Effect of the Cannabinoid Agonist WIN 55,212-2 on Neuropathic and Visceral Pain Induced by a Non-Diarrheagenic Dose of the Antitumoral Drug 5-Fluorouracil in the Rat.

5-fluorouracil (5-FU) is an antineoplastic drug used to treat colorectal cancer, but it causes, among other adverse effects, diarrhea and mucositis, as well as enteric neuropathy, as shown in experimental animals. It might also cause neuropathic pain and alterations in visceral sensitivity, but this has not been studied in either patients or experimental animals. Cannabinoids have antimotility and analgesic effects and may alleviate 5-FU-induced adverse effects. Our aim was to evaluate the effects of the cannabinoid agonist WIN 55,212-2 on neuropathic and visceral pain induced by a non-diarrheagenic dose of 5-FU. Male Wistar rats received a dose of 5-FU (150 mg/kg, ip) and gastrointestinal motility, colonic sensitivity, gut wall structure and tactile sensitivity were evaluated. WIN 55,212-2 (WIN) was administered to evaluate its effect on somatic (50-100 µg ipl; 1 mg/kg, ip) and visceral (1 mg/kg, ip) sensitivity. The cannabinoid tetrad was used to assess the central effects of WIN (1 mg/kg, ip). 5-FU decreased food intake and body weight gain, produced mucositis and thermal hyperalgesia, but these effects were reduced afterwards, and were not accompanied by diarrhea. Tactile mechanical allodynia was also evident and persisted for 15 days. Interestingly, it was alleviated by WIN. 5-FU tended to increase colonic sensitivity whereas WIN reduced the abdominal contractions induced by increasing intracolonic pressure in both control and 5-FU-treated animals. Importantly, the alleviating effects of WIN against those induced by 5-FU were not accompanied by any effect in the cannabinoid tetrad. The activation of the peripheral cannabinoid system may be useful to alleviate neuropathic and visceral pain associated with antitumoral treatment.

Probiotics and Probiotic-like Agents against Chemotherapy-Induced Intestinal Mucositis: A Narrative Review.

Cancer chemotherapy has allowed many patients to survive, but not without risks derived from its adverse effects. Drugs, such as 5-fluorouracil, irinotecan, oxaliplatin, methotrexate, and others, as well as different drug combinations trigger intestinal mucositis that may cause or contribute to anorexia, pain, diarrhea, weight loss, systemic infections, and even death. Dysbiosis is a hallmark of chemotherapy-induced intestinal mucositis and diarrhea, and, therefore, strategies aimed at modulating intestinal microbiota may be useful to counteract and prevent those dreadful effects. This narrative review offers an overview of the studies performed to test the efficacy of probiotics and probiotic-like agents against chemotherapy-induced intestinal mucositis and its consequences. Microbiota modulation through the oral administration of different probiotics (mainly strains of Lactobacillus and Bifidobacterium), probiotic mixtures, synbiotics, postbiotics, and paraprobiotics has been tested in different animal models and in some clinical trials. Regulation of dysbiosis, modulation of epithelial barrier permeability, anti-inflammatory effects, modulation of host immune response, reduction of oxidative stress, or prevention of apoptosis are the main mechanisms involved in their beneficial effects. However, the findings are limited by the great heterogeneity of the preclinical studies and the relative lack of studies in immunocompromised animals, as well as the scarce availability of results from clinical trials. Despite this, the results accumulated so far are promising. Hopefully, with the aid of these agents, intestinal mucositis will be less impactful to the cancer patient in the near future.

Contractility of isolated colonic smooth muscle strips from rats treated with cancer chemotherapy: differential effects of cisplatin and vincristine.

