Cymbopogon citratus and Citral Overcome Doxorubicin Resistance in Cancer Cells via Modulating the Drug's Metabolism, Toxicity, and Multidrug Transporters.

Multidrug resistance (MDR) is the major complex mechanism that causes the failure of chemotherapy, especially with drugs of natural origin such as doxorubicin (DOX). Intracellular drug accumulation and detoxification are also involved in cancer resistance by reducing the susceptibility of cancer cells to death. This research aims to identify the volatile composition of Cymbopogon citratus (lemon grass; LG) essential oil and compare the ability of LG and its major compound, citral, to modulate MDR in resistant cell lines. The composition of LG essential oil was identified using gas chromatography mass spectrometry (GC-MS). In addition, a comparison of the modulatory effects of LG and citral, performed on breast (MCF-7/ADR), hepatic (HepG-2/ADR), and ovarian (SKOV-3/ADR) MDR cell lines, were compared to their parent sensitive cells using the MTT assay, ABC transporter function assays, and RT-PCR. Oxygenated monoterpenes (53.69%), sesquiterpene hydrocarbons (19.19%), and oxygenated sesquiterpenes (13.79%) made up the yield of LG essential oil. α-citral (18.50%), ß-citral (10.15%), geranyl acetate (9.65%), ylangene (5.70), δ-elemene (5.38%), and eugenol (4.77) represent the major constituents of LG oil. LG and citral (20 µg/mL) synergistically increased DOX cytotoxicity and lowered DOX dosage by >3-fold and >1.5-fold, respectively. These combinations showed synergism in the isobologram and CI < 1. DOX accumulation or reversal experiment confirmed that LG and citral modulated the efflux pump function. Both substances significantly increased DOX accumulation in resistant cells compared to untreated cells and verapamil (the positive control). RT-PCR confirmed that LG and citral targeted metabolic molecules in resistant cells and significantly downregulated PXR, CYP3A4, GST, MDR1, MRP1, and PCRP genes. Our results suggest a novel dietary and therapeutic strategy combining LG and citral with DOX to overcome multidrug resistance in cancer cells. However, these results should be confirmed by additional animal experiments before being used in human clinical trials.

The Association between Vitamin D Hypovitaminosis and Cardiovascular Disease Risk in Saudi Diabetic Patients Type II.

We evaluated the prevalence and association of Vitamin D deficiency with glycemic control and CVD risk in T2DM patients. Serum 25 (OH)D3, lipid profile, glucose panel, HbA1c, serum insulin, and HOMA-IR were assessed in 93 T2DM patients and 69 controls. 10 years and lifetime ASCVD risk scores were calculated. The levels of 25(OH)D3 were significantly low in T2DM patients compared to the control. T2DM patients with hypovitaminosis D displayed significantly increased FBG, insulin, and HOMA-IR compared to normovitaminosis. Their lifetime and 10-year ASCVD risk scores were significantly higher regardless of vitamin D deficiency levels (P=0.006; P=0.023) in comparison to patients with sufficient levels of vitamin D. Among patients, the lifetime and 10 years of ASCVD risk showed a significant negative correlation with serum 25(OH)D3 and HDLc (P=0.037; 0.018) (P=0.0001), respectively, and significant positive correlation with T2DM duration, serum insulin, and HOMA-IR (P=0.018; 0.0001) (P=0.002; 0.001) (P=0.005; 0.001), respectively. The 10-year ASCVD risk exhibited a significant positive correlation with FBG (P=0.003) and HbA1c (P=0.009). T2DM duration was a predictor of vitamin D deficiency among T2DM patients (ß = 0.22; CI = 0.002-0.04). There is a considerable association between lifetime and 10 years of ASCVD risk with hypovitaminosis D in T2DM, regardless of the deficiency levels which could be predicted by the diabetes duration.

Serum Ferritin and its Importance for SARS-CoV-2-Infected Patients.

