Primary omental infarction - a benign cause of acute abdomen.

Objectives: Omental infarction (OI) is an uncommon cause of acute abdominal pain. A high index of clinical suspicion is required for diagnosis of OI as the incidence is less than 1 %, presenting with abdominal pain. We report primary OI's clinical and radiological profile from a single tertiary care hospital in India. Methods: In this retrospective cross-sectional study, the electronic medical and radiology records of patients with abdominal pain were reviewed over seven years (2015-2022). Variables were systematically collected and analyzed. Results: A total of 22 patients diagnosed with primary OI were included in this study. Male preponderance (63.6 %) was noted with a mean age of 47.45 years (SD ± 13.84; range: 18-72 years). Most patients belonged to class I obesity (according to the Asia-Pacific body mass index classification) with a mean BMI of 26.56 kg/m2 (SD ± 3.21 kg/m2). All patients had abdominal pain as the primary symptom, with a mean duration of 8.64 days (SD ± 10.15; range: 1-42 days). The most common locations of pain were the right hypochondrium (27.3 %) and diffuse (27.3 %), followed by the right iliac fossa (18.1 %). Most (95.45 %, n=21/22) patients were treated conservatively, and only one required surgical intervention. Conclusions: Primary OI is a rare and benign cause of acute abdomen. Obesity is a risk factor but does not correlate with the size or severity of OI. Radiological imaging, like a computed tomography (CT) scan, is essential for diagnosis. A conservative management line should be the first approach in treating primary OI before considering surgical options.

Spontaneous omental infarction as a rare differential for right iliac fossa pain: A case report and review of the literature.

Omental infarction is a rare cause of acute abdominal pain, often benign and self-limiting. The significance of infarction lies in the fact that it can mimic other abdominal pathologies including appendicitis, cholecystitis, pancreatitis, or reflux disease. Diagnostic laparoscopy provides the definitive diagnosis of omental infarction, but it is invasive and limited due to resources. Computed tomography of the abdomen and pelvis has been considered the gold standard to diagnosing omental infarction when a non-invasive diagnostic approach is required. Additionally, ultrasound can also be used alternatively for children. Currently, there is no consensus in the diagnosis and management of patients with imaging-proven omental infarction. Spontaneous infarcted omentum must be considered by surgeons and radiologists as a rare cause of acute abdominal pain as patients can experience good outcomes with either conservative or operative approach. However, conservative management must only be considered in stable patients where alternative pathology is unlikely.

MORPHOLOGICAL DIFFERENCES BETWEEN THE LESSER AND THE GREATER OMENTA IN ALBINO RATS.

BACKGROUND: Publications report that all mammals have two omenta, namely, lesser omentum and greater omentum. Basically, these organs, which share the same name except for the adjective "lesser" or "greater," should not differ from each other. However, no clear description of the structure of the lesser omentum, as well as comparative morphological analysis between the lesser and greater omenta have been found in the literature, which necessitates a thorough investigation. Therefore, the aim of our study was to analyze the morphofunctional differences between the greater and lesser omenta in albino rats. METHOD: The experiment involved 20 mature male albino rats, weighing 298,28±7,36grams. The material for our study were preparations of lesser and greater omenta, fixed in 10% of neutral buffered formalin. Paraffin sections were stained with hematoxylin-eosin and Van Gieson stain. RESULTS: The findings of the study showed that the greater omentum in albino rats, unlike other derivatives of the omentum (ligaments and mesenteries), represents a free extension (mostly from the greater curvature of the stomach), in the form of an "apron," into a specific depth of the peritoneal cavity, duplicating the serous membrane. This duplication is characterized by the composition of two structurally interdependent formations. These include vascular-fatty arcades, associated with lymphoid nodules known as milky spots, and binding serous-reticular membranes. The findings of the study of the lesser omentum have established that in all cases it is located beneath the liver and becomes visualized only after hepatolifting. It is presented in the form of two ligaments: hepatoduodenal and hepatogastric, which contain two main structured formations, which we called vascular-fatty spurs, between these spurs, serous-reticular membranes are located. CONCLUSION: despite having similar names, the lesser omentum, a derivative of the peritoneum, is fundamentally different. As it is well known, the lesser omentum is represented by ligaments that extend from the liver hilus to the lesser curvature of the stomach and the duodenum. Due to this arrangement, the lesser omentum lacks the mobile activity characteristic of the greater omentum, which plays a crucial role in rapid response to damage in the gastrointestinal tract. Despite sharing the same names, both formations differ in shape, morphological structure, development and function.

