Inocent Gouado

Elevated Cell-Specific Microparticles Are a Biological Marker for Cerebral Dysfunctions in Human Severe Malaria

Cerebral malaria (CM) and severe anemia (SA) are the most severe complications of Plasmodium falciparum infections. Although increased release of endothelial microparticles (MP) correlates with malaria severity, the full extent of vascular cell vesiculation remains unknown. Here, we characterize the pattern of cell-specific MP in patients with severe malaria. We tested the hypothesis that systemic vascular activation contributes to CM by examining origins and levels of plasma MP in relation to clinical syndromes, disease severity and outcome. Patients recruited in Douala, Cameroon, were assigned to clinical groups following WHO criteria. MP quantitation and phenotyping were carried out using cell-specific markers by flow cytometry using antibodies recognizing cell-specific surface markers. Platelet, erythrocytic, endothelial and leukocytic MP levels were elevated in patients with cerebral dysfunctions and returned to normal by discharge. In CM patients, platelet MP were the most abundant and their levels significantly correlated with coma depth and thrombocytopenia. This study shows for the first time a widespread enhancement of vesiculation in the vascular compartment appears to be a feature of CM but not of SA. Our data underpin the role of MP as a biomarker of neurological involvement in severe malaria. Therefore, intervention to block MP production in severe malaria may provide a new therapeutic pathway.

Systemic levels of carotenoids from mangoes and papaya consumed in three forms (juice, fresh and dry slice)

Background:Vitamin A deficiency is a public health problem in Cameroon. Data on the bioavailability of carotenoid in fruits currently consumed in Cameroon are scarce.Objective:To assess the systemic levels of carotenoids from mangoes and papaya consumed as juice, fresh or dried slices.Methods:Two groups of seven healthy volunteers (24 and 25 years of age; body mass index: 21 and 22 kg/m2 respectively for subjects fed mango and papaya), were submitted to three types of meal treatments (juice, fresh and dried fruit). On the experiment day, meals served to fasting subjects during breakfast, included bread, yogurt and one of the three forms of fruit. All the treatments lasted only one day during which blood samples were collected three times; during fasting (T 0), 4 h (T 4) and 8 h (T 8) after the test meal. The carotenoids and retinol contents were analysed by high-performance liquid chromatography method.Results:From the major carotenoids present in papaya and mangoes, lutein, α-carotene and β-carotene were found in considerable amounts. Lycopene and cryptoxanthin that were the major carotenoids in papaya samples appeared in low amounts in the chylomicrons. Significant correlations were observed between these carotenoids (at T 0, T 4 and T 8). The three forms of consumption contributed to the rise of serum retinol levels. A comparison between the three forms revealed that papaya and mangoes consumed in form of juice or fresh fruit are the best forms because they had higher bioavailability values.Conclusion:Association of these different forms of consumptions could lead to a better availability of these fruits throughout the year and therefore efficiently contribute to improve vitamin A status of the population.

Biochemical markers of nutritional status and childhood malaria severity in Cameroon.

To investigate the part played by undernutrition in malaria severity, some biomarkers of nutritional status were assessed in children with severe malarial anaemia (MA) and cerebral malaria (CM) in comparison with healthy children or those with uncomplicated malaria. Undernutrition was assessed using the weight-for-age Z score (WAZ). Retinol was determined by HPLC; lipid profile, Ca, Mg and albumin were determined by spectrophotometry. Severe and moderate undernutritions were more prevalent in children with MA and those with the combined symptoms of CM and MA, but not in those with CM alone. Some perturbations were noticed in the lipid profile, but most of the values remained within the normal ranges. The risk of vitamin A deficiency, as assessed by plasma retinol concentration, was noteworthy in children with severe malaria: 0.48 × 10(-6) and 0.50 × 10(-6) mol/l, respectively, in children with MA and CM (reference value: >0.7 × 10(-6) mol/l). A significant difference was obtained for retinol values after an ANOVA of all the groups (P = 0.0029), with the value in the MA group being significantly low than that in the control group (P < 0.05); likewise, a significant difference was obtained after comparison of all the groups for Mg and albumin (P = 0.0064 and 0.0082, respectively). Despite their low number (n 6), fatal cases of CM had a normal mean WAZ on admission, but low values of retinol, albumin and HDL:LDL ratio. Despite these associations, undernutrition itself did not appear to be a primary factor associated with fatal outcome.

