Sodium butyrate aggravates glucose dysregulation and dyslipidemia in high fat-fed Wistar rats.

Sodium butyrate (NaB), a short chain fatty acid (SCFA) has been shown to improve metabolic, glucose and lipid signaling. High fat diet elicits increased risk of cardiometabolic disease due to dysmetabolism, altered endothelial function and elevated oxidant activities. This study aims at evaluating the effect of NaB on high fat diet-fed female Wistar rats, and the possible role of vascular endothelial growth factor (VEGF). Twenty female Wistar rats with mean weight of 120 ± 5 g were divided randomly after one week of acclimatization into four groups: Control diet (CTR), High fat diet (HFD), NaB (200 mg/kg), and HFD + NaB. After six weeks of the experimental procedure, blood samples were collected by cardiac puncture. Data were analyzed and expressed in mean ± SEM and p-values <0.05 were accepted as significant. Data showed that HFD increased lactate dehydrogenase (LD) and free fatty acid (FFA), but not triglyceride (TG) and total cholesterol (TC). It also led to insulin resistance (elevated fasting blood glucose, insulin and homeostasis model assessment for insulin resistance). These effects of HFD were accompanied by increased lipid peroxidation (malondialdehyde and 4-hydroxynonenal). Sodium butyrate significantly decreased circulating nitric oxide (NO) and LD while increasing FFA, TG, insulin resistance, aggravated lipid peroxidation and increased VEGF in HFD rats (P < 0.05). We speculated therefore, that NaB aggravated glucose dysregulation and dyslipidemia, which is accompanied by increased VEGF.

Temporal bone pneumatization: A scoping review on the growth and size of mastoid air cell system with age.

The interest in the mastoid air cell system arose from the association between temporal bone aeration and otitis media. Its size and growth have been considered when planning chronic and middle ear surgeries. The objective of this review was to explore the literature on the size of mastoid air cells with age, highlighting various growth rates reported and mapping out areas yet to be fully understood for further research. A three-step systematic search was conducted for available literature on the subject matter viz; Google Scholar, Medline, Cochrane Library, and PubMed. Eligibility criteria guided the study selection, and eligible studies were subjected to appraisal using screening and quantitative criteria of mixed-method appraisal tool. A data extraction form was developed to extract information from eligible studies. Nine studies met the eligibility criteria. 55.6% of the included studies were conducted among the east and south Asian population, 33.3% were conducted among Scandinavians, and 11.1% in South America. Age groupings varied among studies; 33.3% utilized 1-year age grouping, 33.3% utilized 5-year age grouping, 11.1% utilized 10-year age grouping. In reporting the size of mastoid air cells across age groupings, 66.7% utilized area, 22.2% utilized volume, while 11.1% utilized both area and volume. Findings from this review showed that the mastoid air cells' size with respect to age differs among populations of different origins. The most common measurements were the area of air cells. The highest growth rate was reported up to 30 years. Findings also show the influence of sex on the size of mastoid air cells and growth rate with age, as females were reported to have larger air cells with rapid growth until puberty. However, the male mastoid air cell system continues a steady growth after puberty and becomes larger. Information still lacks in the volume of air cells in pediatric pneumatization.

Melatonin ameliorates endocrine dysfunction and defective sperm integrity associated with high-fat diet-induced obesity in male Wistar rats.