Adipocyte pyroptosis occurs in omental tumor microenvironment and is associated with chemoresistance of ovarian cancer.

BACKGROUND: Ovarian carcinoma (OC) is a fatal malignancy, with most patients experiencing recurrence and resistance to chemotherapy. In contrast to hematogenous metastasizing tumors, ovarian cancer cells disseminate within the peritoneal cavity, especially the omentum. Previously, we reported omental crown-like structure (CLS) number is associated with poor prognosis of advanced-stage OC. CLS that have pathologic features of a dead or dying adipocyte was surrounded by several macrophages is well known a histologic hallmark for inflammatory adipose tissue. In this study, we attempted to clarify the interaction between metastatic ovarian cancer cells and omental CLS, and to formulate a therapeutic strategy for advanced-stage ovarian cancer. METHODS: A three-cell (including OC cells, adipocytes and macrophages) coculture model was established to mimic the omental tumor microenvironment (TME) of ovarian cancer. Caspase-1 activity, ATP and free fatty acids (FFA) levels were detected by commercial kits. An adipocyte organoid model was established to assess macrophages migration and infiltration. In vitro and in vivo experiments were performed for functional assays and therapeutic effect evaluations. Clinical OC tissue samples were collected for immunochemistry stain and statistics analysis. RESULTS: In three-cell coculture model, OC cells-derived IL-6 and IL-8 could induce the occurrence of pyroptosis in omental adipocytes. The pyroptotic adipocytes release ATP to increase macrophage infiltration, release FFA into TME, uptake by OC cells to increase chemoresistance. From OC tumor samples study, we demonstrated patients with high gasdermin D (GSDMD) expression in omental adipocytes is highly correlated with chemoresistance and poor outcome in advanced-stage OC. In animal model, by pyroptosis inhibitor, DSF, effectively retarded tumor growth and prolonged mice survival. CONCLUSIONS: Omental adipocyte pyroptosis may contribute the chemoresistance in advanced stage OC. Omental adipocytes could release FFA and ATP through the GSDMD-mediate pyroptosis to induce chemoresistance and macrophages infiltration resulting the poor prognosis in advanced-stage OC. Inhibition of adipocyte pyroptosis may be a potential therapeutic modality in advanced-stage OC with omentum metastasis.

Identifying the Morphological and Molecular Features of a Cell-Based Orthotopic Pancreatic Cancer Mouse Model during Growth over Time.

Pancreatic ductal adenocarcinoma (PDAC), characterized by hypovascularity, hypoxia, and desmoplastic stroma is one of the deadliest malignancies in humans, with a 5-year survival rate of only 7%. The anatomical location of the pancreas and lack of symptoms in patients with early onset of disease accounts for late diagnosis. Consequently, 85% of patients present with non-resectable, locally advanced, or advanced metastatic disease at diagnosis and rely on alternative therapies such as chemotherapy, immunotherapy, and others. The response to these therapies highly depends on the stage of disease at the start of therapy. It is, therefore, vital to consider the stages of PDAC models in preclinical studies when testing new therapeutics and treatment modalities. We report a standardized induction of cell-based orthotopic pancreatic cancer models in mice and the identification of vital features of their progression by ultrasound imaging and histological analysis of the level of pancreatic stellate cells, mature fibroblasts, and collagen. The results highlight that early-stage primary tumors are secluded in the pancreas and advance towards infiltrating the omentum at week 5-7 post implantation of the BxPC-3 and Panc-1 models investigated. Late stages show extensive growth, the infiltration of the omentum and/or stomach wall, metastases, augmented fibroblasts, and collagen levels. The findings can serve as suggestions for defining growth parameter-based stages of orthotopic pancreatic cancer models for the preclinical testing of drug efficacy in the future.

