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J Chao

Publications and source records attributed to J Chao.

At least 127 records · Page 7Linked to original sources
PubMed1996

Antisense inhibition of the brain kallikrein-kinin system.

We used antisense oligodeoxynucleotide (ODN) strategy, based on interference of information flow from gene to protein, to determine the role of kininogen and bradykinin B2 receptor genes in the pathogenesis of genetic hypertension in rats. Mean blood pressure of 9-week-old spontaneously hypertensive rats (SHR) increased 4 hours after acute intracerebroventricular injection of synthetic 18-mer antisense ODNs targeting the translation initiation codon of kininogen mRNA (from 164 +/- 5 to 181 +/- 4 mm Hg, P < .01) or bradykinin B2 receptor mRNA (from 161 +/- 5 to 185 +/- 8 mm Hg, P < .01) and then returned to basal levels within 24 hours. Prolonged vasopressor effects were observed after repeated injections of antisense ODN targeting kininogen mRNA. Antisense ODNs to kininogen and B2 receptor mRNAs increased blood pressure of normotensive Wistar-Kyoto rats only slightly compared with SHR (from 116 +/- 3 to 124 +/- 1 and from 116 +/- 2 to 126 +/- 4 mm Hg, respectively; P < .05). Cardiovascular responses were confirmed by the use of antisense ODNs targeted to bind to different non-overlapping regions of kininogen or B2 receptor mRNA. Microinjection of antisense ODN to B2 receptor mRNA into the nucleus tractus solitarii increased mean blood pressure in SHR and prevented the vasodepressor effect induced by intranuclear microinjection of bradykinin. No significant change in mean blood pressure was induced in either strain by intravenous injection of antisense ODNs or by central injection of sense or scrambled ODNs. A strong fluorescent signal was detected at the level of the hippocampus, thalamus, hypothalamus periventricularis, midbrain, and cerebrum 1 hour after central injection of fluorescein isothiocyanate-conjugated antisense ODNs. Kininogen levels were significantly lower in the brain of rats given intracerebroventricular antisense kininogen ODN compared with controls. Our results indicate that the brain kallikrein-kinin system plays a role in the central regulation of blood pressure and suggest that this system may exert a protective action against further elevations of blood pressure levels in SHR.

Animals↗
PubMed1996

Kallistatin in human ocular tissues: reduced levels in vitreous fluids from patients with diabetic retinopathy.

PURPOSE: Kallistatin is a serine proteinase inhibitor, which binds to tissue kallikrein and inhibits its proteolytic activity. This study is to determine the expression, cellular localization and the potential function of kallistatin in the eye. METHODS: Tissue kallikrein-kallistatin complex formation was performed to detect the kallikrein-binding activity in ocular tissues. Immunoreactive kallistatin was detected and quantified by an enzyme-linked immunosorbent assay using polyclonal antibody specific to human kallistatin. In situ hybridization histochemistry was employed to localize the kallistatin mRNA in human eyes using an antisense riboprobe of kallistatin. RESULTS: We have identified active kallistatin in the cornea, ciliary body, sclera, choroid, optic nerve, retina, vitreous and aqeous fluids. Kallistatin binds to tissue kallikrein and forms an SDS-stable complex. Immunoreactive kallistatin was identified in these tissues. Linear dose-dependent curves of the tissue extracts of the retina and choroid are parallel to that of purified human kallistatin, suggesting their immunological identity. The kallistatin mRNA was identified in the ciliary muscle, lens epithelial cells, all the layers of retina cells, optic nerve, choroid and vascular endothelial cells. These cells were not stained by the sense riboprobe under the same conditions, indicating the specificity of the hybridization. We also compared immunoreactive kallistatin levels in vitreous fluids from 18 patients with diabetic retinopathy and 17 non-diabetic subjects. The results show that diabetic subjects have significantly lower kallistatin levels (233.0 +/- 14.6 ng/mg protein) compared to non-diabetic subjects (334.1 +/- 26.9 ng/mg protein). CONCLUSIONS: Kallistatin is produced endogenously in the eye and the decrease in the vitreous kallistatin levels may be involved in diabetic retinopathy.

