Sepsis remains one of the leading causes of death in burn patients who survive the initial insult of injury. Disruption of the intestinal epithelial barrier has been shown after burn injury; this can lead to the translocation of bacteria or their products (e.g., endotoxin) from the intestinal lumen to the circulation, thereby increasing the risk for sepsis in immunocompromised individuals. Since the maintenance of the epithelial barrier is largely dependent on the intestinal microbiota, we examined the diversity of the intestinal microbiome of severely burned patients and a controlled mouse model of burn injury. We show that burn injury induces a dramatic dysbiosis of the intestinal microbiome of both humans and mice and allows for similar overgrowths of Gram-negative aerobic bacteria. Furthermore, we show that the bacteria increasing in abundance have the potential to translocate to extra-intestinal sites. This study provides an insight into how the diversity of the intestinal microbiome changes after burn injury and some of the consequences these gut bacteria can have in the host.

Interleukin (IL)-6 decreases cardiac contractility via a nitric oxide (NO)-dependent pathway. However, mechanisms underlying IL-6-induced NO production remain unclear. JAK2/STAT3 and ERK1/2 are two well known signaling pathways activated by IL-6 in non-cardiac cells. However, these IL-6-activated pathways have not been identified in adult cardiac myocytes. In this study, we identified activation of these two pathways during IL-6 stimulation and examined their roles in IL-6-induced NO production and decrease in contractility of adult ventricular myocytes. IL-6 increased phosphorylation of STAT3 (at Tyr 705 ) and ERK1/2 (at Tyr 204 ) within 5 min that peaked at 15-30 min and returned to basal levels at 2 h. Phosphorylation of STAT3 was blocked by genistein, a protein tyrosine kinase inhibitor, and AG490, a JAK2 inhibitor, but not PD98059, an ERK1/2 kinase inhibitor. The phosphorylation of ERK1/2 was blocked by PD98059 and genistein but not AG490. Furthermore, IL-6 enhanced de novo synthesis of iNOS protein, increased NO production, and decreased cardiac contractility after 2 h of incubation. These effects were blocked by genistein and AG490 but not PD98059. We conclude that IL-6 activated independently the JAK2/STAT3 and ERK1/2 pathways, but only JAK2/ STAT3 signaling mediated the NO-associated decrease in contractility.

A recent report indicated that hyperhomocysteinemia (Hhe), in addition to its atherothrombotic effects, exacerbates the adverse cardiac remodeling seen in response to hypertension, a powerful stimulus for pathological ventricular hypertrophy. The present study was undertaken to determine whether Hhe has a direct effect on ventricular remodeling and function in the absence of other hypertrophic stimuli. Male Wistar-Kyoto rats were fed either an amino acid-defined control diet or an intermediate Hhe-inducing diet. After 10 wk of dietary treatment, rats were subjected to echocardiographic assessment of left ventricular (LV) dimensions and systolic function. Subsequently, blood was collected for plasma homocysteine measurements, and the rats were killed for histomorphometric and biochemical assessment of cardiac remodeling and for in vitro cardiac function studies. Significant LV hypertrophy was detected by echocardiographic measurements, and in vitro results showed hypertrophy with significantly increased myocyte size in the LV and right ventricle (RV). LV and RV remodeling was characterized by a disproportionate increase in perivascular and interstitial collagen, coronary arteriolar wall thickening, and myocardial mast cell infiltration. In vitro study of LV function demonstrated abnormal diastolic function secondary to decreased compliance because the rate of relaxation did not differ between groups. LV systolic function did not vary between groups in vitro. In summary, in the absence of other hypertrophic stimuli short-term intermediate Hhe caused pathological hypertrophy and remodeling of both ventricles with diastolic dysfunction of the LV. These results demonstrate that Hhe has direct adverse effects on cardiac structure and function, which may represent a novel direct link between Hhe and cardiovascular morbidity and mortality, independent of other risk factors.

No abstract

Hyperhomocysteinemia (Hhe), linked to cardiovascular disease by epidemiological studies, may be an important factor in adverse cardiac remodeling in hypertension. Specifically, convergence of myocardial and vascular alterations promoted by Hhe and hypertension may exacerbate cardiac remodeling and myocardial dysfunction. We studied male spontaneously hypertensive rats fed one of three diets: control, intermediate Hhe inducing, or severe Hhe inducing. After 10 wk of dietary intervention, cardiac function was assessed in vitro, and cardiac and coronary arteriolar remodeling were monitored by histomorphometric, immunohistochemical, and biochemical techniques. Results showed that Hhe induced diastolic dysfunction, as characterized by the diastolic pressure-volume curve, without significant changes in baseline systolic function. Perivascular collagen levels were increased by Hhe, and there was an increase in left ventricular hydroxyproline levels. Myocyte size was not affected. Coronary arteriolar wall thickness increased with Hhe due to smooth muscle hyperplasia. Mast cells increased in parallel with Hhe and collagen accumulation. In summary, 10 wk of Hhe caused coronary arteriolar remodeling, myocardial collagen deposition, and diastolic dysfunction in hypertensive rats.

