Measurement of serum paraoxonase activity and MDA concentrations in patients suffering with oral squamous cell carcinoma

Paraoxonase-1: How a xenobiotic detoxifying enzyme has become an actor in the pathophysiology of infectious diseases and cancer

Both infectious and non-infectious diseases can share common molecular mechanisms, including oxidative stress and inflammation. External factors, such as bacterial or viral infections, excessive calorie intake, inadequate nutrients, or environmental factors, can cause metabolic disorders, resulting in an imbalance between free radical production and natural antioxidant systems. These factors may lead to the production of free radicals that can oxidize lipids, proteins, and nucleic acids, causing metabolic alterations that influence the pathogenesis of the disease. The relationship between oxidation and inflammation is crucial, as they both contribute to the development of cellular pathology. Paraoxonase 1 (PON1) is a vital enzyme in regulating these processes. PON1 is an enzyme that is bound to high-density lipoproteins and protects the organism against oxidative stress and toxic substances. It breaks down lipid peroxides in lipoproteins and cells, enhances the protection of high-density lipoproteins against different infectious agents, and is a critical component of the innate immune system. Impaired PON1 function can affect cellular homeostasis pathways and cause metabolically driven chronic inflammatory states. Therefore, understanding these relationships can help to improve treatments and identify new therapeutic targets. This review also examines the advantages and disadvantages of measuring serum PON1 levels in clinical settings, providing insight into the potential clinical use of this enzyme.

Abnormal expression of HADH, an enzyme of fatty acid oxidation, affects tumor development and prognosis (Review)

Tumor occurrence and progression are closely associated with abnormal energy metabolism and energy metabolism associated with glucose, proteins and lipids. The reprogramming of energy metabolism is one of the hallmarks of cancer. As a form of energy metabolism, fatty acid metabolism includes fatty acid uptake, de novo synthesis and β‑oxidation. In recent years, the role of abnormal fatty acid β‑oxidation in tumors has gradually been recognized. Mitochondrial trifunctional protein (MTP) serves an important role in fatty acid β‑oxidation and HADH (two subtypes: α subunit, HADHA and β subunit, HADHB) are important subunits of MTP. HADH participates in the steps of 2, 3 and 4 fatty acid β‑oxidation. However, there is no review summarizing the specific role of HADH in tumors. Therefore, the present study focused on HADH as the main indicator to explore the changes in fatty acid β‑oxidation in several types of tumors. The present review summarized the changes in HADH in 11 organs (cerebrum, oral cavity, esophagus, liver, pancreas, stomach, colorectum, lymph, lung, breast, kidney), the effect of up‑ and downregulation and the relationship of HADH with prognosis. In summary, HADH can be either a suppressor or a promoter depending on where the tumor is located, which is closely associated with prognostic assessment. HADHA and HADHB have similar prognostic roles in known and comparable tumors.

The 'Danse Macabre'-Neutrophils the Interactive Partner Affecting Oral Cancer Outcomes

Over the past few decades, tremendous advances in the prevention, diagnosis, and treatment of cancer have taken place. However for head and neck cancers, including oral cancer, the overall survival rate is below 50% and they remain the seventh most common malignancy worldwide. These cancers are, commonly, aggressive, genetically complex, and difficult to treat and the delay, which often occurs between early recognition of symptoms and diagnosis, and the start of treatment of these cancers, is associated with poor prognosis. Cancer development and progression occurs in concert with alterations in the surrounding stroma, with the immune system being an essential element in this process. Despite neutrophils having major roles in the pathology of many diseases, they were thought to have little impact on cancer development and progression. Recent studies are now challenging this notion and placing neutrophils as central interactive players with other immune and tumor cells in affecting cancer pathology. This review focuses on how neutrophils and their sub-phenotypes, N1, N2, and myeloid-derived suppressor cells, both directly and indirectly affect the anti-tumor and pro-tumor immune responses. Emphasis is placed on what is currently known about the interaction of neutrophils with myeloid innate immune cells (such as dendritic cells and macrophages), innate lymphoid cells, natural killer cells, and fibroblasts to affect the tumor microenvironment and progression of oral cancer. A better understanding of this dialog will allow for improved therapeutics that concurrently target several components of the tumor microenvironment, increasing the possibility of constructive and positive outcomes for oral cancer patients. For this review, PubMed, Web of Science, and Google Scholar were searched for manuscripts using keywords and combinations thereof of "oral cancer, OSCC, neutrophils, TANs, MDSC, immune cells, head and neck cancer, and tumor microenvironment" with a focus on publications from 2018 to 2021.