Adult↗
PubMed1996

High level of circulating human tissue kallikrein induces hypotension in a transgenic mouse model.

We established a unique transgenic mouse model in liver-targeted expression of human tissue kallikrein using a mouse albumin enhancer and promoter. Northern blot analysis and ELISA showed that human tissue kallikrein was predominantly expressed in the liver of transgenic mice and secreted into the circulation at a high level. The transcript was also detected in the kidney, pancreas, salivary gland and heart at a low level by reverse transcription-polymerase chain reaction followed by Southern blot analysis. Systolic blood pressures were measured by the tail-cuff method, all three independent transgenic mouse lines are hypotensive (84.6 +/- 1.0 mmHg, n = 17; 84.5 +/- 1.5 mmHg, n = 9; 83.1 +/- 0.8 mmHg, n = 13, P < 0.01) compared with the control mice (100.9 +/- 0.9 mmHg, n = 17). Administration of aprotinin, a potent tissue kallikrein inhibitor or Hoe 140, a bradykinin receptor antagonist, restored the blood pressure of transgenic mice but had no significant effect on control littermates. These studies show that over-production of tissue kallikrein in the circulation plays a role in blood pressure regulation.

Animals↗
PubMed1996

An aspartate residue in the extracellular loop of the N-methyl-D-aspartate receptor controls sensitivity to spermine and protons.

To study the role of acidic residues in modulation of NMDA receptors by spermine, we used site-directed mutagenesis of receptor subunits and voltage-clamp recording in Xenopus oocytes. Sixteen glutamate and aspartate residues, located in the first two thirds of the putative extracellular loop of the NR1A subunit, were individually mutated. This region of NR1A shows homology with bacterial amino acid binding proteins, a bacterial polyamine binding protein, and a bacterial spermidine acetyltransferase. Mutation of D669 to asparagine (D669N), alanine (D669A), or glutamate (D669E) abolished the "glycine-independent" form of spermine stimulation in heteromeric NR1A/NR2B receptors. These mutations also markedly reduced inhibition by ifenprodil and by protons at NR1A/NR2B receptors. Mutations at the equivalent position (D690) in NR1B, which contains the insert encoded by exon 5, reduced the pH sensitivity of NR1B/NR2B receptors. Thus, the effects of mutations at D669 are not prevented by the presence of exon 5, and the influence of exon 5 is not prevented by mutations at D669 (D690 in NR1B). Mutations at NR1A (D669) had little or no effect on the potencies of glutamate and glycine and did not alter voltage-dependent block by Mg2+ or the "glycine-dependent" form of spermine stimulation. Surprisingly, the D669N and D669A mutations, but not the D669E mutation, reduced voltage-dependent block by spermine at NR1A/NR2 receptors. Mutations in NR2B at a position (D668) equivalent to D669 did not alter spermine stimulation or sensitivity to pH and ifenprodil. However, mutations D668N and D668A but not D668E in NR2B reduced voltage-dependent block by spermine. Screening of the negative charges at NR1A(D669) and NR2B(D668) may be involved in voltage-dependent block by spermine. D669 in NR1A could form part of a binding site for polyamines and ifenprodil and/or part of the proton sensor of the NMDA receptor. Alternatively, this residue may be critical for coupling of modulators such as spermine, protons, and ifenprodil to channel gating.

Amino Acid Sequence↗
PubMed1996

Activation of N-methyl-D-aspartate receptors by glycine: role of an aspartate residue in the M3-M4 loop of the NR1 subunit.

