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Although parenting responsibilities are correlated with gender disparities in professional development and salary, the nature of parental challenges is not well characterized. The aims of this study were to (1) illuminate faculty physicians' experiences with parenting and (2) identify system challenges and opportunities for improvement.In October 2019, a survey about parenting was sent to all physician faculty at a large Midwest academic medical center. Qualitative analysis of free-text response to the survey item "is there anything you wish to share about your experience of pregnancy or parenting as a physician" was performed. Themes were inductively identified and developed from the responses in a team-based iterative approach.Of 2069 total physician faculty, 1085 (52.4%) responded to the survey and 253 (23%) of the respondents provided free-text comments. From these comments, the authors identified three themes as sources of challenges for physician parents: operational constraints, gender biases, and nontraditional or nonheteronormative family structures. Operational factors pertained to lack of scheduling flexibility, childcare challenges, lactation, colleague coverage, and transparency of policies. Responses indicated that gender biases are encountered by all genders, and expectations built on assumptions of "traditional" gender roles and family structure are problematic for many physician parents.Addressing the challenges and opportunities identified in the study is critical to building a more supportive institutional culture around parenting and to increase gender parity in academic medicine.

Obesity impairs host defense against Klebsiella pneumoniae, but responsible mechanisms are incompletely understood. To determine the impact of diet-induced obesity on pulmonary host defense against K. pneumoniae, we fed 6-wk-old male C57BL/6j mice a normal diet (ND) or high-fat diet (HFD) (13% vs. 60% fat, respectively) for 16 wk. Mice were intratracheally infected with Klebsiella, assayed at 24 or 48 h for bacterial colony-forming units, lung cytokines, and leukocytes from alveolar spaces, lung parenchyma, and gonadal adipose tissue were assessed using flow cytometry. Neutrophils from uninfected mice were cultured with and without 2-deoxy-d-glucose (2-DG) and assessed for phagocytosis, killing, reactive oxygen intermediates (ROI), transport of 2-DG, and glucose transporter (GLUT1–4) transcripts, and protein expression of GLUT1 and GLUT3. HFD mice had higher lung and splenic bacterial burdens. In HFD mice, baseline lung homogenate concentrations of IL-1β, IL-6, IL-17, IFN-γ, CXCL2, and TNF-α were reduced relative to ND mice, but following infection were greater for IL-6, CCL2, CXCL2, and IL-1β (24 h only). Despite equivalent lung homogenate leukocytes, HFD mice had fewer intraalveolar neutrophils. HFD neutrophils exhibited decreased Klebsiella phagocytosis and killing and reduced ROI to heat-killed Klebsiella in vitro. 2-DG transport was lower in HFD neutrophils, with reduced GLUT1 and GLUT3 transcripts and protein (GLUT3 only). Blocking glycolysis with 2-DG impaired bacterial killing and ROI production in neutrophils from mice fed ND but not HFD. Diet-induced obesity impairs pulmonary Klebsiella clearance and augments blood dissemination by reducing neutrophil killing and ROI due to impaired glucose transport.

Understanding how differences in animal husbandry practices affect the reproducibility of research results is critical. We sought to understand how different beddings might influence dietary obesity studies. We compared the effects of paper and corncob bedding on weight gain, metabolism, and gut microbiome (GM) of mice fed a high-fat diet (HFD) or a normal diet (ND) and evaluated effects on fecal and cecal microbiomes collected from these cohorts after euthanasia. Male C57BL/6J mice at 5 wk age were allowed to acclimate to the facility and the assigned bedding for one week before being placed on HFD or remaining on the ND for 12 wk. Fecal pellets and cecal samples were collected and frozen for batched 16S sequencing. Mice had similar body weight, visceral gonadal white adipose tissue (GWAT), subcutaneous inguinal white adipose tissue (IWAT), liver and spleen weights and metabolic changes regardless of the bedding type. Baseline microbiota differences were detected one week after bedding assignment. After 12 wk, the GM showed significant differences depending on both bedding and diet. The effects of the bedding were not significantly different between endpoint fecal and cecal GM, despite the inherent differences in microbiota in fecal and cecal samples. A correlation was detected between diet and the relative abundance of Bacteroidetes and Verrucomicrobia: Akkermansia. In conclusion, this study demonstrates the importance of considering bedding type when performing dietary experiments.

Insulin receptor (IR) expression on the T cell surface can indicate an activated state; however, the IR is also chemotactic, enabling T cells with high IR expression to physically move toward insulin. In humans with type 1 diabetes (T1D) and the NOD mouse model, a T cell–mediated autoimmune destruction of insulin-producing pancreatic β cells occurs. In previous work, when purified IR+ and IR− T cells were sorted from diabetic NOD mice and transferred into irradiated nondiabetic NOD mice, only those that received IR+ T cells developed insulitis and diabetes. In this study, peripheral blood samples from individuals with T1D (new onset to 14 y of duration), relatives at high-risk for T1D, defined by positivity for islet autoantibodies, and healthy controls were examined for frequency of IR+ T cells. High-risk individuals had significantly higher numbers of IR+ T cells as compared with those with T1D (p < 0.01) and controls (p < 0.001); however, the percentage of IR+ T cells in circulation did not differ significantly between T1D and control subjects. With the hypothesis that IR+ T cells traffic to the pancreas in T1D, we developed a (to our knowledge) novel mouse model exhibiting a FLAG-tagged mouse IR on T cells on the C57BL/6 background, which is not susceptible to developing T1D. Interestingly, these C57BL/6-CD3FLAGmIR/mfm mice showed evidence of increased IR+ T cell trafficking into the islets compared with C57BL/6 controls (p < 0.001). This transgenic animal model provides a (to our knowledge) novel platform for investigating the influence of IR expression on T cell trafficking and the development of insulitis.

Identifying children with insulin resistance (IR) is difficult due to insulin assay reliability/reproducibility. We examined if the triglyceride/high-density lipoprotein ratio (TG/HDL) can identify children with IR and if it is important to use age- & sex-specific cutoffs. In a representative sample of 3,464 US adolescents 12-18 yrs participating in NHANES (2003-2020) , we calculated the fasting TG/HDL ratio & homeostasis model assessment-insulin resistance level (HOMA-IR) . We established age- & sex-specific & universal percentiles (10th, 25th, 50th, 75th, 95th) for TG/HDL ratio based on a subset of normal weight adolescents; IR was defined as having a HOMA-IR >4.39. We created receiver operating characteristic (ROC) curves predicting IR comparing age- & sex-specific, universal TG/HDL ratios, and raw TG/HDL cutpoints. Half were female, 14% were black, 13% were Mexican-American, and 24% had IR. AUC was similar for age-,sex-specific (0.69 (SE 0.01)) , universal (0.69 (SE 0.01)) percentiles and raw TG/HDL ratios (0.69 (SE 0.01)) (p=0.22) . Age and sex cutoffs did not provide further discrimination for identifying adolescents with IR. A universal TG/HDL ratio cutoff of 1.0 conferred a sensitivity of 84% and specificity of 42%. A TG/HDL ratio of 1.0 may be a reasonable test cutoff for identifying adolescents with IR, given that higher detection rates may improve identification of high risk children. Disclosure D.Eng: None. B.Gregg: None. K.Singer: None. J.M.Lee: Advisory Panel; GoodRx, Consultant; Tandem Diabetes Care, Inc. Funding Caswell Diabetes Institute at the University of Michigan