Association of Plasma Carotenoid and Malondialdehyde Levels with Physical Performance in Korean Adolescents

Increased oxidative stress has been shown to lead to muscle damage and reduced physical performance. The antioxidant mechanism is most likely to reduce these relationships, but in the context of the action of carotenoids, more research is needed. This study aimed to investigate whether carotenoids modify the association between plasma malondialdehyde (MDA) and physical performance in Korean adolescents. The study sample consisted of 381 adolescents (164 boys, 217 girls) aged 13–18, who participated in the 2018 National Fitness Award Project. We quantified α-carotene, β-carotene, β-cryptoxanthin, lutein, zeaxanthin, lycopene, and MDA levels in plasma using HPLC with photodiode array detection. Among boys but not girls, plasma MDA level was negatively associated (β = −0.279, p = 0.0030) with total plasma carotenoid levels and marginally negatively associated (β = −0.907, p = 0.0876) with absolute hand grip strength. After adjustment for covariates in boys, the MDA level was negatively associated with absolute hand grip strength and relative hand grip strength; this association was observed only in groups with individual carotenoid and total carotenoid values below the median. These findings support a significant association between plasma MDA level and hand grip strength, and this association has been potentially modified by plasma levels of carotenoids in Korean male adolescents.

Parameters of Oxidative Stress, Vitamin D, Osteopontin, and Melatonin in Patients with Lip, Oral Cavity, and Pharyngeal Cancer

Lip, oral cavity, and pharyngeal cancers (LOCP) constitute a group of rare neoplasms with unfavorable prognosis. So far, not much is known about the role of vitamin D and oxidative stress in the pathogenesis of LOCP in the European population. The aim of the study was to determine the concentrations of vitamin D, osteopontin, melatonin, and malondialdehyde (MDA) as markers of oxidative stress and/or inflammation, as well as the activities of antioxidant enzymes in the course of LOCP. The vitamin D, melatonin, and osteopontin concentrations in blood serum, the MDA levels in erythrocytes and blood plasma, and the activities of superoxide dismutase (SOD-1), catalase (CAT), and glutathione peroxidase (GPx) in erythrocytes were measured in blood samples taken from 25 LOCP patients of middle age (YCG), 20 LOCP elderly patients (OCG), and 25 healthy middle-aged volunteers. In both cancer groups, decreases in vitamin D and CAT, as well as increases in osteopontin and blood plasma MDA, were observed. An increase in GPx activity in YCG and a decrease in melatonin level in OCG were found. The results indicate the vitamin D deficiency and disturbed oxidant-antioxidant homeostasis in LOCP patients. Osteopontin seems to be associated with LOCP carcinogenesis and requires further research.

Malondialdehyde, an Oxidative Stress Marker in Oral Squamous Cell Carcinoma-A Systematic Review and Meta-Analysis

Objective: To qualitative and quantitatively review published literature assessing the oxidative stress marker malondialdehyde (MDA) in oral squamous cell carcinoma (OSCC). Methodology: Pubmed (MeSH), Science Direct, Scopus, Web of Science, Willey Online Library, Cochrane, and Cross Reference were searched for studies assessing MDA levels in OSCC samples. Results: From the 1008 articles identified, 849 were excluded based on title and abstract screening due to duplication and irrelevance to the topic of interest. Full-text assessment of the remaining 159 articles led to the inclusion of only 46 articles that satisfied the selection criteria. Of these, only 26 studies had data compatible for quantitative analysis. The MDA levels in OSCC groups are significantly increased (p < 0.00001) in plasma, serum, and saliva samples in the majority of the studies evaluated. In contrast, MDA levels in OSCC tissue samples are significantly attenuated (p < 0.00001) compared to healthy controls, supported by fewer studies. Conclusions: The augmented MDA levels in plasma, serum, and saliva samples of the OSCC reflect the heightened oxidative stress level accurately. Further studies are required to understand the attenuated MDA levels in the tissue samples of OSCC. Correlation analysis between MDA levels with established clinicopathological prognostic markers could aid in formulating oxidative stress-based prognostication and treatment planning.