Obesity (OBS) has been established as a link to male hypogonadism with consequent infertility. Previous studies have shown that melatonin (MEL) modulates hypothalamic-pituitary-gonadal function. The present study therefore investigated the hypothesis that MEL supplementation would attenuate spermatogenic and steroidogenic dysfunctions associated with obesity induced by high-fat diet (HFD). Twenty-four adult male Wistar rats (n = 6/group) were used: control group received vehicle (normal saline), obese group received 40% high-fat diet and distilled water, MEL-treated group received MEL (4 mg/kg), and OBS + MEL group received MEL and 40% HFD and the treatment lasted for 12 weeks. HFD caused increased body weight, glucose intolerance, plasma triglyceride and low-density lipoprotein cholesterol/ very low-density lipoprotein cholesterol and malondialdehyde, as well as decreased antioxidant capacity, high-density lipoprotein cholesterol, gonadotrophin-releasing hormone, follicle-stimulating hormone and testosterone and altered sperm parameters. However, all these alterations were attenuated when supplemented with MEL. Taken together, these results indicate that HFD exposure causes endocrine dysfunction and disrupted sperm parameters in obese animals, which are accompanied by lipid peroxidation/defective antioxidant capacity. In addition, the present results suggest that melatonin supplementation restores endocrine function and sperm integrity in obese rat model by suppression of oxidative stress-dependent mechanism.

Acetate rescues defective brain-adipose metabolic network in obese Wistar rats by modulation of peroxisome proliferator-activated receptor-γ.

We investigated the hypothesis that acetate ameliorates brain-adipose metabolic dysfunction (BAMED) in high fat diet (HFD)-induced obesity, possibly by modulation of peroxisome proliferator-activated receptor-γ (PPAR-γ). Ten-week-old male Wistar rats were randomly assigned into four groups (n = 6/group): Control, acetate and obese with or without acetate groups received vehicle (distilled water; po), acetate (200 mg/kg, po) and 40% HFD with or without acetate respectively. The treatments lasted for 12 weeks. Obese animals showed increase in body weight, visceral fat mass, insulin and triglyceride-glucose index and a reduction in insulin sensitivity. In addition, obese animals also showed increase in plasma/hypothalamic and adipose pyruvate dehydrogenase kinase-4, lactate-pyruvate ratio, malondialdehyde, γ-glutamyl transferase, and a decrease in glucose-6-phosphate dehydrogenase, glutathione, nitric oxide and PPAR-γ. HFD also elevated plasma/hypothalamic lipid and decreased adipose lipid profile, increased hypothalamic and adipose tumor necrosis factor-α, interleukin-6 and histone deacetylase (HDAC), and elevated plasma/adipose leptin. These alterations were reversed by concomitant administration of acetate. The present results demonstrate that obesity is characterized by BAMED, which is accompanied by altered HDAC/PPAR-γ. The results in addition suggest that acetate, an HDAC inhibitor rescues BAMED with consequent normalization of body weight and visceral fat mass by modulation of PPAR-γ and suppression of oxidative stress.

Oral L-glutamine restores adenosine and glutathione content in the skeletal muscle and adipose tissue of insulin-resistant pregnant rats.

OBJECTIVES: Mishandling of lipid and glycogen has been documented as a feature of metabolic tissues in insulin resistance-related disorders. However, reports exist detailing that L-glutamine (GLN) protects non-adipose tissue against the deleterious effects of metabolic disorders. Therefore, we hypothesized that GLN would protect skeletal muscle and adipose tissue against the deleterious effects of lipid and glycogen mishandlings by increasing adenosine and glutathione levels in pregnant rats exposed to fructose (FRU)-enriched drinks. METHODS: Pregnant Wistar rats weighing 150 to 180 g were randomly assigned to control, GLN, FRU, and FRU + GLN groups (six rats/group). The groups received vehicle (P.o.), glutamine (1 g/kg), FRU (10%; w/v), and FRU + GLN, respectively, for 19 d. RESULTS: Data show that FRU caused insulin resistance with corresponding increased blood glucose, circulating and pancreatic insulin levels, and lipid accumulation and glycogen depletion in skeletal muscle, but glycogen accumulation and a decreased lipid profile in adipose tissue. Adenosine and glutathione content decreased, whereas adenosine deaminase, xanthine oxidase, uric acid, and malondialdehyde concentrations increased in both tissues. In addition, glucose-6-phosphate dehydrogenase activity decreased in skeletal muscle but remained unaltered in adipose tissue. However, supplementation with GLN improved perturbed lipid and glycogen with a corresponding increase in adenosine and glutathione. CONCLUSIONS: The present results collectively indicate that lipid and glycogen mishandlings caused by high gestational FRU intake result in the depletion of adenosine and glutathione in skeletal muscle and adipose tissue. These findings also suggest that L-glutamine protects against skeletal muscle and adipose tissue dysmetabolism by enhancing adenosine and glutathione.

