Updating the role of matrix metalloproteinases in mineralized tissue and related diseases

Abstract Bone development and healing processes involve a complex cascade of biological events requiring well-orchestrated synergism with bone cells, growth factors, and other trophic signaling molecules and cellular structures. Beyond health processes, MMPs play several key roles in the installation of heart and blood vessel related diseases and cancer, ranging from accelerating metastatic cells to ectopic vascular mineralization by smooth muscle cells in complementary manner. The tissue inhibitors of MMPs (TIMPs) have an important role in controlling proteolysis. Paired with the post-transcriptional efficiency of specific miRNAs, they modulate MMP performance. If druggable, these molecules are suggested to be a platform for development of "smart" medications and further clinical trials. Thus, considering the pleiotropic effect of MMPs on mammals, the purpose of this review is to update the role of those multifaceted proteases in mineralized tissues in health, such as bone, and pathophysiological disorders, such as ectopic vascular calcification and cancer.

Doxiciclina em pacientes com linfangioleiomiomatose: biomarcadores e resposta funcional pulmonar / Doxycycline use in patients with lymphangioleiomyomatosis: biomarkers and pulmonary function response

OBJETIVO: Avaliar o bloqueio da metaloproteinase da matriz (MMP)-2 e da MMP-9 e a variação do VEF1 em pacientes com linfangioleiomiomatose (LAM) após o uso de doxiciclina, um conhecido inibidor de MMP, durante 12 meses. MÉTODOS: Ensaio clínico aberto de braço único no qual as pacientes com diagnóstico de LAM receberam doxiciclina (100 mg/dia) durante 12 meses. Elas foram submetidas a prova de função pulmonar completa, teste de caminhada de seis minutos, avaliação da qualidade de vida e coleta de amostras séricas e urinárias para dosagem de MMP-2, MMP-9 e VEGF-D antes do início do tratamento com doxiciclina e após 6 e 12 meses de tratamento. RESULTADOS: Trinta e uma pacientes com LAM receberam doxiciclina durante 12 meses. Embora tenha havido um bloqueio efetivo da MMP-9 urinária e da MMP-2 sérica após o tratamento, os níveis séricos de MMP-9 e VEGF-D permaneceram estáveis. Com base na resposta à doxiciclina (determinada pela variação do VEF1), as pacientes foram divididas em dois grupos: respondedoras (doxi-R; n = 13) e não respondedoras (doxi-NR; n = 18). As pacientes com alterações espirométricas leves apresentaram melhor resposta à doxiciclina. Os efeitos colaterais mais comuns foram epigastralgia, náusea e diarreia, todos de leve intensidade. CONCLUSÕES: Em pacientes com LAM, o tratamento com doxiciclina resulta em um bloqueio eficaz das MMP, além de melhorar a função pulmonar e a qualidade de vida daqueles com doença menos grave. No entanto, esses benefícios não parecem estar relacionados ao bloqueio das MMP, o que sugere um mecanismo de ação diferente. (Registro Brasileiro de Ensaios Clínicos - ReBEC; número de identificação RBR-6g8yz9 [http://www.ensaiosclinicos.gov.br]).

OBJECTIVE: To assess blockade of matrix metalloproteinase (MMP)-2 and MMP-9, as well as the variation in FEV1, in patients with lymphangioleiomyomatosis (LAM) treated with doxycycline (a known MMP inhibitor) for 12 months. METHODS: An open-label, single-arm, interventional clinical trial in which LAM patients received doxycycline (100 mg/day) for 12 months. Patients underwent full pulmonary function testing, a six-minute walk test, and quality of life assessment, as well as blood and urine sampling for quantification of MMP-2, MMP-9, and VEGF-D levels-at baseline, as well as at 6 and 12 months after the initiation of doxycycline. RESULTS: Thirty-one LAM patients received doxycycline for 12 months. Although there was effective blockade of urinary MMP-9 and serum MMP-2 after treatment, there were no significant differences between pre- and post-doxycycline serum levels of MMP-9 and VEGF-D. On the basis of their response to doxycycline (as determined by the variation in FEV1), the patients were divided into two groups: the doxycycline-responder (doxy-R) group (n = 13); and the doxycycline-nonresponder (doxy-NR) group (n = 18). The patients with mild spirometric abnormalities responded better to doxycycline. The most common side effects were mild epigastric pain, nausea, and diarrhea. CONCLUSIONS: In patients with LAM, doxycycline treatment results in effective MMP blockade, as well as in improved lung function and quality of life in those with less severe disease. However, these benefits do not seem to be related to the MMP blockade, raising the hypothesis that there is a different mechanism of action. (Brazilian Registry of Clinical Trials - ReBEC; identification number RBR-6g8yz9 [http://www.ensaiosclinicos.gov.br]).