Available online on 15.03.2024 at http://jddtonline.info

Journal of Drug Delivery and Therapeutics

Open Access to Pharmaceutical and Medical Research

Copyright  © 2024 The   Author(s): This is an open-access article distributed under the terms of the CC BY-NC 4.0 which permits unrestricted use, distribution, and reproduction in any medium for non-commercial use provided the original author and source are credited

Open Access  Full Text Article                                                                                                                                                      Research Article

Evaluation of Interleukin 4, High Sensitivity C-Reactive Protein and Activity of Alanine Transaminase Among Cooks in Nnewi 

*Augustine Chinedu Ihim ¹, Joy Chiemeka Iloka ¹, Christian Ejike Onah ¹, Patrick Chinedu Obi ², N Osakue ¹, Ejiofor Christopher Agbo ³_, JC Awalu ⁴

¹ Department of Medical Laboratory Science, Faculty of Health Sciences and Technology, Nnamdi Azikiwe University, Awka Anambra, Nigeria

² Department of Internal Medicine, Federal University Teaching Hospital Owerri, Imo State, Nigeria

³ Department of Medical Laboratory Services, Federal Medical Centre Umuahia, Abia state, Nigeria

⁴ Department of Medical Laboratory Science, Evangel Akaeze Ebonyi State, Nigeria

INTRODUCTION

Soot is the byproduct of incomplete combustion of organic compounds ¹. Soot refers to carbonaceous particles produced by the incomplete or pyrolytic burning of hydrocarbon fuels ². Both human-induced (such as traffic, household heating, and industrial) and naturally occurring (such as wildfire) combustion processes emit soot, or its associated substances black carbon (BC) and elemental carbon (EC) ³. Around the world, soot is recognized as a major air pollutant with Africa ranking high among the highest emitters ¹. Global warming is caused by soot emissions into the atmosphere ⁴. It is believed that long-lived greenhouse gases (GHGs) and soot particulate matter (PM), which is mostly caused by incomplete engine combustion, are the two main climate change forcing agents ⁵. The tiny size of soot particles—which are also found in PM10 and PM2.5 dust—allows them to pass through the body's protective barrier and enter not just the lungs but occasionally the skin as well ⁶. Soot particles easily penetrate the body tissues causing respiratory diseases, like asthma, skin disorders, reproductive problems, and cardiovascular diseases ^7,1. The primary organic substance in soot, polycyclic aromatic hydrocarbons (PAHs), has also been linked to mutagenic and carcinogenic consequences ². Several past studies have described soot as a carcinogen and linked it to different kinds of cancer ^8,9,10. PM2.5 is known to cause oxidative stress and inflammation in the respiratory tract, which aggravates long-term chronic diseases like cancer and asthma as well as respiratory and cardiovascular problems ¹¹. Many chronic and acute disorders, including chronic respiratory conditions, heart disease, hypertension, and ischemic stroke, are strongly correlated with long-term exposure to particulate matter (PM) ¹².  Also, ambient PM2.5 exposure may be a substantial risk factor for the progression of non-alcoholic fatty liver disease (NAFLD) ¹³, which has been linked to an increase in the prevalence and mortality of liver cancer. Research claimed that there is a higher death rate from ischemic heart disease among chimney sweeps as well as a higher incidence of myocardial infarction ¹⁴. Also, by starting and fostering the formation of atherosclerosis, the primary cause of most cardiovascular disorders, exposure to soot particulate matter increases the chance of developing cardiovascular disease ¹⁵. In a Swedish retrospective cohort research, working as a chimney sweep was linked to a higher chance of developing liver cancer ¹⁶. It was observed in a study that PM2.5 caused hepatic fibrosis in a mouse model and had a direct negative impact on the liver's health ¹⁷. Long-term exposure to ambient particulate matter has been linked to an increased risk of metabolic dysfunction-associated fatty liver disease (NAFLD), according to a study conducted in southwest China ¹⁸. Also, according to a study in the Niger Delta region of Nigeria, the serum activities of liver enzymes (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase) were significantly increased in women exposed to air pollution caused by gas flaring ¹⁹.

