From the Gut to the Brain: The Role of Enteric Glial Cells and Their Involvement in the Pathogenesis of Parkinson's Disease.

The brain-gut axis has been identified as an important contributor to the physiopathology of Parkinson's disease. In this pathology, inflammation is thought to be driven by the damage caused by aggregation of α-synuclein in the brain. Interestingly, the Braak's theory proposes that α-synuclein misfolding may originate in the gut and spread in a "prion-like" manner through the vagus nerve into the central nervous system. In the enteric nervous system, enteric glial cells are the most abundant cellular component. Several studies have evaluated their role in Parkinson's disease. Using samples obtained from patients, cell cultures, or animal models, the studies with specific antibodies to label enteric glial cells (GFAP, Sox-10, and S100ß) seem to indicate that activation and reactive gliosis are associated to the neurodegeneration produced by Parkinson's disease in the enteric nervous system. Of interest, Toll-like receptors, which are expressed on enteric glial cells, participate in the triggering of immune/inflammatory responses, in the maintenance of intestinal barrier integrity and in the configuration of gut microbiota; thus, these receptors might contribute to Parkinson's disease. External factors like stress also seem to be relevant in its pathogenesis. Some authors have studied ways to reverse changes in EGCs with interventions such as administration of Tryptophan-2,3-dioxygenase inhibitors, nutraceuticals, or physical exercise. Some researchers point out that beyond being activated during the disease, enteric glial cells may contribute to the development of synucleinopathies. Thus, it is still necessary to further study these cells and their role in Parkinson's disease.

Effects of vincristine and monosodium glutamate on gastrointestinal motility and visceral sensitivity.

BACKGROUND: Chemotherapy-induced adverse effects are an unresolved nightmare. In preclinical studies in rats, the food additive monosodium glutamate (MSG) improved some of the side effects caused by cisplatin, but its effects in other models of chemotherapy-treated animals are not well known. The aim of this study was to test if MSG may improve some of the adverse effects induced by vincristine in rats. METHODS: Young male Wistar rats were exposed or not to MSG (4 g L-1 ) in drinking water from week 0 till 1 week after treatment (week 3). Rats received two cycles of five daily intraperitoneal (ip) injections (Monday to Friday, weeks 1 and 2) of either saline (2 mL kg-1 ) or vincristine (0.1 mg kg-1 ). Gastrointestinal motility was measured in vivo by radiological methods after the first and tenth ip administrations. On week 3, the threshold for mechanical somatic and colorectal sensitivity was recorded using Von Frey filaments applied to the paws and an intracolonic balloon, respectively. Finally, samples of the terminal ileum and distal colon were histologically evaluated in sections. KEY RESULTS: Vincristine reduced body weight gain, food intake, and upper gastrointestinal transit, caused somatic (but not visceral) hypersensitivity and increased the thickness of the submucosal and muscle layers of the small intestine. In vincristine-treated animals, MSG partially prevented gastrointestinal dysmotility and reduced visceral sensitivity but did not improve structural alterations of the small intestine. CONCLUSIONS & INFERENCES: MSG could be used as an adjuvant to conventional treatments to improve some gastrointestinal dysfunctions caused by chemotherapy.

Effectiveness and safety of non-invasive ventilation in the management of cardiogenic shock.

