Expression of Atoh1, Gfi1, and Pou4f3 in the mature cochlea reprograms nonsensory cells into hair cells.

Mechanosensory hair cells of the mature mammalian organ of Corti do not regenerate; consequently, loss of hair cells leads to permanent hearing loss. Although nonmammalian vertebrates can regenerate hair cells from neighboring supporting cells, many humans with severe hearing loss lack both hair cells and supporting cells, with the organ of Corti being replaced by a flat epithelium of nonsensory cells. To determine whether the mature cochlea can produce hair cells in vivo, we reprogrammed nonsensory cells adjacent to the organ of Corti with three hair cell transcription factors: Gfi1, Atoh1, and Pou4f3. We generated numerous hair cell-like cells in nonsensory regions of the cochlea and new hair cells continued to be added over a period of 9 wk. Significantly, cells adjacent to reprogrammed hair cells expressed markers of supporting cells, suggesting that transcription factor reprogramming of nonsensory cochlear cells in adult animals can generate mosaics of sensory cells like those seen in the organ of Corti. Generating such sensory mosaics by reprogramming may represent a potential strategy for hearing restoration in humans.

Cellular reprogramming with ATOH1, GFI1, and POU4F3 implicate epigenetic changes and cell-cell signaling as obstacles to hair cell regeneration in mature mammals.

Reprogramming of the cochlea with hair-cell-specific transcription factors such as ATOH1 has been proposed as a potential therapeutic strategy for hearing loss. ATOH1 expression in the developing cochlea can efficiently induce hair cell regeneration but the efficiency of hair cell reprogramming declines rapidly as the cochlea matures. We developed Cre-inducible mice to compare hair cell reprogramming with ATOH1 alone or in combination with two other hair cell transcription factors, GFI1 and POU4F3. In newborn mice, all transcription factor combinations tested produced large numbers of cells with the morphology of hair cells and rudimentary mechanotransduction properties. However, 1 week later, only a combination of ATOH1, GFI1 and POU4F3 could reprogram non-sensory cells of the cochlea to a hair cell fate, and these new cells were less mature than cells generated by reprogramming 1 week earlier. We used scRNA-seq and combined scRNA-seq and ATAC-seq to suggest at least two impediments to hair cell reprogramming in older animals. First, hair cell gene loci become less epigenetically accessible in non-sensory cells of the cochlea with increasing age. Second, signaling from hair cells to supporting cells, including Notch signaling, can prevent reprogramming of many supporting cells to hair cells, even with three hair cell transcription factors. Our results shed light on the molecular barriers that must be overcome to promote hair cell regeneration in the adult cochlea.

Randomized clinical trial: Combination antiretroviral therapy with tenofovir-emtricitabine and lopinavir-ritonavir in patients with primary biliary cholangitis.

BACKGROUND: Prior studies using reverse transcriptase inhibitors to treat a human betaretrovirus (HBRV) in patients with primary biliary cholangitis (PBC) resulted in a 21% reduction in alkaline phosphatase (ALP). Herein, we studied the safety and efficacy of combination tenofovir-emtricitabine (TDF/FTC) and lopinavir-ritonavir (LPRr) in PBC patients unresponsive to ursodeoxycholic acid (UDCA). METHODS: A double-blind randomized controlled trial was performed in patients on UDCA for 6 months or more with ALP levels greater than two-fold the upper limit of normal or bilirubin greater than the upper limit of normal. Patients were randomized to daily TDF/FTC 300/200 mg and LPRr 800/200 mg versus identical placebo for 6 months. The primary endpoint was reduction of ALP below 1.67 × ULN or normalization of bilirubin. HBRV DNA levels were assessed in peripheral blood mononuclear cells (PBMC) using digital droplet polymerase chain reaction. RESULTS: The enrolment was limited to 13 patients because most patients were unable to tolerate LPRr due to the development of gastrointestinal symptoms. No difference in the primary endpoint was achieved. A significant reduction was observed in ALP by 25% (P < 0.05) and in HBRV proviral load (P < 0.05) after 6 months of combination antiretroviral therapy. The majority of patients had diminished levels of LPRr after 6 months' therapy suggesting inadequate intake of protease inhibitor toward the end of the study. CONCLUSIONS: Combination anti-retroviral therapy resulted in improvement in hepatic biochemistry with reduction in proviral load. The frequency of side effects from LPRr in patients with PBC exceeds the frequency reported for HIV, warranting the search for better tolerated combinations in future studies.