BACKGROUND: Serum ferritin is an acute-phase protein whose level is increased in several inflammatory diseases. This review describes the structure and function of ferritin as well as its association with the prognosis of patients with COVID-19. METHODS: We searched MEDLINE/PubMed databases, Scopus, and Web of Science for prospective and review articles that examined ferritin and its association with COVID-19 severity. Based on all these articles and clinical experience, a review was constructed and full texts of the articles that were retrieved were accessed. RESULTS: All COVID-19 related studies conducted in 2020, which performed serum ferritin testing, clearly showed ferritin as a biomarker of COVID-19 severity in hospitalized patients. Ferritin levels in severe patients were significantly increased relative to those in non-severe patients (p < 0.001). Non-survivors had significantly higher ferritin levels than the survivors (p < 0.001). CONCLUSIONS: Determination of ferritin levels was specific and sensitive for early disease severity prediction in patients with COVID-19. Serum ferritin can also be used for predicting the response to COVID-19 vaccines.

Association of TNF-α-308 (G >A) (rs1800629) Gene Polymorphism with Adverse Outcomes of Sepsis in Critically Ill Patients.

Sepsis-related mortality and morbidity are major health care problems worldwide. More effort is required to identify factors associated with adverse outcome. Evaluate the prognostic capacity of tumor necrosis factor (TNF), kidney injury molecule (KIM), and lactate and TNF-α-308 G > A gene polymorphism for prediction of 28 days-intensive care unit (ICU) mortality. TNF-α-308 G > A single nucleotide polymorphisms was detected by real-time-PCR on 112 had septic shock and 88 were septic. Serum TNF-α and urinary KIM were assessed by enzyme-linked immunosorbent assay. This study included 200 critically ill patients, 125 (62.5%) of them died within 28 days in ICU (nonsurvivors). Frequencies of TNF-308 G > A was (70.7) GG, (28) GA and (1.3) AA in survivors versus (85.6) GG, (12) GA and (2.4) AA for nonsurvivors, revealed significant association with ICU mortality but not sepsis severity (p = 0.15) or sepsis-induced acute kidney injury (AKI). In contrast, urinary KIM-1 revealed significant association with sepsis severity (p = 0.036) and AKI (p = 0.0001), but not 28-days ICU mortality. The relative risk of death in patients with GG genotype was 2.5 mainly in ICU younger male patients (odds ratios 24 and 4.9, p = 0.001). The genotype GG and GA were significantly associated with [increased urinary KIM-1 (0.29 ± 0.1) (p = 0.0001), terminal creatinine (1.67 ± 0.8) (p = 0.0001)] and [increased terminal urea (109 ± 0.001) (p = 0.001) and basal serum TNF (60 ± 0.001) (p = 0.0001)], respectively. In linear regression analysis, AKI 0.0001 (0.4-0.67), basal serum TNF 0.04 (0.0001-0.04), and TNF-308 GG 0.007 (0.05-0.33) were associated with 28 days ICU mortality [p value (95% confidence interval)]. The same results were observed for initial urea 0.024 (0.0001-0.003) and lack of diuretic usage 0.0001 (0.35-0.7) mainly in septic patients. Major frequency of TNF-308 G > A polymorphism (mainly in young age male patients), AKI and serum TNF were associated with increased risk for 28 days-ICU mortality. Furthermore, sepsis severity was influenced by TNF and urinary KIM-1, which reflects in AKI.

Evaluation of the Diagnostic and Predicative Values of 8-Iso-Prostaglandin F2α as a Biomarker of Breast Cancer.