Background: Certain antineoplastic drugs cause gastrointestinal disorders even after the end of treatment. Enteric neuropathy has been associated with some of these alterations. Our goal was to assess the impact of repeated treatment with cisplatin and vincristine on the contractility of circular and longitudinal muscle strips isolated from the rat colon. Methods: Two cohorts of male rats were used: in cohort 1, rats received one intraperitoneal (ip) injection of saline or cisplatin (2 mg kg-1 week-1) on the first day of weeks 1-5; in cohort 2, rats received two cycles of five daily ip injections (Monday to Friday, weeks 1-2) of saline or vincristine (0.1 mg kg-1 day-1). Body weight and food and water intake were monitored throughout the study. One week after treatment, responses of colonic smooth muscle strips to acetylcholine (10-9-10-5 M) and electrical field stimulation (EFS, 0.1-20 Hz), before and after atropine (10-6 M), were evaluated in an organ bath. Results: Both drugs decreased body weight gain. Compared to saline, cisplatin significantly decreased responses of both longitudinal and circular smooth muscle strips to EFS, whereas vincristine tended to increase them, although in a non-significant manner. No differences were observed in the muscle response to acetylcholine. Atropine abolished the contractile responses induced by acetylcholine, although those induced by EFS were only partially reduced in the presence of atropine. Conclusion: The findings suggest that although both drugs cause the development of enteric neuropathy, this seems to have a functional impact only in cisplatin-treated animals. Understanding the effects of chemotherapy on gastrointestinal motor function is vital for enhancing the quality of life of cancer patients.

Mechanisms of Chemotherapy-Induced Neurotoxicity.

Since the first clinical trials conducted after World War II, chemotherapeutic drugs have been extensively used in the clinic as the main cancer treatment either alone or as an adjuvant therapy before and after surgery. Although the use of chemotherapeutic drugs improved the survival of cancer patients, these drugs are notorious for causing many severe side effects that significantly reduce the efficacy of anti-cancer treatment and patients' quality of life. Many widely used chemotherapy drugs including platinum-based agents, taxanes, vinca alkaloids, proteasome inhibitors, and thalidomide analogs may cause direct and indirect neurotoxicity. In this review we discuss the main effects of chemotherapy on the peripheral and central nervous systems, including neuropathic pain, chemobrain, enteric neuropathy, as well as nausea and emesis. Understanding mechanisms involved in chemotherapy-induced neurotoxicity is crucial for the development of drugs that can protect the nervous system, reduce symptoms experienced by millions of patients, and improve the outcome of the treatment and patients' quality of life.

Cannabinoid drugs against chemotherapy-induced adverse effects: focus on nausea/vomiting, peripheral neuropathy and chemofog in animal models.

Although new drugs are being developed for cancer treatment, classical chemotherapeutic agents are still front-line therapies, despite their frequent association with severe side effects that can hamper their use. Cannabinoids may prevent or palliate some of these side effects. The aim of the present study is to review the basic research which has been conducted evaluating the effects of cannabinoid drugs in the treatment of three important side effects induced by classical chemotherapeutic agents: nausea and vomiting, neuropathic pain and cognitive impairment. Several published studies have demonstrated that cannabinoids are useful in preventing and reducing the nausea, vomits and neuropathy induced by different chemotherapy regimens, though other side effects can occur, such as a reduction of gastrointestinal motility, along with psychotropic effects when using centrally-acting cannabinoids. Thus, peripherally-acting cannabinoids and new pharmacological options are being investigated, such as allosteric or biased agonists. Additionally, due to the increase in the survival of cancer patients, there are emerging data that demonstrate an important cognitive deterioration due to chemotherapy, and because the cannabinoid drugs have a neuroprotective effect, they could be useful in preventing chemotherapy-induced cognitive impairment (as demonstrated through studies in other neurological disorders), but this has not yet been tested. Thus, although cannabinoids seem a promising therapeutic approach in the treatment of different side effects induced by chemotherapeutic agents, future research will be necessary to find pharmacological options with a safer profile. Moreover, a new line of research awaits to be opened to elucidate their possible usefulness in preventing cognitive impairment.

Lipidomics as Tools for Finding Biomarkers of Intestinal Pathology: From Irritable Bowel Syndrome to Colorectal Cancer.