Omental torsion mimicking acute appendicitis: A case report.

INTRODUCTION: Omental torsion is a rare cause of acute abdominal pain caused by twisting of the omentum along its long axis, thus compromising its vascularity. Its presentation is non-specific and can mimic other common pathologies, making its pre-operative diagnosis challenging. PRESENTATION OF CASE: A 44-year-old female presented for periumbilical abdominal pain. Her laboratory results showed no leukocytosis and CRP was within normal range. CT scan of the abdomen and pelvis with oral and IV contrast showed a well demarcated pericecal mass at the right side, mostly suggestive of transmesenteric internal herniation with strangulation. The patient eventually required laparoscopic surgical intervention. DISCUSSION: The acute abdominal manifestations in patients with omental torsion are due to the development of edema and necrotic tissue distal of the torsion after the arterial supply and venous drainage have been obstructed. Rotation around the right gastroepiploic artery is considered to be the most common cause of omental torsion. Primary torsion is considered to be idiopathic, while secondary torsion occurs due to an identifiable predisposing pathology such as omental cysts, hernias, adhesions, or intra-abdominal tumors. Since symptoms of omental torsion are non-specific, it is crucial to consider the differential diagnosis and rule out other causes of acute abdomen. Surgical intervention is the mainstay treatment when there is uncertainty in the diagnosis, or when the patient's clinical, radiological, and laboratory findings worsen with conservative treatment. CONCLUSION: Early surgical intervention in cases of omental torsion reduces the incidence of formation of abscesses, adhesions, and omental necrosis. In cases of non-operative candidates, conservative treatment is the best option; therefore, the choice of treatment of omental torsion should be considered on a case-by-case basis.

Laparoscopically treated bowel obstruction secondary to a lesser omental hernia resulting from a previous laparoscopic total colectomy for ulcerative colitis: A report of two cases.

Lesser omental hernias are rare; however, they should be considered in symptomatic bowel obstruction subsequent to a subtotal or total colectomy. This report describes two cases of recurrent bowel obstruction secondary to lesser omental hernias after laparoscopic total colectomies for ulcerative colitis. Initially, these patients had been treated conservatively; however, due to symptom recurrence, surgical intervention was decided on. In both cases, laparoscopic surgery revealed lesser omental hernias. The small bowel, which had entered from the dorsal aspect of the stomach, was returned to the original position, and the lesser omentum was closed. The patients were discharged uneventfully, with no recurrent bowel obstruction during the follow-up period. These cases highlight the importance of including internal hernias in the differential diagnosis relative to recurrent bowel obstruction, in patient subpopulations with a prior history of a subtotal or total colectomy. Confirmation by computed tomography is preferable.

Proteobacteria impair anti-tumor immunity in the omentum by consuming arginine.

Gut microbiota influence anti-tumor immunity, often by producing immune-modulating metabolites. However, microbes consume a variety of metabolites that may also impact host immune responses. We show that tumors grow unchecked in the omenta of microbe-replete mice due to immunosuppressive Tregs. By contrast, omental tumors in germ-free, neomycin-treated mice or mice colonized with altered Schaedler's flora (ASF) are spontaneously eliminated by CD8+ T cells. These mice lack Proteobacteria capable of arginine catabolism, causing increases in serum arginine that activate the mammalian target of the rapamycin (mTOR) pathway in Tregs to reduce their suppressive capacity. Transfer of the Proteobacteria, Escherichia coli (E. coli), but not a mutant unable to catabolize arginine, to ASF mice reduces arginine levels, restores Treg suppression, and prevents tumor clearance. Supplementary arginine similarly decreases Treg suppressive capacity, increases CD8+ T cell effectiveness, and reduces tumor burden. Thus, microbial consumption of arginine alters anti-tumor immunity, offering potential therapeutic strategies for tumors in visceral adipose tissue.

Immunity in adipose tissues: Cutting through the fat.

