Thermoneutrality and Immunity: How Does Cold Stress Affect Disease?

Cold-induced phosphatidylethanolamine synthesis in liver and brown adipose tissue of mice

Increasing energy expenditure in brown adipose (BAT) tissue by cold-induced lipolysis is discussed as a potential strategy to counteract imbalanced lipid homeostasis caused through unhealthy lifestyle and cardiometabolic disease. Yet, it is largely unclear how liberated fatty acids (FA) are metabolized. We investigated the liver and BAT lipidome of mice housed for 1 week at thermoneutrality, 23 °C and 4 °C using quantitative mass spectrometry-based lipidomics. Housing at temperatures below thermoneutrality triggered the generation of phosphatidylethanolamine (PE) in both tissues. Particularly, the concentrations of PE containing polyunsaturated fatty acids (PUFA) in their acyl chains like PE 18:0_20:4 were increased at cold. Investigation of the plasma's FA profile using gas chromatography coupled to mass spectrometry revealed a negative correlation of PUFA with unsaturated PE in liver and BAT indicating a flux of FA from the circulation into these tissues. Beta-adrenergic stimulation elevated intracellular levels of PE 38:4 and PE 40:6 in beige wildtype adipocytes, but not in adipose triglyceride lipase (ATGL)-deficient cells. These results imply an induction of PE synthesis in liver, BAT and thermogenic adipocytes after activation of the beta-adrenergic signaling cascade.

Validation of a non-food or water motivated effort-based foraging task as a measure of motivational state in male mice

Disorders of motivation such as apathy syndrome are highly prevalent across neurological disorders but do not yet have an agreed treatment approach. The use of translational behavioural models can provide a route through which to meaningfully screen novel drug targets. Methods that utilise food deprivation in contrived environments may lack the sensitivity to detect deficits in self-initiated behaviour, and may have limited translation to normal behaviour. Animals monitored in more naturalistic environments may display more ethologically-relevant behaviours of greater translational value. Here, we aimed to validate a novel, non-food or water motivated effort-based foraging task as a measure of motivational state in mice. In this task, the mouse can freely choose to exert effort to forage nesting material and shuttle it back to a safe and enclosed environment. The amount of nesting material foraged is used as a readout of motivational state. Acute dopaminergic modulation with haloperidol, amphetamine and methylphenidate, and two phenotypic models known to induce motivational deficits (healthy ageing and chronic administration of corticosterone) were used to validate this task. Consistent with other effort-based decision-making tasks we find that foraging behaviour is sensitive to acute modulation of dopaminergic transmission. We find that both phenotypic models induce differing deficits in various aspects of foraging behaviour suggesting that the task may be used to parse different behavioural profiles from distinct disease phenotypes. Thus, without requiring extended training periods or physiological deprivation, this task may represent a refined and translational preclinical measure of motivation.

Therapeutic Potential of Salvia miltiorrhiza Root Extract in Alleviating Cold-Induced Immunosuppression

The interaction between environmental stressors, such as cold exposure, and immune function significantly impacts human health. Research on effective therapeutic strategies to combat cold-induced immunosuppression is limited, despite its importance. In this study, we aim to investigate whether traditional herbal medicine can counteract cold-induced immunosuppression. We previously demonstrated that cold exposure elevated immunoglobulin G (IgG) levels in mice, similar to the effects of intravenous immunoglobulin (IVIg) treatments. This cold-induced rise in circulating IgG was mediated by the renin-angiotensin-aldosterone system and linked to vascular constriction. In our mouse model, the cold-exposed groups (4 °C) showed significantly elevated plasma IgG levels and reduced bacterial clearance compared with the control groups maintained at room temperature (25 °C), both indicative of immunosuppression. Using this model, with 234 mice divided into groups of 6, we investigated the potential of tanshinone IIA, an active compound in Salvia miltiorrhiza ethanolic root extract (SMERE), in alleviating cold-induced immunosuppression. Tanshinone IIA and SMERE treatments effectively normalized elevated plasma IgG levels and significantly improved bacterial clearance impaired by cold exposure compared with control groups injected with a vehicle control, dimethyl sulfoxide. Notably, bacterial clearance, which was impaired by cold exposure, showed an approximately 50% improvement following treatment, restoring immune function to levels comparable to those observed under normal temperature conditions (25 °C, p < 0.05). These findings highlight the therapeutic potential of traditional herbal medicine in counteracting cold-induced immune dysregulation, offering valuable insights for future strategies aimed at modulating immune function in cold environments. Further research could focus on isolating tanshinone IIA and compounds present in SMERE to evaluate their specific roles in mitigating cold-induced immunosuppression.

Exploring the impact of epidemiological and clinical factors on the progression of canine leishmaniosis by statistical and whole genome analyses: from breed predisposition to comorbidities

Canine leishmaniosis (CanL), caused by Leishmania infantum, is a complex disease of growing importance in Europe. Clinical manifestations result from the down-modulation of the host immune response through multiple host-parasite interactions. Although several factors might influence CanL progression, this is the first known study evaluating risk factors for its different clinical stages in a large referral hospital population (n = 35.669) from an endemic area, over a 20 year period. Genome-wide scans for selection signatures were also conducted to explore the genomic component of clinical susceptibility to L. infantum infection. The prevalence of CanL was 3.2% (16.7% stage I; 43.6% stage II; 32.1% stage III; 7.6% stage IV). Dog breed (crossbreed), bodyweight (<10 kg), living conditions (indoors), regular deworming treatment, and being vaccinated against Leishmania significantly decreased the transmission risk and the risk for developing severe clinical forms. Conversely, the detection of comorbidities was associated with advanced clinical forms, particularly chronic kidney disease, neoplasia, cryptorchidism, infectious tracheobronchitis and urate urolithiasis, although those did not impact the clinical outcome. Significant associations between an increased risk of severe clinical stages and findings in the anamnesis (renal or skin-related manifestations) and physical examination (ocular findings) were also detected, highlighting their diagnostic value in referred cases of CanL. Sixteen breeds were found to be significantly more susceptible to developing severe stages of leishmaniosis (e.g. Great Dane, Rottweiler, English Springer Spaniel, Boxer, American Staffordshire Terrier, Golden Retriever), while 20 breeds displayed a clinical resistantance phenotype and, thus, are more likely to mount an efficient immune response against L. infantum (e.g. Pointer, Samoyed, Spanish Mastiff, Spanish Greyhound, English Setter, Siberian Husky). Genomic analyses of these breeds retrieved 12 regions under selection, 63 candidate genes and pinpointed multiple biological pathways such as the IRE1 branch of the unfolded protein response, which could play a critical role in clinical susceptibility to L. infantum infection.

