Involvement of the gut microbiota in cancer cachexia.

Cancer cachexia, or the unintentional loss of body weight in patients with cancer, is a multiorgan and multifactorial syndrome with a complex and largely unknown etiology; however, metabolic dysfunction and inflammation remain hallmarks of cancer-associated wasting. Although cachexia manifests with muscle and adipose tissue loss, perturbations to the gastrointestinal tract may serve as the frontline for both impaired nutrient absorption and immune-activating gut dysbiosis. Investigations into the gut microbiota have exploded within the past two decades, demonstrating multiple gut-tissue axes; however, the link between adipose and skeletal muscle wasting and the gut microbiota with cancer is only beginning to be understood. Furthermore, the most used anticancer drugs (e.g. chemotherapy and immune checkpoint inhibitors) negatively impact gut homeostasis, potentially exacerbating wasting and contributing to poor patient outcomes and survival. In this review, we 1) highlight our current understanding of the microbial changes that occur with cachexia, 2) discuss how microbial changes may contribute to adipose and skeletal muscle wasting, and 3) outline study design considerations needed when examining the role of the microbiota in cancer-induced cachexia.

Analysis of the Impact of a Multi-Strain Probiotic on Body Composition and Cardiorespiratory Fitness in Long-Distance Runners.

Use of probiotic supplements, the benefits of which have not been proven in sportspeople, is becoming more widespread among runners. The aim of this study was to evaluate the effect of a multi-strain probiotic on body composition, cardiorespiratory fitness and inflammation in the body. The randomised, double-blind study included 66 long-distance runners. The intervention factor was a multi-strain probiotic or placebo. At the initial and final stages of the study, evaluation of body composition and cardiorespiratory fitness was performed and the presence of inflammation determined. In the group of men using the probiotic, an increase in lean body mass (p = 0.019) and skeletal muscle mass (p = 0.022) was demonstrated, while in the group of women taking the probiotic, a decrease in the content of total body fat (p = 0.600) and visceral fat (p = 0.247) was observed. Maximum oxygen consumption (VO2max) increased in women (p = 0.140) and men (p = 0.017) using the probiotic. Concentration of tumour necrosis factor-alpha decreased in women (p = 0.003) and men (p = 0.001) using the probiotic and in women (p = 0.074) and men (p = 0.016) using the placebo. Probiotic therapy had a positive effect on selected parameters of body composition and cardiorespiratory fitness of study participants and showed a tendency to reduce inflammation.

Translocation of Viable Gut Microbiota to Mesenteric Adipose Drives Formation of Creeping Fat in Humans.

A mysterious feature of Crohn's disease (CD) is the extra-intestinal manifestation of "creeping fat" (CrF), defined as expansion of mesenteric adipose tissue around the inflamed and fibrotic intestine. In the current study, we explore whether microbial translocation in CD serves as a central cue for CrF development. We discovered a subset of mucosal-associated gut bacteria that consistently translocated and remained viable in CrF in CD ileal surgical resections, and identified Clostridium innocuum as a signature of this consortium with strain variation between mucosal and adipose isolates, suggesting preference for lipid-rich environments. Single-cell RNA sequencing characterized CrF as both pro-fibrotic and pro-adipogenic with a rich milieu of activated immune cells responding to microbial stimuli, which we confirm in gnotobiotic mice colonized with C. innocuum. Ex vivo validation of expression patterns suggests C. innocuum stimulates tissue remodeling via M2 macrophages, leading to an adipose tissue barrier that serves to prevent systemic dissemination of bacteria.

Adipose tissue derived bacteria are associated with inflammation in obesity and type 2 diabetes.