Glutamate and glycine are coagonists that act at distinct sites to activate N-methyl-D-aspartate (NMDA) receptors. In the NR1 subunit of the NMDA receptor, mutation of D732 to glutamate (D732E), asparagine (D732N), alanine (D732A), or glycine (D732G) reduced the potency of glycine by > 4000-fold, but these mutations had no effect on sensitivity to glutamate. Mutations at NR1(D732) also changed sensitivity to the glycine-site agonists D-serine and D-alanine, reducing the potencies and, in some cases, the efficacies of these compounds. Thus, D-serine was a full agonist at the glycine site of receptors containing NR1(D732N) and NR1(D732A), a partial agonist at receptors containing NR1(D732G), and a competitive antagonist at receptors containing NR1(D732). Mutations at NR1(D732) had no effect or produced an increase in sensitivity to the glycine-site antagonists 6,7-dichloroquinoxaline-2,3-dione and 5,7-dichlorokynurenic acid. These mutations did not affect the reversal potential, voltage-dependent block by extracellular Mg2+, block by ifenprodil, or stimulation by spermine at NR1/NR2B receptors. NR2 subunits containing mutations at NR2A(D731) and NR2B(D732), which correspond to NR1(D732), did not produce functional receptors when coexpressed with NR1. Residue D732 in NR1 may be close to a glycine binding site on the NMDA receptor and may directly affect the properties of this site or be critical for coupling of glycine binding to channel activation.

Amino Acid Sequence↗
PubMed1995

Regulatory elements in the promoter region of the renal kallikrein gene in normotensive vs hypertensive rats.

The renal kallikrein-kinin system has been implicated in the pathogenesis of hypertension. The expression level of the renal kallikrein gene in the kidney is significantly lower in spontaneously hypertensive rats (SHR) as compared with that of normotensive (SD and WKY) rats. Deletion analysis showed that the fragment -356/-188 of the promoter contains a transcriptional silencer(s) and the GC rich region located between -77 and -187 is the minimal essential element for directing the expression of the CAT reporter gene in mouse L cells. In the kidney of normotensive vs hypertensive rats, the nuclear protein factors NF1/CTF and SP1 bind differently to the renal kallikrein promoter, but similarly in the salivary gland. The differential transcriptional regulation of the rat renal kallikrein gene in the kidney may be responsible for the genetic difference between normotensive and hypertensive rats.

Animals↗
PubMed1995

Molecular cloning, tissue-specific expression, and cellular localization of human prostasin mRNA.

We have purified a novel human serine proteinase, designated as prostasin, from seminal fluid (Yu et al., 1994). In the present study, we have cloned and characterized the full-length cDNA encoding prostasin and identified its tissue-specific expression and cellular localization. A cDNA fragment was obtained by polymerase chain reaction using degenerate oligonucleotide primers derived from the NH2-terminal and internal amino acid sequences. A full-length cDNA sequence encoding prostasin was obtained by amplification of the 5'- and 3'-ends of the cDNA. It contains a 1,032-base coding region, a 572-base 3'-noncoding region and a 138-base 5'-noncoding sequence. Prostasin cDNA encodes a protein of 343 amino acids, which consists of a 32-amino acid signal peptide and a 311-amino acid proprostasin. Proprostasin is then cleaved between Arg12 and Ile13 to generate a 12-amino acid light chain and a 299-amino acid heavy chain, which are associated through a disulfide bond. The deduced amino acid sequence of the heavy chain has 34-42% identity to human acrosin, plasma kallikrein, and hepsin. A potential N-glycosylation site at Asn127 and the catalytic triad of His53, Asp102, and Ser206 have been identified. The deduced prostasin has a unique 19-amino acid hydrophobic portion at the COOH terminus, which makes it suitable to anchor in the cell membrane. Carboxyl-terminal sequencing of purified prostasin indicates that the hydrophobic portion is removed and that there is a cleavage between Arg290 and Pro291 during secretion. Southern blot analysis, following a reverse transcription polymerase chain reaction, indicates that prostasin mRNA is expressed in prostate, liver, salivary gland, kidney, lung, pancreas, colon, bronchus, renal proximal tubular cells, and prostate carcinoma LNCaP cells. Cellular localization of prostasin mRNA was identified within epithelial cells of the human prostate gland by in situ hybridization histochemistry.