Obesity-induced inflammation is a risk factor for metabolic impairment leading to diabetes and cardiovascular disease. We, and others, have shown that sex differences exist in adipose tissue (AT) and myeloid inflammatory responses to high-fat diet (HFD) and lipolysis. However, the causal cellular mechanisms behind this sexual dimorphism are not well defined. Our objective was to investigate sex differences in lipid storage and metabolism that drive sexually dimorphic inflammatory responses. C57Bl/6J mice were fed a normal diet or 60%kcal%fat (HFD) for 16 weeks. AT macrophages (ATMs) were sorted for RNA sequencing. Animals were gonadectomized (GX) prior to starting HFD and gonadal white AT (GWAT) was collected for lipidomics. To directly model androgen receptor (AR) activation, GX mice were given dihydrotestosterone (DHT) to study AR-specific effects. RNA sequencing identified upregulated genes (Lpl, Ctsb, and Cd36) linked to a metabolically-activated macrophage only in male HFD ATMs. Furthermore, pathways associated with mitochondrial depolarization and fatty acid (FA) metabolism differed significantly by sex. GWAT lipidomics identified shifts in lipid species both by sex and hormone status, and differences were also observed in acylcarnitines and saturation of ceramide species that are implicated in inflammation. In addition, males showed elevated levels of key precursor free FAs (palmitic, linoleic, and arachidonic acid) when compared to female and GX mice. DHT treatment did not completely mimic male pro-inflammatory responses but induced GWAT crown-like structures in both sexes. DHT failed to upregulate inflammatory markers (Il6 and Mcp1) but showed impaired expression of adipogenic genes (Pparg and Pgc1α) in GX mice. Altogether, our data suggest there are sex-specific alterations in GWAT lipid storage and metabolism that may drive sexually dimorphic ATM polarization, which is only partially reversed by AR activation. Disclosure R. Mohan: None. M. Varghese: None. S. Abrishami: None. K. Singer: None. Funding National Institutes of Health - NIDDK (R01DK115583)

Objective Weight regain after weight loss is common, and there is evidence to suggest negative effects on health because of weight cycling. This study sought to investigate the impact of weight regain in formerly obese mice on adipose tissue architecture and stromal cell function. Methods A diet-switch model was employed for obesity induction, weight loss, and weight regain in mice. Flow cytometry quantified adipose tissue leukocytes in adipose tissue. Liver and adipose tissue depots were compared to determine tissue-specific effects of weight cycling. Results Epididymal white adipose tissue of formerly obese mice failed to expand in response to repeat exposure to high-fat diet and retained elevated numbers of macrophages and T cells. Weight regain was associated with disproportionally elevated liver mass, hepatic triglyceride content, serum insulin concentration, and serum transaminase concentration. These effects occurred despite an extended 6-month weight loss cycle and they demonstrate that formerly obese mice maintain durable alterations in their physiological response to weight regain. Conditioned media from epididymal adipose tissue of formerly obese mice inhibited adipogenesis of 3T3-L1 preadipocytes, suggesting a potential mechanism to explain failed epididymal adipose tissue expansion during weight regain. Conclusions Metabolic abnormalities related to defects in adipose tissue expansion and ongoing dysfunction manifest in formerly obese mice during weight regain.

BM adipocytes (BMAd) are a unique cell population derived from BM mesenchymal progenitors and marrow adipogenic lineage precursors. Although they have long been considered to be a space filler within bone cavities, recent studies have revealed important physiological roles in hematopoiesis and bone metabolism. To date, the approaches used to study BMAd function have been confounded by contributions by nonmarrow adipocytes or by BM stromal cells. To address this gap in the field, we have developed a BMAd-specific Cre mouse model to deplete BMAds by expression of diphtheria toxin A (DTA) or by deletion of peroxisome proliferator-activated receptor gamma (Pparg). We found that DTA-induced loss of BMAds results in decreased hematopoietic stem and progenitor cell numbers and increased bone mass in BMAd-enriched locations, including the distal tibiae and caudal vertebrae. Elevated bone mass appears to be secondary to enhanced endosteal bone formation, suggesting a local effect caused by depletion of BMAd. Augmented bone formation with BMAd depletion protects mice from bone loss induced by caloric restriction or ovariectomy, and it facilitates the bone-healing process after fracture. Finally, ablation of Pparg also reduces BMAd numbers and largely recapitulates high-bone mass phenotypes observed with DTA-induced BMAd depletion.

SummaryTo investigate roles for bone marrow adipocyte (BMAd) lipolysis in bone homeostasis, we created a BMAd-specific Cre mouse model in which we knocked out adipose triglyceride lipase (ATGL, Pnpla2). BMAd-Pnpla2-/- mice have impaired BMAd lipolysis, and increased size and number of BMAds at baseline. Although energy from BMAd lipid stores is largely dispensable when mice are fed ad libitum, BMAd lipolysis is necessary to maintain myelopoiesis and bone mass under caloric restriction. BMAd-specific Pnpla2 deficiency compounds the effects of caloric restriction on loss of trabecular bone, likely due to impaired osteoblast expression of collagen genes and reduced osteoid synthesis. RNA sequencing analysis of bone marrow adipose tissue reveals that caloric restriction induces dramatic elevations in extracellular matrix organization and skeletal development genes, and energy from BMAd is required for these adaptations. BMAd-derived energy supply is also required for bone regeneration upon injury, and maintenance of bone mass with cold exposure.

The risk of obesity in adulthood is subject to programming in the womb. Maternal obesity contributes to programming of obesity and metabolic disease risk in the adult offspring. With the increasing prevalence of obesity in women of reproductive age there is a need to understand the ramifications of maternal high-fat diet (HFD) during pregnancy on offspring’s metabolic heath trajectory. In the present study, we determined the long-term metabolic outcomes on adult male and female offspring of dams fed with HFD during pregnancy. C57BL/6J dams were fed either Ctrl or 60% Kcal HFD for 4 weeks before and throughout pregnancy, and we tested glucose homeostasis in the adult offspring. Both Ctrl and HFD-dams displayed increased weight during pregnancy, but HFD-dams gained more weight than Ctrl-dams. Litter size and offspring birthweight were not different between HFD-dams or Ctrl-dams. A significant reduction in random blood glucose was evident in newborns from HFD-dams compared to Ctrl-dams. Islet morphology and alpha-cell fraction were normal but a reduction in beta-cell fraction was observed in newborns from HFD-dams compared to Ctrl-dams. During adulthood, male offspring of HFD-dams displayed comparable glucose tolerance under normal chow. Male offspring re-challenged with HFD displayed glucose intolerance transiently. Adult female offspring of HFD-dams demonstrated normal glucose tolerance but displayed increased insulin resistance relative to controls under normal chow diet. Moreover, adult female offspring of HFD-dams displayed increased insulin secretion in response to high-glucose treatment, but beta-cell mass were comparable between groups. Together, these data show that maternal HFD at pre-conception and during gestation predisposes the female offspring to insulin resistance in adulthood.