The Fatty Acid and Protein Profiles of Circulating CD81-Positive Small Extracellular Vesicles Are Associated with Disease Stage in Melanoma Patients

Simple Summary

Early detection of cutaneous melanoma is the key to increasing survival and proper therapeutic adjustment, especially in stages II–IV. We investigated whether the fatty acid (FA) and protein compositions of small extracellular vesicles (sEV) expressing CD81, derived from the plasma of stage 0–I, II and III–IV melanoma patients, could reflect disease stage. Results showed a higher content of FA and differences in C18:0/C18:1 ratio, a marker of cell membrane fluidity, that distinguished patients’ CD81sEV from those of healthy donors (HD). By proteomic analysis (identifier PXD024434) we identified significant increases in CD14, PON1, PON3 and APOA5 in stage II CD81sEV compared to HD. In stage III–IV, CD81sEV’ RAP1B expression was decreased. These stage-related signatures may support the potential of sEV to provide information for early diagnosis, prediction of metastatic behavior, treatment and follow-up of melanoma patients.

Abstract

The early detection of cutaneous melanoma, a potentially lethal cancer with rising incidence, is fundamental to increasing survival and therapeutic adjustment. In stages II–IV especially, additional indications for adjuvant therapy purposes after resection and for treatment of metastatic patients are urgently needed. We investigated whether the fatty acid (FA) and protein compositions of small extracellular vesicles (sEV) derived from the plasma of stage 0–I, II and III–IV melanoma patients (n = 38) could reflect disease stage. The subpopulation of sEV expressing CD81 EV marker (CD81sEV) was captured by an ad hoc immune affinity technique from plasma depleted of large EV. Biological macromolecules were investigated by gas chromatography and mass spectrometry in CD81sEV. A higher content of FA was detectable in patients with respect to healthy donors (HD). Moreover, a higher C18:0/C18:1 ratio, as a marker of cell membrane fluidity, distinguished early (stage 0–I) from late (III–IV) stages’ CD81sEV. Proteomics detected increases in CD14, PON1, PON3 and APOA5 exclusively in stage II CD81sEV, and RAP1B was decreased in stage III–IV CD81sEV, in comparison to HD. Our results suggest that stage dependent alterations in CD81sEV’ FA and protein composition may occur early after disease onset, strengthening the potential of circulating sEV as a source of discriminatory information for early diagnosis, prediction of metastatic behavior and following up of melanoma patients.

Association of PON1, TNF-α and TGF-β gene polymorphisms with prognosis in oral and oropharyngeal squamous cell carcinoma

OBJECTIVE

The oral and oropharyngeal squamous cell carcinoma (OOSCC) accounts for 90-95% of tumours in the oral cavity. Single nucleotide polymorphism (SNP) in the coding region of PON1, tumour necrosis factor-alpha (TNF-α) and transforming growth factor-beta (TGF-β) have been associated with to development of different cancers. Our aim was to investigate the prognostic value of PON1 (rs854560 and rs662), TNF-α (rs1800629 and rs361525) and TGF-β (rs1800469) SNPs in OOSCC.

MATERIALS AND METHODS

We genotyped 163 OOSCC patients and 146 patients from group of control for PON1 (rs854560 and rs662), TNF-α (rs1800629 and rs361525) and TGF-β (rs1800469) SNPs by real-time polymerase chain reaction (PCR).

