Calcium influx and spermatogenesis in the testis and liver enzyme activities in the zebrafish are rapidly modulated by the calcium content of the water.

This study investigated the effects of varying environmental Ca2+ concentrations on the influx of Ca2+ to the testis, testicular morphology, and liver enzymes in the zebrafish. Adult zebrafish (Danio rerio) were held in water containing low (0.02 mM), control (0. 7 mM) or high (2 mM) Ca2+ concentrations for 12 h. Testes were then incubated in vitro with 0.1 µCi/mL 45Ca2+ to measure Ca2+ influx at 30 and 60 min and qualitative and quantitative testicular histological analyses were conducted. In addition, activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT), enzymes that indicate tissue damage, were evaluated in the liver. The testes from zebrafish exposed in vivo to low (0.02 mM) and high (2 mM) Ca2+ content water had a higher Ca2+ influx than the control group after 30 min of incubation, and at 60 min (high Ca2+ group only). There were morphological changes in the testes from the low and high Ca2+ groups including spermatozoa distributed in dense agglomerates and apoptotic cells. Furthermore, zebrafish exposed to high Ca2+ containing water had an increased density of haploid cells (spermatids and spermatozoa). In addition, both low and high Ca2+ water affected liver function by increasing ALT and GGT activities. Collectively, these studies show that alterations in calcium homeostasis in the testis, stimulation of the spermatogenic wave and hepatic injury were rapid responses to changes in the concentration of Ca2+ in the water.

Sulfonyl(thio)urea derivative induction of insulin secretion is mediated by potassium, calcium, and sodium channel signal transduction.

AIM: To investigate the mechanism of action of sulfonyl(thio)urea derivative (SD) on glycemia and on insulin secretion in pancreatic islets. METHODS: Wistar rats were divided into hyperglycemic control group, rats received 4 g/kg body weight glucose plus sitagliptin 10 mg/kg (p.o.); hyperglycemic plus SD 10 mg/kg (p.o.); hyperglycemic plus SD plus sitagliptin. Blood was collected before glucose overloading (zero time), and at 15, 30, 60, and 180 min after glucose, from the afore mentioned groups for glycemia and glucagon-like peptide 1 (GLP-1) measurements and intestinal disaccharidases activity. Pancreatic islets were isolated for the calcium influx and insulin secretion in in vitro studies. RESULTS: SD reduced glycemia and increased GLP-1 secretion, while inhibited sucrase and lactase activity. This SD (1.0 and 10.0 µM) stimulated calcium influx in a similar percentile to that of glibenclamide, and in a nonsynergic manner. In addition, the trigger effect of SD on calcium influx was through the K+ -ATP-dependent channels, and partially by activating voltage-dependent K + channels and voltage-dependent calcium channels. Furthermore, SD-stimulated Na + and Ca 2+ entry, induced by the transient receptor potential ankyrin 1 and by modulation of Na + /Ca 2+ exchange. The activation of these pathways by SD culminated in in vitro insulin secretion, reinforcing the critical role of K + -ATP channels in the secretagogue effect of SD. CONCLUSIONS: SD diminish glycemia by inducing GLP-1 secretion and inhibiting disaccharidases. To our knowledge, this is the first report of an insulin secretagogue effect of SD that is mediated by potassium and calcium, as well as sodium, signal transduction.

The potent insulin secretagogue effect of betulinic acid is mediated by potassium and chloride channels.

