Intermittent Cold Research Articles

Activating thermogenesis to combat obesity: hot topic or cold front?

Activating thermogenesis to combat obesity: hot topic or cold front?

Intermittent cold exposure improves glucose homeostasis despite exacerbating diet‐induced obesity in mice housed at thermoneutrality

Ambient cold exposure is often regarded as a promising anti-obesity treatment in mice. However, most preclinical studies aimed at treating obesity via cold-induced thermogenesis have been confounded by subthermoneutral housing temperatures. Therefore, the ability of ambient cold to combat diet-induced obesity in mice housed under humanized thermoneutral conditions is currently unknown. Moreover, mammals such as mice are rarely exposed to chronic ambient cold without reprieve, yet mice are often subjected to experimental conditions of chronic rather than intermittent cold exposure (ICE), despite ICE being more physiologically relevant. In the present study, we provide novel evidence that thermoneutral housing uncouples the effects of ICE on glucose and energy homeostasis suggesting that ICE, despite improving glucose tolerance, is not an effective obesity treatment when mice are housed under humanized thermoneutral conditions. The present study examines whether a physiologically relevant model of ambient cold exposure, intermittent cold exposure (ICE), could ameliorate the metabolic impairments of diet-induced obesity in male and female mice housed under humanized thermoneutral conditions. Male and female C57BL/6J mice housed at thermoneutrality (29°C) were fed a low-fat diet or high-fat diet for 6weeks before being weight matched into groups that remained unperturbed or underwent ICE for 4 weeks (4°C for 60minday-1 ; 5daysweek-1 ) when being maintained on their respective diets. ICE induced rapid and persistent hyperphagia exacerbating rather than attenuating high-fat diet-induced obesity over time. These ICE-induced increases in adiposity were found to be energy intake-dependent via pair-feeding. Despite exacerbating high-fat diet-induced obesity, ICE improved glucose tolerance, independent of diet, in a sex-specific manner. The effects of ICE on glucose tolerance were not attributed to improvements in whole-body insulin tolerance, tissue specific insulin action, nor differences in markers of hepatic insulin clearance or pancreatic beta cell proliferation. Instead, ICE increased serum concentrations of insulin and C-peptide in response to glucose, suggesting that ICE may improve glucose tolerance by potentiating pancreatic glucose-stimulated insulin secretion. These data suggest that ICE, despite improving glucose tolerance, is not an effective obesity treatment in mice housed under humanized conditions.

Physiological Effects of Intermittent Passive Exposure to Hypobaric Hypoxia and Cold in Rats.

The benefits of intermittent hypobaric hypoxia (IHH) exposure for health and its potential use as a training tool are well-documented. However, since hypobaric hypoxia and cold are environmental factors always strongly associated in the biosphere, additive or synergistic adaptations could have evolved in animals’ genomes. For that reason, the aim of the present study was to investigate body composition and hematological and muscle morphofunctional responses to simultaneous intermittent exposure to hypoxia and cold. Adult male rats were randomly divided into four groups: (1) control, maintained in normoxia at 25°C (CTRL); (2) IHH exposed 4 h/day at 4,500 m (HYPO); (3) intermittent cold exposed 4 h/day at 4°C (COLD); and (4) simultaneously cold and hypoxia exposed (COHY). At the end of 9 and 21 days of exposure, blood was withdrawn and gastrocnemius (GAS) and tibialis anterior muscles, perigonadal and brown adipose tissue, diaphragm, and heart were excised. GAS transversal sections were stained for myofibrillar ATPase and succinate dehydrogenase for fiber typing and for endothelial ATPase to assess capillarization. Hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), and glucose transporter 1 (GLUT1) from GAS samples were semi-quantified by Western blotting. COLD and HYPO underwent physiological adjustments such as higher brown adipose tissue weight and increase in blood-related oxygen transport parameters, while avoiding some negative effects of chronic exposure to cold and hypoxia, such as body weight and muscle mass loss. COHY presented an additive erythropoietic response and was prevented from right ventricle hypertrophy. Intermittent cold exposure induced muscle angiogenesis, and IHH seems to indicate better muscle oxygenation through fiber area reduction.