INTRODUCTION AND OBJECTIVES: Cardiogenic shock (CS) has long been considered a contraindication for the use of non-invasive ventilation (NIV). The main objective of this study was to analyze the effectiveness, measured as NIV success, in patients with respiratory failure due to CS. As secondary objective, we studied risk factors for NIV failure and compared the outcome of patients treated with NIV versus invasive mechanical ventilation (IMV). METHODS: Retrospective study on a prospective database, over a period of 25 years, of all consecutively patients admitted to an intensive care unit, with a diagnosis of CS and treated with NIV. A comparison was made between patients on NIV and patients on IMV using propensity score matching analysis. RESULTS: Three hundred patients were included, mean age 73.8 years, mean SAPS II 49. The main cause of CS was acute myocardial infarction (AMI): 164 (54.7%). NIV failure occurred in 153 (51%) cases. Independent factors for NIV failure included D/E stages of CS, AMI, NIV related complications, and being transferred from the ward. In the propensity analysis, hospital mortality (OR 1.69, 95% CI 1.09-2.63) and 1 year mortality (OR 1.61, 95% CI 1.04-2.51) was higher in IMV. Mortality was lower with NIV (vs. EIT-IMV) in C stage (10.1% vs. 32.9%; p<0.001) but did not differ in D stage or E stage. CONCLUSIONS: NIV seems to be relatively effective and safe in the treatment of early-stage CS.

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.

Radiographic and histopathological study of gastrointestinal dysmotility in lipopolysaccharide-induced sepsis in the rat.

BACKGROUND: Sepsis is a highly incident condition in which a cascade of proinflammatory cytokines is involved. One of its most frequent consequences is ileus, which can increase mortality. Animal models such as that induced by systemic administration of lipopolysaccharide (LPS) are useful to deeply evaluate this condition. The effects of sepsis on the gastrointestinal (GI) tract have been explored but, to our knowledge, in vivo studies showing the motor and histopathological consequences of endotoxemia in an integrated way are lacking. Our aim was to study in rats the effects of sepsis on GI motility, using radiographic methods, and to assess histological damage in several organs. METHODS: Male rats were intraperitoneally injected with saline or E. coli LPS at 0.1, 1, or 5 mg kg-1 . Barium sulfate was intragastrically administered, and X-rays were performed 0-24 h afterwards. Several organs were collected for organography, histopathology, and immunohistochemistry studies. KEY RESULTS: All LPS doses caused gastroparesia, whereas changes in intestinal motility were dose-and time-dependent, with an initial phase of hypermotility followed by paralytic ileus. Lung, liver, stomach, ileum, and colon (but not spleen or kidneys) were damaged, and density of neutrophils and activated M2 macrophages and expression of cyclooxygenase 2 were increased in the colon 24 h after LPS 5 mg kg-1 . CONCLUSIONS AND INFERENCES: Using radiographic, noninvasive methods for the first time, we show that systemic LPS causes dose-, time-, and organ-dependent GI motor effects. Sepsis-induced GI dysmotility is a complex condition whose management needs to take its time-dependent changes into account.

Radiographic assessment of the impact of sex and the circadian rhythm-dependent behaviour on gastrointestinal transit in the rat.

Relatively little is known about the influence of sex and the circadian rhythm on gastrointestinal transit. However, these factors could have an important impact on aspects such as digestion, oral absorption of drugs or the clinical manifestation of gastrointestinal diseases, among others. Remarkably, preclinical models have scarcely taken these factors into consideration. In this study, we assessed the gastrointestinal transit of young adult Wistar Han rats of both sexes, under normal and inverted light cycle. To do this, serial radiographs were taken for 24 h (T0-T24) after intragastric barium administration and subsequently analysed to construct transit curves for each gastrointestinal region. Under a normal light cycle, transit curves were similar, except for a slower transit in females compared with males from T8 to T24. Under the inverted cycle, there was a significant acceleration in stomach emptying (similar in both sexes), emptying of the small intestine (even faster in females) and filling of the caecum and colon (which was also even faster in females). This study confirms, using X-ray non-invasive methods for the first time, that both sex and circadian rhythm (probably through its effect on behaviour) influence gastrointestinal transit in laboratory animals.

Analysis of combined non-invasive respiratory support in the first six waves of the COVID-19 pandemic. Outcome according to the first respiratory support.