Betulinic acid (BA) has been described as an insulin secretagogue which may explain its potent antihyperglycemic effect; however, the exact role of BA as an insulinogenic agent is not clear. The aim of this study was to investigate the mechanism of BA on calcium influx and static insulin secretion in pancreatic islets isolated from euglycemic rats. We found that BA triggers calcium influx by a mechanism dependent on ATP-dependent potassium channels and L-type voltage-dependent calcium channels. Additionally, the voltage-dependent and calcium-dependent chloride channels are also involved in the mechanism of BA, probably due to an indirect stimulation of calcium entry and increased intracellular calcium. Additionally, the downstream activation of PKC, which is necessary for the effect of BA on calcium influx, is involved in the full stimulatory response of the triterpene. BA stimulated the static secretion of insulin in pancreatic islets, indicating that the abrupt calcium influx may be a key step in its secretagogue effect. As such, BA stimulates insulin secretion through the activation of electrophysiological mechanisms, such as the closure of potassium channels and opening of calcium and chloride channels, inducing cellular depolarization associated with metabolic-biochemical effects, in turn activating PKC and ensuring the secretion of insulin.

Juçara (Euterpe edulis Martius) improves time-to-exhaustion cycling performance and increased reduced glutathione: a randomized, placebo-controlled, crossover, and triple-blind study.

To examine the effects of 7-days juçara powder (JP) intake on oxidative stress biomarkers and endurance and sprint cycling performances. In a randomized, placebo-controlled, crossover, and triple-blind study, 20 male trained cyclists were assigned to intake 10 g of JP (240 mg anthocyanins) or placebo (PLA) for 7 days and performed a cycling time-to-exhaustion (TTE). A 5 s cycling sprint was performed before and after the cycling TTE. Blood oxidative stress biomarkers and lactate concentration where evaluated 1 h before (T-1), immediately after (T0), and 1 h after (T1) the cycling TTE. The mean duration time for the cycling TTE was 8.4 ± 6.0% (63 ± 17 s) longer in the JP condition (JP: 751 ± 283 s) compared to PLA (688 ± 266 s) (P < 0.019). Two-way repeated measures Analysis of variance showed an increase in the JP condition for reduced glutathione (GSH) (P = 0.049) at T0 (P = 0.039) and T1 (P = 0.029) compared to PLA with a moderate effect size at T0 (d = 0.61) and T1 (d = 0.57). Blood lactate levels increased over time in both conditions (P ≤ 0.001). No differences were observed for the post-TTE sprint fatigue index, total phenols, protein carbonyls, and glutathione peroxidase activity. Seven-day intake of JP improved cycling endurance performance and increased GSH levels but had no effect on lactate and cycling sprint-induced fatigue.

The effect of oral dietary interventions on nutritional status and treatment tolerance in patients with hematologic neoplasms receiving chemotherapy: a systematic review.

CONTEXT: Adverse events from chemotherapy treatment affect food intake, nutritional status, and treatment tolerance in cancer patients. However, the effect of nutritional intervention in patients with hematologic neoplasms receiving chemotherapy remains unknown. OBJECTIVE: The aim of this systematic review was to evaluate the evidence on nutritional interventions on nutritional status, treatment tolerance, inflammatory markers, quality of life, and mortality in patients with hematologic neoplasms receiving chemotherapy. DATA SOURCES: The MEDLINE, LILACS, CINAHL, Web of Science, Embase, ICTRP, CENTRAL, and ClinicalTrials.gov databases were searched. Additional literature and the bibliographies of identified articles were also considered. DATA EXTRACTION: Randomized controlled trials in individuals with hematologic neoplasms receiving chemotherapy along with nutritional counseling and oral nutritional supplementation, and intake of supplementary food products, alone or in combination, were assessed as criteria of interest. The data were extracted independently by 2 researchers. The risk of bias was assessed through the Cochrane risk-of-bias tool (RoB 2). DATA ANALYSIS: Ten studies were included up to August 15, 2022 (updated in November of 2022). With regard to the outcomes, 4 studies assessed nutritional status and 2 studies showed a positive result of the intervention on some of the markers. Seven studies assessed certain markers of treatment tolerance and only 2 studies showed improvement in the outcome after the intervention. CONCLUSION: The studies that found positive results are quite different from each other in terms of intervention, study time, and design. More randomized controlled trials are needed to test different dietary interventions using placebo and blinding, when possible, and with reduced sample variability in individuals with hematologic neoplasms receiving chemotherapy. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42020196765.