Obesity is associated with systemic inflammation and immune cell recruitment to metabolic tissues. Sex differences have been observed where male mice challenged with high fat diet (HFD) exhibit greater adipose tissue inflammation than females demonstrating a role for sex hormones in differential inflammatory responses. Circulating monocytes that respond to dietary lipids and chemokines and produce cytokines are the primary source of recruited adipose tissue macrophages (ATMs). In this study, we investigated sexual dimorphism in biological pathways in HFD-fed ATMs from male and female mice by RNA-seq. We also conducted chemotaxis assays to investigate sex differences in the migration of monocytes isolated from bone marrow from male and female mice toward a dietary saturated lipid — palmitate (PA), and a chemokine — monocyte chemoattractant protein 1 (MCP1), factors known to stimulate myeloid cells in obesity. ATM RNA-Seq demonstrated sex differences of both metabolic and inflammatory activation, including pathways for chemokine signaling and leukocyte trans-endothelial migration. In vivo monocyte transfer studies demonstrated that male monocytes traffic to female adipose tissue to generate ATMs more readily. In chemotaxis assays, lean male monocytes migrated in greater numbers than females toward PA and MCP1. With short-term HFD, male and female monocytes migrated similarly, but in chronic HFD, male monocytes showed greater migration than females upon PA and MCP1 stimulation. Studies with monocytes from toll-like receptor 4 knockout mice (Tlr4-/-) demonstrated that both males and females showed decreased migration than WT in response to PA and MCP1 implying a role for TLR4 in monocyte influx in response to meta-inflammation. Overall, these data demonstrate the role of sexual dimorphism in monocyte recruitment and response to metabolic stimuli that may influence meta-inflammation in obesity.

Aging, like obesity, is associated with metabolic and inflammatory alterations within adipose tissue in older individuals. Younger females are protected from adipose inflammation, but older post-menopausal females exhibit exaggerated visceral adiposity correlated with increased disease risk. Obesity accelerates the onset and progression of age-associated diseases, but it is unclear if aging and obesity drive adipose tissue dysfunction in a sexually dimorphic fashion. We investigated adipose tissue metabolism and inflammation in a diet-induced obesity model in young and old mice. We identified age related sex differences in adipose tissue macrophages (ATMs), fibrosis and lipid metabolism in male and female visceral fat depot (GWAT). Although aging normalized body weights between the sexes, females remained protected from proinflammatory ATMs and stimulated lipolysis failed to adversely affect the inflammatory state even with obesity. Older obese males had augmented CD11c+ ATMs and higher insulin levels, while females showed increased visceral adiposity and exaggerated Pparγ, and Pgc1α expression. Obesity in aging demonstrated similar expression of GWAT p53, p16, p21, Timp1 and Tgfβ1 in both sexes. Our studies suggest that even with aging, female GWAT shows an attenuated inflammatory response compared to males due to an efficient oxidative metabolism combined with an active tissue remodeling state.

Bariatric surgeries are integral to the management of obesity and its metabolic complications. However, these surgeries cause bone loss and increase fracture risk through poorly understood mechanisms. In a mouse model, vertical sleeve gastrectomy (VSG) caused trabecular and cortical bone loss that was independent of sex, body weight, and diet, and this loss was characterized by impaired osteoid mineralization and bone formation. VSG had a profound effect on the bone marrow niche, with rapid loss of marrow adipose tissue, and expansion of myeloid cellularity, leading to increased circulating neutrophils. Following VSG, circulating granulocyte-colony stimulating factor (G-CSF) was increased in mice, and was transiently elevated in a longitudinal study of humans. Elevation of G-CSF was found to recapitulate many effects of VSG on bone and the marrow niche. In addition to stimulatory effects of G-CSF on myelopoiesis, endogenous G-CSF suppressed development of marrow adipocytes and hindered accrual of peak cortical and trabecular bone. Effects of VSG on induction of neutrophils and depletion of marrow adiposity were reduced in mice deficient for G-CSF; however, bone mass was not influenced. Although not a primary mechanism for bone loss with VSG, G-CSF plays an intermediary role for effects of VSG on the bone marrow niche.

Myeloid cells are critical for orchestrating regulated inflammation during wound healing. TLRs, particularly TLR4, and its downstream-signaling MyD88 pathway play an important role in regulating myeloid-mediated inflammation. Because an initial inflammatory phase is vital for tissue repair, we investigated the role of TLR4-regulated, myeloid-mediated inflammation in wound healing. In a cutaneous tissue injury murine model, we found that TLR4 expression is dynamic in wound myeloid cells during the course of normal wound healing. We identified that changes in myeloid TLR4 during tissue repair correlated with increased expression of the histone methyltransferase, mixed-lineage leukemia 1 (MLL1), which specifically trimethylates the histone 3 lysine 4 (H3K4me3) position of the TLR4 promoter. Furthermore, we used a myeloid-specific Mll1 knockout (Mll1f/fLyz2Cre+) to determine MLL1 drives Tlr4 expression during wound healing. To understand the critical role of myeloid-specific TLR4 signaling, we used mice deficient in Tlr4 (Tlr4−/−), Myd88 (Myd88−/−), and myeloid-specific Tlr4 (Tlr4f/fLyz2Cre+) to demonstrate delayed wound healing at early time points postinjury. Furthermore, in vivo wound myeloid cells isolated from Tlr4−/− and Myd88−/− wounds demonstrated decreased inflammatory cytokine production. Importantly, adoptive transfer of monocyte/macrophages from wild-type mice trafficked to wounds with restoration of normal healing and myeloid cell function in Tlr4-deficient mice. These results define a role for myeloid-specific, MyD88-dependent TLR4 signaling in the inflammatory response following cutaneous tissue injury and suggest that MLL1 regulates TLR4 expression in wound myeloid cells.

Nearly 80% of patients that receive bariatric surgery are women, yet mechanistic preclinical studies have focused on males. The goal of this study was to determine the metabolic impact of diet- and surgery-induced weight loss in males, females, and ovariectomized females. All mice were fed a 60% high-fat diet (HFD) before undergoing either vertical sleeve gastrectomy (VSG) or sham surgery. Mice either remained on an HFD or were switched to a standard chow diet postsurgically. When maintained on an HFD, males and females decreased fat mass and improved oral glucose tolerance after VSG. After dietary intervention, additional adiposity was lost in both surgical groups. Ovariectomized females showed a blunted decrease in fat mass on an HFD, but lost significant adiposity after dietary intervention. Energy expenditure was impacted by dietary and not surgical intervention across all groups. Males decreased hepatic triglyceride levels after VSG, which was further decreased after dietary intervention. Intact and ovariectomized females had a blunted decrease in hepatic triglycerides after VSG, but a significant decrease after dietary intervention. The more pronounced effect of VSG on hepatic lipids in males is strongly associated with changes in hepatic expression of genes and microRNAs previously linked to hepatic lipid regulation and systemic energy homeostasis. These data highlight the importance of postsurgical diet on metabolic outcomes across sexes. Furthermore, these data suggest the impact of VSG on hepatic triglycerides is diet-dependent in females and support the hypothesis that males and females achieve similar metabolic outcome, at least within the liver, via distinct mechanisms. NEW & NOTEWORTHY These data highlight the interaction of postsurgical diet after bariatric surgery on metabolic outcomes across sexes. These data suggest the impact of VSG on hepatic triglycerides is diet-dependent in females and support the hypothesis that males and females achieve similar metabolic outcome, at least within the liver, via distinct mechanisms.

