Oladipo Ademuyiwa

Plasma lipid profiles and risk of cardiovascular disease in occupational lead exposure in Abeokuta, Nigeria

In order to investigate the effects of lead exposure on risk of cardiovascular disease during occupational exposure to this metal, plasma cholesterol and its fractions as high-density liporotein (HDL), low-density liporotein (LDL) and triglyceride were determined in various artisans in Abeokuta, Nigeria who have been shown to be occupationally exposed to lead and these were related to blood lead levels. Increased risk of cardiovascular disease was observed in the artisans. Total cholesterol in the artisans was between 1.5 and 2.0 times higher in the artisans than that present in controls while LDL cholesterol was between 1.6 and 2.4 times higher in the artisans when compared with control subjects [p < 0.001]. HDL cholesterol and triglyceride levels were not affected [p > 0.05]. A significant positive correlation was observed between blood lead and total cholesterol on one hand [r = 0.372; p = 3.0 × 10-5] and blood lead and LDL cholesterol on the other hand [r = 0.283; p = 0.001]. LDL/HDL cholesterol ratio was also higher in the artisans when compared with control. Blood pressure (systolic and diastolic) and other anthropometric parameters were not significantly different between the artisans and the control subjects [p > 0.05]. Results suggest that lead exposure increases cholesterol synthesis and transport to peripheral tissues whereas reverse cholesterol transport to the liver is not affected.

Erythrocyte acetylcholinesterase activity as a surrogate indicator of lead-induced neurotoxicity in occupational lead exposure in Abeokuta, Nigeria

Dose-effect and dose-response relationships in occupational neurotoxicology are rarely studied by means of biochemical methods. In order to investigate the potential neurotoxic effects of lead during occupational exposure to this metal, the activity of erythrocyte acetylcholinesterase (AcChE), as well as blood pressure and pulse, were determined in various artisans in Abeokuta, Nigeria, who have been shown to be occupationally exposed to lead, and these were related to blood lead levels. AcChE activity in the artisans was inhibited to varying extents. While AcChE activity was inhibited to the tune of 39% in the male petrol station attendants, the inhibition amounted to 32% in female petrol station attendants. In other artisans, AcChE inhibition ranged from 31% in the welders to 38% in painters. The lowest inhibition of 15% was obtained in the panel beaters. Correlations, as calculated by Pearsons method, revealed a significant (p<0.001) inverse linear relationship between AcChE activity and blood lead levels (r=-0.40; y=-120.38x+13935.59; p<0.001). Blood pressure and pulse were not significantly different between control and lead-exposed subjects. Our findings suggest that erythrocyte AcChE activity could be used as a biomarker of lead-induced neurotoxicity in occupationally exposed subjects.

Endogenous antioxidant defences in plasma and erythrocytes of pregnant women during different trimesters of pregnancy

Background. To assess the antioxidant capacity of pregnant women in Ogun State, Nigeria. Methods. The activities of total superoxide dismutase (total SOD), manganese superoxide dismutase (Mn‐SOD), catalase (CAT), glutathione transferase (GST), aminolevulinic acid dehydratase (ALAD), and the concentrations of glutathione (GSH), were determined in the plasma and red blood cells of non‐pregnant (n = 20), normal healthy pregnant women during different trimesters of pregnancy (n = 90), and pregnant women with pre‐eclampsia (n = 7). Results. A 2‐fold increase in erythrocyte CAT activity was observed in the pregnant women (p<0.05), while CAT activity in the pre‐eclamptic women was not significantly different from control (p>0.05). A 3‐fold increase in plasma Mn‐SOD was observed in the pregnant women including those with pre‐eclampsia (p<0.05). ALAD activities in the first, second and third trimesters of pregnancy were 35, 51 and 55% of control, respectively (p<0.05), while in the women with pre‐eclampsia it was 31% of control (p<0.05). Total SOD also decreased significantly in the erythrocytes of the pre‐eclamptic women (p<0.05). Other antioxidants (GST and GSH) were not affected. Conclusions. Results suggest that oxidative stress is higher in pregnancy than in non‐pregnant state. Our findings also suggest that while plasma Mn‐SOD might play a significant role in detoxifying the superoxide anions produced in the placenta, the decomposition of hydrogen peroxide in erythrocytes is mainly due to CAT activity. Whether inhibition of ALAD contributes to the etiology of pre‐eclampsia remains to be elucidated.

