Collins Otieno Asweto

1H NMR-based metabolomics study on repeat dose toxicity of fine particulate matter in rats after intratracheal instillation

Systemic metabolic effects and toxicity mechanisms of ambient fine particulate matter (PM2.5) remain uncertain. In order to investigate the mechanisms in PM2.5 toxicity, we explored the endogenous metabolic changes and possible influenced metabolic pathways in rats after intratracheal instillation of PM2.5 by using a 1H nuclear magnetic resonance (NMR)-based metabolomics approach. Liver and kidney histopathology examinations were also performed. Chemical characterization demonstrated that PM2.5 was a complex mixture of elements. Histopathology showed cellular edema in liver and glomerulus atrophy of the PM2.5 treated rats. We systematically analyzed the metabolites changes of serum and urine in rats using 1H NMR techniques in combination with multivariate statistical analysis. Significantly reduced levels of lactate, alanine, dimethylglycine, creatine, glycine and histidine in serum, together with increased levels of citrate, arginine, hippurate, allantoin and decreased levels of allthreonine, lactate, alanine, acetate, succinate, trimethylamine, formate in urine were observed of PM2.5 treated rats. The mainly affected metabolic pathways by PM2.5 were glycine, serine and threonine metabolism, glyoxylate and dicarboxylate metabolism, citrate cycle (TCA cycle), nitrogen metabolism and methane metabolism. Our study provided important information on assessing the toxicity of PM2.5 and demonstrated that metabolomics approach can be employed as a tool to understand the toxicity mechanism of complicated environmental pollutants.

Glycan Biomarkers for Rheumatoid Arthritis and Its Remission Status in Han Chinese Patients.

Rheumatoid arthritis (RA), a systemic, chronic, and progressive inflammatory autoimmune disease, affects up to 1.0% of the world population doubling mortality rate of patients and is a major global health burden. Worrisomely, we lack robust diagnostics of RA and its remission status. Research with the next-generation biomarker technology platforms such as glycomics offers new promises in this context. We report here a clinical case-control study comprising 128 patients suffering from chronic RA (80.22% in remission, 19.78% active clinically) and 195 gender- and age-matched controls, with a view to the putative glycan biomarkers of RA as well as its activity or remission status in Han Chinese RA patients. Hydrophilic interaction liquid chromatography-ultra-performance liquid chromatography (HILIC-UPLC) was used for the analysis of IgG glycans. The regression model identified the glycans that predict RA status, while a receiver operating characteristic (ROC) curve analysis validated the sensitivity and prediction power. Among the total 24 glycan peaks (GP1-GP24), ROC analysis showed only GP1 prediction to be highly sensitive with an area under the curve (AUC) = 0.881. Even though GP21 and GP22 could predict active status among the RA cases (p < 0.05), they had lower sensitivity of prediction with an AUC = 0.658. Taken together, these observations suggest that GP1 might have potential as a putative biomarker for RA in the Han Chinese population, while the change in IgG glycosylation shows association with the RA active and remission states. To the best of our knowledge, this is the first glycomics study with respect to disease activity and remission states in RA.

Genome-wide transcriptional analysis of cardiovascular-related genes and pathways induced by PM2.5 in human myocardial cells

Air pollution has been a major environment-related health threat. Most of the studies on PM2.5 toxicity have verified on the cardiovascular system and endothelial cells. However, researches on PM2.5-induced myocardial-related toxicity are limited. This study aims to fully understand the toxic effects of PM2.5 on human myocardial cell (AC16) and explore its molecular mechanism based on microarray analysis and bioinformatics analysis. Microarray data analysis manifested that PM2.5-induced toxicity affected expression of 472 genes compared with the control group, including 166 upregulated genes and 306 downregulated genes in human myocardial (AC16) cells. GO analysis showed that cellular processes such as immune response, cell maturation, embryonic heart tube morphogenesis, cellular response to electrical stimulus, skeletal muscle tissue regeneration, and negative regulation of signal transduction were upregulated, while regulation of transcription (DNA-dependent), rhythmic process, protein destabilization apoptotic process, and innate immune response were downregulated. The pathway analysis indicates that cell signaling pathways such as cytokine-cytokine receptor interaction, NF-κB signaling pathway, chemokine signaling pathway, endocrine and other factor-regulated calcium reabsorption, HTLV-I infection, and cell adhesion molecules (CAMs) were upregulated, while the TGF-β signaling pathway was downregulated. In addition, Signal-net showed that the TUBA4A, ADRBK2, BRIX1, SMC4, EIF5B, PRMT1, ATG4B, and NDC80 genes were significantly decreased, while the expression of the KRT6B gene was markedly increased compared with the control group. All the genes were verified by qRT-PCR. This study had provided new bioinformatics evidences in PM2.5-induced myocardial tissue toxicity which is necessary for further cardiovascular system toxicity studies.