Influence of the aquatic environment and 1α,25(OH)2 vitamin D3 on calcium influx in the intestine of adult zebrafish.

We investigated the effects of environment calcium challenge and 1α,25(OH)2 vitamin D3 (1,25-D3) on 45Ca2+ influx in the intestine of zebrafish (ZF). In vitro45Ca2+ influx was analyzed using intestines from fed and fasted fish. ZF were held in water containing Ca2+ (0.02, 0.7, 2.0 mM) to analyze the ex vivo45Ca2+ influx in the intestine and for histology. Intestines from fish held in water with Ca2+ were incubated ex vivo to characterize ion channels, receptors, ATPases and ion exchangers that orchestrate 45Ca2+ influx. For in vitro studies, intestines were incubated with antagonists/agonist or inhibitors to study the mechanism of 1,25-D3 on 45Ca2+ influx. Fasted ZF reached a plateau for 45Ca2+ influx at 30 min. In vivo fish at high Ca2+ stimulated ex vivo45Ca2+ influx and increased the height of intestinal villi in low calcium. In the normal calcium, 45Ca2+ influx was maintained by the reverse-mode Na+/Ca2+ (NCX) activation, Na+/K+-ATPase pump and sarco/endoplasmic reticulum calcium ATPase (SERCA) pump. However, Ca2+ hyperosmolarity is supported by L-type voltage-dependent calcium channels (L-VDCC), transient receptor potential vanilloid subfamily 1 (TRPV1) and Na+/K+-ATPase activity. The calcium challenge causes morphological alteration and changes the ion type-channels involved in the intestine to maintain hyperosmolarity. 1,25-D3 stimulates Ca2+ influx in normal osmolarity coordinated by L-VDCC activation and SERCA inhibition to keeps high intracellular calcium in intestine. Our data showed that the adult ZF regulates the calcium challenge (per se osmolarity), independently of the hormonal regulation to maintain the calcium balance through the intestine to support ionic adaptation.

Biological activity of 2α,3ß,23-trihydroxyolean-12-ene on glucose homeostasis.

We studied the effect and the mechanisms of action of 2α,3ß,23-trihydroxyolean-12-ene (THO), from Croton heterodoxus Baill. (Euphorbiaceae), in glucose uptake in hyperglycemic rats. The effect of in vivo pretreatment with THO in hyperglycemic rats was analyzed. The in vitro effects of THO were observed in adipocytes and in adipose tissue. THO reduced glycemia, in part by increasing serum insulin and augmenting the disposal of glucose as glycogen in hepatocytes but did not change the serum concentration of glucagon-like peptide-1. THO increased glucose uptake in adipocytes and in adipose tissue by a mechanism dependent on phosphatidylinositol 3-kinase vesicular traffic and on the process of vesicle fusion at the plasma membrane in regions containing cholesterol, indicating the involvement of glucose transporter-4 (GLUT4). This triterpene may act solely via the activation and translocation of GLUT4 (rather than via nuclear actions, such as upregulation of GLUT4 synthesis), since THO did not alter the amount of GLUT4 mRNA or the content of GLUT4. Consistent with these data, the stimulatory effect of this triterpene on the quantity of GLUT4 in the membrane fraction was dependent upon p38 phosphorylation. In this experimental model, orally administered 10 mg/kg THO did not modulate extracellular serum lactate dehydrogenase. In conclusion, THO decreases hyperglycemia by increasing serum insulin and hepatic glycogen content. The THO mechanism of action on adipose tissue for glucose uptake is suggested to be via GLUT4 translocation stimulation mediated by a p38-dependent mechanism. THO is a potential antihyperglycemic agent that acts in a target tissue for glucose homeostasis.

Acute exposure to bis(2-ethylhexyl)phthalate disrupts calcium homeostasis, energy metabolism and induces oxidative stress in the testis of Danio rerio.