Impact of quality and transparency in scientific writing on the reduction of animal usage in experimental protocols: a review based in pertinent literature

The irreproducibility in scientific research has become a critical issue. Despite the essential role of rigorous methodology in constructing a scientific article, more than half of publications, on average, are considered non-reproducible. The implications of this irreproducibility extend to reliability problems, hindering progress in technological production and resulting in substantial financial losses. In the context of laboratory animal research, this work emphasizes the importance of choosing an appropriate experimental model within the 3R's principle (Refine, Reduce, Replace). This study specifically addresses a deficiency in data specification in scientific articles, revealing inadequacies in the description of crucial details, such as environmental conditions, diet, and experimental procedures. For this purpose, 124 articles from journals with relevant impact factors were analyzed, conducting a survey of data considered important for the reproducibility of studies. Important flaws in the presentation of data were identified in most of the articles evaluated. The results of this study highlight the need to improve the description of essential information, standardizing studies, and ensuring the reproducibility of experiments in areas such as metabolism, immunity, hormones, stress, among others, to enhance the reliability and reproduction of experimental results, aligning with international guidelines such as ARRIVE and PREPARE.

The roles of Hippo/YAP signaling pathway in physical therapy

Cellular behavior is regulated by mechanical signals within the cellular microenvironment. Additionally, changes of temperature, blood flow, and muscle contraction also affect cellular state and the development of diseases. In clinical practice, physical therapy techniques such as ultrasound, vibration, exercise, cold therapy, and hyperthermia are commonly employed to alleviate pain and treat diseases. However, the molecular mechanism about how these physiotherapy methods stimulate local tissues and control gene expression remains unknow. Fortunately, the discovery of YAP filled this gap, which has been reported has the ability to sense and convert a wide variety of mechanical signals into cell-specific programs for transcription, thereby offering a fresh perspective on the mechanisms by which physiotherapy treat different diseases. This review examines the involvement of Hippo/YAP signaling pathway in various diseases and its role in different physical therapy approaches on diseases. Furthermore, we explore the potential therapeutic implications of the Hippo/YAP signaling pathway and address the limitations and controversies surrounding its application in physiotherapy.

Adipose Tissue Inflammation: Linking Physiological Stressors to Disease Susceptibility

The study of adipose tissue (AT) is enjoying a renaissance. White, brown, and beige adipocytes are being investigated in adult animals, and the critical roles of small depots like perivascular AT are becoming clear. But the most profound revision of the AT dogma has been its cellular composition and regulation. Single-cell transcriptomic studies revealed that adipocytes comprise well under 50% of the cells in white AT, and a substantial portion of the rest are immune cells. Altering the function of AT resident leukocytes can induce or correct metabolic syndrome and, more surprisingly, alter adaptive immune responses to infection. Although the field is dominated by obesity research, conditions such as rapid lipolysis, infection, and heat stress impact AT immune dynamics as well. Recent findings in rodents lead to critical questions that should be explored in domestic livestock as potential avenues for improved animal resilience to stressors, particularly as animals age.

Extreme temperatures increase the risk of pediatric pneumonia: a systematic review and meta-analysis

Introduction

The impact of climate change on ambient temperatures threatens to worsen pediatric pneumonia-related outcomes considerably. This study examined the associations of temperature variation and extreme temperature with pediatric pneumonia-related events using a meta-analysis.

Methods

We systematically searched PubMed, Medline, Embase, and Web of Science databases for relevant literature, and the quality of evidence was assessed. Fixed and random-effects meta-analyses were performed to calculate the pooled relative risks (RRs) of the associations with pneumonia-related events.

Results

We observed that a 1°C temperature variation increased the RR of pneumonia events by 1.06-fold (95% confidence interval (CI): 1.03-1.10). A 1°C temperature variation increased the RR by 1.10-fold of the pediatric pneumonia hospital admissions (95% CI: 1.00-1.21) and 1.06-fold of the pediatric pneumonia emergency department visits (95% CI: 1.01-1.10). Extreme cold increased the RR by 1.25-fold of the pediatric pneumonia events (95% CI: 1.07-1.45). A 1°C temperature variation increased the RR of pneumonia events in children by 1.19-fold (95% CI: 1.08-1.32), girls by 1.03-fold (95% CI: 1.02-1.05), and in temperate climate zones by 1.07-fold (95% CI: 1.03-1.11). Moreover, an increase in extreme cold increased the RR of pneumonia events in children by 2.43-fold (95% CI: 1.72-3.43), girls by 1.96-fold (95% CI: 1.29-2.98) and in temperate climate zones by 2.76-fold (95% CI: 1.71-4.47).

Conclusion

Our study demonstrated that pediatric pneumonia events are more prevalent among children, particularly girls, and individuals residing in temperate climate zones. Climate change represents an emergent public health threat, affecting pediatric pneumonia treatment and prevention..

Systematic Review Registration

PROSPERO (CRD42022378610).

Association between Environmental Temperature and Survival in Gastroesophageal Cancers: A Population Based Study

BACKGROUND

Cold stress suppresses antitumor response in animal models, leading to tumor growth. Recent studies have also shown a negative correlation between the average annual temperature (AAT) and cancer incidence. We hypothesized that esophageal cancer (EC) and gastric cancer (GC) patients living in warmer climates have improved survival outcomes than those living in colder climates.

METHODS

We conducted a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database from 1996 to 2015. We retrieved the National Centers for Environmental Information data to calculate the county-level AAT. Cox multivariate regression models were performed to measure the association between temperature (measured continuously at diagnosis and in 5-degree increments) and OS/DSS, adjusting for variables. All associations were compared at a significance level of 0.05. The OS and DSS were summarized using Kaplan-Meier methods. All statistics were performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, USA).

RESULTS

A total of 17,408 EC patients were analyzed. The average age of the cohort was 65 years, 79% of which were males and 21% were females. Of them, 61.6% had adenocarcinoma, and 37.6% were squamous. After adjusting for covariates, patients in regions with an AAT > 53.5 °F had an 11% improvement in OS [HR 0.89 (95% CI 0.86-0.92), p < 0.0001] and 13% in DSS [HR 0.87 (95% CI 0.84-0.90), p < 0.0001]. When the temperature was analyzed in 5 °F increments, with each increment, there was a 3% improvement in OS [HR 0.97 (95% CI 0.96-0.98), p < 0.0001] and 4% in DSS [HR 0.96 (95% CI 0.95-0.97), p < 0.0001]. Subgroup analysis of squamous and adenocarcinoma showed similar results. These findings were validated in 20,553 GC patients. After adjusting for covariates, patients in regions with an AAT > 53.5 had a 13% improvement in OS [HR 0.87 (95% CI 0.85-0.90), p < 0.0001] and 14% in DSS [HR 0.86 (95% CI 0.83-0.89), p < 0.0001]. When analyzed in 5 °F increments, with each increment, there was a 4% improvement in OS [HR 0.96 (95% CI 0.952-0.971), p < 0.0001] and 4% in DSS [HR 0.96 (95% CI 0.945-0.965), p < 0.0001].

