ABSTRACT Objective To measure type 1 serum amino-terminal propeptide procollagen (P1NP) and type 1 cross-linked C-terminal telopeptide collagen (CTX) before parathyroidectomy (PTX) in PHPT patients, correlating these measurements with bone mineral density (BMD) changes. Subjects and methods 31 primary hyperparathyroidism (HPTP) were followed from diagnosis up to 12-18 months after surgery. Serum levels of calcium, parathyroid hormone (PTH) vitamin D, CTX, P1NP, and BMD were measured before and 1 year after surgery. Results One year after PTX, the mean BMD increased by 8.6%, 5.5%, 5.5%, and 2.2% in the lumbar spine, femoral neck (FN), total hip (TH), and distal third of the nondominant radius (R33%), respectively. There was a significant correlation between BMD change 1 year after the PTX and CTX (L1-L4: r = 0.614, p < 0.0003; FN: r = 0.497, p < 0.0051; TH: r = 0.595, p < 0.0005; R33%: r = 0.364, p < 0.043) and P1NP (L1-L4: r = 0,687, p < 0,0001; FN: r = 0,533, p < 0,0024; TH: r = 0,642, p < 0,0001; R33%: r = 0,467, p < 0,0079) preoperative levels. The increase in 25(OH)D levels has no correlation with BMD increase (r = -0.135; p = 0.4816). On linear regression, a minimum preoperative CTX value of 0.331 ng/mL or P1NP of 37.9 ng/mL was associated with a minimum 4% increase in L1-L4 BMD. In TH, minimum preoperative values of 0.684 ng/mL for CTX and 76.0 ng/mL for P1NP were associated with a ≥ 4% increase in BMD. Conclusion PHPT patients presented a significant correlation between preoperative levels of turnover markers and BMD improvement 1 year after PTX.

Resumo Introdução: O hiperparatireoidismo é uma complicação frequente da doença renal crônica (DRC). A paratireoidectomia (PTX) total com autotransplante (AT) de tecido paratireoideano é uma opção terapêutica para os indivíduos que não respondem ao manejo clínico. Objetivo: Avaliar a resposta do tecido paratireoideano enxertado durante hipocalcemia induzida em pacientes portadores de DRC submetidos à PTX total com AT. Métodos: Dezoito pacientes portadores de hiperparatiroidismo associado à DRC foram submetidos à PTX total com AT de tecido paratireoideano selecionado por estereomicroscopia entre Abril e Outubro de 2008 em nosso serviço. Onze indivíduos (oito com transplante renal funcionante, 2 em diálise peritoneal e 1 em hemodiálise) apresentavam boa condição clínica e foram elegíveis para o teste. Induziu-se hipocalcemia por infusão de bicarbonato de sódio em 5 controles normais e nos pacientes 6-12 meses após a PTX. Resultados: A hipocalcemia determinou um aumento importante dos níveis de PTH intacto (iPTH) no grupo controle 4 minutos após a infusão de bicarbonato. Nos pacientes, houve uma redução significativa do cálcio ionizado [de 1,17 ± 0,12 para 1,09 ± 0,11 (media ± EP) mmol/L] no 4º minuto (p < 0,001) ilustrando o nadir do teste. No 10º minuto não houve elevação do cálcio ionizado comparado ao 4º minuto (p = 0,451). Os níveis de iPTH foram de 34,8 ± 18,6 para 34,1 ± 18,8 pg/mL (valor basal semelhante ao 4º minuto p = 0,087) e se mantiveram no 10º minuto (33,3 ± 19,6 pg/mL p = 0,693). Conclusão: Em pacientes portadores de DRC testados 6-12 meses depois da cirurgia, o enxerto de tecido paratireoideano revelou incapacidade de resposta à hipocalcemia induzida por bicarbonato sem mudança dos níveis de iPTH.

Abstract Introduction: Hyperparathyroidism is a frequent complication of chronic kidney disease (CKD). Total parathyroidectomy (PTX) with parathyroid tissue autotransplantation (AT) is a treatment option in those individuals that do not respond to clinical management. Objective: To evaluate grafted parathyroid tissue response during induced hypocalcemia among CKD patients who underwent total PTX with AT. Methods: Eighteen patients with renal hyperparathyroidism were submitted to total PTX with parathyroid AT selected by stereomicroscopy between April and October 2008. Eleven (eight with successful kidney transplantation, 2 in peritoneal dialysis and 1 in hemodialysis) were clinically stable and eligible for testing. Hypocalcemia was induced using sodium bicarbonate infusion in 5 healthy controls and in patients 6-12 months after surgery. Results: Among controls, hypocalcemia elicited a major rise in intact PTH (iPTH) levels 4 minutes after bicarbonate infusion. In patients, a significant decrease in ionized calcium concentration was observed [from 1.17 ± 0.12 to 1.09 ± 0.11 mean (± SE) mmol/L] in the 4th minute (p < 0.001) illustrating the nadir point. In the 10thminute, ionized calcium did not show a statistical increase compared to the 4th minute (p = 0.451). The iPTH levels ranged from 34.8 ± 18.6 to 34.1 ± 18.8 pg/mL (similar values between base line and 4thminute p = 0.087) and did not change in the 10th minute (33.3 ± 19,6 pg/ mL p = 0.693). Conclusion: Among CKD patients tested 6-12 months after surgery, grafted parathyroid tissue revealed a blunted secretory capacity during bicarbonate induced hypocalcemia with no changes in iPTH levels