Reference Physiological Ranges for Serum Biochemical Parameters among Healthy Cameroonians to Support HIV Vaccine and Related Clinical Trials

Background: A valid scientific evaluation of the efficacy of HIV vaccines or antiretroviral drugs includes measurement of changes in physiological parameters of subjects from known established baseline reference ranges. This study was designed to establish reference ranges for biochemical parameters among healthy adult Cameroonians to support planned HIV Vaccine clinical trials and scaling up of ARV drugs among AIDS patients.Methods: After informed consent, blood and urine samples were collected from a total of 576 adult Cameroonians and analyzed for the presence of underlying pathologies that may affect biochemical parameters. Samples from 501 of them were found eligible for the determination of reference biochemical parameters. After complete assay, the data were subjected to both parametric and non parametric statistics for analyses with 2.5 and 97.5 percentiles considered as the lower and upper limits of reference ranges.Results: There were 331(66.1%) males and 170(33.9) females, with 359(71.7%) and 142(28.3) of them residing in the urban and rural areas respectively. Statistically significant differences (P<0.05) were observed in the following biochemical parameters between urban and rural participants: AST, ALT, alkaline phosphatase, creatinine, total protein, albumin, triglyceride, total cholesterol, and the bilirubins. When the data were regrouped into sex, there were statistically significant differences (P<0.05) in the following parameters between males and females: AST, ALT, creatinine, albumin, triglyceride, total cholesterol, and direct bilirubin.Conclusion: The present study shows that sex and geographic location have significant impact on reference physiological biochemical parameters of healthy, adult Cameroonians; hence this should be taken into consideration when monitoring participants either during HIV Vaccine clinical trials or on antiretroviral (ARV) drugs treatment.Key Words: Normal Biochemical Ranges, Health Adult Cameroonians

Reference Physiological Ranges for Serum Biochemical Parameters among Healthy Cameroonians to Support HIV Vaccine and Related Clinical Trials

Background: A valid scienti\ufb01c evaluation of the e\ufb03cacy of HIV vaccines or antiretroviral drugs includes measurement of changes in physiological parameters of subjects from known established baseline reference ranges. This study was designed to establish reference ranges for biochemical parameters among healthy adult Cameroonians to support planned HIV Vaccine clinical trials and scaling up of ARV drugs among AIDS patients. Methods: After informed consent, blood and urine samples were collected from a total of 576 adult Cameroonians and analyzed for the presence of underlying pathologies that may a\ufb00ect biochemical parameters. Samples from 501 of them were found eligible for the determination of reference biochemical parameters. After complete assay, the data were subjected to both parametric and non parametric statistics for analyses with 2.5 and 97.5 percentiles considered as the lower and upper limits of reference ranges. Results: There were 331 (66.1%) males and 170 (33.9) females, with 359 (71.7%) and 142 (28.3%) of them residing in the urban and rural areas respectively. Statistically signi\ufb01cant di\ufb00erences (P<0.05) were observed in the following biochemical parameters between urban and rural participants: AST, ALT, alkaline phosphatase, creatinine, total protein, albumin, triglyceride, total cholesterol, and the bilirubins. When the data were regrouped into sex, there were statistically signi\ufb01cant di\ufb00erences (P<0.05) in the following parameters between males and females: AST, ALT, creatinine, albumin, triglyceride, total cholesterol, and direct bilirubin. Conclusion: The present study shows that sex and geographic location have signi\ufb01cant impact on reference physiological biochemical parameters of healthy, adult Cameroonians; hence this should be taken into consideration when monitoring participants either during HIV Vaccine clinical trials or on antiretroviral (ARV) drugs treatment

Alarming rates of virological failure and HIV-1 drug resistance amongst adolescents living with perinatal HIV in both urban and rural settings: evidence from the EDCTP READY-study in Cameroon