CONCLUSION

We showed for the first time that higher environmental temperatures are associated with significant improvements in OS and DSS in patients with gastro-esophageal cancers, notwithstanding the limitations of a retrospective database analysis. Further confirmatory and mechanistic studies are required to implement specific interventional strategies.

Effect of lethal total body irradiation on bone marrow chimerism, acute graft-versus-host disease, and tumor engraftment in mouse models: impact of different radiation techniques using low- and high-energy X-rays

PURPOSE

Effects of X‑ray energy levels used for myeloablative lethal total body irradiation (TBI) delivery prior to bone marrow transplantation (BMT) in preclinical mouse models were examined.

MATERIALS AND METHODS

In mouse models, single-fraction myeloablative TBI at a lethal dose was delivered using two different X‑ray devices, either low (160 kV cabinet irradiator) or high energy (6 MV linear accelerator), before semi-allogeneic hematopoietic stem-cell transplantation (HSCT) to ensure bone marrow (BM) chimerism, graft-versus-host disease (GVHD), and tumor engraftment. Recipient mice were clinically followed for 80 days after bone marrow transplantation (BMT). Flow cytometry was performed to assess donor chimerism and tumor engraftment in recipient mice.

RESULTS

Both X‑ray irradiation techniques delivered a 10 Gy single fraction of TBI, presented a lethal effect, and could allow near-complete early donor chimerism on day 13. However, low-energy irradiation increased T cells' alloreactivity compared to high-energy irradiation, leading to clinical consequences for GVHD and tumor engraftment outcomes. The alloreactive effect differences might be attributed to the distinction in inflammatory status of irradiated recipients at donor cell infusion (D0). Delaying donor cell administration (D1 after lethal TBI) attenuated T cells' alloreactivity and clinical outcomes in GVHD mouse models.

CONCLUSION

Different X‑ray irradiation modalities condition T cell alloreactivity in experimental semi-allogeneic BMT. Low-energy X‑ray irradiator induces a post-TBI inflammatory burst and exacerbates alloreactive reactions. This technical and biological information should be considered in interpreting GVHD/ graft-versus-leukemia effect results in mice experimental models of BMT.

Thermoneutrality or standard temperature: is there an ideal housing temperature to study the antisteatotic effects of green tea in obese mice?

Metabolic-associated fatty liver disease (MAFLD) is a condition characterized by excessive accumulation of triglycerides in hepatocytes, currently considered the number one cause of chronic liver disease. MAFLD is strongly associated with obesity, type 2 diabetes, hyperlipidaemia, and hypertension. Emphasis has been placed on the use of green tea (GT), produced from the Camellia sinensis plant, rich in antioxidants as polyphenols and catechins, on obesity and MAFLD treatment/prevention. Studies carried out in rodent models housed at a standard temperature (ST, 22°C) are being questioned as ST is a determining factor on generating changes in the physiology of immune response, and energy metabolism. On the other hand, it seems that thermoneutrality (TN, 28°C) represents a closer parallel to human physiology. In this perspective, we investigated the effects of GT (500 mg/kg of body weight, over 12 weeks, 5 days/week) by comparing mice housed at ST or TN in a model of MAFLD of diet-induced obese males C57Bl/6 mice. We show that the liver phenotype at TN exhibits a more severe MAFLD while GT ameliorates this condition. In parallel, GT restores the expression of genes involved in the lipogenic pathway, regardless of temperature, with slight modifications in lipolysis/fatty acid oxidation. We observed an increase promoted by GT in PPARα and PPARγ proteins independently of housing temperature and a dual pattern of bile acid synthesis. Thus, animals' conditioning temperature is a key factor that can interfere in the results involving obesity and MAFLD, although GT has beneficial effects against MAFLD independently of the housing temperature of mice.

Reduction in Cold Stress in an Innovative Metabolic Cage Housing System Increases Animal Welfare in Laboratory Mice

Housing in metabolic cages can induce a pronounced stress response. Metabolic cage systems imply housing mice on metal wire mesh for the collection of urine and feces in addition to monitoring food and water intake. Moreover, mice are single-housed, and no nesting, bedding, or enrichment material is provided, which is often argued to have a not negligible impact on animal welfare due to cold stress. We therefore attempted to reduce stress during metabolic cage housing for mice by comparing an innovative metabolic cage (IMC) with a commercially available metabolic cage from Tecniplast GmbH (TMC) and a control cage. Substantial refinement measures were incorporated into the IMC cage design. In the frame of a multifactorial approach for severity assessment, parameters such as body weight, body composition, food intake, cage and body surface temperature (thermal imaging), mRNA expression of uncoupling protein 1 (Ucp1) in brown adipose tissue (BAT), fur score, and fecal corticosterone metabolites (CMs) were included. Female and male C57BL/6J mice were single-housed for 24 h in either conventional Macrolon cages (control), IMC, or TMC for two sessions. Body weight decreased less in the IMC (females-1st restraint: -6.94%; 2nd restraint: -6.89%; males-1st restraint: -8.08%; 2nd restraint: -5.82%) compared to the TMC (females-1st restraint: -13.2%; 2nd restraint: -15.0%; males-1st restraint: -13.1%; 2nd restraint: -14.9%) and the IMC possessed a higher cage temperature (females-1st restraint: 23.7 °C; 2nd restraint: 23.5 °C; males-1st restraint: 23.3 °C; 2nd restraint: 23.5 °C) compared with the TMC (females-1st restraint: 22.4 °C; 2nd restraint: 22.5 °C; males-1st restraint: 22.6 °C; 2nd restraint: 22.4 °C). The concentration of fecal corticosterone metabolites in the TMC (females-1st restraint: 1376 ng/g dry weight (DW); 2nd restraint: 2098 ng/g DW; males-1st restraint: 1030 ng/g DW; 2nd restraint: 1163 ng/g DW) was higher compared to control cage housing (females-1st restraint: 640 ng/g DW; 2nd restraint: 941 ng/g DW; males-1st restraint: 504 ng/g DW; 2nd restraint: 537 ng/g DW). Our results show the stress potential induced by metabolic cage restraint that is markedly influenced by the lower housing temperature. The IMC represents a first attempt to target cold stress reduction during metabolic cage application thereby producing more animal welfare friendlydata.

