S0514 Growth Hormone Normalizes Gastrointestinal Symptoms in mTBI Patients

Abstract

INTRODUCTION: Chronic inflammatory processes secondary to brain trauma have been hypothesized to significantly alter gastrointestinal metabolism, motility, and microbiome composition in patients with mild traumatic brain injuries (mTBI). This may be exacerbated by pituitary dysfunction and decreased growth hormone (GH) secretion resulting from injury. In this clinical trial, we analyzed the effects of GH treatment on gastrointestinal symptoms experienced by patients with concurrent mTBI and abnormal GH secretion. METHODS: Adult patients with mTBI and peak GH levels of < 10 ng/mL following glucagon stimulation test (n = 10) were given 0.6 mg injections of recombinant human growth hormone (rhGH) daily over a 6 month period. These patients were matched with healthy household controls (HHC) with whom they resided and shared meals with for comparison (Table 1). The Gastrointestinal Symptom Rating Scale (GSRS) measuring constipation, diarrhea, indigestion, abdominal pain, and acid reflux was administered to mTBI subjects (n = 10) and their healthy household controls (HHC; n = 10) every month for 6 months. RESULTS: GSRS scores within the treatment group dropped significantly after only one month of GH treatment (Figure 1, P < 0.01). Although GSRS scores were higher than the HCCs at baseline, the GSRS score of mTBI patients did not differ from the HHCs after receiving GH therapy. GSRS scores of the HHCs did not change significantly throughout the duration of the study (P > 0.05). CONCLUSION: Growth hormone may play a novel role in altering relationships in the gut-brain axis. Our results suggest that GH treatment helps to reduce a myriad of gastrointestinal symptoms in mTBI patients. We speculate this improvement may be attributable to changes in gut flora and overall gut microenvironment in mTBI, resembling that of healthy controls. Future studies can characterize the bacterial composition of gastrointestinal microbiomes of mTBI patients pre- and post-hormone supplementation compared to healthy controls to confirm this hypothesis.Table 1.: Demographics for healthy household controls and mTBI patients enrolled in the study (n = 20) a- Fisher's exact test; b- Parametric unpaired t-testFigure 1.: Gastrointestinal symptoms as measured by the Gastrointestinal Symptom Rating Scale (GSRS) in mTBI patients receiving 6 months of growth hormone treatment compared to matched healthy household controls.