Interleukin 4 (IL-4) is a pleiotropic cytokine that regulates immunological responses linked to lymphocyte development and survival factors ²⁰. As a pleiotropic cytokine, interleukin-4 (IL-4) is primarily recognized for its function in type 2 immunity ²¹, which guarantees a number of host-protective functions, including wound healing and helminth parasite resistance ²². During allergic reactions, type 2 T helper (Th2) cells secrete the important cytokine interleukin-4 (IL-4), which directs the immune system's response ²³. The approximately 10 kb-sized IL4 gene, which codes for interleukin 4(IL-4), has four exons and is located on chromosome 5q31.1 ²⁴. IL-4 induces the immunoglobulin (Ig) class switching to IgG1 and IgE in B cells, differentiates naive CD4 T cells into Th2 cells in T cells, and triggers alternative macrophage activation in macrophages ²⁵. C reactive protein, a homopentameric acute phase inflammatory protein was first discovered in 1930 when Tillet and Francis studied sera of patients with the acute stage of pneumococcus infection. It was named c reactive protein due to its reaction with the capsular(c)-polysaccharide of pneumococcus ²⁶. Hepatocytes produce the acute phase protein known as C reactive protein (CRP) in response to pro-inflammatory cytokines during inflammatory and infectious processes ²⁷. CRP levels are elevated in a variety of inflammatory disorders, and its serum concentration is commonly measured to gauge the severity of systemic inflammation. High-sensitivity CRP assays (hs-CRP) have been developed recently for sensitive CRP quantification. These assays are particularly valuable because they may indicate the presence of low-grade inflammatory lesions as they can detect little fluctuations in serum CRP levels within the range of normal limits ²⁸. Hs-CRP is employed as a predictive marker of the likelihood of developing heart disease and stroke ²⁹. Also, hsCRP testing is used to determine the prognosis of coronary stent thrombosis, as well as cardiac failure, atrial fibrillation, hypertension, and valve dysfunction ³⁰. The liver's gluconeogenesis and cellular nitrogen metabolism are both aided by the enzyme alanine transaminase (ALT), which catalyzes the conversion of alanine and α-ketoglutarate to pyruvate and glutamate ³¹. The coenzyme pyridoxal 5'-phosphate, often known as vitamin B6, is required for this reaction ³².  Since ALT is mostly found in the cytoplasm of hepatocytes, an increase in its concentration in the serum indicates that the membranes of the liver cells had been damaged ³³. Many people are exposed to soot daily through their occupation without any knowledge of what such exposures could mean to their health. This research evaluated the effect of soot exposure on cooks to validate the possible health effects.

MATERIALS AND METHODS

All the reagents were commercially obtained and the manufacturer’s Standard operation procedures (SOP) were strictly adhered to. This study was carried out in Nnewi, Nnewi North local government area of Anambra State, in the South-East region of Nigeria.

Study Participants                                  

G* Power software version 3.0.10 (Universitat Dusseldorf, Germany) was used to determine the sample size. Using an alpha of 0.05, a power of 0.80, and a medium effect size of 0.4, the power to identify an appropriate sample size was calculated. Based on these, the estimated sample size of 80 can detect differences of 0.4 at a 0.05 level of significance with 80% accuracy. A total sample size of 90 was employed for this study to account for potential attrition. Ninety participants within the age range of 12 – 60 years were enlisted and the participants were divided into two groups as follows; Group one (1) comprising of forty-five (45) participants who were exposed to soot (the test group). Group two (2) comprising of forty-five (45) participants who were not exposed to soot (the control group). A questionnaire to determine the socio-demographic information of the participants and frequency of exposure to soot was used. The ethical approval for this research was obtained from the ethics committee of the Faculty of Health Science and Technology, College of Health Sciences, Nnamdi Azikiwe University, Nnewi Campus with the protocol number: FHST/REC/023/00252. Consent for the study was sought from and signed by the participants before the study. Participants residing outside Nnewi, those who were smokers or had chronic diseases, those outside the age range of 12-60, and those who were not willing to be part of the study were excluded. Five milliliters (5ml) of venous blood was aseptically drawn from each participant’s ante-cubital vein using a plastic syringe and dispensed in a plain tube. Following centrifugation at 4000rpm for 5 minutes, the serum was obtained for the assessment of interleukin 4, High sensitivity C reactive protein, and activity of alanine transaminase. The samples were kept at a temperature of -20^oC before the biochemical examination.

