Insulin in combination with pioglitazone prevents advanced cachexia in 256-Walker tumor-bearing rats: effect is greater than treatment alone and is associated with improved insulin sensitivity.

BACKGROUND: Insulin (INS) resistance and hypoinsulinemia commonly observed in cancer-carrying, can contribute to cachexia. However, the effects of INS and INS sensitizers, such as pioglitazone (PIO), particularly when used in combination therapy, on cancer cachexia have not been evaluated sufficiently. We investigated the effects of INS and PIO, at various doses, either isolated or combined, on cachexia in Walker-256 tumor-bearing rats (TB rats). METHODS: INS or INS + PIO were administered in TB rats, for 6 or 12 days, starting from the day of tumor cells inoculation. RESULTS: INS at 18 or 27 U/kg (12-days treatment), but not 9 U/kg, reduced fat loss and slightly prevented weight loss. However, INS 18 U/kg + PIO 5, 10, 20, or 40 mg/kg (6 or 12-day treatment) reduced fat loss and markedly prevented weight loss but did not affect muscle wasting. While TB rats lost weight (37.9% in 12 days), TB rats treated with INS 18 U/kg + PIO 5 mg/kg showed pronounced weight gain (73.7%), which was greater than the sum (synergism) of the weight gains promoted by isolated treatments with INS 18 U/kg (14.7%) or PIO 5 mg/kg (13.1%). The beneficial effect of the INS 18 U/kg + PIO 5 mg/kg on weight loss was associated with improved INS sensitivity, as indicated by the higher blood glucose clearance constant (kITT), decreased levels of free fatty acids and triacylglycerols (INS resistance-inducing factors) in the blood, and increased expression of p-Akt (INS signaling pathway protein) in adipose tissue. CONCLUSIONS: The combined treatment with INS 18 U/kg + PIO 5 mg/kg was more effective in preventing advanced cachexia in TB rats than each treatment alone, emerging as the best approach, considering the lower dosage and higher efficacy. This combination completely preserved adipose mass and markedly reduced weight loss through a synergistic mechanism linked to improved insulin sensitivity. These findings provide new insights into the importance of drug combinations in effectively combating fat loss in advanced cachexia.

Peripheral insulin resistance is early, progressive, and correlated with cachexia in Walker-256 tumor-bearing rats.

Insulin (INS) resistance is often found in cancer-bearing, but its correlation with cachexia development is not completely established. This study investigated the temporal sequence of the development of INS resistance and cachexia to establish the relationship between these factors in Walker-256 tumor-bearing rats (TB rats). INS hepatic sensitivity and INS resistance-inducing factors, such as free fatty acids (FFA) and tumor necrosis factor-α (TNF-α), were also evaluated. Studies were carried out on Days 2, 5, 8, and/or 12 after inoculation of tumor cells in rats. The peripheral INS sensitivity was assessed by the INS tolerance test and the INS hepatic sensitivity in in situ liver perfusion. TB rats with 5, 8, and 12 days of tumor, but not 2 days, showed decreased peripheral INS sensitivity (INS resistance), retroperitoneal fat, and body weight, compared to healthy rats, which were more pronounced on Day 12. Gastrocnemius muscle wasting was observed only on Day 12 of tumor. The peripheral INS resistance was significantly correlated (r = -.81) with weight loss. Liver INS sensitivity of TB rats with 2 and 5 days of tumor was unchanged, compared to healthy rats. TB rats with 12 days of tumor showed increased plasma FFA and increased TNF-α in retroperitoneal fat and liver, but not in the gastrocnemius, compared to healthy rats. In conclusion, peripheral INS resistance is early, starts along with fat and weight loss and before muscle wasting, progressive, and correlated with cachexia, suggesting that it may play an important role in the pathogenesis of the cachectic process in TB rats. Therefore, early correction of INS resistance may be a therapeutic approach to prevent and treat cancer cachexia.

