Associations of Mucosal Nerve Fiber Innervation Density with Hirschsprung-Associated Enterocolitis: A Retrospective Three-Center Cohort Study.

OBJECTIVE: Hirschsprung's disease (HSCR) is a congenital intestinal neurodevelopmental disorder characterized by the absence of enteric ganglion cells in the distal colon. Although Hirschsprung-associated enterocolitis (HAEC) is the most frequent life-threatening complication in HSCR, to date reliable biomarkers predicting the likelihood of HAEC are yet to be established. We established a three-center retrospective study including 104 HSCR patients surgically treated between 1998 and 2019. MATERIALS AND METHODS: Patient-derived cryopreserved or paraffin-preserved colonic tissue at surgery was analyzed via ßIII-tubulin immunohistochemistry. We subsequently determined extrinsic mucosal nerve fiber density in resected rectosigmoid specimens and classified HSCR patients accordingly into nerve fiber-high or fiber-low groups. We compared the distribution of clinical parameters obtained from medical records between the fiber-high (n = 36) and fiber-low (n = 68) patient groups. We assessed the association between fiber phenotype and enterocolitis using univariate and multivariate logistic regression adjusted for age at operation. RESULTS: Enterocolitis was more prevalent in patients with sparse mucosal nerve fiber innervation (fiber-low phenotype, 87%) compared with the fiber-high phenotype (13%; p = 0.002). In addition, patients developing enterocolitis had a younger age at surgery (3 vs. 7 months; p = 0.016). In the univariate analysis, the odds for enterocolitis development in the fiber-low phenotype was 5.26 (95% confidence interval [CI], 1.67-16.59; p = 0.005) and 4.01 (95% CI, 1.22-13.17; p = 0.022) when adjusted for age. CONCLUSION: Here, we showed that HSCR patients with a low mucosal nerve fiber innervation grade in the distal aganglionic colon have a higher risk of developing HAEC. Consequently, histopathologic analysis of the nerve fiber innervation grade could serve as a novel sensitive prognostic marker associated with the development of enterocolitis in HSCR patients.

Lack of Mucosal Cholinergic Innervation Is Associated With Increased Risk of Enterocolitis in Hirschsprung's Disease.

BACKGROUND & AIMS: Hirschsprung's disease (HSCR) is a congenital intestinal motility disorder defined by the absence of enteric neuronal cells (ganglia) in the distal gut. The development of HSCR-associated enterocolitis remains a life-threatening complication. Absence of enteric ganglia implicates innervation of acetylcholine-secreting (cholinergic) nerve fibers. Cholinergic signals have been reported to control excessive inflammation, but the impact on HSCR-associated enterocolitis is unknown. METHODS: We enrolled 44 HSCR patients in a prospective multicenter study and grouped them according to their degree of colonic mucosal acetylcholinesterase-positive innervation into low-fiber and high-fiber patient groups. The fiber phenotype was correlated with the tissue cytokine profile as well as immune cell frequencies using Luminex analysis and fluorescence-activated cell sorting analysis of colonic tissue and immune cells. Using confocal immunofluorescence microscopy, macrophages were identified in close proximity to nerve fibers and characterized by RNA-seq analysis. Microbial dysbiosis was analyzed in colonic tissue using 16S-rDNA gene sequencing. Finally, the fiber phenotype was correlated with postoperative enterocolitis manifestation. RESULTS: The presence of mucosal nerve fiber innervation correlated with reduced T-helper 17 cytokines and cell frequencies. In high-fiber tissue, macrophages co-localized with nerve fibers and expressed significantly less interleukin 23 than macrophages from low-fiber tissue. HSCR patients lacking mucosal nerve fibers showed microbial dysbiosis and had a higher incidence of postoperative enterocolitis. CONCLUSIONS: The mucosal fiber phenotype might serve as a prognostic marker for enterocolitis development in HSCR patients and may offer an approach to personalized patient care and new therapeutic options.

Predictors of impaired bone health in long-term survivors after allogeneic stem cell transplantation.

Survival after allogeneic stem cell transplantation (allo-HSCT) has improved, but so have long-term sequelae. We studied risk factors for fractures and impaired bone health in allo-HSCT patients in the Basel HSCT registry from 01/2003 to 12/2014 using cox proportional models adjusted for age, gender and Karnofsky Index. Our primary endpoint was the incidence of fractures. Out of 652 patients, 32 (5.0%) had a new fracture after transplantation (yearly incidence rate of 1.6%, 95% Confidence Interval [95%CI] 1.1-2.3%) and 325 (49.8%) had low bone mineral density (yearly incidence rate of 13.1%, 95%CI 11.6-14.8%), including 36.0% with osteopenia and 13.8% with osteoporosis. We found vitamin D deficiency during follow-up (Hazard Ratio [HR] 1.25, 95%CI 1.11-1.41, p < 0.001), hyperthyroidism before transplantation (HR 4.85, 95%CI 1.05-22.54, p = 0.044), cumulative years of immunosuppressant exposure (HR 1.23, 95%CI 1.07-1.41, p = 0.004 for steroidal and HR 1.09, 95%CI 1.01-1.18, p = 0.025 for non-steroidal drugs) and graft-versus-host disease (acute HR 1.24, 95%CI 1.11-1.40, p < 0.001; chronic HR 2.82, 95%CI 1.12-7.13, p = 0.028) to be significantly associated with fractures. Patients undergoing HSCT are at increased risk of fractures, which is associated with various disease and treatment-specific factors. Early identification of patients at risk may help to improve preventive measures.