Expression enhancement in brown adipose tissue of genes related to thermogenesis and mitochondrial dynamics after administration of pepsin egg white hydrolysate.

Nutritional compounds could be a safe and less expensive treatment for complications associated with obesity and metabolic syndrome (MetS). The aim of this study was to investigate the mechanism of action and the target tissues of a pepsin egg white hydrolysate (EWH) which had previously been demonstrated to improve some obesity-related disorders on a high-fat/high-glucose rat model. Wistar rats were used and divided into 3 groups: Control group (C), High-fat/high-glucose diet (MS) and high-fat/high-glucose diet + EWH (MSH). The rats were fed for 20 weeks and the EWH was administered from the 9th week. At the end of the study, white adipose tissue (WAT), brown adipose tissue (BAT) and muscle samples were collected for RT-qPCR analyses and immunohistochemistry. Our results showed a gene expression enhancement (2-fold basal level) in BAT of genes related to thermogenesis and mitochondrial dynamics. Mitochondrial DNA quantification and immunohistochemistry results also showed an increase of the mitochondrial content in this tissue. In conclusion, our results show the potential metabolic effect of this pepsin EWH by enhancing mitochondrial proliferation and gene expression related to thermogenesis in BAT. The EWH could be used as a functional food ingredient which is able to increase energy expenditure and counteract obesity-related MetS in a chronically obese society.

Cannabinoid pharmacology and therapy in gut disorders.

Cannabis sp. and their products (marijuana, hashish…), in addition to their recreational, industrial and other uses, have a long history for their use as a remedy for symptoms related with gastrointestinal diseases. After many reports suggesting these beneficial effects, it was not surprising to discover that the gastrointestinal tract expresses endogenous cannabinoids, their receptors, and enzymes for their synthesis and degradation, comprising the so-called endocannabinoid system. This system participates in the control of tissue homeostasis and important intestinal functions like motor and sensory activity, nausea, emesis, the maintenance of the epithelial barrier integrity, and the correct cellular microenvironment. Thus, different cannabinoid-related pharmacological agents may be useful to treat the main digestive pathologies. To name a few examples, in irritable bowel syndrome they may normalize dysmotility and reduce pain, in inflammatory bowel disease they may decrease inflammation, and in colorectal cancer, apart from alleviating some symptoms, they may play a role in the regulation of the cell niche. This review summarizes the main recent findings on the role of cannabinoid receptors, their synthetic or natural ligands and their metabolizing enzymes in normal gastrointestinal function and in disorders including irritable bowel syndrome, inflammatory bowel disease, colon cancer and gastrointestinal chemotherapy-induced adverse effects (nausea/vomiting, constipation, diarrhea).

Preclinical evaluation of the effects on the gastrointestinal tract of the antineoplastic drug vincristine repeatedly administered to rats.

BACKGROUND: Vincristine is a commonly used chemotherapeutic agent. It is associated with undesirable digestive side effects. However, the impact of vincristine on gastrointestinal structure and motility or its long-term effects have not been deeply studied in animal models. This could be useful in order to develop therapeutic or preventive strategies for cancer patients. The aim of this study was to analyze such effects. METHODS: Rats received saline or vincristine (0.1 mg kg-1 , ip) daily for 10 days. Evaluations were performed during treatment and 2-6 weeks after. Somatic mechano-sensitivity was assessed using von Frey hairs. Gastrointestinal motor function was studied by means of radiographic still images and colonic propulsion of fecal pellets using fluoroscopy videos. Histological assessment of the gut morphology and immunohistochemistry for HuC/D and nNOS were performed in whole-mount myenteric plexus preparations. KEY RESULTS: Peripheral sensitivity was increased in animals treated with vincristine and did not subside 2 weeks after treatment finalization. Vincristine treatment inhibited gastrointestinal motility although this was recovered to normal values with time. Damage in the digestive wall after vincristine treatment was greater in the ileum than in the colon. Villi shortening (in ileum) and large inflammatory nodules still remained 2 weeks after treatment finalization. Finally, the proportion of nNOS-immunoreactive neurons was increased with vincristine and continued to be increased 2 weeks after treatment finalization. CONCLUSIONS AND INFERENCES: Vincristine alters gastrointestinal motility, peripheral sensitivity and mucosal architecture. Vincristine-induced neuropathy (somatic and enteric), intestinal mucosa damage and inflammatory infiltrations are relatively long-lasting.

