Neuropathological features of pediatric laryngomalacia.

OBJECTIVE: Laryngomalacia is the most common pediatric laryngeal anomaly. The pathophysiology of laryngomalacia is not well defined; the leading hypothesis suggests weak laryngeal tone and neuromuscular discoordination. Only a few studies explored the histopathology of the laryngeal submucosal nerves, with reported nerve hypertrophy. Our study aims to describe the histopathology of submucosal nerves in specimens obtained from children with severe laryngomalacia compared to pediatric cadaveric controls. STUDY DESIGN: Prospective study. SETTINGS: Tertiary care children's hospital. METHODS: Histologic and immunohistochemical sections of supraglottic tissue from 26 children with severe laryngomalacia and six pediatric autopsies were digitally scanned and assessed with image analysis software (QuPath), resulting in the identification and measurement of 4561 peripheral nerves and over 100,000 foci of neurofilaments. RESULTS: Chronic inflammation was noted in all patients. Eosinophils were rare. The mean nerve area and perimeter were significantly smaller for patients with laryngomalacia compared to the control group (1594.0 ± 593.2 µm^2 vs. 2612.1 ± 2824.0 µm^2, p < 0.0001, and 158.8 ± 30.3 µm vs. 217.6 ± 165.0 µm, p < 0.0001). Nerve-per-area unit was significantly greater for patients with laryngomalacia compared to controls (1.39E-05 vs. 6.19 E-06, p = 0.009). The mean area and the number of neurofilaments per total nerve area were similar. Immunohistochemistry for calretinin, a marker for intestinal ganglion cells in Hirschsprung disease, was absent from all specimens. CONCLUSIONS: This series includes a comparison of all identifiable nerve fibers obtained from children with severe laryngomalacia and shows that the mucosal nerves are smaller on average than controls. These findings fail to provide support for significant morphologic peripheral nerve pathology in laryngomalacia.

Applications of Preoperative and Intraoperative Technologies for Complex Primary and Secondary Facial Trauma Reconstruction.

This article provides a review of the current technologies available in the preoperative and intraoperative management of complex and secondary maxillofacial trauma reconstruction. These patients present a unique challenge for which the advancement of imaging technologies, patient-specific modeling and implants, and intraoperative imaging and navigation can play an important role to improve their post-treatment outcomes.

Patient perception of medial patellofemoral ligament reconstruction on Instagram.

To date, there is limited social media evaluation of patients after medial patellofemoral ligament (MPFL) reconstruction and analysis of their perceived surgical outcome. The purpose of this study was to examine patient perceived outcomes after MPFL reconstruction via social media analysis on Instagram. A total of 486 posts containing "#MPFL" were included in the assessment. The tone of the post was examined in relation to demographic variables and the content of the post. When comparing posts containing positive vs. negative tone, those referencing rehabilitation (P < 0.0001) and activities of daily living (ADLs) (P = 0.0002) were more likely to be positive. Posts referencing surgical incision or scar (P = 0.02) or postoperative instability/dislocation (P < 0.0001) were more likely to have a negative tone. Multivariable logistic regression identified references to incision/scar (odds ratio [OR]: 0.446, P = 0.0264) and instability/dislocation (OR: 0.071, P < 0.0001) as strong negative predictors of positive tone. However, referencing rehabilitation (OR: 2.464, P = 0.0091) or ADLs (OR: 2.251, P = 0.0187) substantially increased the likelihood of a positive post tone. In conclusion, positive tone was associated with improved rehabilitation and ability to perform ADLs postoperatively. In contrast, negative tone was associated with dissatisfaction with the scar/incision, as well as postoperative patellar instability.

Altered pancreas remodeling following glucose intolerance in pregnancy in mice.

Gestational diabetes mellitus increases the risk of dysglycemia postpartum, in part, due to pancreatic ß-cell dysfunction. However, no histological evidence exists comparing endocrine pancreas after healthy and glucose-intolerant pregnancies. This study sought to address this knowledge gap, in addition to exploring the contribution of an inflammatory environment to changes in endocrine pancreas after parturition. We used a previously established mouse model of gestational glucose intolerance induced by dietary low protein insult from conception until weaning. Pancreas and adipose samples were collected at 7, 30 and 90 days postpartum for histomorphometric and cytokine analyses, respectively. Glucose tolerance tests were performed prior to euthanasia and blood was collected via cardiac puncture. Pregnant female mice born to dams fed a low protein diet previously shown to develop glucose intolerance at late gestation relative to controls continued to be glucose intolerant until 1 month postpartum. However, glucose tolerance normalized by 3 months postpartum. Glucose intolerance at 7 days postpartum was associated with lower beta- and alpha-cell fractional areas and higher adipose levels of pro-inflammatory cytokine, interleukin-6. By 3 months postpartum, a compensatory increase in the number of small islets and a higher insulin to glucagon ratio likely enabled euglycemia to be attained in the previously glucose-intolerant mice. The results show that impairments in endocrine pancreas compensation in hyperglycemic pregnancy persist after parturition and contribute to prolonged glucose intolerance. These impairments may increase the susceptibility to development of future type 2 diabetes.

Interrupted Glucagon Signaling Reveals Hepatic α Cell Axis and Role for L-Glutamine in α Cell Proliferation.

Decreasing glucagon action lowers the blood glucose and may be useful therapeutically for diabetes. However, interrupted glucagon signaling leads to α cell proliferation. To identify postulated hepatic-derived circulating factor(s) responsible for α cell proliferation, we used transcriptomics/proteomics/metabolomics in three models of interrupted glucagon signaling and found that proliferation of mouse, zebrafish, and human α cells was mTOR and FoxP transcription factor dependent. Changes in hepatic amino acid (AA) catabolism gene expression predicted the observed increase in circulating AAs. Mimicking these AA levels stimulated α cell proliferation in a newly developed in vitro assay with L-glutamine being a critical AA. α cell expression of the AA transporter Slc38a5 was markedly increased in mice with interrupted glucagon signaling and played a role in α cell proliferation. These results indicate a hepatic α islet cell axis where glucagon regulates serum AA availability and AAs, especially L-glutamine, regulate α cell proliferation and mass via mTOR-dependent nutrient sensing.