Obesity and obesity-related diseases like type 2 diabetes (T2D) are prominent global health issues; therefore, there is a need to better understand the mechanisms underlying these conditions. The onset of obesity is characterized by accumulation of proinflammatory cells, including Ly6chi monocytes (which differentiate into proinflammatory macrophages) and neutrophils, in metabolic tissues. This shift toward chronic, low-grade inflammation is an obese-state hallmark and highly linked to metabolic disorders and other obesity comorbidities. The mechanisms that induce and maintain increased inflammatory myelopoiesis are of great interest, with a recent focus on how obesity affects more primitive hematopoietic cells. The hematopoietic system is constantly replenished by proper regulation of hematopoietic stem and progenitor (HSPC) pools in the BM. While early research suggests that chronic obesity promotes expansion of myeloid-skewed HSPCs, the involvement of the hematopoietic stem cell (HSC) niche in regulating obesity-induced myelopoiesis remains undefined. In this review, we explore the role of the multicellular HSC niche in hematopoiesis and inflammation, and the potential contribution of this niche to the hematopoietic response to obesity. This review further aims to summarize the potential HSC niche involvement as a target of obesity-induced inflammation and a driver of obesity-induced myelopoiesis.

Obesity is a major global public health concern. Worldwide, 39% of the population is overweight and 13% of the population is obese. Obesity contributes to many diseases, such as heart disease, stroke, some cancers, and notably, type 2 diabetes (T2D). Although T2D itself is a non-communicable disease, many patients with diabetes are more susceptible to microbial infections and exhibit a higher burden of disease. Although obese animals have an increased production of myeloid cells, previous work from our labs has shown that a failure to heal diabetic wounds corresponds to elevated levels of prostaglandin E2 (PGE2) in the inflammatory macrophages that are recruited to the wound. Furthermore, past studies from our lab have demonstrated that PGE2 signaling can impair the innate immune functions of macrophages. Therefore, we hypothesized that diabetic obese mice would be more susceptible to a respiratory Pseudomonas aeruginosa strain PA01 infection due to impaired function of lung resident and recruited macrophages. Preliminary studies demonstrate that obese diabetic mice do have an increased P. aeruginosa burden in the lung 24 hours after infection. Additionally, we have determined that naïve obese diabetic mice have an increase in lung neutrophils compared to lean mice, however, after infection with P. aeruginosa, these mice have a trend of decreased neutrophil recruitment. Additionally, functional assays show that macrophages and neutrophils from obese diabetic mice have a defect in killing P. aeruginosa. These observations suggest that obese diabetic mice have not only a defect in innate immune cell recruitment, but also a defect in innate immune cell function during bacterial pneumonia. Supported by grants from NIH (T32 AI007528-21)

We describe a novel gold-templating method for fabricating stable, biodegradable, bile salt microparticles with controlled geometry., Bile acids are proposed as therapeutic agents for various diseases, including liver diseases and obesity. However, oral or subcutaneous administration of a solubilized version of these drugs has limited efficacy and imposes unwanted side effects. Here, we describe a gold-templating method for fabricating stable, bile salt—cholate or deoxycholate—microparticles. The gold ions’ reduction at the oil-water interface in a double emulsion solvent evaporation process enables a gold–bile salt interaction and the formation of bile salt particles. We demonstrate that composite microparticles release cholate/deoxycholate into solution via a surface erosion process. We illustrate these particles’ capability to lyse adipocytes, both in vitro and in vivo, with minimal side effects, contrary to the Food and Drug Administration–approved salt solution that leads to severe inflammation and ulceration. Overall, particle-based cholate/deoxycholate opens opportunities for localized delivery of these salts, improving efficacy while minimizing side effects associated with oral and subcutaneous use.

Insulin bolus calculators have proven effective in improving glycemia and patient safety. Insulin calculators are increasingly being implemented for inpatient hospital care. Multidisciplinary teams are often involved in the design and review of the efficacy and utilization for these calculators. At times, unintended consequences and benefits of utilization are found on review. Integration of our insulin calculator into our electronic health record system was a multidisciplinary effort. During implementation, several obstacles to effective care were identified and are discussed in the following manuscript. We describe the barriers to utilization and potential pitfalls in clinical integration. We further describe benefits in patient education, time of insulin administration versus meal delivery, variations in insulin bolus for ketone correction, variation in care, and maximum bolus administration. Sharing lessons learned from experiences using electronic insulin calculator order sets will further our goals of improved patient care in the hospital setting.

The coronavirus disease 2019 (COVID-19) pandemic has forced us to consider the physiologic role of obesity in the response to infectious disease. There are significant disparities in morbidity and mortality by sex, weight, and diabetes status. Numerous endocrine changes might drive these varied responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, including hormone and immune mediators, hyperglycemia, leukocyte responses, cytokine secretion, and tissue dysfunction. Studies of patients with severe COVID-19 disease have revealed the importance of innate immune responses in driving immunopathology and tissue injury. In this review we will describe the impact of the metabolically induced inflammation (meta-inflammation) that characterizes obesity on innate immunity. We consider that obesity-driven dysregulation of innate immune responses may drive organ injury in the development of severe COVID-19 and impair viral clearance.

Adipose tissue pathology in obese patients often features impaired adipogenesis, angiogenesis, and chronic low-grade inflammation, all of which are regulated in large part by adipose tissue stromal vascular cells [SVC; i.e., non-adipocyte cells within adipose tissue including preadipocytes, endothelial cells (ECs), and immune cells]. Exercise is known to increase subcutaneous adipose tissue lipolysis, but the impact of exercise on SVCs in adipose tissue has not been explored. The purpose of this study was to assess the effects of a session of exercise on preadipocyte, EC, macrophage, and T cell content in human subcutaneous adipose tissue. We collected abdominal subcutaneous adipose tissue samples from 10 obese adults (BMI 33 ± 3 kg/m2, body fat 41 ± 7%) 12 h after a 60 min acute session of endurance exercise (80 ± 3%HRpeak) vs. no acute exercise session. SVCs were isolated by collagenase digestion and stained for flow cytometry. We found that acute exercise reduced preadipocyte content (38 ± 7 vs. 30 ± 13%SVC; p = 0.04). The reduction was driven by a decrease in CD34hi preadipocytes (18 ± 5 vs. 13 ± 6%SVC; p = 0.002), a subset of preadipocytes that generates high lipolytic rate adipocytes ex vivo. Acute exercise did not alter EC content. Acute exercise also did not change total immune cell, macrophage, or T cell content, and future work should assess the effects of exercise on subpopulations of these cells. We conclude that exercise may rapidly regulate the subcutaneous adipose tissue preadipocyte pool in ways that may help attenuate the high lipolytic rates that are commonly found in obesity.

