RESUMEN
Introducción: La densitometría ósea (DO) tiene alta especificidad para el diagnóstico de osteoporosis, pero sensibilidad bajo lo óptimo para estimar el riesgo de fracturas. Éste, se puede calcular por algoritmos de predictores, y se ha propuesto incluir los marcadores óseos (MO), pero la magnitud de su asociación es incierta. El MO recomendado para medir resorción ósea es Beta-Cross Laps (B-CTx), y uno de formación ósea es la osteocalcina. Objetivos: 1) Establecer rangos de B-CTx y N-MID osteocalcina (N-MID) en mujeres posmenopáusicas (MPM), y comparar los niveles entre grupos: 1) Control sano y 2) Con DO alterada. Material y Métodos: Se reclutaron MPM, con DO del último año. Se realizó encuesta de factores de riesgo de fracturas y medición de MO. Se excluyeron MPM con causa secundaria para compromiso del recambio óseo. Resultados: 117 MPM (57 control, 60 DO alterada), 18 % osteoporosis, comparables. Los rangos de B-CTx y N-MID fueron 0,41 ± 0,18 [IC95% 0,37- 0,45] y 22,76 ± 7,73 [IC95% 21,29-24,24] ng/mL. Los niveles promedios de B-CTx y N-MID fueron más altos en grupo con DO alterada (0,46 ± 0,19 y 24,29 ± 8,04 ng/mL). Se encontró correlación moderada entre ambos MO, pero débil con DO alterada. Conclusiones: Se determinaron por primera vez rangos de B-CTx y N-MID en MPM chilenas, corroborando la similitud a otros países. Se encontraron valores discretamente más elevados de MO en grupo DO alterada, probablemente atribuible a causas secundarias no reportadas. Estos MO podrían constituir una herramienta complementaria a la DO y FRAX en la evaluación ósea.
Introduction: Bone densitometry (BD) has high specificity in the osteoporosis diagnosis but suboptimal sensitivity to estimate fracture risk. It was proposed that bone turnover markers (BTM) could be included in the osteoporosis risk algorithm, although the extent of its association is unknown. One recommended BTM to assess bone resorption is Beta-Cross Laps (B-CTx), while a BTM to assess bone formation is osteocalcin. Aims: To establish BCTx and N-MID osteocalcin (N-MID) ranges in postmenopausal women (PM) and compare BTM levels in two groups: control and with abnormal BD. Methods: PM with BD within the last year were recruited. A questionnaire of risk factors for fractures was applied, and BTM was measured. Volunteers with diseases that would affect bone remodeling were excluded. Results: 117 PM (57 control and 60 with abnormal BD) were recruited. 18% had osteoporosis, and the groups were comparable. The ranges for B-CTx and N-MID were 0.41 ± 0.18 [IC95% 0.37-0.45] and 22.76 ± 7.73 [IC95% 21.29-24.24] ng/mL. The mean levels of B-CTx and N-MID were higher in the group with abnormal BD (0.46 ± 0.19 and 24.29 ± 8.04 ng/mL). A moderate correlation between both BTM was found, but it was weak with abnormal BD. Conclusions: B-CTx and N-MID ranges were assessed for the first time in Chilean PM, similar to values found in other countries. Slightly higher values of BTM were found in the group with abnormal BD, which the presence of omitted secondary causes could explain. These BTM could be a complementary tool to BD and FRAX in bone evaluation.
RESUMEN
BACKGROUND: The discovery of the phospholipase A2 receptor antigen and its highly specific autoantibody (anti-PLA2R Ab) was useful for the diagnosis and follow-up of patients with membranous nephropathy (MN). Thus, some international guidelines recommend not performing renal biopsy in patients with positive serum anti-PLA2R Ab. Aim: To evaluate the prevalence of anti-PLA2R Ab in serum and renal tissue samples from Chilean patients with primary MN. MATERIAL AND METHODS: Twenty-eight patients aged 50 ± 14 years (20 males) with biopsy-proven primary MN plus a negative workup for secondary causes were included. Measurements of serum and renal histologic anti-PLA2R Ab were performed. The relationship between the findings of serum and tissue anti-PLA2R Ab was evaluated. RESULTS: Fifteen patients (54 %) had anti-PLA2R Ab presence in serum and 19 patients (68%) had positive anti-PLA2R Ab in the renal biopsy. All patients with positive serum anti-PLA2R Ab had positive antibodies on immunohistochemistry. Conclusions: Serum anti-PLA2R Ab is potentially useful in the diagnosis of patients with suspected primary MN in Chilean population.