Could Bone Biomarkers Predict Bone Turnover after Kidney Transplantation?-A Proof-of-Concept Study.

AIM: Bone disease after kidney transplant (KT) results from multiple factors, including previous bone and mineral metabolism disturbances and effects of transplant-related medications. New biomolecules have been recently associated with the development and progression of the chronic kidney disease-associated bone and mineral disorder (CKD-MBD). These include sclerostin and the soluble receptor activator of nuclear factor-kB ligand (sRANKL). METHODS: To better understand the role of biomarkers in post-transplant bone disease, this study was designed to prospectively evaluate and correlate results from the histomorphometric analysis of bone biopsies after KT with emerging serum biomarkers of the CKD-MBD: sclerostin, Dickkopf-related protein 1 (Dkk-1), sRANKL and osteo-protegerin (OPG). RESULTS: Our data shows a significant increase in plasma levels of bioactive sclerostin after KT accompanied by a significant reduction in plasma levels of Dkk-1, suggesting a promotion of the inhibition of bone formation by osteoblasts through the activation of these inhibitors of the Wnt signaling pathway. In addition, we found a significant increase in plasma levels of free sRANKL after KT accompanied by a significant reduction in plasma levels of its decoy receptor OPG, suggesting an enhanced bone resorption by osteoclasts mediated by this mechanism. CONCLUSIONS: Taken together, these results suggest that the loss of bone volume observed after KT could be explain mainly by the inhibition of bone formation mediated by sclerostin accompanied by an enhanced bone resorption mediated by sRANKL.

C3 Glomerulonephritis Associated with Monoclonal Gammopathy of Renal Significance.

INTRODUCTION: Monoclonal gammopathy of renal significance (MGRS) is described as a hematologic condition characterized by nephrotoxicmonoclonal proteins produced by a non-malignant B-cell or plasma cell clone. Nevertheless, MGRS can cause serious renal lesions, leading to high morbidity. In C3 glomerulonephritis, a monoclonal protein can cause renal damage indirectly. Acting as an autoantibody, the protein cannot be detected in the kidney biopsy, promoting the dysregulation of the alternative pathway of the complement system. MATERIAL AND METHODS: This non-systematic review was based on a comprehensive search in databases and scientific journals, such as PubMed, Nature Reviews Nephrology and Kidney International, including the terms 'C3 Glomerulonephritis' and 'Monoclonal gammopathy of renal significance'. We review the pathophysiology, presentation, diagnosis, differential diagnosis and treatment of C3 glomerulonephritis associated with MGRS. DISCUSSION: With the increasing understanding of the complex interaction between monoclonal gammopathy and renal damage, such as C3 glomerulonephritis, it becomes clear that an early recognition is crucial, as Ig-directed therapy might improve outcomes. In this context, and in order to maximize the chance of a correct diagnosis, renal biopsy is mandatory to determine the exact nature of the lesion, and the severity of renal disease. Conclusion: It is important to make an early diagnosis of MGRS-associated C3 glomerulonephritis in order to prevent not only the progression to a hematological malignancy, but also end-stage renal disease.

Introdução: A gamopatia monoclonal de significado renal (MGRS) é descrita como uma doença hematológica caracterizada pela existência de proteínas monoclonais nefrotóxicas produzidas por um clone não maligno de células B ou plasmócitos. A MGRS pode causar lesões renais graves, levando a elevada morbilidade. Na glomerulonefrite C3, a proteína monoclonal pode causar indiretamente lesão renal. A proteína atua como auto-anticorpo, não sendo detetada na biópsia renal, promovendo a desregulação da via alternativa do complemento. Material e Métodos: Esta revisão não sistemática foi baseada numa pesquisa abrangente com recurso a base de dados e revistascientíficas, como a PubMed, Nature Reviews Nephrology e Kidney International, utilizando os termos 'Glomerulonefrite C3' e 'Gamopatia monoclonal de significado renal'. Apresentamos uma revisão da fisiopatologia, apresentação clínica, diagnóstico, diagnóstico diferencial e tratamento de glomerulonefrite C3 associado a MGRS Discussão: Com a crescente compreensão da complexa interação entre a gamopatia monoclonal e a lesão renal, como é exemplo a glomerulonefrite C3, torna-se claro que um reconhecimento precoce é crucial, dado que a terapia dirigida à Ig pode melhorar o resultado. Neste contexto, para maximizar a probabilidade de um diagnóstico correto, uma biópsia renal é necessária para determinar a natureza exata da lesão e a severidade da doença renal. Conclusão: É importante realizar um diagnóstico precoce de glomerulonefrite G3 associada a MGRS de modo a prevenir não apenas a progressão para uma neoplasia hematológica, mas também para doença renal terminal.