Gender inequality exists in advanced faculty and leadership positions at academic medical centers; however, despite growing awareness, how to best approach and rectify the issue is unknown. To energize the conversation on gender inequality at one academic medical center, chairs and women faculty were surveyed to identify barriers faced by women navigating their careers. A symposium with short talks to increase awareness, a panel with University leaders to discuss issues and successful strategies to overcome gaps, and focus groups to delve further into key areas that underlie inequity through an active café style format were planned and implemented. This multifaceted approach resulted in a wealth of knowledge. The symposium and panel highlighted important relevant issues and offered personal strategies for successful career advancement, while the focus group discussions further identified barriers and inspired ongoing efforts across departments and novel approaches to overcome three key issues (work-life integration, deliberate promotion of mentor/sponsor relationships, and overcoming unconscious bias) identified through the initial surveys. Compiled data were then disseminated to participants and University leaders to enhance awareness of available programs and prompt action in critical areas lacking support. Overall, the approach indicated that securing support from leaders and the academic community alike are pertinent to emphasize actions needed to overcome issues affecting women in academic medicine. Moreover, bringing leaders and faculty together for an informational session and brainstorming appears to energize the conversation. Such efforts can ultimately instill change and establish an inclusive environment where all members of the academic medicine community can thrive.

Obesity-induced chronic inflammation is associated with metabolic disease. Results from mouse models utilizing a high-fat diet (HFD) have indicated that an increase in activated macrophages, including CD11c+ adipose tissue macrophages (ATMs), contributes to insulin resistance. Obesity primes myeloid cell production from hematopoietic stem cells (HSCs) and Toll-like receptor 4 (TLR4), and the downstream TIR domain-containing adapter protein-inducing interferon-β (TRIF)- and MyD88-mediated pathways regulate production of similar myeloid cells after lipopolysaccharide stimulation. However, the role of these pathways in HFD-induced myelopoiesis is unknown. We hypothesized that saturated fatty acids and HFD alter myelopoiesis by activating TLR4 pathways in HSCs, differentially producing pro-inflammatory CD11c+ myeloid cells that contribute to obesity-induced metabolic disease. Results from reciprocal bone marrow transplants (BMTs) with Tlr4-/- and WT mice indicated that TLR4 is required for HFD-induced myelopoiesis and production of CD11c+ ATMs. Experiments with homozygous knockouts of Irakm (encoding a suppressor of MyD88 inactivation) and Trif in competitive BMTs revealed that MyD88 is required for HFD expansion of granulocyte macrophage progenitors and that Trif is required for pregranulocyte macrophage progenitor expansion. A comparison of WT, Tlr4-/-, Myd88-/-, and Trif-/- mice on HFD demonstrated that TLR4 plays a role in the production of CD11c+ ATMs, and both Myd88-/- and Trif-/- mice produced fewer ATMs than WT mice. Moreover, HFD-induced TLR4 activation inhibited macrophage proliferation, leading to greater accumulation of recruited CD11c+ ATMs. Our results indicate that HFD potentiates TLR4 and both its MyD88- and TRIF-mediated downstream pathways within progenitors and adipose tissue and leads to macrophage polarization.

Obesity-related changes in adipose tissue leukocytes, in particular adipose tissue macrophages (ATMs) and dendritic cells (ATDCs), are implicated in metabolic inflammation, insulin resistance, and altered regulation of adipocyte function. We evaluated stromal cell and white adipose tissue (WAT) expansion dynamics with high fat diet (HFD) feeding for 3–56 days, quantifying ATMs, ATDCs, endothelial cells (ECs), and preadipocytes (PAs) in visceral epididymal WAT and subcutaneous inguinal WAT. To better understand mechanisms of the early response to obesity, we evaluated ATM proliferation and lipid accumulation. ATMs, ATDCs, and ECs increased with rapid WAT expansion, with ATMs derived primarily from a CCR2-independent resident population. WAT expansion stimulated proliferation in resident ATMs and ECs, but not CD11c+ ATMs or ATDCs. ATM proliferation was unperturbed in Csf2- and Rag1-deficient mice with WAT expansion. Additionally, ATM apoptosis decreased with WAT expansion, and proliferation and apoptosis reverted to baseline with weight loss. Adipocytes reached maximal hypertrophy at 28 days of HFD, coinciding with a plateau in resident ATM accumulation and the appearance of lipid-laden CD11c+ ATMs in visceral epididymal WAT. ATM increases were proportional to tissue expansion and adipocyte hypertrophy, supporting adipocyte-mediated regulation of resident ATMs. The appearance of lipid-laden CD11c+ ATMs at peak adipocyte size supports a role in responding to ectopic lipid accumulation within adipose tissue. In contrast, ATDCs increase independently of proliferation and may be derived from circulating precursors. These changes precede and establish the setting in which large-scale adipose tissue infiltration of CD11c+ ATMs, inflammation, and adipose tissue dysfunction contributes to insulin resistance.

Men have a statistically higher risk of metabolic and cardiovascular disease than premenopausal women, but the mechanisms mediating these differences are elusive. Chronic inflammation during obesity contributes to disease risk and is significantly more robust in males. Prior work demonstrated that compared with obese males, obese females have reduced proinflammatory adipose tissue macrophages (ATMs). Given the paucity of data on how sex hormones contribute to macrophage responses in obesity, we sought to understand the role of sex hormones in promoting obesity-induced myeloid inflammation. We used gonadectomy, estrogen receptor–deficient alpha chimeras, and androgen-insensitive mice to model sex hormone deficiency. These models were evaluated in diet-induced obesity conditions (high-fat diet [HFD]) and in vitro myeloid assays. We found that ovariectomy increased weight gain and adiposity. Ovariectomized females had increased ATMs and bone marrow myeloid colonies compared with sham-gonadectomized females. In addition, castrated males exposed to HFD had improved glucose tolerance, insulin sensitivity, and adiposity with fewer Ly6chi monocytes and bone marrow myeloid colonies compared with sham-gonadectomized males, although local adipose inflammation was enhanced. Similar findings were observed in androgen-insensitive mice; however, these mice had fewer CD11c+ ATMs, implying a developmental role for androgens in myelopoiesis and adipose inflammation. We concluded that gonadectomy results in convergence of metabolic and inflammatory responses to HFD between the sexes, and that myeloid estrogen receptor alpha contributes minimally to diet-induced inflammatory responses, whereas loss of androgen-receptor signaling improves metabolic and inflammatory outcomes. These studies demonstrate that sex hormones play a critical role in sex differences in obesity, metabolic dysfunction, and myeloid inflammation.