Lipidomics is an emerging and promising omic that analyzes different lipid molecules in a biological sample. It is considered as a branch of metabolomics, which is defined as the comprehensive analysis of metabolites in a biological specimen. Nonetheless, in recent years lipidomics is being considered a distinct discipline in the biomedicine field. Lipids play important roles in many biological pathways and could work as biomarkers of disease or as therapeutic targets for treatment diseases. The major lipidomics strategies are shotgun lipidomics and liquid chromatography coupled with mass spectrometry. Gastrointestinal diseases such as irritable bowel syndrome or inflammatory bowel disease are chronic diseases that need non-invasive biomarkers for prognosis and diagnosis. Even more, patients with inflammatory bowel disease are at a significantly increased risk of colorectal cancer, principally resulting from the pro-neoplastic effects of chronic intestinal inflammation. Current screening methods utilized globally include sigmoidoscopy, or standard colonoscopy but it is important to develop non-invasive and accurate screening tools to facilitate early detection and precise staging of colorectal cancer. Disease progression and response to treatment may benefit also from the application of these potential new tools. This review is focused on studies that use lipidomics approaches to discover potential biomarkers for monitoring the mentioned intestinal diseases and, particularly, tumour progression.

Cannabinoid Drugs-Related Neuroprotection as a Potential Therapeutic Tool Against Chemotherapy-Induced Cognitive Impairment.

In recent years, and particularly associated with the increase of cancer patients' life expectancy, the occurrence of cancer treatment sequelae, including cognitive impairments, has received considerable attention. Chemotherapy-induced cognitive impairments (CICI) can be observed not only during pharmacological treatment of the disease but also long after cessation of this therapy. The lack of effective tools for its diagnosis together with the limited treatments currently available for alleviation of the side-effects induced by chemotherapeutic agents, demonstrates the need of a better understanding of the mechanisms underlying the pathology. This review focuses on the comprehensive appraisal of two main processes associated with the development of CICI: neuroinflammation and oxidative stress, and proposes the endogenous cannabinoid system (ECS) as a new therapeutic target against CICI. The neuroprotective role of the ECS, well described in other cognitive-related neuropathologies, seems to be able to reduce the activation of pro-inflammatory cytokines involved in the neuroinflammatory supraspinal processes underlying CICI. This review also provides evidence supporting the role of cannabinoid-based drugs in the modulation of oxidative stress processes that underpin cognitive impairments, and warrant the investigation of endocannabinoid components, still unknown, that may mediate the molecular mechanism behind this neuroprotective activity. Finally, this review points forward the urgent need of research focused on the understanding of CICI and the investigation of new therapeutic targets.

Antiproliferative and palliative activity of flavonoids in colorectal cancer.

Flavonoids are plant bioactive compounds of great interest in nutrition and pharmacology, due to their remarkable properties as antioxidant, anti-inflammatory, antibacterial, antifungal and antitumor drugs. More than 5000 different flavonoids exist in nature, with a huge structural diversity and a plethora of interesting pharmacological properties. In this work, five flavonoids were tested for their potential use as antitumor drugs against three CRC cell lines (HCT116, HT-29 and T84). These cell lines represent three different stages of this tumor, one of which is metastatic. Xanthohumol showed the best antitumor activity on the three cancer cell lines, even better than that of the clinical drug 5-fluorouracil (5-FU), although no synergistic effect was observed in the combination therapy with this drug. On the other hand, apigenin and luteolin displayed slightly lower antitumor activities on these cancer cell lines but showed a synergistic effect in combination with 5-FU in the case of HTC116, which is of potential clinical interest. Furthermore, a literature review highlighted that these flavonoids show very interesting palliative effects on clinical symptoms such as diarrhea, mucositis, neuropathic pain and others often associated with the chemotherapy treatment of CRC. Flavonoids could provide a double effect for the combination treatment, potentiating the antitumor effect of 5-FU, and simultaneously, preventing important side effects of 5-FU chemotherapy.

Effects of the food additive monosodium glutamate on cisplatin-induced gastrointestinal dysmotility and peripheral neuropathy in the rat.