Intermittent cold and hypobaric hypoxia treatment modulates oxidative stress in injured muscles of rats

Intermittent cold and hypobaric hypoxia treatment modulates oxidative stress in injured muscles of rats

Mirabegron: The most promising adipose tissue beiging agent.

Accumulation of white adipose tissue (WAT) underlies the obesity epidemic, leading to current therapeutic techniques that are being investigated for their ability to activate/“beige” this tissue. Adipose tissue (AT) beiging has been reported through intermittent cold exposure (CE), exercise, and β3‐Adrenergic Receptor (β3AR) agonists. But how AT beiging can help in the treatment of metabolic disorders like obesity and type 2 diabetes (T2D) remains largely unexplored. This review summarizes recent research on the use of β3AR agonist, mirabegron (Myrbetriq®), in stimulating beiging in AT. Researchers have only recently been able to determine the optimal therapeutic dose of mirabegron for inducing beiging in subcutaneous/ inguinal WAT, where the benefits of AT activation are evident without the undesired cardiovascular side effects. To determine whether the effects that mirabegron elicits are metabolically beneficial, a comparison of the undisputed findings resulting from intermittent CE‐induced beiging and the disputed findings from exercise‐induced beiging was conducted. Given the recent in vivo animal and clinical studies, the understanding of how mirabegron can be metabolically beneficial for both lean and obese individuals is more clearly understood. These studies have demonstrated that circulating adipokines, glucose metabolism, and lipid droplet (LD) size are all positively affected by mirabegron administration. Recent studies have also demonstrated that mirabegron has similar outcomes to intermittent CE and displays more direct evidence for beiging than those produced with exercise. With these current findings, mirabegron is considered the most promising and safest β3AR agonist currently available that has the potential to be used in the therapeutic treatment of metabolic disorders, and future studies into its interaction with different conditions may prove to be useful as part of a treatment plan in combination with a healthy diet and exercise.

Use of Gloves to Examine Intermittent Palm Cooling's Impact on Rowing Ergometry.

O'Brien, IT, Kozerski, AE, Gray, WD, Chen, L, Vargas, LJ, McEnroe, CB, Vanhoover, AC, King, KM, Pantalos, GM, and Caruso, JF. Use of gloves to examine intermittent palm cooling's impact on rowing ergometry. J Strength Cond Res 35(4): 931-940, 2021-The aim of this study was to examine the use of gloves on intermittent palm cooling's impact on rowing ergometry workouts. Our methods had subjects (n = 34) complete 3 rowing ergometer workouts of up to 8 2-minute stages separated by 45- or 60-second rests. They were randomized to one of the following treatments per workout: no palm cooling (NoPC), intermittent palm cooling as they rowed (PCex), or intermittent palm cooling as they rowed and post-exercise (PCex&post). Palm cooling entailed intermittent cold (initial temperature: 8.1° C) application and totaled 10 (PCex) and 20 (PCex&post) minutes, respectively. Workouts began with 8 minutes of rest after which pre-exercise data were obtained, followed by a ten-minute warm-up and the workout, and 20 minutes of post-exercise recovery. Numerous physiological and performance variables were collected before, during, and after workouts, and each was analyzed with either a two- or three-way analysis of variance. Our results include, with a 0.05 alpha and a simple effects post hoc, the distance rowed analysis produced a significant workout effect with PCex, PCex&post > NoPC. There were also significant interworkout differences for heart rate (HR) (NoPC > PCex) and blood lactate concentration (NoPC > PCex, PCex&post). We conclude that lower HRs and blood lactate concentrations from intermittent cooling caused subjects to experience less fatigue during those workouts and enabled more work to be performed. Continued research should identify optimal cooling characteristics to expedite body heat removal. Practical applications suggest that intermittent palm cooling administered with gloves enhance performance by abating physiological markers of fatigue.