Age associated chronic inflammation is a major contributor to diseases with advancing age. Adipose tissue function is at the nexus of processes contributing to age-related metabolic disease and mediating longevity. Hormonal fluctuations in aging potentially regulate age-associated visceral adiposity and metabolic dysfunction. Visceral adiposity in aging is linked to aberrant adipogenesis, insulin resistance, lipotoxicity and altered adipokine secretion. Age-related inflammatory phenomena depict sex differences in macrophage polarization, changes in T and B cell numbers, and types of dendritic cells. Sex differences are also observed in adipose tissue remodeling and cellular senescence suggesting a role for sex steroid hormones in the regulation of the adipose tissue microenvironment. It is crucial to investigate sex differences in aging clinical outcomes to identify and better understand physiology in at-risk individuals. Early interventions aimed at targets involved in adipose tissue adipogenesis, remodeling and inflammation in aging could facilitate a profound impact on health span and overcome age-related functional decline.

Summary Background: Insulin dosing in hospitalized pediatric patients is challenging and requires dosing to be matched with the specific clinical and nutritional circumstances. We implemented a customized subcutaneous insulin bolus dose calculator tool integrated with the electronic health record to improve patient care. Here we describe this tool, its utilization and safety, and assess user satisfaction and perceptions of the tool. Methods: Blood glucose results for all patients who received insulin with and without the calculator tool were compared to assess safety. To assess user perceptions and satisfaction, a survey was sent to all identified users who interacted with the tool during the period from May 2015 to the end of November 2015. Survey responses were summarized, mean user satisfaction calculated, and correlation of Likert scale items with overall satisfaction assessed. Results: Hypoglycemia rates (2.2% and 2.9%, p = 0.17) and severe hypoglycemia rates (0.04% and 0.1%, p = 0.21) were similar for the groups that received insulin with and without the calculator tool. Overall satisfaction for all survey respondents was high (4.05, SD = 0.83). Physicians indicated a slightly higher satisfaction than nurses (4.33 versus 3.94, p = 0.04). User agreement with improvement of quality of care showed the highest correlation with overall satisfaction (r = 0.80, 95% CI 0.7 –0.87). Conclusion: Implementation of an insulin calculator tool streamlined ordering and administration of insulin in a pediatric academic institution while maintaining patient safety. Users indicated high overall satisfaction with the tool. Citation: Ateya MB, Aiyagari R, Moran C, Singer K. .:Insulin bolus calculator in a pediatric hospital: Safety and user perceptions. Appl Clin Inform 2017; 8: 529–540 https://doi.org/10.4338/ACI-2016-11-RA-0187

In obesity, high levels of saturated fatty acids (SFAs) contribute to adipose tissue inflammation and dysfunction. Obesity-induced macrophage infiltration leads to insulin resistance, but the adipocyte itself may play a role in generating the inflammatory milieu. Given our recent findings of the role of TLR4 in myeloid biasing in obesity, we next investigated the role of TLR4 in adipocyte generated inflammatory responses to SFAs and lipopolysaccharides. We used WT and Tlr4−/- ear mesenchymal stem cell derived adipocytes (EMSC Ad) and bone marrow dendritic cells (BMDCs) to evaluate cell specific responses. Our work demonstrates a role for TLR4 in adipocyte- immune cell crosstalk and that SFA derived metabolites from adipocytes may induce proinflammatory stimulation of immune cells in a TLR4 independent manner.

With the increasing prevalence of obesity in women of reproductive age there is a need to understand the ramifications of this on offspring. The purpose of this study is to investigate the programming effects of maternal obesity during preconception and the preconception/gestational period on adiposity and adipose tissue inflammation in offspring using an animal model. Adult female C57Bl/6J mice were assigned either normal diet, high fat diet (HFD) prior to pregnancy, or HFD prior to and through pregnancy. Some offspring were maintained on normal diet while others started HFD later in life. Offspring were assessed for body composition and metabolic responses. Lipid storing tissues were evaluated for expansion and inflammation. Male offspring from the preconception group had the greatest weight gain, most subcutaneous adipose tissue, and largest liver mass when introduced to postnatal HFD. Male offspring of the preconception/gestation group had worsened glucose tolerance and an increase in resident (CD11c−) adipose tissue macrophages (ATMs) when exposed to postnatal HFD. Female offspring had no significant difference in any parameter between the diet treatment groups. In conclusion, this study demonstrates that prenatal and pregnancy windows have independent programming effects on offspring. Preconception exposure affects body composition and adiposity while gestation exposure affects metabolism and tissue immune cell phenotypes.

Prenatal testosterone (T)-treated female sheep exhibit an enhanced inflammatory and oxidative stress state in the visceral adipose tissue (VAT) but not in the subcutaneous (SAT), while surprisingly maintaining insulin sensitivity in both depots. In adult sheep, adipose tissue is predominantly composed of white adipocytes which favor lipid storage. Brown/beige adipocytes that make up the brown adipose tissue (BAT) favor lipid utilization due to thermogenic uncoupled protein 1 expression and are interspersed amidst white adipocytes, more so in epicardiac (ECAT) and perirenal (PRAT) depots. The impact of prenatal T-treatment on ECAT and PRAT depots are unknown. As BAT imparts a metabolically healthy phenotype, the depot-specific impact of prenatal T-treatment on inflammation, oxidative stress, differentiation and insulin sensitivity could be dictated by the distribution of brown adipocytes. This hypothesis was tested by assessing markers of oxidative stress, inflammation, adipocyte differentiation, fibrosis and thermogenesis in adipose depots from control and prenatal T (100 mg T propionate twice a week from days 30–90 of gestation) -treated female sheep at 21 months of age. Our results show prenatal T-treatment induces depot-specific changes in inflammation, oxidative stress state, collagen accumulation, and differentiation with changes being more pronounced in the VAT. Prenatal T-treatment also increased thermogenic gene expression in all depots indicative of increased browning with effects being more prominent in VAT and SAT. Considering that inflammatory and oxidative stress are also elevated, the increased brown adipocyte distribution is likely a compensatory response to maintain insulin sensitivity and function of organs in the proximity of respective depots.

Objective: We aimed to examine if myeloid leukocyte profiles are associated with metabolic impairment in children and adolescents with obesity, and if sex, age, or race influence this relationship.Methods: 282 children ages 8–17 were evaluated. Predictor measures were absolute neutrophil counts (ANC), absolute monocyte count, monocyte subtypes and C reactive protein (CRP). Outcome variables were waist circumference, fasting glucose and insulin, HOMA-IR, HbA1c (%) and lipid profiles. Pearson correlation coefficients were used to determine associations between predictor and outcome variables. Wilcoxon two-sample tests were used to evaluate differences by sex.Results: CRP (p < 0.0001), ANC (p < 0.0018), and classical monocytes (p = 0.05) were significantly higher in children with obesity. CRP, ANC and classical monocytes showed positive correlations with waist circumference, insulin, HOMA-IR and triglycerides. CRP was positively associated with ANC overall (p = 0.05). ANC demonstrated positive correlation with monocytes (p < 0.001). The associations between predictor and outcome variables were influenced by sex, race, and age.Conclusions: CRP and myeloid leukocyte populations, specifically classical monocytes and neutrophils associate with both body composition and metabolic parameters in children with obesity suggesting that these cells may play a critical role in metabolic impairment. Race, gender and age interactions between monocytes and metabolic parameters were significant.