Amino Acid Sequence↗
PubMed1995

Molecular cloning, purification and in situ localization of human colon kallikrein.

We have cloned and characterized a full-length cDNA encoding tissue kallikrein from a human colon carcinoma cell line (T84). The nucleic acid sequence of the colon kallikrein cDNA is identical to that of renal/pancreatic or tissue kallikrein cDNA. Reverse-transcription PCR followed by Southern-blot analysis using specific oligonucleotide probes showed expression of tissue kallikrein in human colon, pancreas and kidney. Tissue kallikrein mRNA was localized in glandular epithelial cells (goblet cells) in colon by in situ hybridization histochemistry. Human colon kallikrein was purified to apparent homogeneity by DEAE-Sepharose Cl-6B, aprotinin-affinity, and HQ/M perfusion chromatography. The purified colon kallikrein migrated as a broad, 40-45 kDa band in SDS/PAGE and was recognized by antibodies to human tissue kallikrein. The linear displacement curves for the colon kallikrein in an RIA were parallel with the human tissue kallikrein standard curve, indicating their immunological identity. The N-terminal sequence of the purified colon kallikrein matches completely with that of purified urinary or tissue kallikrein. These results indicate that human colon kallikrein is transcribed from the tissue kallikrein gene.

Amino Acid Sequence↗
PubMed1995

Intramuscular delivery of rat kallikrein-binding protein gene reverses hypotension in transgenic mice expressing human tissue kallikrein.

The tissue kallikrein-kinin system has been postulated to play a role in blood pressure regulation. The activity of tissue kallikrein is controlled by a number of factors in vivo. Rat kallikrein-binding protein (RKBP) is a serine proteinase inhibitor which binds to and inhibits tissue kallikrein's activity in vitro. We have recently developed several hypotensive transgenic mouse lines which express human tissue kallikrein. In order to investigate the role of RKBP in blood pressure regulation, we delivered the RKBP to these transgenic mice by intramuscular injection. Expression of the RKBP was detected in skeletal muscle by reverse transcription-polymerase chain reaction and Southern blot analysis at 10, 20, 30, and 40 days post-injection. Immunoreactive RKBP levels in the muscle and serum of these mice were quantified by a RKBP-specific enzyme-linked immunosorbent assay and Western blot analysis. The levels of RKBP mRNA and immunoreactive protein were detectable at 10 days post-injection and increased significantly at 20 and 30 days. During this period, RKBP delivery significantly increased systemic blood pressure in the kallikrein transgenic mice to a level comparable to that of normotensive control mice. The RKBP and vector DNA delivery had no effect on the blood pressure of normotensive control mice. No serum antibodies to RKBP or its DNA were detected in the mice 40 days post injection. These results suggest that the increase of systemic blood pressure by RKBP delivery in these hypotensive transgenic mice may be mediated by inhibiting tissue kallikrein activity.

Animals↗
PubMed1995

Purification and characterization of tissue kallikrein-like proteinases from the black sea bass (Centropristis striata) and the southern frog (Rana berlandieri).