Impact of an intermittent and localized cooling intervention on skin temperature, sleep quality and energy expenditure in free-living, young, healthy adults

Where people live and work together it is not always possible to modify the ambient temperature; ways must therefore be found that allow individuals to feel thermally comfortable in such settings. The Embr Wave® is a wrist-worn device marketed as a 'personal thermostat' that can apply a local cooling stimulus to the skin. The aim of the present study was to determine the effect of an intermittent mild cold stimulus of 25°C for 15-20s every 5min over 3.5 days under free-living conditions on 1) skin temperature, 2) perception of skin temperature, 3) sleep quality and 4) resting energy expenditure (REE) in young, healthy adults. Ten subjects wore the device for 3.5 consecutive days. This intervention reduced distal skin temperature after correcting for personal ambient temperature (P<0.05), but did not affect the subjects' the perception of skin temperature, sleep quality or REE (all P≥0.051). Thus, this intermittent mild cold regime can reduce distal skin temperature, and wearing it under free-living conditions for 3.5 days does not seem to impair the perception of skin temperature and sleep quality or modify REE.

Pharmacology and Mechanism of Action of HSK16149, a Selective Ligand of α2δ Subunit of Voltage-Gated Calcium Channel with Analgesic Activity in Animal Models of Chronic Pain.

Chronic pain is a public health problem because current treatments are unsatisfactory with small therapeutic index. Although pregabalin is effective for treating chronic pain, the clinical use is limited because of its side effects. Therefore, improving its therapeutic index is essential. In this study, HSK16149 was found to be a novel ligand of voltage-gated calcium channel (VGCC) α 2 δ subunit. HSK16149 inhibited [3H]gabapentin binding to the α 2 δ subunit and was 23 times more potent than pregabalin. In two rat models of neuropathic pain, the minimum effective dose (MED) of HSK16149 was 10 mg/kg, and the efficacy was similar to that of 30 mg/kg pregabalin. Moreover, the efficacy of HSK16149 could persist up to 24 hours postadministration at 30 mg/kg, whereas the efficacy of pregabalin lasted only for 12 hours at 30 mg/kg in streptozotocin-induced diabetic neuropathy model, indicating that HSK16149 might be a longer-acting drug candidate. HSK16149 could also inhibit mechanical allodynia in intermittent cold stress model and decrease phase II pain behaviors in formalin-induced nociception model. In addition, the locomotor activity test showed that the MED of HSK16149 was similar to that of pregabalin, whereas in the Rotarod test, the MEDs of HSK16149 and pregabalin were 100 and 30 mg/kg, respectively. These findings indicated that HSK16149 might have a better safety profile on the central nervous system. In summary, HSK16149 is a potent ligand of VGCC α 2 δ subunit with a better therapeutic index than pregabalin. Hence, it could be an effective and safe drug candidate for treating chronic pain. SIGNIFICANCE STATEMENT: As a novel potent ligand of voltage-gated calcium channel α 2 δ subunit, HSK16149 has the potential to be an effective and safe drug candidate for the treatment of chronic pain.

Implication of gut microbiota in the physiology of rats intermittently exposed to cold and hypobaric hypoxia.

This study examines the influence of intermittent exposure to cold, hypobaric hypoxia, and their combination, in gut microbiota and their metabolites in vivo, and explores their effects on the physiology of the host. Sprague-Dawley rats were exposed to cold (4°C), hypobaric hypoxia (462 torr), or both simultaneously, 4 h/day for 21 days. Biometrical and hematological parameters were monitored. Gut bacterial subgroups were evaluated by qPCR and short-chain fatty acids were determined by gas chromatography in caecum and feces. Cold increased brown adipose tissue, Clostridiales subpopulation and the concentration of butyric and isovaleric acids in caecum. Hypobaric hypoxia increased hemoglobin, red and white cell counts and Enterobacteriales, and reduced body and adipose tissues weights and Lactobacilliales. Cold plus hypobaric hypoxia counteracted the hypoxia-induced weight loss as well as the increase in white blood cells, while reducing the Bacteroidetes:Firmicutes ratio and normalizing the populations of Enterobacteriales and Lactobacilliales. In conclusion, intermittent cold and hypobaric hypoxia exposures by themselves modified some of the main physiological variables in vivo, while their combination kept the rats nearer to their basal status. The reduction of the Bacteroidetes:Firmicutes ratio and balanced populations of Enterobacteriales and Lactobacilliales in the gut may contribute to this effect.