L-glutamine ameliorates adipose-hepatic dysmetabolism in OC-treated female rats.

Adipose dysfunction and inflammation with or without hepatic defects underlie metabolic obesity. Glutamine (GLU) improves glucoregulation and metabolic indices but its effects on adipose function and hepatic lipid deposition in estrogen-progestin oral contraceptive (EPOC) users are unknown. Therefore, we hypothesized that GLUT supplementation would protect against adipose dysfunction and excess hepatic lipid influx and deposition in EPOC-treated animals by suppressing adenosine deaminase/xanthine oxidase (ADA/XO) activity and improving glucose-6-phosphate dehydrogenase (G6PD)-dependent antioxidant defense. Female Wistar rats weighing 150-180 g were allotted into control, GLUT, EPOC and EPOC + GLUT groups (six rats/group). The groups received vehicle (distilled water, p.o.), GLUT (1 g/kg), EPOC containing 1.0 µg ethinylestradiol plus 5.0 µg levonorgestrel and EPOC plus GLUT, respectively, daily for 8 weeks. Results showed that the administration of EPOC caused glucose dysregulation and increased triglyceride-glucose index and visceral adiposity, but the body weight and liver weight were not affected. However, EPOC significantly decreased adipose lipid, G6PD and glutathione and increased glycogen synthesis, ADA, XO, uric acid, lipid peroxidation, lactate production and gamma-glutamyl transferase activity (GGT). On the other hand, EPOC increased hepatic lipid, ADA, XO, uric acid, lipid peroxidation and lactate production and decreased glycogen synthesis, G6PD and glutathione. Nevertheless, supplementation with glutamine attenuated these alterations. Collectively, the present results indicate that EPOC causes metabolically induced obesity which is associated with adipose dysfunction and hepatic metabolic disturbance. The findings also suggest that glutamine confers metabo-protection with corresponding improvement in adipose and hepatic metabolic function by suppression of ADA/XO activity and enhancement of G6PD-dependent antioxidant defense.

Oral L-glutamine rescues fructose-induced poor fetal outcome by preventing placental triglyceride and uric acid accumulation in Wistar rats.

BACKGROUND: Metabolic adaptation of pregnant mothers is crucial for placental development and fetal growth/survival. However, evidence exists that indiscriminate consumption of fructose-enriched drink (FED) during pregnancy disrupts maternal-fetal metabolic tolerance with attendant adverse fetal outcomes. Glutamine supplementation (GLN) has been shown to exert a modulatory effect in metabolic disorders. Nevertheless, the effects of GLN on FED-induced poor fetal outcome, and in particular the impacts on placental uric acid/lipid accumulation are unknown. The present study was conducted to test the hypothesis that oral GLN improves fetal outcome by attenuating placental lipid accumulation and uric acid synthesis in pregnant rats exposed to FED. MATERIALS AND METHODS: Pregnant Wistar rats (160-180 g) were randomly allotted to control, GLN, FED and FED + GLN groups (6 rats/group). The groups received vehicle by oral gavage, glutamine (1 g/kg) by oral gavage, fructose (10%; w/v) and fructose + glutamine, respectively, through gestation. RESULTS: Data showed that FED during pregnancy caused placental inefficiency, reduced fetal growth, and caused insulin resistance with correspondent increase in fasting blood glucose and plasma insulin. FED also resulted in an increased placental triglyceride, total cholesterol and de novo uric acid synthesis by activating adenosine deaminase and xanthine oxidase activities. Moreover, FED during pregnancy led to increased lipid peroxidation, lactate production with correspondent decreased adenosine and glucose-6-phosphate dehydrogenase-dependent antioxidant defense. These alterations were abrogated by GLN supplementation. CONCLUSION: These findings implicate that high FED intake during pregnancy causes poor fetal outcome via defective placental uric acid/triglyceride-dependent mechanism. The findings also suggest that oral GLN improves fetal outcome by ameliorating placental defects through suppression of uric acid/triglyceride accumulation.