Serine proteinases were isolated from the pyloric caeca of the black sea bass (Centropristis striata) and the pancreas of the Southern frog (Rana berlandieri) and were purified to apparent homogeneity by aprotinin affinity column chromatography, reverse phase high performance liquid chromatography and gel filtration FPLC liquid chromatography to produce products with molecular masses of approximately 27,000 Da and isoelectric points from 4.2 to 5.0. Both enzymes were kallikrein-like and were bound by diisopropylfluorophosphate; had pH optima from 9 to 10; showed high specificity for the hydrolysis of arginine peptide bonds and low to moderate affinity for lysine bonds at the P1 substrate recognition sites; were inhibited by aprotinin, benzamidine, leupeptin, and soybean trypsin inhibitor; generated kinin from kininogen and were highly stable at room temperature. Differences between the enzymes were observed relative to their hydrophobicities, substrate specificities, stabilities at acidic pHs in the presence and absence of calcium, and the amounts of kinin generated from kininogen. Many of the fish trypsins, previously identified as anionic trypsins, may actually be more kallikrein-like.

Amino Acid Sequence↗
PubMed1995

Cellular localization of tissue kallikrein and kallistatin mRNAs in human kidney.

The renal kallikrein-kinin system has been implicated in the regulation of blood pressure and sodium/water excretion. The activity of renal kallikrein is controlled by a number of factors in vivo. Kallistatin is a newly identified serine proteinase inhibitor (serpin) which binds to tissue kallikrein and inhibits its enzymatic activity in vitro. To understand the role of kallistatin in modulating tissue kallikrein's function in vivo, we examined the anatomical relationship between human tissue kallikrein and kallistatin in the kidney by in situ hybridization histochemistry. Tissue kallikrein and kallistatin gene transcripts were identified using digoxigenin-labeled riboprobes at the cellular level. Antisense and sense riboprobes corresponding to the 3' region of the human kallikrein and kallistatin mRNAs were synthesized by in vitro transcription and used for hybridization. Using an antisense kallikrein riboprobe, sites of kallikrein synthesis were localized in the distal tubules, collecting ducts and Henle's loops of the kidney. To a lesser degree, juxtaglomerular cells were also stained. Kallistatin mRNA was found at the same sites where kallikrein mRNA was localized. The most intense signals of both kallikrein and kallistatin were seen in the distal tubules and collecting ducts. Hybridization was specific for the target mRNA since sense kallikrein or kallistatin riboprobe did not bind to the sections. Immunoreactive human renal kallikrein and kallistatin levels were measured in the kidney and urine by immunoassays using specific antibodies. Co-localization of kallikrein and kallistatin mRNA in the kidney suggests a potential role of kallistatin in regulating tissue kallikrein's function.

Carrier Proteins↗
PubMed1995

Carbamazepine but not valproate induces bupropion metabolism.

Bupropion (BUP) may be less likely than other antidepressants to cause switches into mania and rapid cycling, suggesting utility in bipolar disorder. The combination of BUP with the mood-stabilizing anticonvulsants carbamazepine (CBZ) or valproate (VPA) is a strategy that might further lessen the risk of mania. CBZ induces, and to a lesser extent VPA inhibits the hepatic metabolism of various medications, but their effects on BUP have not been previously studied. Inpatients with mood disorders had pharmacokinetic profiles of BUP and metabolites assessed after single, oral, 150-mg doses of BUP while receiving placebo (N = 17) or during chronic blind CBZ (N = 12) or VPA (N = 5) monotherapy. CBZ but not VPA therapy decreased BUP peak concentrations (Cmax) by 87% (p < 0.0001) and 24-h area under the curve (AUC) by 90% (p < 0.0001), threohydrobupropion Cmax by 81% (p <0.0009) and AUC by 86% (p < 0.002), and erythropydrobupropion Cmax by 86% (p < 0.05) and AUC by 96% (p < 0.05). CBZ increased hydroxybupropion (H-BUP) Cmax by 71% (p < 0.007) and AUC by 50% (p < 0.09) and H-BUP AUC by 94% (p < 0.02). Thus, CBZ markedly decreased BUP and increased H-BUP concentrations, whereas VPA did not affect BUP but increased H-BUP concentrations. Further studies are required to determine how these differential effects of CBZ and VPA on BUP pharmacokinetics influence the tolerability and efficacy of combination therapies with these agents.