Molecular and cellular mechanisms involved in tissue-specific metabolic modulation by SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) is triggered by the SARS-CoV-2, which is able to infect and cause dysfunction not only in lungs, but also in multiple organs, including central nervous system, skeletal muscle, kidneys, heart, liver, and intestine. Several metabolic disturbances are associated with cell damage or tissue injury, but the mechanisms involved are not yet fully elucidated. Some potential mechanisms involved in the COVID-19-induced tissue dysfunction are proposed, such as: (a) High expression and levels of proinflammatory cytokines, including TNF-α IL-6, IL-1ß, INF-α and INF-ß, increasing the systemic and tissue inflammatory state; (b) Induction of oxidative stress due to redox imbalance, resulting in cell injury or death induced by elevated production of reactive oxygen species; and (c) Deregulation of the renin-angiotensin-aldosterone system, exacerbating the inflammatory and oxidative stress responses. In this review, we discuss the main metabolic disturbances observed in different target tissues of SARS-CoV-2 and the potential mechanisms involved in these changes associated with the tissue dysfunction.

Infusion of high concentration of lactate in perfused liver, simulating in vivo hyperlactatemia, prevents the reduction of gluconeogenesis in Walker-256 tumor-bearing rats.

Gluconeogenesis (GN) is increased in patients with cancer cachexia, but is reduced in liver perfusion of Walker-256 tumor-bearing cachectic rats (TB rats). The causes of these differences are unknown. We investigated the influence of circulating concentrations of lactate (NADH generator) and NADH on GN in perfused livers of TB rats. Lactate, at concentrations similar to those found on days 5 (3.0 mM), 8 (5.5 mM), and 12 (8.0 mM) of the tumor, prevented the reduction of GN from 2.0 mM lactate (lactatemia of healthy rat) in TB rats. NADH, 50 or 75 µM, but not 25 µM, increased GN from 2.0 mM lactate in TB rats to higher values than healthy rats. High concentrations of pyruvate (no NADH generator, 5.0 and 8.0 mM) did not prevent the reduction of GN from 2.0 mM pyruvate in TB rats. However, 50 or 75 µM NADH, but not 25 µM, increased GN from 2.0 mM pyruvate in TB rats to similar or higher values than healthy rats. High concentration of glutamine (NADH generator, 2.5 mM) or 50 µM NADH prevented the reduction of GN from 1 mM glutamine in TB rats. Intraperitoneal administration of pyruvate (1.0 mg/kg) or glutamine (0.5 mg/kg) similarly increased the glycemia of healthy and TB rats. In conclusion, high lactate concentration, similar to hyperlactatemia, prevented the reduction of GN in perfused livers of TB rats, an effect probably caused by the increased redox potential (NADH/NAD+ ). Thus, the decreased GN in livers from TB rats is due, at least in part, to the absence of simulation of in vivo hyperlactatemia in liver perfusion studies.

Effects of metformin on insulin resistance and metabolic disorders in tumor-bearing rats with advanced cachexia.

Metformin (MET) is widely used in the correction of insulin (INS) resistance and metabolic abnormalities in type 2 diabetes. However, its effect on INS resistance and metabolic disorders associated with cancer cachexia is not established. We investigated the MET effects, isolated or associated with INS, on INS resistance and metabolic changes induced by Walker-256 tumor in rats with advanced cachexia. MET (500 mg·kg-1, oral) and MET + INS (1.0 IU·kg-1, s.c.) were administered for 12 days, starting on the day of tumor cell inoculation. Tumor-bearing rats showed adipose and muscle mass wasting, body mass loss, anorexia, decreased Akt phosphorylation in retroperitoneal and mesenteric adipose tissue, peripheral INS resistance, hypoinsulinemia, reduced INS content and secretion from pancreatic islets, and also inhibition of glycolysis, gluconeogenesis, and glycogenolysis in liver. MET and MET + INS treatments did not prevent these changes. It can be concluded that treatments with MET and MET + INS did not prevent the adipose and muscle mass wasting and body mass loss of tumor-bearing rats possibly by not improving INS resistance. Therefore, MET, used for the treatment of INS resistance in type 2 diabetes, is not effective in improving INS resistance in the advanced stage of cancer cachexia, evidencing that the drug does not have the same beneficial effect in these 2 diseases.

Pioglitazone improves insulin sensitivity and reduces weight loss in Walker-256 tumor-bearing rats.

