Changes in Total Cholesterol and Heart Rate in Normotensive and Hypertensive Rats under Combined Influence of Cold Exposure and Hypokinesia

Pathological mechanisms of cold and mechanical stress in modulating cancer progression

Environmental temperature and cellular mechanical force are the inherent factors that participate in various biological processes and regulate cancer progress, which have been hot topics worldwide. They occupy a dominant part in the cancer tissues through different approaches. However, extensive investigation regarding pathological mechanisms in the carcinogenic field. After research, we found cold stress via two means to manipulate tumors: neuroscience and mechanically sensitive ion channels (MICHs) such as TRP families to regulate the physiological and pathological activities. Excessive cold stimulation mediated neuroscience acting on every cancer stage through the hypothalamus-pituitary-adrenocorticoid (HPA) to reach the target organs. Comparatively speaking, mechanical force via Piezo of MICHs controls cancer development. The progression of cancer depends on the internal activation of proto-oncogenes and the external tumorigenic factors; the above two means eventually lead to genetic disorders at the molecular level. This review summarizes the interaction of bidirectional communication between them and the tumor. It covers the main processes from cytoplasm to nucleus related to metastasis cascade and tumor immune escape.

Indicators of LPO and Antioxidant Protection in Rats During Long-Term Restriction of Motor Activity

This article presents a comprehensive study of the parameters of LPO (concentrations of malondialdehyde, diene conjugates, and intensity of chemiluminescence) and antioxidant defense (concentrations of α-tocopherol, ceruloplasmin, total antioxidant activity, antiradical activity, and activities of antioxidant enzymes - superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) in blood plasma and erythrocytes of white male rats during restriction of motor activity up to 28 days. The patterns of changes in oxidative balance in hypokinesia in the form of intensification of LPO processes against the background of depletion of resources of antioxidant defense with maximum manifestation on days 14-21 of the experiment were revealed.

Temperature variability increases the onset risk of ischemic stroke: A 10-year study in Tianjin, China

Background

Epidemiological evidence suggests a correlation between ambient temperature and ischemic stroke. However, evidence on the impact of daily temperature variability on the onset of ischemic stroke is lacking and limited.

Objective

We aimed to investigate the short-term association between temperature variability and ischemic stroke occurrence in Tianjin.

Methods

We performed a 10-year analysis of ischemic stroke patients hospitalized in two affiliated hospitals of Tianjin Medical University from 2011 to 2020. Daily meteorological data were collected from the Tianjin Meteorological Bureau. Temperature variability was calculated from the standard deviation (SD) of daily minimum and maximum temperatures over exposure days. A quasi-Poisson generalized linear regression combined with distributed lag non-linear model (DLNM) was used to estimate the effect of temperature variability on daily stroke onset, while controlling for daily mean temperature, relative humidity, long-term trend and seasonality, public holiday, and day of the week.

Results

Temperature variability was positively associated with ischemic stroke. A 1°C increase in temperature variability at 0-1 days (TV_0-1) was associated with a 4.1% (1.9-6.3%) increase of ischemic stroke onset. In a stratified analysis, men, people aged ≤65 years, and individuals with pre-existing hypertension, hyperlipidemia, hyperhomocysteinemia were more susceptible to temperature variability. Furthermore, the influence pattern of temperature variability on ischemic stroke was different in the cold season (November-April) and the warm season (May-October).

Conclusion

Our findings suggested that short-term temperature variability exposure could increase the risk of ischemic stroke, which may provide new insights into the impact of climate change on health.

The underlying mechanisms of cold exposure-induced ischemic stroke

Growing evidence suggests that cold exposure is to some extent a potential risk factor for ischemic stroke. At present, although the mechanism by which cold exposure induces ischemic stroke is not fully understood, some potential mechanisms have been mentioned. First, the seasonal and temperature variability of cerebrovascular risk factors (hypertension, hyperglycemia, hyperlipidemia, atrial fibrillation) may be involved. Moreover, the activation of sympathetic nervous system and renin-angiotensin system and their downstream signaling pathways (pro-inflammatory AngII, activated platelets, and dysfunctional immune cells) are also major contributors. Finally, the influenza epidemics induced by cold weather are also influencing factors that cannot be ignored. This article is the first to systematically and comprehensively describe the underlying mechanism of cold-induced ischemic stroke, aiming to provide more preventive measures and medication guidance for stroke-susceptible individuals in cold season, and also provide support for the formulation of public health policies.

Effect of Sex on Structural and Morphological Parameters of Rat Heart under Conditions of Combined Exposure to Hypokinesia and Cold

We studied the combined effect of hypokinesia and external cooling on structural and morphological changes in the ventricular myocardium and parameters of homeostasis of the blood system in male and female WKY (normotensive) and SHR (hypertensive) rats. Simultaneous exposure to hypokinesia and cold caused destructive processes in the myocardium and high dynamics of heart remodeling with diverse structural and morphological changes in the left ventricle in rats of both sexes. The thickness of the left ventricular wall most rapidly decreased in male hypertensive SHR rats. The thickness of the wall of the right ventricle significantly increased in male and female rats of both strains. In WKY and SHR females, structural transformations in the heart were less pronounced than in males. The key role in different degree of morphological remodeling of the myocardium in male and female probably belongs to sex hormones.