A Distinct Gut Microbiota Exists Within Crohn's Disease-Related Perianal Fistulae.

BACKGROUND: Gut bacteria are strongly suspected to play a key role in the pathogenesis of Crohn's disease (CD). Studies have demonstrated alterations in the gut microbiota in this patient population. The purpose of this study was to characterize the gut microbiota of fistulizing perianal CD. MATERIALS AND METHODS: Stool and fistula samples were obtained from patients undergoing surgery for CD-related anorectal fistulae. Microbial compositions of matched stool and fistula samples were characterized using 16S rRNA gene profiling. The effect of sample type, patient gender, disease classification (Montreal A/B), disease activity (Harvey Bradshaw Index), antibiotic use, and presence of active proctitis on microbial composition was assessed. RESULTS: Samples were obtained from 18 patients. Bacteroides was the most abundant genera across all samples collected, followed by Streptococcus and Bifidobacterium. Bifidobacterium was present at significantly higher levels in fecal samples than fistula samples, whereas Achromobacter and Corynebacterium were present at significantly higher levels in fistula samples. Antibiotic, but not thiopurine or antitumor necrosis factor medication, exposure affected the gut microbial composition. Patient gender, disease classification, disease activity, and presence of active proctitis did not alter stool or fistula microbiota. CONCLUSIONS: Our data show that the gut microbiota within CD-related anorectal fistulae is distinct from that in stool samples obtained from the same patients. We also observe a dysbiosis in patients treated with antibiotics compared with those not treated with antibiotics.

MC1R gene polymorphisms are associated with dysfunctional immune responses and wound infection after burn injury.

BACKGROUND: Systemic inflammatory response syndrome (SIRS) is associated with organ failure and infectious complications after major burn injury. Recent evidence has linked melanocortin signaling to anti-inflammatory and wound-repair functions, with mutations in the melanocortin 1 receptor (MC1R) gene leading to increased inflammatory responses. Our group has previously demonstrated that MC1R gene polymorphisms are associated with postburn hypertrophic scarring. Thus, we hypothesized that MC1R single nucleotide polymorphisms (SNPs) would be associated with increased burn-induced SIRS and increased infectious complications. METHODS: We performed a retrospective cohort study of adults (>18 y of age) admitted to our burn center with >20% total body surface area (TBSA) partial/full thickness burns between 2006 and 2013. We screened for five MC1R SNPs (V60L, V92M, R151C, R163Q, T314T) by polymerase chain reaction from genomic DNA isolated from blood samples. We performed a detailed review of each patient chart to identify age, sex, race, ethnicity, %TBSA burned, burn wound infections (BWIs), and 72-hr intravenous fluid volume, the latter a surrogate for a dysfunctional inflammatory response to injury. Association testing was based on multivariable regression. RESULTS: Of 106 subjects enrolled, 82 had complete data for analysis. Of these, 64 (78%) were male, with a median age of 39 and median burn size of 30% TBSA. A total of 36 (44%) subjects developed BWIs. The median total administered IV crystalloid in first 72h was 24.6 L. In multivariate analysis, the R151C variant allele was a significant independent risk factor for BWI (adjusted prevalence ratio 2.03; 95% CI: 1.21-3.39; P = 0.007), and the V60L variant allele was independently associated with increased resuscitation fluid volume (P = 0.021). CONCLUSIONS: This is the first study to demonstrate a significant association between genetic polymorphisms and a nonfatal burn-induced SIRS complication. Our findings suggest that MC1R polymorphisms contribute to dysfunctional responses to burn injury that may predict infectious and inflammatory complications.

Effects of Colorectal Cancer Risk Factors on the Association Between Aspirin and Colorectal Cancer.

BACKGROUND/AIM: We investigated the effect of aspirin on colorectal cancer (CRC) risk among subgroups of women with and without risk factors for CRC. PATIENTS AND METHODS: Using data from the Women's Health Initiative, we estimated hazard ratios for CRC in association with aspirin use, with stratifications by cardiovascular disease (CVD) risk status, family history of CRC, and history of colorectal polypectomy. RESULTS: Aspirin was associated with a lower risk of CRC among women with low/normal or high CVD-risk status; no family history of CRC; or a history of colonoscopy with polypectomy. Aspirin was not associated with CRC among women with a family history of CRC or a history of colonoscopy without polypectomy. CONCLUSION: Aspirin was associated with a lower risk of CRC in women at all levels of CVD-risk, in those with a history of colonoscopy with polypectomy, and in those without a family history of CRC.

