Basal body temperature as a biomarker of healthy aging

Cold exposure protects against medial arterial calcification development via autophagy

Medial arterial calcification (MAC), a systemic vascular disease different from atherosclerosis, is associated with an increased incidence of cardiovascular events. Several studies have demonstrated that ambient temperature is one of the most important factors affecting cardiovascular events. However, there has been limited research on the effect of different ambient temperatures on MAC. In the present study, we showed that cold temperature exposure (CT) in mice slowed down the formation of vitamin D (VD)-induced vascular calcification compared with room temperature exposure (RT). To investigate the mechanism involved, we isolated plasma-derived exosomes from mice subjected to CT or RT for 30 days (CT-Exo or RT-Exo, respectively). Compared with RT-Exo, CT-Exo remarkably alleviated the calcification/senescence formation of vascular smooth muscle cells (VSMCs) and promoted autophagy by activating the phosphorylation of AMP-activated protein kinase (p-AMPK) and inhibiting phosphorylation of mammalian target of rapamycin (p-mTOR). At the same time, CT-Exo promoted autophagy in β-glycerophosphate (β-GP)-induced VSMCs. The number of autophagosomes and the expression of autophagy-related proteins ATG5 and LC3B increased, while the expression of p62 decreased. Based on a microRNA chip microarray assay and real-time polymerase chain reaction, miR-320a-3p was highly enriched in CT-Exo as well as thoracic aortic vessels in CT mice. miR-320a-3p downregulation in CT-Exo using AntagomiR-320a-3p inhibited autophagy and blunted its anti-calcification protective effect on VSMCs. Moreover, we identified that programmed cell death 4 (PDCD4) is a target of miR-320a-3p, and silencing PDCD4 increased autophagy and decreased calcification in VSMCs. Treatment with CT-Exo alleviated the formation of MAC in VD-treated mice, while these effects were partially reversed by GW4869. Furthermore, the anti-arterial calcification protective effects of CT-Exo were largely abolished by AntagomiR-320a-3p in VD-induced mice. In summary, we have highlighted that prolonged cold may be a good way to reduce the incidence of MAC. Specifically, miR-320a-3p from CT-Exo could protect against the initiation and progression of MAC via the AMPK/mTOR autophagy pathway.

Distribution of the follicular and luteal phase lengths and their age-dependent changes in Japanese women: A large population study

Purpose

The current definition of menstrual cycle length in a Japanese woman is different from those of WHO definition, and the original data are outdated. We aimed to calculate the distribution of follicular and luteal phases length in modern Japanese women with various menstrual cycles.

Methods

This study determined the lengths of the follicular and luteal phases of Japanese women using basal body temperature data collected via a smartphone application from 2015 to 2019, and the data were analyzed using the Sensiplan method. Over 9 million temperature readings from more than 80 000 participants were analyzed.

Results

The mean duration of the low-temperature (follicular) phase averaged 17.1 days and was shorter among participants aged 40-49 years. The mean duration of the high-temperature (luteal) phase was 11.8 days. The variance and maximum-minimum difference of the length of the low temperature period were significant in women under 35 years old than women aged more than 35 years.

Conclusions

The shortening of the follicular phase in women aged 40-49 years implied a relationship with the rapid decline of ovarian reserve in these women, and the age 35 years old was turning point of ovulatory function.

Clinical outcomes of geriatric patients with COVID-19: review of one-year data

Aims

In this study, we aimed to reveal mortality rates and factors affecting survival in geriatric patients infected with COVID-19.

Methods

This is a retrospective study of 873 geriatric patients with COVID-19 who were hospitalized between March 11, 2020 and March 11, 2021. Demographic, clinical, laboratory data, and treatment options were obtained from electronic medical records. Multivariate logistic regression was used to explore the risk factors for in-hospital death.

Results

During the specified period, 643 patients were discharged, and 230 patients died in the hospital. The mean age was 75.08 ± 7.39 years (mean ± SD) and 51.8% were males. We found that older age (≥ 85), polypharmacy, dyspnea, abnormal thorax computed tomography (CT), lower doses of anticoagulation, and high values of white blood cell, aspartate aminotransferase, C-reactive protein, lactate dehydrogenase, ferritin were associated with a significant increase in mortality (P < 0.001 for all). Although all of these values were significant in multivariate logistic regression analysis, the most important ones were dyspnea (Odds ratio (OR) 57.916, 95% confidence interval (CI) 23.439–143.104, P < 0.001), polypharmacy (OR 6.782, 95% CI 3.082–14.927, P < 0.001), and thorax CT classification (typical; OR 9.633, 95% CI 2.511–37.122, P < 0.001).

