GNB3, eNOS, and mitochondrial DNA polymorphisms correlate to natural longevity in a Xinjiang Uygur population

Sex differences in alpha-synucleinopathies: a systematic review

Background

Past research indicates a higher prevalence, incidence, and severe clinical manifestations of alpha-synucleinopathies in men, leading to a suggestion of neuroprotective properties of female sex hormones (especially estrogen). The potential pathomechanisms of any such effect on alpha-synucleinopathies, however, are far from understood. With that aim, we undertook to systematically review, and to critically assess, contemporary evidence on sex and gender differences in alpha-synucleinopathies using a bench-to-bedside approach.

Methods

In this systematic review, studies investigating sex and gender differences in alpha-synucleinopathies (Rapid Eye Movement (REM) Behavior Disorder (RBD), Parkinson's Disease (PD), Dementia with Lewy Bodies (DLB), Multiple System Atrophy (MSA)) from 2012 to 2022 were identified using electronic database searches of PubMed, Embase and Ovid.

Results

One hundred sixty-two studies were included; 5 RBD, 6 MSA, 20 DLB and 131 PD studies. Overall, there is conclusive evidence to suggest sex-and gender-specific manifestation in demographics, biomarkers, genetics, clinical features, interventions, and quality of life in alpha-synucleinopathies. Only limited data exists on the effects of distinct sex hormones, with majority of studies concentrating on estrogen and its speculated neuroprotective effects.

Conclusion

Future studies disentangling the underlying sex-specific mechanisms of alpha-synucleinopathies are urgently needed in order to enable novel sex-specific therapeutics.

Association of m.5178C>A variant with serum lipid levels: a systematic review and meta-analysis

Background: Emerging evidence shows that m.5178C>A variant is associated with a lower risk of coronary artery disease (CAD). However, the specific mechanisms remain elusive. Since dyslipidemia is one of the most critical risk factors for CAD and accounts for at least 50% of the population-attributable risk, it is tempting to speculate that the reduced CAD risk caused by the m.5178C>A variant may stem from an improved lipid profile. In order to verify this hypothesis, we conducted the present study to clarify the association of m.5178C>A variant with lipid levels.

Methods: By searching ten databases for studies published before 30 June 2021. Thirteen East Asian populations (7587 individuals) were included for the analysis.

Results: The present study showed that m.5178C>A variant was associated with higher high-density lipoprotein cholesterol (HDL-C) [standardized mean difference (SMD) = 0.12, 95% confidence interval (CI) = 0.06–0.17, P<0.001] and total cholesterol (TC) (SMD = 0.08, 95% CI = 0.02–0.14, P=0.01) levels. In subgroup analysis, the association of m.5178C>A variant with higher HDL-C levels were observed in Japanese (SMD = 0.09, 95% CI = 0.01–0.17, P=0.03) and Chinese populations (SMD = 0.13, 95% CI = 0.07–0.20, P<0.001). However, the association of m.5178C>A variant with lower low-density lipoprotein cholesterol (LDL-C) levels were only observed in Japanese populations (SMD = −0.11, 95% CI = −0.22 to 0.00, P=0.04).

Conclusions: The m.5178C>A variant was associated with higher HDL-C and lower LDL-C levels in Japanese populations, which may contribute to decreased CAD risk and longevity of Japanese.

GSTT1, GSTP1 and XPC genes are associated with longevity in an Italian cohort

Longevity is a complex process controlled by environmental and genetic factors. We evaluated the association of seven drug metabolising and DNA-repair gene polymorphisms with longevity in an Italian cohort. A sample of 756 subjects aged 18-98 was genotyped for CYP1A1 (rs1048943, A>G), GSTM1 (rs 1183423000, presence/absence), GSTT1 (rs1601993659, presence/absence), GSTP1 (rs1695, A>G), XRCC1 (rs1799782, C>T), XRCC1 (rs25489, A>G) and XPC (rs2228001, A>C) gene polymorphisms. The association between the studied gene polymorphisms and longevity was evaluated by dividing the sample into three age groups: 18-50, 51-85, and 86-98. We observed a significant decrease in the frequency of the GSTT1 null, GSTP1 G and XPC C alleles in the oldest group with respect to the youngest one. We also obtained the same results when dividing the sample into 18-85 and 86-98 age groups. The general linear model analyses confirmed a significant decreasing trend with age of the above mentioned alleles. We hypothesised that these minor alleles, being important in the sensitivity against the development of different types of cancer, may reflect a reduced life-expectancy in carrier subjects and may explain their significantly lower frequency observed among subjects belonging to the oldest age group.