Introduction: COVID-19 can lead to acute respiratory failure (ARF) requiring admission to intensive care unit (ICU). This study analyzes COVID-19 patients admitted to the ICU, according to the initial respiratory support. Its main aim is to determine if the use of combination therapy: high-flow oxygen system with nasal cannula (HFNC) and non-invasive ventilation (NIV), is effective and safe in the treatment of these patients. Methods: Retrospective observational study with a prospective database. All COVID-19 patients, admitted to the ICU, between March 11, 2020, and February 12, 2022, and who required HFNC, NIV, or endotracheal intubation with invasive mechanical ventilation (ETI-IMV) were analyzed. HFNC failure was defined as therapeutic escalation to NIV, and NIV failure as the need for ETI-IMV or death in the ICU. The management of patients with non-invasive respiratory support included the use of combined therapy with different devices. The study period included the first six waves of the pandemic in Spain. Results: 424 patients were analyzed, of whom 12 (2.8%) received HFNC, 397 (93.7%) NIV and 15 (3.5%) ETI-IMV as first respiratory support. PaO2/FiO2 was 145 ± 30, 119 ± 26 and 117 ± 29 mmHg, respectively (p = 0.003). HFNC failed in 11 patients (91.7%), who then received NIV. Of the 408 patients treated with NIV, 353 (86.5%) received combination therapy with HFNC. In patients treated with NIV, there were 114 failures (27.9%). Only the value of SAPS II index (p = 0.001) and PaO2/FiO2 (p < 0.001) differed between the six analyzed waves, being the most altered values in the 3rd and 6th waves. Hospital mortality was 18.7%, not differing between the different waves (p = 0.713). Conclusions: Severe COVID-19 ARF can be effectively and safely treated with NIV combined with HFNC. The clinical characteristics of the patients did not change between the different waves, only showing a slight increase in severity in the 3rd and 6th waves, with no difference in the outcome.

Evaluation of the Effects of Instant Cascara Beverage on the Brain-Gut Axis of Healthy Male and Female Rats.

Instant cascara (IC) is a sustainable beverage obtained from dried coffee cherry pulp, rich in nutrients and bioactive compounds. The present research aimed to determine the effects of IC on general health and brain-gut axis parameters of healthy female and male rats. Wistar rats were exposed to IC (10 mg/mL) in their drinking water for 3 weeks. Body weight and solid and liquid intakes were monitored as indicators of food safety. Gastrointestinal transit was radiographically evaluated one day (acute) and 3 weeks (chronic) after the start of IC exposure. Locomotor activity, anxiety, and anhedonia of the animals after 3 weeks of treatment was also studied. Overall, compared to water-exposed animals, IC significantly increased food intake in males (p < 0.0001) and liquid intake in females (p < 0.05) without changes in body weight in either case. IC did not significantly modify gastrointestinal motility parameters after its acute or repeated intake and did not cause any significant behavioral alterations in males or females (p > 0.05). In conclusion, repeated intake of IC at the studied concentration did not negatively affect brain-gut axis functions of healthy male and female rats. Anxiety behavior, diarrhea, constipation, abnormal weight modifications, or other typical effects of toxicity were not observed in animals treated with the new powdered beverage, suggesting its food safety under the studied conditions.

The Enteric Glia and Its Modulation by the Endocannabinoid System, a New Target for Cannabinoid-Based Nutraceuticals?

The enteric nervous system (ENS) is a part of the autonomic nervous system that intrinsically innervates the gastrointestinal (GI) tract. Whereas enteric neurons have been deeply studied, the enteric glial cells (EGCs) have received less attention. However, these are immune-competent cells that contribute to the maintenance of the GI tract homeostasis through supporting epithelial integrity, providing neuroprotection, and influencing the GI motor function and sensation. The endogenous cannabinoid system (ECS) includes endogenous classical cannabinoids (anandamide, 2-arachidonoylglycerol), cannabinoid-like ligands (oleoylethanolamide (OEA) and palmitoylethanolamide (PEA)), enzymes involved in their metabolism (FAAH, MAGL, COX-2) and classical (CB1 and CB2) and non-classical (TRPV1, GPR55, PPAR) receptors. The ECS participates in many processes crucial for the proper functioning of the GI tract, in which the EGCs are involved. Thus, the modulation of the EGCs through the ECS might be beneficial to treat some dysfunctions of the GI tract. This review explores the role of EGCs and ECS on the GI tract functions and dysfunctions, and the current knowledge about how EGCs may be modulated by the ECS components, as possible new targets for cannabinoids and cannabinoid-like molecules, particularly those with potential nutraceutical use.