AIM: The lipogenic effect of pioglitazone (PGZ), an insulin (INS) sensitizer, is well established. However, few studies have evaluated PGZ effects in preventing weight loss in cancer. We investigated PGZ effects, alone or associated with INS, on INS resistance, cachexia and metabolic abnormalities induced by Walker-256 tumor in rats. MAIN METHODS: PGZ (5.0mg·kg-1, oral) or PGZ+INS (NPH, 1.0UI·kg-1, sc), were once-daily administered during 12days, starting on the day inoculation of Walker-256 tumor cells. Rats were separated in small (about 17g) and big (about 30g) tumor-bearing. KEY FINDINGS: Big tumor-bearing rats showed greater cachexia, blood triacylglycerol and free fatty acids and INS resistance. PGZ and PGZ+INS treatments did not change tumor growth and food intake, but reduced several abnormalities such as INS resistance, increased blood free fatty acids, retroperitoneal fat wasting and body weight loss in small tumor-bearing rats. The prevention of retroperitoneal fat wasting did not involve reduction of tumor necrosis factor-α expression increased. In big tumor-bearing rats, PGZ and PGZ+INS treatments reversed the high blood triacylglycerol and free fatty acids levels, but had no effect on other parameters. SIGNIFICANCE: PGZ and PGZ+INS improved INS peripheral sensitivity, possibly by decreasing blood free fatty acids, and reduced fat tissue wasting and body weight loss in small tumor-bearing rats. The results suggest clinical benefits of PGZ in preventing INS resistance, adipose tissue wasting and weight loss when the tumor is small, i.e., in less severe cachexia.

Instant coffee extract with high chlorogenic acids content inhibits hepatic G-6-Pase in vitro, but does not reduce the glycaemia.

Coffee is the main source of chlorogenic acid in the human diet, and it contains several chlorogenic acid isomers, of which the 5-caffeoylquinic acid (5-CQA) is the predominant isomer. Because there are no available data about the action of chlorogenic acids from instant coffee on hepatic glucose-6-phosphatase (G-6-Pase) activity and blood glucose levels, these effects were investigated in rats. The changes on G-6-Pase activity and liver glucose output induced by 5-CQA were also investigated. Instant coffee extract with high chlorogenic acids content (37.8%) inhibited (p < 0.05) the G-6-Pase activity of the hepatocyte microsomal fraction in a dose-dependent way (up to 53), but IV administration of this extract did not change the glycaemia (p > 0.05). Similarly, 5-CQA (1 mM) reduced (p < 0.05) the activity of microsomal G-6-Pase by about 40%, but had no effect (p > 0.05) on glucose output arising from glycogenolysis in liver perfusion. It was concluded that instant coffee extract with high content of chlorogenic acids inhibited hepatic G-6-Pase in vitro, but failed to reduce the glycaemia probably because the coffee chlorogenic acids did not reach enough levels within the hepatocytes to inhibit the G-6-Pase and reduce the liver glucose output.

The central administration of C75, a fatty acid synthase inhibitor, activates sympathetic outflow and thermogenesis in interscapular brown adipose tissue.

The present work investigated the participation of interscapular brown adipose tissue (IBAT), which is an important site for thermogenesis, in the anti-obesity effects of C75, a synthetic inhibitor of fatty acid synthase (FAS). We report that a single intracerebroventricular (i.c.v.) injection of C75 induced hypophagia and weight loss in fasted male Wistar rats. Furthermore, C75 induced a rapid increase in core body temperature and an increase in heat dissipation. In parallel, C75 stimulated IBAT thermogenesis, which was evidenced by a marked increase in the IBAT temperature that preceded the rise in the core body temperature and an increase in the mRNA levels of uncoupling protein-1. As with C75, an i.c.v. injection of cerulenin, a natural FAS inhibitor, increased the core body and IBAT temperatures. The sympathetic IBAT denervation attenuated all of the thermoregulatory effects of FAS inhibitors as well as the C75 effect on weight loss and hypophagia. C75 induced the expression of Fos in the paraventricular nucleus, preoptic area, dorsomedial nucleus, ventromedial nucleus, and raphé pallidus, all of which support a central role of FAS in regulating IBAT thermogenesis. These data indicate a role for IBAT in the increase in body temperature and hypophagia that is induced by FAS inhibitors and suggest new mechanisms explaining the weight loss induced by these compounds.