Statistical analysis

Statistical Package for Social Science (SPSS) (version 26.0) for Windows, SPSS Inc. Chicago, USA, was used to analyze the data. Data was expressed as Mean ± standard deviation (SD). The differences in parameters studied between the test and the control groups were evaluated using an independent t–test and Pearson’s correlation coefficient to determine the association between the serum levels of Interleukin 4, High sensitivity C-reactive protein, and the activity of alanine transaminase with BMI, Systolic blood pressure and Diastolic blood pressure. Statistical significance was set at p-value < 0.05.

RESULTS

Table 1. The mean values of the BMI and blood pressure of participants exposed to soot (Test Group) and participants not exposed to soot (Control Group) (Mean ± SD).

The mean value of BMI (24.80 ± 4.12) was significantly higher in participants exposed to soot when compared to participants not exposed to soot (22.18 ± 2.72) (p<0.05). However, there was no significant difference in the mean value of blood pressure of participants exposed to soot compared to participants not exposed to soot (p>0.05).

Table 1. The mean values of the BMI and blood pressure of participants exposed to soot (Test Group) and participants not exposed to soot (Control Group) (Mean ± SD).

*Statistically significant at P<0.05                   BMI= Body Mass Index, SBP= Systolic Blood Pressure, DBP= Diastolic Blood Pressure

Table 2. The mean serum levels of Interleukin 4, High Sensitivity C-Reactive Protein and Activity of Alanine Transaminase of participants exposed and not exposed to soot (Mean ± SD).

The mean serum activity of alanine transaminase (9.30 ± 0.28) was significantly lower in the participants exposed to soot when compared to participants not exposed to soot (9.48 ± 0.37) (p<0.05). However, there was no significant difference in the mean serum levels of Interleukin 4 and high sensitivity C-reactive protein of participants exposed to soot compared to participants not exposed to soot (p>0.05).

Table 2: The mean serum levels of Interleukin 4, High Sensitivity C-Reactive Protein and Alanine Transaminase of participants exposed and not exposed to soot (Mean ± SD).

*Statistically significant at P<0.05                 IL-4= Interleukin 4, Hs-CRP= High Sensitivity C-Reactive Protein, ALT= Alanine Transaminase

Table 3. Correlation of the serum levels of Interleukin 4, High sensitivity C-reactive protein, and Activity of Alanine Transaminase with the BMI, Systolic blood pressure, and Diastolic blood pressure of participants exposed to soot.

There was no correlation observed between the serum levels of Interleukin 4 and high sensitivity C-reactive protein and activity of alanine transaminase and the BMI, systolic blood pressure and diastolic blood pressure in participants exposed to soot.

*Statistically significant at P<0.05                 IL-4= Interleukin 4, Hs-CRP= High Sensitivity C-Reactive Protein, ALT= Alanine Transaminase

DISCUSSION                       

The majority of chefs are unaware of how exposure to soot or particulate matter (PM) might negatively impact their health. Unfortunately, most homes and kitchens in Nigeria, particularly in Nnewi, lack chimneys or pipes that discharge kitchen smoke into the atmosphere, which increases the concentration of soot and makes it easier for cooks to inhale ³⁴. There was no significant difference in the blood pressure of cooks exposed to soot compared with the control (p>0.05). This was expected since every participant was in good health. However, a significantly higher difference was seen in the mean value of BMI of cooks exposed to soot compared to the control. This could be because the participants were not height and weight-matched. A non-significant difference was observed in the mean serum level of interleukin 4 in participants exposed to soot compared to the control (p>0.05). This is in contrast with the findings of ³⁵ which found a significant difference in IL-4 levels in chronic obstructive pulmonary disease (COPD) patients exposed to air pollution compared to control. Additionally, ³⁶ observed a significant difference in the level of Interleukin 4 in Allergic Asthma (AA) patients exposed to allergic substances compared to the control. The difference in the results could be a result of the difference in the study design used for the studies.