l-glutamine supplementation exerts cardio-renal protection in estrogen-progestin oral contraceptive-treated female rats.

Glycogen and lipid disruptions represent a spectrum of metabolic disorders that are crucial risk factors for cardiovascular disease in estrogen-progestin oral contraceptive (COC) users. l-glutamine (GLN) has been shown to exert a modulatory effect in metabolic disorders-related syndromes. We therefore hypothesized that GLN supplementation would protect against myocardial and renal glycogen-lipid mishandling in COC-treated animals by modulation of Glucose-6-phosphate dehydrogenase (G6PD) and xanthine oxidase (XO) activities. Adult female Wistar rats were randomly allotted into control, GLN, COC and COC + GLN groups (six rats per group). The groups received vehicle (distilled water, p.o.), GLN (1 g/kg), COC containing 1.0 µg ethinylestradiol plus 5.0 µg levonorgestrel and COC plus GLN respectively, daily for 8 weeks. Data showed that treatment with COC led to metabolically-induced obesity with correspondent increased visceral and epicardial fat mass. It also led to increased plasma, myocardial and renal triglyceride, free fatty acid, malondialdehyde (MDA), XO activity, uric acid content and decreased glutathione content and G6PD activity. In addition, COC increased myocardial but not renal glycogen content, and increased myocardial and renal glycogen synthase activity, increased plasma and renal lactate production and plasma aspartate transaminase/alanine aminotransferase (AST/ALT) ratio. However, these alterations were attenuated when supplemented with GLN except plasma AST/ALT ratio. Collectively, the present results indicate that estrogen-progestin oral contraceptive causes metabolically-induced obesity that is accompanied by differential myocardial and renal metabolic disturbances. The findings also suggest that irrespective of varying metabolic phenotypes, GLN exerts protection against cardio-renal dysmetabolism by modulation of XO and G6PD activities.

Oral ethinylestradiol-levonorgestrel normalizes fructose-induced hepatic lipid accumulation and glycogen depletion in female rats.

The present study investigated the effects of oral ethinylestradiol-levonorgestrel (EEL) on hepatic lipid and glycogen contents during high fructose (HF) intake, and determined whether pyruvate dehydrogenase kinase-4 (PDK-4) and glucose-6-phosphate dehydrogenase (G6PD) activity were involved in HF and (or) EEL-induced hepatic dysmetabolism. Female Wistar rats weighing 140-160 g were divided into groups. The control, EEL, HF, and EEL+HF groups received water (vehicle, p.o.), 1.0 µg ethinylestradiol plus 5.0 µg levonorgestrel (p.o.), fructose (10% w/v), and EEL plus HF, respectively, on a daily basis for 8 weeks. Results revealed that treatment with EEL or HF led to insulin resistance, hyperinsulinemia, increased hepatic uric acid production and triglyceride content, reduced glycogen content, and reduced production of plasma or hepatic glutathione- and G6PD-dependent antioxidants. HF but not EEL also increased fasting glucose and hepatic PDK-4. Nonetheless, these alterations were attenuated by EEL in HF-treated rats. Our results demonstrate that hepatic lipid accumulation and glycogen depletion induced by HF is accompanied by increased PDK-4 and defective G6PD activity. The findings also suggest that EEL would attenuate hepatic lipid accumulation and glycogen depletion by suppression of PDK-4 and enhancement of a G6PD-dependent antioxidant barrier.

