Histological and structural effects of biodegradable polydioxanone stents in the rabbit trachea.

OBJECTIVES: The aim of this study was to evaluate the potential biologic effects caused by the successive placement of biodegradable polydioxanone (PDO) stents in the rabbit trachea. PDO stents could eventually induce a fibroproliferative reaction in the submucosa that could be beneficial in the treatment of malacia due to an increase in its consistency without impairing the tracheal lumen. METHODS: Sixteen adult NZ rabbits were distributed into 3 groups with different survival times according to the number of stents placed: 1 stent (14 weeks), 2 stents (28 weeks) and 3 stents (42 weeks). Stent insertion was performed endoscopically in the cervical trachea of the animal. Histopathological studies included Masson's trichrome staining for submucosal fibrosis and Safranin O to assess the structural integrity of cartilage. Potential inflammatory changes were analysed by means of immunohistochemistry determining the number of CD45-positive cells. RESULTS: Stent placement was successful in every case. Histological studies did not show a statistically significant increase in tracheal wall collagen area and cartilage structure was not modified in those rabbits with 1 or more PDO stents inserted compared to non-stented tracheal sections. Furthermore, no statistically significant changes in the number of CD45+ cells were observed in stented tracheal segments compared to normal tracheal tissues. CONCLUSIONS: According to our data, successive PDO stenting caused mild inflammatory changes in the tracheal wall and no increase in the collagen matrix, and the cartilaginous support was not modified during a long follow-up period (up to 42 weeks). These findings suggest that they may be safe and show good biocompatibility in the long term.

Severe Acute Kidney Injury Due to Intraglomerular Melanoma: A Case Report.

Metastatic disease in the kidney is relatively uncommon compared to other body sites. In most cases it presents as a unilateral and unifocal mass in the tubulointerstitial region. Intraglomerular metastases are even rarer, and their diagnosis is hampered by the limitations of imaging techniques in detecting them. We describe the finding of intraglomerular metastases in a patient affected by a malignant melanoma considered to be in partial remission, with no evidence of melanoma progression on the previously performed computed tomography scan. This patient developed rapidly progressive kidney failure, proteinuria, and hematuria with dysmorphic red blood cells in the urine sediment. Kidney biopsy showed a marked crescentic proliferation caused by tumor cells, which even invaded the proximal convoluted tubule. Melanoma cells were also found in the lumina of the glomerular capillaries, distending their basement membranes. Our case describes the histologic and electron microscopic findings of this form of intraglomerular metastasis and reminds us of its inclusion in the differential diagnosis of rapidly progressive kidney failure.

Mesoamerican nephropathy: A not so unknown chronic kidney disease. / Nefropatía endémica mesoamericana: una enfermedad renal crónica de origen no tan desconocido.

From 2000, Mesoamerican region has reached an important rate of chronic kidney disease of unknown etiology. Under the name of Meroamerican Nephropathy (MeN) several hypotheses (including dehydration, heat stress, environmental or toxic exposure or even infections) have tried to explain the etiology this new disease. MeN affects young men, agricultural workers exposed to high temperatures. MeN courses with unspecific symptoms as low-grade fever and dysuria and progressive kidney disease with impaired renal function and hydroelectrolyte disturbances. The diagnosis requires kidney biopsy showing tubule-interstitial nephritis (usually at chronic stage). Although MeN conditions a high morbi-mortality in endemic regions, there is a lack of specific treatment and only preventive measures have demonstrated some effect of prognosis (avoid heat stress, constant hydration). In this review we aim to summarize the available information of MeN, illustrating the information in a case report.

Tumor-Stromal Interactions in a Co-Culture Model of Human Pancreatic Adenocarcinoma Cells and Fibroblasts and Their Connection with Tumor Spread.

One key feature of pancreatic ductal adenocarcinoma (PDAC) is a dense desmoplastic reaction that has been recognized as playing important roles in metastasis and therapeutic resistance. We aim to study tumor-stromal interactions in an in vitro coculture model between human PDAC cells (Capan-1 or PL-45) and fibroblasts (LC5). Confocal immunofluorescence, Enzyme-Linked Immunosorbent Assay (ELISA), and Western blotting were used to evaluate the expressions of activation markers; cytokines arrays were performed to identify secretome profiles associated with migratory and invasive properties of tumor cells; extracellular vesicle production was examined by ELISA and transmission electron microscopy. Coculture conditions increased FGF-7 secretion and α-SMA expression, characterized by fibroblast activation and decreased epithelial marker E-cadherin in tumor cells. Interestingly, tumor cells and fibroblasts migrate together, with tumor cells in forming a center surrounded by fibroblasts, maximizing the contact between cells. We show a different mechanism for tumor spread through a cooperative migration between tumor cells and activated fibroblasts. Furthermore, IL-6 levels change significantly in coculture conditions, and this could affect the invasive and migratory capacities of cells. Targeting the interaction between tumor cells and the tumor microenvironment might represent a novel therapeutic approach to advanced PDAC.

Mesoamerican nephropathy: A not so unknown chronic kidney disease.

From 2000, Mesoamerican region has reached an important rate of chronic kidney disease of unknown etiology. Under the name of Meroamerican Nephropathy (MeN) several hypotheses (including dehydration, heat stress, environmental or toxic exposure or even infections) have tried to explain the etiology this new disease. MeN affects young men, agricultural workers exposed to high temperatures. MeN courses with unspecific symptoms as low-grade fever and dysuria and progressive kidney disease with impaired renal function and hydroelectrolyte disturbances. The diagnosis requires kidney biopsy showing tubule-interstitial nephritis (usually at chronic stage). Although MeN conditions a high morbi-mortality in endemic regions, there is a lack of specific treatment and only preventive measures have demonstrated some effect of prognosis (avoid heat stress, constant hydration). In this review we aim to summarize the available information of MeN, illustrating the information in a case report.