BACKGROUND: Breast cancer (BC) is a commonly reported cancer that is widely prevalent among women. Its early detection improves patient survival and results in better outcomes. For diagnosis and follow-up care, tumor markers are one of the feasible investigations to be ordered. 8-Iso-prostaglandin F2α (8-iso-PGF2α) serves as a serum marker reflecting oxidative stress and subsequent damaging of DNA. In the present study, we aimed to evaluate both diagnostic and predictive values of 8-iso-PGF2α in BC patients. MATERIALS AND METHODS: Serum levels of 8-iso-PGF2α were assessed for 66 women with benign breast tumors and 65 women who had malignant BC. To compare the patients who had breast tumors with healthy individuals, 63 women free of breast diseases were selected as controls. RESULTS: The serum level of 8-iso-PGF2α in the BC patients (57.92 pg/mL) was significantly higher compared to those with benign tumors (18.89 pg/mL) (p < 0.001). In addition, individuals with no breast diseases had less 8-iso-PGF2α (4.02 pg/mL) compared to those who had developed a tumor (p < 0.001). Serum 8-iso-PGF2α was found to be positively correlated with both carcinoembryonic antigen (r = 0.74, p < 0.001) and cancer antigen 15-3 (r = 0.80, p < 0.001). Furthermore, serum 8-iso-PGF2α showed high diagnostic performance in BC (AUC = 0.999, sensitivity = 100%, specificity = 99.2% at a cutoff value of 36.18 pg/mL). CONCLUSIONS: Our study found that the high level of serum 8-iso-PGF2α helps to provide a non-invasive indicator to detect BC. Future work with a larger sample size and various phases of BC can confirm the current results which provide insights into the early detection of cancer.

Assessment of tumor necrosis factor alpha polymorphism TNF-α-238 (rs 361525) as a risk factor for development of acute kidney injury in critically ill patients.

Critically ill patients revealed significant adverse outcomes (sepsis, septic shock, organ dysfunction/failure, and mortality) despite variable effort. AIM: this study evaluated the association of TNF-a-238 (rs 361525) with adverse outcomes in critically ill patients. TNF-α-238 (rs 361525) SNP was performed by RT-PCR on 200 critically-ill patients (112 had severe sepsis and septic shock and 88 were septic), 127 of them had AKI. Urinary N-acetyl-ß-(D)-glucosaminidase and serum creatinine were assessed by modified Jaffé and ELISA respectively. These results revealed that heterozygous genotype GA of TNF-α-238 (rs 361525) SNP significantly increased the risk of adverse-outcome (mortality rate) (P = 0.0001; OR 8.9), regardless of organ dysfunction (P = 0.09) or severity of sepsis (P = 0.6). Moreover, heterozygous genotype GA of TNF-α-238 (rs 361525) SNP was significantly associated with inflammatory marker (sTNF-α) (P = 0.014) and tubular injury marker (uNAG) (P = 0.001) that displayed a significant association with severity of sepsis (0.001, 0.035) and organ dysfunction (0.012, 0.0001) respectively. In critically ill patients with sepsis induced AKI, serum TNF-α and uNAG measured at admission can predict severity of sepsis and AKI (defined by REFILE) occurrence along with pre-existing CKD and DM. However, TNF-238 yielded additional prognostic information on ICU mortality irrelevant to AKI in septic patients.

Correction to: Assessment of tumor necrosis factor alpha polymorphism TNF-α-238 (rs 361525) as a risk factor for development of acute kidney injury in critically ill patients.

The title of the original article has been corrected to: Assessment of tumor necrosis factor alpha polymorphism TNF-α-238 (rs 361525) as a risk factor for development of acute kidney injury in critically ill patients. The original article has been corrected to reflect the correct title.

Testosterone, obesity, and waist circumference as determinants of metabolic syndrome in Saudi women.

BACKGROUND: High serum total testosterone is associated with metabolic syndrome (MS). This study aimed to identify possible alterations in total testosterone and their relationship with plasma glucose, blood pressure, and serum lipid profile. METHODS: One hundred forty-two female subjects were selected to participate in this study, and they were recruited by consultant physicians from the Clinic and Medical Out-Patient, King Abdulaziz Hospital, Kingdom of Saudi Arabia. The anthropometric characteristics were obtained from questionnaires by using standard methods. Blood samples were obtained for the determination of glucose, triglycerides, total cholesterol, low-density lipoprotein, and high-density lipoprotein by using enzymatic methods. Total testosterone was determined by enzyme-linked immunosorbent assay for the quantitative measurement of testosterone in human serum. RESULTS: Significantly higher concentrations of total testosterone, low-density lipoprotein, and glucose, but lower concentrations of high-density lipoprotein, were observed in subjects with MS compared with women without MS (P<0.05). CONCLUSION: This study suggests that high levels of total testosterone and disturbance in lipid profile were associated with MS in Saudi women.

