Microbiota alert: Proteobacteria consume arginine to dampen omental antitumor immunity.

The microbiota can impact antitumor immunity, but whether the microbiota regulates omental antitumor immunity remains elusive. In this issue of Cell Host & Microbe, Meza-Perez et al. demonstrated that Proteobacteria consume arginine to increase Treg cell suppressive capacity and inhibit antitumor immune responses, promoting tumor growth in the omentum.

Torta omental? / Omental cake?

La torta omental describe la presencia de material infiltrativo en la grasa epiploica. El carcinoma de ovario es el proceso maligno clásicamente relacionado con las tortas omentales; sin embargo, las neoplasias malignas que pueden desarrollarlo son múltiples. Igualmente, procesos agudos o crónicos de índole inflamatoria e infecciosa pueden llevar a esta situación. De hecho, si bien la presencia de torta omental siempre implica descartar malignidad, en la edad pediátrica son más frecuentes estas otras etiologías. La clínica de la infiltración epiploica suele ser muy inespecífica, independientemente de la etiología. Los casos descritos suelen debutar con dolor abdominal mal localizado de días o semanas de evolución. La torta omental, en esencia, es un signo radiológico; por tanto, su diagnóstico implica la realización de una o varias pruebas de imagen. El gold standard es la tomografía computarizada (TC). La ecografía es una buena alternativa en niños. Si la causa de la torta omental es incierta, es necesario el examen anatomopatológico de una muestra de tejido peritoneal. Finalmente, el tratamiento en casos de omental cake depende de la etiología. En general, la presencia de este signo radiológico en el seno de una enfermedad neoplásica implica peores resultados. En cambio, en procesos infecciosos es posible un tratamiento dirigido con erradicación del patógeno implicado, consiguiendo una evolución clínica favorable (AU)

Omental cake describes the presence of infiltrative material in the epiploic fat. Ovarian carcinoma is the malignant process classically associated with omental cakes; however, there are multiple malignant neoplasms that can lead to its development. Similarly, acute or chronic inflammatory and infectious processes can lead to this condition. In fact, while the presence of omental cake always implies the need to rule out malignancy, these other etiologies are more common in the pediatric age group. The clinical presentation of epiploic infiltration is usually nonspecific, regardless of the etiology. Described cases often present with poorly localized abdominal pain that has been present for days or weeks. Omental cake, essentially, is a radiological sign; therefore, its diagnosis involves performing one or more imaging tests. The gold standard is computed tomography (CT). Ultrasound is a good alternative to CT as an initial test, especially in children, where neoplastic causes of omental cake are rare. If the cause of omental cake is uncertain, a histopathological examination of a peritoneal tissue sample is necessary. Finally, the treatment for omental cake depends on the etiology. In general, the presence of this radiological sign within a neoplastic disease implies worse outcomes. Conversely, in infectious processes, targeted treatment aiming to eradicate the implicated pathogen can lead to a favorable clinical course. (AU)

Stromal Cells Covering Omental Fat-Associated Lymphoid Clusters Trigger Formation of Neutrophil Aggregates to Capture Peritoneal Contaminants.

The omentum is a visceral adipose tissue rich in fat-associated lymphoid clusters (FALCs) that collects peritoneal contaminants and provides a first layer of immunological defense within the abdomen. Here, we investigated the mechanisms that mediate the capture of peritoneal contaminants during peritonitis. Single-cell RNA sequencing and spatial analysis of omental stromal cells revealed that the surface of FALCs were covered by CXCL1+ mesothelial cells, which we termed FALC cover cells. Blockade of CXCL1 inhibited the recruitment and aggregation of neutrophils at FALCs during zymosan-induced peritonitis. Inhibition of protein arginine deiminase 4, an enzyme important for the release of neutrophil extracellular traps, abolished neutrophil aggregation and the capture of peritoneal contaminants by omental FALCs. Analysis of omental samples from patients with acute appendicitis confirmed neutrophil recruitment and bacterial capture at FALCs. Thus, specialized omental mesothelial cells coordinate the recruitment and aggregation of neutrophils to capture peritoneal contaminants.

Antibacterial spectrum of human omentum and differential expression of beta defensins.

