Gut Microbiota Dysbiosis Associated with Persistent Fatigue in Hematopoietic Cell Transplantation Survivors.

Fatigue is one of the most prevalent and distressing complications among hematopoietic stem cell transplantation (HCT) survivors, negatively affecting physical, social, and emotional domains of quality of life. Chronic systemic inflammation has been linked to alterations in nervous system activity and initiation of distressing symptoms, such as fatigue. Damage to gut mucosa due to alteration in gut microbiota (GM) composition and microbial translocation has been shown to increase systemic proinflammatory cytokines. The aim of this study was to evaluate the relationship between fatigue and GM by measuring the differences in GM composition in HCT survivors with and without persistent fatigue. This cross-sectional study included 30 adults who underwent HCT for a hematologic disease and were at least 1 year post-HCT. Patients with chronic graft-versus-host disease were excluded. Fatigue severity was assessed by the Brief Fatigue Inventory (BFI). Based on the BFI score, patients were grouped into 2 categories: 0 to 3 (without fatigue) and ≥4 (with fatigue). The V1 to V3 region of the 16S rRNA gene from fecal specimens was sequenced using the Illumina MiSeq. Sequencing reads were processed, denoised, and replicated, chimeras were filtered, amplicon sequence variants (ASVs) were generated, and taxonomy was assigned using DADA2. Beta diversity analysis through principal coordinate analysis was generated using the Bray-Curtis dissimilarity matrix, and the difference was tested using linear model with generalized least squares in R. An alpha diversity analysis was performed using Chao1. Linear discriminant analysis effect size (LEfSe) was used to find markers that differ between the 2 groups. Based on the BFI results, patients were categorized into 2 cohorts: with fatigue (n = 14) and without fatigue (n = 16). The 2 cohorts were similar in terms of demographics, disease, and transplant characteristics. Based on the GM analysis, there was a significant difference in GM composition (beta diversity) between the 2 cohorts (P = .001). Alpha diversity (richness) was also significantly lower in survivors with fatigue (P =.002). LEfSe analysis identified 46 discriminative features (P < .05; linear discriminant analysis score >2) whose relative abundance varied significantly among individuals with fatigue and those without fatigue. Ten ASVs were associated with the patients with fatigue, and 36 ASVs were associated with those without fatigue. Several ASVs enriched in survivors with fatigue included organisms such as Klebsiella and Enterococcus, which have been implicated in inflammatory bowel diseases. The ASVs enriched in the cohort without fatigue were members of the Ruminococcaceae family (Oscillospira spp) and the Lachnospiraceae family (Fusicatenibacter and Coprococcus spp), which are known to have the ability to ferment complex plant carbohydrates. These findings show an association between GM composition and fatigue and suggest a microbial contribution to clinically significant fatigue post-HCT, which may guide the development of new approaches to treating fatigue based on manipulation of the GM.

Dietary Intake and Diet Quality of Hematopoietic Stem Cell Transplantation Survivors.

Hematopoietic stem cell transplantation (HCT) survivors are burdened by a high prevalence and early onset of chronic diseases. Healthy dietary patterns have been associated with lower risks of chronic health conditions in the general population. HCT survivors are susceptible to multiple complications that may result in chronic illness. Unfortunately, no study to date has comprehensively documented the adherence of HCT survivors to the Dietary Guidelines for Americans (DGA), which are designed specifically to provide guidance for making healthy food choices. The primary aim of this study was to evaluate diet quality and nutrient intake adequacy of HCT survivors. A secondary aim was to assess these survivors' willingness to take part in a future dietary intervention. The dietary intake of adults who had undergone autologous or allogeneic HCT for a hematologic disease and were at least 1 year post-transplantation was assessed using the Block 2014 food frequency questionnaire, and diet quality was estimated using the Healthy Eating Index 2015. Nutrient intake adequacies of the group were estimated by the estimated average requirement cutpoint method. Survivors' (n = 90) HEI-2015 scores averaged 61.6 ± 1.1. Adherence to a good-quality diet was reported by only 10% of survivors. Intakes of vitamins A, C, and D, as well as magnesium and calcium, suggested inadequacy. Fiber intake at 8.9 g per 1000 kcal/day fell below the recommended adequate intake. "Change in taste" was associated with lower quality of diet (P = .02). HCT survivors within 2 years post-transplantation were more receptive than survivors beyond 2 years to participating in a dietary intervention (95% versus 65%; P = .0013). Adult HCT survivors reported less-than-optimal adherence to the 2015-2020 DGA and had numerous shortfall nutrient intakes; however, their willingness to participate in a dietary intervention was relatively high. These findings reinforce the need to incorporate nutrition into HCT survivor care.