Crucial role of carbon monoxide as a regulator of diarrhea caused by cholera toxin: Evidence of direct interaction with toxin.

The present study evaluated the role of heme oxygenase 1 (HO-1)/carbon monoxide (CO) pathway in the cholera toxin-induced diarrhea and its possible action mechanism. The pharmacological modulation with CORM-2 (a CO donor) or Hemin (a HO-1 inducer) decreased the intestinal fluid secretion and Cl- efflux, altered by cholera toxin. In contrast, ZnPP (a HO-1 inhibitor) reversed the antisecretory effect of Hemin and potentiated cholera toxin-induced intestinal secretion. Moreover, CORM-2 also prevented the alteration of intestinal epithelial architecture and local vascular permeability promoted by cholera toxin. The intestinal absorption was not altered by any of the pharmacological modulators. Cholera toxin inoculation also increased HO-1 immunoreactivity and bilirubin levels, a possible protective physiological response. Finally, using fluorometric technique, ELISA assay and molecular docking simulations, we show evidence that CO directly interacts with cholera toxin, forming a complex that affects its binding to GM1 receptor, which help explain the antisecretory effect. Thus, CO is an essential molecule for protection against choleric diarrhea and suggests its use as a possible therapeutic tool.

Role of probiotics in preventing Clostridioides difficile infection in older adults: an integrative review.

Clostridioides difficile infection (CDI) is the leading cause of healthcare-associated diarrhea. This infection can particularly affect older adults, the most susceptible to CDI. Currently, the standard therapeutic measure is antibiotic therapy, which in turn increases the risk of recurrence of the infection by its collateral damage to the patient's microbiota. Probiotics are live microorganisms capable of maintaining balance in the intestinal microbiota. This study aims to perform an integrative review of the protective benefit of probiotics in CDI and diarrhea associated with C. difficile. The PubMed, Scopus, and Web of Science databases, the 10-year time cutoff, and the Prism Flow diagram were used for data collection. We observed no consensus among the studies; however, three of the seven evaluated studies demonstrated that the use of probiotics in older adults could contribute to reducing the incidence of hospital-onset CDI. We also found that the studies evaluated a wide variety of microorganisms, particularly Saccharomyces boulardii, associated with beneficial effects. More research is needed to understand the successful use of probiotics in the prevention of CDI in hospitalized older adults receiving antibiotics.

Montelukast as a treatment for refractory cutaneous lupus: A case series.

INTRODUCTION: There are no drugs specifically approved to treat cutaneous lupus. Inflammatory cells in lupus skin lesions can produce leukotrienes (LT), which promote tissue damage. In addition to hypersensitivity reactions, LT are also associated with cardiovascular diseases and elevated serum LT levels have been linked to worse atherosclerotic disease in lupus. Targeting LT could thus be an alternative to treat lupus. We present 4 cases of cutaneous lupus successfully treated with montelukast (MLK), a Cys-LT antagonist. METHODS: Four consecutive female systemic lupus erythematosus (SLE) patients with refractory skin lesions were treated with MLK (10 mg/d) in the Hospital Universitário Walter Cantídio of the Universidade Federal do Ceará. Skin lesions were scored using Revised Cutaneous LE Disease Area and Severity Index (RCLASI). Relative expression of the 5-lipoxigenase (ALOX5) and 15-lipoxigenase (ALOX15) genes was determined in peripheral blood cells (PBC) from lupus patients and 4 age-matched female controls. RESULTS: All patients experienced improvement of skin lesions measured using RCLASI scores within 2-12 weeks following initiation of MLK. The response was sustained for at least 3 months follow-up and no adverse events were recorded. ALOX5 but not ALOX15 gene expression was significantly (P = 0.0425) increased in PBC from SLE patients vs controls. CONCLUSION: This is the first report of a fast and sustained successful response of cutaneous lupus to MLK. Given its acceptable safety profile, our data encourage development of a randomized trial as an attempt to reposition MLK as a safe, affordable alternative to treat cutaneous lupus.

Analysis of the Immunoexpression of Opioid Receptors and their Correlation with Markers of Angiogenesis, Cell Proliferation and Apoptosis in Breast Cancer.

OBJECTIVE: Breast cancer is a disease of great concern. The prognosis of this tumor is related to its staging. Opioids are widely used to minimize pain in oncology clinics; however, the relationship between the administration of opioids and their effects on tumor cells has yet to be elucidated. Therefore, this study aimed to evaluate the immunoexpression of mu- (µ) and kappa- (κ) opioid receptors and their correlation with markers of angiogenesis, cell proliferation, and apoptosis in biopsies of breast tumors. METHODS: Demographic data, tumor characteristics, opioid use, and prognostic factors were collected from medical records. After the selection of the excisional biopsies, immunohistochemistry was performed for µ- and κ-opioid receptors, vascular endothelial growth factor (VEGF), Ki-67, and TUNEL. RESULTS: A significant predominance of Ki-67 and µ-opioid receptor immunoexpression in the lymph nodes was observed in patients administered opioid medications. The luminal A subtype showed higher apoptosis levels (TUNEL) compared to the luminal B subtype. Patients with T4 tumor who had recurrence demonstrated a reduced expression of κ-opioid receptors at the lymph node location. Correlation analyses between the µ and κ opioid markers, VEGF, Ki-67, and TUNEL showed that these findings are likely involved in the same mechanisms the cancer of T4 stage breast cancer. CONCLUSION: The κ-opioid receptor has a lower immunoexpression in nodal tumor metastasis with recurrence, whereas the µ-opioid receptor is directly related to expression of TUNEL-positive cells  in tumors and indirectly to Ki-67 in nodal metastasis. Neither of the two receptors was expressed in the primary tumor or nodal metastasis in relation to VEGF.