Well known functions of adipose tissue include energy storage, regulation of thermogenesis, and glucose homeostasis-each of which are associated with the metabolic functions of fat. However, adipose tissues also have important immune functions. In this issue of Immunological Reviews, we present a series of articles that highlight the immune functions of adipose tissue, including the roles of specialized adipose-resident immune cells and fat-associated lymphoid structures. Importantly, immune cell functions in adipose tissues are often linked to the metabolic functions of adipocytes and vice versa. These reciprocal interactions and how they influence both immune and metabolic functions will be discussed in each article. In the first article, Wang et al.,11 discuss adipose-associated macrophages and how obesity and metabolism impact their phenotype and function. Several articles in this issue discuss T cells as either contributors to, or regulators of, inflammatory responses in adipose tissues. Valentine and Nikolajczyk12 provide insights into the role of T cells in obesity-associated inflammation and their contribution to metabolic dysfunction, whereas an article from Kallies and Vasanthakumar13 and another from Elkins and Li14 describe adipose-associated Tregs and how they help prevent inflammation and maintain metabolic homeostasis. Articles from Okabe35 as well as from Daley and Benezech15 discuss the structure and function of fat-associated lymphoid clusters (FALCs) that are prevalent in some adipose tissues and support local immune responses to pathogens, gut-derived microbes and fat-associated antigens. Finally, an article from Meher and McNamara16 describes how innate-like B1 cells in adipose tissues regulate cardiometabolic disease. Importantly, these articles highlight the physical and functional attributes of adipose tissues that are different between mice and humans, the metabolic and immune differences between various adipose depots in the body and the differences in immune cells, adipose tissues and metabolic functions between the sexes. At the end of this preface, we highlight how these differences are critically important for our understanding of anti-tumor immunity to cancers that metastasize to a specific example of visceral adipose tissue, the omentum. Together, these articles identify some unanswered mechanistic questions that will be important to address for a better understanding of immunity in adipose tissues.

A human omentum-specific mesothelial-like stromal population inhibits adipogenesis through IGFBP2 secretion.

Adipose tissue plasticity is orchestrated by molecularly and functionally diverse cells within the stromal vascular fraction (SVF). Although several mouse and human adipose SVF cellular subpopulations have by now been identified, we still lack an understanding of the cellular and functional variability of adipose stem and progenitor cell (ASPC) populations across human fat depots. To address this, we performed single-cell and bulk RNA sequencing (RNA-seq) analyses of >30 SVF/Lin- samples across four human adipose depots, revealing two ubiquitous human ASPC (hASPC) subpopulations with distinct proliferative and adipogenic properties but also depot- and BMI-dependent proportions. Furthermore, we identified an omental-specific, high IGFBP2-expressing stromal population that transitions between mesothelial and mesenchymal cell states and inhibits hASPC adipogenesis through IGFBP2 secretion. Our analyses highlight the molecular and cellular uniqueness of different adipose niches, while our discovery of an anti-adipogenic IGFBP2+ omental-specific population provides a new rationale for the biomedically relevant, limited adipogenic capacity of omental hASPCs.

Mediastinal transposition of the greater omentum for treatment of infected prostheses of the ascending aorta and aortic arch.

OBJECTIVES: The aim of this study was to evaluate the outcomes of transposition of the omentum into the mediastinum to support the replacement of infected aortic grafts or to cover infected aortic grafts that are not amenable for surgical replacement. METHODS: All patients with thoracic aortic graft infections who underwent mediastinal transposition of the omentum at our institution between 2005 and 2023 were included in this study. Mediastinal transposition of the omentum was performed either after replacement of the infected graft ('curative concept') or solely as bailout procedure by wrapping the infected graft ('palliative concept'). The diagnosis, including computed tomography scans during follow-up, was made according to the criteria of the Management of Aortic Graft Infection Collaboration. RESULTS: The patient cohort consisted of 31 patients. Both in-hospital and 1-year mortality were 0% (n = 0) for the curative concept (n = 9) compared to 23% (n = 5) and 41% (n = 9) for the palliative concept (n = 22), respectively. There was no graft infection-associated death or recurrence of infection after 3 years in the curative group. Survival was 52% at 3 years in the palliative group, with freedom of infection in 59% of the patients (n = 13). CONCLUSIONS: Transposition of the omentum and wrapping of the infected aortic prosthetic graft is a useful bailout strategy for patients who are ineligible for replacement of an infected aortic graft. However, mortality stays high. For radical treatment of aortic graft infections, it may prove an effective supportive therapy and represents an important tool in the armamentarium of cardiac surgeons.