Pepsin egg white hydrolysate ameliorates metabolic syndrome in high-fat/high-dextrose fed rats.

The aim of this study was to examine the effect of a pepsin egg white hydrolysate (EWH) on metabolic complications using a high-fat/high-dextrose diet-induced Metabolic Syndrome (MetS) experimental model. Male Wistar rats were divided into 4 groups which received: standard diet and water (C), standard diet and a solution with 1 g kg-1 day-1 of EWH (CH), high-fat/high-dextrose diet and water (MS), and high-fat/high-dextrose diet and a solution with 1 g kg-1 day-1 of EWH (MSH). EWH consumption normalized body weight gain; abdominal obesity and peripheral neuropathy developed in MetS animals, and adipose tissue and liver weight, as well as plasma glucose were reduced. Oxidative stress and inflammation biomarkers were normalized in MSH animals. In conclusion, the oral administration of EWH could be used as a functional food ingredient to improve some complications associated with MetS induced by unhealthy diets.

Alterations in the small intestinal wall and motor function after repeated cisplatin in rat.

BACKGROUND: Gastrointestinal adverse effects occurring during cancer chemotherapy are well known and feared; those persisting once treatment has finished are relatively unknown. We characterized the alterations occurring in the rat small intestine, after repeated treatment with cisplatin. METHODS: Male Wistar rats received saline or cisplatin (2 mg kg-1  week-1 , for 5 weeks, ip). Gastric motor function was studied non-invasively throughout treatment (W1-W5) and 1 week after treatment finalization (W6). During W6, upper gastrointestinal motility was also invasively studied and small intestinal samples were collected for histopathological and molecular studies. Structural alterations in the small intestinal wall, mucosa, submucosa, muscle layers, and lymphocytic nodules were histologically studied. Periodic acid-Schiff staining and immunohistochemistry for Ki-67, chromogranin A, and neuronal-specific enolase were used to detect secretory, proliferating, endocrine and neural cells, respectively. The expression of different markers in the tunica muscularis was analyzed by RT/qPCR. KEY RESULTS: Repeated cisplatin induced motility alterations during and after treatment. After treatment (W6), the small intestinal wall showed histopathological alterations in most parameters measured, including a reduction in the thickness of circular and longitudinal muscle layers. Expression of c-KIT (for interstitial cells of Cajal), nNOS (for inhibitory motor neurons), pChAT, and cChAT (for excitatory motor neurons) increased significantly (although both ChATs to a lesser extent). CONCLUSIONS & INFERENCES: Repeated cisplatin induces relatively long-lasting gut dysmotility in rat associated with important histopathological and molecular alterations in the small intestinal wall. In cancer survivors, the possible chemotherapy-induced histopathological, molecular, and functional intestinal sequelae should be evaluated.

May cannabinoids prevent the development of chemotherapy-induced diarrhea and intestinal mucositis? Experimental study in the rat.

BACKGROUND: The antineoplastic drug 5-fluoruracil (5-FU) is a pirimidine analog, which frequently induces potentially fatal diarrhea and mucositis. Cannabinoids reduce gastrointestinal motility and secretion and might prevent 5-FU-induced gut adverse effects. Here, we asked whether cannabinoids may prevent diarrhea and mucositis induced by 5-FU in the rat. METHODS: Male Wistar rats received vehicle or the non-selective cannabinoid agonist WIN 55,212-2 (WIN; 0.5 mg kg-1 injection-1 , 1 injection day-1 , 4 consecutive days) by intraperitoneal (ip) route; on the first 2 days, animals received also saline or 5-FU (150 mg kg-1 injection-1 , cumulative dose of 300 mg kg-1 ). Gastrointestinal motor function was radiographically studied after barium contrast intragastric administration on experimental days 1 and 4. Structural alterations of the stomach, small intestine and colon were histologically studied on day 4. PAS staining and immunohistochemistry for Ki67, chromogranin A and CD163 were used to detect secretory, proliferating, and endocrine cells, and activated macrophages respectively. KEY RESULTS: As shown radiographically, 5-FU induced significant gastric emptying delay (on days 1 and 4) and diarrhea (on day 4). WIN did not significantly alter the motility curves obtained for either control or 5-FU-treated animals but tended to reduce the severity of 5-FU-induced diarrhea and increased permanence of barium from day 1 to the beginning of day 4 in 5-FU-treated animals. 5-FU-induced mucositis was severe and not counteracted by WIN. CONCLUSIONS AND INFERENCES: 5-FU-induced diarrhea, but not mucositis, was partly prevented by WIN at a low dose. Cannabinoids might be useful to prevent chemotherapy-induced diarrhea.