Potential Cardiovascular and Renal Protective Effects of Vitamin D and Coenzyme Q10 in l-NAME-Induced Hypertensive Rats.

BACKGROUND: Hypertension is one of the primary modifiable risk factors for cardiovascular disease. Adequate vitamin D (vit D) levels have been shown to reduce vascular smooth muscle contraction and to increase arterial compliance, which may be beneficial in hypertension. Further, coenzyme Q10 (COQ10) through its action to lower oxidative stress has been reported to have beneficial effects on hypertension and heart failure. This study examined the possible cardiac and renal protective effects of vit D and COQ10 both separately and in combination with an angiotensin II receptor blocker, valsartan (vals) in l-NAME hypertensive rats. MATERIALS AND METHODS: Hypertension was induced in rats by l-NAME administration. Following induction of hypertension, the rats were assigned into the following 6 subgroups: an l-NAME alone group and treated groups receiving the following drugs intraperitoneally for 6 weeks; vals, vit D, COQ10 and combination of vals with either vit D or COQ10. A group of normotensive rats were used as negative controls. At the end of the treatment period, blood pressure, serum creatinine, blood urea nitrogen, lipids and serum, cardiac and renal parameters of oxidative stress were measured. RESULTS: Compared to the l-NAME only group, all treatments lowered systolic, diastolic, mean arterial pressure, total cholesterol, low-density lipoprotein cholesterol, and creatinine levels as well as TNF-α and malondialdehyde. Further, the agents increased serum, cardiac and renal total antioxidant capacity. Interestingly, the combination of agents had further effects on all the parameters compared to treatment with each single agent. CONCLUSIONS: The study suggests that the additive protective effects of vit D and COQ10 when used alone or concurrent with vals treatment in hypertensive rats may be due to their effects as antioxidants, anticytokines and blood pressure conservers.

Effect of variable antidiabetic treatments strategy on oxidative stress markers in obese patients with T2DM.

AIM: To evaluate the effect of different anti-diabetic treatment strategy on oxidative stress markers in patients with type 2 diabetes mellitus (T2DM). SUBJECT AND METHODS: A total of 93 patients with T2DM treated with metformin (G1 = 25), OHA (G2 = 22), OA and insulin (G3 = 26) and insulin alone (G4 = 20). In all patients, lipid profile and glycemic indices were assessed using routine laboratory tests. MDA and Oxidized LDL were assessed using commercially available ELISA kits. Laboratory tests were performed at baseline and at a control visit after 24 weeks of treatment. RESULTS: A significant decrease in the levels of MDA with improvement of glycemic control was observed in the group receiving OHA in combination with insulin therapy. A similar decrease of oxLDL was observed in all diabetic subgroups with borderline significance in those receiving metformin alone. The remaining clinical and biochemical parameters were not changed during follow-up in any of the involved groups. CONCLUSION: A combination therapy with insulin was more effective in glycemic control and MDA reduction in T2DM. Whereas, a significant oxLDLc reduction was observed in T2DM irrespective of categories of antidiabetic treatment or glycemic control.

Trace Element Alterations in the Hair of Diabetic and Obese Women.

Alterations in the trace element content can induce metabolic disorders as these elements are involved in the regulation of metabolism. Obesity increases the likelihood of various diseases, particularly cardiovascular disease and type 2 diabetes, and is more prevalent in Saudi Arabia, especially in women. This study explored the potential of alterations in hair trace elements as long-term markers in diabetic and/or obese Saudi females. In total, 65 diabetic obese women, 47 non-diabetic obese women, and 70 normal-weight women were recruited. Clinical and familial history and anthropometric variables were recorded. Hair Se, Zn, Cu, Mn, and Fe levels were analyzed. Fasting blood sugar (FBS), glycated hemoglobin (HbA1c), and lipid profile were analyzed. Our findings revealed a marked decrease of hair Zn, Mn, and Fe and elevated Se and Cu levels in obese women. In addition, Zn and Fe levels were decreased in diabetic women. Thus, the metabolic distress occurring in obesity and hyperglycemia may affect trace element status by increasing the excretion and decreasing the bioavailability of trace elements or redistributing them among various pools. Hair trace elements can serve as important long-term markers for metabolic disorders; however, larger prospective studies are warranted to validate their diagnostic and follow-up utilities.