Background Weight loss by surgery or lifestyle changes is strongly recommended for obese individuals to improve metabolic health, but the underlying impairments that persist from a history of obesity remain unclear. Recent investigations demonstrate a persistent inflammatory state with weight loss and bariatric surgery, but the mechanism and impact are not fully understood. Additionally, these studies have not been performed in females although women are the majority of individuals undergoing weight loss interventions. Methods The goal of this study was to determine the sex differences in metabolically induced inflammation after dietary weight loss (WL) or bariatric surgery. Following a 60% high-fat diet (HFD) for 12 weeks, C57Bl/6j mice underwent either a dietary switch to normal chow for WL or vertical sleeve gastrectomy (VSG) and were evaluated 8 weeks after intervention. WL effects on myelopoiesis were further evaluated with bone marrow chimeras. Results Both sexes had a decrease in adiposity and total weight following WL or VSG intervention. With HFD, females had very little inflammation and no further increase with WL, but males had persistent inflammation even after WL despite metabolic improvement. Interestingly, after VSG, myeloid inflammation was increased in the livers of males and to a lesser extent in females. Conclusions These studies demonstrate that regardless of sex, it is critical to assess an individuals’ history of obesity rather than just rely on current weight status in medical decision-making. There are long-lasting effects on tissue inflammation in both sexes especially with surgical weight loss. Dietary change is overall most effective to improve meta-inflammation in obese males on its own or in combination with surgical weight loss.

Obesity is a global health epidemic, closely associated with cardiovascular diseases (CVD), hypertension, type 2 diabetes, and atherosclerosis. Obese adipose tissue is a site and source for inflammation that is strongly associated with these metabolic diseases. In obese mice models, males exhibit profound adipose tissue macrophage (ATM) accumulation in gonadal white adipose tissue (GWAT) linked to insulin resistance, while females are protected even with enhanced adiposity. This dampened inflammation may directly explain reduced metabolic and cardiovascular disease in young women. However, it is not clear what metabolic and inflammatory responses occur in post-menopausal models. We hypothesized an increased inflammatory response would occur in obese older females. We challenged male and female C57Bl6/j mice to 16-24 weeks of 60% high fat diet (HFD) starting at 6 weeks of age (young) or 10 month of age (old). Animal body weights and metabolic depot (adipose and liver) weights were measured at the completion of diet challenge. Flow cytometry was used to determine ATM populations in visceral (GWAT) compared to subcutaneous inguinal WAT (IWAT). Lipolysis was stimulated with a beta3 adrenergic receptor (ADRB3) agonist CL-316, 243 and free fatty acids (FFA), glycerol, and triglyceride (TG) levels assessed in serum and liver. Obesity in young mice led to fat accumulation in GWAT and IWAT of both males and females. In old male animals, fat pads did not expand, and liver weights were as a result larger than in females. Both young and old females had reduced adipose inflammation compared to males. ADRB3 activation had no effect on adipose tissue weights but significantly increased liver weights in obese young females. Obese CL treated young and old female mice showed elevated FFA compared to levels induced in males. Lipolysis promoted appearance of crown like structures (CLS) in both obese young and old males and females, due to CD11c- ATM accumulation. Obesity during aging continues to lead to enhanced inflammation in males along with steatosis but females continue to be protected with appropriate storage of fatty acids with very little induced inflammation. Sex differences in inflammation that persist in aging demonstrate that differences in meta-inflammation may explain sex differences in metabolic and cardiovascular diseases regardless of age and need to be further explored for targeted treatment strategies.

Obesity causes dramatic proinflammatory changes in the adipose tissue immune environment, but relatively little is known regarding how this inflammation responds to weight loss (WL). To understand the mechanisms by which meta-inflammation resolves during WL, we examined adipose tissue leukocytes in mice after withdrawal of a high-fat diet. After 8 weeks of WL, mice achieved similar weights and glucose tolerance values as age-matched lean controls but showed abnormal insulin tolerance. Despite fat mass normalization, total and CD11c+ adipose tissue macrophage (ATM) content remained elevated in WL mice for up to 6 months and was associated with persistent fibrosis in adipose tissue. ATMs in formerly obese mice demonstrated a proinflammatory profile, including elevated expression of interferon-γ, tumor necrosis factor-α, and interleukin-1β. T-cell–deficient Rag1−/− mice showed a degree of ATM persistence similar to that in WT mice, but with reduced inflammatory gene expression. ATM proliferation was identified as the predominant mechanism by which ATMs are retained in adipose tissue with WL. Our study suggests that WL does not completely resolve obesity-induced ATM activation, which may contribute to the persistent adipose tissue damage and reduced insulin sensitivity observed in formerly obese mice.

It is well known in clinical and animal studies that women and men have different disease risk as well as different disease physiology. Women of reproductive age are protected from metabolic and cardiovascular disease compared with postmenopausal women and men. Most murine studies are skewed toward the use of male mice to study obesity-induced metabolic dysfunction because of similar protection in female mice. We have investigated dietary obesity in a mouse model and have directly compared inflammatory responses in males and females. In this review we will summarize what is known about sex differences in diet-induced inflammation and will summarize our data on this topic. It is clear that sex differences in high-fat diet-induced inflammatory activation are due to cell intrinsic differences in hematopoietic responses to obesogenic cues, but further research is needed to understand what leads to sexually dimorphic responses.

Background:Sepsis induces inflammation in response to infection and is a major cause of mortality and hospitalization in children. Obesity induces chronic inflammation leading to many clinical manifestations. Our understanding of the impact of obesity on diseases, such as infection and sepsis, is limited. The objective of this study was to evaluate the association of obesity with organ dysfunction, mortality, duration, and charges during among US children hospitalized with infection.Methods:Retrospective study of hospitalizations in children with infection aged 0 to 20 years, using the 2009 Kids’ Inpatient Database.Results:Of 3.4 million hospitalizations, 357 701 were for infection, 5685 of which were reported as obese children. Obese patients had higher rates of organ dysfunction (7.35% vs 5.5%, P < .01), longer hospital stays (4.1 vs 3.5 days, P < .001), and accrued higher charges (US$29 019 vs US$21 200, P < .001). In multivariable analysis, mortality did not differ by obesity status (odds ratio: 0.56, 95% confidence interval: 0.23-1.34), however severity of illness modified the association between obesity status and the other outcomes.Conclusions:While there was no difference in in-hospital mortality by obesity diagnosis, variation in organ dysfunction, hospital stay, and hospital charges according to obesity status was mediated by illness severity. Findings from this study have significant implications for targeted approaches to mitigate the burden of obesity on infection and sepsis.