Pepsin Egg White Hydrolysate Ameliorates Obesity-Related Oxidative Stress, Inflammation and Steatosis in Zucker Fatty Rats.

The aim of this work was to evaluate the effect of the administration of egg white hydrolysates on obesity-related disorders, with a focus on lipid metabolism, inflammation and oxidative stress, in Zucker fatty rats. Obese Zucker rats received water, pepsin egg white hydrolysate (750 mg/kg/day) or Rhizopus aminopeptidase egg white hydrolysate (750 mg/kg/day) for 12 weeks. Lean Zucker rats received water. Body weight, solid and liquid intakes were weekly measured. At the end of the study, urine, faeces, different organs and blood samples were collected. The consumption of egg white hydrolysed with pepsin significantly decreased the epididymal adipose tissue, improved hepatic steatosis, and lowered plasmatic concentration of free fatty acids in the obese animals. It also decreased plasma levels of tumor necrosis factor-alpha and reduced oxidative stress. Pepsin egg white hydrolysate could be used as a tool to improve obesity-related complications.

Suppression of spermatogenesis for cell transplantation in adult mice.

Spermatogenesis occurs within the testis of adult males by a complex and very well organized process. Breakthroughs in techniques such as cryopreservation and culture of spermatogenic cells and the maturation of these cells in exogenous testes after transplantation renewed the interest in this process. Transplantation of spermatogenic cells from a donor to a recipient animal needs a preparatory step that consists in the elimination of the endogenous population of spermatogenic cells. The most common method used to empty the seminiferous tubules is the treatment with busulfan (1,4-butanediol dimethanesulfonate). Busulfan partially eliminates stem cells because of its alkylating nature, but a residual component of stem cells survives the treatment and competes in the regeneration of the testis with transplanted cells. Estradiol has also been used as an agent that causes a delay in the process of spermatogenesis by altering its hormonal stimulation, although it does not affect the spermatogonia population. Therefore, we have tested different treatments with busulfan, estradiol benzoate, and also an agonist of the chorionic gonadotrophin-releasing hormone, leuprolide acetate, for the inhibition of endogenous spermatogenesis. We have found that a combination of estradiol, busulfan, and leuprolide can destroy the population of endogenous spermatogenic cells without altering Sertoli cells and maintains the optimal environment needed to allow the development of transplanted cells.

Cell proliferation is reduced in parthenogenetic mouse embryos at the blastocyst stage: a quantitative study.

BACKGROUND: Parthenogenetic and androgenetic embryos fail to develop to term, possibly because of genomic imprinting, an epigenetic alteration of certain genes, depending on the parent of origin. The effect of this phenomenon has been studied mainly in mid-gestation embryos, without morphological abnormalities detected during the preim-plantation period. Nevertheless, parthenogenetic mouse embryos never develop to the blastocyst stage in the same numbers as do fertilized ones, and up to 50% fail to implant, suggesting that genomic imprinting may be responsible for this lack of viability. METHODS: We have made a quantitative and morphometric analysis of the cell proliferation capacity at the end of the preimplantation period in parthenogenetic mice to study if such parameter is affected by the monoparental constitution of the embryos. RESULTS AND CONCLUSIONS: We have found that, apart from the different morphology and cell number induced by culture conditions, parthenogenetic mouse blastocysts have a significantly smaller cell number than do fertilized control embryos. Our interpretation of these results is that the monoparental constitution of these embryos may be responsible for the lack of some factor required to sustain cell proliferation after the morula stage.

Comparative analysis of in vitro development of outbred mouse embryos cultured in Krebs-Ringer or tyrode-derived media.