Does malaria epidemiology project Cameroon as ‘Africa in miniature’?

Cameroon, a west-central African country with a ~20 million population, is commonly regarded as ‘Africa in miniature’ due to the extensive biological and cultural diversities of whole Africa being present in a single-country setting. This country is inhabited by ancestral human lineages in unique eco-climatic conditions and diverse topography. Over 90% Cameroonians are at risk of malaria infection, and ~41% have at least one episode of malaria each year. Historically, the rate of malaria infection in Cameroon has fluctuated over the years; the number of cases was about 2 million in 2010 and 2011. The Cameroonian malaria control programme faces an uphill task due to high prevalence of multidrug-resistant parasites and insecticide-resistant malaria vectors. Above all, continued human migration from the rural to urban areas as well as population exchange with adjoining countries, high rate of ecological instabilities caused by deforestation, poor housing, lack of proper sanitation and drainage system might have resulted in the recent increase in incidences of malaria and other vector-borne diseases in Cameroon. The available data on eco-environmental variability and intricate malaria epidemiology in Cameroon reflect the situation in the whole of Africa, and warrant the need for in-depth study by using modern surveillance tools for meaningful basic understanding of the malaria triangle (host-parasite-vector-environment).

Serum Concentration of Vitamins A and E and Lipid in a Rural Population of North Cameroon

Background: Vitamin A deficiency is still a major health problem mostly affecting people in developing countries. It contributes to increased mortality and morbidity through current infection. In Cameroon, it is a public health problem mostly in the northern part where palm oil, which is a principal source of provitamin A in the south of the country, is not consumed. Aim: We carried out this research to discover the relationship between vitamins (A and E) and blood lipids in a normal rural population living in vitamin A-deficiency area. Design: A cross-sectional study with 81 healthy volunteers (40 men and 41 women) aged 3–61 (mean 18.32 ± 1.63) years and living in two neighboring villages (Doyan and Larao) in the northern part of Cameroon, where previous studies revealed a prevalence of vitamin A deficiency of 33.3%. Methods: Serum concentrations of vitamins A and E were measured by fluorometric methods. Serum cholesterol and lipids were assayed by enzymatic methods. Results: The mean ± standard error for vitamin A and E were 15.09 ± 0.82; 526.99 ± 29.57 µg/100 ml, respectively. The concentrations of the serum parameters analyzed were similar for both sexes, whereas the atherogenic ration of cholesterol (ARC) was significantly (p < 0.036) higher in women. Serum lipids (total lipids, total cholesterol, low-density lipoprotein and phospholipids) correlated with vitamins A and E (p < 0.05). Vitamins A and E were highly correlated with each other (r = 0.42, p < 0.001). Age was positively associated with vitamin A (r = 0.42, p < 0.001) and vitamin E (r = 0.29, p < 0.01). Deficiency of vitamins A and E constitutes a public health problem with more than 56% of the subjects having low levels of these vitamins, while subjects tested had a low risk for cardiovascular diseases. Conclusion: In this population we noticed normal lipid levels and vitamin A deficiency probably resulting from diets poor in provitamin A.

The Influence of Iron and Zinc Supplementation on the Bioavailability of Provitamin A Carotenoids from Papaya Following Consumption of a Vitamin A-Deficient Diet