A nonsignificant difference in the mean serum level of high sensitivity C-reactive protein (Hs-CRP) in cooks exposed to soot compared to control (p<0.05) was observed in this research study. This result is consistent with the study by ³⁷, which reported no significant difference in the level of C-reactive protein in chimney sweeps exposed to polycyclic aromatic hydrocarbons (PAH) through soot. Additionally, a non-significant association between C-reactive protein and long-term air pollution was seen in a German study on C-reactive protein and long-term air pollution ³⁸. However, this study result varies from that of ³⁹ which found the level of environmental carbon monoxide to be significantly associated with high sensitivity C-reactive protein in Peritoneal dialysis patients. An older Chinese adult cohort study by ⁴⁰ also found a significant association of evaluated air pollutants with elevations in high-sensitivity C-reactive protein. Additionally, ⁴¹ reported a significant difference in the mean serum level of high-sensitivity C-reactive protein (hs-CRP) in vehicle inspectors exposed to particulate matter compared to the control. The contrasts observed in the works could be because of the difference in the study design, method of analysis, statistical approach, confounding variables, and number of participants involved in the studies.

A significantly lower difference in the activity of alanine transaminase was seen in participants exposed to soot compared to the control. The statistical significance of alanine transaminase in this study did not infer clinical significance since the mean serum activity in the participants remained within the reference range. This result differs from the findings of ⁴² where there was a significantly higher difference in the mean serum activity of ALT in participants exposed to air pollution in areas near oil drilling sites since birth compared with control. In a study to determine the serum activities of liver enzymes in cooks exposed to soot, ³⁴ found the serum activity of alanine transaminase to be significantly higher in the test group compared to control. Additionally, ⁴³ in a Taiwanese population study saw an association between long-term exposure to particulate matter and an increase in the activities of liver enzymes, including alanine transaminase. In an animal study to investigate the health impacts of chronic exposure to urban air on the liver, heart, and serum risk biomarkers, ⁴⁴ reported a significant increase in the activities of liver enzymes in mice exposed to urban air compared to control.

This research observed no association between the levels of Interleukin 4, High sensitivity C-reactive protein, and activity of alanine transaminase and the body mass index, systolic blood pressure, and diastolic blood pressure of cooks exposed to soot. This agrees with the work of ³⁴ on the effect of exposure to soot on the activities of liver enzymes, which observed no relationship between the activity of alanine transaminase and the BMI, systolic blood pressure, and diastolic blood pressure. No statistically significant correlation was seen between BMI and interleukin 4 (IL-4) ⁴⁵. Also, a study to evaluate serum high-sensitivity C-reactive protein levels, as a marker of inflammation, in a large sample of the Iranian population without a history of cardiovascular or inflammatory disease and cancer, found no significant independent correlation between hs-CRP and blood pressure ⁴⁶.

CONCLUSION 

The levels of Interleukin 4 and high sensitivity C-reactive protein did not change significantly, according to this study. Although it did not necessarily imply any clinical importance, a significantly lower difference in alanine transaminase activity was also discovered. Consequently, in this study, it is possible that soot exposure does not increase the risk of developing systemic inflammation, cardiovascular disease, or liver disease. 

Acknowledgments:

The authors would like to pay their most profound gratitude to the management and staff of Nnamdi Azikiwe University Teaching Hospital, Nnewi, and Reene Medical Diagnostic Laboratory, Awada, Anambra State, for the laboratory analyses of all biochemical parameters.

Conflicts of Interest:

None declared

Author contributions:

ACI, JCI, and PCO

conceived and designed the research proposal. CEO and ON performed sample

collection, experiments, and data analysis. ACI, ECA, and AJC contributed to

the final version of the manuscript. All authors have read and approved the

final manuscript.