Bis(2-ethylhexyl)phthalate (BEHP) negatively affects testicular functions in different animal species, disturbing reproductive physiology and male fertility. The present study investigated the in vitro acute effect of BEHP on the mechanism of action of ionic calcium (Ca2+) homeostasis and energy metabolism. In addition, the effect of BEHP on oxidative stress was studied in vitro and in vivo in the testis of Danio rerio (D. rerio). Testes were treated in vitro for 30 min with 1 µM BEHP for 45Ca2+ influx measurements. Testes were also incubated with 1 µM BEHP for 1 h (in vitro) or 12 h (in vivo) for the measurements of lactate content, 14C-deoxy-d-glucose uptake, lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (GGT) activity, total reactive oxygen species (ROS) production and lipid peroxidation. In addition, the effect of BEHP (1 µM) on GGT, glutamic oxaloacetic transferase (GOT) and glutamic pyruvic transferase (GPT) activity in the liver was evaluated after in vivo treatment for 12 h. BEHP disturbs the Ca2+ balance in the testis when given acutely in vitro. BEHP stimulated Ca2+ influx occurs through L-type voltage-dependent Ca2+ channels (L-VDCC), transitory receptor potential vaniloid (TRPV1) channels, reverse-mode Na+/Ca2+ exchanger (NCX) activation and inhibition of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA). BEHP affected energy metabolism in the testis by decreasing the lactate content and LDH activity. In vitro and in vivo acute effects of BEHP promoted oxidative stress by increasing ROS production, lipid peroxidation and GGT activity in the testis. Additionally, BEHP caused liver damage by increasing GPT activity.

Influência da vitamina C na lipoperoxidação hepática e muscular de camundongos C57BL/6 submetidos à dieta de cafeteria / Influence of vitamin C on hepatic and muscular lipoperoxidation of C57BL / 6 mice conducted on the cafeteria diet

Analisar o efeito do tratamento com vitamina C sobre a lipoperoxidação hepática e muscular, assim como sobre parâmetros bioquímicos de camundongos C57BL/6 submetidos à dieta de cafeteria durante nove semanas. Dezessete camundongos da linhagem C57BL/6, com dois meses de idade foram alocados em três grupos: 1) Controle, 2) Cafeteria e 3) Cafeteria + Vitamina C. O ensaio biológico foi conduzido por nove semanas, os animais foram mantidos em jejum de doze horas, e depois de sacrificados, o sangue e os tecidos foram coletados para dosagens bioquímicas. A partir de amostras de fígado e músculo sóleo, foram quantificados os teores de espécies reativas ao ácido tiobarbitúrico (TBARS) e de lipídeos totais. Os fígados dos camundongos alimentados com dieta de cafeteria tratados ou não com vitamina C apresentaram maiores teores de TBARS comparados aos controles (p<0,05). Já o teor de TBARS muscular foi maior nos camundongos do grupo Cafeteria + Vitamina C comparado àquele encontrado para os animais Cafeteria e Controle (p<0,05). As concentrações de colesterol hepático e muscular foram mais elevadas no grupo Cafeteria + Vitamina C comparadas às dos grupos Controle e Cafeteria (p<0,05). O tratamento com vitamina C aumentou a lipoperoxidação muscular, mas não influenciou esse parâmetro no fígado de camundongos C57BL/6 alimentados com dieta de cafeteria. Além disso, a vitamina C elevou a concentração de colesterol nos tecidos hepático e muscular, mas não alterou a glicemia e os lipídeos séricos dos animais após nove semanas de tratamento.(AU)