BACKGROUND: Cisplatin is an antineoplastic drug known to produce intense vomiting, gastric dysmotility, and peripheral neuropathy. Monosodium glutamate (MSG) is a flavor enhancer with prokinetic properties potentially useful for cancer patients under chemotherapy. Our aim was to test whether MSG may improve gastrointestinal motor dysfunction and other adverse effects induced by repeated cisplatin in rats. METHODS: Male Wistar rats were exposed or not to MSG (4 g L-1 ) in drinking water from week 0 to 1 week after treatment. On the first day of weeks 1-5, rats were treated with saline or cisplatin (2 mg kg-1  week-1 , ip). Gastrointestinal motility was measured by radiological methods after first and fifth administrations, as well as 1 week after treatment finalization. One week after treatment, the threshold for mechanical somatic sensitivity was recorded. Finally, samples of stomach, terminal ileum and kidneys were evaluated in sections using conventional histology. The myenteric plexus was immunohistochemically evaluated on distal colon whole-mount preparations. KEY RESULTS: Monosodium glutamate prevented the development of cisplatin-induced neuropathy and partially improved intestinal transit after the fifth cisplatin administration with little impact on gastric dysmotility. MSG did not improve the histological damage of gut wall, but prevented the changes induced by cisplatin in the colonic myenteric plexus. CONCLUSION AND INFERENCES: Our results suggest that MSG can improve some dysfunctions caused by anticancer chemotherapy in the gut and other systems, associated, at least partially, with neuroprotectant effects. The potentially useful adjuvant role of this food additive to reduce chemotherapy-induced sequelae warrants further evaluation.

Mast Cell Regulation and Irritable Bowel Syndrome: Effects of Food Components with Potential Nutraceutical Use.

Mast cells are key actors in inflammatory reactions. Upon activation, they release histamine, heparin and nerve growth factor, among many other mediators that modulate immune response and neuron sensitization. One important feature of mast cells is that their population is usually increased in animal models and biopsies from patients with irritable bowel syndrome (IBS). Therefore, mast cells and mast cell mediators are regarded as key components in IBS pathophysiology. IBS is a common functional gastrointestinal disorder affecting the quality of life of up to 20% of the population worldwide. It is characterized by abdominal pain and altered bowel habits, with heterogeneous phenotypes ranging from constipation to diarrhea, with a mixed subtype and even an unclassified form. Nutrient intake is one of the triggering factors of IBS. In this respect, certain components of the daily food, such as fatty acids, amino acids or plant-derived substances like flavonoids, have been described to modulate mast cells' activity. In this review, we will focus on the effect of these molecules, either stimulatory or inhibitory, on mast cell degranulation, looking for a nutraceutical capable of decreasing IBS symptoms.

Effects of Coffee and Its Components on the Gastrointestinal Tract and the Brain-Gut Axis.

Coffee is one of the most popular beverages consumed worldwide. Roasted coffee is a complex mixture of thousands of bioactive compounds, and some of them have numerous potential health-promoting properties that have been extensively studied in the cardiovascular and central nervous systems, with relatively much less attention given to other body systems, such as the gastrointestinal tract and its particular connection with the brain, known as the brain-gut axis. This narrative review provides an overview of the effect of coffee brew; its by-products; and its components on the gastrointestinal mucosa (mainly involved in permeability, secretion, and proliferation), the neural and non-neural components of the gut wall responsible for its motor function, and the brain-gut axis. Despite in vitro, in vivo, and epidemiological studies having shown that coffee may exert multiple effects on the digestive tract, including antioxidant, anti-inflammatory, and antiproliferative effects on the mucosa, and pro-motility effects on the external muscle layers, much is still surprisingly unknown. Further studies are needed to understand the mechanisms of action of certain health-promoting properties of coffee on the gastrointestinal tract and to transfer this knowledge to the industry to develop functional foods to improve the gastrointestinal and brain-gut axis health.

Co-treatment With BGP-15 Exacerbates 5-Fluorouracil-Induced Gastrointestinal Dysfunction.