Data availability

The data used to support the findings of this study are available from the corresponding author upon reasonable request.

Funding: 

No funding sources.

Ethical approval:

The study was approved by the Ethics Committee of the Faculty of Health Sciences and Technology, Nnamdi Azikiwe University, Nnewi, Anambra State, Nigeria FHST/REC/023/00252

REFERENCES

1. Nyebuchi J, Achonnwo KC, Roseline E, Josephine O, “Soot and carcinogenesis in Rivers State” J. Cancer Tumor Int, 2022;12(2):16-22. https://doi.org/10.9734/jcti/2022/v12i230172
2. Wang Y, Chung SH, "Soot formation in laminar counterflow flames" Prog. Energy Combust. Sci., 2019; 74:152-238.  https://doi.org/10.1016/j.pecs.2019.05.003
3. Offer S, Hartner E, Di Bucchianico S, Bisig C, Bauer S, Pantzke J, Zimmermann EJ, Cao X, Binder S, Kuhn E, Huber A, Jeong S, Käfer U, Martens P, Mesceriakovas A, Bendl J, Brejcha R, Buchholz A, Gat D, Hohaus T, Rastak N, Jakobi G, Kalberer M, Kanashova T, Hu Y, Ogris C, Marsico A, Theis F, Pardo M, Gröger T, Oeder S, Orasche J, Paul A, Ziehm T, Zhang ZH, Adam T, Sippula O, Sklorz M, Schnelle-Kreis J, Czech H, Kiendler-Scharr A, Rudich Y, Zimmermann R, "Effect of Atmospheric Aging on Soot Particle Toxicity in Lung Cell Models at the Air-Liquid Interface: Differential Toxicological Impacts of Biogenic and Anthropogenic Secondary Organic Aerosols (SOAs)" Environ Health Perspect. 2022; 130(2):27003. https://doi.org/10.1289/EHP9413
4. Martin JW, Pascazio L, Menon A, Akroyd J, Kaiser K, Schulz F, Commodo M, D'Anna A, Gross L, Kraft M, "π-Diradical Aromatic Soot Precursors in Flames" J Am Chem Soc. 2021; 143(31):12212-12219.  https://doi.org/10.1021/jacs.1c05030
5. Zhao F, Yang W, Yu W, "A progress review of practical soot modelling development in diesel engine combustion" J. Traffic Transp. Eng. (Engl. Ed.), 2020; 7(3):269-281. https://doi.org/10.1016/j.jtte.2020.04.002
6. Szatyłowicz E, Skoczko I, "Evaluation of the PAH content in soot from solid fuels combustion in low power boilers" Energies, 2019; 12(22):4254. https://doi.org/10.3390/en12224254
7. Owhor GA, Rejoice Chigbo C, Chinemelum Iwendi G, Ogunkola I, germanos O, Ateb R, Iriagbonse Uba B, “Black Soot: A Threat to the Environment and Population’s Health in Rivers State Nigeria” The Nig Health J. 2023; 23(1):577-9. https://www.tnhjph.com/index.php/tnhj/article/view/631
8. Niranjan R, Thakur AK, "The Toxicological Mechanisms of Environmental Soot (Black Carbon) and Carbon Black: Focus on Oxidative Stress and Inflammatory Pathways" Front Immunol. 2017; 8:763.  https://doi.org/10.3389/fimmu.2017.00763
9. Yakubu OH, "Particle (soot) pollution in Port Harcourt Rivers State, Nigeria—double air pollution burden? Understanding and tackling potential environmental public health impacts" Environments, 2018; 5(1):2. https://doi.org/10.3390/environments5010002
10. Dandajeh HA, Ladommatos N, Hellier P, "Influence of unsaturation of hydrocarbons on the characteristics and carcinogenicity of soot particles" J Anal Appl Pyrolysis. 2020; 151:104900.  https://doi.org/10.1016/j.jaap.2020.104900
