Systemic and Portal Vein Delivery of Human Kallikrein Gene Reduces Blood Pressure in Hypertensive Rats

Abstract

There is an inverse correlation between systemic blood pressure and urinary kallikrein levels in humans and hypertensive animal models, suggesting that the tissue kallikrein-kinin system plays an important role in blood pressure regulation. In this study, we explored the potential of human kallikrein gene delivery on blood pressure reduction in spontaneously hypertensive rats (SHR). The human tissue kallikrein gene or cDNA was placed under the control of following promoters: the metallothionein gene metal response-element (MRE-pHK), albumin gene (ALB-pHK), Rous sarcoma virus 3' long terminal repeat (LTR) (RSV-cHK), and cytomegalovirus (CMV-cHK). A single injection of these kallikrein DNAs results in a significant reduction of blood pressure in SHR, which lasts for 5-6 weeks. Systemic delivery of CMV-cHK, RSV-cHK, and MRE-pHK has a greater effect on blood pressure reduction than ALB-pHK, whereas intraportal vein gene delivery of ALB-pHK is more effective than the other kallikrein DNA constructs. The degree of blood pressure reduction depends on the amount of administered DNA and the age of the animals. Reduction of blood pressure was observed in adult, but not young, SHR. The expression of human tissue kallikrein in rats was identified by an ELISA that is specific for human tissue kallikrein. No antibodies to either human tissue kallikrein or its DNA were detected in rat sera after somatic gene delivery. These results show that somatic gene delivery of human tissue kallikrein causes a lowering effect of systolic blood pressure in genetically hypertensive rats and provide valuable information for kallikrein gene therapy in the treatment of hypertension.

Prolonged hypotensive effect of human tissue kallikrein gene delivery and recombinant enzyme administration in spontaneous hypertension rats

“…This was further supported by our experiments, in which no overt side effects and significant immune responses were observed during the experimental periods. Our data further suggest that non-vial delivery of KLK1 gene is a feasible way of treating human hypertension (Chao et al, 1996;1997). In both pilot and formal experiments, systemic delivery of pcDNA3-KLK1 plasmid into SHR caused significant decrease in systolic pressure, which lasted for up to 3 weeks in a dose-dependent manner following first injection.…”

Kallikrein Gene Delivery Attenuates Hypertension and Cardiac Hypertrophy and Enhances Renal Function in Goldblatt Hypertensive Rats

“…27 Previously, we reported that systemic or local delivery of human tissue kallikrein in spontaneously hypertensive rats using naked plasmid DNA vector could cause a prolonged delay in blood pressure increase. [12][13][14][15] The hypotensive effect of kallikrein gene delivery was abolished by incatibant (Hoe 140), a specific bradykinin B 2 receptor antagonist, suggesting that the blood pressure-lowering effect is mediated by the bradykinin B 2 receptor. 13 Human tissue kallikrein and its mRNA can be identified in rat kidney and urine after kallikrein gene delivery.…”

“…14 The expression of human tissue kallikrein cDNA, flanking the entire coding sequence, was under the control of the cytomegalovirus enhancer/ promoter and by the bovine growth hormone gene polyadenylation signal sequence. Plasmid pAd.CMV-cHK was constructed by inserting the NaeI/NruI released fragment of CMV-cHK into the adenoviral shuttle vector pAdLink.1 at an EcoRV site.…”

“…To further examine the effect of kallikrein gene expression on blood pressure regulation, we delivered the human tissue kallikrein gene into genetically hypertensive rats and found that somatic gene delivery of human tissue kallikrein caused a prolonged reduction of blood pressure for up to 8 weeks. [12][13][14][15] In this study, we evaluated the effectiveness of tissue kallikrein gene delivery on blood pressure reduction in 2K1C Goldblatt hypertensive rats. In this experimental Goldblatt hypertensive model, the intrarenal RAS is upregulated during the initial phase of 2K1C hypertension.…”

Prevention of Diabetes-Induced Microangiopathy by Human Tissue Kallikrein Gene Transfer

“…19 In the transcription unit, the hTK sequence is followed by the bovine growth hormone gene polyadenylation signal sequence, and expression is controlled by the cytomegalovirus enhancer/promoter.…”