Gastrointestinal (GI) side-effects of chemotherapy present a constant impediment to efficient and tolerable treatment of cancer. GI symptoms often lead to dose reduction, delays and cessation of treatment. Chemotherapy-induced nausea, bloating, vomiting, constipation, and/or diarrhea can persist up to 10 years post-treatment. We have previously reported that long-term 5-fluorouracil (5-FU) administration results in enteric neuronal loss, acute inflammation and intestinal dysfunction. In this study, we investigated whether the cytoprotectant, BGP-15, has a neuroprotective effect during 5-FU treatment. Balb/c mice received tri-weekly intraperitoneal 5-FU (23 mg/kg/d) administration with and without BGP-15 (15 mg/kg/d) for up to 14 days. GI transit was analyzed via in vivo serial X-ray imaging prior to and following 3, 7, and 14 days of treatment. On day 14, colons were collected for assessment of ex vivo colonic motility, neuronal mitochondrial superoxide, and cytochrome c levels as well as immunohistochemical analysis of myenteric neurons. BGP-15 did not inhibit 5-FU-induced neuronal loss, but significantly increased the number and proportion of choline acetyltransferase (ChAT)-immunoreactive (IR) and neuronal nitric oxide synthase (nNOS)-IR neurons in the myenteric plexus. BGP-15 co-administration significantly increased mitochondrial superoxide production, mitochondrial depolarization and cytochrome c release in myenteric plexus and exacerbated 5-FU-induced colonic inflammation. BGP-15 exacerbated 5-FU-induced colonic dysmotility by reducing the number and proportion of colonic migrating motor complexes and increasing the number and proportion of fragmented contractions and increased fecal water content indicative of diarrhea. Taken together, BGP-15 co-treatment aggravates 5-FU-induced GI side-effects, in contrast with our previous findings that BGP-15 alleviates GI side-effects of oxaliplatin.

May a sigma-1 antagonist improve neuropathic signs induced by cisplatin and vincristine in rats?

BACKGROUND: The antineoplastic drugs cisplatin and vincristine induce peripheral neuropathies. The sigma-1 receptor (σ1R) is expressed in areas of pain control, and its blockade with the novel selective antagonist MR-309 has shown efficacy in nociceptive and neuropathic pain models. Our goal was to test whether this compound reduces neuropathic signs provoked by these antitumoural drugs. METHODS: Rats were treated with cisplatin or vincristine to induce neuropathies. The effects of acute or repeated administration of MR-309 were tested on mechanical and thermal sensitivity, electrophysiological activity of Aδ-primary afferents in the rat skin-saphenous nerve preparation, and gastrointestinal or cardiovascular functions. RESULTS: Rats treated with antitumourals developed tactile allodynia, while those treated with vincristine also developed mechanical hyperalgesia. These in vivo modifications correlated with electrophysiological hyperactivity (increased spontaneous activity and hyperresponsiveness to innocuous and noxious mechanical stimulation). Animals treated with cisplatin showed gastrointestinal impairment and those receiving vincristine showed cardiovascular toxicity. A single dose of MR-309 strongly reduced both nociceptive behaviour and electrophysiological changes. Moreover, its concomitant administration with the antitumourals blocked the development of neuropathic symptoms, thus restoring mechanical sensitivity, improving the impairment of feeding behaviour and gastrointestinal transit in the cisplatin-treated group along with ameliorating the altered vascular reactivity recorded in rats treated with vincristine. CONCLUSION: σ1R antagonist, MR-309, reduces sensorial and electrophysiological neuropathic signs in rats treated with cisplatin or vincristine and, in addition, reduces gastrointestinal and cardiovascular side effects. SIGNIFICANCE: σ1R antagonism could be an interesting and new option to palliate antitumoural neuropathies.

Alterations of colonic sensitivity and gastric dysmotility after acute cisplatin and granisetron.

