An in vivo effect of recombinant human secretory leukocyte protease inhibitor in myocardial ischaemia/reperfusion injury

Name: Podsawee Mongkolpathumrat

ThaSH: Myocardial infarction

ThaSH: Post-ischaemic treatment

ThaSH: Cardioprotection

ThaSH: Anti-protease deficient

Abstract: Proteolysis by the protease enzyme aggravates myocardial ischaemia/reperfusion (I/R) injury by expanding the injured area and inducing inflammation. These lead to impaired cardiac function and cardiac structure, which contribute to cardiac remodelling and heart failure. Inhibition of proteases seems to provide therapeutic benefit. Our previous study demonstrated that giving recombinant human secretory leukocyte protease inhibitor (rhSLPI) by means of overexpression of the rhSLPI gene or treatment with recombinant protein of human SLPI provided a cytoprotective effect against I/R injury. Unfortunately, the information mostly came from an in vitro and an ex vivo experiment with pre-ischaemic treatment. Nevertheless, the roles and consequences of rhSLPI in the post-ischemic period, especially in an in vivo model, as well as post-ischaemic cardiac remodelling and hypertrophy have not been intensively investigated. In this study, recombinant human (rh)SLPI was administered intravenously during left anterior descending (LAD) coronary artery ligation and the onset of reperfusion. The results showed that post-ischaemic treatment with rhSLPI could significantly reduce infarct size, lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) activity, inflammatory cytokines, and protein carbonyl levels, as well as improve cardiac functions. The intracellular mechanistic explanation for the cardioprotection is due to inhibition of p38 MAPK phosphorylation, downregulation of Bax, caspase-3 and 8 protein levels, and activation of Akt and ERK1/2 phosphorylation. In summary, this is the first report showing the cardioprotective effects against myocardial I/R injury of post-ischaemic treatments with rhSLPI in vivo. Although the cardioprotective effect of SLPI is proven, it remains unclear whether the cardioprotective effect of SLPI seen in our previous work is due to inhibition of protease enzymes. Therefore, an anti-protease deficient mutant SLPI has been developed to investigate if the cardioprotective effect is dependent upon its anti-protease activity. In this part, recombinant protein of anti-protease deficient mutant SLPI (L72K, M73G, L74G), or mt-SLPI, was intravenously administered to rats after they were subjected to LAD ligation. The results showed that mt-SLPI could significantly reduce cardiac cell death, and intracellular reactive oxygen species (ROS) production against an in vitro simulated I/R injury. Furthermore, post-ischaemic treatment of mt-SLPI could significantly reduce infarct size and cardiac biomarkers such as lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) activity, improve cardiac functions, attenuate I/R induced-p38 MAPK phosphorylation, and reduce apoptotic regulatory protein levels, including Bax, cleaved-Caspase-3 and total Capase-8, in rats subjected to an in vivo I/R injury. Additionally, the beneficial effect of mt-SLPI was not significantly different from wild-type (wt-SLPI). Thus, anti-protease deficient mutant SLPI could also provide a cardioprotective effect, which could be more clinically beneficial in terms of providing cardioprotection without interfering with basal serine protease activity. In summary, post-ischemic treatment of recombinant human SLPI could be used as a future novel therapeutic alternative for myocardial I/R injury.

NARESUAN UNIVERSITY. NARESUAN UNIVERSITY LIBRARY

Address: PHITSANULOK

Email: library@nu.ac.th

Name: Sarawut Kumphune

Role: Assistant Professor

Created: 2566

Modified: 2023-04-25

Issued: 2023-04-25

วิทยานิพนธ์/Thesis

application/pdf

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Biomedical Sciences

Grantor: มหาวิทยาลัยนเรศวร

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