Role of Rutin in 5-Fluorouracil-Induced Intestinal Mucositis: Prevention of Histological Damage and Reduction of Inflammation and Oxidative Stress.

Intestinal mucositis, characterized by inflammatory and/or ulcerative processes in the gastrointestinal tract, occurs due to cellular and tissue damage following treatment with 5-fluorouracil (5-FU). Rutin (RUT), a natural flavonoid extracted from Dimorphandra gardneriana, exhibits antioxidant, anti-inflammatory, cytoprotective, and gastroprotective properties. However, the effect of RUT on inflammatory processes in the intestine, especially on mucositis promoted by antineoplastic agents, has not yet been reported. In this study, we investigated the role of RUT on 5-FU-induced experimental intestinal mucositis. Swiss mice were randomly divided into seven groups: Saline, 5-FU, RUT-50, RUT-100, RUT-200, Celecoxib (CLX), and CLX + RUT-200 groups. The mice were weighed daily. After treatment, the animals were euthanized and segments of the small intestine were collected to evaluate histopathological alterations (morphometric analysis); malondialdehyde (MDA), myeloperoxidase (MPO), and glutathione (GSH) concentrations; mast and goblet cell counts; and cyclooxygenase-2 (COX-2) activity, as well as to perform immunohistochemical analyses. RUT treatment (200 mg/kg) prevented 5-FU-induced histopathological changes and reduced oxidative stress by decreasing MDA concentrations and increasing GSH concentrations. RUT attenuated the inflammatory response by decreasing MPO activity, intestinal mastocytosis, and COX-2 expression. These results suggest that the COX-2 pathway is one of the underlying protective mechanisms of RUT against 5-FU-induced intestinal mucositis.

Troxerutin Prevents 5-Fluorouracil Induced Morphological Changes in the Intestinal Mucosa: Role of Cyclooxygenase-2 Pathway.

Intestinal mucositis is a common complication associated with 5-fluorouracil (5-FU), a chemotherapeutic agent used for cancer treatment. Troxerutin (TRX), a semi-synthetic flavonoid extracted from Dimorphandra gardneriana, has been reported as a potent antioxidant and anti-inflammatory agent. In the present study, we aimed to evaluate the effect of TRX on 5-FU-induced intestinal mucositis. Swiss mice were randomly divided into seven groups: Saline, 5-FU, TRX-50, TRX-100, TRX-150, Celecoxib (CLX), and CLX + TRX-100. The weight of mice was measured daily. After treatment, the animals were euthanized and segments of the small intestine were collected to evaluate histopathological alterations (morphometric analysis), levels of malondialdehyde (MDA), myeloperoxidase (MPO), glutathione (GSH), mast and goblet cell counts, immunohistochemical analysis, and cyclooxygenase-2 (COX-2) activity. Compared to the saline treatment, the 5-FU treatment induced intense weight loss and reduction in villus height. TRX treatment (100 mg/kg) prevented the 5-FU-induced histopathological changes and decreased oxidative stress by decreasing the MDA levels and increasing GSH concentration. TRX attenuated inflammatory process by decreasing MPO activity, intestinal mastocytosis, and COX-2 expression. TRX also reversed the depletion of goblet cells. Our findings suggest that TRX at a concentration of 100 mg/kg had chemopreventive effects on 5-FU-induced intestinal mucositis via COX-2 pathway.

Role of the route of leukotrienes in an experimental model of oral mucositis induced by 5-fluorouracil 1.

PURPOSE: To investigate the participation of cysteinyl leukotrienes in the pathophysiology of oral mucositis. METHODS: Oral mucositis was induced in hamsters using 5-fluorouracil (5-FU; 60 and 40 mg/kg; i.p., on days 1 and 2, respectively, and with excoriations in jugal mucosa on day 4). Montelukast (10, 20, or 40 mg/kg/d; gavage), MK886 (3 mg/kg/d, i.p.), or saline or celecoxib (7.5 mg/kg/d; i.p.) was administered 1 h prior to 5-FU and daily, until the fourth (MK886) or tenth day, when the animals were euthanized and their jugal mucosa was collected for macroscopic, histopathological, and immunohistochemical evaluation. RESULTS: Neither montelukast nor MK-886 prevented the oral mucositis induced by 5-FU, as observed by histopathological evaluation. In addition, we did not find significant differences in the expression of inducible nitric oxide synthase-2, cyclooxygenase-2, or interleukin (IL)-1ß between the experimental and control groups. However, we did observe a significant decrease in tumor necrosis factor (TNF)-α expression for all doses of montelukast; we also observed a significant decrease in IL-10 with 40 mg/kg/d and MK 886. CONCLUSIONS: Cysteinyl leukotrienes do not play an important role in experimental oral mucositis induced by 5-FU. There is a modulating action specifically on TNF-α.