Telomere Length and Accelerated Biological Aging in the China Suboptimal Health Cohort: A Case–Control Study

Suboptimal health status (SHS) has been linked to cardiovascular risk factors, psychosocial stress, and unhealthy lifestyle. These factors also contribute to the shortening of telomere length (TL). A case-control study was conducted to examine the association between subjective health measures of SHS from the behavior perspective and also objective measures of TL at molecular level. SHS (cases = 294) was matched by age, sex, and body mass index with ideal health (controls = 294) using a propensity score matching method. Suboptimal health status questionnaire-25 (SHSQ-25) was used in the community-based health survey. A quantitative polymerase chain reaction was used to measure relative telomere length (RTL). Shorter RTL was found among the SHS group compared to the ideal health group (p < 0.05). SHS was almost four times likely to be in the first quartile (odds ratio [OR] = 3.81; 95% confidence interval [CI] 2.21-6.56), almost thrice in second quartile (OR = 2.84; 95% CI 1.65-4.90), and almost twice likely to be in the third quartile (OR = 1.71; 95% CI 1.00-2.94) compared to the fourth quartile (the longest) of RTL after adjusting for socioeconomic, dietary intake, anthropometric, blood pressure, and biochemistry variables (p < 0.05). Notably, SHS score was negatively correlated with RTL (r = -0.218, p < 0.05). Our study confirms an association between SHS and short RTL. Combination of subjective (SHS) and objective (RTL) measures is a novel tool for health aging investigation. Therefore, SHSQ-25 could be used as a screening tool for measuring biological aging in low-income countries at community level where the expensive technique for RTL measurement is not applicable.

Combined effect of silica nanoparticles and benzo[a]pyrene on cell cycle arrest induction and apoptosis in human umbilical vein endothelial cells

Particulate matter (PM) such as ultrafine particulate matter (UFP) and the organic compound pollutants such as polycyclic aromatic hydrocarbon (PAH) are widespread in the environment. UFP and PAH are present in the air, and their presence may enhance their individual adverse effects on human health. However, the mechanism and effect of their combined interactions on human cells are not well understood. We investigated the combined toxicity of silica nanoparticles (SiNPs) (UFP) and Benzo[a]pyrene (B[a]P) (PAH) on human endothelial cells. Human umbilical vascular endothelial cells (HUVECs) were exposed to SiNPs or B[a]P, or a combination of SiNPs and B[a]P. The toxicity was investigated by assessing cellular oxidative stress, DNA damage, cell cycle arrest, and apoptosis. Our results show that SiNPs were able to induce reactive oxygen species generation (ROS). B[a]P, when acting alone, had no toxicity effect. However, a co-exposure of SiNPs and B[a]P synergistically induced DNA damage, oxidative stress, cell cycle arrest at the G2/M check point, and apoptosis. The co-exposure induced G2/M arrest through the upregulation of Chk1 and downregulation of Cdc25C, cyclin B1. The co-exposure also upregulated bax, caspase-3, and caspase-9, the proapoptic proteins, while down-regulating bcl-2, which is an antiapoptotic protein. These results show that interactions between SiNPs and B[a]P synergistically potentiated toxicological effects on HUVECs. This information should help further our understanding of the combined toxicity of PAH and UFP.

The Malaysian health care system: Ecology, plans, and reforms.

Malaysia is on its way to achieving developed nation status in the next 4 years. Currently, Malaysia is on track for three Millennium Development Goals (MDG1, MDG4, and MDG7). The maternal mortality rate, infant mortality rate, and mortality rate of children younger than 5 years improved from 25.6% (2012) to 6.6% (2013), and 7.7% (2012) per 100,000 live births, respectively whereas immunization coverage for infants increased to an average of 90%. As of 2013 the ratio of physicians to patients improved to 1:633 while the ratio of health facilities to the population was 1:10,272. The current government administration has proposed a reform in the form of the 10th Malaysian Plan coining the term “One Care for One Malaysia” as the newly improved and reorganized health care plan, where efficiency, effectiveness, and equity are the main focus. This review illustrates Malaysia’s transition from pre-independence to the current state, and its health and socioeconomic achievement as a country. It aims to contribute knowledge through identifying the plans and reforms by the Malaysian government while highlighting the challenges faced as a nation.

Integration of community health workers into health systems in developing countries: Opportunities and challenges

