Enteric Glia.

Enteric glia are a unique type of peripheral neuroglia that accompany neurons in the enteric nervous system (ENS) of the digestive tract. The ENS displays integrative neural circuits that are capable of governing moment-to-moment gut functions independent of input from the central nervous system. Enteric glia are interspersed with neurons throughout these intrinsic gut neural circuits and are thought to fulfill complex roles directed at maintaining homeostasis in the neuronal microenvironment and at neuroeffector junctions in the gut. Changes to glial functions contribute to a wide range of gastrointestinal diseases, but the precise roles of enteric glia in gut physiology and pathophysiology are still under examination. This review summarizes current concepts regarding enteric glial development, diversity, and functions in health and disease.

Duplex kidney: An incidental autopsy finding of clinical and medico-legal significance.

Duplex kidney, a rare congenital anomaly characterised by dual urinary drainage from the kidney, is typically discovered incidentally, often during radiological imaging or autopsy procedures. We report a case of a 21-year-old male who died from injuries sustained in a road traffic accident. The autopsy examination showed an incidental finding of duplex kidney on the left side. We discuss the clinical and potential medico-legal significance of duplex kidney which also has implications in renal transplantation. Notably, the presence of duplex kidney can potentially serve as an identifier in forensic investigations, given its rare incidence.

Diaphyseal giant cell tumour of mid-shaft tibia.

SummaryGiant cell tumours of bone are benign and locally aggressive tumours that usually occur in young adults and at the epiphysial locations after physeal closure. Occurrence outside of epiphysial locations and appearance in geriatric patients is rare. We report a case of a woman in her late 60s with a giant cell tumour of the mid-shaft of the right tibia. Extended curettage and biological reconstruction were performed with autologous double-barrel fibular struts and tri-cortical iliac crest bone grafting. At the 28-month follow-up examination, we noted full bony union at both ends with successful consolidation of the fibular struts, and importantly, no evidence of recurrence or other complications was observed.

Enteric glia regulate Paneth cell secretion and intestinal microbial ecology.

Glial cells of the enteric nervous system (ENS) interact closely with the intestinal epithelium and secrete signals that influence epithelial cell proliferation and barrier formation in vitro. Whether these interactions are important in vivo, however, is unclear because previous studies reached conflicting conclusions [1]. To better define the roles of enteric glia in steady state regulation of the intestinal epithelium, we characterized the glia in closest proximity to epithelial cells and found that the majority express PLP1 in both mice and humans. To test their functions using an unbiased approach, we genetically depleted PLP1+ cells in mice and transcriptionally profiled the small and large intestines. Surprisingly, glial loss had minimal effects on transcriptional programs and the few identified changes varied along the gastrointestinal tract. In the ileum, where enteric glia had been considered most essential for epithelial integrity, glial depletion did not drastically alter epithelial gene expression but caused a modest enrichment in signatures of Paneth cells, a secretory cell type important for innate immunity. In the absence of PLP1+ glia, Paneth cell number was intact, but a subset appeared abnormal with irregular and heterogenous cytoplasmic granules, suggesting a secretory deficit. Consistent with this possibility, ileal explants from glial-depleted mice secreted less functional lysozyme than controls with corresponding effects on fecal microbial composition. Collectively, these data suggest that enteric glia do not exert broad effects on the intestinal epithelium but have an essential role in regulating Paneth cell function and gut microbial ecology.

Human epidermal growth factor receptor 2/neu expression in urothelial carcinomas.

Introduction: Urothelial carcinomas of the bladder are more common in males, making them the sixth-most common cancer in men and the tenth-most common cancer overall, worldwide. Current guidelines do not recommend routine testing for human epidermal growth factor receptor (HER2/neu) expression on the biopsy specimens of patients with urothelial carcinoma. This study was aimed at determining the expression pattern of HER2/neu and its usefulness in muscle-invasive and nonmuscle-invasive urothelial carcinoma. Methods: HER2/neu expression was assessed in 89 specimens of urothelial cancer by immunohistochemistry (IHC), and equivocal cases were subjected to fluorescent in situ hybridization (FISH). Results: On IHC for HER2/neu, 17.9% (7/39) of the muscle-invasive bladder cancers (MIBCs) showed a 3+ expression, whereas 22% (11/50) of the non-muscle invasive cancers were positive with a score of 3+. A significant correlation between HER2/neu status and muscle invasion could not be established in the current study (P = 0.74, Fisher's exact test). Three cases of muscle-invasive (7.7%) and 2 cases (4%) among nonmuscle invasive cancers showed equivocal expression. All the cases with equivocal (2+) expression on IHC were subjected to FISH and none showed gene amplification on hybridization and were considered as negative. Conclusion: Overexpression of HER-2/neu was seen in 17.9% of MIBCs and 22% of non-MIBCs. There are no norms for routine testing of HER2/neu expression in the biopsy specimens of urothelial carcinoma. There is an unmet need to establish guidelines for HER2/neu scoring, similar to that for breast and gastric cancers, to determine the proportion of positive cases and help in identification of those who may benefit from targeted therapies.