Biomarkers of lead exposure in petrol station attendants and auto-mechanics in Abeokuta, Nigeria: effect of 2-week ascorbic acid supplementation

In order to study the ameliorative effects of ascorbic acid in chronic lead poisoning, petrol station attendants and auto-mechanics in Abeokuta, Nigeria, who have been shown to be occupationally exposed to lead and university students (serving as control), were supplemented daily with 500mg ascorbic acid for 2 weeks. Blood and urine samples were collected from the subjects before and after ascorbic acid regimen and analysed for lead and biochemical effects associated with lead toxicity. The 2-week ascorbic acid supplementation resulted in a significant (P < 0.05) reduction in blood lead in the occupationally exposed subjects. The reduction in blood lead amounted to 57% in male petrol station attendants, 50% in female petrol station attendants and 44% in the auto-mechanics. Urinary excretion of lead increased remarkably in the occupationally exposed subjects (P < 0.05). The biochemical effects associated with the toxic effects of lead also responded positively to the ascorbic acid regimen. Plasma and urine aminolevulinic acid (ALA) were reduced significantly (P < 0.05) by as much as 55% and 57% respectively. Plasma calcium also increased significantly (P < 0.05) in the subjects. Decreased levels of reduced glutathione (GSH) and hemoglobin observed in the occupationally exposed subjects were reversed by ascorbic acid. Glutathione-S-transferase (GST) and catalase (CAT) activities were not affected. Our findings indicate that ascorbic acid may be useful as an economical and convenient prophylactic agent for lead poisoning.

Reversal of aminolevulinic acid dehydratase (ALAD) inhibition and reduction of erythrocyte protoporphyrin levels by Vitamin C in occupational lead exposure in Abeokuta, Nigeria.

In order to investigate the toxic effects of lead during occupational exposure to this metal, the activity of aminolevulinic acid dehydratase (ALAD) and the concentrations of erythrocyte protoporphyrin (EPP) were determined in blood of various artisans in Abeokuta, Nigeria and these were related to blood lead levels. ALAD activity in the artisans was inhibited to varying extents. ALAD activity was inhibited to the tune of 77% in petrol station attendants while the lowest inhibition of 36% was obtained in the welders. EPP was also significantly increased in the artisans (p<0.001). The highest EPP level of 241.57±89.27μg/100ml of red blood cell was observed in upholsterers. A significant (p<0.001) negative correlation was observed between ALAD activity and blood lead levels on one hand (r=-0.631) and between ALAD activity and EPP on the other hand (r=-0.461). Administration of a daily dose of 500mg ascorbic acid for 2 weeks reversed the lead-induced inhibition of ALAD. Increased EPP levels observed in the artisans also responded positively to the ascorbic acid supplementation. A significant reduction (p<0.001) in blood lead was also observed in the artisans at the end of the 2-week ascorbic acid therapy. Our findings indicate that ascorbic acid may offer more advantages over the conventional agents for the treatment of lead poisoning, especially in cases where the subjects cannot be removed from the source of lead exposure.

Effects of Fibre-Enriched Diets on Tissue Lipid Profiles of MSG Obese Rats

In order to investigate the influence of some fibre-enriched diets on tissue lipids in an animal model of obesity induced by the administration of monosodium glutamate (MSG), obese rats were fed diets containing 30% of Acha, Cassava, Maize and Plantain for five weeks and weight gain, feed intake and lee index were recorded. The lipid profiles of plasma, erythrocytes, kidney, heart and liver as well as hepatic 3-hydroxyl-3-methylglutaryl-CoA (HMG-CoA) reductase activity were measured. The diets significantly (p<0.05) reduced weight gain and lee index in the obese rats. Obesity-induced increase in plasma and erythrocytes lipid levels was significantly (p<0.05) reduced by these diets. MSG-induced obesity also resulted in a significant increase (p<0.05) in hepatic cholesterol level which was reduced by the diets. MSG-obesity was characterised by a significant (p<0.05) increase in cholesterol, triacylglycerol and phospholipids in kidney and this was reversed by the diets except Maize which did not reverse the increased cholesterol level. Only Acha reversed the obesity-induced increase in heart cholesterol and phospholipids. The increased activity of hepatic HMG-CoA reductase associated with obesity was also significantly (p<0.05) reduced by the diets. In conclusion, dyslipidemia associated with MSG-induced obesity could be attenuated by consumption of fibre-enriched diets.

Effects of sub-chronic low-level lead exposure on the homeostasis of copper and zinc in rat tissues.

Information about the health risks or the subtle adverse health effects that might be associated with low-level lead exposure on micronutrient metabolism are scarce in the literature. The present work investigated the subtle adverse health effects of exposure to progressively low levels of lead on the metabolism of two micronutrients, copper and zinc in different tissues of the rat. Rats were exposed to 200, 300 and 400 ppm lead in their drinking water for 12 weeks. Lead, copper and zinc concentrations were determined in blood, liver, kidney, heart, spleen and brain of the animals. While the imbalance in zinc metabolism was characterized by a deposition of zinc in the kidney and to a lesser extent in the heart of the animals, imbalance in copper metabolism was characterized by a depletion of blood and splenic copper concentrations as well as renal and cardiac accumulation of copper. Hepatic and brain copper and zinc contents, together with blood zinc were not affected by the 12-week lead exposure. A linear relationship was observed between lead dose and lead accumulation in the spleen, whereas a non-linear relationship was observed between lead dose and lead accumulation in blood, liver, kidney and heart. Our findings indicate that exposure to progressively low-level lead concentrations results in imbalance in copper and zinc in the organism and this might be a factor in propensity toward behavioral disorders observed in lead exposure.