Assessment of cold exposure-induced metabolic changes in mice using untargeted metabolomics

Background: Cold exposure (CE) can effectively modulate adipose tissue metabolism and improve metabolic health. Although previous metabolomics studies have primarily focused on analyzing one or two samples from serum, brown adipose tissue (BAT), white adipose tissue (WAT), and liver samples, there is a significant lack of simultaneous analysis of multiple tissues regarding the metabolic changes induced by CE in mice. Therefore, our study aims to investigate the metabolic profiles of the major tissues involved. Methods: A total of 14 male C57BL/6J mice were randomly assigned to two groups: the control group (n = 7) and the CE group (n = 7). Metabolite determination was carried out using gas chromatography-mass spectrometry (GC-MS), and multivariate analysis was employed to identify metabolites exhibiting differential expression between the two groups. Results: In our study, we identified 32 discriminant metabolites in BAT, 17 in WAT, 21 in serum, 7 in the liver, 16 in the spleen, and 26 in the kidney, respectively. Among these metabolites, amino acids, fatty acids, and nucleotides emerged as the most significantly altered compounds. These metabolites were found to be associated with 12 differential metabolic pathways closely related to amino acids, fatty acids, and energy metabolism. Conclusion: Our study may provide valuable insights into the metabolic effects induced by CE, and they have the potential to inspire novel approaches for treating metabolic diseases.

Diversity and inclusion for rodents: how animal ethics committees can help improve translation

Translation failure occurs when a treatment shown to be safe and effective in one type of population does not produce the same result in another. We are currently in a crisis involving the translatability of preclinical studies to human populations. Animal trials are no better than a coin toss at predicting the safety and efficacy of drugs in human trials, and the high failure rate of drugs entering human trials suggests that most of the suffering of laboratory animals is futile, creating no commensurate benefit for human patients. Here, I argue that animal ethics committees have a role to play in getting us out of this crisis. Inadequate representation is a known contributor to translation failures and is a matter of both scientific and ethical concern. Ethical review committees have the authority to address it by reprioritising the values already enshrined in their guiding principles.

Housing temperature plays a critical role in determining gut microbiome composition in research mice: Implications for experimental reproducibility

Preclinical mouse models are widely used for studying mechanisms of disease and responses to therapeutics, however there is concern about the lack of experimental reproducibility and failure to predict translational success. The gut microbiome has emerged as a regulator of metabolism and immunological processes in health and disease. The gut microbiome of mice differs by supplier and this affects experimental outcomes. We have previously reported that the mandated, mildly cool housing temperature for research mice (22°-26 °C) induces chronic adrenergic stress which suppresses anti-tumor immunity and promotes tumor growth compared to thermoneutral housing (30 °C). Therefore, we wondered how housing temperature affects the microbiome. Here, we demonstrate that the gut microbiome of BALB/c mice is easily modulated by a few degrees difference in temperature. Our results reveal significant differences between the gut microbiome of mice housed at 22°-23 °C vs. 30 °C. Although the genera vary, we consistently observed an enrichment of members of the family Lachnospiraceae when mice are housed at 22°-23 °C. These findings demonstrate that adrenergic stress and need for increased energy harvest to support thermogenesis, in addition to other factors such as diet, modulates the gut microbiome and this could be one mechanism by which housing temperature affects experimental outcomes. Additionally, tumor growth in mice housed at 30 °C also increases the proportion of Lachnospiraceae. The idea that stress can alter the gut microbiome and cause differences in experimental outcomes is applicable to mouse studies in general and is a variable that has significant potential to affect experimental reproducibility.

Thermoneutrality and severe malaria: investigating the effect of warmer environmental temperatures on the inflammatory response and disease progression

Introduction

Most studies using murine disease models are conducted at housing temperatures (20 - 22°C) that are sub-optimal (ST) for mice, eliciting changes in metabolism and response to disease. Experiments performed at a thermoneutral temperature (TT; 28 - 31°C) have revealed an altered immune response to pathogens and experimental treatments in murine disease model that have implications for their translation to clinical research. How such conditions affect the inflammatory response to infection with Plasmodium berghei ANKA (PbA) and disease progression is unknown. We hypothesized that changes in environmental temperature modulate immune cells and modify host response to malaria disease. To test this hypothesis, we conducted experiments to determine: (1) the inflammatory response to malarial agents injection in a peritonitis model and (2) disease progression in PbA-infected mice at TT compared to ST.

Methods

In one study, acclimatized mice were injected intraperitoneally with native hemozoin (nHZ) or Leishmania at TT (28 - 31°C) or ST, and immune cells, cytokine, and extracellular vesicle (EV) profiles were determined from the peritoneal cavity (PEC) fluid. In another study, PbA-infected mice were monitored until end-point (i.e. experimental malaria score ≥4).

Results

We found that Leishmania injection resulted in decreased cell recruitment and higher phagocytosis of nHZ in mice housed at TT. We found 398 upregulated and 293 downregulated proinflammatory genes in mice injected with nHZ, at both temperatures. We report the presence of host-derived EVs never reported before in a murine parasitic murine model at both temperatures. We observed metabolic changes in mice housed at TT, but these did not result to noticeable changes in disease progression compared to ST.

Discussion

To our knowledge, these experiments are the first to investigate the effect of thermoneutrality on a malaria murine model. We found important metabolic difference in mice housed at TT. Our results offer insights on how thermoneutrality might impact a severe malaria murine model and directions for more targeted investigations.

Small changes in thermoregulation influence cancellous bone turnover balance in distal femur metaphysis in growing female mice

Mice are typically housed at temperatures well below their thermoneutral zone. When individually housed at room temperature (~22 °C) mice experience cold stress which results in cancellous bone loss and has the potential to alter the skeletal response to treatment. It is not clear if there is a threshold temperature for cold stress-induced bone loss. It is also not clear if alternative strategies for attenuating cold stress, such as group housing, influence bone accrual and turnover. This study aimed to determine how small differences in temperature (4 °C) or heat loss (individual versus group housing with nestlets) influence bone in growing female C57BL/6 J mice. Five-week-old mice were randomized by weight to 1 of 4 treatment groups (N = 10/group): 1) baseline, 2) single housed at 22 °C, 3) single housed at 26 °C, or 4) group housed (n = 5/cage) with nestlets at 22 °C. Mice in the baseline group were sacrificed 1 week later, at 6 weeks of age. The other 3 groups of mice were maintained at their respective temperatures and housing conditions for 13 weeks until 18 weeks of age. Compared to baseline, mice single housed at room temperature had increased body weight and femur size, but dramatically decreased cancellous bone volume fraction in distal femur metaphysis. The cancellous bone loss was attenuated but not prevented in mice individually housed at 26 °C or group housed at 22 °C. In conclusion, by impacting thermogenesis or heat loss, modest differences in housing conditions could influence experimental results.