BACKGROUND: Human ß defensins (hBD1 and hBD2) are cationic, cysteine-rich peptides and form an integral part of the mammalian innate immune system. hBD1 is constitutively expressed in epithelial cells, whereas hBD2 increases in response to bacterial infection. Human omentum is known for its anti-inflammatory properties and also possesses an antibacterial activity of its own. We hypothesized that antimicrobial peptides, ß defensins, may govern host defense mechanism in the microbe-rich environment of the peritoneal cavity. Therefore, we analyzed the expression of hBD1 and hBD2 in omentum tissue in vivo and also studied the antibacterial activity of omentum against common pathogens. METHODOLOGY: Omentum tissues were obtained from 30 patients (15 cases and 15 controls). Real-time polymerase chain reaction (PCR) was used to evaluate the mRNA expression of hBD1 and hBD2. Protein quantification was done using Western blotting technique. Antibacterial susceptibility was performed to check the antibacterial activity of omentum. RESULT: Significantly higher expression of hBD2 was observed in cases compared to controls at both the transcriptional and translational levels. In comparison with an array of antibiotics, activated omentum also showed antibacterial property even at lower concentration of its extract. CONCLUSION: Omentum directly responds to bacterial infection, which may be due to differential expression of hBD1 and hBD2 in human omental tissue. These peptides (hBD1 and hBD2) may be an ideal candidate for novel antibiotic class with a broad-spectrum activity.

Actinomycosis of the omentum with invasion of the abdominal wall, small bowel and transverse colon mimicking malignancy.

We report the case of a 59-year-old Russian man who presented with a painless, slow-growing, epigastric mass. CT revealed a large heterogeneous mass within the omentum infiltrating into adjacent tissues. During diagnostic laparoscopy, the omental mass was noted to be firm, raising the suspicion of malignancy. Surgical en-bloc resection of the mass, including the posterior rectus sheath, transverse colon and small bowel, was performed with primary anastomoses at laparotomy. Histological examination was inconsistent with malignancy and revealed the mass to be actinomycosis, confirmed by microscopy and gram staining. Surgical resection was followed by an 8-week course of penicillin and doxycycline antibiotic therapy. This treatment resulted in full clinical and radiological recovery with no complications. Although the clinical and radiological findings, in this case, were highly suspicious of malignancy, abdominal actinomycosis should be considered a differential diagnosis in patients with infiltrative abdominal masses and mild constitutional symptoms.

Screening for genital tuberculosis in a limited resource country: case report.

BACKGROUND: Screening for benign or malignant process of pelvis in young females is a challenge for a physician in a limited resource country. Tuberculosis should be always considered in the differential diagnosis of a pelvic mass in countries with high prevalence of tuberculosis. Negative results of analysis of peritoneal fluid for acid-fast staining, late cultures, and unavailability of new diagnostics methods such as polymerase chain reaction and adenosine deaminase of the aspirated fluid from peritoneal cavity can often result in invasive diagnostic procedures such as laparotomy. CASE PRESENTATION: We report a case of a 24 year old Albanian unemployed female living in urban place in Kosovo who presented with abdominal pain, loss of appetite, fever, headache, a weight loss, nonproductive cough and menstrual irregularity for three weeks. In this example case, the patient with cystic mass in tubo-ovarial complex and elevated serum cancer antigen 125 levels was diagnosed for genital tuberculosis after performing laparotomy. Caseose mass found in left tubo-ovarial complex and histopathological examination of biopsied tissue were the fastest diagnostic tools for confirming pelvis TB. The Lowenstein-Jensen cultures were positive after six weeks and her family history was positive for tuberculosis. CONCLUSION: Young females with abdominopelvic mass, ascites, a positive family history for tuberculosis and high serum cancer antigen 125, should always raise suspicion of tuberculosis especially in a limited resource country. A laparoscopy combined with peritoneal biopsy should be performed to confirm the diagnosis as this could lead to a prevention of unnecessary laparotomies.

Tissue Xpert™ MTB/Rif assay is of limited use in diagnosing peritoneal tuberculosis in patients with exudative ascites.