Glutamine confers renoprotection by normalizing lipid and glutathione content in insulin-resistant pregnant rats.

OBJECTIVE: Increasing consumption of fructose is a major contributor to epidemic metabolic syndrome (MS), and the risk of renal disorders and/or injuries remains high among individuals with MS particularly during pregnancy. Glutamine (GLT) has been demonstrated to have a modulatory effect in MS and/or insulin resistance (IR). This study investigated the effect of GLT on renal lipid accumulation and glutathione depletion induced by high fructose-enriched drink (FED) in pregnant rats and also tested the hypothesis that the renoprotective role of GLT is by suppression of adenosine deaminase (ADA)/xanthine oxidase (XO)/uric acid (UA) pathway. METHODS: Pregnant Wistar rats weighing between 160 and 180 g were allotted into Control, GLT, FED and FED + GLT groups (6 rats/group). The groups received distilled water (vehicle, p. o.), 1 g/kg bw GLT (p.o.), 10% Fructose (w/v) and 10% Fructose (w/v) plus 1 g/kg bw GLT (p.o.) respectively, daily for 19 days. RESULTS: Data showed that FED caused IR, increased body weight gain, blood glucose, plasma insulin, creatinine, urea, lipid accumulation, lipid peroxidation, lactate production, aspartate transaminase and alanine aminotransferase, depressed Glucose-6-phosphate dehydrogenase, sodium-potassium-ATPase activities and glutathione. These alterations were accompanied by increased activity of ADA/XO/UA pathway. However, the FED-induced renal injury and its correlates were normalized by GLT supplementation. CONCLUSION: The present results demonstrate that renal lipid accumulation and glutathione depletion-driven renal injury in pregnant rats is accompanied by increased activity of ADA/XO/UA pathway. The findings also suggest that GLT would confer protection against renal injury by protecting against lipid accumulation and glutathionedepletion, at least in part, through suppression of ADA/XO/UA pathway.

Preventive effects of l-glutamine on gestational fructose-induced cardiac hypertrophy: involvement of pyruvate dehydrogenase kinase-4.

Gestational fructose exposure has detrimental health consequences on both the maternal and fetus or offspring in the early or later life, contributing to epidemic rise in cardiometabolic syndrome including cardiac events. l-Glutamine has been shown to mitigate cardiac metabolic stress. However, the effect of l-glutamine on cardiac hypertrophy induced by gestational fructose exposure is not known. We therefore hypothesized that l-glutamine would prevent gestational fructose-induced cardiac hypertrophy, possibly by suppression of pyruvate dehydrogenase kinase-4 (PDK-4). Pregnant Wistar rats were allotted into the control, l-glutamine, gestational fructose exposure, and gestational fructose exposure plus l-glutamine groups (6 rats in each group). The groups received distilled water (vehicle, per os), 1 g/kg body weight l-glutamine (per os), 10% fructose (w/v) and 10% fructose (w/v) plus 1 g/kg l-glutamine (per os), respectively, daily for 19 days. Data from this study showed that gestational fructose-enriched drink caused cardiac hypertrophy with correspondent body weight gain, glucose dysregulation, increased cardiac PDK-4, triglyceride, glycogen, lactate, and uric acid production. On the other hand, defective glutathione-dependent antioxidant barrier was also observed in pregnant rats taking fructose-enriched drink. However, the gestational fructose-induced cardiac hypertrophy and its correlates were attenuated by l-glutamine. The present results demonstrate that gestational fructose-enriched drink induces cardiac hypertrophy that is accompanied by increased PDK-4. The findings also suggest that the inhibitory effect of l-glutamine on PDK-4 prevents the development of cardiac hypertrophy, thereby implying that PDK-4 may be a potential novel therapeutic intervention for cardiac hypertrophy especially in pregnancy.

