Abstract Oral mucositis (OM) is a common debilitating dose-limiting toxicity of cancer treatment, including hematopoietic stem cell transplantation (HSCT). We hypothesized that the oral microbiome is disturbed during allogeneic HSCT, partially accounting for the variability in OM severity. Using 16S ribosomal RNA gene sequence analysis, metabolomic profiling, and computational methods, we characterized the behavior of the salivary microbiome and metabolome of 184 patients pre- and post-HSCT. Transplantation was associated with a decrease in oral α diversity in all patients. In contrast to the gut microbiome, an association with overall survival was not detected. Among 135 patients given methotrexate for graft-versus-host disease prophylaxis pre-HSCT, Kingella and Atopobium abundance correlated with future development of severe OM. Posttransplant, Methylobacterium species were significantly enriched in patients with severe OM. Moreover, the oral microbiome and metabolome of severe OM patients underwent distinct changes post-HSCT, compared with patients with no or mild OM. Changes in specific metabolites were well explained by microbial composition, and the common metabolic pathway was the polyamines pathway, which is essential for epithelial homeostasis. Together, our findings suggest that salivary microbial composition and metabolites are associated with the development of OM, offering new insights on pathophysiology and potential avenues of intervention.

Background: Prediabetes is a well-established risk factor for progression to overt diabetes mellitus (DM), which is in turn associated with development of hypertension (HTN) and vice versa. However, the role of prediabetes and HbA1c in particular as an independent risk factor for the development of hypertension is unclear.Aim: In this current study, we aimed to evaluate the association between both fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) levels in the prediabetes range and development of HTN among a large cohort of normotensive subjects. Design and methods:We investigated 5016 normotensive participants without DM and other cardiovascular risk factors who were annually screened in a tertiary medical center. Subjects were divided into normoglycemic and prediabetic groups. Normoglycemia was defined as HbA1c < 5.7% and FPG < 100 mg/dl. Prediabetes was defined according to the ADA criteria, i.e., 6.5% > HbA1c ≥ 5.7% or impaired fasting glucose (IFG):126 mg/dl > FPG ≥ 100 mg/ dl. Subgroup analysis was made by dividing participants into four groups according to FPG and HbA1C levels, i.e., normoglycemia, impaired HbA1c only, IFG only, and both parameters impaired.Results: During a follow-up of 3.7 ± 2.9 years, 318 (6.3%) subjects developed HTN. A cumulative hazard function for the development of hypertension showed a 2.89-fold ([95% CI 2.19-3.83], p < .0001) increased risk for HTN in the prediabetic population. In a multivariable Cox proportional hazard regression model adjusted to common confounding risk factors for HTN, prediabetes was found to be independently associated with a 1.95-fold ([95%, CI 1.43-2.52] p < .0001) increased risk for hypertension. Impaired HbA1C only was not found to be independently associated with HTN, while IFG only showed a 2.13-fold (95%, ] p < .0001) increased risk for HTN compared to normoglycemic, and a 2.55-fold ([95% CI 1.85-3.51] p < .0001) increased risk for HTN when both parameters impaired. Conclusion:Our study demonstrates that FPG in the prediabetes range, albeit not glycated hemoglobin, is independently and significantly associated with future development of HTN. Therefore, our findings further highlight the pivotal predictive role of IFG for HTN development as opposed to the limited independent role of abnormal HbA1c levels.

Background Oral mucositis (OM) is a common toxicity of stem cell transplantation (SCT). We sought to evaluate OM burden, risk factors, and implications in a cohort of allogeneic‐SCT recipients. Methods This was a single‐center study including 115 adult allogeneic‐SCT transplanted between 2016 and 2018 for various hematological conditions. Conditioning intensity was categorized as myeloablative (MAC, 39%), reduced intensity (34%), or reduced toxicity (RTC, 27%) in patients conditioned with fludarabine‐treosulfan. OM was prospectively graded using the Common Terminology Criteria for Adverse Events (v.4.0) system. Results Moderate‐to‐severe OM (grade 2‐4) was experienced by 60% of patients. In a univariate analysis, younger age (P = .023), lower body mass index (P = .01), recent smoking (P = .08), recent antibiotics exposure (P = .018), MAC (P < .001), and methotrexate (P = .009) were associated with moderate‐to‐severe OM. In a multivariable logistic regression model, conditioning and graft‐versus‐host disease prophylaxis remained significant. OM risk was lowest with RTC (RTC vs MAC: odd ratio [OR] 0.05, P < .001), and recent antibiotic exposure trended toward increased risk (OR 1.88, P = .168). OM was associated with longer hospitalization, delayed neutrophil engraftment, and gastrointestinal‐related infections. Conclusion Oral mucositis remains a leading SCT complication. Treosulfan‐based conditioning has low mucosal toxicity and is appealing given previous reports on its high efficacy.