Chronic neck pain in a child: a case of osteoblastoma of the C5 cervical vertebra.

Osteoblastoma is a primary bone-forming tumour that usually occurs in the second decade with an affinity to the posterior elements when found in the spine. Its occurrence in the early first decade is uncommon and often causes a diagnostic dilemma. It usually has a late presentation and the symptoms may be non-specific which may lead the clinician to overlook this particular entity. We present a case of osteoblastoma of the posterior elements of the C5 vertebra in a pre-adolescent child who was diagnosed and successfully managed with surgical resection in a timely fashion that led to favourable recovery postoperatively.

RET Signaling Persists in the Adult Intestine and Stimulates Motility by Limiting PYY Release From Enteroendocrine Cells.

BACKGROUND & AIMS: RET tyrosine kinase is necessary for enteric nervous system development. Loss-of-function RET mutations cause Hirschsprung disease (HSCR), in which infants are born with aganglionic bowel. Despite surgical correction, patients with HSCR often experience chronic defecatory dysfunction and enterocolitis, suggesting that RET is important after development. To test this hypothesis, we determined the location of postnatal RET and its significance in gastrointestinal (GI) motility. METHODS: RetCFP/+ mice and human transcriptional profiling data were studied to identify the enteric neuronal and epithelial cells that express RET. To determine whether RET regulates gut motility in vivo, genetic, and pharmacologic approaches were used to disrupt RET in all RET-expressing cells, a subset of enteric neurons, or intestinal epithelial cells. RESULTS: Distinct subsets of enteric neurons and enteroendocrine cells expressed RET in the adult intestine. RET disruption in the epithelium, rather than in enteric neurons, slowed GI motility selectively in male mice. RET kinase inhibition phenocopied this effect. Most RET+ epithelial cells were either enterochromaffin cells that release serotonin or L-cells that release peptide YY (PYY) and glucagon-like peptide 1 (GLP-1), both of which can alter motility. RET kinase inhibition exaggerated PYY and GLP-1 release in a nutrient-dependent manner without altering serotonin secretion in mice and human organoids. PYY receptor blockade rescued dysmotility in mice lacking epithelial RET. CONCLUSIONS: RET signaling normally limits nutrient-dependent peptide release from L-cells and this activity is necessary for normal intestinal motility in male mice. These effects could contribute to dysmotility in HSCR, which predominantly affects males, and uncovers a mechanism that could be targeted to treat post-prandial GI dysfunction.

Expression of Programmed Cell Death Ligand-1 and Mismatch Repair Status in Endometrial Carcinomas.

Background and Aims: Programmed death ligand-1 (PD-L1) is a co-regulatory molecule that suppresses local immunity, and mismatch repair (MMR) deficiency (dMMR) is reported to influence the response to anti-PD-L1-targeted therapy. This study was conducted to find the PD-L1 status, the occurrence of dMMR in endometrial carcinomas, and the association between them. Materials and Methods: The study included 35 resected specimens of endometrial carcinomas represented on formalin-fixed paraffin-embedded sections from January 2016 to July 2020. The clinicopathologic information including patient age, tumor histologic type, grade, stage, lymphovascular invasion, the extent of myometrial invasion, and the percentage of tumor-infiltrating lymphocytes (TILs) were obtained in all cases. The expression of PD-L1 and MMR antibodies including mutS homolog 2 (MSH-2), MSH-6, mutL homolog 1 (MLH-1) and MLH-3, and postmeiotic segregation 2 were assessed using immunohistochemistry. The statistical analysis was done using the Statistical Package for the Social Sciences (SPSS) version 26. Results: PD-L1 expression was noted in 48.6% of the cases in tumor cells and 65.7% of the cases in TILs and MMR was deficient in 28.6% of endometrial carcinomas. A statistically significant relation was noted between dMMR and TILs, PD-L1 expression in tumor cells and TILs, PD-L1 expression in tumor cells, and extent of myometrial invasion. Although there was no statistically significant association between MMR status and PD-L1 expression in tumor cells or TILs, 60% of patients with dMMR were PD-L1 positive. Conclusion: Sixty percent of dMMR cases showed PD-L1 expression in tumor cells. We conclude, ECs that are MMR deficient might get better response to anti-PD-L1 therapy. This study also revealed the prognostic use of TILs in PD-L1-expressed tumors.