Genetic background, epigenetic factors and dietary interventions which influence human longevity

Longevity is mainly conditioned by genetic, epigenetic and environmental factors. Different genetic modifications seem to be positively associated to longevity, including SNPs in SIRT1, APOE, FOXO3A, ACE, ATM, NOS1 and NOS2 gene. Epigenetic changes as DNA hyper- and hypo-methylation influence significantly human longevity by activating/deactivating different genes involved in physiological mechanisms. Several studies have confirmed that centenarians have a lower DNA methylation content compared to young subjects, which showed more homogeneously methylated DNA region. Also the up-regulation of miR-21 seems to be more associated with longevity in different populations of long-lived subjects, suggesting its role as potential epigenetic biomarkers. A non-pharmacological treatment that seems to contrast age-related diseases and promote longevity is represented by dietary intervention. It has been evaluated the effects of dietary restriction of both single nutrients or total calories to extend lifespan. However, in daily practice it is very difficult to guarantee adherence/compliance of the subjects to dietary restriction and at the same time avoid dangerous nutritional deficiencies. As consequence, the attention has focused on a variety of substances both drugs and natural compounds able to mime the beneficial effects of caloric restriction, including resveratrol, quercetin, rapamycin, metformin and 2-deoxy-D-glucose.

Ancestry and different rates of suicide and homicide in European countries: A study with population-level data

INTRODUCTION

There are large differences in suicide rates across Europe. The current study investigated the relationship of suicide and homicide rates in different countries of Europe with ancestry as it is defined with the haplotype frequencies of Y-DNA and mtDNA.

MATERIAL AND METHODS

The mortality data were retrieved from the WHO online database. The genetic data were retrieved from http://www.eupedia.com. The statistical analysis included Forward Stepwise Multiple Linear Regression analysis and Pearson Correlation Coefficient (R).

RESULTS

In males, N and R1a Y-DNA haplotypes were positively related to both homicidal and suicidal behaviors while I1 was negatively related. The Q was positively related to the homicidal rate. Overall, 60-75% of the observed variance was explained. L, J and X mtDNA haplogroups were negatively related with suicide in females alone, with 82-85% of the observed variance described.

DISCUSSION

The current study should not be considered as a study of genetic markers but rather a study of human ancestry. Its results could mean that research on suicidality has a strong biological but locally restricted component and could be limited by the study population; generalizability of the results at an international level might not be possible. Further research with patient-level data are needed to verify whether these haplotypes could serve as biological markers to identify persons at risk to commit suicide or homicide and whether biologically-determined ancestry could serve as an intermediate grouping method or even as an endophenotype in suicide research.

Association between mitochondrial DNA variations and schizophrenia in the northern Chinese Han population

To determine whether mitochondrial DNA (mtDNA) variations are associated with schizophrenia, 313 patients with schizophrenia and 326 unaffected participants of the northern Chinese Han population were included in a prospective study. Single-nucleotide polymorphisms (SNPs) including C5178A, A10398G, G13708A, and C13928G were analyzed by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). Hypervariable regions I and II (HVSI and HVSII) were analyzed by sequencing. The results showed that the 4 SNPs and 11 haplotypes, composed of the 4 SNPs, did not differ significantly between patient and control groups. No significant association between haplogroups and the risk of schizophrenia was ascertained after Bonferroni correction. Drawing a conclusion, there was no evidence of an association between mtDNA (the 4 SNPs and the control region) and schizophrenia in the northern Chinese Han population.

Characterization of mitochondrial DNA polymorphisms in the Han population in Liaoning Province, Northeast China

This study characterized the genetic variations of mitochondrial DNA (mtDNA) to elucidate the maternal genetic structure of Liaoning Han Chinese. A total of 317 blood samples of unrelated individuals were collected for analysis in Liaoning Province. The mtDNA samples were analyzed using two distinct methods: sequencing of the hypervariable sequences I and II (HVSI and HVSII), and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the coding region. The results indicated a high gene diversity value (0.9997 ± 0.0003), a high polymorphism information content (0.99668) and a random match probability (0.00332). These samples were classified into 305 haplotypes, with 9 shared haplotypes. The most common haplogroup was D4 (12.93%). The principal component analysis map, the phylogenetic tree map, and the genetic distance matrix all indicated that the genetic distance of the Liaoning Han population from the Tibetan group was distant, whereas that from the Miao group was relatively close.

