Altered expression of MMP9 and TIMP1 leads to impaired placentation in early onset preeclamptic patients: a case control study

Introduction Matrix metalloproteinases (MMPs) specifically MMP-9 is a key regulator of vascular and uterine spiral artery remodelling and its activity is controlled at multiple levels, including gene transcription, activation of its latent forms and endogenous inhibition by tissue inhibitors of metalloproteinases [TIMPs (specifically TIMP-1)]. Alteration in MMP-9 and TIMP-1 expression may contribute to uterine and vascular dysfunction leading to adverse pregnancy outcomes such as Preeclampsia (PE). Depending on time, PE is classified as early-onset preeclampsia, which is diagnosed before 34 weeks of gestation, or late-onset preeclampsia, which is diagnosed after 34 weeks. Early-onset preeclampsia (EOPE) is a severe obstetrics disease which threatens mother and foetus. Therefore, in the present study, we aimed to investigate the levels of MMP-9 and its inhibitor TIMP-1 in the placentae of EOPE patients and their maternal age matched normotensive, non-proteinuric controls at both mRNA and protein levels. Methods A total of 30 caesarean delivered placentae (15 EOPE patients and 15 controls) were collected from Department of Obstetrics and Gynaecology, AIIMS, New Delhi after taking permission from Institute Ethics Committee. MMP-9 and TIMP-1 protein expression was observed by immunohistochemistry and immunofluorescence stainings. Gelatin Gel Zymography was done to evaluate MMP-9 activity and Western Blot was done for the quantification of MMP-9 and TIMP-1 proteins. mRNA levels of MMP-9 and TIMP-1 were determined by qRT-PCR Results Immunohistochemistry and Immunofluorescence staining discerned stronger expression of MMP-9 in normotensive placentae as compared to EOPE placentae whereas stronger expression of TIMP-1 was seen in EOPE placentae in comparison to those of normotensive placentae. Gelatin Gel Zymography reflected that MMP-9 activity was found elevated in maternal placental side in normotensive placentae as compared to EOPE placentae. Western Blot analysis revealed that protein expression of MMP-9 was elevated whereas for that of TIMP-1 was reduced in normotensive placentae in comparison to EOPE placentae. mRNA expression of MMP-9 was found up-regulated whereas for that of TIMP-1 was down-regulated in normotensive placentae as compared to EOPE placentae. Conclusion The present study implies that aberrant functioning of MMP-9 and TIMP-1 in EOPE patients contribute to impaired placentation which might be relevant for possible future screening programs in order to predict and to design therapies for early onset preeclamptic patients.