Gut microbiota and short-chain fatty acid alterations in cachectic cancer patientsOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This clinical study asked whether cancer cachexia, the wasting syndrome of weight and muscle loss, is linked to gut microbiome and metabolite changes in humans. Prior evidence came only from animals. Stool samples were profiled by 16S rRNA V4 sequencing. Short-chain fatty acids were quantified by gas chromatography, and intestinal inflammation was assessed with fecal calprotectin, serum C-reactive protein, and leucocyte counts.
Who was studied?
The study enrolled 107 human cancer patients and 76 healthy household partners as controls with similar diet and lifestyle. Patients had pancreatic, breast, lung, or ovarian cancer and were sampled at diagnosis before therapy. Patients losing more than 5% body weight over 6 months were classed as cachectic (33 patients); 74 were non-cachectic. Cachexia was most common in pancreatic cancer (66.7%), then ovarian (25%), lung (20.8%), and breast cancer (17.3%).
What were the most important findings?
Overall microbial diversity did not differ between groups, but specific taxa did. The phylum Proteobacteria was significantly more abundant in cachectic patients (p below 0.001), along with an unknown Enterobacteriaceae genus (p below 0.01) and Veillonella (p below 0.001). Megamonas and Peptococcus also differed, and Enterobacteriaceae plus Veillonella correlated positively with weight loss. Total fecal short-chain fatty acids tended to be lower in cachexia, and acetate was significantly reduced (p below 0.05), driven mainly by pancreatic cancer patients. Fecal calprotectin correlated with Peptococcus, Enterobacteriaceae, and Veillonella but was not significantly elevated overall.
What are the greatest implications of this study?
These first human data suggest the gut microbiome may be a therapeutic target in cancer cachexia, echoing animal findings of Proteobacteria expansion and lower acetate. Reduced acetate could relate to the metabolic disturbances of wasting. The bacterial and metabolite signatures may eventually help identify or monitor cachexia. Because the cachectic group was mostly pancreatic cancer and staging differed, effects may reflect tumor type or stage rather than cachexia itself, and cachexia was defined only by self-reported weight loss.