Optogenetically-induced long term depression in the rat orbitofrontal cortex ameliorates stress-induced reversal learning impairment

Cognitive flexibility is a higher-order executive function that requires plasticity in neuronal circuits of the prefrontal cortex. Deficits in cognitive flexibility are prominent in a variety of psychiatric disorders, such as major depression, obsessive-compulsive disorder, and posttraumatic stress disorder. Chronic stress induces deficits in cognitive flexibility, perhaps through effects on plasticity, but the mechanism is not well understood. Previous work has demonstrated that stress reduces activity and dendritic elaboration in the medial prefrontal cortex (mPFC). In contrast, stress appears to increase dendritic elaboration in the orbitofrontal cortex (OFC). This suggests that there may be a differential effect of stress on plasticity in different prefrontal cortical areas. To test this hypothesis, we examined the effects of inducing plasticity optogenetically in the OFC on reversal learning, an OFC-mediated form of cognitive flexibility, in stressed and non-stressed rats. Inducing opto-LTD in the projection from mediodorsal thalamus to OFC ameliorated reversal learning deficits in rats exposed to chronic intermittent cold (CIC) stress. Additionally, we found that inducing opto-LTP in non-stressed rats produced deficits in reversal learning similar to those seen in rats after CIC stress. Finally, CIC stress produced complex subregion-specific changes in dendritic material and spine subtype composition in the OFC. These results indicate that the effects of stress on plasticity in the OFC are distinct from those in the mPFC, and that the PFC should therefore not be treated as a homogenous region in studying either stress effects or potential treatments for stress-related psychiatric disorders.

Mirtazapine, an α2 Antagonist-Type Antidepressant, Reverses Pain and Lack of Morphine Analgesia in Fibromyalgia-Like Mouse Models.

Treatment of fibromyalgia is an unmet medical need; however, its pathogenesis is still poorly understood. In a series of studies, we have demonstrated that some pharmacological treatments reverse generalized chronic pain but do not affect the lack of morphine analgesia in the intermittent cold stress (ICS)-induced fibromyalgia-like pain model in mice. Here we report that repeated intraperitoneal treatments with mirtazapine, which is presumed to disinhibit 5-hydroxytriptamine (5-HT) release and activate 5-HT1 receptor through mechanisms of blocking presynaptic adrenergic α2 and postsynaptic 5-HT2 and 5-HT3 receptors, completely reversed the chronic pain for more than 4 to 5 days after the cessation of treatments. The repeated mirtazapine treatments also recovered the morphine analgesia after the return of nociceptive threshold to the normal level. The microinjection of small interfering RNA (siRNA) adrenergic α2a receptor (ADRA2A) into the habenula, which showed a selective upregulation of α2 receptor gene expression after ICS, reversed the hyperalgesia but did not recover the morphine analgesia. However, both reversal of hyperalgesia and recovery of morphine analgesia were observed when siRNA ADRA2A was administered intracerebroventricularly. As the habenular is reported to be involved in the emotion/reward-related pain and hypoalgesia, these results suggest that mirtazapine could attenuate pain and/or augment hypoalgesia by blocking the habenular α2 receptor after ICS. The recovery of morphine analgesia in the ICS model, on the other hand, seems to be mediated through a blockade of α2 receptor in unidentified brain regions. SIGNIFICANCE STATEMENT: This study reports possible mechanisms underlying the complete reversal of hyperalgesia and recovery of morphine analgesia by mirtazapine, a unique antidepressant with adrenergic α2 and serotonergic receptor antagonist properties, in a type of intermittently repeated stress (ICS)-induced fibromyalgia-like pain model. Habenula, a brain region which is related to the control of emotional pain, was found to play key roles in the antihyperalgesia, whereas other brain regions appeared to be involved in the recovery of morphine analgesia in the ICS model.