Conclusion

Older age, polypharmacy, dyspnea, and abnormal thorax CT were the most significant mortality criteria and in addition appropriate anticoagulant use was associated with reduced mortality. Identifying the risk factors to predict mortality in older adults with COVID-19 is important to treat future cases successfully.

Body Temperature Is Associated With Cognitive Performance in Older Adults With and Without Mild Cognitive Impairment: A Cross-sectional Analysis

Wearable devices for remote and continuous health monitoring in older populations frequently include sensors for body temperature measurements (i.e., skin and core body temperatures). Healthy aging is associated with core body temperatures that are in the lower range of age-related normal values (36.3 ± 0.6°C, oral temperature), while patients with Alzheimer's disease (AD) exhibit core body temperatures above normal values (up to 0.2°C). However, the relation of body temperature measures with neurocognitive health in older adults remains unknown. This study aimed to explore the association of body temperature with cognitive performance in older adults with and without mild cognitive impairment (MCI). Eighty community-dwelling older adults (≥65 years) participated, of which 54 participants were cognitively healthy and 26 participants met the criteria for MCI. Skin temperatures at the rib cage and the scapula were measured in the laboratory (single-point measurement) and neuropsychological tests were conducted to assess general cognitive performance, episodic memory, verbal fluency, executive function, and processing speed. In a subgroup (n = 15, nine healthy, six MCI), skin and core body temperatures were measured continuously during 12 h of habitual daily activities (long-term measurement). Spearman's partial correlation analyses, controlled for age, revealed that lower median body temperature and higher peak-to-peak body temperature amplitude was associated with better general cognitive performance and with better performance in specific domains of cognition; [e.g., rib median skin temperature (single-point) vs. processing speed: rs = 0.33, p = 0.002; rib median skin temperature (long-term) vs. executive function: rs = 0.56, p = 0.023; and peak-to-peak core body temperature amplitude (long-term) vs. episodic memory: rs = 0.51, p = 0.032]. Additionally, cognitively healthy older adults showed lower median body temperature and higher peak-to-peak body temperature amplitude compared to older adults with MCI (e.g., rib median skin temperature, single-point: p = 0.035, r = 0.20). We conclude that both skin and core body temperature measures are potential early biomarkers of cognitive decline and preclinical symptoms of MCI/AD. It may therefore be promising to integrate body temperature measures into multi-parameter systems for the remote and continuous monitoring of neurocognitive health in older adults.

Cell non-autonomous regulation of health and longevity

As the demographics of the modern world skew older, understanding and mitigating the effects of aging is increasingly important within biomedical research. Recent studies in model organisms demonstrate that the aging process is frequently modified by an organism’s ability to perceive and respond to changes in its environment. Many well-studied pathways that influence aging involve sensory cells, frequently neurons, that signal to peripheral tissues and promote survival during the presence of stress. Importantly, this activation of stress response pathways is often sufficient to improve health and longevity even in the absence of stress. Here, we review the current landscape of research highlighting the importance of cell non-autonomous signaling in modulating aging from C. elegans to mammals. We also discuss emerging concepts including retrograde signaling, approaches to mapping these networks, and development of potential therapeutics.

Age-Dependent and Seasonal Changes in Menstrual Cycle Length and Body Temperature Based on Big Data

Our smartphone application–based analysis of 6 million menstrual cycles among Japanese females found age-dependent and seasonal changes of cycle length and basal body temperature.

OBJECTIVE:

To evaluate the effects of age and season on menstrual cycle length and basal body temperature (BBT). We also examined the effects of climate on cycle length and BBT, taking into account Japanese geographic and social characteristics.

METHODS:

In this retrospective cohort study, we analyzed data from 6 million menstrual cycles entered into a smartphone application from 310,000 females from 2016 to 2017. Only those who entered more than 10 cycles in 2 years were included. Generalized estimation equations were used to adjust for confounding factors and for within-person correlations of multiple records. Multiple regression analysis was conducted, with age, external average temperature, precipitation amount, and sunshine hours as confounding factors.