Objectives: Adolescents living with perinatal HIV infection (ALPHI) experience persistently high mortality rates, particularly in resource-limited settings. It is therefore clinically important for us to understand the therapeutic response, acquired HIV drug resistance (HIVDR) and associated factors among ALPHI, according to geographical location. Methods: A study was conducted among consenting ALPHI in two urban and two rural health facilities in the Centre Region of Cameroon. World Health Organization (WHO) clinical staging, self-reported adherence, HIVDR early warning indicators (EWIs), immunological status (CD4 count) and plasma viral load (VL) were assessed. For those experiencing virological failure (VF, VL ≥ 1000 copies/mL), HIVDR testing was performed and interpreted using the Stanford HIV Drug Resistance Database v.8.9-1. Results: Of the 270 participants, most were on nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens (61.7% urban vs. 82.2% rural), and about one-third were poorly adherent (30.1% vs. 35.1%). Clinical failure rates (WHO-stage III/IV) in both settings were < 15%. In urban settings, the immunological failure (IF) rate (CD4  < 250 cells/μL) was 15.8%, statistically associated with late adolescence, female gender and poor adherence. The VF rate was 34.2%, statistically associated with poor adherence and NNRTI-based antiretroviral therapy. In the rural context, the IF rate was 26.9% and the VF rate was 52.7%, both statistically associated with advanced clinical stages. HIVDR rate was over 90% in both settings. EWIs were delayed drug pick-up, drug stock-outs and suboptimal viral suppression. Conclusions: Poor adherence, late adolescent age, female gender and advanced clinical staging worsen IF. The VF rate is high and consistent with the presence of HIVDR in both settings, driven by poor adherence, NNRTI-based regimen and advanced clinical staging

HIV-1 drug resistance testing is essential for heavily-treated patients switching from first- to second-line regimens in resource-limited settings: Evidence from routine clinical practice in Cameroon

BackgroundWith the phase-out of stavudine (d4T), change to first-line regimens with zidovudine (AZT) or tenofovir (TDF) in resource-limited settings (RLS) might increase risks of cross-resistance to nucleos(t) ide reverse transcriptase inhibitors (NRTI). This would restrict the scope of switching to the World Health Organisation (WHO)-recommended standard second-line combinations (SLC) without HIV drug resistance (HIVDR)-testing in routine clinical practice.MethodsAn observational study was conducted among 101 Cameroonian patients (55.4% male, median [IQR] age 34 [10-41] years) failing first-line antiretroviral therapy (ART) in 2016, and stratified into three groups according to NRTIs exposure: exposure to both thymidine analogues AZT and D4T (group-A, n=55); exposure to both TDF and AZT or D4T (group-B, n=22); exposure solely to D4T (group-C, n=24). Protease-reverse transcriptase HIVDR was interpreted using the HIVdb penalty scores (60: high-resistance; 20-59: intermediate-resistance; <20: susceptible). The acceptable threshold for potential-efficacy was set at 80%.ResultsThe median [IQR] CD4, viral RNA, and time on ART, were respectively 129 [29-466] cells/l, 71,630 [19,041-368,000] copies/ml, and 4 [2-5] years. Overall HIVDR-level was 89.11% (90/101), with 83.2% harbouring M184V (high-level 3TC/FTC-resistance) and only 1.98% (2/101) major HIVDR-mutations to ritonavir-boosted protease-inhibitors (PI/r). Thymidine-analogue mutations (TAMs)-1 [T215FY (46.53%), M41L (22.77%), L210W (8.91%)], with cross-resistance to AZT and TDF, were higher compared to TAMs-2 [D67N (21.78%), K70R (19.80%), K219QE (18.81%)]. As expected, K65R was related with TDF-exposure: 0% (0/55) in group-A, 22.72% (5/22) group-B, 4.17% (1/24) group-C (p=0.0013). The potential-efficacy of AZT vs. TDF was respectively 43.64% (24/55) vs. 70.91% (39/55) in group-A (p=0.0038); 63.64% (14/22) vs. 68.28% (15/22) in group-B (p=1.0000); and 37.50% (9/24) vs. 83.33% (20/24) in group-C (p=0.0032). CRF02_AG was the prevailing subtype (63.40%), followed by CRF11.cpx (8.91%), A(1) (7.92%), G (5.94%); without any significant effect of the subtype-distribution on HIVDR (92.2% in CRF02_AG vs. 83.8% in non-AG; p=0.204).ConclusionFirst-line ART-failure exhibits high-level NRTI-resistance, with potential lower-efficacy of AZT compared to TDF. Significantly, using our 80% efficacy-threshold, only patients without NRTI-substitution on first-line could effectively switch to SLC following the WHO-approach. Patients with multiple NRTI-substitutions (exposed to both thymidine-analogues and TDF) on first-line ART would require HIVDR-testing to select active NRTIs for SLC