Iron deficiency anemia, zinc and vitamin A deficiencies are serious public health problems in Cameroon, as in many developing countries. Local vegetables which are sources of provitamin A carotenoids (PACs) can be used to improve vitamin A intakes. However, traditional meals are often unable to cover zinc and iron needs. The aim of this study was to determine the bioavailability of 3 PACs (α-carotene, β-carotene, and β-cryptoxanthin) in young men, who were fed with a vitamin A-free diet and received iron and zinc supplementation. Twelve healthy participants were divided into three groups and were supplemented with elemental iron (20 mg of iron fumarate), 20 mg of zinc sulfate or iron+zinc (20 mg of iron in the morning and 20 mg of zinc in the evening) for 11 d. They were given a vitamin A- and PAC-free diet from the 6th to the 11th day, followed by a test meal containing 0.55 kg of freshly peeled papaya as a source of PACs. Blood samples were collected four times successively on the 11th day (the test meal day), at T0 (just after the test meal), after 2 h (T2), after 4 h (T4) and after 7 h (T7). Ultracentrifugation was used to isolate serum chylomicrons. Retinol appearance and PAC postprandial concentrations were determined. The supplementation with zinc, iron and iron+zinc influenced the chylomicron appearance of retinol and PACs differently as reflected by retention times and maximum absorption peaks. Iron led to highest retinol levels in the chylomicron. Zinc and iron+zinc supplements were best for optimal intact appearance of α-carotene, β-carotene and β-cryptoxanthin respectively. Supplementation with iron led to the greatest bioavailability of PACs from papaya and its conversion to retinol.

Evaluation of oxidative stress and antioxidant status of pregnant women suffering from malaria in Cameroon

Oxidative stress is thought to be involved in the pathophysiology of malaria, especially in pregnancy where natural resistance is markedly reduced. In the present study we investigated oxidative stress in 315 pregnant women out of which 159 had Plasmodium falciparum malaria and 154 controls. We evaluated the level of lipid peroxidation products (MDA level) in the plasma, the activity of erythrocyte antioxidant defense enzymes, superoxide dismutase (SOD, EC: 1.15.1.1) and catalase (Cat, EC: 1.11.1.6) as well as the ability to resist oxidative stress by the FRAP (Ferric Reducing Ability of Plasma) assay. Total erythrocyte protein levels were also examined. For the two groups of patients, several differences between the biochemical parameters tested were found. Median parasitaemia in women with malaria was 25,392 parasites/μl of blood (Range1200–82000), while in controls we had no parasites found in thin and thick smears. Levels of lipid peroxidation products (MDA) were significantly higher in patients with parasitemia than in healthy asymptomatic volunteers (mean: 0.844 ± 0.290 and 0.384 ± 0.129 respectively, p<0.001). This MDA level was higher in primigravidea and also correlates well with parasite density (p<0.001). Catalase activity in erythrocytes of women with malaria did not differ statistically from that of controls. In contrast, SOD activity of patients with malaria was found to be significantly higher than that of controls (mean: 0.7899 ± 0.2777 and 0.4263 ± 0.2629 respectively, p<0.05). FRAP values declined, from parasitemic patients (1.4619 ± 0.6565) compare to controls (2.4396 ± 0.8883, p<0.05), particularly in the first and third trimester of gestation (p<0.05 and p<0.01 respectively). Finally, total erythrocyte protein concentrations of women with malaria did not differ from that of the controls. Our results suggest an imbalance between oxidants and antioxidants in pregnant women suffering from malaria, a situation which could lead to severe damage for either the mother or the fetus. Therefore, further research should be done to assess the potential benefits of antioxidant supplementation for the pregnant women suffering from malaria.

Trace elements in foods of children from Cameroon: A focus on zinc and phytate content

In developing countries, complementary foods are based on local cereal porridges. These foods are poor in trace elements, with a high risk of inducing micronutrient deficiencies-the primary cause of mortality in children under the age of five. Inappropriate feeding of complementary foods is the major factor creating malnutrition and micronutrients deficiencies in Cameroon children, as well as in other developing countries. This study determined the zinc and phytate content of 30 complementary foods that were based on maize or Irish potatoes. The foods were blended or treated by dehusking, fermentation and germination. Zinc was measured by flame atomic absorption spectrophotometry and phytates by high pressure-liquid chromatography; then phytates/zinc molar ratios were calculated. Concentrations (mg/100g dry matter) ranged, respectively, from 0.20 to 2.58 (0.12 ± 0.67) for zinc and from 0.00 to 6.04 (1.87 ± 1.7) for phytates. The phytate/zinc ratio varied from 0.00 to 51.62 (11.12 ± 11.53). It appears that germination and fermentation reduced the level of phytates: however, zinc levels in the samples did not change significantly. The traditional, local complementary foods were not only poor in zinc, but contained very high levels of phytates. These phytates have the potential to considerately reduce the acid extraction of zinc, and could impair its bioavailability.