OBJECTIVE: Bacterial translocation to various organs including human adipose tissue (AT) due to increased intestinal permeability remains poorly understood. We hypothesised that: (1) bacterial presence is highly tissue specific and (2) related in composition and quantity to immune inflammatory and metabolic burden. DESIGN: We quantified and sequenced the bacterial 16S rRNA gene in blood and AT samples (omental, mesenteric and subcutaneous) of 75 subjects with obesity with or without type 2 diabetes (T2D) and used catalysed reporter deposition (CARD) - fluorescence in situ hybridisation (FISH) to detect bacteria in AT. RESULTS: Under stringent experimental and bioinformatic control for contaminants, bacterial DNA was detected in blood and omental, subcutaneous and mesenteric AT samples in the range of 0.1 to 5 pg/µg DNA isolate. Moreover, CARD-FISH allowed the detection of living, AT-borne bacteria. Proteobacteria and Firmicutes were the predominant phyla, and bacterial quantity was associated with immune cell infiltration, inflammatory and metabolic parameters in a tissue-specific manner. Bacterial composition differed between subjects with and without T2D and was associated with related clinical measures, including systemic and tissues-specific inflammatory markers. Finally, treatment of adipocytes with bacterial DNA in vitro stimulated the expression of TNFA and IL6. CONCLUSIONS: Our study provides contaminant aware evidence for the presence of bacteria and bacterial DNA in several ATs in obesity and T2D and suggests an important role of bacteria in initiating and sustaining local AT subclinical inflammation and therefore impacting metabolic sequelae of obesity.

Impact of bariatric surgery on type 2 diabetes: contribution of inflammation and gut microbiome?

Obesity is a chronic low-grade inflammatory disease (both at the systemic and adipose tissue level) that continues to rise worldwide. It is associated with an abundance of comorbidities, including type 2 diabetes (T2D). Bariatric surgery, which induces modifications of the intestinal tract, is to date the most successful treatment for obesity. Its use has dramatically increased in number as it enables both weight reduction and metabolic improvements, with 60% of patients even achieving diabetes remission. Several mechanisms are actually demonstrated to be involved in those clinical improvements. Importantly, both obesity and T2D share many phenotypic characteristics, including increased systemic and adipose tissue inflammation, as well as gut microbiota dysbiosis. These characteristics are deeply modulated after bariatric surgery. This review will address the host metabolic changes observed after bariatric surgery, focusing on the induced gut architectural changes, as well as on the modifications of the inflammatory tone and the gut microbiota.

Comparison of Antibacterial and Immunological Properties of Mesenchymal Stem/Stromal Cells from Equine Bone Marrow, Endometrium, and Adipose Tissue.

Equine mesenchymal stem/stromal cells (MSCs) are multipotent cells that are widely used for treatment of musculoskeletal injuries, and there is significant interest in expanding their application to nonorthopedic conditions. MSCs possess antibacterial and immunomodulatory properties that may be relevant for combating infection; however, comparative studies using MSCs from different origins have not been carried out in the horse, and this was the focus of this study. Our results showed that MSC-conditioned media attenuated the growth of Escherichia coli, and that this effect was, on average, more pronounced for endometrium (EM)-derived and adipose tissue (AT)-derived MSCs than for bone marrow (BM)-derived MSCs. In addition, the antimicrobial lipocalin-2 was expressed at mean higher levels in EM-MSCs than in AT-MSCs and BM-MSCs, and the bacterial component lipopolysaccharide (LPS) stimulated its production by all three MSC types. We also showed that MSCs express interleukin-6 (IL-6), IL-8, monocyte chemoattractant protein-1, chemokine ligand-5, and Toll-like receptor 4, and that, in general, these cytokines were induced in all cell types by LPS. Low expression levels of the macrophage marker colony-stimulating factor 1 receptor were detected in BM-MSCs and EM-MSCs but not in AT-MSCs. Altogether, these findings suggest that equine MSCs from EM, AT, and BM have both direct and indirect antimicrobial properties that may vary between MSCs from different origins and could be exploited toward improvement of regenerative therapies for horses.

Anti-inflammatory effects of heat-killed Lactobacillus plantarum L-137 on cardiac and adipose tissue in rats with metabolic syndrome.

The effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) on chronic inflammation associated with metabolic disorders have remained unknown. We examined the effects of HK L-137 on cardiac and adipose tissue pathophysiology in DahlS.Z-Lepr fa /Lepr fa (DS/obese) rats as a model of metabolic syndrome. DS/obese rats were treated orally with HK L-137 (2 or 75 mg kg-1 day-1) from 9 to 13 weeks of age. HK L-137 attenuated left ventricular (LV) inflammation and fibrosis as well as adipocyte hypertrophy, inflammation, and up-regulation of sterol regulatory element-binding protein-1c (SREBP-1c) gene expression in visceral and subcutaneous adipose tissue, without affecting body weight gain or hypertension. The low dose of HK L-137 also ameliorated LV diastolic dysfunction, the increase in subcutaneous fat mass, and insulin resistance as well as attenuated the down-regulation of Akt phosphorylation in visceral and subcutaneous adipose tissue, and the elevation of the circulating interleukin-6 concentration. Furthermore, the proportion of regulatory T (Treg) cells among CD4+ T cells in the spleen was increased by HK L-137. These results suggest that the anti-inflammatory effects of HK L-137 on the heart and adipose tissue are related, at least partly, to suppression of systemic inflammation associated with an increase in splenic Treg cell.