Malignant Extrarenal Rhabdoid tumor derived from the greater omentum: A case report and literature review.

BACKGROUND: Malignant extrarenal rhabdoid tumor (MERT) is a rare and highly metastatic tumor, which is more than 75% of patients dying within 6 months of initial diagnosis, and it often leads to misdiagnosis and delayed treatment. CASE: This paper reports a 16-year-old girl who presented with the chief complaint of acute abdominal pain. She underwent laparoscopic exploration and excisional biopsy, then pathological examination and immunohistochemistry revealed "extrarenal malignant rhabdomyoma." One month after operation, she died of intra-abdominal hemorrhage and multiple organ dysfunction. CONCLUSION: MERT were often misdiagnosed and had a poor prognosis. The surgery and chemotherapy are usually beneficial to prolong the survival time of patients with MERT.

Primary omental smooth muscle tumor in an adult male: a diagnostic dilemma for leiomyoma: a case report.

BACKGROUND: The greater omentum comprises peritoneal, adipose, vascular, and lymphoid tissues. Most omental malignancies are metastatic tumors, and the incidence of primary tumors is rare. We report on a prior omental smooth muscle tumor case in an adult male patient. CASE PRESENTATION: A 54-year-old Japanese male patient with no relevant medical history was diagnosed with an abdominal mass during a routine medical checkup. Subsequent contrast-enhanced computed tomography revealed a mass of approximately 3 cm in size in the greater omentum, and a laparotomy was performed. A 27 × 25 × 20 mm raised lesion was found in the omentum. Microscopically, spindle cells were observed and arranged in whorls and fascicles. Individual tumor cells had short spindle-shaped nuclei with slightly increased chromatin and were characterized by a slightly eosinophilic, spindle-shaped cytoplasm. The mitotic count was less than 1 per 50 high-power fields. The tumor cells showed positive immunoreactivity for α smooth muscle actin, HHF35, and desmin on immunohistochemical examination. The Ki-67 labeling index using the average method was 1.76% (261/14806). No immunoreactivity was observed for any of the other tested markers. We considered leiomyoma owing to a lack of malignant findings. However, primary omental leiomyoma has rarely been reported, and it can be difficult to completely rule out the malignant potential of smooth muscle tumors in soft tissues. Our patient was decisively diagnosed with a primary omental smooth muscle tumor considering leiomyoma. Consequently, the patient did not undergo additional adjuvant therapy and was followed up. The patient was satisfied with treatment and showed neither recurrence nor metastasis at the 13-month postoperative follow-up. DISCUSSION AND CONCLUSION: We encountered a primary smooth muscle tumor of the greater omentum with no histological findings suggestive of malignancy in an adult male patient. However, omental smooth muscle tumors are extremely difficult to define as benign, requiring careful diagnosis. Further case reports with long-term follow-up and case series are required to determine whether a true omental benign smooth muscle tumor (leiomyoma) exists. In addition, proper interpretation of the Ki-67 labeling index should be established. This case study is a foundation for future research.

Fat-associated lymphoid clusters: Supporting visceral adipose tissue B cell function in immunity and metabolism.

