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Dear Editor,
We read with great interest the article by Rumora and colleagues entitled “Paraoxonase 1 activity in patients with chronic obstructive pulmonary disease,” in which the investigators reported that patients with chronic obstructive pulmonary disease had significantly lower paraoxonase-1 (PON-1) activity compared to the healthy subjects (Citation1). However, we think that some points should be discussed.
PON-1 hydrolyzes organophosphate substrate paraoxon and aromatic esters, such as phenylacetate and has been shown to inhibit LDL oxidation. Previous studies showed that certain diseases such as psoriasis, chronic renal failure, inflammatory bowel diseases, hypertension, Parkinson's disease, Alzheimer disease, vascular dementia, chronic liver disease, systemic lupus erythematosus, hyperlipidemia and acute phase response status could affect serum PON-1 activity (Citation2, 3). However, the authors expressed several diseases such as infective and inflammatory diseases as exclusion criteria; it would be better if they applied simple laboratory tests such as routine biochemistry tests, complete blood count, thyroid function tests, erythrocyte sedimentation rate and C reactive protein to provide robust data about study groups.
Another contributing factor for PON-1 activity is medicine use. It is known that just lipid lowering drugs, aspirin, dexametazon, fenofibrate, phenobarbital, and hormone replacement therapy could affect PON-1 activity (Citation4). In addition, dietary supplements such as vitamin E, vitamin C, zinc, iron, and flavonoids can alter PON-1 activity (Citation5).
It is known that women have higher PON-1 activity than men. In this study, control and patient groups did not match in terms of gender. Therefore, the finding of the study as higher mean PON-1 activity in control group than patients may have arisen from this non-uniform distribution of participants. Namely, we think that it is essential to provide age- and sex-matched control group for this study.
In conclusion, although this study contributes valuable information to the medical literature, clarifying these concerns will certainly provide a clearer picture while interpreting PON-1 activity among participants.
Declaration of Interest Statement
The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References
- Rumora L, Rajkovic MG, Kopcinovic LM, Pancirov D, Cepelak I, Grubisic TZ. Paraoxonase 1 activity in patients with chronic obstructive pulmonary disease. COPD 2014; 11:539–545.
- Costa LG, Vitalone A, Cole TB, Furlong CE. Modulation of paraoxonase (PON1) activity. Biochem Pharmacol 2005; 69:541–550.
- Ferre N, Camps J, Prats E, Vilella E, Paul A, Figuera L, et al. Serum paraoxonase activity: a new additional test for the improved evaluation of chronic liver damage. Clin Chem 2002; 48:261–268.
- Mackness MI, Hallam SD, Peard T, Warner S, Walker CH. The separation of sheep and human serum “A”-esterase activity into the lipoprotein fraction by ultracentrifugation. Comp Biochem Physiol B 1985; 82:675–677.
- Rantala M, Silaste ML, Tuominen A, Kaikkonen J, Salonen JT, Alfthan G, et al. Dietary modifications and gene polymorphisms alter serum paraoxonase activity in healthy women. J Nutr 2002; 132:3012–3017.