Effects of Commercial Probiotics on Colonic Sensitivity after Acute Mucosal Irritation.

Gastrointestinal pathologies associated with abdominal pain, such as irritable bowel syndrome or inflammatory bowel disease, lack sufficiently effective treatments. In our study we have used a rat model of visceral pain (72 animals; n = 8-13 per experimental group) to analyze the consequences of intracolonic administration of the irritant acetic acid on visceral sensitivity, histology of the colonic wall, and inflammatory response. Moreover, we have studied the possible beneficial effects of a pretreatment with a commercial probiotic (Actimel®). Contrary to expectations, acetic acid application (7 cm proximal to the anus) decreased the nociceptive response to intracolonic mechanical stimulation, with a slight increase in the histological damage of colonic mucosa. The intensity of these changes depended on the concentration (4% or 0.6%) and the time of application (30 or 60 min). Pretreatment with probiotics (by daily gavage, for 1 week) normalized the values obtained in the visceral sensitivity test but revealed an increase in the number of macrophages. These results suggest a possible activation of inhibitory mechanisms early after colonic irritation, not previously described (which need further experimental confirmation), and the ability of probiotics to normalize the effects of acetic acid. In addition, pretreatment with probiotics has a direct effect on immune functions, stimulating macrophagic activity.

Nutraceuticals and peripheral glial cells: a possible link?

A nutraceutical is a food-derived molecule that provides medical or health benefits beyond its basic nutritional role, including the prevention and treatment of disease and its symptoms. In the peripheral nervous system, satellite glial cells are found in close relationship with neurons, mainly in peripheral sensory ganglia, but, compared with other glial cells, the relationship between these cells and nutraceuticals has received little attention. After describing satellite glial cells and their role and changes in physiology and pathology, we review the studies on the effects of nutraceuticals as modulators of their functions. Maybe due to the difficulties in selectively labeling these cells, only a few studies, performed mainly in rodent models, have analyzed nutraceutical effects, showing that N-acetylcysteine, curcumin, quercetin, osthole and resveratrol may palliate neuropathic pain through satellite glial cells-dependent pathways, namely antioxidant mechanisms and/or interference with purinergic signaling. Neither other conditions in which satellite glial cells are involved (visceral pain, nerve regeneration) nor other nutraceuticals or mechanisms of action have been studied. Although more preclinical and clinical research is needed, the available reports support the general notion that nutraceuticals may become interesting alternatives in the prevention and/or treatment of peripheral gliopathies and their associated conditions, including those affecting the satellite glial cells.

Is hypocapnia a risk factor for non-invasive ventilation failure in cardiogenic acute pulmonary edema?

INTRODUCTION AND PURPOSE: The impact of hypocapnia in the prognosis of cardiogenic acute pulmonary edema (CAPE) has not been sufficiently studied. The aim of this study was to analyse whether hypocapnia is a risk factor for non-invasive ventilation (NIV) failure and hospital mortality, in CAPE patients CAPE. METHODS: Retrospective observational study of all patients with CAPE treated with NIV. Patients were classified in three groups according to PaCO2 level (hypocapnic, eucapnic and hypercapnic). NIV failure was defined as the need for endotracheal intubation and/or death. RESULTS: 1138 patients were analysed, 390 (34.3%) of which had hypocapnia, 186 (16.3%) had normocapnia and 562 (49.4%) had hypercapnia. NIV failure was more frequent in hypocapnic (60 patients, 15.4%) than in eucapnic (16 pacientes, 8.6%) and hypercapnic group (562 pacientes, 10.7%), with statistical significance (p = 0.027), as well as hospital mortality, 73 (18.7%), 19(10.2%) and 83 (14.8%) respectively (p = 0.026). The predicted factors for NIV failure were the presence of do-not-intubate order, complications related to NIV, a lower left ventricular ejection fraction, higher SAPS II and SOFA score and a higher HACOR score at one hour of NIV initiation. CONCLUSIONS: Hypocapnia in patients with CAPE is associated with NIV failure and a greater in-hospital mortality.