Integrative network fusion-based multi-omics study for biomarker identification and patient classification of rheumatoid arthritis

BACKGROUND

Cold-dampness Syndrome (RA-Cold) and Hot-dampness Syndrome (RA-Hot) are two distinct groups of rheumatoid arthritis (RA) patients with different clinical symptoms based on traditional Chinese medicine (TCM) theories and clinical empirical knowledge. However, the biological basis of the two syndromes has not been fully elucidated, which may restrict the development of personalized medicine and drug discovery for RA diagnosis and therapy.

METHODS

An integrative strategy combining clinical transcriptomics, phenomics, and metabolomics data based on clinical cohorts and adjuvant-induced arthritis rat models was performed to identify novel candidate biomarkers and to investigate the biological basis of RA-Cold and RA-Hot.

RESULTS

The main clinical symptoms of RA-Cold patients are joint swelling, pain, and contracture, which may be associated with the dysregulation of T cell-mediated immunity, osteoblast differentiation, and subsequent disorders of steroid biosynthesis and phenylalanine metabolism. In contrast, the main clinical symptoms of RA-Hot patients are fever, irritability, and vertigo, which may be associated with various signals regulating angiogenesis, adrenocorticotropic hormone release, and NLRP3 inflammasome activation, leading to disorders of steroid biosynthesis, nicotinamide, and sphingolipid metabolism. IL17F, 5-HT, and IL4I1 were identified as candidate biomarkers of RA-Cold, while S1P and GLNS were identified as candidate biomarkers of RA-Hot.

CONCLUSIONS

The current study presents the most comprehensive metabonomic and transcriptomic profiling of serum, urine, synovial fluid, and synovial tissue samples obtained from RA-Cold and RA-Hot patients and experimental animal models to date. Through the integration of multi-omics data and clinical independent validation, a list of novel candidate biomarkers of RA-Cold and RA-Hot syndromes were identified, that may be useful in improving RA diagnosis and therapy.

Preparation of oral nanoparticles of Perillae Fructus oil and prevention application of cold stress in mice

Perillae Fructus oil has an important function in relieving cold stress. However, its application in this aspect has still been restricted because of instability and low bioavailability. In this study, Perillae Fructus oil was extracted through Soxhlet extraction, analyzed through gas chromatography-mass spectrometry (GC-MS), and nanopackaged into a yeast shell for the preparation of nanoparticles for oral administration. The characteristics of the nanoparticles were investigated using a Malvern zeta-size nanoinstrument, scanning electron microscopy (SEM), and high-performance liquid chromatography (HPLC). Then, the roles of orally administered nanoparticles in relieving cold stress were evaluated by investigating blood physiological and biochemical indexes in mice. The results showed that the oil yield from Perillae Fructus and shell yield from yeast cells were ~48.37% and ~16.87%, respectively. Approximately 89.21% of the added oil was packaged into the yeast shell to form nanoparticles with an average diameter of 316.74 nm and a surface charge of +2.9 mV. The nanoparticles were stable in simulated gastric acid and could be effectively released in simulated intestinal fluid with an efficiency of ~91.34%. After oral administration of nanoparticles, the mouse blood indexes of white blood cells (WBCs), superoxide dismutase (SOD) activity, and malonaldehyde (MDA) content were recovered compared to those in model mice, with a more remarkable effect than oral administration of free Perillae Fructus oil. Overall, the stability and bioavailability were improved by packaging Perillae Fructus oil into a yeast shell. These nanoparticles are a new agent for the prevention of cold stress.

The Influence of Ambient Temperature on Adipose Tissue Homeostasis, Metabolic Diseases and Cancers

Adipose tissue is a recognized energy storage organ during excessive energy intake and an endocrine and thermoregulator, which interacts with other tissues to regulate systemic metabolism. Adipose tissue dysfunction is observed in most obese mouse models and humans. However, most studies using mouse models were conducted at room temperature (RT), where mice were chronically exposed to mild cold. In this condition, energy use is prioritized for thermogenesis to maintain body temperature in mice. It also leads to the activation of the sympathetic nervous system, followed by the activation of β-adrenergic signaling. As humans live primarily in their thermoneutral (TN) zone, RT housing for mice limits the interpretation of disease studies from mouse models to humans. Therefore, housing mice in their TN zone (~28–30 °C) can be considered to mimic humans physiologically. However, factors such as temperature ranges and TN pre-acclimatization periods should be examined to obtain reliable results. In this review, we discuss how adipose tissue responds to housing temperature and the outcomes of the TN zone in metabolic disease studies. This review highlights the critical role of TN housing in mouse models for studying adipose tissue function and human metabolic diseases.

The metabolic cost of physical activity in mice using a physiology-based model of energy expenditure

OBJECTIVE

Physical activity is a major component of total energy expenditure (TEE) that exhibits extreme variability in mice. Our objective was to construct a general, physiology-based model of TEE to accurately quantify the energy cost of physical activity.

METHODS

Spontaneous home cage physical activity, body temperature, TEE, and energy intake were measured with frequent sampling. The energy cost of activity was modeled considering six contributors to TEE (basal metabolic rate, thermic effect of food, body temperature, cold induced thermogenesis, physical activity, and body weight). An ambient temperature of 35 °C was required to remove the contribution from cold induced thermogenesis. Basal metabolic rate was adjusted for body temperature using a Q₁₀ temperature coefficient.

RESULTS

We developed a TEE model that robustly explains 70-80% of the variance in TEE at 35 °C while fitting only two parameters, the basal metabolic rate and the mass-specific energy cost per unit of physical activity, which averaged 60 cal/km/g body weight. In Ucp1^-/- mice the activity cost was elevated by 60%, indicating inefficiency and increased muscle thermogenesis. The diurnal rhythm in TEE was quantitatively explained by the combined diurnal differences in physical activity, body temperature, and energy intake.

CONCLUSIONS

The physiology-based model of TEE allows quantifying the energy cost of physical activity. While applied here to mice, the model should be generally valid across species. Due to the effect of body temperature, we suggest that basal metabolic rate measurements be corrected to a reference body temperature, including in humans. Having an accurate cost of physical activity allows mechanistic dissection of disorders of energy homeostasis, including obesity.

