverse pro-longevity paradigms in Caenorhabditis elegans.

Biguanides, including the world's most prescribed drug for type 2 diabetes, metformin, not only lower blood sugar, but also promote longevity in preclinical models. Epidemiologic studies in humans parallel these findings, indicating favorable effects of metformin on longevity and on reducing the incidence and morbidity associated with aging-related diseases. Despite this promise, the full spectrum of molecular effectors responsible for these health benefits remains elusive. Through unbiased screening in Caenorhabditis elegans, we uncovered a role for genes necessary for ether lipid biosynthesis in the favorable effects of biguanides. We demonstrate that biguanides prompt lifespan extension by stimulating ether lipid biogenesis. Loss of the ether lipid biosynthetic machinery also mitigates lifespan extension attributable to dietary restriction, target of rapamycin (TOR) inhibition, and mitochondrial electron transport chain inhibition. A possible mechanistic explanation for this finding is that ether lipids are required for activation of longevity-promoting, metabolic stress defenses downstream of the conserved transcription factor skn-1/Nrf. In alignment with these findings, overexpression of a single, key, ether lipid biosynthetic enzyme, fard-1/FAR1, is sufficient to promote lifespan extension. These findings illuminate the ether lipid biosynthetic machinery as a novel therapeutic target to promote healthy aging.

Murine models of advanced maternal age: a systematic review and meta-analysis.

Animal models have been developed to aid understanding of the increased incidence of adverse pregnancy complications observed in women of advanced maternal age (AMA). This systematic review of murine models of AMA demonstrates consistent effects of decreased litter size and fetal weight; this supports the future use of these models to determine pathophysiological mechanisms and test therapeutic strategies to improve poor pregnancy outcomes in AMA. Advanced maternal age (AMA; ≥35 years of age) is associated with an increased risk of adverse pregnancy outcomes. To explore causes of adverse pregnancy outcomes in AMA, and to test candidate therapies, an increasing number of murine AMA models have been developed. The aim of this study was to systematically review the literature to assess whether murine AMA models demonstrate a reproducible effect on pregnancy outcomes. PubMed, Ovid, Web of Science and Google Scholar were searched. Studies that reported on pregnancy outcomes in AMA mice and rats were included; the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) tool evaluated the risk of bias. Eleven mouse and six rat studies were included. AMA mice and rats had reduced litter size (standardised mean difference (SMD): -1.59, 95% confidence interval (CI): -1.84, -1.34 for mice; SMD: -1.66, 95% (CI): -2.09, -1.23 for rats) and reduced fetal weight (SMD: -0.87, 95% CI: -1.24, -0.49 for mice; SMD: -1.05, 95% CI: -1.40, -0.69 for rats). Placental weight was increased in AMA mice (SMD: 0.62, 95% CI: 0.16, 1.08). Subgroup analysis indicated that C57Bl/6 mice had less heterogeneity than other, mostly outbred, mouse strains with regards to litter size (C57 strain I2 = 68.2% vs other strain types I2 = 85.7%). The risk of bias was high, mostly due to the lack of methodological detail and unclear reporting of findings. Murine models of AMA demonstrate similar adverse pregnancy outcomes to those observed in large human epidemiological studies. The reproducible phenotypes in AMA murine models allow the exploration of mechanisms underpinning poor pregnancy outcomes and the pursuit of therapeutic interventions.

Nine human epidemiological studies on synthetic amorphous silica and respiratory health

The respiratory health effects of Synthetic Amorphous Silica (SAS) have been studied in human epidemiological research. This article presents a historical overview and review of nine occupational worker studies that have been conducted so far on this topic. The combined study population of all of these studies included 1172 employees, and exposure concentrations ranged from < 1 mg/m3 to 100 mg/m3. In two studies with a total of 293 workers, the incidence of silicosis was investigated after long-term exposure to precipitated SAS, and no cases of silicosis were found (Plunkett and Dewitt, 1962; Volk, 1960). In another study, the spirometry results of 40 workers were normal (Vitums et al., 1977). In a study of 28 workers, 4 cases of silicosis were identified, but it is possible that contamination with cristobalite occurred and detailed information about the amorphous silica origin was not provided (Mohrmann and Kahn, 1985). Ferch et al. (1987) found that lung impairment was associated with confounding factors (smoking) but not with exposure to precipitated SAS in a study of 143 workers. Choudat et al. (1990) reported a reduction in forced expiratory flow in a group exposed to precipitated SAS compared to a control group. Still, they found no correlation between the extent of exposure and pulmonary function was found in a study of 131 workers. Wilson et al. (1979) also failed to show a significant association between the degree of exposure to precipitated SAS and annual changes in lung function in a study of 165 workers. In the most recent and most extensive study (Taeger et al., 2016; Yong et al., 2022) in Germany, involving 462 factory workers, no association between inhalable or respirable SAS dust exposure and respiratory health was reported. Based on the available data, there is no evidence-base to support a relationship between SAS and respiratory health in humans.

Of Men and Mice: Using Terrestrial Radiation Epidemiology Methods to Inform Analysis of Animal Models for Space Radiation Risk Assessment.

Prediction of cancer risk from space radiation exposure is critical to ensure spaceflight crewmembers are adequately informed of the risks they face when accepting assignments to ambitious long-duration exploratory missions. Although epidemiological studies have assessed the effects of exposure to terrestrial radiation, no robust epidemiological studies of humans exposed to space radiation exist to support estimates of the risk from space radiation exposure. Mouse data derived from recent irradiation experiments provides valuable information to successfully develop mouse-based excess risks models for assessing relative biological effectiveness for heavy ions that can provide information to scale unique space radiation exposures so that excess risks estimated for terrestrial radiation can be adjusted for space radiation risk assessment. Bayesian analyses were used to simulate linear slopes for excess risk models with several different effect modifiers for attained age and sex. Relative biological effectiveness values for all-solid cancer mortality were calculated from the ratio of the heavy-ion linear slope to the gamma linear slope using the full posterior distribution and resulted in values that were substantially lower than what is currently applied in risk assessment. These analyses provide an opportunity to improve characterization of parameters used in the current NASA Space Cancer Risk (NSCR) model and generate new hypotheses for future animal experiments using out-bred mouse populations.