Oral ethinylestradiol-levonorgestrel attenuates cardiac glycogen and triglyceride accumulation in high fructose female rats by suppressing pyruvate dehydrogenase kinase-4.

Fructose (FRU) intake has increased dramatically in recent decades with a corresponding increased incidence of insulin resistance (IR), particularly in young adults. The use of oral ethinylestradiol-levonorgestrel (EEL) formulation is also common among young women worldwide. The present study aimed at determining the effect of EEL on high fructose-induced cardiac triglyceride (TG) and glycogen accumulation. The study also investigated the possible involvement of pyruvate dehydrogenase kinase-4 (PDK-4) in EEL and/or high fructose metabolic effects on the heart. Ten-week-old female Wistar rats were allotted into four groups. The control, EEL, FRU, and EEL + FRU rats received distilled water (vehicle, p.o.), 1.0 µg ethinylestradiol plus 5.0 µg levonorgestrel (p.o.), 10% fructose (w/v), and 1.0 µg ethinylestradiol plus 5.0 µg levonorgestrel and 10% fructose, respectively, daily for 8 weeks. Data showed that EEL or high fructose caused IR' impaired glucose tolerance' hyperlipidemia' increased plasma lactate, lactate dehydrogenase, PDK-4, uric acid, xanthine oxidase (XO), adenosine deaminase (ADA), malondialdehyde (MDA), cardiac uric acid, TG, TG/HDL- cholesterol, glycogen synthesis, MDA, and visceral fat content and reduced glutathione. High fructose also resulted in impaired pancreatic ß-cell function, hyperglycemia, and increased cardiac PDK-4, lactate synthesis, and mass. Nonetheless, these alterations were ameliorated in EEL plus high fructose rats. This study demonstrates that high fructose-induced myocardial TG and glycogen accumulation is attributable to increased PDK-4. Besides, EEL could be a useful pharmacological utility for protection against cardiac dysmetabolism by inhibiting PDK-4.

Inhibition of pyruvate dehydrogenase kinase-4 by l-glutamine protects pregnant rats against fructose-induced obesity and hepatic lipid accumulation.

OBJECTIVE: Accumulation of lipids in non-adipose tissues particularly the liver is a feature of tissue insulin resistance. Hepatic glycogen depletion reflects counter glucoregulation in an insulin-resistant state and/or obesity. The effect of l-glutamine on fructose-induced increased hepatic lipid accumulation and depleted glycogen content, particularly in pregnancy, is not known. We therefore aimed at investigating the effect of glutamine on fructose-induced weight gain, hepatic lipids and glycogen contents in pregnant rats and also tested the hypothesis that hepatoprotective role of l-glutamine is through suppression of PDK-4. METHODS: Eleven-week-old pregnant Wistar rats were allotted into the Control, Glutamine, Fructose and Fructose plus Glutamine groups (6 rats/group). The groups received distilled water (vehicle, p.o.), 1 g/kg bwl-glutamine (p.o.), 10% Fructose (w/v) and 10% Fructose (w/v) plus 1 g/kg bwl-glutamine (p.o.) respectively, daily for 19 days. Biochemical analysis and histology of the liver were performed. RESULTS: Data showed that fructose intake caused insulin resistance, hyperglycemia, hyperlipidemia, increased body weight gain, visceral fat mass, hepatic mass, lactate production, uric acid production, lipid peroxidation and decreased pancreatic ß-cell function and hepatic glycogen synthesis. These alterations were accompanied by elevated pyruvate dehydrogenase kinase-4 (PDK-4). However, the fructose-induced dysmetabolism were improved by l-glutamine. CONCLUSION: Our results demonstrate that obesity and hepatic lipid accumulation induced by fructose in pregnant rats is accompanied by increased PDK-4. The findings also suggest that l-glutamine would protect against obesity and hepatic lipid accumulation by suppression of PDK-4.