Changes in liver gluconeogenesis during the development of Walker-256 tumour in rats.

Few studies have investigated liver gluconeogenesis in cancer and there is no agreement as to whether the activity of this pathway is increased or decreased in this disease. The aim of this study was to evaluate gluconeogenesis from alanine, pyruvate and glycerol, and related metabolic parameters in perfused liver from Walker-256 tumour-bearing rats on days 5 (WK5 group), 8 (WK8 group) and 12 (WK12 group) of tumour development. There was reduction (P < 0.05) of liver glucose production from alanine and pyruvate in WK5, WK8 and WK12 groups, which was accompanied by a decrease (P < 0.05) in oxygen consumption. Moreover, there was higher (P < 0.05) pyruvate and lactate production from alanine in the WK5 group and a marked reduction (P < 0.05) of pyruvate and urea production from alanine in the WK12 group. In addition, liver glucose production and oxygen consumption from glycerol were not reduced in WK5, WK8 and WK12 groups. Thus the, the results show inhibition of hepatic gluconeogenesis from alanine and pyruvate, but not from glycerol, on days 5, 8 and 12 of Walker-256 tumour development, which can be attributed to the metabolic step in which the substrate enters the gluconeogenic pathway.

Changes in blood metabolic parameters during the development of Walker-256 tumour-induced cachexia in rats are not caused by decreased food intake.

Blood metabolic parameters of Walker-256 tumour-bearing rats, on days 5, 8, 11 and 14 after implantation of tumour, were compared with those of rats without tumour fed ad libitum (free-fed control) or with reduced feeding (pair-fed control), similar to the anorexic tumour-bearing rats. Cachexia parameters and tumour mass also were investigated. In general, especially on day 14 after implantation of tumour, there was reduction of body mass, gastrocnemius muscle mass, food intake and glycemia and increase of blood triacylglycerol, free fatty acids, lactate and urea, compared with free-fed controls rats. These changes did not occur in pair-fed control, except a slight reduction of glycemia. Pair-fed control showed no significant changes in blood cholesterol and glycerol in comparison with free-fed control, although there was reduction of cholesterol and increase of blood glycerol on day 14 after tumour implantation compared with pair-fed control. The results demonstrate that, besides the characteristic signs of the cachexia syndrome such as anorexia, weight loss and muscle catabolism, Walker-256 tumour-bearing rats show several blood metabolic alterations, some of which begin as early as day 5 after implantation of tumour, and are accentuated during the development of cachexia. Evidence that the alterations of blood metabolic parameters of tumour-bearing rats were not found in pair-fed control indicate that they were not caused by decreased food intake. These changes were probably mediated by factors produced by tumour or host tissue in response to the presence of tumour.

Investigation of the acute effect of leptin on the inhibition of glycogen catabolism by insulin in rat liver perfused in situ.

Leptin, a cytokine secreted by adipose tissue, has been implicated in the insulin resistance associated with obesity. Here we examined the acute influence of leptin at physiological (10 ng/ml) and supraphysiological (50 ng/ml and 100 ng/ml) concentrations on the inhibition of glycogen catabolism promoted by insulin in rat liver perfusion experiments. Perfusion of the liver with insulin (20 microU/ml) decreased the activation of glucose production (p < 0.05) and glycogenolysis by cAMP (3 microM). However, the infusion of leptin, at concentrations similar to those found in non-obese (10 ng/ml), obese (50 ng/ml), and morbidly obese (100 ng/ml) individuals did not influence the acute inhibitory effect of insulin (20 microU/ml) on glucose production and glycogenolysis stimulated by cAMP (p > 0.05).We conclude that neither physiological nor supraphysiological concentrations of leptin directly influence the inhibition of glycogen catabolism promoted by insulin in rat liver perfused in situ.

Leptin inhibits glycogen catabolism but does not modify acutely the suppressive effect of insulin on glucose production and glycogenolysis stimulated by 8-Br-cAMP in rat liver perfused in situ.