RESULTS

TNF-α (rs1800629) GG genotype was significantly more frequent in intraoral lesions and clinical stages III and IV, while the polymorphic AA genotype in lip lesion and clinical stages I and II. Moreover, TGF-β (rs1800469) AG and AA genotypes were significantly more frequent in larger tumours (T3 e T4). TNF-α (rs1800629) AG genotype had poor survival and patients carrying the PON1 (rs662) TT genotype tended to poor survival.

CONCLUSIONS

Results suggest that the rs1800629 and rs1800469 could exert influence in the more aggressive behaviour of OOSCC and the genotypes AG of rs1800629, and TT of rs662 could be markers with prognostic value in OOSCC.

On the Role of Paraoxonase-1 and Chemokine Ligand 2 (C-C motif) in Metabolic Alterations Linked to Inflammation and Disease. A 2021 Update

Infectious and many non-infectious diseases share common molecular mechanisms. Among them, oxidative stress and the subsequent inflammatory reaction are of particular note. Metabolic disorders induced by external agents, be they bacterial or viral pathogens, excessive calorie intake, poor-quality nutrients, or environmental factors produce an imbalance between the production of free radicals and endogenous antioxidant systems; the consequence being the oxidation of lipids, proteins, and nucleic acids. Oxidation and inflammation are closely related, and whether oxidative stress and inflammation represent the causes or consequences of cellular pathology, both produce metabolic alterations that influence the pathogenesis of the disease. In this review, we highlight two key molecules in the regulation of these processes: Paraoxonase-1 (PON1) and chemokine (C-C motif) ligand 2 (CCL2). PON1 is an enzyme bound to high-density lipoproteins. It breaks down lipid peroxides in lipoproteins and cells, participates in the protection conferred by HDL against different infectious agents, and is considered part of the innate immune system. With PON1 deficiency, CCL2 production increases, inducing migration and infiltration of immune cells in target tissues and disturbing normal metabolic function. This disruption involves pathways controlling cellular homeostasis as well as metabolically-driven chronic inflammatory states. Hence, an understanding of these relationships would help improve treatments and, as well, identify new therapeutic targets.

Changes in oxidation-antioxidation function on the thymus of chickens infected with reticuloendotheliosis virus

Background

Reticuloendotheliosis virus (REV) is a retrovirus that causes severe immunosuppression in poultry. Animals grow slowly under conditions of oxidative stress. In addition, long-term oxidative stress can impair immune function, as well as accelerate aging and death. This study aimed to elucidate the pathogenesis of REV from the perspective of changes in oxidative-antioxidative function following REV infection.

Methods

A total of 80 one-day-old specific pathogen free (SPF) chickens were randomly divided into a control group (Group C) and an REV-infected group (Group I). The chickens in Group I received intraperitoneal injections of REV with 10^4.62/0.1 mL TCID₅₀. Thymus was collected on day 1, 3, 7, 14, 21, 28, 35, and 49 for histopathology and assessed the status of oxidative stress.

Results

In chickens infected with REV, the levels of H₂O₂ and MDA in the thymus increased, the levels of TAC, SOD, CAT, and GPx1 decreased, and there was a reduction in CAT and Gpx1 mRNA expression compared with the control group. The thymus index was also significantly reduced. Morphological analysis showed that REV infection caused an increase in the thymic reticular endothelial cells, inflammatory cell infiltration, mitochondrial swelling, and nuclear damage.

Conclusions

These results indicate that an increase in oxidative stress enhanced lipid peroxidation, markedly decreased antioxidant function, caused thymus atrophy, and immunosuppression in REV-infected chickens.

Strenuous occupational physical activity: Potential association with esophageal squamous cell carcinoma risk

Objective:

The impact of recreational physical activity (RPA) on cancer risk has been extensively studied. However, the association of occupational physical activity (OPA), which differs in dose and intensity from RPA, with different cancers including esophageal squamous cell carcinoma (ESCC), has received less attention.

