Circulating Interleukin-1-Beta Levels after Acute and Prolonged Exposure to Low Temperatures: Human and Rat Studies

Abstract

In this study we have investigated whether IL-1 acts as a mediator of stress responses elicited by exposure to low temperatures. We also sought whether IL-1 is released from the adrenal gland under basal conditions or after exposure to low temperatures. Normal and adrenalectomized (ADX) rats were used for acute studies, whereas the effects of a prolonged exposure were investigated in a group of human subjects during a 45-day stay in Antarctica. Circulating levels of interleukin-1β (IL-1β) were taken as a marker of systemic IL-1 production both in humans and rats. In the latter, serum corticosterone (Cort) was also estimated. In intact rats, exposure to low temperatures (–25 or –35°C) for 30 or 90 min did not modify circulating IL-1β levels with respect to controls taken at +20°C. Adrenalectomy was associated with an increase in cytokine levels only in the group exposed to –35°C for 90 min; such increase is statistically significant compared to all groups of normal rats, whatever the experimental condition, as well as to ADX rats exposed to +20°C and –25°C for 30 and 90 min. In normal rats, the increase in circulating Cort levels was already maximal after exposure to –25°C for 30 min. In humans, circulating IL-1β levels after 45 days in Antarctica were significantly lower than those measured on arrival in the same subjects. Thus, no change in circulating IL-1β was associated with acute low-temperature stress in rats, whereas a marked decrease in serum cytokine was observed in humans after prolonged exposure to a cold environment. Experiments with ADX rats indicated that the contribution of the adrenal glands to total-body IL-1β production is negligible or absent.

Wintering in Antarctica: Impact on Immune Response of Indian Expeditioners

“…Shearer et al [2] (2002) reported increased proinflammatory cytokines in winter expeditioners, which is in agreement with our study. In contrast to our findings, an Italian study showed a marked decrease in serum cytokine levels in human subjects after prolonged exposure to a cold environment [9] . Shirai et al [3] have reported that exposure to an Antarctic winter induced a dramatic decrease in the levels of TNF-␣ , IL-1Ra, IL-6 and IL-1 ␤ in serum samples.…”

“…A typical monocytosis was detected and a striking reduction in the proinflammatory cytokine was noted [7]. Decreased serum levels of IL-10, IL-6, IL-1 receptor antagonist [8] and IL-1β were detected [9]. It has been recognized that cold stress affects various aspects of both cellular and humoral immunity in experimental animals: it decreases lymphocyte proliferation, natural killer cell count and cytolytic activity; it activates complement and induces heatshock proteins [10,11,12].…”

Circulating HHIP Levels in Women with Insulin Resistance and PCOS: Effects of Physical Activity, Cold Stimulation and Anti-Diabetic Drug Therapy

“…It has reported that cold exposure stimulates the sympathetic nervous system (SNS) to promote BAT activation, which in turn affects glucose and lipid metabolism [32]. In fact, previous studies have found that under conditions of physiological stress, such as cold exposure, the in vivo cytokine levels (IL-1ß) increase [33]. The reason for the increase in cytokine levels in response to stress is not clear, but it may be caused by an increase in the levels of stress hormones such as adrenaline.…”

“…The free androgen index (FAI) was calculated as FAI = [testosterone (TEST)/sex-hormone binding globulin (SHBG)] × 100 [32]. Body adiposity index (BAI) was calculated as BAI = hip circumference/height 1.5 − 18 [33]. Visceral adiposity index (VAI) = waist circumference (WC)/(36.58 + 1.89 ×BMI) × tri-glyceride (TG)/0.81 × 1.52/high-density lipoprotein cholesterol (HDL-C) [34].…”