Evaluation of the international standardized 24-h dietary recall methodology (GloboDiet) for potential application in research and surveillance within African settings

BackgroundCollection of reliable and comparable individual food consumption data is of primary importance to better understand, control and monitor malnutrition and its related comorbidities in low- and middle-income countries (LMICs), including in Africa. The lack of standardised dietary tools and their related research support infrastructure remains a major obstacle to implement concerted and region-specific research and action plans worldwide. Citing the magnitude and importance of this challenge, the International Agency for Research on Cancer (IARC/WHO) launched the “Global Nutrition Surveillance initiative” to pilot test the use of a standardized 24-h dietary recall research tool (GloboDiet), validated in Europe, in other regions. In this regard, the development of the GloboDiet-Africa can be optimised by better understanding of the local specific methodological needs, barriers and opportunities. The study aimed to evaluate the standardized 24-h dietary recall research tool (GloboDiet) as a possible common methodology for research and surveillance across Africa.MethodsA consultative panel of African and international experts in dietary assessment participated in six e-workshop sessions. They completed an in-depth e-questionnaire to evaluate the GloboDiet dietary methodology before and after participating in the e-workshop.ResultsThe 29 experts expressed their satisfaction on the potential of the software to address local specific needs when evaluating the main structure of the software, the stepwise approach for data collection and standardisation concept. Nevertheless, additional information to better describe local foods and recipes, as well as particular culinary patterns (e.g. mortar pounding), were proposed. Furthermore, food quantification in shared-plates and -bowls eating situations and interviewing of populations with low literacy skills, especially in rural settings, were acknowledged as requiring further specific considerations and appropriate solutions.ConclusionsAn overall positive evaluation of the GloboDiet methodology by both African and international experts, supports the flexibility and potential applicability of this tool in diverse African settings and sets a positive platform for improved dietary monitoring and surveillance. Following this evaluation, prerequisite for future implementation and/or adaptation of GloboDiet in Africa, rigorous and robust capacity building as well as knowledge transfer will be required to roadmap a stepwise approach to implement this methodology across pilot African countries/regions.

Effect of dried yam flour (Dioscorea schimperiana) on cooking quality, digestibility profile and antioxidant potential of wheat based pasta

Yam flour (Dioscorea schimperiana) prepared by traditional (TPYF) and modified (MPYF) processes has been used as an ingredient, to develop bio-functionally enriched pasta. The yam flours have been blended with Durum semolina flour at different levels (10, 20, 30 & 60%) to produce pasta. The cooking quality, antioxidant potential, digestibility profile and sensory profile of the blended pasta have been evaluated. Above all the substituted yam based pasta, the cooking loss was within the permissible level (8%). The β-carotene content of MPYF substituted pasta was significantly higher compared to TPYF samples. The incorporation of yam flour substantially improved total phenolic content (2.9 and 1.7 fold for 60% substituted MPYF and TPYF respectively as compared to control). The same trend was observed with the antioxidant capacity (ABTS - 3.80 and 1.41 fold; RSA - 2.21 and 1.72 fold; FRAP - 14.48 and 11.22 fold respectively for 60% MPYF and TPYF sample as compared to control). The in vitro starch digestibility was reduced significantly among the samples (62.35% in control pasta to 46.41% in 60%MPYF and 50.01% in 60%TPYF samples). The starch profile indicated a significant decrease of rapidly digestible starch (62.63% in control to 43.55% in 60%MPYF and 43.04% in 60%TPYF samples). Sensory evaluation revealed that pasta with up to 30% yam flour was acceptable. Dioscorea schimperiana can be used to improve pasta nutritional quality. For better functional potential, modified process yam flour is suitable.