Materials and methods:

We conducted a hospital-based case–control study in Kashmir, India, majorly a rural population, to evaluate the association of OPA with ESCC risk. Histopathologically confirmed 703 ESCC cases and 1664 controls, individually matched to the respective cases for age, sex and district of residence, were recruited.

Main outcome measures:

Information on type, duration and intensity of physical activity was obtained in face-to-face interviews with participants using a structured questionnaire. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). Body mass index was unable to be accounted for in the analysis.

Results:

A high level of OPA was associated with increased ESCC risk (OR = 2.17, 95% CI; 1.41–3.32), compared to subjects with moderate OPA. The association with ESCC risk was stronger in strenuous workers (OR = 3.64, 95% CI; 2.13–6.20). The association of strenuous OPA with ESCC risk persisted only in subjects that were involved in strenuous activities for equal to or greater than five days/week.

Conclusions:

Our study suggests a possible association of strenuous OPA with ESCC risk. Although our results were adjusted for multiple factors, including indicators of socioeconomic status, more replicative occupational epidemiological studies are needed to rule out any residual confounding.

Characterization and antioxidant activity of the oligo-maltose fraction from Polygonum Cillinerve

In this study, Polygonum Cillinerve polysaccharide (PCP) was extracted, and characterized by high performance gel permeation chromatography, high performance liquid chromatography, fourier transform infrared spectroscopy, nuclear magnetic resonance and mass spectroscopy. The results showed that PCP was composed of glucose, it was α-D-glucan and the backbone of PCP was consisted of repeating units of (1→4)-α-D-Glucose. In addition, the antioxidant potential of PCP was assessed in vitro. The results showed that PCP had strong hydroxyl radical scavenging ability, some DPPH scavenging ability and good reducing power. Moreover, the results of the enzyme-linked immunosorbent assays showed that PCP at 15.625-0.975 μg/mL could significantly improve the level of superoxide dismutase and glutathione peroxidase, and could significantly decrease the level of myeloperoxidase, malondialdehyde and xanthine oxidase in macrophages. These results indicated that PCP could potentially be developed as a natural antioxidant.

Do CO2 and oxidative stress induce cancer?: a brief study about the evaluation of PON 1, CAT, CA and XO enzyme levels on head and neck cancer patients

Head and neck cancer (HNC) is one of the most common malignancies in the world. HNC is a group of cancers that starts in the mouth, nose, throat, larynx, sinuses, or salivary glands. According to this section of the body parts; induction of cancer can be associated with CO₂ and oxidative stress. The aim of this study is to assess the activities of carbonic anhydrase (CA), catalase (CAT), paraoxonase1 (PON1), and xanthine oxidase (XO) activities in 89 HNC patients and 115 healthy volunteers. Paraoxonase1 activity was found lower in HNC cancer patients. There is no statistically significant difference between patients and controls for catalase, carbonic anhydrase, and xanthine oxidase enzyme levels. According to this results, paraoxonase1 levels could be a candidate as an oxidative marker in HNC patients, but further studies are needed to investigate the other type of cancer related PON1 and the other enzyme levels.

Paraoxonase-1 activity in patients with cancer: A systematic review and meta-analysis

PURPOSE

Paraoxonase-1 (PON1) is a lipolactonase implicated in the elimination of carcinogenic free radicals and in the scavenging mechanisms to maintain oxidative balance. The objective of the present systematic review and meta-analysis was to evaluate possible alterations in serum PON1 activity in patients with cancer.

METHODS

A systematic search of the observational studies in humans published in the last 15 years was performed through Medline databases following the PRISMA and STARLITE statements. Further, a keyword-based computerized search with restrictions on publication date, and a meta-analysis of case-control studies was performed.

RESULTS

In total, 23 studies were included most of which reported decreased PON1 activity in patients with cancer. This could indicate impaired defense ability against oxidative stress with potential implications in cell proliferation, promotion of genetic instability, and alterations in cellular sensitivity to chemotherapy.

CONCLUSION

This systematic review and meta-analysis confirms a consistent association between cancer and decreased serum PON1 activities. These findings may open fruitful lines of research with clinical relevance, and an understanding of molecular alterations underlying carcinogenesis.