Among potential contributors for the increased incidence of metabolic diseases is the developmental exposure to endocrine-disrupting chemicals such as bisphenol A (BPA). BPA is an estrogenic chemical used in a variety of consumer products. Evidence points to interactions of BPA with the prevailing environment. The aim of this study was to assess the effects of prenatal exposure to BPA on postnatal metabolic outcomes, including insulin resistance, adipose tissue distribution, adipocyte morphometry, and expression of inflammatory markers in adipose tissue as well as to assess whether postnatal overfeeding would exacerbate these effects. Findings indicate that prenatal BPA exposure leads to insulin resistance in adulthood in the first breeder cohort ( study 1), but not in the second cohort ( study 2), which is suggestive of potential differences in genetic susceptibility. BPA exposure induced adipocyte hypertrophy in the visceral fat depot without an accompanying increase in visceral fat mass or increased CD68, a marker of macrophage infiltration, in the subcutaneous fat depot. Cohens effect size analysis found the ratio of visceral to subcutanous fat depot in the prenatal BPA-treated overfed group to be higher compared with the control-overfed group. Altogether, these results suggest that exposure to BPA during fetal life at levels found in humans can program metabolic outcomes that lead to insulin resistance, a forerunner of type 2 diabetes, with postnatal obesity failing to manifest any interaction with prenatal BPA relative to insulin resistance and adipocyte hypertrophy.

This survey study compares the perceptions of male and female physician faculty members who have children regarding parenting challenges and career progression at an academic hospital.

Males are known to have profound adipose tissue macrophage (ATM) accumulation in gonadal white adipose tissue (GWAT) during obesity, whereas females are protected from such an inflammatory response even with increased adiposity. The inflammatory tone in males is linked to insulin resistance and might be the underlying cause for sex differences in metabolic disease. Factors regulating the meta-inflammatory response remain unclear but enhanced lipid storage in females may explain the reduced inflammatory response to high-fat diets. In this study, we evaluated lean and obese females with stimulated lipolysis to understand whether a stress release of free fatty acids (FFAs) could induce female ATMs. We demonstrate that in both lean and obese females, GWAT CD11c(−) resident ATMs accumulate with β-3 adrenergic receptor–stimulated lipolysis. Lipolysis elevated serum FFA, triglyceride, and IL-6 levels in females that corresponded to significant phosphorylated hormone-sensitive lipase and adipose triglyceride lipase protein expression in obese female GWAT compared with males. Increased lipolytic response in obese females was associated with crown-like structures and induced Il6, Mcp1, Arg1, and Mgl1 expression in obese female GWAT, suggesting an environment of lipid clearance and adipose remodeling. With this finding we next investigated whether lipid storage and lipolytic mediators differed by sex. Diacylglycerol, ceramides, phospholipids, and certain fatty acid species associated with inflammation were elevated in male GWAT compared with obese female GWAT. Overall, our data demonstrate a role for GWAT lipid storage and lipolytic metabolites to induce inflammation in males and induce remodeling in females that might explain sex differences in overall metabolic health.

PURPOSE OF REVIEW: As the ongoing epidemic of adult and childhood obesity grows, it puts a greater burden on individuals and the healthcare system due to increased prevalence of obesity-associated diseases. An important area that has gained much attention recently is the sex and gender difference related to obesity and associated complications. Basic science and clinical studies have now improved our understanding of obesity and have discovered adipose tissue biology to be key in metabolism. RECENT FINDINGS: There is evidence related to the sex dichotomy in obesity in a variety of areas including adipocyte function, sex hormone effects, genetics, and metabolic inflammation leading to critical differences in adipose tissue biology. SUMMARY: The sex and gender difference in adipose tissue is a factor that should be considered when studying an individuals’ risk for obesity and metabolic dysfunction. This understanding is important for strategizing treatment and prevention measures.

Men have a higher risk of metabolic and cardiovascular disease than pre-menopausal women, but the mechanisms of these differences are elusive. Chronic myeloid inflammation during obesity contributes to metabolic disease risk and is significantly more robust in males. Given the paucity of data on male sex hormones contributing to macrophage responses in obesity, our objective was to understand the role of androgens in promoting obesity-induced myeloid inflammation. Male and female C57Bl/6J mice were fed a 60% high fat diet for 24 weeks. Glucose tolerance and insulin sensitivity were measured. Monocyte transfer experiments assessed sex differences in bone marrow myeloid responses to obesity independent of host sex. Gonadectomy, mice deficient of androgen receptor signaling (ARtfm) and monocyte specific androgen receptor (AR) knockout mice (LysMAR-/y) were used to model androgen deficiency. Compared to males, females had dampened inflammatory responses with reduced CD11c+ ATMs and cytokines, even with increased adiposity. RNASeq demonstrated sex differences in gene pathways of both metabolic and inflammatory activation in ATMs. Male monocytes transferred into females remained primed for pro-inflammatory response and induced an increase in adiposity. Castrated males exposed to high fat diet had impaired glucose tolerance and increased insulin sensitivity with increased adiposity and lower numbers of CD11c+ ATMs. These same findings were seen in ARtfm mice. Testosterone enhanced palmitate-stimulated myeloid colony production, and this response was dampened in castrated, ARtfm, and LysMAR-/y mice. These studies demonstrate that androgens play a critical role in enhanced metabolic dysfunction and enhanced myeloid inflammation in response to obesogenic cues. Androgen driven myeloid inflammation leads to metabolic dysfunction in a cell-autonomous manner driving sex-differences in obesity induced meta-inflammation. Disclosure C.A. Griffin: None. S. Abrishami: None. M. Varghese: None. K. Singer: None.

Men and post-menopausal women are at greater risk for cardiovascular diseases and diabetes than younger women. In obese rodent models, males exhibit profound adipose tissue macrophage (ATM) accumulation in gonadal white adipose tissue (GWAT) linked to insulin resistance, while females are protected even with enhanced adiposity. We hypothesize that these inflammatory differences may be a result of altered lipolysis responses and that females would have enhanced ATM accumulation when lipolysis is induced. Lipolysis was stimulated with a beta3 adrenergic receptor (ADRB3) agonist CL-316, 243 in C57Bl6/j male and female mice fed 16 weeks of 60% high fat diet (HFD). GWAT leukocytes were isolated after 18 h and evaluated by flow cytometry. Lipogenic, lipolytic, oxidative and inflammatory gene expression along with immunofluorescence were performed. ADRB3 activation did not alter adipose tissue weights, but significantly reduced liver weights in obese females. Obese CL treated female mice showed elevated serum free fatty acid (FFA) and triglyceride (TG) levels compared to levels induced in males. Lipid overload impaired TG storage and utilization genes- Lpl, Fasn, Acsl1, Hsl, and Glut4 expression in obese females. Lipolysis promoted appearance of crown like structures (CLS) in males and females but only induced Il6 proinflammatory cytokine and Mcp1 chemokine expression in obese female GWAT. Activated lipolysis triggered CD11c- ATM accumulation in lean females but in both obese male and female GWAT. Obese males showed a marked reduction in GWAT dendritic cells (DC) but a significant reduction in both GWAT and inguinal WAT DCs of obese females. While obese females are resistant to inflammation, this study shows that induced lipolysis elevates FFA levels, alters lipid metabolism and increased CD11c- ATMs and CLSs in obese females. Elucidating the link between lipolysis and inflammation can better explain sex differences in overall metabolic health leading to targeted treatment strategies. Disclosure M. Varghese: None. S. Abrishami: None. K. Singer: None.