RESULTS:

The mean menstrual cycle length increased from age 15–23 years, subsequently decreased up to age 45 years, and then increased again. Average follicular phase body temperature showed no significant age-dependent changes, but luteal phase body temperature gradually increased up to 29 years and then stabilized and started to decrease after age 42 years. A significant association between external temperature and body temperature (follicular and luteal phase) was observed, though menstrual cycle length did not show such an association.

CONCLUSION:

These results, derived from data self-entered into a smartphone application, revealed underrecognized age-dependent and seasonal changes in menstrual cycle length and BBT, which will contribute to a better understanding of female reproductive health in the modern world.

Regulatory systems that mediate the effects of temperature on the lifespan of Caenorhabditis elegans

Temperature affects animal physiology, including aging and lifespan. How temperature and biological systems interact to influence aging and lifespan has been investigated using model organisms, including the nematode Caenorhabditis elegans. In this review, we discuss mechanisms by which diverse cellular factors modulate the effects of ambient temperatures on aging and lifespan in C. elegans. C. elegans thermosensory neurons alleviate lifespan-shortening effects of high temperatures via sterol endocrine signaling and probably through systemic regulation of cytosolic proteostasis. At low temperatures, C. elegans displays a long lifespan by upregulating the cold-sensing TRPA channel, lipid homeostasis, germline-mediated prostaglandin signaling, and autophagy. In addition, co-chaperone p23 amplifies lifespan changes affected by high and low temperatures. Our review summarizes how external temperatures modulate C. elegans lifespan and provides information regarding responses of biological processes to temperature changes, which may affect health and aging at an organism level.

Risk factors for predicting mortality in elderly patients with COVID-19: A review of clinical data in China

While elderly patients are at high risk of fatality, research concerning COVID-19 has largely been done on clarifying the clinical features. As such, the present work aims to identify risk factors for mortality in elderly patients with COVID-19. Given that single-centre studies are less likely informative as elderly remains a minority in the total Chinese population, the present study reviewed the clinical data of geriatric COVID-19 patients gathered from different sources in the public domain. Based on the data of 154 individuals from 26 provinces, age remained a key mortality risk factor among geriatric patients of different ages. While dyspnoea and chest pain/discomfort were more commonly seen in deceased patients as they represented severe pneumonia, fever was more prominent in surviving patients. This was likely due to the lower baseline body temperature observed in elderly which translated to a lower maximum temperature of fever. However, lowering the threshold temperature for fever is not recommended in surveillance. Instead, baseline body temperature measured on a regular basis should be used to define the threshold temperature for fever. Against mixed results, more research should be done on identifying comorbidities associated with mortality in geriatric patients.

Blood-brain barrier and innate immunity in the pathogenesis of Alzheimer's disease

The pathogenesis of Alzheimer's disease (AD) is only partly understood. This is the probable reason why significant efforts to treat or prevent AD have been unsuccessful. In fact, as of April 2019, there have been 2094 studies registered for AD on the clinicaltrials.gov U.S. National Library of Science web page, of which only a few are still ongoing. In AD, abnormal accumulation of amyloid and tau proteins in the brain are thought to begin 10-20 years before the onset of overt symptoms, suggesting that interventions designed to prevent pathological amyloid and tau accumulation may be more effective than attempting to reverse a pathology once it is established. However, to be successful, such early interventions need to be selectively administered to individuals who will likely develop the disease long before the symptoms occur. Therefore, it is critical to identify early biomarkers that are strongly predictive of AD. Currently, patients are diagnosed on the basis of a variety of clinical scales, neuropsychological tests, imaging and laboratory modalities, but definitive diagnosis can be made only by postmortem assessment of underlying neuropathology. People suffering from AD thus may be misdiagnosed clinically with other primary causes of dementia, and vice versa, thereby also reducing the power of clinical trials. The amyloid cascade hypothesis fits well for the familial cases of AD with known mutations, but is not sufficient to explain sporadic, late-onset AD (LOAD) that accounts for over 95% of all cases. Since the earliest descriptions of AD there have been neuropathological features described other than amyloid plaques (AP) and neurofibrillary tangles (NFT), most notably gliosis and neuroinflammation. However, it is only recently that genetic and experimental studies have implicated microglial dysfunction as a causal factor for AD, as opposed to a merely biological response of its accumulation around AP. Additionally, many studies have suggested the importance of changes in blood-brain barrier (BBB) permeability in the pathogenesis of AD. Here we suggest how these less investigated aspects of the disease that have gained increased attention in recent years may contribute mechanistically to the development of lesions and symptoms of AD.