Erasmus MC, Department of Medical Microbiology and Infectious Diseases, Rotterdam, The Netherlands.
Mycetoma Research Centre, Soba University Hospital, University of Khartoum, Khartoum, Sudan.
PLoS Negl Trop Dis. 2014 Mar 27;8(3):e2754. doi: 10.1371/journal.pntd.0002754. eCollection 2014 Mar.
Madurella mycetomatis is the main causative organism of eumycetoma, a persistent, progressive granulomatous infection. After subcutaneous inoculation M. mycetomatis organizes itself in grains inside a granuloma with excessive collagen accumulation surrounding it. This could be contributing to treatment failure towards currently used antifungal agents. Due to their pivotal role in tissue remodelling, matrix metalloproteinases-2 (MMP-2) and 9 (MMP-9) or tissue inhibitor of metalloproteinases (TIMP) might be involved in this process. Local MMP-2 and MMP-9 expression was assessed by immunohistochemistry while absolute serum levels of these enzymes were determined in mycetoma patients and healthy controls by performing ELISAs. The presence of active MMP was determined by gelatin zymography. We found that both MMP-2 and MMP-9 are expressed in the mycetoma lesion, but the absolute MMP-2, -9, and TIMP-1 serum levels did not significantly differ between patients and controls. However, active MMP-9 was found in sera of 36% of M. mycetomatis infected subjects, whereas this active form was absent in sera of controls (P<0.0001). MMP-2, MMP-9, and TIMP-1 polymorphisms in mycetoma patients and healthy controls were determined through PCR-RFLP or sequencing. A higher T allele frequency in TIMP-1 (+372) SNP was observed in male M. mycetomatis mycetoma patients compared to controls. The presence of active MMP-9 in mycetoma patients suggest that MMP-9 is activated or synthesized by inflammatory cells upon M. mycetomatis infection. Inhibiting MMP-9 activity with doxycycline could prevent collagen accumulation in mycetoma, which in its turn might make the fungus more accessible to antifungal agents.
马杜拉放线菌是真菌性肉芽肿感染——足菌肿的主要病原体。在皮下接种后，马杜拉放线菌会在肉芽肿内形成团块，周围有大量胶原过度堆积。这可能是导致目前使用的抗真菌药物治疗失败的原因之一。由于基质金属蛋白酶-2（MMP-2）和 9（MMP-9）或基质金属蛋白酶组织抑制剂（TIMP）在组织重塑中起关键作用，它们可能参与了这一过程。通过免疫组织化学评估局部 MMP-2 和 MMP-9 的表达，通过酶联免疫吸附试验（ELISA）测定这些酶在足菌肿患者和健康对照者的血清中的绝对水平。通过明胶酶谱法测定活性 MMP。我们发现 MMP-2 和 MMP-9 均在足菌肿病变中表达，但患者和对照组之间的 MMP-2、-9 和 TIMP-1 血清水平没有显著差异。然而，在 36%的马杜拉放线菌感染患者的血清中发现了活性 MMP-9，而在对照组的血清中则没有（P<0.0001）。通过 PCR-RFLP 或测序确定了足菌肿患者和健康对照者的 MMP-2、MMP-9 和 TIMP-1 多态性。与对照组相比，马杜拉放线菌足菌肿男性患者 TIMP-1（+372）SNP 的 T 等位基因频率更高。在马杜拉放线菌感染后，炎症细胞可能会激活或合成 MMP-9。用强力霉素抑制 MMP-9 的活性可以防止足菌肿中的胶原积累，从而使真菌更容易受到抗真菌药物的作用。
