Muscle wasting is a decline in skeletal muscle mass and function that is associated with aging, obesity, and a spectrum of pathologies including cancer. Cancer-associated wasting not only reduces quality of life, but also directly impacts cancer mortality, chemotherapeutic efficacy, and surgical outcomes. There is an incomplete understanding of the role of tumor-derived factors in muscle wasting and sparse knowledge of how these factors impact in vivo muscle regeneration. Here, we identify several cytokines/chemokines that negatively impact in vitro myogenic differentiation. We show that one of these cytokines, CXCL1, potently antagonizes in vivo muscle regeneration and interferes with in vivo muscle satellite cell homeostasis. Strikingly, CXCL1 triggers a robust and specific neutrophil/M2 macrophage response that likely underlies or exacerbates muscle repair/regeneration defects. Taken together, these data highlight the pleiotropic nature of a novel tumor-derived cytokine and underscore the importance of cytokines in muscle progenitor cell regulation.

Background From both a medical and surgical perspective, obese breast cancer patients are considered to possess higher risk when undergoing autologous breast reconstruction relative to nonobese patients. However, few studies have evaluated the continuum of risk across the full range of obesity. This study sought to compare surgical risk between the three World Health Organization (WHO) classes of obesity in patients undergoing deep inferior epigastric perforator (DIEP) flap breast reconstruction. Methods A retrospective review of 219 obese patients receiving 306 individual DIEP flaps was performed. Subjects were stratified into WHO obesity classes I (body mass index [BMI]: 30–34), II (BMI: 35–39), and III (BMI: ≥ 40) and assessed for risk factors and postoperative donor and recipient site complications. Results When examined together, the rate of any complication between the three groups only trended toward significance (p = 0.07), and there were no significant differences among rates of specific individual complications. However, logistic regression analysis showed that class III obesity was an independent risk factor for both flap (odds ratio [OR]: 1.71, 95% confidence interval [CI]: 0.91–3.20, p = 0.03) and donor site (OR: 2.34, 95% CI: 1.09–5.05, p = 0.03) complications. Conclusion DIEP breast reconstruction in the obese patient is more complex for both the patient and the surgeon. Although not a contraindication to undergoing surgery, obese patients should be diligently counseled regarding potential complications and undergo preoperative optimization of health parameters. Morbidly obese (class III) patients should be approached with additional caution, and perhaps even delay major reconstruction until specific BMI goals are met.

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Background: The deep inferior epigastric perforator flap (DIEP) is a widely known reliable option for autologous breast reconstruction. One common complication of DIEP procedures is fat necrosis. Consequences of fat necrosis include wound healing complications, pain, infection, and the psychological distress of possible cancerous recurrence. Clinical judgment alone is an imperfect method to detect at-risk segments of adipose tissue. Objective methods to assess perfusion may improve fat necrosis complication rates, reducing additional surgeries to exclude cancer and improve cosmesis for patients. Methods: The authors performed a retrospective review of patients who underwent analysis of DIEP flap vascularity with or without intraoperative indocyanine green angiography (ICGA). Flap perfusion was assessed using intravenous ICGA and was quantified with both relative and absolute value units of fluorescence. Tissue with observed values less than 25% to 30% relative value units was resected. Postoperative outcomes and fat necrosis incidence were collected. Results: Three hundred fifty-five DIEP flaps were included in the study, 187 (52.7%) of which were assessed intraoperatively with ICGA. Thirty-nine patients (10.9%) experienced operable fat necrosis. No statistically significant difference in incidence of postoperative fat necrosis was found between the 2 groups ( P = 0.732). However, a statistically significant relationship was found between fat necrosis incidence and body mass index as both a continuum ( P = 0.001) and when categorized as greater than 35 ( P = 0.038). Conclusions: Although ICGA is useful for a variety of plastic surgery procedures, our retrospective review did not show a reduction in operable fat necrosis when using this technology.