Warmer ambient air temperatures reduce nasal turbinate and brain infection, but increase lung inflammation in the K18-hACE2 mouse model of COVID-19

Warmer climatic conditions have been associated with fewer COVID-19 cases. Herein we infected K18-hACE2 mice housed at the standard animal house temperature of ∼22 °C, or at ∼31 °C, which is considered to be thermoneutral for mice. On day 2 post infection, RNA-Seq analyses showed no significant differential gene expression lung in lungs of mice housed at the two temperatures, with almost identical viral loads and type I interferon responses. There was also no significant difference in viral loads in lungs on day 5, but RNA-Seq and histology analyses showed clearly elevated inflammatory signatures and infiltrates. Thermoneutrality thus promoted lung inflammation. On day 2 post infection mice housed at 31 °C showed reduced viral loads in nasal turbinates, consistent with increased mucociliary clearance at the warmer ambient temperature. These mice also had reduced virus levels in the brain, and an ensuing amelioration of weight loss and a delay in mortality. Warmer air temperatures may thus reduce infection of the upper respiratory track and the olfactory epithelium, resulting in reduced brain infection. Potential relevance for anosmia and neurological sequelae in COVID-19 patients is discussed.

Green tea beneficial effects involve changes in the profile of immune cells in the adipose tissue of obese mice

PURPOSE

During obesity, the adipose tissue is usually infiltrated by immune cells which are related to hallmarks of obesity such as systemic inflammation and insulin resistance (IR). Green tea (GT) has been widely studied for its anti-inflammatory actions, including the modulation in the proliferation and activity of immune cells, in addition to preventing cardiovascular and metabolic diseases.

METHODS

The aim of the present study was to analyze the population of immune cells present in the subcutaneous and epididymal white adipose tissue (WAT) of mice kept at thermoneutrality (TN) and fed with a high-fat diet (HFD) for 16 weeks, supplemented or not with GT extract (500 mg/kg/12 weeks).

RESULTS

The HFD in association with TN has induced chronic inflammation, and IR in parallel with changes in the profile of immune cells in the subcutaneous and epidydimal WAT, increasing pro-inflammatory cytokines release, inflammatory cells infiltration, and fibrotic aspects in WAT. On the other hand, GT prevented body weight gain, in addition to avoiding IR and inflammation, and the consequent tissue fibrosis, maintaining a lower concentration of cytokines and a profile of immune cells similar to the control mice, preventing the harmful modulations induced by both HFD and TN.

CONCLUSIONS

GT beneficial effects in WAT abrogated the deleterious effects triggered by HFD and TN, maintaining all immune cells and fibrotic markers at the same level as in lean mice. These results place WAT immune cells population as a potential target of GT action, also highlighting the positive effects of GT in obese mice housed at TN.

How stable is your vivarium's temperature? Fluctuations in vivarium temperature significantly impact metabolism and behavior impeding scientific reproducibility

OBJECTIVES

The purpose of this investigation was to examine the variability in vivarium temperature and the impact that this has on metabolic and behavioral outcomes in mice.

METHODS

Daily vivarium temperature was monitored every day for a two-year period. Behavioral and metabolic phenotyping were assessed in male and female C57BL/6 (n = 71/sex) mice over the course of 2 years.

RESULTS

Vivarium temperature was found to fluctuate on a monthly, daily, and even an hourly basis of approximately ±5ºC. A 5ºC change in temperature was found to result in daily changes in total energy expenditure (35% and 27%), resting energy expenditure (39% for both sexes), movement (51% and 37%), food consumption (35% and 29%), and sleep duration (15% and 13%) for female and male mice, respectively.

CONCLUSIONS

Fluctuations in vivarium temperature can dramatically impact metabolic and behavioral outcomes, which impedes scientific reproducibility. This awareness and the guidelines we propose in this publication will hopefully help to enhance the reproducibility of pre-clinical animal research.

Endothelial SIRT-1 has a critical role in the maintenance of capillarization in brown adipose tissue

Brown adipose tissue (BAT) has critical roles in thermogenesis and systemic metabolism. Capillary rarefaction was reported to develop in BAT with dietary obesity, and previous studies showed that suppression of vascular endothelial growth factor A (VEGF-A) reduced capillary density in BAT, promoting the functional decline of this organ. Capillarization is regulated through the balance between angiogenesis and vasculogenesis on the one hand and apoptosis of endothelial cells (ECs) on the other; however, the role of EC apoptosis in BAT remained to be explored. In studies testing the role of boysenberry polyphenols (BoyP) in BAT, we found that BoyP decreased EC apoptosis, enhanced capillarization in BAT, and ameliorated dietary BAT dysfunction, which was associated with the upregulation of nicotinamide adenine dinucleotide-dependent protein deacetylase sirtuin 1 (SIRT-1) in ECs. Our studies suggest that EC SIRT-1 would be one of the potential targets of BoyP that contributes to BAT capillarization and function.

Climate change, human health, and the exposome: Utilizing OMIC technologies to navigate an era of uncertainty

Climate change is an anthropogenic phenomenon that is alarming scientists and non-scientists alike. The emission of greenhouse gases is causing the temperature of the earth to rise and this increase is accompanied by a multitude of climate change-induced environmental exposures with potential health impacts. Tracking human exposure has been a major research interest of scientists worldwide. This has led to the development of exposome studies that examine internal and external individual exposures over their lifetime and correlate them to health. The monitoring of health has also benefited from significant technological advances in the field of "omics" technologies that analyze physiological changes on the nucleic acid, protein, and metabolism levels, among others. In this review, we discuss various climate change-induced environmental exposures and their potential health implications. We also highlight the potential integration of the technological advancements in the fields of exposome tracking, climate monitoring, and omics technologies shedding light on important questions that need to be answered.

Low Environmental Temperature Exacerbates Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Golden Syrian Hamsters

BACKGROUND

The effect of low environmental temperature on viral shedding and disease severity of Coronavirus Disease 2019 (COVID-19) is uncertain.

METHODS

We investigated the virological, clinical, pathological, and immunological changes in hamsters housed at room (21°C), low (12-15°C), and high (30-33°C) temperature after challenge by 105 plaque-forming units of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

RESULTS

The nasal turbinate, trachea, and lung viral load and live virus titer were significantly higher (~0.5-log10 gene copies/β-actin, P < .05) in the low-temperature group at 7 days postinfection (dpi). The low-temperature group also demonstrated significantly higher level of tumor necrosis factor-α, interferon-γ (IFN-γ), interleukin-1β, and C-C motif chemokine ligand 3, and lower level of the antiviral IFN-α in lung tissues at 4 dpi than the other 2 groups. Their lungs were grossly and diffusely hemorrhagic, with more severe and diffuse alveolar and peribronchiolar inflammatory infiltration, bronchial epithelial cell death, and significantly higher mean total lung histology scores. By 7 dpi, the low-temperature group still showed persistent and severe alveolar inflammation and hemorrhage, and little alveolar cell proliferative changes of recovery. The viral loads in the oral swabs of the low-temperature group were significantly higher than those of the other two groups from 10 to 17 dpi by about 0.5-1.0 log10 gene copies/β-actin. The mean neutralizing antibody titer of the low-temperature group was significantly (P < .05) lower than that of the room temperature group at 7 dpi and 30 dpi.