Role of the route of leukotrienes in an experimental model of oral mucositis induced by 5-fluorouracil

Abstract Purpose: To investigate the participation of cysteinyl leukotrienes in the pathophysiology of oral mucositis. Methods: Oral mucositis was induced in hamsters using 5-fluorouracil (5-FU; 60 and 40 mg/kg; i.p., on days 1 and 2, respectively, and with excoriations in jugal mucosa on day 4). Montelukast (10, 20, or 40 mg/kg/d; gavage), MK886 (3 mg/kg/d, i.p.), or saline or celecoxib (7.5 mg/kg/d; i.p.) was administered 1 h prior to 5-FU and daily, until the fourth (MK886) or tenth day, when the animals were euthanized and their jugal mucosa was collected for macroscopic, histopathological, and immunohistochemical evaluation. Results: Neither montelukast nor MK-886 prevented the oral mucositis induced by 5-FU, as observed by histopathological evaluation. In addition, we did not find significant differences in the expression of inducible nitric oxide synthase-2, cyclooxygenase-2, or interleukin (IL)-1β between the experimental and control groups. However, we did observe a significant decrease in tumor necrosis factor (TNF)-α expression for all doses of montelukast; we also observed a significant decrease in IL-10 with 40 mg/kg/d and MK 886. Conclusions: Cysteinyl leukotrienes do not play an important role in experimental oral mucositis induced by 5-FU. There is a modulating action specifically on TNF-α.

Effect of Remote Ischemic Preconditioning on Systemic Toxicity and Ototoxicity Induced by Cisplatin in Rats: Role of TNF-α and Nitric Oxide.

BACKGROUND/AIMS: Cisplatin is a chemotherapeutic agent. The use of remote ischemic preconditioning (RIPC) was proposed after the observation that ischemic preconditioning of a cardiac vascular area could protect another completely distinctly. METHODS: This is an experimental study. Male Wistar rats were anesthetized, and they underwent a hearing evaluation via measurement of the brainstem auditory evoked potential (BSAEP). Then, cisplatin was administered intraperitoneally (IP) at a dose of 8 mg/kg/day for 4 consecutive days to group 1, whereas saline solution was administered IP to group 2. In groups 3 and 4, ischemia of the right hind paw was performed for 10 min, followed by reperfusion for 30 min, after which cisplatin or saline was administered IP to group 3 or group 4, respectively. Afterwards, all animals were evaluated via the BSAEP. The right cochlea was dissected for immunohistochemistry. RESULTS: RIPC lowered the increase in BSAEP of the animals treated with cisplatin (p = 0.0146). Weight loss decreased in the animals subjected to RIPC (p < 0.005). In group 3, RIPC reversed immunostaining for tumor necrosis factor-α and inducible nitric oxide synthase in the stria vascularis injured by cisplatin (p < 0.05). CONCLUSION: RIPC protects against systemic toxicity and ototoxicity induced by cisplatin in rats.

Red propolis ameliorates ischemic-reperfusion acute kidney injury.

INTRODUCTION: Acute kidney injury (AKI) remains a great problem in clinical practice. Renal ischemia/reperfusion (I/R) injury is a complex pathophysiological process. Propolis is a natural polyphenol-rich resinous substance collected by honeybees from a variety of plant sources that has anti-inflammatory and anti-oxidative properties. Red propolis (RP) protection in renal I/R injury was investigated. METHODS: Male Wistar rats underwent unilateral nephrectomy and contralateral renal I/R (60 min). Rats were divided into four groups: (1) sham group, (2) RP group (sham-operated rats treated with RP), 3) IR group (rats submitted to ischemia) and (4) IR-RP (rats treated with RP before ischemia). At 48 h after reperfusion, renal function was assessed and kidneys were removed for analysis. RESULTS: I/R increased plasma levels of creatinine and reduced creatinine clearance (CrCl), and RP provided protection against this renal injury. Red propolis significantly improves oxidative stress parameters when compared with the IR group. Semiquantitative assessment of the histological lesions showed marked structural damage in I/R rats compared with the IR-RP rats. RP attenuates I/R-induced endothelial nitric oxide-synthase down regulation and increased heme-oxygenase expression in renal tissue. CONCLUSION: Red propolis protects kidney against acute ischemic renal failure and this protection is associated with reduced oxidative stress and eNOS and heme-oxygenase up regulation.