Effect of radiotherapy on activity and concentration of serum paraoxonase-1 in breast cancer patients

Paraoxonase-1 (PON1) is an intra-cellular antioxidant enzyme found also in the circulation associated with high-density lipoproteins. The activity of this enzyme has been shown to be decreased in breast cancer (BC) patients. The aims of our study were to investigate the changes produced by radiotherapy (RT) on activity and concentration of serum PON1 in BC patients, and to evaluate the observed variations in relation to clinical and pathological characteristics of patients and tumors, and the response to treatment. We studied 200 women with BC who were scheduled to receive RT following excision of the tumor. Blood for analyses was obtained before and after the irradiation procedure. The control group was composed of 200 healthy women. Relative to control, BC patients had significantly lower serum PON1 activities pre-RT, while PON1 concentrations were at similar levels. RT was associated with a significant increase in serum PON1 activities and concentrations. We observed significant differences in serum PON1 concentrations post-RT between patients with luminal A or luminal B tumors. Serum PON1 concentration post-RT was markedly lower in BC patients with metastases. We conclude that benefit from RT accrues to the BC patients not only through its direct effect on cancer cells but also indirectly by improving the organism’s anti-oxidant defense mechanisms. In addition, our preliminary evidence suggests that the measurement of serum PON1 concentration post-RT could be an efficient prognostic biomarker, and may be used as an index of the efficacy of the RT.

The role of paraoxonase in cancer

The paraoxonase (PON) gene family includes three proteins, PON1, PON2 and PON3. PON1 and PON3 are both associated with high-density lipoprotein (HDL) particles and exert anti-oxidant and anti-inflammatory properties. PON2 and PON3 are intracellular enzymes which modulate mitochondrial superoxide anion production and endoplasmic reticulum (ER) stress-induced apoptosis. The pleiotropic roles exerted by PONs have been mainly investigated in cardiovascular and neurodegenerative diseases. In recent years, overexpression of PON2 and PON3 has been observed in cancer cells and it has been proposed that both enzymes could be involved in tumor survival and stress resistance. Moreover, a lower activity of serum PON1 has been reported in cancer patients. This review summarizes literature data on the role of PONs in human cancers and their potential role as a target for antitumor drugs.

Oxidative Stress in Oral Diseases: Understanding Its Relation with Other Systemic Diseases

Oxidative stress occurs in diabetes, various cancers, liver diseases, stroke, rheumatoid arthritis, chronic inflammation, and other degenerative diseases related to the nervous system. The free radicals have deleterious effect on various organs of the body. This is due to lipid peroxidation and irreversible protein modification that leads to cellular apoptosis or programmed cell death. During recent years, there is a rise in the oral diseases related to oxidative stress. Oxidative stress in oral disease is related to other systemic diseases in the body such as periodontitis, cardiovascular, pancreatic, gastric, and liver diseases. In the present review, we discuss the various pathways that mediate oxidative cellular damage. Numerous pathways mediate oxidative cellular damage and these include caspase pathway, PERK/NRF2 pathway, NADPH oxidase 4 pathways and JNK/mitogen-activated protein (MAP) kinase pathway. We also discuss the role of inflammatory markers, lipid peroxidation, and role of oxygen species linked to oxidative stress. Knowledge of different pathways, role of inflammatory markers, and importance of low-density lipoprotein, fibrinogen, creatinine, nitric oxide, nitrates, and highly sensitive C-reactive proteins may be helpful in understanding the pathogenesis and plan better treatment for oral diseases which involve oxidative stress.