Hypolipidemic effects of lactic acid bacteria fermented cereal in rats

BackgroundThe objectives of the present study were to investigate the efficacy of the mixed culture of Lactobacillus acidophilus (DSM 20242), Bifidobacterium bifidum (DSM 20082) and Lactobacillus helveticus (CK60) in the fermentation of maize and the evaluation of the effect of the fermented meal on the lipid profile of rats.MethodsRats were randomly assigned to 3 groups and each group placed on a Diet A (high fat diet into which a maize meal fermented with a mixed culture of Lb acidophilus (DSM 20242), B bifidum (DSM 20082) and Lb helveticus (CK 60) was incorporated), B (unfermented high fat diet) or C (commercial rat chow) respectively after the first group of 7 rats randomly selected were sacrificed to obtain the baseline data. Thereafter 7 rats each from the experimental and control groups were sacrificed weekly for 4 weeks and the plasma, erythrocytes, lipoproteins and organs of the rats were assessed for cholesterol, triglyceride and phospholipids.ResultsOur results revealed that the mixed culture of Lb acidophilus (DSM 20242), B bifidum (DSM 20082) and Lb helveticus (CK 60) were able to grow and ferment maize meal into ‘ogi’ of acceptable flavour. In addition to plasma and hepatic hypercholesterolemia and hypertriglyceridemia, phospholipidosis in plasma, as well as cholesterogenesis, triglyceride constipation and phospholipidosis in extra-hepatic tissues characterized the consumption of unfermented hyperlipidemic diets. However, feeding the animals with the fermented maize diet reversed the dyslipidemia.ConclusionThe findings of this study indicate that consumption of mixed culture lactic acid bacteria (Lb acidophilus (DSM 20242), Bifidobacterium bifidum (DSM 20082) and Lb helveticus (CK 60) fermented food results in the inhibition of fat absorption. It also inhibits the activity of HMG CoA reductase. This inhibition may be by feedback inhibition or repression of the transcription of the gene encoding the enzyme via activation of the sterol regulatory element binding protein (SREBP) transcription factor. It is also possible that consumption of fermented food enhances conversion of cholesterol to bile acids by activating cholesterol-7α-hydroxylase.

Inability of Legumes to Reverse Diabetic-Induced Nephropathy in Rats Despite Improvement in Blood Glucose and Antioxidant Status

Diabetes mellitus has assumed epidemic proportions in most parts of the world, including developing countries, with vascular and renal complications being the major causes of death. Evidence is emerging that legumes play a beneficial role in diabetes and its associated complications. In connection with the above, four groups of alloxan-induced diabetic rats were fed on four different legume-based (Vigna unguiculata ssp. dekindtiana var. dekindtiana, V. unguiculata ssp. unguiculata, Sphenostylis stenocarpa, and Vigna subterranean) diets. Feeding rats with these diets for 5 weeks resulted in reduction of plasma glucose and changes in biomarkers of oxidative stress-namely, superoxide dismutase (SOD), peroxidase (PER), and thiobarbituric acid-reactive substances (TBARS). None of the legumes reversed the increase in plasma total protein associated with diabetes. The legumes increased PER activity and decreased the level of TBARS in the erythrocytes. A decrease in the activities of PER and SOD was observed in the kidneys of the diabetic rats. Nitric oxide (NO) production in the erythrocytes of the diabetic rats (as an index of diabetic endothelial dysfunction) increased for all the legumes in the following order: V. unguiculata ssp. unguiculata, V. unguiculata ssp. dekindtiana var. dekindtiana, V. subterranean, and S. stenocarpa. There was a significant increase (P < .05) in the uric acid concentration in the kidneys of treated rats. It is concluded that while the legumes have beneficial effects on reduction of hyperglycemia and strengthening the antioxidant status of the diabetic animals, the increased kidney uric acid concentration should be of concern.

Coexistence of Aflatoxicosis with Protein Malnutrition Worsens Hepatic Oxidative Damage in Rats

To investigate the effects of the coexistence of aflatoxin B1 (AFB1) and protein malnutrition in rat liver, weanling rats were fed either normal protein diet (20% protein), low‐protein (PEM) diet (5%), normal protein diet + 40 ppb AFB1, or low‐protein diet + 40 ppb AFB1. After 8 weeks, biomarkers of hepatic functions and oxidative stress, caspase‐3 activity, and tumor suppressor protein 53 (p53) were determined spectrophotometrically. Randomly amplified polymorphic DNA polymerase chain reaction (RAPD‐PCR) was employed to determine genomic alterations among the groups. Coexistence of aflatoxicosis and PEM significantly decreased glutathione, glutathione‐S‐transferase, glutathione peroxidase, and superoxide dismutase, while it increased peroxidase and catalase. RAPD‐PCR showed genomic alterations that were associated with significant increases in p53 level and caspase‐3 activity in rats fed PEM diet + AFB1. In conclusion, the coexistence of aflatoxicosis and protein malnutrition induced oxidative stress with concomitant genomic alterations in the liver of weanling rats.