Journal of Physiological Anthropology最新文献

Humans have long pondered their genesis. The answer to the great question of where Homo sapiens come from has evolved in conjunction with biotechnologies that have allowed us to more brightly illuminate our distant past. The "Multiregional Evolution" model was once the hegemonic theory of Homo sapiens origins, but in the last 30 years, it has been supplanted by the "Out of Africa" model. Here, we review the major findings that have resulted in this paradigmatic shift. These include hominin brain expansion, classical insight from the mitochondrial genome (mtDNA) regarding the timing of the divergence point between Africans and non-Africans, and next-generation sequencing (NGS) of the Neanderthal and Denisovan genomes. These findings largely bolstered the "Out of Africa" model, although they also revealed a small degree of introgression of the Neanderthal and Denisovan genomes into those of non-African Homo sapiens. We also review paleogenomic studies for which migration route, north or south, early migrants to East Eurasia most likely traversed. Whichever route was taken, the migrants moved to higher latitudes, which necessitated adaptation for lower light conditions, colder clines, and pro-adipogenic mechanisms to counteract food scarcity. Further genetic and epigenetic investigations of these physiological adaptations constitute an integral aspect of the story of human origins and human migration to East Asia.

Background: Skin ageing is influenced by complex genetic factors. Various phenotypes such as wrinkling, pigmentation changes, and skin cancers have been linked to specific genetic loci. However, the underlying genetic mechanisms and pathways remain poorly understood. This systematic review and meta-analysis aims to summarise the genetic loci found to be associated with skin ageing phenotypes by published genome-wide association studies (GWAS) and candidate gene studies. We also evaluated the overall association of loci via meta-analysis and identified the association patterns to explore potential biological pathways contributing to skin ageing. The Web of Science, Embase, and PubMed databases were searched on January 2024 using specific exclusion criteria (e.g., study of non-human subjects, focus on skin diseases, or treatments) to identify relevant articles. There did not appear to be any significant publication bias observed across the all phenotypes.

Main body: A total of 48 studies were included, revealing 30 loci that were confirmed to be associated with skin ageing by multiple studies (e.g., AFG3L1P: odds ratio 1.133 95% confidence interval [1.044, 1.222]; BPIFA3: 1.859 [1.567, 2.151]; CLPTML1: 1.164 [1.0.99, 1.229]; CPNE7: 0.905 [0.852-0.958]; DEF8: 1.186 [1.042, 1.331]; IRF4: 1.260 [1.025, 1.495]; MYO16: 2.303 [1.697, 2.908]; PRDM16: 1.105 [1.084, 1.127]; RORA: 1.391 [1.206, 1.577]; SPG7: 0.922 [0.897, 0.947]; SPON1: 2.214 [1.204, 3.225]; SPTLC1: 1.464 [1.432, 1.495]; TYR: 1.175 [1.007, 1.343]). The lack of significance for many loci may be due to studies analysing different SNPs within the same locus, weakening the overall associations. Several loci were associated with specific phenotypic categories (e.g., skin colour related, skin cancer related, wrinkling and sagging related), suggesting shared biological pathways are involved in the pathogenesis of different skin ageing phenotypes. This pattern was also observed in several of the loci that do not have a significant overall association with skin ageing.

Conclusion: Despite significant heterogeneity among the included studies and the use of subjective visual methods for phenotype assessment, our review highlights the critical role of fundamental biological processes, such as development and cellular organisation, in skin ageing. Future research that targets the same SNP across multiple populations could strengthen the association of additional loci with skin ageing. Further investigation into these underlying biological processes would significantly advance our understanding of the pathogenesis of skin ageing phenotypes.

Background: Skin ageing takes on many different forms. Despite this diversity in skin ageing phenotypes, literature published to date is limited in scope, as many research studies either focus on one single phenotype or just a few specific phenotypes. Presently, phenotypes such as wrinkles, pigment spots, and photo-ageing are receiving most of the research attention. We therefore wonder whether the current discourse on skin ageing places a disproportionate amount of focus on a few selected phenotypes, leaving other skin ageing phenotypes underexplored.

Methods: In this cross-sectional study, we performed a broad assessment of forty-one signs of skin ageing and characterised the phenotypes that constituted key components of skin ageing. We also explored the interrelationship among forty-one skin ageing phenotypes using Spearman's Correlation and Principal Component Analysis.

Results: We analysed our study population, which is composed of 3281 ethnic Chinese participants from the Singapore/Malaysia Cross-sectional Genetics Epidemiology Study (SMCGES). The first ten principal components cumulatively explain 46.88% of the variance of skin ageing phenotypes in our study population. We discovered that the commonly discussed forms of skin ageing (i.e., wrinkles, pigmentation, and photo-ageing) only accounted for a small portion (24.39%) of the variance of all skin ageing phenotypes in our study population. Telangiectasia, a poor lip fullness, a lighter skin colour, xerosis, ephelides (freckles), ptosis of eyelids (droopy eyelids), eyebags, and a low eyebrow positioning were other key components of skin ageing, accounting for a further 22.49% of the variance of skin ageing phenotypes in our study population. We found that each of these ten skin ageing phenotypes characterises a key and important aspect of skin ageing. In this broad assessment of skin ageing, we first described the prevalence of forty-one signs of skin ageing and then characterised in detail both the prevalence and severity distribution of ten key skin ageing phenotypes.