Epicardial adipose tissue microbial colonization and inflammasome activation in acute coronary syndrome.

BACKGROUND: Epicardial adipose tissue (EAT) has a close functional and anatomic relationship with epicardial coronary arteries. Accumulating evidence suggests that host microbiome alterations may play a role in several inflammatory/immune disorders, triggering a robust proinflammatory response also involving interleukin-1ß (IL-1ß) and the NALP3 inflammasome. In the current study, we explore the hypothesis that in patients with non-ST elevation acute coronary syndrome (ACS), EAT contains potentially pro-atherosclerotic bacteria that might elicit inflammasome activation. METHODS: EAT samples were obtained during coronary artery bypass grafting from ACS (n=18) and effort stable angina (SA; n=16) patients, and as controls, from patients with angiographically normal coronary arteries undergoing surgery for mitral insufficiency (MVD; n=13). In all patients, NALP3 and proIL-1ß mRNA expressions were evaluated with qRT-PCR. In 3 patients from each group, EAT microbiota composition was determined using next-generation sequencing technologies. RESULTS: In EAT, mRNA expression of both NALP3 and pro-IL1ß was significantly higher in ACS than in SA and MVD (P=0.028 and P=0.005, respectively). A broad range of bacterial species (n=76) was identified in both ACS and SA, with different predominant species. In contrast, microbial DNA was barely observed in MVD. CONCLUSIONS: Our study demonstrated the presence of bacterial DNA directly into EAT, surrounding diseased coronary arteries, of patients with ACS. Furthermore, ACS is associated with NALP3/inflammasome pathway activation in EAT. Our data suggest that the EAT environment is susceptible to microbial colonization that might stimulate a proinflammatory response. These findings add new elements to the pathogenesis of ACS and suggest novel therapeutic targets.

Gut commensal Bacteroides acidifaciens prevents obesity and improves insulin sensitivity in mice.

In humans, the composition of gut commensal bacteria is closely correlated with obesity. The bacteria modulate metabolites and influence host immunity. In this study, we attempted to determine whether there is a direct correlation between specific commensal bacteria and host metabolism. As mice aged, we found significantly reduced body weight and fat mass in Atg7ΔCD11c mice when compared with Atg7f/f mice. When mice shared commensal bacteria by co-housing or feces transfer experiments, body weight and fat mass were similar in both mouse groups. By pyrosequencing analysis, Bacteroides acidifaciens (BA) was significantly increased in feces of Atg7ΔCD11c mice compared with those of control Atg7f/f mice. Wild-type C57BL/6 (B6) mice fed with BA were significantly more likely to gain less weight and fat mass than mice fed with PBS. Of note, the expression level of peroxisome proliferator-activated receptor alpha (PPARα) was consistently increased in the adipose tissues of Atg7ΔCD11c mice, B6 mice transferred with fecal microbiota of Atg7ΔCD11c mice, and BA-fed B6 mice. Furthermore, B6 mice fed with BA showed elevated insulin levels in serum, accompanied by increased serum glucagon-like peptide-1 and decreased intestinal dipeptidyl peptidase-4. These finding suggest that BA may have potential for treatment of metabolic diseases such as diabetes and obesity.

The effects of silver, silicon-containing apatite towards bacteria and cell responses.

