Project description:A prospective, multicenter, cohort study was conducted in patients with severe obesity, who were randomized between two bariatric surgery techniques (Roux-en-Y gastric bypass and one anastomosis gastric bypass). Fecal samples were collected from 45 obese patients before surgery (T0) and 24 months after surgery (T1) and analyzed by shotgun metaproteomics.
Project description:Bariatric surgery is associated with improved breast cancer (BC) outcomes, including greater immunotherapy effectiveness in a pre-clinical BC model. A potential mechanism of bariatric surgery-associated protection is through the gut microbiota. Here, we demonstrate the dependency of improved immunotherapy response on the post-bariatric surgery gut microbiome via fecal microbial transplant. Cecal contents were isolated from either obese controls that received sham surgery or formerly obese mice following bariatric surgery-induced weight loss and transferred by FMT to lean recipients. Response to αPD-1 immunotherapy was significantly improved following FMT from formerly obese bariatric-surgery treated mice. Microbes can impact tumor burden through microbially derived metabolites produced or modified by gut microbiota including branched chain amino acids (BCAA). Circulating BCAA correlated significantly with NK T cell content in the tumor microenvironment in both donor mice after bariatric surgery and in FMT recipients of donor cecal content after bariatric surgery compared to obese sham controls. Findings implicate a role of microbially-derived BCAA in activating anti-tumor immunity that is dependent upon bariatric surgery. Importantly, when stool from a patient who exhibited 25% weight loss post-bariatric surgery was transplanted into recipient mice and compared to the patient’s pre-bariatric surgery stool transplant. Patient samples post bariatric surgery significantly reduced tumor burden by 2.4-fold and immunotherapy effectiveness was doubled. Taken together, findings suggest that reinvigorating anti-tumor immunity may be dependent upon microbially derived metabolites such as BCAA.
Project description:ImportanceExcess adiposity confers higher risk of breast cancer for women. For women who have lost substantial weight, it is unclear whether previous obesity confers residual increased baseline risk of breast cancer compared with peers without obesity.ObjectivesTo determine whether there is a residual risk of breast cancer due to prior obesity among patients who undergo bariatric surgery.Design, setting, and participantsRetrospective matched cohort study of 69 260 women with index date between January 1, 2010, and December 31, 2016. Patients were followed up for 5 years after bariatric surgery or index date. Population-based clinical and administrative data from multiple databases in Ontario, Canada, were used to match a cohort of women who underwent bariatric surgery for obesity (baseline body mass index [BMI] ≥35 with comorbid conditions or BMI ≥40) to women without a history of bariatric surgery according to age and breast cancer screening history. Nonsurgical controls were divided into 4 BMI categories (<25, 25-29, 30-34, and ≥35). Data were analyzed on October 21, 2021.ExposuresWeight loss via bariatric surgery.Main outcomes and measuresResidual hazard of breast cancer after washout periods of 1, 2, and 5 years. Comparisons were made between the surgical and nonsurgical cohorts overall and within each of the BMI subgroups.ResultsIn total, 69 260 women were included in the analysis, with 13 852 women in each of the 5 study cohorts. The mean (SD) age was 45.1 (10.9) years. In the postsurgical cohort vs the overall nonsurgical cohort (n = 55 408), there was an increased hazard for incident breast cancer in the nonsurgical group after washout periods of 1 year (hazard ratio [HR], 1.40 [95% CI, 1.18-1.67]), 2 years (HR, 1.31 [95% CI, 1.12-1.53]), and 5 years (HR, 1.38 [95% CI, 1.21-1.58]). When the postsurgical cohort was compared with the nonsurgical cohort with BMI less than 25, the hazard of incident breast cancer was not significantly different regardless of the washout period, whereas there was a reduced hazard for incident breast cancer among postsurgical patients compared with nonsurgical patients in all high BMI categories (BMI ≥25).Conclusions and relevanceFindings suggest that bariatric surgery was associated with a reduced risk of developing breast cancer for women with prior obesity equivalent to that of a woman with a BMI less than 25 and a lower risk when compared with all groups with BMI greater than or equal to 25.
Project description:Patients undergoing bariatric surgery are protected from subsequent breast cancer risk. It is unknown whether weight loss alone or surgery-specific alterations mediate risk reduction. We examined breast cancer in a pre-clinical model of diet induced obesity (DIO) followed by vertical sleeve gastrectomy (VSG) or dietary weight loss. DIO exacerbated tumor progression compared to lean controls, while VSG-induced weight loss reversed this exacerbation. However, dietary interventions were more effective than VSG despite similar reductions in weight and adiposity, potentially due to elevated immunosuppression after VSG. In tumor bearing mice, anti-PD-L1 immunotherapy after VSG improved anti-tumor immunity and potently impaired tumor progression. Thus, weight loss before tumor onset was protective regardless of intervention. Importantly, immunotherapy specifically improved outcomes in VSG.
Project description:Obesity is a complex metabolic condition considered a worldwide public health crisis, and a deeper mechanistic understanding of obesity-associated diseases is urgently needed. Obesity comorbidities include many associated cancers and are estimated to account for 20% of female cancer deaths in the USA. Breast cancer, in particular, is associated with obesity and is the focus of this review. The exact causal links between obesity and breast cancer remain unclear. Still, interactions have emerged between body mass index, tumor molecular subtype, genetic background, and environmental factors that strongly suggest obesity influences the risk and progression of certain breast cancers. Supportive preclinical research uses various diet-induced obesity models to demonstrate that weight loss, via dietary interventions or changes in energy expenditure, reduces the onset or progression of breast cancers. Ongoing and future studies are now aimed at elucidating the underpinning mechanisms behind weight-loss-driven observations to improve therapy and outcomes in patients with breast cancer and reduce risk. This review aims to summarize the rapidly emerging literature on obesity and weight loss strategies with a focused discussion of bariatric surgery in both clinical and preclinical studies detailing the complex interactions between metabolism, immune response, and immunotherapy in the setting of obesity and breast cancer.
Project description:Bariatric surgery mediated weight loss has been shown to significantly reduce breast cancer incidence in women. We hypothesize that loss of excessive adiposity, reduces net Estrogen Receptor Alpha activation which in turn lowers breast cancer risk. A differential gene expression analysis and subsequent pathway enrichment analysis would reveal the relevant molecular mechanism behind the preventive effect of weight loss. We will correlate our RNASeq data findings with serum and breast tissue concentration of hormones as well as expression of proteins regulating hormone synthesis in breast. For this study, we recruited 30 patients who were prescribed baritaric surgery and met our selection criteria (no familial or personal history of breast cancer and free of other confounding conditions). Breast tissue and blood was collected at the day of surgery and at follow up after the patient lost 25% excess body weight. The breast core biopsy was preserved in RNALater till rna isolation and library preparation.