It is now widely understood that visceral adipose tissue (VAT) is a highly active and dynamic organ, with many functions beyond lipid accumulation and storage. In this review, we discuss the immunological role of this tissue, underpinned by the presence of fat-associated lymphoid clusters (FALCs). FALC's distinctive structure and stromal cell composition support a very different immune cell mix to that found in classical secondary lymphoid organs, which underlies their unique functions of filtration, surveillance, innate-like immune responses, and adaptive immunity within the serous cavities. FALCs are important B cell hubs providing B1 cell-mediated frontline protection against infection and supporting B2 cell-adaptative immune responses. Beyond these beneficial immune responses orchestrated by FALCs, immune cells within VAT play important homeostatic role. Dysregulation of immune cells during obesity and aging leads to chronic pathological "metabolic inflammation", which contributes to the development of cardiometabolic diseases. Here, we examine the emerging and complex functions of B cells in VAT homeostasis and the metabolic complications of obesity, highlighting the potential role that FALCs play and emphasize the areas where further research is needed.

Case report: A rare case of omental extrarenal rhabdoid tumor and review of the literature.

Extrarenal rhabdoid tumor of the greater omentum is extremely rare, with only sporadic reports and limited documentation of its ultrasonographic findings. Here, we report a case of an extrarenal rhabdoid tumor of the greater omentum in a 16-year-old girl and review the relevant literature. It was found that the disease mainly occurred in female children and adolescents, and mainly manifested as lower abdominal pain and a large abdominal cystic or solid hemorrhagic mass. The clinical characteristics include a high degree of malignancy and mortality. Ultrasound shows some malignant features, but it is not specific; thus, it is easy to be misdiagnosed in the clinic.

Development and organization of omental milky spots.

The milky spots in omentum are atypical lymphoid tissues that play a pivotal role in regulating immune responses in the peritoneal cavity. The milky spots act as central hubs for collecting antigens and particles from the peritoneal cavity, regulating lymphocyte trafficking, promoting the differentiation and self-renewal of immune cells, and supporting the local germinal centre response. In addition, the milky spots exhibit unique developmental characteristics that combine the features of secondary and tertiary lymphoid tissues. These structures are innately programmed to form during foetal development; however, they can also be formed postnatally in response to peritoneal irritation such as inflammation, infection, obesity, or tumour metastasis. In this review, I discuss emerging perspectives on homeostatic development and organization of the milky spots.

Morphological Characteristics of the Results of Experimental Modeling of Septic Peritonitis

SUMMARY: Experimental studies devoted to the study of the mechanisms of the pathogenesis of acute peritonitis and the development of new methods of medical and surgical treatment are becoming increasingly relevant. Today, experimental medicine knows many different ways to modeling septic peritonitis and eliminate it, but the role of the local immune system is underestimated, whereas it takes a direct part in inflammation. The objective of our work to study morphological features of results of experimental modeling of septic peritonitis in white rats. The study included 15 sexually mature white male rats weighing 276.75±6.56 grams. A simulation of septic peritonitis was performed by perforating the upper part of the cecum with four punctures with a G16 injection needle. As a result of the experiment, after examination of the peritoneal cavity, all 15 animals were diagnosed with omentum tamponade of perforated damage to the caecum. In 11 cases, the perforated wall of the caecum was covered by the greater omentum (73.34 %), and in the other 4 animals, tamponade was performed by one of the epididymal omentum (26.66 %). The initial stage of tamponade with the greater or epididymal omentums of a perforated caecum begins on the first day of the experiment and consists of tight interstitial consolidation between them, as well as in the invasion of blood vessels from the omentum side to the focus of infection, which ensure the delivery of the appropriate immunocompetent cells. As a result of this process, intensive lymphoid infiltrates are formed in this area, as well as the growth of adipose tissue, which isolates the inflammatory focus from the peritoneal cavity with a thick layer.