Culture media for mouse preimplantation development are usually derived from two basic solutions: Krebs-Ringer and Tyrode. We have used outbred mice (OF1) to make a comparative analysis of derived media of both types and their success in sustaining development from the one-cell to the blastocyst stage. The best results (up to 50%), in terms of overcoming the two-cell block and sustaining development to expanded blastocyst, were obtained with media derived from Tyrode's solution and with Krebs-Ringer-based media in which the high concentrations of certain metabolites (Cl-, K+, Mg2+ and PO(4)3+) were reduced to the values present in the Tyrode-derived media. Interestingly, medium T6 (based on Tyrode and incapable of avoiding developmental block on its own), yielded the best development rate with the addition of ethylenediaminetetraacetic acid (EDTA). The addition of glutamine to medium T6 did not have any effect. We further developed T7, a medium based on T6 but incorporating the concentrations of nutrients present in the oviduct. This medium also proved better than its Krebs-Ringer counterpart (MTF), but not better than T6, probably due to the different nutritive requirements in the transition from morula to blastocyst. The two most significant findings were: i) that Tyrode-based formulations were superior to media based on Krebs-Ringer solution, and ii) that medium T6 with EDTA was as effective for mouse egg culture as the recently developed KSOM medium.

Parthenogenetic activation of mouse oocytes using calcium ionophores and protein kinase C stimulators.

Fertilization involves the production of inositol trisphosphate and diacylglycerol with a subsequent increase in intracellular calcium concentration ([Ca2+]i) and the activation of a calcium-dependent protein kinase, the so-called protein kinase C (PKC). Methods of parthenogenetic activation have focused on this calcium wave which seems to be large enough to generate all the responses associated with fertilization and even finally inducing the activation of PKC activity. The specific stimulation of PKC by phorbol esters in turn elicits [Ca2+]i oscillations although no reports exist claiming that the mere activation of this protein is capable of sustaining embryonic development. In this paper we describe the effect of different calcium ionophores and phorbol esters as parthenogenetic agents on mouse oocytes compared with ethanol as the standard procedure. Phorbol esters (OAG) fail to activate a significant number of oocytes, with very few reaching blastocyst stage. However, when a calcium ionophore (A23187) is added, the percentage of embryos reaching the blastocyst stage increases to such an extent that it is the best chemical method assayed to date. We conclude that incubation with both compounds combined inhibits feed-back processes between the above reactions and so induces a more physiologic parthenogenetic activation.

ENDO A cytokeratin expression in the inner cell mass of parthenogenetic mouse embryos.

During the preimplantation period of development, the first cellular polarization and diversification of the mouse embryo occurs. This process starts at the eight-cell stage and is directly driven by the cytoskeleton. Cell polarization finally leads to the first embryonic epithelium, the trophectoderm, characterized by the presence of cytokeratins. It has not been described whether genomic imprinting, an epigenetic modification of certain genes depending on the parent-of-origin, affects preimplantation development. However, implantation is one of the steps in which an exceptionally high mortality rate is observed in mouse parthenogenetic embryos, a phenomenon that may be influenced by a deficiency in trophectoderm differentiation. To assess this possibility we analyzed the expression of various cytoskeletal proteins in late preimplanted embryos. No differences were observed in the expression of microtubules and microfilaments, but surprisingly, the undifferentiated cells of the parthenogenetic inner cell mass showed distinct cytokeratin staining. This anomalous cytoskeleton expression may be considered as one of the earliest manifestation described to date of the effect of genomic imprinting in development.

Light microscopic catalase histochemistry in mussel digestive gland tissue.

Different light microscopical procedures for the histochemical demonstration of catalase were tested in cryostat sections of mussel digestive gland tissue by using both benzidine and diaminobenzidine (DAB) as hydrogen donors. The selected procedure, which was also applied to mouse liver for comparative purposes, consisted of incubation in media containing 0.2% DAB and 0.3% H2O2 at pH 10.4 for 35 min at 42 degrees C. Addition of 0.01 M imidazole to the incubation medium increased the staining intensity of the histochemical procedure. The positive reaction product was localized in epithelial cells lining the digestive tubules and the ducts. The histochemical reaction was inhibited partially by aminotriazole or sodium azide and disappeared completely by omission of H2O2 from the incubation medium. On the other hand, heat resistant non-enzymatic reactions were observed in sites known to contain lipofuscins such as epithelial cells of the gastrointestinal tract and connective tissue brown cells.