Conclusions: We presented clear evidence that skin ageing is much more than just wrinkles, pigmentation and photo-ageing. The addition of telangiectasia, poor lip fullness, a lighter skin colour, xerosis, ephelides, ptosis of eyelids, eyebags, and a low eyebrow positioning added more dimensions to skin ageing phenotype presentations.

Background: The oxidative handicap hypothesis posits that testosterone-dependent traits, such as muscle mass and strength, may be costly to develop due to testosterone's pro-oxidative properties, leading to increased oxidative stress. This hypothesis suggests that only individuals with superior biological conditions can afford these costs. This study examines the oxidative handicap hypothesis, exploring the relationship between muscle mass or handgrip strength and oxidative stress markers in men.

Methods: Handgrip strength and muscle mass were measured in 179 men, with muscle mass assessed using bioelectrical impedance analysis (BIA) and handgrip strength measured using a hydraulic dynamometer. Serum testosterone levels and antioxidant capacity were measured. 8-OH-dG, 8-epi-PGF2α, and protein carbonyls were measured to evaluate oxidative stress level. Pearson's correlation and multivariate regression analyses were performed to examine the relationships between handgrip strength, muscle mass, and oxidative stress markers, controlling for age, serum testosterone levels, and antioxidant capacity.

Results: No significant correlations were found between handgrip strength and oxidative stress markers, even when controlling for muscle mass, antioxidant capacity, testosterone levels, and age.

Conclusions: The study's findings do not support the oxidative handicap hypothesis in the context of muscle parameters in men. The results suggest that testosterone-driven traits like handgrip strength or muscle mass may not necessarily incur oxidative stress costs in healthy young men, possibly due to effective compensatory antioxidant mechanisms. Factors like lifestyle, diet, and genetic predisposition, which were not controlled in this study, could also influence the observed outcomes and should be included in future research.

Background: Napping during night shifts is a countermeasure against fatigue and sleepiness, which both impact patient safety. However, there is insufficient evidence on how nurses nap, especially concerning their napping quality. This study explored night-shift napping and its associated factors among nurses, considering napping quantity and quality, to mitigate fatigue and sleepiness.

Methods: This month-long prospective observational study included 32 nurses working 16-h night shifts in a general ward. All nurses responded to questions on individual factors, while fatigue and sleepiness were checked four times during night shifts. Night-shift napping was measured using a wearable device and classified into six groups: time in bed [TIB] > 180 min and sleep efficiency [SE] ≥ 70%, TIB > 180 min and SE < 70%, TIB 120-180 min and SE ≥ 70%, TIB 120-180 min and SE < 70%, TIB < 120 min and SE ≥ 70%, and TIB < 120 min and SE < 70%.

Results: Most nurses (81.2%) worked four night shifts per month, and 105 night shifts in which nurses intended to nap were analyzed. The two nap conditions (TIB 120-180 min and SE ≥ 70%, TIB > 180 min and SE ≥ 70%) were not worse than other nap conditions in fatigue and sleepiness at the end of the night shift and change in fatigue from the start to the end of the night shift. Sleep reactivity, pre-nap time on electronic devices, and prophylactic naps taken before the night shift were each the common factors related to napping for TIB ≥ 120 min and SE ≥ 70%.

Conclusions: Nurses working long night shifts should consider both sufficient napping quantity and good napping quality. We suggest aiming for a TIB of at least 120 min and a SE of at least 70% to mitigate fatigue and sleepiness at the end of a night shift. Assessing sleep reactivity, pre-nap time on electronic devices, and prophylactic naps may be useful in achieving both quantity and quality effectively. Nurses and their managers should have a better understanding of napping and consider strategically taking naps during night shifts.

Background: Muscle architecture is closely related to muscle function. Increased knowledge of growth changes in muscle architecture will provide insights into the development of human movements and sports performance during the growth period. However, it is unclear how the muscle architecture of the medial gastrocnemius (MG) grows. This study examined the effects of growth on the muscle architecture of MG.

Methods: The brightness-mode ultrasonography technique was used to measure the muscle thickness, pennation angle, and fascicle length of MG in 146 Japanese boys aged to 6.2 - 17.9 years. The relative muscle thickness was calculated by dividing the absolute muscle thickness by body mass^1/3. The years from the age at peak height velocity were estimated for each participant, and used as the maturity index. A simple regression analysis was performed for the two variables in the full age range, as well as separately for the 5 - 12 years and 12 - 19 years subgroups. RESULTS AND CONCLUSION: The maturity index and chronological age were positively correlated with the relative muscle thickness, pennation angle, and fascicle length of MG. Subgroup analyses showed that chronological age was significantly correlated with the pennation angle, fascicle length, and absolute muscle thickness, except for the pennation angle of the 5 - 12 years subgroup. The present results indicate that muscle hypertrophy and elongation of fascicle length occur with growth. Our findings also suggest that the growth changes in pennation angle of MG differ between pre-adolescence and adolescence.

