Association of Dickkopf-1 Polymorphisms With Radiological Damage and Periodontal Disease in Patients With Early Rheumatoid Arthritis: A Cross-Sectional Study.

BACKGROUND: Rheumatoid arthritis (RA) is a systemic autoimmune disease that increased bone resorption. Periodontal disease (PD) is an associated risk factor of RA. Studies suggest an association between bone markers such as the dickkopf-related protein 1 (DKK-1) and progression of radiological damage. We aimed to evaluate the marker DKK-1, its polymorphisms in patients with early rheumatoid arthritis (eRA), and its association with rheumatic, radiological, and periodontal variables. METHODS: This is a cross-sectional study. Samples were obtained from 63 patients with eRA. Radiographs of hands and feet were evaluated by Sharp-van der Heijde score (SHS) and Simple Erosion Narrowing Score (SENS). Serum DKK-1 levels and high-resolution fusion analysis was used for polymorphisms (rs1896368, rs1896367, rs1528873). Bivariate analyses were performed. RESULTS: Individuals heterozygous for rs1896367 had more frequent erosions (p = 0.026) and joint space narrowing (p = 0.005) in the feet, higher SHS (p = 0.016), and higher SENS (p ≤ 0.001). Patients homozygous for rs1896368 had less frequent joint space narrowing in hands and feet as assessed by SHS and less presence of erosions by SENS (odds ratio, 0.04; 95% confidence interval, 0.00-0.93; p < 0.05). The presence of PD was associated with the homozygous of rs1896367 (p = 0.009) and the heterozygous of rs1896368 (p = 0.033). CONCLUSIONS: Polymorphism rs1896367 seems to be associated with greater radiological compromise; rs1896368 confers protection against bone damage in Colombian eRA patients.

Obtención de hidroxiapatita sintética por tres métodos diferentes y su caracterización para ser utilizada como sustituto óseo / Synthetic hydroxyapatite obtaining using three different methods and characterization to use it as bone substitute

El método de obtención de la hidroxiapatita (HAp) para ser utilizada como sustituto óseo, debe ofrecer un producto de alta pureza, rendimiento, rapidez y bajo costo, y contar con propiedades como bioactividad, biocompatibilidad, osteoconductividad y unión directa al hueso. En este trabajo se elaboró HAp sintética mediante tres métodos reportados en la literatura de vía sinterización y vía precipitación. El material obtenido se caracterizó por espectrometría de absorción atómica (AAS), espectrometría de absorción molecular (UV-Vis), espectroscopía infrarroja con transformada de Fourier (FTIR), difracción de rayos X (XRD), microscopía electrónica de barrido (SEM) y espectroscopía por dispersión de energía de rayos X (EDX). La ruta de síntesis de HAp por precipitación ofreció mejores resultados, comparados con la muestra estándar comercial y el hueso bovino, obteniéndose un tamaño de grano aproximado de 1 µm, relación molar Ca/P de 1,7, alta pureza y cristalinidad; mientras que los resultados obtenidos por vía sinterización mostraron la presencia de fases amorfas. El método de síntesis por precipitación vía húmeda usando nitratos de calcio y fosfatos, mostró ser práctico y adecuado para realizar la inmovilización de HAp sobre un soporte metálico como silicio, importante para su uso en cirugía reconstructiva en el área odontológica y médica.

The method by which to obtain Hydroxyapatite to be used as bone substitute should offer specific qualities such as, high purity, performance, low cost and has to be the following, bioactive, biocompatible, it has to have osteoconductivity and it has to bond directly to the bone. In this paper, synthetic HAp was prepared using 3 different methods reported in the literature as a route via sintering and precipitation, and subsequently characterized by atomic absorption spectrometry (AAS), molecular absorption spectrometry (UV-Vis), infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy X-ray (EDX). The route of synthesis of HAp precipitation gives better results, compared to the commercial standard sample and bovine bone, such as grain size which is of about 1 µm, molar ratio Ca/P of 1.7, high purity and crystallinity, while the results obtained via sintering show the presence of amorphous phases. The synthesis method using a wet precipitation of calcium nitrates and phosphates is practical and suitable for the immobilization of HAp on a metal substrate such as silicon, important for the use in dental and medical reconstructive surgery.