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Open Access Research article

Mitochondrial DNA (mtDNA) haplogroups and serum levels of anti-oxidant enzymes in patients with osteoarthritis

Mercedes Fernandez-Moreno1, Angel Soto-Hermida1, Sonia Pertega2, Natividad Oreiro1, Carlos Fernandez-Lopez1, Ignacio Rego-Perez1 and Francisco J Blanco13*

  • * Corresponding author: Francisco J Blanco fblagar@sergas.es

  • † Equal contributors

Author Affiliations

1 Osteoarticular and Aging Research Lab. Rheumatology Division. INIBIC-Hospital Universitario A Coruña. Spain

2 Epidemiology Unit, INIBIC-Hospital Universitario A Coruña. Spain

3 CIBER-BBN. ISCIII, Spain

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BMC Musculoskeletal Disorders 2011, 12:264  doi:10.1186/1471-2474-12-264

Published: 22 November 2011

Abstract

Background

Oxidative stress play a main role in the initiation and progression of the OA disease and leads to the degeneration of mitochondria. To prevent this, the chondrocytes possess a well-coordinated enzymatic antioxidant system. Besides, the mitochondrial DNA (mtDNA) haplogroups are associated with the OA disease. Thus, the main goal of this work is to assess the incidence of the mtDNA haplogroups on serum levels of two of the main antioxidant enzymes, Manganese Superoxide Dismutase (Mn-SOD or SOD2) and catalase, and to test the suitability of these two proteins for potential OA-related biomarkers.

Methods

We analyzed the serum levels of SOD2 and catalase in 73 OA patients and 77 healthy controls carrying the haplogroups J, U and H, by ELISA assay. Knee and hip radiographs were classified according to Kellgren and Lawrence (K/L) scoring from Grade 0 to Grade IV. Appropriate statistical analyses were performed to test the effects of clinical variables, including gender, body mass index (BMI), age, smoking status, diagnosis, haplogroups and radiologic K/L grade on serum levels of these enzymes.

Results

Serum levels of SOD2 appeared statistically increased in OA patients when compared with healthy controls (p < 0.001). Even in those OA patients with higher OA severity (K/L grade IV), the serum levels of this antioxidant enzyme appeared more significantly increased than in OA patients with lower K/L grade (p < 0.001). The mtDNA haplogroups showed an influence on serum levels of catalase (p = 0.054), being carriers of the mtDNA haplogroup J those who showed higher serum levels than non-J carriers (p = 0.057).

Conclusions

The increased levels of SOD2 in OA patients indicate an increased oxidative stress OA-related, therefore this antioxidant enzyme could be a suitable candidate biomarker for diagnosis of OA. Mitochondrial haplogroups significantly correlates with serum levels of catalase