Influence of Intermittent Cold Stimulations on CREB and Its Targeting Genes in Muscle: Investigations into Molecular Mechanisms of Local Cryotherapy.

Local cryotherapy is widely used as a treatment for sports-related skeletal muscle injuries. The molecular mechanisms are unknown. To clarify these mechanisms, we applied one to three 15-min cold stimulations at 4 °C to various cell lines (in vitro), the tibialis anterior (TA) muscle (ex vivo), and mouse limbs (in vivo). In the in vitro assay, cyclic AMP (cAMP) response element binding protein 1 (CREB1) was markedly phosphorylated (p-CREB1), and the CREB-binding protein (CBP) was recruited to p-CREB-1 in response to two or three cold stimulations. In a reporter assay with the cAMP-responsive element, the signals significantly increased after two to three cold stimulations at 4 °C. In the ex vivo study, CREB-targeting genes were significantly upregulated following two or three cold stimulations. The in vivo experiment disclosed that cold stimulation of a mouse limb for 9 days significantly increased mitochondrial DNA copy number and upregulated genes involved in mitochondrial biogenesis. The results suggest that local cryotherapy increases CREB transcription and upregulates CREB-targeting genes, in a manner dependent on cold stimulation frequency and duration. This information will inform further investigations into local cryotherapy as a treatment for sports-related skeletal muscle trauma.

Exercise Reverses the Alterations in Gut Microbiota Upon Cold Exposure and Promotes Cold-Induced Weight Loss.

Gut microbiota has been reported to contribute to reduced diet-induced obesity upon cold exposure. Furthermore, gut microbiome fermentation determines the efficacy of exercise for diabetes prevention and enhances exercise performance. However, there have been no systematic examinations of changes in gut microbiome composition in relation to exercise performed under low-temperature conditions. In this study, we investigated the effects of exercise performed under different conditions (room temperature, acute cold, intermittent cold, and sustained cold) in obese rats maintained on a high-fat diet at four time points during experimental trials (days 0, 1, 3, and 35), including observations on white fat browning, weight loss, cardiovascular effects, and changes in gut microbiota among treatment groups. We found that exercise under sustained cold conditions produced a remarkable shift in microbiota composition. Unexpectedly, exercise was found to reverse the alterations in gut microbiota alpha-diversity and the abundance of certain bacterial phyla observed in response to cold exposure (e.g., Proteobacteria decreased upon cold exposure but increased in response to exercise under cold conditions). Moreover, exercise under cold conditions (hereafter referred to “cold exercise”) promoted a considerably higher level of white fat browning and greater weight loss and protected against the negative cardiovascular effects of cold exposure. Correlation analysis revealed that cold exercise-related changes in gut microbial communities were significantly correlated with white fat browning and cardiovascular phenotypes. These results could reveal novel mechanisms whereby additional health benefits attributable to both cold and exercise are mediated via altered gut microbes differently compared with either of them alone.

NR2A-NMDA Receptor Blockade Reverses the Lack of Morphine Analgesia Without Affecting Chronic Pain Status in a Fibromyalgia-Like Mouse Model.