Lipid peroxidation is associated with poor control of type-2 diabetes mellitus.

BACKGROUND: Hyperglycemia increases oxidative stress through the overproduction of reactive oxygen species, which results in an imbalance between free radicals and the antioxidant defense system of the cells. A positive correlation was reported between lipid peroxide levels and diabetic complication. OBJECTIVES: The aim of the present study was to investigate the state of oxidative stress in controlled and uncontrolled diabetic patients. METHODS: One hundred thirty nine participants were included in this study, grouped as: Group-I: Healthy Control group of non-diabetic normal subjects, Group-II: Controlled type-2 DM group of subjects with type-2 DM and HbA1c≤8% and Group-III: Uncontrolled type-2 DM group of subjects with type-2 DM and HbA1c>8%. Fasting blood glucose, 2h postprandial glucose, MDA and HbA1c were quantified. The association between diabetic control and lipid peroxidation (malondialdehyde) was evaluated. RESULTS: The mean HbA1c increased significantly in uncontrolled type-2 DM subjects compared to controlled type-2 DM group. Lipid peroxidation as expressed in MDA was significantly increased in uncontrolled type-2 DM group compared to controlled type-2 DM, both groups show significant elevation in this parameter compared to healthy subjects. There is a significant positive correlation between MDA and HbA1c in the studied subjects. CONCLUSION: The core problem during diabetes is poor glycemic control, which leads to protein glycation, lipid peroxidation, oxidative stress and finally varieties of complications. Periodic evaluation of lipid peroxidation products in diabetes mellitus is recommended as it could contribute to the early identification and management of oxidative stress.

Biomarkers of oxidative stress in acute and chronic bronchial asthma.

OBJECTIVE: Oxidative stress plays an important role in inflammatory diseases of the airways, such as bronchial asthma. This study highlights the effects of the imbalance of oxidant/antioxidant parameters and their roles in the severity of asthma, in order to target the deficiency of antioxidants when treating asthmatic patients. METHODS: The study included 45 male and 45 female subjects, aged 18-48 years, with and without asthma. They were classified into 3 groups: G1 was healthy volunteers (CT, n = 15), G2 included patients with stable (chronic) conditions of asthma from the outpatients department (OP, n = 15), and G3 included patients admitted emergency room (ER, n = 15) with acute asthma attacks. For all subjects, the levels of total antioxidant capacity (TAC), reduced glutathione (GSH), malondialdehyde (MDA), and uric acid were colorimetrically estimated. The correlations between the studied parameters were statistically analyzed. RESULTS: The levels of TAC and GSH in asthmatic patients, either male or female, were significantly decreased in the ER more than in the OP group as compared to the control (p < 0.001). MDA increased significantly in the ER group and over the OP group when compared with healthy subjects. Significant positive correlations (p < 0.001) were observed between MDA and other studied parameters TAC (r = -0.74), GSH (r = -0.69), and uric acid (r = -0.35). CONCLUSIONS: The levels of total antioxidants were inversely related to the severity of asthma as observed in asthmatic patients visiting outpatient clinics and patients with acute asthmatic attacks admitted to emergency rooms. Meanwhile, those patients with acute attacks showed increased oxidative stress as reflected in the raised MDA levels.

Influence of combinations of digitonin with selected phenolics, terpenoids, and alkaloids on the expression and activity of P-glycoprotein in leukaemia and colon cancer cells.