BACKGROUND: Xpert™ MTB/Rif is a multiplex hemi-nested real-time PCR-based assay to detect presence of M. tuberculosis within 2 hours of sample collection. The present study aimed at assessing efficacy of Xpert™ MTB/Rif assay for diagnosing peritoneal tuberculosis. METHODS: Patients with exudative ascites, fluid negative for acid-fast bacilli on auramine O fluorescence staining and unyielding fluid cytology for malignant cells, were included. Ultrasound-guided omental biopsy samples were obtained in all. Xpert™ MTB/Rif assay on tissue samples was assessed against a composite "reference" standard for diagnosis of peritoneal tuberculosis, defined as presence of any of the three-culture showing M tuberculosis, granulomatous inflammation on histology or resolution of ascites with 2 months of antitubercular therapy. RESULTS: During January 2012-July 2013, 28 patients (age:43 ± 15 years; mean ± SD; male:20) were recruited. Serum ascitic albumin gradient was <1.1 in all except in four patients with underlying cirrhosis. Twenty-one of the 28 patients had peritoneal TB as diagnosed by composite reference standard (histology:18; culture:4; treatment response:3). Seven patients (25%) had an alternative diagnosis (metastatic carcinoma 2, adenocarcinoma 2, mesothelioma 2, and systemic lupus erythematous 1). Xpert™ MTB/Rif assay was positive in 4/21 patients with peritoneal tuberculosis and in none of the 7 patients with alternative diagnosis. Thus, sensitivity, specificity, positive, and negative predictive values for tissue Xpert™ MTB/Rif assay in diagnosing peritoneal tuberculosis were 19% (95% C.I: 6% to 42%), 100% (95% C.I: 59% to 100%), 100% (40% to 100%), and 29% (95% C.I: 13% to 51%), respectively. INTERPRETATION AND CONCLUSION: Tissue Xpert™ MTB/Rif assay was of limited use in diagnosing peritoneal tuberculosis.

[Life-threatening appendicitis caused by Fusobacterium necrophorum].

Fusobacterium necrophorum is a well-known cause of Lemierre's syndrome. Recent studies suggest a causative association between F. necrophorum and acute appendicitis. We present a case of a 15-year-old previously healthy girl who presented with acute non-perforated appendicitis, intra-abdominal abscesses and thrombosis that led to omental necrosis. This resulted in a life-threatening septic shock with the need for prolonged intensive care. We suggest that F. necrophorum identified in pus from the abdomen caused this fulminant variation of appendicitis with findings similar to those seen with Lemierre's syndrome.

[Primary omental actinomycosis]. / Primær aktinomykose i omentum majus.

We report a case of omental actinomycosis in a female patient with an intrauterine device. A computed tomography had shown an inflammatory tumour in the abdomen. The patient was treated with laparoscopic resection of the tumour and prolonged antibiotic therapy. Abdominal actinomycosis should be considered as a differential diagnosis in patients with abdominal symptoms and unspecific clinical, radiological and laboratory findings. Definitive diagnosis of actinomycosis requires histological examination of affected tissue. Laparoscopic resection seems feasible as an alternative to open surgery.

A 33-year-old Haitian immigrant with 7 months of abdominal pain and progressive distension.

We report a case of a 33-year-old previously healthy Haitian immigrant with a 7-month history of abdominal pain, fever and ascites. He had a history of positive tuberculin skin test but never underwent treatment for latent tuberculosis (TB) infection. Initial examination showed abdominal distension. Abdominal CT scan showed mild ascites, abnormal soft tissue in the greater omentum and small bowel mesentery, retroperitoneal adenopathy, peritoneal thickening and dilated loops of small bowel. Paracentesis and thoracentesis were initially non-diagnostic. HIV testing was negative. The differential diagnosis included lymphoma and TB peritonitis. The omental mass was biopsied under ultrasound guidance, and histopathology revealed non-necrotising granulomas. Sputum cultures and omental biopsy cultures subsequently grew Mycobacterium tuberculosis, and a diagnosis was made of pulmonary TB with TB peritonitis. The patient responded well to the initiation of anti-TB treatment.

Case of streptococcal toxic shock syndrome caused by rapidly progressive group A hemolytic streptococcal infection during postoperative chemotherapy for cervical cancer.

Streptococcal toxic shock syndrome (STSS) is a severe infectious disease caused by group A hemolytic streptococcus (Streptococcus pyogenes). This condition is a serious disease that involves rapidly progressive septic shock. We experienced a case of STSS caused by primary peritonitis during treatment with paclitaxel and cisplatin (TP therapy) as postoperative chemotherapy for cervical cancer. STSS mostly develops after extremity pain, but initial influenza-like symptoms of fever, chill, myalgia and gastrointestinal symptoms may also occur. TP therapy is used to treat many cancers, including gynecological cancer, but may cause adverse reactions of neuropathy and nephrotoxicity and sometimes fever, arthralgia, myalgia, abdominal pain and general malaise. The case reported here indicates that development of STSS can be delayed after chemotherapy and that primary STSS symptoms may be overlooked because they may be viewed as adverse reactions to chemotherapy. To our knowledge, this is the first report of a case of STSS during chemotherapy.

Plasma lipopolysaccharide is closely associated with glycemic control and abdominal obesity: evidence from bariatric surgery.

