Successful Pre-Clinical Management of Irinotecan-Debilitated Animals: A Protein- Based Accessory Phytomedicine.

BACKGROUND: Calotropis procera is a laticiferous plant (Apocynaceae) found in tropical regions all over the world. The ultrastructural characteristics of laticifers, their restricted distribution among different taxonomic groups, and in some species in each clade, as peptidases from latex, make them very attractive for biological analysis. OBJECTIVE: The study aims to investigate the effects of LP-PII-IAA (laticifer protein (LP) sub-fraction II (PII) of C. procera presenting an iodoacetamide-inhibited cysteine proteinase activity) on irinotecan-induced intestinal mucositis, a serious adverse effect of this medicine for the treatment of cancer. METHODS: LP-PII-IAA is composed of closely related isoforms (90%) of peptidases derived from catalysis and an osmotin protein (5%). Animals receiving co-administration of LP-PII-IAA presented a significant decrease in mortality, absence of diarrhea, histological preservation, and normalization of intestinal functions. RESULTS: Clinical homeostasis was accompanied by a reduction in MPO activity and declined levels of IL-1ß, IL-6 and KC, while the IL-10 level increased in LP-PII-IAA-treated animals. COX-2 and NF-kB immunostaining was reduced and the levels of oxidative markers (GSH, MDA) were normalized in animals that received LP-PII-IAA. CONCLUSION: We suggest that peptidases from the latex of Calotropis procera were instrumental in the suppression of the adverse clinical and physiological effects of irinotecan.

Topical protection of mice laryngeal mucosa using the natural product cashew gum.

OBJECTIVES/HYPOTHESIS: Evaluate the effect of in vitro exposure of mice laryngeal mucosa to solutions that simulated human gastric juice and to assess the topical protective effect of cashew gum on mice laryngeal mucosal integrity in vitro. STUDY DESIGN: Animal study. METHODS: Murine (Swiss) laryngeal samples were mounted in Ussing chambers. The luminal side of biopsies was exposed to solutions of different acidity with or without pepsin and/or taurodeoxycholic acid (TDC). Transepithelial electrical resistance (TER) was continuously recorded. The topical protective effect of cashew gum solution was evaluated by precoating the biopsies before the exposure with a solution at pH 5 containing 5 mM TDC. Changes in TER and mucosal permeability to fluorescein were measured. RESULTS: Exposure of laryngeal mucosa to acidic solutions containing pepsin and TDC provoked a pH-dependent drop in TER with the maximal effect at pH 1, but still present at pH 5 (weakly acidic). The exposure of the laryngeal mucosa to a solution of pH 5 with TDC, but not with pepsin, produced a dose-dependent decrease in TER. Precoating the mucosa with cashew gum prevented the reduction of TER and increased transepithelial permeability by exposure to a solution at pH5 containing TDC. CONCLUSIONS: Weakly acidic solutions containing bile acids can produce impairment of laryngeal epithelial barrier, which may be protected by topical treatment with cashew gum. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:1157-1162, 2018.

Anti-inflammatory effect of the monoterpene myrtenol is dependent on the direct modulation of neutrophil migration and oxidative stress.

Myrtenol is a bicyclic monoterpene with anti-inflammatory properties. However, the mechanisms involved are partially unknown. Here, we investigated the effect of myrtenol during experimental chronic arthritis and the possible modulating activity of oxidative stress and neutrophil migration. Complete Freund's Adjuvant (CFA)-sensitized rats were treated with vehicle (1 mL/kg, po), myrtenol (12.5, 25 or 50 mg/kg, po), indomethacin (10 mg/kg, po) or dexamethasone (0.4 mg/kg) followed by intra-articular injection of CFA (0.5 mg/mL, 50 µL per joint). Then, paw edema and articular incapacitation (paw elevation time) were evaluated for 14 days. On the last day, a blood concentration superoxide dismutase (SOD) and nitrite was determined. In another experimental setting, human neutrophils were incubated with vehicle (sterile saline, 1 mL) or myrtenol (10-100 ng/mL) and the in vitro chemotaxis to N-formylmethionine-leucyl-phenylalanine (fMLP) (10-7 M/well) was evaluated. In addition, antiinflammatory effect of myrtenol was investigated in carrageenan-induced peritonitis. We found that CFA induced a prominent paw swelling and incapacitation of the joint, which were significantly prevented by myrtenol (P < 0.05). In addition, blood accumulation nitrite was attenuated by myrtenol when compared with vehicle-treated CFA group (P < 0.05). Furthermore, plasma levels of SOD were significantly increased by myrtenol versus vehicle-treated CFA group (P < 0.05). Moreover, fMLP-triggered neutrophil chemotaxis and carrageenan-induced peritonitis were markedly prevented by myrtenol (P < 0.05). Therefore, myrtenol showed anti-inflammatory and antinociceptive effects on experimental chronic arthritis, which seems to be related to the direct modulation of neutrophil migration and antioxidant activity.