We have developed an experimental fibromyalgia-like mouse model using intermittent cold stress (ICS), where chronic pain is generalized, female predominant, and abolished in type 1 lysophosphatidic acid receptor-knockout (LPA1 -/-) mice but is not reversed by systemic or brain treatment with morphine. We investigated two issues in the present study: (1) whether chronic pain mechanisms and lack of brain morphine analgesia are associated in the ICS model and (2) what mechanisms are involved in the lack of morphine analgesia. ICS-induced hyperalgesia was not affected in μ-opioid receptor-knockout (MOPr -/-) mice, whereas the lack of brain morphine analgesia remained unchanged in LPA1 -/- mice, which completely abolished the hyperalgesia in the ICS model. In contrast, the lack of morphine analgesia was abolished in NR2A-NMDA receptor-knockout (NR2A -/- ) mice and blocked by intracerebroventricular (i.c.v.) injection of (R)-CPP, an NR2A antagonist, or by microinjection of siRNA NR2A into the periaqueductal gray matter region, whereas no change was observed with Ro 04-5595, an NMDA receptor subtype 2B antagonist (i.c.v.). The lack of morphine analgesia was also reversed by concomitant treatment with 1 mg/kg intraperitoneal (i.p.) of dextromethorphan, which possesses NMDA receptor antagonist activity but no analgesic activity. Finally, the hyperalgesia was completely reversed by methadone, which possesses both MOPr agonist and NMDA receptor antagonist activity. Indeed, methadone analgesia was abolished in MOPr -/- mice. These results suggest that chronic pain status and lack of morphine analgesia are independent of each other, and that lack of morphine analgesia is mediated by activation of the NR2A-NMDA receptor system. SIGNIFICANCE STATEMENT: This study reports that a type of intermittently repeated stress causes widespread pain that does not respond to morphine. Because this lack of morphine analgesia is not affected in mice, in which chronic pain is abolished, the mechanisms underlying chronic pain and lack of morphine analgesia are independent of each other. Through speculation that a lack of morphine analgesia may be a secondary event to endogenous opioid analgesic tolerance, the authors demonstrate that an antiopioid N-methyl-D-aspartate receptor system counterbalances the μ-opioid receptor-mediated analgesic mechanisms in the intermittent cold stress model.

Морфофункциональные изменения ободочной кишки и иммунные реакции при холодовом стрессе у самцов и самок мышей C57BL/6

Introduction. Stress is one of the factors contributing to the gastrointestinal tract diseases development and exacerbating the course of diseases of the gastrointestinal tract. The cold factor is the most common stress factor in Russia. Therefore, the aim of our work was to characterize the immune responses and colon morphological and functional changes during cold stress in male and female C57BL/6 mice. Materials and methods. We studied alterations in the subpopulation composition of peripheral blood lymphocytes and morphofunctional changes in the thymus, spleen, and colon in response to a course intermittent cold exposure during 35-minute sessions for 14 days at –20° in adult male and female C57BL/6 mice. Results. The volume fraction of the PALS zone of the spleen and the content of endocrine cells in the colon decreased in animals of both sexes in the cold stress conditions. In females, the number of platelets and leukocytes in the peripheral blood increased, the width of the subcapsular zone of the thymus decreased, and the volume fraction of the red spleen pulp increased. In males, in the peripheral blood, the absolute and relative content of T-regulatory lymphocytes decreased, and the relative content of activated T-helpers increased, the volume fraction of the light centers of lymphoid nodules in the spleen decreased, the length of the crypts increased in the colon. A number of differences between males and females of control groups were also revealed: in the peripheral blood, males had more platelets and the absolute content of T-regulatory lymphocytes and less absolute content of T-cytotoxic. In the colon of males, the content of proliferating epithelial cells in the colon was higher than the one in females, and the bulk density of goblet cells was lower in males. Conclusion. Under the cold stress factor exposure in animals, physiological stress develops. Immune reactions and colon morphofunctional changes in the colon during cold stress differ between males and females. Keywords:cold stress, sex differences, colon, immune system

Ciliary neurotrophic factor signaling in the rat orbitofrontal cortex ameliorates stress-induced deficits in reversal learning