The Isolated Mucosa of the Rat Colon Decellularization, Microscopy and Cell Cultures.

This project presents the most important findings of the studies, which we carried out in our laboratory on the decellularization of the rat isolated colonic mucosa. We have also included some details of the experiences gathered with the muscle layer as well as the whole wall of the colon. The question of the cytocompatibility of this new substrate has been addressed with the application of primary cultures of human cells and well-established cell lines. The possible applications in experimental and medical settings will be discussed.

Nutraceuticals and Enteric Glial Cells.

Until recently, glia were considered to be a structural support for neurons, however further investigations showed that glial cells are equally as important as neurons. Among many different types of glia, enteric glial cells (EGCs) found in the gastrointestinal tract, have been significantly underestimated, but proved to play an essential role in neuroprotection, immune system modulation and many other functions. They are also said to be remarkably altered in different physiopathological conditions. A nutraceutical is defined as any food substance or part of a food that provides medical or health benefits, including prevention and treatment of the disease. Following the description of these interesting peripheral glial cells and highlighting their role in physiological and pathological changes, this article reviews all the studies on the effects of nutraceuticals as modulators of their functions. Currently there are only a few studies available concerning the effects of nutraceuticals on EGCs. Most of them evaluated molecules with antioxidant properties in systemic conditions, whereas only a few studies have been performed using models of gastrointestinal disorders. Despite the scarcity of studies on the topic, all agree that nutraceuticals have the potential to be an interesting alternative in the prevention and/or treatment of enteric gliopathies (of systemic or local etiology) and their associated gastrointestinal conditions.

Changes in Fatty Acid Dietary Profile Affect the Brain-Gut Axis Functions of Healthy Young Adult Rats in a Sex-Dependent Manner.

Dietary modifications, including those affecting dietary fat and its fatty acid (FA) composition, may be involved in the development of brain-gut axis disorders, with different manifestations in males and females. Our aim was to evaluate the impact of three purified diets with different FA composition on the brain-gut axis in rats of both sexes. Male and female Wistar rats fed a cereal-based standard diet from weaning were used. At young adult age (2-3 months old), animals were divided into three groups and treated each with a different refined diet for 6 weeks: a control group fed on AIN-93G diet containing 7% soy oil (SOY), and two groups fed on AIN-93G modified diets with 3.5% soy oil replaced by 3.5% coconut oil (COCO) or 3.5% evening primrose oil (EP). Different brain-gut axis parameters were evaluated during 4-6 weeks of dietary intervention. Compared with SOY diet (14% saturated FAs, and 58% polyunsaturated FAs), COCO diet (52.2% saturated FAs and 30% polyunsaturated FAs) produced no changes in brain functions and minor gastrointestinal modifications, whereas EP diet (11.1% saturated FAs and 70.56% polyunsaturated FAs) tended to decrease self-care behavior and colonic propulsion in males, and significantly increased exploratory behavior, accelerated gastrointestinal transit, and decreased cecum and fecal pellet density in females. Changes in FA composition, particularly an increase in ω-6 polyunsaturated FAs, seem to facilitate the development of brain-gut axis alterations in a sex-dependent manner, with a relatively higher risk in females.

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.

Bioaccesibility, Metabolism, and Excretion of Lipids Composing Spent Coffee Grounds.