Fluoride-induced oxidative stress is involved in the morphological damage and dysfunction of liver in female mice

Fluoride (F), one of the most toxic environmental and industrial pollutants, is known to exert hepatotoxicity. The contribution of oxidative stress to the F tolerance of liver remains largely unknown. In this study, the morphological and ultrastructural characteristics of liver were observed using hematoxylin and eosin staining and transmission electron microscopy (TEM), respectively. Oxidative-stress participations was analysed and the mRNA expression levels of catalase (Cat), glutathione peroxidase 1 (GSH-Px1), nitric oxide synthase 2 (NOS2), and superoxide dismutase 1 (SOD1) were investigated by real-time PCR. Changes in liver-function parameters were also detected. Results showed that the reactive content of reactive oxygen species increased significantly, whereas SOD and GSH-Px activities, as well as total anti-oxidising capability (T-AOC), decreased significantly, with increased nitric oxide (NO) and malondialdehyde (MDA) contents in liver and serum after 70days of F treatment. The mRNA expression levels of Cat, GSH-Px1, and SOD were significantly downregulated, whereas NOS2 mRNA expression level was up upregulated, after F treatment for 70days. Light microscopy also revealed that hepatocytes were fused into pieces; cell boundaries were unclear, and nuclei were lightly stained. TEM further showed that hepatocytes were characterised by vague nuclear and mitochondrial membranes, dilated endoplasmic reticulum, and aggravated vacuolar degeneration. Activities of alanine transaminase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase, as well as the level of total bilirubin in serum increased. Overall, these results indicated that F interfered with the balance of antioxidase activity and morphological changes in liver, which were involved in mouse liver dysfunction.

[Is paraoxonase 1 a marker of cardiovascular risk in youth with type 1 diabetes? (Study about 109 cases)]

OBJECTIVES

We purpose to verify if paraoxonase 1 (PON1) activity may be a marker of cardiovascular risk in a young Tunisian population with type 1 diabetes (T1D).

METHODS

PON1 activity was measured by a kinetic method using paraoxon as substrate. The other parameters were determined by automated methods.

RESULTS

One hundred and nine children and adolescents with T1D and 97 healthy subjects were involved in this study. PON1 activity and PON1/HDL-cholesterol ratio were significantly decreased in diabetics (303 ± 174 vs. 372 ± 180 U/L and 221 ± 139 vs. 298 ± 20 1U/mmol, P=0.006, P=0.002, respectively) compared to controls. A significant increase in total cholesterol, LDL-c and microalbuminuria was observed in diabetics compared to controls. PON1 activity was decreased by 9.5% in patients with diabetes duration ≥ 6 years, by 28.4% for those with fasting glycemia ≥ 7 mmol/L (P<0.001), by 14% in those with HbA1c ≥ 8% and by 12.3% for diabetics with dyslipidemia. PON1 activity is reduced when the number of cardiovascular risk factors increases (P<0.001).

CONCLUSION

PON1 seems to be associated to cardiovascular risk markers in T1D. This result remains to be seen. Nevertheless, improving PON1 activity could be a significant target for reducing cardiovascular risk.

Serum paraoxonase-1 enzyme activities and oxidative stress levels in patients with esophageal squamous cell carcinoma

OBJECTIVES

Oxidative stress is well recognized to play a role in the pathogenesis of many diseases, including cancers. Paraoxonase-1 (PON1) is implicated in the elimination of carcinogenic lipid-soluble radicals produced by lipid peroxidation. Reports on PON1 activities in patients with cancer are conflicting. The aim of this study was to investigate serum antioxidant enzyme activities and oxidative stress levels in patients with esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

Thirty-two patients with ESCC and 33 healthy controls were enrolled. Serum malondialdehyde (MDA) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GR), paraoxonase, and arylesterase activities were measured spectrophotometrically.

RESULTS

Serum paraoxonase, arylesterase, SOD, activities, GSH-Px, and GR activities were significantly lower in patients with ESCC than in controls (all, P < 0.05), whereas serum MDA levels were significantly higher (P < 0.05). Serum MDA levels were significantly correlated with paraoxonase (r = -0.572, P < 0.001) and arylesterase activities (r = -0.597, P < 0.001) in patients with ESCC.

CONCLUSIONS

This study indicated that ESCC is associated with increased oxidative stress and decreased antioxidant enzyme activities. Decreased serum PON1 enzyme activities may play a role in the progression and/or development of ESCC. Further studies are required to clarify these results.