Deficits in cognitive flexibility, i.e. the ability to modify behavior in response to changes in the environment, are present in several psychiatric disorders and are often refractory to treatment. However, improving treatment response has been hindered by a lack of understanding of the neurobiology of cognitive flexibility. Using a rat model of chronic stress (chronic intermittent cold stress, CIC) that produces selective deficits in reversal learning, a form of cognitive flexibility dependent on orbitofrontal cortex (OFC) function, we have previously shown that JAK2 signaling is required for optimal reversal learning. In this study we explore the molecular basis of those effects. We show that, within the OFC, CIC stress reduces the levels of phosphorylated JAK2 and of ciliary neurotrophic factor (CNTF), a promoter of neuronal survival and an activator of JAK2 signaling, and that neutralizing endogenous CNTF with an intra-OFC microinjection of a specific antibody is sufficient to produce reversal-learning deficits similar to stress. Intra-OFC delivery of recombinant CNTF to CIC-stressed rats, at a dose that induces JAK2 and Akt but not STAT3 or ERK, ameliorates reversal-learning deficits, and Akt blockade prevents the positive effects of CNTF. Further analysis revealed that CNTF may exert its beneficial effects by inhibiting GSK3β, a substrate of Akt and a regulator of protein degradation. We also revealed a novel mechanism of CNTF action through modulation of p38/Mnk1/eIF4E signaling. This cascade controls translation of select mRNAs, including those encoding several plasticity-related proteins. Thus, we suggest that CNTF-driven JAK2 signaling corrects stress-induced reversal learning deficits by modulating the steady-state levels of plasticity-related proteins in the OFC.

ASIC3-dependent metabolomics profiling of serum and urine in a mouse model of fibromyalgia

Fibromyalgia (FM) is characterized by chronic widespread pain. The pathogenesis of FM remains unclear. No specific biomarkers are available. Animal models of FM may provide an opportunity to explore potential biomarkers in a relative homogenous disease condition. Here, we probed the metabolomics profiles of serum and urine in a mouse model of FM induced by intermittent cold stress (ICS). We focused on the role of acid-sensing ion channel 3 (ASIC3) in the metabolomics profiling because ICS treatment induced chronic widespread muscle pain lasting for 1 month in wild-type (Asic3+/+) but not Asic3-knockout (Asic3−/−) mice. Serum and urine samples were collected from both genotypes at different ICS stages, including before ICS (basal level) and post-ICS at days 10 (middle phase, P10) and 40 (recovery phase, P40). Control naïve mice and ICS-induced FM mice differed in 1H-NMR- and LC-MS-based metabolomics profiling. On pathway analysis, the leading regulated pathways in Asic3+/+ mice were taurine and hypotaurine, cysteine and methionine, glycerophospholipid, and ascorbate and aldarate metabolisms, and the major pathways in Asic3−/− mice involved amino acid-related metabolism. Finally, we developed an algorithm for the impactful metabolites in the FM model including cis-aconitate, kynurenate, taurine, pyroglutamic acid, pyrrolidonecarboxylic acid, and 4-methoxyphenylacetic acid in urine as well as carnitine, deoxycholic acid, lysoPC(16:0), lysoPC(20:3), oleoyl-L-carnitine, and trimethylamine N-oxide in serum. Asic3−/− mice were impaired in only muscle allodynia development but not other pain symptoms in the ICS model, so the ASIC3-dependent metabolomics changes could be useful for developing diagnostic biomarkers specific to chronic widespread muscle pain, the core symptom of FM. Further pharmacological validations are needed to validate these metabolomics changes as potential biomarkers for FM diagnosis and/or treatment responses.

Plasma levels of matrix metalloproteinase-9: A possible marker for cold-induced stroke risk in hypertensive rats