P-glycoprotein (P-gp or MDR1) is an ATP-binding cassette (ABC) transporter. It is involved in the efflux of several anticancer drugs, which leads to chemotherapy failure and multidrug resistance (MDR) in cancer cells. Representative secondary metabolites (SM) including phenolics (EGCG and thymol), terpenoids (menthol, aromadendrene, ß-sitosterol-O-glucoside, and ß-carotene), and alkaloids (glaucine, harmine, and sanguinarine) were evaluated as potential P-gp inhibitors (transporter activity and expression level) in P-gp expressing Caco-2 and CEM/ADR5000 cancer cell lines. Selected SM increased the accumulation of the rhodamine 123 (Rho123) and calcein-AM (CAM) in a dose dependent manner in Caco-2 cells, indicating that they act as competitive inhibitors of P-gp. Non-toxic concentrations of ß-carotene (40µM) and sanguinarine (1µM) significantly inhibited Rho123 and CAM efflux in CEM/ADR5000 cells by 222.42% and 259.25% and by 244.02% and 290.16%, respectively relative to verapamil (100%). Combination of the saponin digitonin (5µM), which also inhibits P-gp, with SM significantly enhanced the inhibition of P-gp activity. The results were correlated with the data obtained from a quantitative analysis of MDR1 expression. Both compounds significantly decreased mRNA levels of the MDR1 gene to 48% (p<0.01) and 46% (p<0.01) in Caco-2, and to 61% (p<0.05) and 1% (p<0.001) in CEM/ADR5000 cells, respectively as compared to the untreated control (100%). Combinations of digitonin with SM resulted in a significant down-regulation of MDR1. Our findings provide evidence that the selected SM interfere directly and/or indirectly with P-gp function. Combinations of different P-gp substrates, such as digitonin alone and together with the set of SM, can mediate MDR reversal in cancer cells.

Effects of diet-induced obesity on protein expression in insulin signaling pathways of skeletal muscle in male Wistar rats.

BACKGROUND: The prevalence of diet-induced obesity is increasing globally, and posing significant health problems for millions of people worldwide. Diet-induced obesity is a major contributor to the global pandemic of type 2 diabetes mellitus. The reduced ability of muscle tissue to regulate glucose homeostasis plays a major role in the development and prognosis of type 2 diabetes. In this study, an animal model of diet-induced obesity was used to elucidate changes in skeletal muscle insulin signaling in obesity-induced diabetes. METHODS: Adult male Wistar rats were randomized and assigned to either a control group or to a test group. Controls were fed a standard laboratory pellet diet (chow-fed), while the test group had free access to a highly palatable diet (diet-fed). After 8 weeks, the diet-fed animals were subdivided into three subgroups and their diets were altered as follows: diet-to-chow, diet-fed with addition of fenofibrate given by oral gavage for a further 7 weeks, or diet-fed with vehicle given by oral gavage for a further 7 weeks, respectively. RESULTS: Untreated diet-fed animals had a significantly higher body weight and metabolic profile than the control chow-fed animals. Intramuscular triacylglyceride levels in the untreated obese animals were significantly higher than those in the control chow-fed group. Expression of protein kinase C beta, phosphatidylinositol 3, Shc, insulin receptor substrate 1, ERK1/2, and endothelial nitric oxide synthase was significantly increased by dietary obesity, while that of insulin receptor beta, insulin receptor substrate 1, and protein kinase B (Akt) were not affected by obesity. CONCLUSION: These data suggest that diet-induced obesity affects insulin signaling mechanisms, leading to insulin resistance in muscle.

The effects of diet-induced obesity on hepatocyte insulin signaling pathways and induction of non-alcoholic liver damage.