CONCLUSIONS

This study provided in vivo evidence that low environmental temperature exacerbated the degree of virus shedding, disease severity, and tissue proinflammatory cytokines/chemokines expression, and suppressed the neutralizing antibody response of SARS-CoV-2-infected hamsters. Keeping warm in winter may reduce the severity of COVID-19.

Genetic and genomic analysis of oxygen consumption in mice

We estimated genetic parameters for oxygen consumption (OC), OC per metabolic body weight (OCMBW) and body weight at three through 8 weeks of age in divergently selected mice populations, with an animal model considering maternal genetic, common litter environmental and cytoplasmic inheritance effects. Cytoplasmic inheritance was considered based on maternal lineage information. With respect to OC, estimated direct heritability was moderate (0.32) and the estimated proportion of the variance of cytoplasmic inheritance effects to the phenotypic variance was very low (0.01), implying that causal genes for OC could be located on autosomes. To assess this hypothesis, we attempted to identify possible candidate causal genes through selective signature detection with the results of pooled whole-genome resequencing using pooled DNA samples from high and low OC mice. We made a list of possible candidate causal genes for OC, including those relating to electron transport chain and ATP-binding proteins (Ndufa12, Sdhc, Atp10b, etc.), Prr16 encoding Largen protein, Cry1 encoding a key component of the circadian core oscillator and so on. The results, although careful interpretation must be required, could contribute to elucidate the genetic mechanism of OC, an indicator for maintenance energy requirement, and therefore feed efficiency.

The immunomodulatory effects of social isolation in mice are linked to temperature control

Living in isolation is considered an emerging societal problem that negatively affects the physical wellbeing of its sufferers in ways that we are just starting to appreciate. This study investigates the immunomodulatory effects of social isolation in mice, utilising a two-week program of sole cage occupancy followed by the testing of immune-inflammatory resilience to bacterial sepsis. Our results revealed that mice housed in social isolation showed an increased ability to clear bacterial infection compared to control socially housed animals. These effects were associated with specific changes in whole blood gene expression profile and an increased production of classical pro-inflammatory cytokines. Interestingly, equipping socially isolated mice with artificial nests as a substitute for their natural huddling behaviour reversed the increased resistance to bacterial sepsis. Together these results suggest that the control of body temperature through social housing and huddling behaviour are important factors in the regulation of the host immune response to infection in mice and might provide another example of the many ways by which living conditions influence immunity.

Transient Receptor Potential (TRP) and Thermoregulation in Animals: Structural Biology and Neurophysiological Aspects

This review presents and analyzes recent scientific findings on the structure, physiology, and neurotransmission mechanisms of transient receptor potential (TRP) and their function in the thermoregulation of mammals. The aim is to better understand the functionality of these receptors and their role in maintaining the temperature of animals, or those susceptible to thermal stress. The majority of peripheral receptors are TRP cation channels formed from transmembrane proteins that function as transductors through changes in the membrane potential. TRP are classified into seven families and two groups. The data gathered for this review include controversial aspects because we do not fully know the mechanisms that operate the opening and closing of the TRP gates. Deductions, however, suggest the intervention of mechanisms related to G protein-coupled receptors, dephosphorylation, and ligands. Several questions emerge from the review as well. For example, the future uses of these data for controlling thermoregulatory disorders and the invitation to researchers to conduct more extensive studies to broaden our understanding of these mechanisms and achieve substantial advances in controlling fever, hyperthermia, and hypothermia.

Leptin and environmental temperature as determinants of bone marrow adiposity in female mice

Bone marrow adipose tissue (BMAT) levels are higher in distal femur metaphysis of female mice housed at thermoneutral (32°C) than in mice housed at 22°C, as are abdominal white adipose tissue (WAT) mass, and serum leptin levels. We performed two experiments to explore the role of increased leptin in temperature-enhanced accrual of BMAT. First, we supplemented 6-week-old female C57BL/6J (B6) mice with leptin for 2 weeks at 10 µg/d using a subcutaneously implanted osmotic pump. Controls consisted of ad libitum (ad lib) fed mice and mice pair fed to match food intake of leptin-supplemented mice. The mice were maintained at 32°C for the duration of treatment. At necropsy, serum leptin in leptin-supplemented mice did not differ from ad lib mice, suggesting suppression of endogenous leptin production. In support, Ucp1 expression in BAT, percent body fat, and abdominal WAT mass were lower in leptin-supplemented mice. Leptin-supplemented mice also had lower BMAT and higher bone formation in distal femur metaphysis compared to the ad lib group, changes not replicated by pair-feeding. In the second experiment, BMAT response was evaluated in 6-week-old female B6 wild type (WT), leptin-deficient ob/ob and leptin-treated (0.3 μg/d) ob/ob mice housed at 32°C for the 2-week duration of the treatment. Compared to mice sacrificed at baseline (22°C), BMAT increased in ob/ob mice as well as WT mice, indicating a leptin independent response to increased temperature. However, infusion of ob/ob mice with leptin, at a dose rate having negligible effects on either energy metabolism or serum leptin levels, attenuated the increase in BMAT. In summary, increased housing temperature and increased leptin have independent but opposing effects on BMAT in mice.

Experimental Applications and Factors Involved in Validating Thermal Windows Using Infrared Thermography to Assess the Health and Thermostability of Laboratory Animals

Evaluating laboratory animals' health and thermostability are fundamental components of all experimental designs. Alterations in either one of these parameters have been shown to trigger physiological changes that can compromise the welfare of the species and the replicability and robustness of the results obtained. Due to the nature and complexity of evaluating and managing the species involved in research protocols, non-invasive tools such as infrared thermography (IRT) have been adopted to quantify these parameters without altering them or inducing stress responses in the animals. IRT technology makes it possible to quantify changes in surface temperatures that are derived from alterations in blood flow that can result from inflammatory, stressful, or pathological processes; changes can be measured in diverse regions, called thermal windows, according to their specific characteristics. The principal body regions that were employed for this purpose in laboratory animals were the orbital zone (regio orbitalis), auricular pavilion (regio auricularis), tail (cauda), and the interscapular area (regio scapularis). However, depending on the species and certain external factors, the sensitivity and specificity of these windows are still subject to controversy due to contradictory results published in the available literature. For these reasons, the objectives of the present review are to discuss the neurophysiological mechanisms involved in vasomotor responses and thermogenesis via BAT in laboratory animals and to evaluate the scientific usefulness of IRT and the thermal windows that are currently used in research involving laboratory animals.