Adult↗
PubMed1995

Tacrolimus analysis: a comparison of different methods and matrices.

We determined the through blood and plasma concentrations of tacrolimus from the day of transplantation through 30 days posttransplantation in four liver and four kidney transplant patients by three different methods. The first method involved a solid phase extraction of the blood or plasma using Sep-Pak columns (SPs) followed by quantitation of tacrolimus using an enzyme-linked immunosorbent assay (ELISA); the second method involved a liquid-liquid extraction using methylene chloride (MC) followed by quantitation of tacrolimus using the ELISA, and the third method involved a high-performance liquid chromatography (HPLC) fractionation of the extract obtained from the solid-phase extraction and quantitation of tacrolimus in the fractions by ELISA. The trough plasma tacrolimus concentrations ranged from 0.1 to 5.2 ng/ml. While the trough plasma concentrations of tacrolimus were similar and independent of the method of analysis in kidney transplant patients and in liver transplant patients with normal biochemical profile, in patients with liver dysfunction, tacrolimus plasma concentrations were higher when measured by SP-ELISA and MC-ELISA methods as compared to the HPLC-ELISA method. In plasma samples obtained from liver transplant patients with liver dysfunction, the presence of some metabolites that cross-reacted with the antibody used in the ELISA could be documented in the HPLC fraction corresponding to the metabolites. This indicates that while tacrolimus metabolites that cross-react significantly with the antibody used in the ELISA do not accumulate in kidney transplant patients, they can appear in the plasma of patients, they can appear in the plasma of patients with liver dysfunction. The trough blood tacrolimus concentrations in patients were significantly higher than the corresponding plasma concentrations and ranged from 1.4 to 107 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed1995

Influences of secretory activities in rat submandibular glands on tissue kallikrein circulating in the blood.

Changes in serum levels of rat tissue kallikrein (rK1) in venous blood were measured, using a newly developed radioimmunoassay, before and after autonomic nerve stimulations of submandibular salivary secretion. rK1 secreted into saliva under these conditions was measured by radioimmunoassay and by enzymic activity assay, using the fluorogenic peptide substrate D-Val-Leu-Arg-7-amino-4-trifluoromethylcoumarin (AFC). Following an overnight fast, serum rK1 concentration was 30-40 ng ml-1. Unilateral electrical stimulation of the submandibular sympathetic nerve supply (at 50 Hz in bursts of 1 s every 10 s for 60 min) evoked a small flow of saliva with a very high rK1 concentration, resulting in a large output of rK1 of 2104.4 +/- 603.5 micrograms (n = 6). Such stimulation caused a large degranulation of granular duct cells and a corresponding reduction in glandular rK1 content. Unilateral electrical stimulation of the parasympathetic nerve supply (at 5 Hz continuously for 60 min) evoked a copious flow of saliva with a very low rK1 concentration, resulting in a low output of rK1 (18.1 +/- 4.9 micrograms; n = 6). Despite these large differences in salivary outputs of rK1, serum concentrations of rK1 were increased similarly following either sympathetic or parasympathetic stimulation by 48 and 46%, respectively. If the submandibular duct was briefly obstructed during sympathetic stimulation, inducing leakage and glandular oedema, then serum rK1 increased greatly (40-fold); a similar increase to that seen by others in previous studies without deliberate obstruction. Four days after bilateral submandibular-sublingual sialadenectomy serum rK1 concentration was reduced by approximately 50%. The results indicate that submandibular glands normally contribute to circulating levels of rK1 in rats, but this contribution is independent of the amounts of rK1 secreted into saliva by sympathetically induced exocytosis, and is likely to arise from basal vesicular transport. However, if glandular leakage occurs during sympathetic stimulation of submandibular secretion this then causes increases in the circulating levels of rK1 that correlate with the large amounts being secreted into saliva.

Animals↗
PubMed1995

Muscle delivery of human kallikrein gene reduces blood pressure in hypertensive rats.

