Chlorophyll treatment combined with photostimulation increases glycolysis and decreases oxidative stress in the liver of type 1 diabetic rats

Photodynamic therapy (PDT) promotes cell death, and it has been successfully employed as a treatment resource for neuropathic complications of diabetes mellitus (T1DM) and hepatocellular carcinoma. The liver is the major organ involved in the regulation of energy homeostasis, and in pathological conditions such as T1DM, changes in liver metabolic pathways result in hyperglycemia, which is associated with multiple organic dysfunctions. In this context, it has been suggested that chlorophyll-a and its derivatives have anti-diabetic actions, such as reducing hyperglycemia, hyperinsulinemia, and hypertriglyceridemia, but these effects have not yet been proven. Thus, the biological action of PDT with chlorophyll-a on hepatic parameters related to energy metabolism and oxidative stress in T1DM Wistar rats was investigated. Evaluation of the acute effects of this pigment was performed by incubation of isolated hepatocytes with chlorophyll-a and the chronic effects were evaluated by oral treatment with chlorophyll-based extract, with post-analysis of the intact liver by in situ perfusion. In both experimental protocols, chlorophyll-a decreased hepatic glucose release and glycogenolysis rate and stimulated the glycolytic pathway in DM/PDT. In addition, there was a reduction in hepatic oxidative stress, noticeable by decreased lipoperoxidation, reactive oxygen species, and carbonylated proteins in livers of chlorophyll-treated T1DM rats. These are indicators of the potential capacity of chlorophyll-a in improving the status of the diabetic liver.

NaCl stress impact on the key enzymes in glycolysis from Lactobacillus bulgaricus during freeze-drying

Abstract The viability of Lactobacillus bulgaricus in freeze-drying is of significant commercial interest to dairy industries. In the study, L.bulgaricus demonstrated a significantly improved (p < 0.05) survival rate during freeze-drying when subjected to a pre-stressed period under the conditions of 2% (w/v) NaCl for 2 h in the late growth phase. The main energy source for the life activity of lactic acid bacteria is related to the glycolytic pathway. To investigate the phenomenon of this stress-related viability improvement in L. bulgaricus, the activities and corresponding genes of key enzymes in glycolysis during 2% NaCl stress were studied. NaCl stress significantly enhanced (p < 0.05) glucose utilization. The activities of glycolytic enzymes (phosphofructokinase, pyruvate kinase, and lactate dehydrogenase) decreased during freeze-drying, and NaCl stress were found to improve activities of these enzymes before and after freeze-drying. However, a transcriptional analysis of the corresponding genes suggested that the effect of NaCl stress on the expression of the pfk2 gene was not obvious. The increased survival of freeze-dried cells of L. bulgaricus under NaCl stress might be due to changes in only the activity or translation level of these enzymes in different environmental conditions but have no relation to their mRNA transcription level.

Obesity Preserves Myocardial Function During Blockade of the Glycolytic Pathway / A Obesidade Preserva a Função do Miocárdio Durante o Bloqueio da Via Glicolítica

Background: Obesity is defined by excessive accumulation of body fat relative to lean tissue. Studies during the last few years indicate that cardiac function in obese animals may be preserved, increased or diminished. Objective: Study the energy balance of the myocardium with the hypothesis that the increase in fatty acid oxidation and reduced glucose leads to cardiac dysfunction in obesity. Methods: 30-day-old male Wistar rats were fed standard and hypercaloric diet for 30 weeks. Cardiac function and morphology were assessed. In this paper was viewed the general characteristics and comorbities associated to obesity. The structure cardiac was determined by weights of the heart and left ventricle (LV). Myocardial function was evaluated by studying isolated papillary muscles from the LV, under the baseline condition and after inotropic and lusitropic maneuvers: myocardial stiffness; postrest contraction; increase in extracellular Ca2+ concentration; change in heart rate and inhibitor of glycolytic pathway. Results: Compared with control group, the obese rats had increased body fat and co-morbities associated with obesity. Functional assessment after blocking iodoacetate shows no difference in the linear regression of DT, however, the RT showed a statistically significant difference in behavior between the control and the obese group, most notable being the slope in group C. Conclusion: The energy imbalance on obesity did not cause cardiac dysfunction. On the contrary, the prioritization of fatty acids utilization provides protection to cardiac muscle during the inhibition of glycolysis, suggesting that this pathway is fewer used by obese cardiac muscle. .