To analyze the effect of vitamin C treatment on hepatic and muscular lipoperoxidation, as well as on biochemical parameters of C57BL / 6 mice submitted to the cafeteria diet for nine weeks. Seventeen mice of the C57BL / 6 lineage, two months old, were allocated to three groups: 1) Control, 2) Cafeteria and 3) Cafeteria + Vitamin C. The biological assay was conducted for nine weeks, the animals were kept in fasting for 12 hours and after being sacrificed, blood and tissues were collected for biochemical dosages. From the samples of liver and muscle, the contents of thiobarbituric acid reactive species (TBARS) and total lipids were quantified. The livers of mice fed with a diet of coffee or not treated with vitamin C showed higher levels of TBARS compared to controls (p <0.05). The muscle TBARS content was higher in the mice of the Cafeteria + Vitamin C group compared to that found for the Cafeteria and Control animals (p <0.05). The concentrations of hepatic and muscular cholesterol were higher in the Cafeteria + Vitamin C group compared to the Control and Cafeteria groups (p <0.05). Treatment with vitamin C increased muscle lipoperoxidation, but did not influence this parameter in the liver of C57BL 6 mice fed with cafeteria diet. In addition, vitamin C increased cholesterol concentration in liver and muscle tissues, but did not change serum glycemia and serum lipids after nine weeks of treatment.(AU)

The effect of vitamin C supplementation on neutropenia induced by cyclophosphamide in mice / Efecto con la suplementación de vitamina C sobre la neutropenia inducida por ciclofosfamida en ratones

ABSTRACT Neutropenia is one of the adverse effects caused by the administration of chemotherapy drugs. The present study aimed at investigating the effect of vitamin C supplementation in a model of immunosuppression induced by cyclophosphamide in mice. Vitamin C supplementation (50 mg/kg/day) administered intraperitoneally (i.p.) for 7 consecutive days in adult Swiss albino female. Mice were divided into four groups (n= 8/group): 1. Control (only distilled water i.p.), 2. Cyclophosphamide group (cyclophosphamide i.p. 150 and 100 mg/kg on days 1 and 4, respectively and distilled water daily), 3. Vitamin C group (Vitamin C 50 mg/kg i.p. and distilled water daily), and 4. Cyclophosphamide and Vitamin C group (cyclophosphamide i.p. 150 and 100 mg/kg on days 1 and 4, respectively and vitamin C 50 mg/kg i.p. daily). Vitamin C did not interfere in leukocytes count, but when co-administered with cyclophosphamide, significant interaction was observed, intensifying the neutropenia caused by cyclophosphamide. Vitamin C did not influence body weight during treatment, but groups receiving cyclophosphamide had a significant weight loss from the third day of treatment until the end of experiment compared to the control group. Vitamin C supplementation intensified neutropenia induced by cyclophosphamide and did not prevent weight loss induced by cyclophosphamide in mice.

RESUMEN La neutropenia es uno de los efectos adversos causados por la administración de medicamentos de quimioterapia. El presente estudio tuvo como objetivo investigar el efecto de la administración de suplementos de vitamina C en un modelo de inmunosupresión inducida por ciclofosfamida en ratones. Se realizó la suplementación de vitamina C (50 mg/kg/día) administrada por vía intraperitoneal (i.p) por 7 días en ratones hembras swiss albinas adultas. Los ratones fueron divididos en cuatro grupos (n= 8 / grupo): Control (solamente agua destilada i.p) Ciclofosfamida (ciclofosfamida i.p. 150 mg/kg y 100 mg/kg en el día 1 y día 4 y agua destilada diariamente) Vitamin C (vitamina C 50 mg/kg i.p y agua destilada diariamente), Ciclofosfamida y Vit C (ciclofosfamida i.p. 150 y 100 mg/kg en el día 1 y día 4 y vitamina C 50 mg/kg i.p. diariamente). La vitamina C por sí no interfirió en los valores de leucocitos y tampoco influyó en el peso corporal durante el tratamiento, pero los grupos que recibieron ciclofosfamida tuvieron una pérdida de peso significativa desde el tercer día de tratamiento hasta el final del experimento en comparación con el grupo control. La suplementación de vitamina C intensificó la neutropenia inducida por ciclofosfamida y no evitó la pérdida de peso inducida por ciclofosfamida en ratones.