Melanocortin-1 Receptor Polymorphisms and the Risk of Complicated Sepsis After Trauma: A Candidate Gene Association Study.

OBJECTIVE: The aim of the study was to determine if melanocortin-1 receptor (MC1R) single nucleotide polymorphisms (SNPs) are associated with complicated sepsis after trauma. BACKGROUND: Nosocomial infections are an important cause of morbidity and mortality after trauma. Several SNPs in inflammation-related genes have been associated with sepsis. MC1R is an anti-inflammatory mediator that may be involved in the immune response after trauma. PATIENTS AND METHODS: We genotyped eight common MC1R SNPs in genomic DNA from subjects enrolled in a previously reported prospective cohort study. Subjects were adult trauma patients admitted to the intensive care unit at a Level 1 trauma center (2003-2005). RESULTS: A total of 1,246 subjects were included in the analysis. The majority were male (70%), severely injured (81%), and injured by a blunt mechanism (89%). Forty percent developed sepsis, and 23% developed complicated sepsis, which was defined as sepsis with organ dysfunction. In logistic regression analysis, with adjustments for age, sex, body mass index, injury severity score, red blood cell transfusion requirement, and mechanism of injury, the MC1RR163Q variant (rs885479) was associated with a lower risk of developing complicated sepsis (adjusted odds ratio [ORadj] = 0.48, 95% confidence interval [CI]: 0.28-0.81, P = 0.006). In a subgroup of 511 subjects with genome-wide SNP data, the association between the MC1RR163Q variant and complicated sepsis remained significant after adjusting for genetic substructure (by principal components) and the above clinical factors (ORadj = 0.30, 95% CI: 0.13-0.70, P = 0.005). CONCLUSIONS: MC1RR163Q is associated with a lower risk of complicated sepsis after trauma. Therapeutic targeting of MC1R may be beneficial for trauma patients at risk for complicated sepsis.

Dermal Fibroblasts from the Red Duroc Pig Have an Inherently Fibrogenic Phenotype: An In Vitro Model of Fibroproliferative Scarring.

BACKGROUND: The pathophysiology of hypertrophic scarring is unknown in part because of the lack of a robust animal model. Although the red Duroc pig has emerged as a promising in vivo model, the cellular mechanisms underlying Duroc scarring are unknown, and the size and cost of Duroc pigs are obstacles to their use. Given the central role of the dermal fibroblast in scarring, the authors hypothesized that dermal fibroblasts from the Duroc pig exhibit intrinsic differences in key aspects of the fibroblast response to injury compared with those from the Yorkshire pig, a same-species control that heals normally. METHODS: Duroc and Yorkshire dermal fibroblasts were isolated from uninjured dorsal skin. Actin stress fibers and focal adhesions were visualized by immunocytochemistry and transmission electron microscopy. Cell migration was measured using a scratch wound-closure assay. Contractile function was assessed by collagen gel contraction. Expression of scarring-related genes was determined by quantitative real-time reverse-transcriptase polymerase chain reaction, and transforming growth factor (TGF)-ß1 protein expression was determined by Western blotting. RESULTS: Duroc dermal fibroblasts display increased adhesion-complex formation, impaired migration, enhanced collagen contraction, and profibrotic gene and protein expression profiles compared with Yorkshire fibroblasts at baseline. In addition, Duroc fibroblasts overexpressed TGF-ß1 and were less responsive to exogenous TGF-ß1. CONCLUSIONS: Duroc dermal fibroblasts have inherent myofibroblastic differentiation that may account for the pathologic scarring in these animals. The authors' data further validate the Duroc model and support Duroc fibroblast cell culture as a simple, inexpensive, reproducible, and biologically tractable in vitro model for the study of fibroproliferative scarring.