BACKGROUND: Cisplatin is a highly emetogenic antineoplastic drug and induces peripheral neuropathy when given in cycles. Granisetron, a 5-HT3 antagonist, is clinically used to prevent chemotherapy-induced nausea/emesis and abdominal pain in irritable bowel syndrome. The effects of cisplatin on visceral sensitivity and those of granisetron in the context of cancer chemotherapy are not well known. METHODS: Adult male Wistar rats received two intraperitoneal injections 30 minutes apart: granisetron (1 mg kg-1 )/vehicle and cisplatin (6 mg kg-1 )/vehicle. Thereafter, nausea-like behavior was measured as bedding intake for 4 hours, and gastric dysmotility was measured radiographically for 8 hours. Gastric weight and size were determined ex vivo and samples of the forestomach, corpus, ileum, and colon were obtained for histological analysis at 4 and 30 hours after cisplatin/vehicle. Visceral sensitivity was measured as abdominal contractions in response to mechanical intracolonic stimulation 2 hours after cisplatin/vehicle. KEY RESULTS: Cisplatin-induced bedding intake and gastric dysmotility, and granisetron blocked these effects, which occurred in the absence of frank mucositis. Visceral sensitivity was reduced to a similar extent by both drugs alone or in combination. CONCLUSIONS AND INFERENCES: Cisplatin-induced bedding intake and gastric dysmotility were blocked by granisetron, confirming the involvement of serotonin acting on 5-HT3 receptors. Unexpectedly, visceral sensitivity to colonic distension was reduced, to the same extent, by cisplatin, granisetron, and their combination, suggesting important mechanistic differences with nausea and gastric dysmotility that warrant further investigation.

Oxaliplatin-induced enteric neuronal loss and intestinal dysfunction is prevented by co-treatment with BGP-15.

BACKGROUND AND PURPOSE: Gastrointestinal side effects of chemotherapy are an under-recognized clinical problem, leading to dose reduction, delays and cessation of treatment, presenting a constant challenge for efficient and tolerated anti-cancer treatment. We have found that oxaliplatin treatment results in intestinal dysfunction, oxidative stress and loss of enteric neurons. BGP-15 is a novel cytoprotective compound with potential HSP72 co-inducing and PARP inhibiting properties. In this study, we investigated the potential of BGP-15 to alleviate oxaliplatin-induced enteric neuropathy and intestinal dysfunction. EXPERIMENTAL APPROACH: Balb/c mice received oxaliplatin (3 mg·kg-1 ·day-1 ) with and without BGP-15 (15 mg·kg-1 ·day-1 : i.p.) tri-weekly for 14 days. Gastrointestinal transit was analysed via in vivo X-ray imaging, before and after treatment. Colons were collected to assess ex vivo motility, neuronal mitochondrial superoxide and cytochrome c levels and for immunohistochemical analysis of myenteric neurons. KEY RESULTS: Oxaliplatin-induced neuronal loss increased the proportion of neuronal NO synthase-immunoreactive neurons and increased levels of mitochondrial superoxide and cytochrome c in the myenteric plexus. These changes were correlated with an increase in PARP-2 immunoreactivity in the colonic mucosa and were attenuated by BGP-15 co-treatment. Significant delays in gastrointestinal transit, intestinal emptying and pellet formation, impaired colonic motor activity, reduced faecal water content and lack of weight gain associated with oxaliplatin treatment were restored to sham levels in mice co-treated with BGP-15. CONCLUSION AND IMPLICATIONS: Our results showed that BGP-15 ameliorated oxidative stress, increased enteric neuronal survival and alleviated oxaliplatin-induced intestinal dysfunction, suggesting that BGP-15 may relieve the gastrointestinal side effects of chemotherapy.

Guanylate Cyclase C: A Current Hot Target, from Physiology to Pathology.