An integrated approach is proposed to incorporate silicon and silver into hydroxyapatite (HA) to enhance the biological response and reduce implant-related infection in bone substitutes. This study examined the responses of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria to silver, silicon-containing apatite (Ag,Si-HA). Scanning electron microscopy images revealed significant reduction in adherence of S. aureus and E. coli bacteria on Ag,Si-HA as compared to HA. The antibacterial property of Ag,Si-HA was shown from a 7-log reduction of S. aureus population in the test solution and on the sample's surface as compared to HA at day 7. Rapid inhibition of the adherent bacteria suggested that the antibacterial action of Ag incorporated in Ag,Si-HA could be attributed to the Ag(+) ions on the crystal surface rather than the released Ag(+) ions. Presence of Ag may influence the biological response of HA and as such, the long-term interaction between human adipose-derived mesenchymal stem cells and Ag,Si-HA was evaluated in-vitro. An alamarBlue™ assay showed higher cell proliferation for Ag,Si-HA as compared to HA from day 3 onwards. Immunofluorescence staining revealed well-spread actin cytoskeletons on Ag,Si-HA. In addition, signs of extracellular matrix secretion and biomineralization were observed on Ag,Si-HA at day 14 onwards. Results demonstrated enhanced bone differentiation on Ag,Si-HA, as indicated by a higher level of protein expressions (type 1 collagen and osteocalcin) from day 14 to 21. Therefore, the incorporation of Ag and Si complement each other by endowing HA with antibacterial property, and concurrently promoting biological performance of the cells.

Gut microbiota controls adipose tissue expansion, gut barrier and glucose metabolism: novel insights into molecular targets and interventions using prebiotics.

Crosstalk between organs is crucial for controlling numerous homeostatic systems (e.g. energy balance, glucose metabolism and immunity). Several pathological conditions, such as obesity and type 2 diabetes, are characterised by a loss of or excessive inter-organ communication that contributes to the development of disease. Recently, we and others have identified several mechanisms linking the gut microbiota with the development of obesity and associated disorders (e.g. insulin resistance, type 2 diabetes, hepatic steatosis). Among these, we described the concept of metabolic endotoxaemia (increase in plasma lipopolysaccharide levels) as one of the triggering factors leading to the development of metabolic inflammation and insulin resistance. Growing evidence suggests that gut microbes contribute to the onset of low-grade inflammation characterising these metabolic disorders via mechanisms associated with gut barrier dysfunctions. We have demonstrated that enteroendocrine cells (producing glucagon-like peptide-1, peptide YY and glucagon-like peptide-2) and the endocannabinoid system control gut permeability and metabolic endotoxaemia. Recently, we hypothesised that specific metabolic dysregulations occurring at the level of numerous organs (e.g. gut, adipose tissue, muscles, liver and brain) rely from gut microbiota modifications. In this review, we discuss the mechanisms linking gut permeability, adipose tissue metabolism, and glucose homeostasis, and recent findings that show interactions between the gut microbiota, the endocannabinoid system and the apelinergic system. These specific systems are discussed in the context of the gut-to-peripheral organ axis (intestine, adipose tissue and brain) and impacts on metabolic regulation. In the present review, we also briefly describe the impact of a variety of non-digestible nutrients (i.e. inulin-type fructans, arabinoxylans, chitin glucans and polyphenols). Their effects on the composition of the gut microbiota and activity are discussed in the context of obesity and type 2 diabetes.

Differences in visceral fat and fat bacterial colonization between ulcerative colitis and Crohn's disease. An in vivo and in vitro study.

Crohn's disease (CD) is notably characterized by the expansion of visceral fat with small adipocytes expressing a high proportion of anti-inflammatory genes. Conversely, visceral fat depots in ulcerative colitis (UC) patients have never been characterized. Our study aims were a) to compare adipocyte morphology and gene expression profile and bacterial translocation in omental (OM) and mesenteric (MES) adipose tissue of patients with UC and CD, and b) to investigate the effect of bacterial infection on adipocyte proliferation in vitro. Specimens of OM and MES were collected from 11 UC and 11 CD patients, processed and examined by light microscopy. Gene expression profiles were evaluated in adipocytes isolated from visceral adipose tissue using microarray and RTqPCR validations. Bacteria within adipose tissue were immuno-detected by confocal scanning laser microscopy. Adipocytes were incubated with Enterococcus faecalis and cells counted after 24 h. Morphology and molecular profile of OM and MES revealed that UC adipose tissue is less inflamed than CD adipose tissue. Genes linked to inflammation, bacterial response, chemotaxis and angiogenesis were down-regulated in adipocytes from UC compared to CD, whereas genes related to metallothioneins, apoptosis pathways and growth factor binding were up-regulated. A dense perinuclear positivity for Enterococcus faecalis was detected in visceral adipocytes from CD, whereas positivity was weak in UC. In vitro bacterial infection was associated with a five-fold increase in the proliferation rate of OM preadipocytes. Compared to UC, visceral adipose tissue from CD is more inflamed and more colonized by intestinal bacteria, which increase adipocyte proliferation. The influence of bacteria stored within adipocytes on the clinical course of IBD warrants further investigations.