A longitudinal study on PRRSV detection in swine herds with different demographics and PRRSV management strategies

Porcine reproductive and respiratory syndrome virus (PRRSV) has been one of the major health-related concerns in the swine production industry. Through its rapid transmission and mutation, the simultaneous circulation of multiple PRRSV strains can be a challenge in PRRSV diagnostic, control and surveillance. The objective of this longitudinal study was to describe the temporal detection of PRRSV in swine farms with different production types and PRRS management strategies. Tonsil scraping (n = 344) samples were collected from three breeding and two growing herds for approximately one year. In addition, processing fluids (n = 216) were obtained from piglet processing batches within the three breeding farms while pen-based oral fluids (n = 125) were collected in the two growing pig farms. Viral RNA extraction and reverse-transcription quantitative PCR (RT-qPCR) were conducted for all samples. The sample positivity threshold was set at quantification cycle (Cq) of ≤ 37. Statistical analyses were performed using generalized linear modelling and post hoc pairwise comparisons with Bonferroni adjustments using R statistical software. The results suggested a higher probability of detection in processing fluids compared to tonsil scraping specimens [odds ratio (OR) = 3.86; p = .096] in breeding farms whereas oral fluids were outperformed by tonsil scrapings (OR = 0.26; p < .01) in growing pig farms. The results described herein may lead to an improvement in PRRSV diagnostic and surveillance by selecting proper specimens.

Blowing Hot and Cold: Body Temperature and the Microbiome

The intestinal microbiome influences host health, and its responsiveness to diet and disease is increasingly well studied. However, our understanding of the factors driving microbiome variation remain limited. Temperature is a core factor that controls microbial growth, but its impact on the microbiome remains to be fully explored. Although commonly assumed to be a constant 37°C, normal body temperatures vary across the animal kingdom, while individual body temperature is affected by multiple factors, including circadian rhythm, age, environmental temperature stress, and immune activation. Changes in body temperature via hypo- and hyperthermia have been shown to influence the gut microbiota in a variety of animals, with consistent effects on community diversity and stability. It is known that temperature directly modulates the growth and virulence of gastrointestinal pathogens; however, the effect of temperature on gut commensals is not well studied. Further, body temperature can influence other host factors, such as appetite and immunity, with indirect effects on the microbiome. In this minireview, we discuss the evidence linking body temperature and the intestinal microbiome and their implications for microbiome function during hypothermia, heat stress, and fever.

Leanness and Low Plasma Leptin in GPR17 Knockout Mice Are Dependent on Strain and Associated With Increased Energy Intake That Is Not Suppressed by Exogenous Leptin

Previous studies have shown that agonists of GPR17 stimulate, while antagonists inhibit feeding. However, whole body knockout of GPR17 in mice of the C57Bl/6 strain did not affect energy balance, whereas selective knockout in oligodendrocytes or pro-opiomelanocortin neurons provided protection from high fat diet-induced obesity and impaired glucose homeostasis. We reasoned that whole body knockout of GPR17 in mice of the 129 strain might elicit more marked effects because the 129 strain is more susceptible than the C57Bl/6 strain to increased sympathetic activity and less susceptible to high fat diet-induced obesity. Consistent with this hypothesis, compared to wild-type mice, and when fed on either a chow or a high fat diet, GPR17 -/- mice of the 129 strain displayed increased expression of uncoupling protein-1 in white adipose tissue, lower body weight and fat content, reduced plasma leptin, non-esterified fatty acids and triglycerides, and resistance to high fat diet-induced glucose intolerance. Not only energy expenditure, but also energy intake was raised. Administration of leptin did not suppress the increased food intake in GPR17 -/- mice of the 129 strain, whereas it did suppress food intake in GPR17 +/+ mice. The only difference between GPR17 +/- and GPR17 +/+ mice of the C57Bl/6 strain was that the body weight of the GPR17 -/- mice was lower than that of the GPR17 +/+ mice when the mice were fed on a standard chow diet. We propose that the absence of GPR17 raises sympathetic activity in mice of the 129 strain in response to a low plasma fuel supply, and that the consequent loss of body fat is partly mitigated by increased energy intake.

Efficacy Comparison of Different Acupuncture Treatments for Hot Flashes: A Systematic Review with Network Meta-Analysis

The objective of this study was to conduct a systematic review and network meta-analysis to evaluate and compare the effectiveness of various types of acupuncture for menopausal hot flashes (HF). Randomized controlled trials (RCTs) were retrieved from 8 electronic databases, and the risk of bias was evaluated for the included studies. Pairwise meta-analysis and network meta-analysis were performed using Review Manager and R software for indirect comparison and ranking, respectively. In total, 23 RCTs (2,302 patients) were eligible for systematic review, of which 10 were included in network meta-analysis. Network meta-analysis showed manual acupuncture (MA) had the highest probability of reducing HF frequency and severity, followed by sham acupuncture (SA), electroacupuncture, usual care, or no treatment; furthermore, warm acupuncture significantly improved menopause-specific quality of life compared with MA or electroacupuncture. Compared with hormone replacement therapy, acupuncture had less efficacy in reducing HF frequency but enhanced menopause-specific quality of life. There was no significant difference between MA and SA in mitigating HF. The existing evidence showed that MA could be used for alleviating menopausal HF. However, it is recommended that more high-quality RCTs should be performed.

Mice as experimental models for human physiology: when several degrees in housing temperature matter

Standfirst: Some “species differences” between mouse and human can be diminished simply by housing mice at warmer temperatures. Failure to strategically turn up the thermostat may undermine translation of findings in mice into insights on human metabolic diseases.

Genes, Environments, and Phenotypic Plasticity in Immunology

For most of its history, immunology has sought to control environmental variation to establish genetic causality. As with all biological traits though, variation among individuals arises by three broad pathways: genetic (G), environmental (E), and the interactive between the two (GxE); and immunity is no different. Here, we review the value of applying the evolutionary frameworks of phenotypic plasticity and reaction norms to immunology. Because standardized laboratory environments are vastly different from the conditions under which populations evolved, we hypothesize that immunology might presently be missing important phenotypic variation and even focusing on dysregulated molecular and cellular processes. Modest adjustments to study designs could make model organism immunology more productive, reproducible, and reflective of human physiology.