Fundamento: A obesidade é definida por um acúmulo excessivo do tecido adiposo em relação a massa magra tecidual. Estudos realizados nos últimos anos sugerem que a função cardíaca em animais obesos pode se encontrar preservada, aumentada ou reduzida. Objetivo: Estudar o balanço energético do miocárdio com a hipótese de que o aumento na oxidação de ácidos graxos e redução de glicose levam à disfunção cardíaca na obesidade. Métodos: Ratos Wistar machos com 30 dias de idade foram alimentados com uma dieta padrão ou hipercalórica durante 30 semanas. A função e morfologia cardíacas foram analisadas. Neste trabalho foram estudadas as características gerais e comorbidades associadas com a obesidade. A estrutura cardíaca foi determinada pelo peso do coração e do ventrículo esquerdo (VE). A função do miocárdio foi avaliada pela análise de músculos papilares isolados do VE, na condição basal e depois de manobras inotrópicas e lusitrópicas: rigidez do miocárdio, contração pós-pausa, aumento da concentração extracelular de Ca2+, mudança na frequência de estímulos e inibição da via glicolítica. Resultados: Os ratos obesos tiveram um aumento de tecido adiposo e comorbidades associadas à obesidade em relação aos ratos do grupo controle. A análise funcional após o bloqueio pelo iodoacetato não mostrou diferença na regressão linear da tensão desenvolvida (TD), entretanto, a tensão de repouso (TR) apresentou uma diferença estatística significativa entre o grupo controle e o grupo obeso, mais notadamente na inclinação da curva no grupo C. Conclusão: O desequilíbrio energético na obesidade não promoveu ...

Anti-bacterial activity of Achatina CRP and its mechanism of action.

The physiological role of C-reactive protein (CRP), the classical acute-phase protein, is not well documented, despite many reports on biological effects of CRP in vitro and in model systems in vivo. It has been suggested that CRP protects mice against lethal toxicity of bacterial infections by implementing immunological responses. In Achatina fulica CRP is a constitutive multifunctional protein in haemolymph and considered responsible for their survival in the environment for millions of years. The efficacy of Achatina CRP (ACRP) was tested against both Salmonella typhimurium and Bacillus subtilis infections in mice where endogenous CRP level is negligible even after inflammatory stimulus. Further, growth curves of the bacteria revealed that ACRP (50 µg/mL) is bacteriostatic against gram negative salmonellae and bactericidal against gram positive bacilli. ACRP induced energy crises in bacterial cells, inhibited key carbohydrate metabolic enzymes such as phosphofructokinase in glycolysis, isocitrate dehydrogenase in TCA cycle, isocitrate lyase in glyoxylate cycle and fructose-1,6-bisphosphatase in gluconeogenesis. ACRP disturbed the homeostasis of cellular redox potential as well as reduced glutathione status, which is accompanied by an enhanced rate of lipid peroxidation. Annexin V-Cy3/CFDA dual staining clearly showed ACRP induced apoptosis-like death in bacterial cell population. Moreover, immunoblot analyses also indicated apoptosis-like death in ACRP treated bacterial cells, where activation of poly (ADP-ribose) polymerase-1 (PARP) and caspase-3 was noteworthy. It is concluded that metabolic impairment by ACRP in bacterial cells is primarily due to generation of reactive oxygen species and ACRP induced anti-bacterial effect is mediated by metabolic impairment leading to apoptosis-like death in bacterial cells.

Cancer cell metabolism: implications for therapeutic targets

Cancer cell metabolism is characterized by an enhanced uptake and utilization of glucose, a phenomenon known as the Warburg effect. The persistent activation of aerobic glycolysis in cancer cells can be linked to activation of oncogenes or loss of tumor suppressors, thereby fundamentally advancing cancer progression. In this respect, inhibition of glycolytic capacity may contribute to an anticancer effect on malignant cells. Understanding the mechanisms of aerobic glycolysis may present a new basis for cancer treatment. Accordingly, interrupting lactate fermentation and/or other cancer-promoting metabolic sites may provide a promising strategy to halt tumor development. In this review, we will discuss dysregulated and reprogrammed cancer metabolism followed by clinical relevance of the metabolic enzymes, such as hexokinase, phosphofructokinase, pyruvate kinase M2, lactate dehydrogenase, pyruvate dehydrogenase kinase and glutaminase. The proper intervention of these metabolic sites may provide a therapeutic advantage that can help overcome resistance to chemotherapy or radiotherapy.