OBJECTIVE: It is of vital importance to elucidate the triggering factors of obesity and type 2 diabetes to improve patient care. Bariatric surgery has been shown to prevent and even cure diabetes, but the mechanism is unknown. Elevated levels of lipopolysaccharide (LPS) predict incident diabetes, but the sources of LPS are not clarified. The objective of the current study was to evaluate the potential impact of plasma LPS on abdominal obesity and glycemic control in subjects undergoing bariatric surgery. RESEARCH DESIGN AND METHODS: This was a prospective observational study involving a consecutive sample of 49 obese subjects undergoing bariatric surgery and 17 controls. Main assessments were plasma LPS, HbA1c, adipose tissue volumes (computed tomography), and quantified bacterial DNA in adipose tissue compartments. RESULTS: Plasma levels of LPS were elevated in obese individuals compared with controls (P < 0.001) and were reduced after bariatric surgery (P = 0.010). LPS levels were closely correlated with HbA1c (r = 0.56; P = 0.001) and intra-abdominal fat volumes (r = 0.61; P < 0.001), but only moderately correlated with subcutaneous fat volumes (r = 0.33; P = 0.038). Moreover, there was a decreasing gradient (twofold) in bacterial DNA levels going from mesenteric via omental to subcutaneous adipose tissue compartments (P = 0.041). Finally, reduced LPS levels after bariatric surgery were directly correlated with a reduction in HbA1c (r = 0.85; P < 0.001). CONCLUSIONS: Our findings support a hypothesis of translocated gut bacteria as a potential trigger of obesity and diabetes, and suggest that the antidiabetic effects of bariatric surgery might be mechanistically linked to, and even the result of, a reduction in plasma levels of LPS.

Abdominal tuberculosis leading to portal vein thrombosis, mimicking peritoneal carcinomatosis and liver cirrhosis.

Abdominal tuberculosis is a rare infectious disease that can involve the peritoneum and lead to portal vein thrombosis and mimic peritoneal carcinomatosis. We report on a 43-year-old male patient with fatigue and progressive weight loss for two years. Ascites was the only pathologic finding in his physical examination and laboratory findings revealed only a mild anaemia with Ca-125 elevation. The ascitic fluid Adenosine deaminase (ADA) level was also elevated. Computed tomography revealed splenomegaly, a mesenteric mass measuring 3.5 cm and intra-abdominal lymphadenopathies at the hepatic hilum. Oesophagogastroduodenoscopy (EGD) revealed oesophageal varices which was also consistent with portal hypertension. Diagnostic laparotomy and biopsies obtained from the omentum and the lymph nodes revealed acid-fast staining tuberculosis bacilli.

[A model of intestinal infiltrate in conditions of chronic experiment].

A chronic intestinal infiltrate model, aiming at a typical inflammatory process simulation, was elaborated in experiment. As a result of experiment on 30 rabbits the quantity of colonies of various causative agents was established, which did not cause the abscess and peritonitis formation. While doing the operation in 60 rabbits chronic infiltrate was formed between abducting and adducting small intestine loops, its mesentery and big omentum; between abducting and adducting large intestine loops, its mesentery and big omentum. The infiltrate formation process was studied up on the 3, 7, 14th and 28th day. Dynamics of changes in microorganisms species and quantity were studied, using microbiological investigations data. The stages of chronic intestinal infiltrate formation were followed up, using histological investigations. Application of the method proposed have permitted to form a chronic infiltrate owing predicted course to reduce the experiment duration and the investigated animals quantity.

Pelvic tuberculosis mimicking ovarian malignancy: a case report.

BACKGROUND: Tuberculosis is quite prevalent in developing countries, including India. In the female genital tract, the fallopian tube is the most common site involved by the disease. CASE: A woman presented with infertility, menstrual irregularities, an abdominal mass, abdominal pain and weight loss. She was previously operated on for left ovarian germ cell tumor. The clinical, radiologic and histopathologic examination helped to reach the correct diagnosis. CONCLUSION: In a woman with a history of infertility, menstrual irregularities, an abdominal mass and weight loss, differentiation between malignancy and tuberculosis becomes difficult. These two possibilities should always be part of the differential diagnosis.

Isolation of Mycobacterium bolletii from human omentum after laparoscopic gastric banding.

Mycobacterium bolletii infection with band erosion complicating laparoscopic gastric banding is reported. A 33-year-old man developed right upper quadrant pain and an epigastric discharging lesion 4 weeks after revision of gastric banding for morbid obesity. Investigation revealed band erosion with infection of the omentum and the abdominal wall. The band was removed and M. bolletii was isolated and identified after DNA sequence analysis. To the best of our knowledge, this is the first case in which M. bolletii was isolated from a human omentum after complicated gastric banding surgery.