Histiocytic hyperplasia with hemophagocytosis and acute alveolar damage in COVID-19 infection.

The spectrum of COVID-19 infection includes acute respiratory distress syndrome (ARDS) and macrophage activation syndrome (MAS), although the histological basis for these disorders has not been thoroughly explored. Post-mortem pulmonary and bone marrow biopsies were performed in 33 patients. Samples were studied with a combination of morphological and immunohistochemical techniques. Bone marrow studies were also performed in three living patients. Bone marrow post-mortem studies showed striking lesions of histiocytic hyperplasia with hemophagocytosis (HHH) in most (16/17) cases. This was also observed in three alive patients, where it mimicked the changes observed in hemophagocytic histiocytosis. Pulmonary changes included a combination of diffuse alveolar damage with fibrinous microthrombi predominantly involving small vessels, in particular the alveolar capillary. These findings were associated with the analytical and clinical symptoms, which helps us understand the respiratory insufficiency and reveal the histological substrate for the macrophage activation syndrome-like exhibited by these patients. Our results confirm that COVID-19 infection triggers a systemic immune-inflammatory disease and allow specific therapies to be proposed.

Switching from endoscopic submucosal dissection to salvage piecemeal knife-assisted snare resection to remove a lesion: A preoperative risk score from the beginning.

BACKGROUND AND AIMS: endoscopic submucosal dissection (ESD) in the Western setting remains a challenge. Therefore, other simplified techniques such as knife-assisted snare resection (KAR) have been reported to overcome this issue. METHODS: patients who underwent an ESD for the treatment of gastrointestinal neoplasms were included in a retrospective cross-sectional observational study. Factors associated with the end of ESD as a salvage p-KAR were identified and a logistic regression model was developed. RESULTS: a total of 136 lesions in 133 patients were analyzed. Operator experience of under 50 cases and the combination of lesion size > 30 mm and colorectal location were independent predictive factors for switching to a salvage p-KAR according to the multivariate logistic regression analysis. We developed a risk scoring system based on these four variables (experience, size, location and the combination of size and location) with a receiver operating characteristic curve of 0.81 (95% CI: 0.74-0.89). The diagnostic accuracy of the score for a cut-off point ≥ 5 had a sensitivity of 0.79 (95% CI: 0.66-0.93) and a specificity of 0.71 (95% CI: 0.61-0.80). CONCLUSION: a simple predictive score system that includes four preoperative factors accurately predicts ESD to finish as a p-KAR. A careful selection of cases considering these variables could be useful to achieve better outcomes in the Western setting.

Overexpression of PIK3CA in head and neck squamous cell carcinoma is associated with poor outcome and activation of the YAP pathway.

OBJECTIVES: Phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) is commonly altered in many human tumors, leading to the activation of p110α enzymatic activity that stimulates growth factor-independent cell growth. PIK3CA alterations such as mutation, gene amplification and overexpression are common in head and neck squamous cell carcinoma (HNSCC) and. We aim to explore how these alterations and clinical outcome are associated, as well as the molecular mechanisms involved. MATERIAL AND METHODS: Mutation and copy-number variation in PIK3CA, and whole-genome expression profiles, were analyzed in primary HNSCC tumors from The Cancer Genome Atlas (TCGA) cohort (n = 243). The results were validated in an independent cohort form the University Hospital of A Coruña (UHAC, n = 62). Expression of the PIK3CA gene protein product (PI3K p110α) and nuclear YAP were assessed in tissue microarrays in a cohort from the University Hospital 12 de Octubre (UH12O, n = 91). RESULTS: Only high expression of the PIK3CA gene was associated with poor clinical outcome. The study of gene expression, transcription factor and protein signatures suggested that the activation of the Hippo-YAP pathway, involved in organ size, stem cell maintenance and tumorigenesis, could underlie tumor progression in PI3KCA overexpressing tumors. Tissue arrays showed that PI3K p110α levels correlated with YAP nuclear localization in HNSCC tumors. CONCLUSIONS: High expression of PIK3CA in HNSCC primary tumors identifies patients at high risk for recurrence. In these tumors, progression could rely on the Hippo-YAP pathway instead of the canonical Akt/mTOR pathway. This observation could have important implications in the therapeutic options for patients.

Papular Clear Cell Hyperplasia of the Eccrine Duct: A Precursor Lesion of Clear Cell Syringoma?

We report the case of a 77-year-old diabetic patient with asymptomatic papular eruption developed over a cutaneous scar after the resection of a squamous cell carcinoma. Histological examination revealed a clear cell proliferation involving the secretory portion of the eccrine glands. This entity has been previously named as papular clear cell hyperplasia of the eccrine duct. This clear cell change might be caused by glycogen deposition because of diabetes. We postulate that papular clear cell hyperplasia could be a precursor lesion of clear cell syringoma.

Endoscopic submucosal dissection (ESD) of antral subepithelial lesion suspected of malignancy.

Subepithelial gastric tumours comprise a heterogeneous group of lesions. Endoscopic ultrasonography with fine-needle aspiration (EUS-FNA) is a useful approach but cannot always offer a definitive diagnosis to guide future therapeutic decisions. In the case we describe, biopsy samples of an antral subepithelial lesion and cytological analysis obtained with an EUS-FNA suggested the diagnosis of an adenocarcinoma. Endoscopic submucosal dissection (ESD) allowed en bloc resection of the tumour ensuring diagnosis and providing a definitive treatment.