Background: Circulating fatty acid-binding protein 4 (FABP4) influences cardiovascular disease and glucose metabolism. Acute aerobic exercise increases circulating FABP4 concentrations, but the factors underlying this effect in humans are unclear. We investigated the effect of exercise duration on circulating FABP4 concentrations in healthy men.

Methods: This randomized crossover study enrolled healthy young men randomly assigned to two trials, short-duration (SE) and long-duration (LE) aerobic exercises trials. Both involved acute aerobic exercise followed by 60 min of bed rest. The exercise intensity was the same (40% peak oxygen uptake); however, the duration was 40 and 70 min for the SE and LE trials, respectively. Venous blood samples were collected to measure hormones, metabolites, and FABP4 concentrations.

Results: Twelve healthy young men completed both trials. Changes in hormone levels did not differ significantly between the SE and LE trials (p > 0.05). However, the circulating FABP4 concentration increased significantly only in the LE trial immediately after exercise (p = 0.018). It increased significantly 30-60 min post-exercise in both the SE and LE trials (p < 0.018), with the extent of the increase being significantly higher in the LE trial than in the SE trial (p < 0.001). In each trial, the total incremental area under the curve of circulating FABP4 concentration was significantly positively correlated with body fat percentage (SE trial: r_s = 0.699, p = 0.019; LE trial: r_s = 0.643, p = 0.024).

Conclusion: Our findings suggest that exercise duration is associated with the magnitude of increased FABP4 secretion into the blood circulation. Body fat accumulation may also be involved in the magnitude of FABP4 secretion induced by acute aerobic exercise.

Trial registration: The study was pre-registered with the University Hospital Medical Information Network Center (UMIN), a clinical trial registration system (ID: UMIN000051068).

The purpose of this study was to investigate the effects of elevated core temperature by exposure to heat stress vs. heat exposure without elevated core temperature (mean skin temperature only) in addition to mental fatigue on aerobic exercise capacity in the heat. Seven highly trained athletes completed two experimental conditions: elevation in core and skin temperatures (hyperthermia: HYP), and skin temperatures (SKIN). Participants performed the AX-Continuous Performance Task and Stroop Task to induce mental fatigue during a warm water immersion at 40 °C (HYP) and a passive seated heat exposure in a climatic chamber at 35 °C and 60% relative humidity (SKIN) for 45 min before exercise. Thereafter, participants performed running trial at 80% maximal oxygen uptake until voluntary exhaustion in the same chamber as the SKIN. Exercise time to exhaustion was significantly shorter in the HYP trial (538 ± 200 s) than in the SKIN trial (757 ± 324 s). Rectal temperature at the end of tasks in the HYP trial increased by 0.86 ± 0.26℃ and was significantly higher (37.69 ± 0.18℃) than that of the SKIN trial (36.96 ± 0.13℃), albeit no significant differences in mean skin temperature. Self-reported mental fatigue using visual analog scale was significantly higher after tasks in both trials, but no significant difference between trials was found. Throughout the trial, salivary cortisol concentration and perceptual responses were not affected by hyperthermia. This study demonstrated that a combination of high core temperature and mean skin temperature, and mental fatigue limit aerobic exercise capacity in highly trained athletes in hot environments compared with heat exposure without an elevation of core temperature.

Pentosidine is representative of the cross-linked structure of advanced glycation end products (AGEs) and has been suggested as a biomarker to assess bone and muscle quality. As studies on pentosidine in young adult men remain limited, we aimed to clarify the associations of urinary pentosidine with musculoskeletal status and physical performance in young men. Participants in this study comprised 32 men (age range: 19-39 years). Anthropometric measurements (body composition by InBody 430; stiffness index by ultrasound), muscle performance (grip strength by dynamometer, thigh muscle thickness by ultrasound), physical performance (functional reach test, 30-s chair stand test, and timed up and go test), and urinary biomarkers (pentosidine, N-telopeptide of type I collagen, and creatinine) were measured. In partial correlation analysis adjusted for age and height, higher urinary pentosidine levels were significantly associated with lower fat-free mass index (rho = - 0.368, p = 0.046), grip strength (rho = - 0.433, p = 0.017), rectus femoris thickness (rho = - 0.393, p = 0.032), and anterior thigh thickness (rho = - 0.416, p = 0.022), and a marginally inverse correlation was noted between urinary pentosidine levels and functional reach test (rho = - 0.327, p = 0.078). Our findings suggest that pentosidine correlates inversely with a few muscle and physical performance indicators. Pending future validations, urinary pentosidine may be a biomarker of AGEs in young men.