A mitochondrial haplogroup is associated with decreased longevity in a historic new world population

Interest in mitochondrial influences on extended longevity has been mounting, as evidenced by a growing literature. Such work has demonstrated that some haplogroups are associated with increased longevity and that such associations are population specific. Most previous work, however, suffers from the methodological shortcoming that long-lived individuals are compared with "controls" who are born decades after the aged individuals. The only true controls of the elderly are people who were born in the same time period but who did not have extended longevity. Here we present results of a study in which we are able to test whether longevity is independent of haplogroup type, controlling for time period, by using mtDNA genealogies. Since mtDNA does not recombine, we know the mtDNA haplogroup of the maternal ancestors of our living participants. Thus, we can compare the haplogroup of people with and without extended longevity who were born during the same time period. Our sample is an admixed New World population that has haplogroups of Amerindian, European, and African origin. We show that women who belong to Amerindian, European, and African haplogroups do not differ in their mean longevity. Therefore, to the extent that ethnicity was tied in this population to mtDNA make-up, such ethnicity did not impact longevity. In support of previous suggestions that the link between mtDNA haplogroups and longevity is specific to the population being studied, we found an association between haplogroup C and decreased longevity. Interestingly, the lifetime reproductive success and the number of grandchildren produced via a daughter of women with haplogroup C are not reduced. Our diachronic approach to the mtDNA and longevity link allowed us to determine that the same haplogroup is associated with decreased longevity during different time periods and allowed us to compare the haplogroup of short- and long-lived individuals born during the same time period. By controlling for time period, we minimized the effect of different cultural and ecological environments on differential longevity. With our diachronic approach, we investigated the mtDNA and longevity link with a biocultural perspective.

Association of the mt-ND2 5178A/C polymorphism with Parkinson's disease

Mitochondria play an important role in the etiology of Parkinson's disease (PD). While mutations in the mitochondrial DNA (mtDNA) have been shown to accumulate in PD, no specific mtDNA polymorphisms have been associated with susceptibility or resistance to PD. A cytosine to adenine transversion at base pair 5178 in the mtDNA has been associated with increased longevity and resistance against a number of age related disorders and has been shown to decrease mitochondrial reactive oxygen species (ROS) production. We sought to determine whether 5178A is associated with resistance against PD in a Han Chinese population. To assess its association with PD, we genotyped 484 idiopathic PD patients and 710 control individuals for 5178C/A. Genotyping was performed using restriction fragment length polymorphism (RFLP) analysis. There was no significant association between 5178A and PD (P=0.308) when analyzing the entire population. However, sub-group analysis revealed that in males the frequency of 5178A was significantly lower in PD patients (27.7% in controls vs 20.0% in PD patients, P=0.027). Stratification of the population by age showed that this trend held across age groups but only reached statistical significance in males aged 60-70 (29.1% in controls vs 14.05 in PD patients, P=0.011). In conclusion, we demonstrated that the frequency of 5178A was significantly decreased in male PD patients in a Han Chinese population. This polymorphism may be associated with resistance against the development of PD when in combination with loci on the Y chromosome.

Genetic factors associated with longevity: a review of recent findings

Given the rising rate of survival into advanced old age in the United States, achieving longevity and healthy aging is becoming increasingly important. Besides maintaining healthy lifestyle behaviors, positive aging outcomes may also be heritable, with estimates ranging from 20% to 35%. In this qualitative review, we summarize recent findings on genetic factors linked to longevity across different populations and study designs. Recent studies not only confirm the association of APOE with longevity in different populations, but also implicate several other pathways that may influence longevity including nitric oxide production, inflammation, immunity, and DNA damage response and repair. Recent evidence also suggests that mitochondrial DNA may play an important role in attaining longevity. Despite these implicated pathways, longevity may be a polygenic trait influenced by a complex interplay of multiple genes. Future genetic studies on aging would benefit from larger samples of long-lived individuals, birth-cohort matched controls, inclusion of different aging phenotypes (e.g., aging free of morbidities), and analysis of gender differences.