Pre-treatment drug resistance and HIV-1 genetic diversity in the rural and urban settings of Northwest-Cameroon

Background With the scale-up of antiretroviral therapy (ART), pre-treatment drug resistance (PDR) appears >= 10% amongst ART-initiators in many developing countries, including Cameroon. Northwest region-Cameroon having the second epidemiological burden of HIV infection, generating data on PDR in these geographical settings, will enhance evidence-based decision-making. Objectives We sought to ascertain levels of PDR and HIV-1 clade dispersal in rural and urban settings, and their potential association with subtype distribution and CD4-staging. Methods A cross-sectional study was conducted from February to May 2017 among patients recently diagnosed with HIV-infection and initiating ART at the Bamenda regional Hospital (urban setting) and the Mbingo Baptist hospital (rural setting). Protease and reverse transcriptase sequencing was performed using an in-house protocol and pre-treatment drug resistance mutations were interpreted using StanfordHIVdb.v8.3. Phylogeny was performed for subtype assignation. Results A total of 61 patient sequences were generated from ART initiators (median age: 37 years old; 57.4% female; median CD4 cell count: 184 [IQR: 35-387] in urban vs. 161 [IQR: 96-322] cells/mm(3)in rural). Overall, the level of PDR was 9.8% (6/61). Of note, burden of PDR was almost doubled in urban (12.9% [4/31]) compared to rural setting 6.7% (2/30),p= 0.352). Fifteen (15) PDR mutations were found among four patients the urban settings [6 resistance mutations to NRTIs:[M41L (2), E44D (1), K65R (1), K70E (1), M184V/I (2), K219R (1)] and 6 resistance mutations to NNRTIs: K103N (1), E138A/G (2), V179E (1), M230L (1), K238T (1), P225H (1)] against two (02) mutations found in two patients in the rural setting[2 resistant mutations to NNRTIs: E138A (1) and Y188H (1)]. The rural setting showed more genetic diversity (8 subtypes) than the urban setting (5 subtypes), with CRF02_AG being the most prevalent clade (72.1% [44/61]). Of note, level of PDR was similar between patients infected with CRF02_AG and non-CRF02_AG infected (9.1% [4/44]) vs. 11.8% [2/17]),p= 1.000). Moreover, PDR appeared higher in patients with CD4 cell count <200 cells/mm(3)compared to those with CD4 cell count >= 200 cells/mm(3)(14.7% [5/34]) vs. 3.7% [1/27]),p= 0.214). Conclusions PDR is at a moderate rate in the Northwest region of Cameroon, with higher burden within urban populations. CRF02_AG is the most predominant clade in both urban and rural settings. No effect of HIV molecular epidemiology and CD4-staging on the presence of PDR in patients living in these settings was found. Our findings suggest close monitoring, NNRTI-sparing regimens or sequencing for patients initiating ART, especially in urban settings

Sarpagan bridge enzyme has substrate-controlled cyclization and aromatization modes

International audienceCyclization reactions that create complex polycyclic scaffolds are hallmarks of alkaloid biosynthetic pathways. We present the discovery of three homologous cytochrome P450s from three monoterpene indole alkaloid-producing plants (Rauwolfia serpentina, Gelsemium sempervirens and Catharanthus roseus) that provide entry into two distinct alkaloid classes, the sarpagans and the β-carbolines. Our results highlight how a common enzymatic mechanism, guided by related but structurally distinct substrates, leads to either cyclization or aromatization