BACKGROUND: Guanylate cyclase C (GC-C) receptor is a transmembrane receptor, predominantly expressed in intestinal epithelial cells, which is considered to play a main role in homeostasis and function of the digestive tract. The endogenous ligands for this receptor are the paracrine hormones uroguanylin and guanylin. Upon ligand binding, GC-C receptors increase cyclic guanosine monophosphate (cGMP) levels, regulating a variety of key cell-type specific processes such as chloride and bicarbonate secretion, epithelial cell growth, regulation of intestinal barrier integrity and visceral sensitivity. It has been suggested that GC-C acts as an intestinal tumor suppressor with the potential to prevent the initiation and progression of colorectal cancer. In fact, loss of ligand expression is a universal step in sporadic colorectal carcinogenesis. Interestingly, the role of GC-C is not limited to the digestive tract but it has been extended to several other systems such as the cardiovascular system, kidney, and the central nervous system, where it has been involved in a gut-hypothalamus endocrine axis regulating appetite. Objetive: In this review we summarize the physiology of the GC-C receptor and its ligands, focusing on newly developed drugs like linaclotide, and their suggested role to reverse/prevent the diseases in which the receptor is involved. CONCLUSION: Available data points toward a relationship between uroguanylin and guanylin and their receptor and pathological processes like gastrointestinal and renal disorders, colorectal cancer, obesity, metabolic syndrome and mental disorders among others. Recent pharmacological developments in the regulation of GC-receptor may involve further improvements in the treatment of relevant diseases.

Irinotecan-Induced Gastrointestinal Dysfunction Is Associated with Enteric Neuropathy, but Increased Numbers of Cholinergic Myenteric Neurons.

Gastrointestinal dysfunction is a common side-effect of chemotherapy leading to dose reductions and treatment delays. These side-effects may persist up to 10 years post-treatment. A topoisomerase I inhibitor, irinotecan (IRI), commonly used for the treatment of colorectal cancer, is associated with severe acute and delayed-onset diarrhea. The long-term effects of IRI may be due to damage to enteric neurons innervating the gastrointestinal tract and controlling its functions. Balb/c mice received intraperitoneal injections of IRI (30 mg/kg-1) 3 times a week for 14 days, sham-treated mice received sterile water (vehicle) injections. In vivo analysis of gastrointestinal transit via serial x-ray imaging, facal water content, assessment of gross morphological damage and immunohistochemical analysis of myenteric neurons were performed at 3, 7 and 14 days following the first injection and at 7 days post-treatment. Ex vivo colonic motility was analyzed at 14 days following the first injection and 7 days post-treatment. Mucosal damage and inflammation were found following both short and long-term treatment with IRI. IRI-induced neuronal loss and increases in the number and proportion of ChAT-IR neurons and the density of VAChT-IR fibers were associated with changes in colonic motility, gastrointestinal transit and fecal water content. These changes persisted in post-treatment mice. Taken together this work has demonstrated for the first time that IRI-induced inflammation, neuronal loss and altered cholinergic expression is associated with the development of IRI-induced long-term gastrointestinal dysfunction and diarrhea.

Characterization of Cardiovascular Alterations Induced by Different Chronic Cisplatin Treatments.

In the last years, many clinical studies have revealed that some cisplatin-treated cancer survivors have a significantly increased risk of cardiovascular events, being cisplatin-induced cardiovascular toxicity an increasing concern. The aim of the present work was to evaluate the cardiovascular alterations induced by different chronic cisplatin treatments, and to identify some of the mechanisms involved. Direct blood pressure, basal cardiac (left ventricle and coronary arteries) and vascular (aortic and mesenteric) functions were evaluated in chronic (5 weeks) saline- or cisplatin-treated male Wistar rats. Three different doses of cisplatin were tested (1, 2, and 3 mg/kg/week). Alterations in cardiac and vascular tissues were also investigated by immunohistochemistry, Western Blot, and or quantitative RT-PCR analysis. Cisplatin treatment provoked a significant modification of arterial blood pressure, heart rate, and basal cardiac function at the maximum dose tested. However, vascular endothelial dysfunction occurred at lower doses. The expression of collagen fibers and conexin-43 were increased in cardiac tissue in cisplatin-treated rats with doses of 2 and 3 mg/kg/week. The expression of endothelial nitric oxide synthase was also modified in cardiac and vascular tissues after cisplatin treatment. In conclusion, chronic cisplatin treatment provokes cardiac and vascular toxicity in a dose-dependent manner. Besides, vascular endothelial dysfunction occurs at lower doses than cardiac and systemic cardiovascular toxicity. Moreover, some structural changes in cardiac and vascular tissues are also patent even before any systemic cardiovascular alterations.