Harnessing the beneficial properties of adipogenic microbes for improving human health.

Obesity is associated with numerous metabolic comorbidities. Weight loss is an effective measure for alleviating many of these metabolic abnormalities. However, considering the limited success of most medical weight-management approaches in producing a sustained weight loss, approaches that improve obesity-related metabolic abnormalities independent of weight loss would be extremely attractive and of practical benefit. Metabolically healthy obesity supports the notion that a better metabolic profile is possible despite obesity. Moreover, adequate expansion of adipose tissue appears to confer protection from obesity-induced metabolic comorbidities. To this end, the 10th Stock conference examined new approaches to improve metabolic comorbidities independent of weight loss. In particular, human adenovirus 36 (Ad36) and specific gut microbes were examined for their potential to influence lipid and glucose homeostasis in animals and humans. While these microbes possess some undesirable properties, research has identified attributes of adenovirus Ad36 and gut microbes that may be selectively harnessed to improve metabolic profile without the obligatory weight loss. Furthermore, identifying the host signalling pathways that these microbes recruit to improve the metabolic profile may offer new templates and targets, which may facilitate the development of novel treatment strategies for obesity-related metabolic conditions.

Factors influencing mortality in patients undergoing surgery for acute pancreatitis: importance of peripancreatic tissue and fluid infection.

OBJECTIVES: The aims of present study were to analyze the mortality risk factors in patients who had surgery for acute pancreatitis and to assess the importance of culturing peripancreatic tissue or fluid infection to ascertain the infection status. METHODS: Surgery was indicated both in patients with infected severe acute pancreatitis and in those with sterile pancreatitis with an unfavorable course. During surgery, cultures were taken of tissues (pancreatic necrosis and peripancreatic fat), intra-abdominal fluid, and bile. RESULTS: Of 107 patients operated on, fluid culture was analyzed in 94 patients, pancreatic necrosis in 61 patients, peripancreatic fat in 39 patients, and bile in 38 patients. Sterile pancreatitis with sterile ascites was found in 17 patients, sterile pancreatitis with infected ascites in 22, and pancreatic tissue infection in 60. Multivariate analysis demonstrated that sterile tissue cultures, age over 65 years, and fewer than 12 days between the beginning of pain and surgery were risk factors for mortality. Sterile pancreatitis with sterile ascites and sterile pancreatitis with infected ascites had similar postoperative mortality (41% and 50%, respectively); the group with pancreatic tissue infection had a lower mortality (20%). CONCLUSIONS: Early surgery, advanced age, and sterility of tissue cultures have been demonstrated as mortality factors for acute pancreatitis. Intra-abdominal fluid may be infected in the presence of sterile necrosis.

Distribution of resveratrol metabolites in liver, adipose tissue, and skeletal muscle in rats fed different doses of this polyphenol.

This study aimed to characterize resveratrol metabolite profiles in liver, skeletal muscle, and adipose tissue in rats treated for 6 weeks with 6, 30, or 60 mg of trans-resveratrol/kg body weight/d. Resveratrol metabolites were quantified by liquid chromatography-tandem mass spectrometry. The greatest number of metabolites was found in liver followed by adipose tissue. A great number of metabolites in muscle was below the limit of detection. The amounts of sulfate conjugates tended to increase when resveratrol dosage was enhanced, while the glucuronide ones increased only between 6 and 30 mg/kg/d. Microbiota metabolites were detected in higher amounts than resveratrol conjugates in liver, while the opposite occurred in adipose tissue and muscle. So, the largest amounts of resveratrol metabolites were found in liver, intermediate amounts in adipose tissue, and the lowest amounts in muscle. Sulfate conjugates, but not glucuronides, showed a dose-response pattern. Microbiota metabolites were predominant in liver.

The intestinal microbiota and obesity.