Irinotecan- and 5-fluorouracil-induced intestinal mucositis: insights into pathogenesis and therapeutic perspectives.

PURPOSE: Intestinal mucositis and diarrhea are common manifestations of anticancer regimens that include irinotecan, 5-fluorouracil (5-FU), and other cytotoxic drugs. These side effects negatively impact therapeutic outcomes and delay subsequent cycles of chemotherapy, resulting in dose reductions and treatment discontinuation. Here, we aimed to review the experimental evidence regarding possible new targets for the management of irinotecan- and 5-FU-related intestinal mucositis. METHODS: A literature search was performed using the PubMed and MEDLINE databases. No publication time limit was set for article inclusion. RESULTS: Here, we found that clinical management of intestinal mucositis and diarrhea is somewhat ineffective at reducing symptoms, possibly due to a lack of specific targets for modulation. We observed that IL-1ß contributes to the apoptosis of enterocytes in mucositis induced by 5-FU. However, 5-FU-related mucositis is far less thoroughly investigated with regard to specific molecular targets when compared to irinotecan-related disease. Several studies have proposed that a correlation exists between the intestinal microbiota, the enterohepatic recirculation of active metabolites of irinotecan, and the establishment of mucositis. However, as reviewed here, this association seems to be controversial. In addition, the pathogenesis of irinotecan-induced mucositis appears to be orchestrated by interleukin-1/Toll-like receptor family members, leading to epithelial cell apoptosis. CONCLUSIONS: IL-1ß, IL-18, and IL-33 and the receptors IL-1R, IL-18R, ST2, and TLR-2 are potential therapeutic targets that can be modulated to minimize anticancer agent-associated toxicity, optimize cancer treatment dosing, and improve clinical outcomes. In this context, the pathogenesis of mucositis caused by other anticancer agents should be further investigated.

α-Phellandrene, a cyclic monoterpene, attenuates inflammatory response through neutrophil migration inhibition and mast cell degranulation.

AIMS: We aimed to investigate the modulating effect of α-phellandrene on neutrophil migration and mast cell degranulation processes. MAIN METHODS: Male Wistar rats or Swiss mice were treated p.o. with vehicle (3% Tween 80, p.o.), α-phellandrene (50, 100, or 200mg/kg, p.o.), or dexamethasone (0.5mg/kg, p.o.) 1h before carrageenan injection. Then, the neutrophil migration in 6-day-old air pouches or peritoneal cavities. The leukocyte rolling and adhesion were measured in real time and assessed by intravital microscopy. ELISA was used to detect TNF-α and IL-6 in peritoneal lavage. Compound 48/80-induced mast cell degranulation was assessed in mesenteric rat tissues. KEY FINDINGS: In all the tested doses, α-phellandrene prevented carrageenan-induced neutrophil accumulation (P<0.05). As detected by intravital microscopy, α-phellandrene also inhibited leukocyte rolling and adhesion, as well as significantly inhibited the production of the pro-inflammatory cytokines TNF-α and IL-6. Moreover, the degranulation of compound 48/80-induced mast cells was also inhibited by α-phellandrene (P<0.001). SIGNIFICANCE: These results suggest that α-phellandrene plays an important role as an anti-inflammatory agent through neutrophil migration modulation and mast cell stabilization.

Correction: Topical HPMC/S-Nitrosoglutathione Solution Decreases Inflammation and Bone Resorption in Experimental Periodontal Disease in Rats.

[This corrects the article DOI: 10.1371/journal.pone.0153716.].

Topical HPMC/S-Nitrosoglutathione Solution Decreases Inflammation and Bone Resorption in Experimental Periodontal Disease in Rats.