The prevalence of diet-induced obesity is increasing amongst adults and children worldwide, predisposing millions of people to an array of health problems that include metabolic syndrome, non-alcoholic fatty liver disease and non-alcoholic steatohepatitis. In this study we used experimental animals to investigate the effects of dietary obesity on markers of hepatic insulin signaling as well as structural changes in hepatocytes. Adult male Wistar rats were randomized and assigned to either a control group or a test group. Controls were fed standard laboratory pelleted diet (chow-fed), while the test group had free access to a highly-palatable diet (HPD). After eight weeks, the HPD-fed animals were subdivided into three subgroups and their diets altered as follows: HPD-to-chow, HPD with the addition of fenofibrate given by oral gavage for a further seven weeks, or HPD with vehicle (1% carboxymethylcellulose at 1 mL/kg body weight) given by oral gavage for a further seven weeks, respectively. Untreated diet-fed animals had significantly higher body weight, liver weight, and all measured metabolic profiles compared with chow-fed and treated diet-fed groups. Expression of kinases IRß, IRS-1, AKt, eNOS, Shc and ERK1/2 were unaffected by obesity, while IRS-2 and P I3 kinase levels were significantly reduced in untreated HPD animals. Compared with chow-fed animals, steatosis and steatohepatitis were almost doubled in animals from untreated HPD, while removal of HPD and fenofibrate-treatment reduced steatosis by 40% and 80% respectively. These data suggest that diet-induced obesity affects intracellular insulin signaling mechanisms, namely IRS-2 and PI 3-kinase, leading to hepatic insulin resistance. Moreover, diet-induced obesity induces fatty liver, an effect which can be reversed by either removal of the source of obesity or treatment with fenofibrate, a peroxisome proliferator-activated receptor alpha agonist.

The effects of physiological and pharmacological weight loss on adiponectin and leptin mRNA levels in the rat epididymal adipose tissue.

In subjects with obesity, diabetes and coronary artery disease, circulating levels of leptin increased while that of adiponectin is decreased. In this study we have investigated effects of physiological and pharmacological weight reduction on leptin and adiponectin mRNA expression. Wistar rats were fed either standard laboratory chow for 16 weeks (chow-fed) or given a fat-enriched, glucose-enriched diet (diet-fed) for 8 weeks. After 8 weeks, diet-fed group was subdivided into three subgroups, namely, an untreated obese, or were returned to chow diet, or treated with fenofibrate for further 8 week. After 16 weeks, compared with chow-fed group, diet-fed rats had significantly higher body weight, epididymal fat pad mass, and plasma levels of insulin, leptin, adiponectin, non-esterified fatty acids and triglycerides (P<0.001, for all). Moreover, untreated obese rats had significantly (P<0.01, for both) raised levels of Ob mRNA but reduced adiponectin mRNA levels in epididymal fat pads compared with chow-fed group. These changes were corrected by chronic removal of the high-energy diet and fenofibrate treatment. These findings indicate that physiological or pharmacological lowering of body weight together with circulating plasma lipids play a significant role in leptin and adiponectin synthesis and metabolism.

Differential vascular dysfunction in response to diets of differing macronutrient composition: a phenomenonological study.

BACKGROUND: Vascular dysfunction can develop from consumption of an energy-rich diet, even prior to the onset of obesity. However, the roles played by different dietary components remain uncertain. While attempting to develop models of obesity in a separate study, we observed that two high-energy diets of differing macronutrient compositions affected vascular function differently in overweight rats. METHODS: Male Wistar rats (n = 6/group) were fed diets providing varying percentages of energy from fat and carbohydrate (CHO). For 10 weeks, they were fed either chow, as control diet (10% of energy from fat; 63% from CHO), chow supplemented with chocolate biscuit (30% fat; 56% CHO) or a high-fat diet (45% fat; 35% CHO). Blood concentrations of biochemical markers of obesity were measured, and epididymal fat pads weighed as a measure of adiposity. Mesenteric arteries were dissected and their contractile and relaxant properties analysed myographically. Data were tested by analysis of variance (ANOVA). RESULTS: Weight gain and plasma concentrations of glucose, insulin and leptin were similar in all groups. However, biscuit-fed animals showed increased food intake (+27%; p < 0.01) and elevated concentrations of TGs and NEFAs (+41% and +17%; both p < 0.05). High-fat-fed animals showed an increase only in NEFAs (+38%; p < 0.01). Arterial vasoconstriction in response to NA and KCl increased only in biscuit-fed rats (both p < 0.01), while vasorelaxation in response to CCh and SNP, but not histamine, was attenuated in both groups (both p < 0.01). Furthermore, whereas the effect of the high-fat diet was most pronounced in endothelium-dependent vasorelaxation, the biscuit diet had the greater effect on endothelium-independent vasorelaxation. CONCLUSION: Vascular dysfunction resulting from consumption of a high-fat or combined relatively high-fat/high-CHO diet occurs through different physiological processes, which may be attributable to their differing macronutrient compositions. Combining potentially atherogenic macronutrients induces more extensive vascular impairment than that of high-fat alone, and may be attributable to the more marked dyslipidaemia observed with such a diet. Thus, these findings help clarify the role of dietary components in vascular impairment, which has implications for clinical approaches to preventing cardiovascular disease.