Secretory carcinoma of parotid gland masquerading as acinic cell carcinoma on cytology: Case report and review of literature.

Secretory carcinoma is a relatively recently discovered low-grade salivary gland carcinoma with morphological similarities to its breast counterpart. The histopathological features of this entity are well established; however, the cytomorphological features are not well evaluated, leading to diagnostic challenges and pitfalls. We report a case of secretory carcinoma (SC) of the parotid gland, which was misdiagnosed as acinic cell carcinoma (ACC) on fine-needle aspiration cytology, to describe the cytological features.

Programmed cell death ligand 1 (PD-L1) expression in non-small cell lung cancer: Findings from a tertiary care institute in western part of India.

BACKGROUND: Immune checkpoint inhibitors targeting either programmed cell death protein 1 (PD-1) or programmed cell death ligand 1 (PD-L1) have been established as a novel target for immunotherapy in non-small cell lung cancer (NSCLC). Prevalence of PD-L1 expression in NSCLC varies from 13% to 70%, with sparse data from the Indian subcontinent. In this study, we looked at PD-L1 expression and its association with demographic, clinical, radiologic and pathologic parameters in NSCLC patients. METHODS: This was an observational study carried over a period of 18 months in which 65 patients of NSCLC were included. Immunohistochemistry (IHC) for PD-L1 was done using an automated IHC stainer and testing was performed using PD-L1 IHC CAL10. For statistical analysis, unpaired t test, Chi square test, Fisher's exact test and binomial logistic regression were used. P < 0.05 was taken to be statistically significant. RESULTS: Mean age of the patients was 62.9 ± 9.2 years, and majority (87.3%) of them were males. Seventeen (26.2%) patients expressed PD-L1, among whom 10 had high PD-L1 expression (≥50%) and 7 had low PD-L1 expression (1-49%). PD-L1 expression was seen in 13 out of 43 cases of squamous cell carcinoma (SCC) and 4 out of 15 cases of adenocarcinoma. On applying binomial logistic regression analysis, association between smoking and PD-L1 expression was found to be insignificant. CONCLUSION: Almost a quarter of NSCLC cases were PD-L1 positive without any difference in expression between SCC and adenocarcinoma. PD-L1 status was not associated with any specific demographic, clinical or radiologic parameter including the histologic subtype.

C. difficile intoxicates neurons and pericytes to drive neurogenic inflammation.

Clostridioides difficile infection (CDI) is a major cause of healthcare-associated gastrointestinal infections1,2. The exaggerated colonic inflammation caused by C. difficile toxins such as toxin B (TcdB) damages tissues and promotes C. difficile colonization3-6, but how TcdB causes inflammation is unclear. Here we report that TcdB induces neurogenic inflammation by targeting gut-innervating afferent neurons and pericytes through receptors, including the Frizzled receptors (FZD1, FZD2 and FZD7) in neurons and chondroitin sulfate proteoglycan 4 (CSPG4) in pericytes. TcdB stimulates the secretion of the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) from neurons and pro-inflammatory cytokines from pericytes. Targeted delivery of the TcdB enzymatic domain, through fusion with a detoxified diphtheria toxin, into peptidergic sensory neurons that express exogeneous diphtheria toxin receptor (an approach we term toxogenetics) is sufficient to induce neurogenic inflammation and recapitulates major colonic histopathology associated with CDI. Conversely, mice lacking SP, CGRP or the SP receptor (neurokinin 1 receptor) show reduced pathology in both models of caecal TcdB injection and CDI. Blocking SP or CGRP signalling reduces tissue damage and C. difficile burden in mice infected with a standard C. difficile strain or with hypervirulent strains expressing the TcdB2 variant. Thus, targeting neurogenic inflammation provides a host-oriented therapeutic approach for treating CDI.

Proximal Tibia Primary Leiomyosarcoma: A Case Report and Review of Literature.