Context: Polycystic ovary syndrome (PCOS) is associated with insulin resistance and obesity. Recent studies have shown that serum retinol-binding protein 4 (RBP4) levels increase with obesity. Currently, no data exist on the relative expression of RBP4 in either serum or adipose tissue of PCOS women.Objectives: mRNA expression of RBP4 from sc and omental (om) adipose tissue and sc adipocytes in overweight PCOS women were compared with matched controls; RBP4 protein in adipose tissue and serum RBP4 levels were also assessed. Additionally, we studied the effects of testosterone, 17␤-estradiol, androstenedione, and dehydroepiandrosterone sulfate on RBP4 expression in adipose tissue explants.Design: Real-time RT-PCR and Western blotting were used to assess the relative mRNA and protein expression of RBP4. Biochemical measurements were also performed.Results: Compared with controls, there was significant up-regulation of RBP4 mRNA in sc (P Ͻ 0.05) and om (P Ͻ 0.01) adipose tissue as well as isolated sc adipocytes (P Ͻ 0.01) of PCOS women. In addition to elevated serum RBP4 levels in PCOS women (P Ͻ 0.05), RBP4 protein levels were significantly greater in sc and om adipose tissue of PCOS women (P Ͻ 0.05 and P Ͻ 0.05, respectively). Furthermore, in human sc and om adipose tissue explants, 17␤-estradiol significantly increased RBP4 mRNA expression, protein levels, and secretion into the culture media (P Ͻ 0.05). Conclusions:The precise reason for elevated levels of RBP4 in overweight PCOS women is unknown, but it appears that 17␤-estradiol may play a role in their regulation in adipose tissue. (J Clin Endocrinol Metab 92: 2764 -2772, 2007) P OLYCYSTIC OVARY SYNDROME (PCOS) is characterized by menstrual dysfunction and hyperandrogenism and is associated with insulin resistance (IR), impaired glucose tolerance, type 2 diabetes mellitus (T2DM), dyslipidemia, and visceral obesity (1, 2). The consequent hyperinsulinemia is more prevalent in lean and obese women with PCOS when compared with age-and weight-matched normal women (3).The metabolic syndrome is associated with excessive accumulation of central body fat. Besides its role in energy storage, adipose tissue produces several hormones and cytokines that have wide-ranging effects on carbohydrate and lipid metabolism. They appear to play an important role in the pathogenesis of IR, diabetes, and atherosclerosis (4). Studies of adipocyte-specific glucose transporter 4 (GLUT4) knockout mice recognized retinol-binding protein 4 (RBP4) as an adipokine that contributes to IR in obesity and T2DM by inducing the expression of hepatic gluconeogenic enzymes and impairing insulin signaling in muscle (5). Additional studies revealed elevated serum/plasma RBP4 levels in humans with obesity, impaired glucose tolerance, and T2DM (5, 6). More recently, studies on isolated human sc primary adipocytes have confirmed RBP4 as a human adipokine (7).Because PCOS is a prodiabetic state with a higher prevalence of obesity (1, 2), we measured serum RBP4 levels and studied the mRNA expression and ...

High exposures of Vietnam veterans to 2,3,7, 8-Tetrachlorodibenzo-p-dioxin, a dioxin contained in the herbicide mixture Agent Orange, have previously been demonstrated to be associated with an increased prevalence of diabetes and hyperinsulinemia in non-diabetic subjects. Sixty-nine persons were identified who were in good health and had normal glucose levels during glucose tolerance testing. These subjects lived within 25 miles of the Vertac/Hercules Superfund site located in Jacksonville, Arkansas. The blood sera lipid concentrations of TCDD for the 69 subjects ranged between 2 and 94 ppt. When subjects with blood sera lipid TCDD levels in the top 10% (TCDD > 15 ppt, n = 7) were compared to subjects with lower levels (2-15 ppt, n = 62), there were no group differences in age, obesity, gender distribution, total lipids, or glucose levels. However, plasma insulin concentrations, at fasting and 30, 60, and 120 min following a 75 g glucose load, were significantly higher in the group with high blood TCDD levels. These finding could not be explained by other known risk factors for hyperinsulinemia. The finding of the TCDD-hyperinsulinemia relationship is consistent with studies of Vietnam veterans and suggests that high blood TCDD levels may cause insulin resistance.

Background Although the risk of exposure to SARS-CoV-2 is higher for frontline healthcare workers, not all personnel have similar risks. Determining infection rate is difficult due to the limits on testing and the high rate of asymptomatic individuals. Detection of antibodies against SARS-CoV-2 may be useful for determining prior exposure to the virus and assessing mitigation strategies, such as isolation, masks, and other protective equipment. Methods An online assessment that included demographic, clinical, and exposure information and a blood sample was collected from 20,614 participants out of ~43,000 total employees at Beaumont Health, which includes eight hospitals distributed across the Detroit metropolitan area in southeast Michigan. The presence of anti-SARS-CoV-2 IgG was determined using the EUROIMMUN assay. Results A total of 1,818 (8.8%) participants were seropositive between April 13 and May 28, 2020. Among the seropositive individuals, 44% reported that they were asymptomatic during the month prior to blood collection. Healthcare roles such as phlebotomy, respiratory therapy, and nursing/nursing support exhibited significantly higher seropositivity. Among participants reporting direct exposure to a COVID-19 positive individual, those wearing an N95/PAPR mask had a significantly lower seropositivity rate (10.2%) compared to surgical/other masks (13.1%) or no mask (17.5%). Conclusions Direct contact with COVID-19 patients increased the likelihood of seropositivity among employees but study participants who wore a mask during COVID-19 exposures were less likely to be seropositive. Additionally, a large proportion of seropositive employees self-reported as asymptomatic. (Funded by Beaumont Health and by major donors through the Beaumont Health Foundation) ClinicalTrials.gov number NCT04349202