The cold weather is associated with an increased occurrence of acute stroke events. However, the underlying mechanisms have not yet been fully elucidated. In the present study, we investigated whether plasma matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels as well as the MMP-9/TIMP-1 ratio could be used as predictor for cold-induced stroke risk in hypertensive rats. A total of 50 male rats were subjected to either control group or 2-kidney, 2-clip (2K – 2C) group (N = 25, each), After blood pressure was stabilized, rats were placed in an intelligent artificial climate chamber and maintained on a 12-h light (22 °C)/dark (4 °C) cycle for 3 days. Plasma levels of MMP-9 and TIMP-1 were measured before and after cold exposure from 50 rats by ELISA. Pretreatment plasma MMP-9 levels were significantly higher in 2K-2C rats than in the controls (P < 0.05), TIMP-1 levels were significantly lower in 2K-2C rats than in the controls (P < 0.05), pretreatment plasma MMP-9 levels were significantly higher in those with cold–induced stroke compared to those without (P < 0.05). Logistic regression analysis showed that only plasma MMP-9 levels remained independently associated with cold–induced stroke after adjusting for potential confounders (OR, 1.17; 95% CI, 1.08 to 1.32; P < 0.007). In contrast, no correlation was observed between systolic blood pressure (SBP), TIMP-1 or MMP-9/TIMP-1 ratio and the cold–induced stroke. Higher plasma MMP-9 levels are significantly correlated with cold-induced stroke in hypertensive rats treated with intermittent cold stress. Plasma MMP-9 may be as a promising biomarker to predict the risk of cold-induced stroke events in hypertensive rats.

Cardiac Surgery without Donor Blood Transfusion at a Referral Cardiac Institute in Bangladesh

Background: Blood transfusion is always associated with some hazards despite economic and work burden on laboratory staffs. Pre-donation and blood conservation can help to avoid transfusion related hazards with good posto-perative outcome.&#x0D; Objective: The main objective of this study was to show the varieties of cardiac surgery without donor blood transfusion.&#x0D; Methodology: Patients were selected conveniently. Preoperative proper counseling was done to the guardians of minor and all the adult patients about the procedure and written informed consent was taken accordingly. All patients were operated under cardio-pulmonary bypass (CPB) following a standard protocol through mid-sternotomy, systemic heparinization, antegrade intermittent cold cardioplegic arrest of the heart. After weaning from CPB protamine was administered to neutralize the action of heparin. A pre-operative hemoglobin (Hb) and hematocrit (Hct) measured just before systemic heparinization. One bag of blood drawn from the patient’s body when the Hb and Hct more. Meticulous hemostasis done after weaning from cardio-pulmonary bypass. Both systemic and local tranexamic acid plus calcium injection was given before sternal wires are tighten. All the blood in the cardio-pulmonary bypass machine was returned at the end of operation. Patient’s hemoglobin and hematocrit checked to detect the need for transfusion. All other variables were studied.&#x0D; Results: Ten patients were operated without pre-operative blood transfusion of donor blood. Out of ten patients male=5 female=5, Male:Female=1:1 age range 5-26 years mean ±SD (13±-6.88) years. Preop diagnosis ASD 4/10=40%,VSD 3/10=30% TOF 2/10=20% AVR=1/10=10%. pre-operative Hb Range: 12.4-17.3 gm/dl. Mean ±SD (14.25±-1.66 gm/dl. Pre-operative Hct mean±SD (43.7±4.5). Per-operative Hct during CPB Mean±SD (24.9±4). Post-operative Hb mean ±SD (11.25gm±1.18gm). Post-operative Hct mean ±SD (34.3±3.80). Use of cell saver 1/8(12.5%) Post-operative blood loss for ASD,VSD, TOF and AVR were mean ±SD = 140±20.60ml, 156.44±33.84.320.80±60.22ml and 280 ml respectively. Varieties of ionotropes used were: Dopamine Dobutamin Adrenaline. Single ionotrope Dopa/Dobuta5/10=50% Double ionotrope Dopa/dobuta+Adrin=3/10(30%) tripple ionotrope 2/10(20%). Morbidity and mortality 0%. All the patients were discharged home uneventfully, in hospital outcome was good.&#x0D; Conclusion: In our setup we can do cardiac surgery without pre-operative donor blood use by following blood pre-donation and other blood conservative techniques.]&#x0D; Journal of National Institute of Neurosciences Bangladesh, 2019;5(1): 53-58

Long-term intermittent cold exposure regulates glucose homeostasis via intervening metabolism of adipose tissue in mice

Long-term intermittent cold exposure regulates glucose homeostasis via intervening metabolism of adipose tissue in mice