Las investigaciones experimentales dedicadas al estudio de los mecanismos de patogénesis de la peritonitis aguda y el desarrollo de nuevos métodos de tratamiento médico y quirúrgico son cada vez más relevantes. Hoy en día, la medicina experimental conoce muchas formas diferentes de modelar la peritonitis séptica y eliminarla, pero se subestima el papel del sistema inmunológico local, mientras que él participa directamente en la inflamación. El objetivo de nuestro trabajo fue estudiar las características morfológicas de los resultados del modelado experimental de peritonitis séptica en ratas blancas. El estudio incluyó 15 ratas macho blancas, sexualmente maduras que pesaban 276,75 ± 6,56 gramos. Se realizó una simulación de peritonitis séptica perforando la parte superior del ciego con cuatro punciones con una aguja de inyección G16. Como resultado del experimento, después del examen de la cavidad peritoneal, a los 15 animales se les diagnosticó taponamiento del omento o lesión perforada del ciego. En 11 casos, la pared perforada del ciego fue recubierta por el omento mayor (73,34 %), y en los otros 4 animales el taponamiento se realizó por uno de los epidídimos (26,66 %). La etapa inicial del taponamiento con omento mayor o epidídimo de un ciego perforado comienza el primer día del experimento y consiste en una estrecha consolidación intersticial entre ellos, así como en la invasión de los vasos sanguíneos desde el lado del omento hasta el foco de infección, que aseguran la entrega de las células inmunocompetentes apropiadas. Como resultado de este proceso, se forman intensos infiltrados linfoides en esta zona, así como el crecimiento de tejido adiposo, que aísla el foco inflamatorio de la cavidad peritoneal con una gruesa capa.

Subtotal cholecystectomy with omental pedicle plug for the challenging gallbladder: A case report and review of the literature.

If patient anatomy or disease does not allow for a traditional or partial cholecystectomy, an omental pedicle plug may be a viable option to limit the risk of postoperative uncontrolled bile leak from the cystic duct and to control patient symptoms.

Patient-Derived Exosomes as siRNA Carriers in Ovarian Cancer Treatment.

RNA interference is a powerful gene-silencing tool with potential clinical applications. However, its therapeutic use is challenging because suitable carriers are unavailable. Exosomes are stable small endogenous vesicles that can transport functional molecules to target cells, making them ideal small interfering RNA (siRNA) carriers. Herein, we elucidated the therapeutic potential of patient-derived exosomes as an siRNA carrier for ovarian cancer (OC) treatment. The exosomes were extracted from the culture medium of primary fibroblasts collected from the omentum of patients with OC during surgery. MET proto-oncogene, receptor tyrosine kinase (MET) was selected for gene silencing, c-Met siRNAs were synthesized and loaded into the exosomes (Met-siExosomes) via electroporation, and the treatment effect of the Met-siExosomes was assessed in vitro and in vivo. The Met-siExosomes downregulated the c-Met protein levels and inhibited OC cell proliferation, migration, and invasion. In xenograft experiments using SKOV3-13 and ES-2 cells, Met-siExosomes were selectively extracted from peritoneally disseminated tumors. Intraperitoneal treatment suppressed the c-Met downstream targets in cancer cells and prolonged mouse survival. The synthesized siRNAs were successfully and selectively delivered via the exosomes to intraperitoneally disseminated tumors. As patients with OC routinely undergo omentectomy and abundant fibroblasts can be easily collected from the omentum, patient-derived exosomes may represent a promising therapeutic siRNA carrier to treat OC.

Hiatal Hernia of Stomach and Lesser Omentum in a Cadaver: Is It a Type III or IV?

Hiatal hernias, protrusions of abdominal viscera through the esophageal hiatus, are classified into four types. Types I and II involve ascent of the stomach without affecting the gastroesophageal junction. Types III and IV involve the gastroesophageal junction. Type IV specifically may have stomach as well as other abdominal organ involvement, such as pancreas or omentum. Among these types, type IV is the most complex and rare form, accounting for only 0.1% of all cases of hiatal hernias. This report presents a case of a type IV hiatal hernia involving the lesser omentum and a significant portion of the stomach in an 86-year-old male cadaver with a history of mediastinal surgery. To our knowledge, this presentation in a cadaver has not previously been reported in the literature.  This case highlights classification inconsistencies in the literature, particularly regarding type IV hiatal hernias. It is unclear given the current classification system, whether this presentation would be considered a type III or type IV hiatal hernia as it fits both criteria and there are several interpretations of the criteria of a type IV hiatal hernia. Inconsistencies in the classification system may impede standardization of care. This report highlights the need for a more precise classification system that better accounts for anatomical changes and clinical presentation.