11. Al Housseiny H, Singh M, Emile S, Nicoleau M, Wal RLV, Silveyra P, "Identification of Toxicity Parameters Associated with Combustion Produced Soot Surface Chemistry and Particle Structure by in Vitro Assays" Biomedicines. 2020; 8(9):345. https://doi.org/10.3390/biomedicines8090345
12. Fang Q, Zhao Q, Chai X, Li Y, Tian S, "Interaction of industrial smelting soot particles with pulmonary surfactant: Pulmonary toxicity of heavy metal-rich particles" Chemosphere. 2020; 246:125702.  https://doi.org/10.1016/j.chemosphere.2019.125702
13. Li R, Zhang M, Wang Y, Yung KKL, Su R, Li Z, Zhao L, Dong C, Cai Z, "Effects of sub-chronic exposure to atmospheric PM2.5 on fibrosis, inflammation, endoplasmic reticulum stress and apoptosis in the livers of rats" Toxicol Res (Camb). 2018; 7(2):271-282.  https://doi.org/10.1039/c7tx00262a
14. Alhamdow A, Lindh C, Albin M, Gustavsson P, Tinnerberg H, Broberg K, "Cardiovascular Disease-Related Serum Proteins in Workers Occupationally Exposed to Polycyclic Aromatic Hydrocarbons" Toxicol Sci. 2019; 171(1):235-24. https://doi.org/10.1093/toxsci/kfz142
15. Leonard E, Aminuddin M, "The effect of soot particulate towards vascular cell adhesion molecule-1 (Vcam-1) expression in the mechanism of cardiovascular system disruption" Med. Legal Update. 2020; 20(2):830-835.
16. VoPham T, "Environmental risk factors for liver cancer and nonalcoholic fatty liver disease" Curr Epidemiol Rep. 2019; 6(1):50-66.  https://doi.org/10.1007/s40471-019-0183-2
17. Zheng Z, Zhang X, Wang J, Dandekar A, Kim H, Qiu Y, Xu X, Cui Y, Wang A, Chen LC, Rajagopalan S, Sun Q, Zhang K, "Exposure to fine airborne particulate matters induces hepatic fibrosis in murine models" J Hepatol. 2015; 63(6):1397-404. https://doi.org/10.1016/j.jhep.2015.07.020
18. Guo B, Guo Y, Nima Q, Feng Y, Wang Z, Lu R, Baimayangji, Ma Y, Zhou J, Xu H, Chen L, Chen G, Li S, Tong H, Ding X, Zhao X; China Multi-Ethnic Cohort (CMEC) collaborative group, "Exposure to air pollution is associated with an increased risk of metabolic dysfunction-associated fatty liver disease" J Hepatol. 2022; 76(3):518-525.  https://doi.org/10.1016/j.jhep.2021.10.016
19. Nwaogu LA, Onyeze GOC, Nwabueze RN, Adieze IE, "Changes in Liver, Kidney and Atherogenic Indices of Women in Ebocha, Niger-Delta, Nigeria due to Gas Flaring". J. Phys. Sci. Environ. Stud. 2021; 7(5):59-64.  https://doi.org/10.36630/jpses_21011
20. Kwaśniak K, Czarnik-Kwaśniak J, Maziarz A, Aebisher D, Zielińska K, Karczmarek-Borowska B, Tabarkiewicz J, "Scientific reports concerning the impact of interleukin 4, interleukin 10 and transforming growth factor β on cancer cells" Cent Eur J Immunol. 2019; 44(2):190-200. https://doi.org/10.5114/ceji.2018.76273
21. Gärtner Y, Bitar L, Zipp F, Vogelaar CF, "Interleukin-4 as a therapeutic target" Pharmacol. Ther. 2023; 242:108348. https://doi.org/10.1016/j.pharmthera.2023.108348
22. Egholm C, Heeb LEM, Impellizzieri D, Boyman O, "The Regulatory Effects of Interleukin-4 Receptor Signaling on Neutrophils in Type 2 Immune Responses" Front Immunol. 2019; 10:2507. https://doi.org/10.3389/fimmu.2019.02507