Background Developing countries have the potential to reach vulnerable and underserved populations marginalized by the country’s health care systems by way of community health workers (CHWs). It is imperative that health care systems focus on improving access to quality continuous primary care through the use of CHWs while paying attention to the factors that impact on CHWs and their effectiveness. Objective To explore the possible opportunities and challenges of integrating CHWs into the health care systems of developing countries. Methods Six databases were examined for quantitative, qualitative, and mixed-methods studies that included the integration of CHWs, their motivation and supervision, and CHW policy making and implementation in developing countries. Thirty-three studies met the inclusion criteria and were double read to extract data relevant to the context of CHW programs. Thematic coding was conducted and evidence on the main categories of contextual factors influencing integration of CHWs into the health system was synthesized. Results CHWs are an effective and appropriate element of a health care team and can assist in addressing health disparities and social determinants of health. Important facilitators of integration of CHWs into health care teams are support from other health workers and inclusion of CHWs in case management meetings. Sustainable integration of CHWs into the health care system requires the formulation and implementation of polices that support their work, as well as financial and nonfinancial incentives, motivation, collaborative and supportive supervision, and a manageable workload. Conclusions For sustainable integration of CHWs into health care systems, high-performing health systems with sound governance, adequate financing, well-organized service delivery, and adequate supplies and equipment are essential. Similarly, competent communities could contribute to better CHW performance through sound governance of community resources, promotion of inclusiveness and cohesion, engagement in participatory decision making, and mobilization of local resources for community welfare.

Cellular pathways involved in silica nanoparticles induced apoptosis: A systematic review of in vitro studies

Silica nanoparticles (SiNPs) have been found to pass through biological barriers and get distributed in the human body. They induce cell apoptosis via various mechanisms in body organs. To understand these mechanisms, we carried out systematic review of in vitro studies on SiNPs-induced cell apoptosis. Office of Health Assessment and Translation approach for Systematic Review and Evidence Integration was used to identify 14 studies dating from the year 2000 to current. Four studies showed an increase in DNA damage, cell cycle arrest, proapoptotic factors and decrease in antiapoptotic factors resulting to apoptosis. Eight studies showed induction of mitochondrial dysfunction, Bax upregulation, Bcl-2 downregulation, and caspase-3, -7, -9 activities increase. Increase in FADD, TNFR1 and Bid proteins was observed in one study, while the other NO production and caspase-3 activity was increased. These studies found the potency of SiNPs to induce cell apoptosis through DNA damage, mitochondrial, tumor necrosis factor, and nitric oxide related pathways.

Low-dose combined exposure of nanoparticles and heavy metal compared with PM2.5 in human myocardial AC16 cells

The co-exposure toxicity mechanism of ultrafine particles and pollutants on human cardiovascular system are still unclear. In this study, the combined effects of silica nanoparticles (SiNPs) and/or carbon black nanoparticles (CBNPs) with Pb(AC)2 compared with particulate matter (PM)2.5 were investigated in human myocardial cells (AC16). Our study detected three different combinations of SiNPs and Pb(AC)2, CBNPs and Pb(AC)2, and SiNPs and CBNPs compared with PM2.5 at low-dose exposure. Using PM2.5 as positive control, our results suggested that the combination of SiNPs and Pb(AC)2/CBNPs could increase the production of reactive oxygen species (ROS), lactate dehydrogenase leakage (LDH), and malondialdehyde (MDA) and decrease the activities of superoxide dismutase (SOD) and glutathione (GSH); induce inflammation by the upregulation of protein CRP and TNF-α, and apoptosis by the upregulation of protein caspase-3, caspase-9, and Bax while the downregulation of protein Bcl-2; and trigger G2/M phase arrest by the upregulation of protein Chk2 and downregulation of protein Cdc2 and cyclin B1. In addition, the combination of CBNPs and Pb(AC)2 induced a significant increase in MDA and reduced the activities of ROS, LDH, SOD, and GSH, with G1/S phase arrest via upregulation of Chk1 and downregulation of CDK6 and cyclin D1. Our data suggested that the additive interaction and synergistic interaction are the major interaction in co-exposure system, and PM2.5 could trigger more severe oxidative stress, G2/M arrest, and apoptosis than either co-exposure or single exposure.

Gene expression profiles and bioinformatics analysis of human umbilical vein endothelial cells exposed to PM2.5

Cardiovascular system is demonstrated the main target of PM2.5 and the objective of this study was to explore the toxic effect and molecular mechanisms caused by PM2.5 in primary human umbilical vein endothelial cells (HUVECs) using microarray and bioinformatics analysis. The results showed that 591 genes were differentially expressed triggered by PM2.5, of which 174 genes were down-regulated, while 417 genes were up-regulated. Gene ontology analysis revealed that PM2.5 caused significant changes in gene expression patterns, including response to stimuli, immune response, and cellular processes. Pathway analysis and Signal-net analysis suggested that endocytosis, chemokine signaling pathway, RNA transport, protein processing in endoplasmic reticulum (ER) and autophagy regulation were the most critical pathways in PM2.5-induced toxicity in HUVECs. Moreover, gene expression confirmation of LIF, BCL2L1, CSF3, HMOX1, RPS6, PFKFB, CAPN1, HSPBP1, MOGS, PREB, TUBB2A, GABARAP by qRT-PCR indicated that endocytosis might be involved in the cellular uptake of PM2.5 by forming phagosomes, and subsequently inflammation, hypoxia and ER stress was occurred, which finally activated autophagy after PM2.5 exposure in HUVECs. In summary, our data can serve as fundamental research clues for further studies of PM2.5-induced toxicity in HUVECs.