Evolution of bone disease after kidney transplantation: A prospective histomorphometric analysis of trabecular and cortical bone.

AIM: Post-transplant bone disease results from multiple factors, including previous bone and mineral metabolism disturbances and effects from transplant-related medications. Bone biopsy remains the gold-standard diagnostic tool. METHODS: We aimed to prospectively evaluate trabecular and cortical bone by histomorphometry after kidney transplantation. Seven patients, willing to perform follow-up bone biopsy, were included in the study. Dual-X-ray absorptiometry and trans-iliac bone biopsy were performed within the first 2 months after renal transplantation and repeated after 2-5 years of follow-up. RESULTS: Follow-up biopsy revealed a significant decrease in osteoblast surface/bone surface (0.91 ± 0.81 to 0.47 ± 0.12%, P = 0.036), osteoblasts number/bone surface (0.45 (0.23, 0.94) to 0.00/mm(2) , P = 0.018) and erosion surface/bone surface (3.75 ± 2.02 to 2.22 ± 1.38%, P = 0.044). A decrease in trabecular number (3.55 (1.81, 2.89) to 1.55/mm (1.24, 2.06), P = 0.018) and increase in trabecular separation (351.65 ± 135.04 to 541.79 ± 151.91 µm, P = 0.024) in follow-up biopsy suggest loss in bone quantity. We found no significant differences in cortical analysis, except a reduction in external cortical osteonal eroded surface (5.76 (2.94, 13.97) to 3.29% (0.00, 6.67), P = 0.043). Correlations between bone histomorphometric and dual-X-ray absorptiometry parameters gave inconsistent results. CONCLUSIONS: The results show a reduction in bone activity, suggesting increased risk of adynamic bone and loss of bone volume. Cortical bone seems less affected by post-transplant biological changes in the first years after kidney transplantation.

Lung and renal transplantation.

UNLABELLED: Renal transplantation is the most common type of solid organ transplantation and kidney transplant recipients are susceptible to pulmonary complications of immunosuppressive therapy, which are a diagnostic and therapeutic challenge. AIM: To evaluate patients admitted to the Renal Transplant Unit (RTU) of Hospital de S. João with respiratory disease. SUBJECT AND METHODS: We performed a retrospective study of all patients admitted to RTU with respiratory disease during a period of 12 months. RESULTS: Thirty-six patients were included. Mean age 55.2 (+/-13.4) years; 61.1% male. Immunosuppressive agents most frequently used were prednisolone and mycophenolate mofetil associated with ciclosporin (38.9%) or tacrolimus (22.2%) or rapamycin (13.9%). Thirty-one patients (86.1%) presented infectious respiratory disease. In this group the main diagnoses were 23 (74.2%) pneumonias, 5 (16.1%) opportunistic infections, 2 (6.5%) tracheobronchitis, and 1 case (3.2%) of lung abscesses. Microbiological agent was identified in 7 cases (22.6%). Five patients (13.9%) presented rapamycin-induced lung disease. Fibreoptic bronchoscopy was performed in 15 patients (41.7%), diagnostic in 10 cases (66.7%). Mean hospital stay was 17.1 (+/-18.5) days and no related death was observed. CONCLUSION: Respiratory infections were the main complications in these patients. Drug-induced lung disease implies recognition of its features and a rigorous monitoring of drug serum levels. A more invasive diagnostic approach was determinant in the choice of an early and more specific therapy.