23.  Raza F, Babasyan S, Larson EM, Freer HS, Schnabel CL, Wagner B, "Peripheral blood basophils are the main source for early interleukin-4 secretion upon in vitro stimulation with Culicoides allergen in allergic horses" PLoS One. 2021; 16(5):e0252243.  https://doi.org/10.1371/journal.pone.0252243
24. Anovazzi G, Medeiros MC, Pigossi SC, Finoti LS, Souza Moreira TM, Mayer MP, Zanelli CF, Valentini SR, Rossa-Junior C, Scarel-Caminaga RM, "Functionality and opposite roles of two interleukin 4 haplotypes in immune cells" Genes Immun. 2017; 18(1):33-41. https://doi.org/10.1038/gene.2016.47
25. Junttila IS, "Tuning the Cytokine Responses: An Update on Interleukin (IL)-4 and IL-13 Receptor Complexes” Front Immunol. 2018; 9:888. https://doi.org/10.3389/fimmu.2018.00888
26. Sproston NR, Ashworth JJ, "Role of C-Reactive Protein at Sites of Inflammation and Infection” Front Immunol. 2018; 9:754. https://doi.org/10.3389/fimmu.2018.00754
27. Luan YY, Yao YM, "The Clinical Significance and Potential Role of C - reactive protein in Chronic Inflammatory and Neurodegenerative Diseases" Front Immunol. 2018; 9:1302. https://doi.org/10.3389/fimmu.2018.01302
28. Akinshipe BO, Yusuf EO, Ehiaghe AF, Egunjobi TO, Yusuf OA, “Elevated high-sensitivity C-reactive protein among apparently healthy adults with concomitant prediabetes and latent tuberculosis infection in Nigeria” Int J Res Med Sci. 2021; 9(2):338-46. https://doi.org/10.18203/2320-6012.ijrms20210407
29. Banait T, Wanjari A, Danade V, Banait S, Jain J, "Role of High-Sensitivity C-reactive Protein (Hs-CRP) in Non-communicable Diseases: A Review" Cureus. 2022; 14(10):e30225. https://doi.org/10.7759/cureus.30225
30. Patil VC, Avhad AB, Kulkarni AR, Pandere KA, "High-sensitive C-reactive protein in patients with coronary artery disease" J Nat Sc Biol Med. 2020; 11(1):39-44. https://doi.org/10.4103/jnsbm.JNSBM_159_19
31. Yadav S, Jangra R, Sharma BR, Sharma M, "Current Advancement in Biosensing techniques for determination of Alanine aminotransferase and Aspartate aminotransferase-a Mini Review" Process Biochem. 2022; 114:71-75. https://doi.org/10.1016/j.procbio.2022.01.010
32. Moriles KE, Azer SA, “Alanine Amino Transferase” In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022.
33. Chen ZW, Chen LY, Dai HL, Chen JH, Fang LZ, "Relationship between alanine aminotransferase levels and metabolic syndrome in nonalcoholic fatty liver disease" J Zhejiang Univ Sci B. 2008; 9(8):616-622. https://doi.org/10.1631/jzus.B0720016
34. Ihim AC, Habeeb Y, Manafa PO, Nwobodo EI, Edward UC, Obi PC, "Effect of Exposure to Soot on Activities of Alanine Transaminase, Gamma Glutamyl Transferase and Lipase among Cooks in Nnewi" JDDT, 2023;13(4):37-1. https://doi.org/10.22270/jddt.v13i4.5793
35. Gao N, Xu W, Ji J, Yang Y, Wang ST, Wang J, Chen X, Meng S, Tian X, Xu KF, "Lung function and systemic inflammation associated with short-term air pollution exposure in chronic obstructive pulmonary disease patients in Beijing, China" Environ Health. 2020; 19(1):12.  https://doi.org/10.1186/s12940-020-0568-1
36. Kalinauskaite-Zukauske V, Janulaityte I, Januskevicius A, Malakauskas K, "Serum levels of epithelial-derived mediators and interleukin-4/interleukin-13 signaling after bronchial challenge with Dermatophagoides pteronyssinus in patients with allergic asthma" Scand J Immunol. 2019; 90(5):e12820.  https://doi.org/10.1111/sji.12820