Metabolic changes induced by pre-administration of L-alanyl-glutamine and Omega-3 in Wistar rats subjected to sepsis / Alterações metabólicas induzidas pela pré-administração de L-alanil-glutamina e ômega-3 em ratos Wistar submetidos à sepse

PURPOSE: To evaluate the metabolic changes induced by pre-administration of L-alanyl-glutamine (L-Ala-Gln) and omega-3 (ω-3) in rats subjected to sepsis. METHODS: Eighteen male Wistar rats were randomized into three groups (n=6) and treated with saline (group Control-G-1), L-Ala-Gln (0.75 mg /kg , G-2) or ω-3 (0.2 g /kg, G-3 ) administered intravenously 3, 2 and 1 day and 30 minutes before induction of sepsis. Samples (blood, striated muscle and liver) were collected 48 hours after induction of sepsis, to measure the concentrations of metabolites (pyruvate, lactate, glucose and ketone bodies. RESULTS: There was a significant increase in muscle glycolysis and gluconeogenesis in the liver in rats treated with L-Ala-Gln and ω-3, compared to the control group, 48 hours after induction of sepsis. CONCLUSION: Pre-administration of L-Ala-Gln or ω-3 to rats subjected to sepsis resulted in similar metabolic changes, by rising glycolysis in peripheral tissues and stimulating hepatic gluconeogenesis and ketogenesis, resulting in increased energy supply to septic rats.

OBJETIVO: Avaliar as alterações metabólicas induzidas pela pré-administração de L-alanil-glutamina (L-Ala-Gln) e ômega-3 (ω-3) em ratos Wistar submetidos à sepse. MÉTODOS: Dezoito ratos machos Wistar, randomizados em três grupos iguais (n=6) e tratados com solução salina (grupo Controle-G-1), L-Ala-Gln (0,75mg/Kg) ou ω-3 (0,2g/Kg) por via endovenosa administrados 3, 2 e 1 dia e 30 minutos antes da indução do estado de sepse. Amostras (sangue, músculo estriado e fígado) foram coletadas 48 horas após indução da sepse, para dosagem das concentrações de metabólitos (piruvato, lactato, glicose e corpos cetônicos). RESULTADOS: Houve aumento significante da glicólise no músculo e da gliconeogênese no fígado nos ratos tratados com L-Ala-Gln e ω-3, comparados ao controle, 48 horas após a indução da sepse. CONCLUSÃO: A pré-administração de L-Ala-Gln ou ω-3 em ratos submetidos à sepse resultou em alterações metabólicas semelhantes, com aumento da glicólise nos tecidos periféricos e da gliconeogênese hepática e cetogênese, aumentando a oferta de energia disponível.

Effectiveness of Sodium Fluoride as a Glycolysis Inhibitor on Blood Glucose Measurement: Comparison of Blood Glucose using Specimens from the Korea National Health and Nutrition Examination Survey / 대한진단검사의학회지

BACKGROUND: Accurate measurement of blood glucose concentrations is essential for defining diabetes, and the minimization of ex vivo glycolysis has been recommended. Recent guidelines advocate two kinds of methods for sample collection and processing: either the sodium fluoride (NaF) method or immediate refrigeration using a serum separation tube (SST). We investigated the difference between the two methods in measuring subsequent glucose concentrations using blood specimens from participants recruited for the fourth Korean National Health and Nutrition Examination Survey. METHODS: Paired venous blood samples were collected in an SST and a NaF tube from 1,103 men and women. SST serum was separated within 30 min, including standing for 15 min, and then refrigerated. The NaF samples were refrigerated, but not separated until immediately before analysis. We compared the blood glucose concentrations between the SST (SST glucose) and NaF (NaF glucose) methods. RESULTS: The mean SST glucose was significantly higher than NaF glucose (99.0 mg/dL vs 96.5 mg/dL, P<0.05). NaF glucose showed a negative mean bias of 2.6 mg/dL vs SST glucose but showed high correlation (R=0.9899). There was no significant correlation between the bias of blood glucose concentrations by two methods and the storage time of NaF glucose. CONCLUSIONS: The negative bias associated with the use of NaF tubes may significantly affect the prevalence of diabetes. Serum separation and refrigeration within 30 min after venous sampling is recommended over NaF method, not only to minimize the preanalytical impact on detecting diabetes but also to reduce sample volume and number of tubes.

Time sequence of changes in the responsiveness of glycogen breakdown to adrenergic agonists in perfused liver of rats with insulin-induced hypoglycemia

The time-course changes of the responsiveness of glycogen breakdown to a- and Beta-adrenergic agonists during insulin-induced hypoglycemia (IIH) were investigated. Blood glucose levels were decreased prior to the alteration in the hepatic responsiveness to adrenergic agonists. The activation of hepatic glucose production and glycogenolysis by phenylephrine (2 µM) and isoproterenol (20 µM) was decreased in IIH. The changes in the responsiveness of glycogen catabolism were first observed for isoproterenol and later for phenylephrine. Hepatic ß-adrenergic receptors showed a higher degree of adrenergic desensitization than did a-receptors. Liver glycogen synthase activity, glycogen content and the catabolic effect of dibutyryl cyclic AMP (the Beta-receptor second messenger) were not affected by IIH.

Influence of Coccinia indica on certain enzymes in glycolytic and lipolytic pathway in human diabetes.