S-nitrosoglutathione (GSNO) is a nitric oxide (NO) donor, which exerts antioxidant, anti-inflammatory, and microbicidal actions. Intragingival application of GSNO was already shown to decrease alveolar bone loss, inflammation and oxidative stress in an experimental periodontal disease (EPD) model. In the present study, we evaluated the potential therapeutic effect of topical applications of hydroxypropylmethylcellulose (HPMC)/GSNO solutions on EPD in Wistar rats. EPD was induced by placing a sterilized nylon (3.0) thread ligature around the cervix of the second left upper molar of the animals, which received topical applications of a HPMC solutions containing GSNO 2 or 10 mM or vehicle (HPMC solution), 1 h prior to the placement of the ligature and then twice daily until sacrifice on day 11. Treatment with HPMC/GSNO 10 mM solution significantly reduced alveolar bone loss, oxidative stress and TNF-α e IL-1ß levels in the surrounding gingival tissue, and led to a decreased transcription of RANK and TNF-α genes and elevated bone alkaline phosphatase, compared to the HPMC group. In conclusion, topical application of HPMC/GSNO solution is a potential treatment to reduce inflammation and bone loss in periodontal disease.

A new animal model of intestinal mucositis induced by the combination of irinotecan and 5-fluorouracil in mice.

PURPOSE: Intestinal mucositis (IM) is a common side effect of anticancer agents. Despite polychemotherapy use in clinical practice, the pathogenesis of IM has been investigated in single drug injection animal models. However, the progression of IM could vary according to drug regimens. Thus, we aimed to develop a new experimental mucositis model induced by combining irinotecan and 5-fluorouracil (5-FU) treatments. METHODS: IM was induced in male C57BL/6 mice by the intraperitoneal administration of either 0.9 % saline (5 mL/kg), irinotecan (IRI, 30 or 45 mg/kg), 5-FU (25, 37.5, or 50 mg/kg), or the combination of these doses (IRI + 5-FU) for 4 days. Animal survival, body mass variation, and diarrhea scores were evaluated daily. On the 7th day, the mice were euthanized, and intestinal samples were collected for histopathology and morphometric analysis, as well as for the determination of myeloperoxidase activity and cytokine dosage (TNF-α and IL-6). RESULTS: The optimal dose combination that induced IM and presented no substantial mortality on the 7th day was IRI (45 mg/kg) + 5-FU (37.5 mg/kg), which was used for subsequent studies. IRI and 5-FU in combination induced significant diarrhea, body weight loss, intestinal damage, inflammatory cell infiltration, and increased levels of cytokines when compared with other groups (P < 0.05). Neither IRI nor 5-FU alone induced IM. CONCLUSIONS: We developed a new experimental model of IM induced by combining irinotecan and 5-FU treatments, which will allow us to gain a better knowledge concerning the pathogenesis of this disease through the pharmacological modulation of key inflammatory mediators.

The Adaptor Protein Myd88 Is a Key Signaling Molecule in the Pathogenesis of Irinotecan-Induced Intestinal Mucositis.

Intestinal mucositis is a common side effect of irinotecan-based anticancer regimens. Mucositis causes cell damage, bacterial/endotoxin translocation and production of cytokines including IL-1 and IL-18. These molecules and toll-like receptors (TLRs) activate a common signaling pathway that involves the Myeloid Differentiation adaptor protein, MyD88, whose role in intestinal mucositis is unknown. Then, we evaluated the involvement of TLRs and MyD88 in the pathogenesis of irinotecan-induced intestinal mucositis. MyD88-, TLR2- or TLR9-knockout mice and C57BL/6 (WT) mice were given either saline or irinotecan (75 mg/kg, i.p. for 4 days). On day 7, animal survival, diarrhea and bacteremia were assessed, and following euthanasia, samples of the ileum were obtained for morphometric analysis, myeloperoxidase (MPO) assay and measurement of pro-inflammatory markers. Irinotecan reduced the animal survival (50%) and induced a pronounced diarrhea, increased bacteremia, neutrophil accumulation in the intestinal tissue, intestinal damage and more than twofold increased expression of MyD88 (200%), TLR9 (400%), TRAF6 (236%), IL-1ß (405%), IL-18 (365%), COX-2 (2,777%) and NF-κB (245%) in the WT animals when compared with saline-injected group (P<0.05). Genetic deletion of MyD88, TLR2 or TLR9 effectively controlled the signs of intestinal injury when compared with irinotecan-administered WT controls (P<0.05). In contrast to the MyD88-/- and TLR2-/- mice, the irinotecan-injected TLR9-/- mice showed a reduced survival, a marked diarrhea and an enhanced expression of IL-18 versus irinotecan-injected WT controls. Additionally, the expression of MyD88 was reduced in the TLR2-/- or TLR9-/- mice. This study shows a critical role of the MyD88-mediated TLR2 and TLR9 signaling in the pathogenesis of irinotecan-induced intestinal mucositis.