Perforated Gastrointestinal Stromal Tumor of the Meckel's Diverticulum: a Case Report and Review of Literature.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the GI tract, they have a wide spectrum of clinical manifestations, and a small proportion of them present as an acute abdomen due to obstruction, perforation, or hemoperitoneum. We present a case of a perforated GIST of the Meckel's diverticulum and review the current literature on perforated GISTs. We ran a search on Pubmed and Google Scholar with the following terms "perforated GIST," "perforated Meckel's diverticulum," "GIST with peritonitis," and "GIST in Meckel's diverticulum." After selecting the relevant articles, we tabulated our results and analyzed the data. Out of the 45 cases, 32 (71.1 %) were male and 13 (28.8 %) were female. Out of the 45 reported cases, 41 (91.1 %) were from the small intestine, 2 (4.44 %) cases from the stomach, and 2 (4.44 %) from the small bowel. In 15 (33.33 %) cases, the site of perforation was the Meckel's diverticulum (MD). Forty-year-old male, presented with features of peritonitis localized to the right iliac fossa, was diagnosed as acute appendicitis and subjected to a diagnostic laparoscopy. Intraoperatively, a perforated Meckel's diverticulum was found, which on histopathological examination contained a low-grade GIST. Our literature search revealed that in reported cases of perforated GISTs, there is a slight male preponderance. Small bowel appears to be the most common site for a perforated GIST, and a significant proportion (30.23 %) arise from the Meckel's diverticulum. And most importantly, the commonest tumor to cause perforation of a Meckel's diverticulum is a GIST.

Breast Lumps That Do Not Arise from the Breast.

An elderly lady presented to the surgical outpatient with a lump in her breast. On examination, there was a well-defined large lump measuring about 12 × 10 cm, hard in consistency and fixed to the chest wall, the skin appeared to be free, and the nipple-areola complex was normal. A provisional diagnosis of phylloides tumor was made, but digital rectal examination revealed a circumferential rectal growth. To our surprise, biopsy of the rectal growth and the chest wall mass revealed similar adenocarcinoma cells. This image illustrates the possibility that a common clinical entity such as a breast lump can sometimes surprise even the most seasoned clinicians.

Mass in the Left Iliac Fossa-a Diagnostic Dilemma.

Clinical diagnosis of abdominal masses remains a challenge to this day; in spite of the availability of advanced imaging facilities, we fail to reach a definitive diagnosis in a few cases and have to resort to a laparotomy, which reveals unexpected findings. We present a case of a 70-year-old lady who presented with pain abdomen and loss of appetite for 3 months; clinical examination revealed a fixed intra-abdominal firm to hard mass in the left iliac fossa. CT scan of the abdomen showed a large cystic hypodense lesion in the left iliac, lumbar and hypogastric region with no definite organ of origin. The patient underwent an exploratory laparotomy and in toto excision of the cyst; on opening the cyst wall, we found multiple daughter cysts in a pool of thick, purulent fluid. Microscopic examination confirmed the presence of a hydatid cyst Primary peritoneal hydatid cysts are a rare entity and constitute around 2 % of hydatid cysts found in the human body. Very few cases of primary peritoneal hydatid cyst have been reported from non-endemic areas, and this case report highlights the need to maintain a high index of suspicion while evaluating cystic abdominal swellings.

Synchronous malignancies of the gall bladder and common bile duct: a case report.

BACKGROUND: Synchronous malignancies of the gall bladder and common bile duct are a rare entity. Much of our knowledge on this topic comes from Japanese literature. Most of the synchronous carcinomas described in Japanese literature are associated with the presence of an anomalous pancreatic-bile duct junction (APBDJ). CASE PRESENTATION: We report a case of synchronous malignancy of the extrahepatic biliary tree involving the fundus of the gall bladder and the intrapancreatic portion of the common bile duct (CBD). A 50-year-old female patient presented to us with clinical features of obstructive jaundice and on radiological evaluation was diagnosed to have a periampullary carcinoma; the patient underwent a pancreaticoduodenectomy, and histopathological examination revealed adenocarcinoma of the gall bladder and the intrapancreatic portion of the CBD. CONCLUSIONS: Synchronous malignancies have been rarely reported from the Indian subcontinent; therefore, it is essential for the clinician as well as the pathologist to maintain a high index of suspicion while evaluating such lesions and to look for the presence of an anamolous pancreatic-bile duct junction whenever indicated.