The effects of fenofibrate on metabolic and vascular changes induced by chocolate-supplemented diet in the rat.

Current evidences suggest that diet per se plays an important role in genesis of metabolic and vascular function abnormalities. We have investigated the effects of addition of a high-fat diet (chocolate) in the presence or absence of short-term (7 days) administration of fenofibrate on metabolic and vascular changes in adult male Wistar rats. Despite similarities in total body weight in all groups, compared with control fed groups, chocolate-supplemented animals had significantly higher plasma triacylglyceride and non-esterified fatty acids and leptin (for all, P<0.01), but not glucose or insulin levels. Fenofibrate treatment corrected metabolic changes. In the mesenteric arteries, responses to KCl and noradrenaline were significantly (for both, P<0.01) higher in chocolate-supplemented group. Furthermore, vasorelaxant responses to carbamylcholine, but not to sodium nitroprusside, were significantly (P<0.01) reduced in the chocolate-supplemented group. Although fenofibrate failed to improve noradrenaline and KCl responses, it was effective in improving carbamylcholine-induced vasorelaxation. These data suggest that high-fat diet has a profound effect on plasma lipid profile and vascular function. Furthermore, fenofibrate treatment may ameliorate high-fat diet effects on vascular function and metabolic changes.

Fenofibrate lowers adiposity and corrects metabolic abnormalities, but only partially restores endothelial function in dietary obese rats.

In humans, dietary-induced obesity markedly increases plasma lipid profile and impairs vascular function leading to increased incidence of cardiovascular events. We have recently reported that chronic withdrawal of obesity-inducing diet attenuates obesity and completely corrects endothelial function. The aim of this study was to investigate whether fenofibrate-induced decrease in adiposity would also correct vascular function in the presence of obesity-inducing diet. Wistar rats were fed with either standard laboratory chow (lean, n = 9) or given a highly palatable diet (diet-fed, n = 18) for 15 weeks. After 7 weeks, half of the diet-fed group was treated with fenofibrate (fenofibrate-treated, n = 9) for 8 weeks before being sacrificed. Untreated diet-fed (n = 9) rats had significantly higher body weight, total fat mass (by up to two-fold, p < 0.001 for both), and raised fasting plasma levels of insulin, leptin and triglycerides (up to 110%; p < 0.001), but not glucose or nonesterified fatty acids (NEFA) than both lean control and fenofibrate-treated groups. Resistance mesenteric arteries responses to KCl- and noradrenaline-induced vasoconstriction were similar in all three groups. However, compared with lean controls, endothelium-dependent vasorelaxation responses were shifted to the right in both untreated and fenofibrate-treated diet-fed groups. Fenofibrate treatment improved endothelium-dependent vasorelaxation at only high carbamycholine concentrations (10 microM). There were no differences in endothelium-independent vasorelaxation between the three groups. These results indicate that, in the presence of obesity-inducing diet, fenofibrate markedly reverses obesity and corrects insulin resistance and lipid profile, but it only has a limited beneficial effect on vascular function. Therefore, it seems that diet component rather than obesity per se plays a key role in the genesis of vascular abnormalities.