The bioaccessibility, metabolism, and excretion of lipids composing spent coffee grounds (SCGs) were investigated. An analysis of mycotoxins and an acute toxicity study in rats were performed for safety evaluation. Total fat, fatty acids, and diterpenes (cafestol and kahweol) were determined in SCGs and their digests obtained in vitro. A pilot repeated intake study was carried out in Wistar rats using a dose of 1 g SCGs/kg b.w. for 28 days. Fat metabolism was evaluated by analysis of total fat, cholesterol, and histology in liver. The dietary fiber effect of SCGs was measured radiographically. The absence of mycotoxins and toxicity was reported in SCGs. A total of 77% of unsaturated fatty acids and low amounts of kahweol (7.09 µg/g) and cafestol (414.39 µg/g) were bioaccessible after in vitro digestion. A significantly lower (p < 0.1) accumulation of lipids in the liver and a higher excretion of these in feces was found in rats treated with SCGs for 28 days. No lipid droplets or liver damage were observed by histology. SCGs acutely accelerated intestinal motility in rats. SCGs might be considered a sustainable, safe, and healthy food ingredient with potential for preventing hepatic steatosis due to their effect as dietary fiber with a high fat-holding capacity.

Specimen preparation for "block face" scanning electron microscopy (BFSEM). An energy-dispersive X-ray spectroscopy study

In this paper we describe a SEM block-face technique in which block faces of large dimensions can be examined in a high-resolution SEM under high vacuum. The results of different tissue contrast methods have been studied and, in addition to osmium, potassium permanganate has been used as a staining medium for the first time in BFSEM. The study also examined the effects of uranyl acetate and phosphotungstic acid. The following organs of adult albino rats were examined: colonic mucosa, spinal ganglion, anterior pituitary gland and exocrine pancreas.Six preparation protocols, referred to here as treatments, were applied and evaluated according to three criteria: 1st the visual quality of the digital images, 2nd the measurements of the signal-noise ratio (SNR) of the digital images with and without beam deceleration (BD), and 3rd the X-ray microanalysis of samples, treated according to the 6 proposed protocols, demonstrating the presence and relative quantity of the elements used to stain the cellular structures, enabling visualisation with the electron microscope. In conclusion, it can be said that treatments with osmium produced better results than those containing potassium permanganate. Treatments with the addition of thiocarbohydrazide (TCH) considerably increased the osmium deposits (ligand effect) and proved highly effective. Finally, it should be noted that the method proposed, called here 2D BFSEM, can be very useful not only in histology but also in histo-pathology, for example in the study of biopsies and - last but not least - in embryology: all these are situations in which it is important to avoid a loss of material due to preparation exigencies

No disponible

The isolated colonic mucosa: a new substrate for tissue reconstruction. Isolation, decellularization and characterization by immunohistochemistry and electron microscopy

This study proposes the use of isolated colonic mucosa as a "scaffold" for cell cultures and potentially for tissue reconstruction. The main goal of this study was to obtain complete decellularization of the specimens while preserving the superficial basement membrane (BM) as a place for cell attachment and growth. This decellularization technique uses a chelating agent in combination with mechanical vibration, followed by detergents and DNase. The grade of decellularization achieved is assessed by counting the number of cell nuclei stained with propidium iodide (PI). BM marker proteins such as collagen IV, laminin and perlecan were detected by immunohistochemistry (ICC). Transmission (TEM) and scanning electron microscopy (SEM) were used to examine the BM ultrastructure and surface topography. The results show that the protocol used is suitable for rat colonic mucosa. During the process, material of the lamina lucida (LL) was partly removed from the BM, whereas the lamina densa (LD) seems to have remained unchanged. The BM had become thinner than the control specimens. The nanotopography of the BM surface is characterized by globules of 34-60 nm in diameter. Human fetal fibroblasts were successfully cultured on this substrate confirming that cells can adhere to and grow on this substrate, at least for the particular cell line used. It can be said that the colonic mucosa is an interesting substrate for in vitro stud-ies with cells and presumably also for tissue reconstruction

No disponible