Dried extract of C Indica in doses of 500 mgm/kg body weight were administered orally to 30 diabetic patients for six weeks. Blood samples were collected 15 minutes after administration of 10 IU heparin for estimation of LPL, before and after treatment with C. Indica Non heparinised samples were utilized for estimation for G-6-p (ase), LDH and blood sugar. Severity of disease were assessed by the findings of blood sugar level. Mild diabetes had no effect on LPL, LDH and G-6-P (ase). But, reduced activity of enzyme LPL and raised level of G-6-P (ase) and LDH in plasma of severe diabetics were found to be highly significant (p < 0.001). The alteration in these parameters in untreated diabetics were restored after treatment with C. indica Hence, it can be postulated that the ingredients present in the extract of C. indica, act like insulin, correcting the elevated enzymes G-6-p (ase), LDH in glycolytic pathway and restore the LPL activity in lypolytic pathway with the control of hyperglycemia in diabetes.

Bordetella pertussis extract induces increase in the activities of glycolytic enzymes in mouse liver.

The hypoglycemic effect of Bordetella pertussis (Challenge strain No.18323) purified cell extract (protein with traces of carbohydrates, 2 mg%) administered (0.1 mg/100 g body wt. i.v.) into mice on the activities of the key regulatory enzymes, viz. glucokinase, phosphofructokinase, pyruvate kinase, glyceraldehyde phosphodehydrogenase, glucose-6-phosphate dehydrogenase (G-6-PD) and lactate dehydrogenase, of glycolytic pathway in liver has been studied at varying intervals after injection. The maximum hypoglycaemic effect was observed at the end of 12 hr, while activities of all the enzymes studied showed significant enhancement after 18 hr, thus suggesting increased glucose utilization towards the formation of pyruvate. Actinomycin D is found to inhibit stimulation of G-6-PD activity in B. pertussis treated animals, thereby indicating the role of B. pertussis in synthesis of this enzyme.

Protection to glycolysis by a combination of 5-hydroxy-L-tryptophan and 2-aminoethylisothiuronium bromide hydrobromide in lethally irradiated rats.

Rate of glycolysis in vivo at different time intervals following 8 Gy [LD100(30)] whole body gamma radiation (WBGR) was evaluated by estimating liver glycogen, blood sugar, serum lactic dehydrogenase (LDH) and blood lactic acid concentration in adult male Sprague Dawley rats. Within 1 hr of radiation exposure, a significant fall in liver glycogen was observed in rats fed food and water ad libitum. The glycogen content increased after 24 hr and had returned to control level on 7th day after radiation exposure. Blood sugar, serum LDH and blood lactate levels increased significantly as compared to non irradiated controls. Pretreatment with 5-hydroxy-L-tryptophan (5-HTP; 100 mg/kg) + 2-aminoethylisothiuronium bromide hydrobromide (AET; 20 mg/kg) ip 30 min before 8 Gy WBGR, modified these values and restored them to normal level on 7th day post-irradiation.

Effect of antiandrogens on some key enzymes of glycolysis in epididymis and ventral prostate of rat.

Effect of three antiandrogens: cyproterone acetate (5 mg/day, sc), flutamide (5 mg/day, sc) and STS-557 (5 mg/day, po) and an estrogen, estradiol dipropionate (5 micrograms/day, sc) on some key enzymes of carbohydrate metabolism was investigated in adult rat epididymis and ventral prostate. Antiandrogens were administered for 21 days and estrogen for 14 days. All of them caused a significant decrease in the weight of epididymis, seminal vesicles and ventral prostate. A significant decrease in the specific activities of enzymes (hexokinase, phosphofructokinase, aldolase, glyceraldehyde phosphate dehydrogenase, pyruvate kinase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase) occurred only in the organs of estrogen treated rats; activities of some of the enzymes were lowered also in the prostate of STS-557 treated rats. Flutamide and cyproterone acetate were ineffective in this regard. The possible factors responsible for the ineffectiveness of synthetic antiandrogens in influencing epididymal metabolism are discussed.

Effect of selected metal ions on the motility and carbohydrate metabolism of ejaculated human spermatozoa.

Zinc, lead and cadmium in the form of chloride salts when added to a standard assay system containing 80 X 10(-6) ejaculated washed human spermatozoa caused a dose and duration-dependent inhibition of their motility. The activity of certain key enzymes of carbohydrate and energy metabolism, viz, glycogen phosphorylase, glucose-6-phosphatase, fructose-1, 6-diphosphatase, glucose-6-phosphate isomerase, amylase, Mg2+- dependent ATPase and lactic and succinic acid dehydrogenases were also found to be inhibited. The order of inhibitory effects of the heavy metals were zinc less than lead less than cadmium. The metal chelating agent, ethylene diamine tetra-acetic acid (EDTA, disodium salt) also interfered with the spermatozoal motility and inhibited the enzyme activities.