37. Alhamdow A, Lindh C, Albin M, Gustavsson P, Tinnerberg H, Broberg K, "Early markers of cardiovascular disease are associated with occupational exposure to polycyclic aromatic hydrocarbons" Sci Rep. 2017;7(1):9426. https://doi.org/10.1038/s41598-017-09956-x
38. Pilz V, Wolf K, Breitner S, Rückerl R, Koenig W, Rathmann W, Cyrys J, Peters A, Schneider A; KORA-Study group, "C-reactive protein (CRP) and long-term air pollution with a focus on ultrafine particles" Int J Hyg Environ Health. 2018; 221(3):510-518. https://doi.org/10.1016/j.ijheh.2018.01.016
39. Huang WH, Yen TH, Chan MJ, Su YJ, "Environmental carbon monoxide level is associated with the level of high-sensitivity C-reactive protein in peritoneal dialysis patients" Medicine (Baltimore). 2014; 93(26):e181. https://doi.org/10.1097/MD.0000000000000181
40. Elbarbary M, Oganesyan A, Honda T, Morgan G, Guo Y, Guo Y, Negin J, "Systemic Inflammation (C-Reactive Protein) in Older Chinese Adults Is Associated with Long-Term Exposure to Ambient Air Pollution" Int J Environ Res Public Health. 2021 Mar 22; 18(6):3258.  https://doi.org/10.3390/ijerph18063258
41. Ramdhan DH, Kurniasari F, Tejamaya M, Fitri A, Indriani A, Kusumawardhani A, Santoso M, "Increase of Cardiometabolic Biomarkers Among Vehicle Inspectors Exposed to PM0.25 and Compositions" Saf Health Work. 2021; 12(1):114-118. https://doi.org/10.1016/j.shaw.2020.08.005
42. Dey T, Gogoi K, Unni B, Bharadwaz M, Kalita M, Ozah D, Kalita M, Kalita J, Baruah PK, Bora T, "Role of environmental pollutants in liver physiology: special references to peoples living in the oil drilling sites of Assam" PLoS One. 2015; 10(4):e0123370. https://doi.org/10.1371/journal.pone.0123370
43. Zhang Z, Guo C, Chang LY, Bo Y, Lin C, Tam T, Hoek G, Wong MC, Chan TC, Lau AK, Lao XQ, "Long-term exposure to ambient fine particulate matter and liver enzymes in adults: a cross-sectional study in Taiwan" Occup Environ Med. 2019;76(7):488-494. https://doi.org/10.1136/oemed-2019-105695
44. Maglione GA, Kurtz ML, Orona NS, Astort F, Brites F, Morales C, Berra A, Tasat DR, "Changes in extrapulmonary organs and serum enzyme biomarkers after chronic exposure to Buenos Aires air pollution" Environ Sci Pollut Res Int. 2020;27(13):14529-14542.  https://doi.org/10.1007/s11356-020-07996-x
45. El-Tamawy MS, Zaki MA, Rashed LA, Esmail EH, Mohamed SS, Osama W, "Oligoclonal bands and levels of interleukin 4, interleukin 10, and tumor necrosis factor alpha in idiopathic intracranial hypertension Egyptian patients" Egypt J Neurol Psychiatry Neurosurg. 2019; 55:88.  https://doi.org/10.1186/s41983-019-0134-3
46. Ebrahimi M, Heidari-Bakavoli AR, Shoeibi S, Mirhafez SR, Moohebati M, Esmaily H, Ghazavi H, Saberi Karimian M, Parizadeh SM, Mohammadi M, Mohaddes Ardabili H, Ferns GA, Ghayour-Mobarhan M, "Association of Serum hs-CRP Levels With the Presence of Obesity, Diabetes Mellitus, and Other Cardiovascular Risk Factors" J Clin Lab Anal. 2016; 30(5):672-676.  https://doi.org/10.1002/jcla.21920