Obesity has been and continues to be an epidemic in the United States. Obesity has been addressed in multiple health initiatives, including Healthy People 2010, with no state meeting the proposed goal of a prevalence of obesity < 15% of the adult population. In contrast, obesity rates have continued to increase, with the self-reported prevalence of obesity among adults increasing by 1.1% from 2007 to the present. Indeed, since 2009, 33 states reported obesity prevalences of 25% or more with only 1 state reporting prevalence < 20%. There have been multiple approaches for the treatment of obesity, including fad diets, incentive-based exercise programs, and gastric bypass surgery; none of which have been optimal. In a murine model, it was shown that the majority of the intestinal microbiome consists of two bacterial phyla, the Bacteroidetes and the Firmicutes, and that the relative abundance of these two phyla differs among lean and obese mice; the obese mouse had a higher proportion of Firmicutes to Bacteroidetes (50% greater) than the lean mouse. The same results were appreciated in obese humans compared to lean subjects. The postulated explanation for this finding is that Firmicutes produce more complete metabolism of a given energy source than do Bacteroidetes, thus promoting more efficient absorption of calories and subsequent weight gain. Researchers were able to demonstrate that colonizing germ-free mice with the intestinal microbiome from obese mice led to an increased total body fat in the recipient mice despite a lack of change in diet. The converse, that, colonizing germ-free obese mice with the intestinal microbiome of thin mice causing a decreased total body fat in the recipient mice, has not yet been done. Other possible mechanisms by which the intestinal microbiome affects host obesity include induction of low-grade inflammation with lipopolysaccharide, regulation of host genes responsible for energy expenditure and storage, and hormonal communication between the intestinal microbiome and the host. The following review discusses the microbiome-obesity relationship and proposed mechanisms by which the intestinal microbiota is hypothesized to influence weight gain.

Bariatric surgery, adipose tissue and gut microbiota.

Human obesity can be viewed as a set of phenotypes that evolve over time in a sequence of stages that need to be precisely measured. Environmental, behavioral, genetic and biological factors interact to cause obesity. This presentation provides a clinical viewpoint on some biological processes that may explain some of the stages in the development of human obesity, its chronic maintenance and occurrence of complications, with a focus on brain structures, genetics, the profound alterations in adipose tissue biology and gut microbiota components. Roux-en-Y gastric bypass surgery is an increasingly effective model to study in this context because it leads to major improvements in glucose and lipid homeostasis and to the amelioration of some systemic inflammatory markers.

Adiponectin is required for enhancement of CCL2 expression in adipose tissue during Listeria monocytogenes infection.

Obesity is an important background of metabolic syndrome progression. Our previous study demonstrated that chemokine CCL2 expression was suppressed in liver of obese mice that were highly susceptible to Listeria monocytogenes infection. We investigated the role of adiponectin in CCL2 expression in obese mice after L. monocytogenes infection. When leptin-deficient obese ob/ob mice were infected intraperitoneally with L. monocytogenes, the elimination of bacteria from spleen, liver, mesenteric lymph nodes and adipose tissue was inhibited in ob/ob mice compared with their heterozygote littermates, ob/? mice. CCL2 expression in the adipose tissue of ob/? mice was enhanced by L. monocytogenes infection, different from ob/ob mice. Similarly, adiponectin expression was not observed in the adipose tissue of ob/ob mice. When mouse adipocyte 3T3-F442A-derived adipocytes were infected with L. monocytogenes, CCL2 expression was transiently up-regulated, following up-regulation of adiponectin expression. Up-regulation of CCL2 in adipocytes by L. monocytogenes infection was suppressed by knocked-down of adiponectin expression and supplementation of recombinant adiponectin partially recovered CCL2 expression. These results suggest that adiponectin is required for appropriate expression of CCL2 that is important for macrophage recruitment in response to bacterial infection.

Malignant edema in postpartum dairy cattle.

Five cases of postparturient vulvovaginitis and metritis in cattle caused by Clostridium septicum (malignant edema) are described in the current report. The diagnosis was established based on detection of C. septicum by culture and fluorescent antibody test. All animals were Holsteins, and 4 were primiparous (the parity of 1 animal was not reported). All animals developed clinical signs 1-3 days after calving, consisting of swelling of perineal and perivulvar areas, fever, and depression. Perineal, perivulvar, and perivaginal gelatinous and often hemorrhagic edema was consistently observed on gross examination. Longitudinal vulvar, vaginal, cervical, and uterine body tears, covered by fibrinous exudates, were also present. Microscopically, vulvar, vaginal, and uterine mucosae were multifocally necrotic and ulcerated. Large Gram-positive rods, some with subterminal spores, were present within the edematous subcutaneous and submucosal tissues. Clostridium septicum was demonstrated by culture and/or fluorescent antibody test in tissues of most animals. These cases of malignant edema were considered to be produced by C. septicum and predisposed by the trauma occurring during parturition.