Leptin, a hormone secreted by the adipocytes, plays a central role in glucose metabolism and the action of insulin. Here we assessed, by means of rat-liver perfusion, the direct influence of physiological (10 ng/ml) and supraphysiological (50 or 100 ng/ml) concentrations of leptin on the suppressive effect of insulin on the glucose production and glycogenolysis stimulated by 8-bromoadenosine-3':5'-monophosphate (8-Br-cAMP). Portal infusion of insulin (20 microU/ml) or leptin (10 ng/ml) reduced (p<0.05) the glucose production and glycogenolysis induced by 8-Br-cAMP (0.3 microM). However, portal infusion of physiological (10 ng/ml) and supraphysiological (50 or 100 ng/ml) concentrations of leptin together with the insulin did not modify the suppressive effect of the latter on the glucose production and glycogenolysis stimulated by 8-Br-cAMP. Moreover, prolonging the period of leptin infusion from 20 to 40 min also failed to influence the liver response to insulin. Thus, we conclude that: (a) leptin, at physiological levels, has a direct and acute effect, inhibiting the glucose production and glycogenolysis stimulated by 8-Br-cAMP; (b) leptin, at either physiological or supraphysiological concentrations, has no short-term influence on the suppressive effect of insulin on glycogen catabolism stimulated by 8-Br-cAMP.

Chlorogenic acid reduces the plasma glucose peak in the oral glucose tolerance test: effects on hepatic glucose release and glycaemia.

The effects of chlorogenic acid (CA) on hepatic glucose output, blood glucose levels and on glucose tolerance were analysed. Hepatic uptake of CA and its effects on hepatic catabolism of L-alanine and glucose-6-phosphatase (G-6-Pase) activity were also evaluated. CA (1 mM) inhibited about 40% of G-6-Pase activity (p < 0.05) in the microsomal fraction of hepatocytes, but no effect was observed on production of glucose from gluconeogenesis or on L-alanine catabolism, at various concentrations of CA (0.33, 0.5 and 1 mM), in liver perfusion experiments. Since there were indications of a lack of uptake of CA by the liver, it is possible that this compound did not reach sufficiently high intracellular levels to inhibit the target enzyme. Accordingly, intravenous administration of CA also failed to provoke a reduction in blood glucose levels. However, CA did promote a significant reduction (p < 0.05) in the plasma glucose peak at 10 and 15 min during the oral glucose tolerance test, probably by attenuating intestinal glucose absorption, suggesting a possible role for it as a glycaemic index lowering agent and highlighting it as a compound of interest for reducing the risk of developing type 2 diabetes.

Prevalência de medicamentos utilizados por portadores de retardo mental da APAE de Londrina-Pr / Prevalence of medicines used by mentally-ill individuals of APAE, in Londrina

O retardo mental (RM), após anos de crenças e misticismos, finalmente passou a ser considerado uma afecção neurológica que deve ser tratada com intervenção médica. As drogas psicotrópicas, se administradas corretamente, podem permitir que os acometidos de RM recuperem a capacidade de interação social produtiva e reintegrem-se à sociedade. Este trabalho teve como objetivo verificar, por meio de estudo descritivo, a freqüência da utilização de medicamentos utilizados pelos alunos da APAE (Associação de Pais e Amigos dos Excepcionais) de Londrina-PR, caracterizar essas drogas e relacioná-las com as patologias mentais de maior prevalência na instituição. Para tanto, foi estudada uma população de 147 alunos matriculados no período de janeiro de 1989 a maio de 2003. Os medicamentos em uso encontrados foram: anticonvulsivantes, 52,4 por cento, neurolépticos, 3,4 por cento, hematopoiéticos, 2,7 por cento, anticolinérgicos e agentes pró-cinéticos, 0,7 por cento cada. Dentre os anticonvulsivantes, salientou-se o fenobarbital, com 29,8 por cento. A prevalência desses fármacos foi maior nos acometidos por paralisia cerebral, 62,1 por cento, e menor nos portadores de síndrome de Down, 17,24 por cento. Em conclusão, consideramos a necessidade de implementar projetos de pesquisa que focalizem a dinâmica dos profissionais que trabalham com portadores de RM, bem como de assistência às famílias carentes.