Target Inhibition of IL-1 Receptor Prevents Ifosfamide Induced Hemorrhagic Cystitis in Mice.

PURPOSE: Hemorrhagic cystitis is an important dose limiting side effect of ifosfamide based cancer chemotherapy. Despite chemoprophylaxis inflammation can still be found in cystoscopy guided biopsies. Previous studies confirmed the role of TNF-α and IL-1ß. We evaluated the protective effect of the IL-1R antagonist anakinra and the anti-TNF-α antibody infliximab in experimental ifosfamide induced hemorrhagic cystitis. MATERIALS AND METHODS: Hemorrhagic cystitis was induced by an injection of ifosfamide (400 mg/kg intraperitoneally) in Swiss wild-type C57Bl/6, IL-1R-/-, TNFR1-/- or TNFR1/R2-/- mice. Mice were treated 30 minutes before ifosfamide with anakinra (100 mg/kg intraperitoneally), infliximab (5 mg/kg intraperitoneally) or vehicle. Visceral nociception was evaluated after hemorrhagic cystitis induction. At 12 hours the animals were sacrificed. Bladders were harvested to assess bladder wet weight, vascular permeability, macroscopic and microscopic findings, muscle contractility, and for cystometrography. Inflammatory cell infiltration was assessed by myeloperoxidase assay and flow cytometry. RESULTS: Anakinra attenuated hemorrhage, edema, neutrophil infiltration, visceral hyperalgesia and bladder dysfunction. IL-1R-/- mice also showed milder hemorrhagic cystitis. Infliximab inhibited bladder edema and visceral hyperalgesia without preventing hemorrhage, bladder dysfunction, neutrophils or accumulation. Additionally, the lack of TNFR1 decreased bladder edema but not cell infiltration whereas concomitant deficiency of TNFR1 and TNFR2 resulted in worse hemorrhagic cystitis. CONCLUSIONS: Anakinra is effective for preventing experimentally ifosfamide induced hemorrhagic cystitis. It seems that neutrophil and macrophage infiltration in this circumstance depends on IL-1 signaling through IL1R. Possibly TNFR2 has a protective role in hemorrhagic cystitis.

Alendronate induces gastric damage by reducing nitric oxide synthase expression and NO/cGMP/K(ATP) signaling pathway.

Chronic use of alendronate has been linked to gastrointestinal tract problems. Our objective was to evaluate the role of the NO/cGMP/KATP signaling pathway and nitric oxide synthase expression in alendronate-induced gastric damage. Rats were either treated with the NO donor, sodium nitroprusside (SNP; 1, 3, and 10 mg/kg), or the NO synthase (NOS) substrate, L-arginine (L-Arg; 50, 100, and 200 mg/kg). Some rats were pretreated with either ODQ (a guanylate cyclase inhibitor; 10 mg/kg) or glibenclamide (KATP channels blocker; 10 mg/kg). In other experiments, rats were pretreated with L-NAME (non-selective NOS inhibitor; 10 mg/kg), 1400 W (selective inducible NOS [iNOS] inhibitor; 10 mg/kg), or L-NIO (a selective endothelial NOS [eNOS] inhibitor; 30 mg/kg). After 1 h, the rats were treated with alendronate (30 mg/kg) by gavage for 4 days. SNP and L-Arg prevented alendronate-induced gastric damage in a dose-dependent manner. Alendronate reduced nitrite/nitrate levels, an effect that was reversed with SNP or L-Arg treatment. Pretreatment with ODQ or glibenclamide reversed the protective effects of SNP and L-Arg. L-NAME, 1400 W, or L-NIO aggravated the severity of alendronate-induced lesions. In addition, alendronate reduced the expression of iNOS and eNOS in the gastric mucosa. Gastric ulcerogenic responses induced by alendronate were mediated by a decrease in NO derived from both eNOS and iNOS. In addition, our findings support the hypothesis that activation of the NO/cGMP/KATP pathway is of primary importance for protection against alendronate-induced gastric damage.