The paper at hand presents a unique case of leiomyosarcoma (LMS) involving the left leg in a 56-year-old patient. This individual experienced pain and the presence of a mass for approximately eight months before seeking medical attention. A diagnostic biopsy revealed the presence of multinucleated pleomorphic cells arranged in intersecting fascicles upon immunohistochemistry (IHC) staining for vimentin, caldesmon, and smooth muscle actin. The rarity of LMS in the extremities highlights the need for further understanding and research to determine the most suitable treatment approaches for such patients. In this specific case, the patient underwent tumor excision followed by reconstruction using a megaprosthesis. This report emphasizes the importance of considering unique treatment strategies when dealing with rare neoplasms like LMS in the extremities. As medical knowledge continues to evolve, gaining insights into the optimal management of such cases will be crucial for improving patient outcomes and overall prognosis.

Further explorations into the role of mast cells in deaths associated with fatal asphyxia: an immunohistochemical study utilizing CD 117 marker.

Asphyxia-related deaths have always been a challenging task in the speciality of forensic pathology. Apart from helpful macroscopical signs (e.g., strangulation mark, cyanosis, petechial haemorrhage, and lung oedema), recent literature indicates that prolonged asphyxia is sufficient to induce an increase in mast cells (MC). Inflammatory cells migrate from the bone marrow to the lungs, aiding in the diagnosis of fatal asphyxial deaths. HIF1-α, a key regulator protein, is released from lung tissue capillaries during catastrophic hypoxia circumstances, as previously demonstrated in immunohistochemistry (IHC) research. The present study analyzed lung samples from 164 medico-legal autopsy cases, including 57 asphyxia/hypoxia deaths and 107 controls (non-asphyxial deaths). Peribronchial, perivascular and perialveolar MCs were detected using CD117 antibody, and the average of MCs in each of these locations was noted in each case. The results indicated a statistically significant increase in peribronchial and perialveolar mast cells (MC) in fatal asphyxial deaths, including those caused by hanging, drowning, or postural asphyxia. Peri-bronchial MC in lung sections of asphyxial deaths were in the range of 0.2-5.4 and in non-asphyxial samples were in the range of 0.0-2.2. Peri-alveolar MCs in lung sections of asphyxial deaths were in the range of 0.0-0.6 and in non-asphyxial samples were in the range of 0.0-0.2. Our data suggest that mast cells (MC) play an important role in fatal hypoxia-related mortality and CD 117 may be a reliable marker for detection of mast cells in asphyxial deaths. It could be very beneficial to forensic pathologists tasked with differentiating fatal asphyxia fatalities from other causes of death.

Quantitative estimation of TNF-α and IL-3 by using ELISA from human lung tissue in fatal asphyxial deaths.

Asphyxia-related deaths have always been a challenging task in the specialty of forensic pathology. Apart from helpful macroscopical signs (e.g., strangulation marks, cyanosis, petechial haemorrhage, and lung edema), recent literature indicates that prolonged asphyxia is sufficient to induce an increase in mast cells (MC). Inflammatory cells migrate from the bone marrow to the lungs, aiding in the diagnosis of fatal asphyxial death. The present study analyzed human lung tissue samples from 90 medico-legal autopsy cases, including 45 asphyxial deaths and 45 controls (non-asphyxial deaths). The cases ranged from 2 to 68 years, with a mean age of 33.23 years. In 90 cases, 74 cases were of males, and 16 were of females. Human lung tissue samples were analyzed by using the sandwich ELISA method. The results indicated a statistically significant increase in TNF-α and IL-3 concentration in fatal asphyxial deaths, including those caused by hanging, drowning, and smothering. Mean ± SD in asphyxial and non-asphyxial cases for the TNF-α and IL-3 concentration statistically analysed. In asphyxial cases, the average IL-3 concentration (Conc.) was 1558.50 ± 350.53 pg/ml, and the average TNF-α concentration (Conc.) was 499.75 ± 479.41 pg/ml. In contrast, in non-asphyxial cases, the average IL-3 concentration (Conc.) was found to be 849.73 ± 484.99 pg/ml, and the average TNF-α concentration (Conc.) was 208.08 ± 81.23 pg/ml. The mean change in IL-3 and TNF-α (Conc.) values are found to significant (<0.01) in asphyxial cases as compared to non-asphyxial cases. The ROC (Receiver operating characteristic curve) analysis revealed that TNF-α (AUC = 0.89) and IL-3 (AUC = 0.87) concentration (conc.) were stronger predictors of asphyxial deaths with an optimal cut-off value of 455.20 pg/ml for TNF-alpha and 1700.62 pg/ml for IL-3 respectively. Our findings imply that mast cells (MC) are critical in fatal hypoxia-related mortality and that TNF-α and IL-3 can be reliable markers for detecting mast cells in asphyxial deaths. It could be very beneficial to forensic pathologists tasked with differentiating fatal asphyxial fatalities from other causes of death.