Presence of Increased Mast Cells in Infants and Children with Volume and Variety Limited Intake

Background: Reports indicate patients with feeding difficulties demonstrate signs of inflammation on biopsies, notably eosinophilia, but it is unknown whether mast cell density contributes to variety or volume limitation symptoms. The aim of our study was to evaluate eosinophil and mast cell density of EGD biopsies in pediatric patients with symptoms of decreased volume or variety of ingested foods. Methods: We conducted a single-center, retrospective chart review of EMRs for all new feeding clinic patients between 0 and 17 years of age. Patients were categorized by symptoms at the initial visit as well as eosinophil and mast cell densities in those with EGD biopsies. Ten patients were identified as controls. Results: We identified 30 patients each with volume and variety limitation. Antral mast cell density was increased in 32.1% of variety-limited patients, 37.5% of volume limited patients, and in no controls; Duodenal mast cell density was increased in 32.1% of variety-limited patients, 40.6% of volume-limited patients, and in no controls. Conclusions: In both variety- and volume-limited patients, antral and duodenal mast cell densities were increased. These associations warrant further investigation of the mechanism between mast cells and development of feeding difficulties, allowing more targeted pediatric therapies.

High Mast Cell Density Predicts a Favorable Prognosis in Patients with Pancreatic Neuroendocrine Neoplasms

Introduction: Mast cells are involved in allergic diseases, immune regulation, and tumor microenvironment modulation, with both pro- and anti-tumorigenic functions, and could serve as a prognostic factor in various cancers. However, their potential role in pancreatic neuroendocrine neoplasms (PanNENs) is largely unknown. Here, our aim was to investigate the presence of mast cells in PanNENs and evaluate their association with clinicopathological parameters and other common tumor-infiltrating immune cells. Methods: Tissue microarrays containing PanNEN samples from 187 patients were constructed and stained immunohistochemically for CD117, CD15, CD68, CD3, CD4, and CD8. Immune cells were counted from four high-power fields (HPFs; 400×) at maximal concentrations, and the mean counts were calculated per HPF. The cut-off values were set by X-tile. Results: The median (interquartile range) counts of CD117+ mast cells, CD15+ neutrophils, CD68+ macrophages, CD3+ T cells, and CD4+ T cells were 3.5 (2.0–6.0), 3.0 (1.3–6), 3.8 (2.5–5.8), 13 (8.0–24.0), 2.0 (1.0–4.0)/HPF, respectively. CD8+ T cells were not detected. The cut-off values for these immune cells were 1.5/HPF, 6/HPF, 4.8/HPF, 32.5/HPF, and 2/HPF, respectively. Low mast cell density was correlated with higher grades, non-insulinoma, and advanced stages. Moreover, high mast cell infiltration was associated with elevated CD4+ T cell and CD15+ neutrophil counts. Multivariate analysis revealed that high mast cell density was an independent predictor of prolonged progression-free survival in the entire cohort, in pancreatic neuroendocrine tumors, and in intermediate-grade, non-insulinoma, and advanced stage subgroups. Conclusions: These findings suggest a protective role of mast cells in PanNENs.

A Survey of Methodologies for Assessing Mast Cell Density and Activation in Patients with Functional Abdominal Pain Disorders

The aim was to assess methods utilized in assessing mast cell involvement in functional abdominal pain disorders (FAPDs), specifically to describe variability in methods utilized to assess both mast cell density and activation and determine if a consensus exists. After a literature search identified 70 manuscripts assessing mast cell density, data were extracted including FAPD diagnosis, site of biopsy, selection of microscopic fields analyzed, selection of mucosal region analyzed, method of mast cell identification, method to assess mast cell density, and if performed, method to assess mast cell activation. There appears to be some consensus favoring inmmunohistochemical stains over histochemical stains for identifying mast cells. Otherwise, considerable variability exists in methodology for assessing mast cell density and activation. Regardless of method, approximately 80% of studies found increased mast cell density and/or activation in comparison to controls with no method being superior. A wide variety of methods have been employed to assess mast cell density and activation with no well-established consensus and inadequate data to recommend specific approaches. The current methodology providing physiologic information needs to be translated to a standard methodology providing clinical information with the development of criteria establishing abnormal density and/or activation, and more importantly, predicting treatment response.

Immunohistochemical analysis of the arterial supply and mast cells of the trigeminal ganglion

The aim of this study was to quantify the distribution of microvessels and mast cells in all three parts of the trigeminal ganglion (TG). Statistical analyses were applied to investigate possible micromorphological regional differences in their density. Five serially sectioned human TGs were prepared for CD34 and mast cell tryptase immunostaining. The following quantifications were performed in microscopic fields of three parts of the TG: microvessel density (MVD), mast cell density (MCD) and ganglionic cell count. The density of CD34-positive microvessels was not significantly different in any of the three observed parts of the TG. The distribution of neurons showed no significant statistical difference in three parts of the TG. There was no difference in the density of tryptase-positive mast cells within the TG, but there was an abundant presence of mast cells in the periganglionic dural and subdural tissues, a finding hitherto not reported. We can say that there is a homogenous vascular pattern within the TG which excludes local predominance in pathogenesis of trigeminal neuralgia. Second, and more important, the finding of peri-trigeminal mast cells indicates their important role in migraine pain and confirms their degranulation as the main therapeutic goal for this condition.