We recently found that transgenic mice expressing human tissue kallikrein develop sustained hypotension. The result suggests that a continuous supply of human tissue kallikrein could have a prolonged effect on blood pressure reduction. In the present study, we investigated the potential of using human tissue kallikrein for gene therapy by injecting a kallikrein gene construct into the skeletal muscle of spontaneously hypertensive rats. Expression of the human tissue kallikrein messenger RNA in spontaneously hypertensive rats was identified by reverse transcription-polymerase chain reaction with Southern blot. Human tissue kallikrein was detected in the injected animals by an enzyme-linked immunosorbent assay. Injection of the human kallikrein gene into spontaneously hypertensive rats caused a significant reduction of systemic blood pressure, ranging from 15 to 26 mm Hg, compared with the control group. The differences were significant 1 week after the injection and continued for more than 2 months. Blood pressure reduction could be reversed after the administration of the bradykinin antagonist Hoe 140. The results indicate that somatic delivery of the human tissue kallikrein gene induces a sustained reduction of systemic blood pressure in spontaneously hypertensive rats. The present study raises the possibility of applying kallikrein gene therapy to the treatment of human hypertensive diseases.

Animals↗
PubMed1995

Human atrial natriuretic peptide gene delivery reduces blood pressure in hypertensive rats.

Chronic infusion of atrial natriuretic peptide (ANP) has been shown to cause natriuresis, diuresis, and hypotension in rats and humans. We explored the effect of a continuous supply of ANP by somatic ANP delivery on genetically hypertensive rats. A DNA construct containing the human ANP gene fused to the Rous sarcoma virus 3'-long terminal repeat (RSV-LTR) was injected intravenously into spontaneously hypertensive rats (SHR) through the tail vein. Expression of human ANP in SHR was identified in the heart, lung, and kidney by radioimmunoassay and reverse transcription-polymerase chain reaction followed by Southern blot analysis. A single injection of naked ANP plasmid DNA (12.3 kb) caused a significant reduction of systemic blood pressure in young SHR (4 weeks old), and the effect continued for 7 weeks. The differences were significant at 1 to 2 weeks (n = 6, P < .05) and 3 to 6 weeks after injection (n = 6, P < .01) A maximal blood pressure reduction of 21 mm Hg in young SHR was observed 5 weeks after injection with ANP DNA (159.4 +/- 3.02 mm Hg, mean +/- SEM, n = 6) compared with SHR injected with vector DNA alone (180.2 +/- 3.02 mm Hg, mean +/- SEM; n = 6; P < .01). Somatic gene delivery of human ANP DNA had no effect on the blood pressure of adult SHR (12 weeks old). After ANP gene delivery, there were significant increases in urinary volume and urinary potassium output (n = 6, P < .05) but not in body weight, heart rate, water intake, urinary sodium output, urinary creatine, and urinary protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

Direct gene delivery of human tissue kallikrein reduces blood pressure in spontaneously hypertensive rats.

Hypertension is a multigene and multifactorial disorder affecting approximately 25% of the population. To demonstrate potential therapeutic effects of human tissue kallikrein in hypertension, spontaneously hypertensive rats were subjected to somatic gene therapy. Two human tissue kallikrein DNA constructs, one under the promoter control of the metallothionein metal response element and the other under the control of the Rous sarcoma virus 3'-LTR, were generated. We delivered naked DNA constructs into spontaneously hypertensive rats via intravenous injection. The expression of human tissue kallikrein in rats was identified in the heart, lung, and kidney by reverse transcription polymerase chain reaction followed by Southern blot analysis and an ELISA specific for human tissue kallikrein. A single injection of both human kallikrein plasmid DNA constructs caused a sustained reduction of blood pressure which began 1 wk after injection and continued for 6 wk. A maximal effect of blood pressure reduction of 46 mmHg in rats was observed 2-3 wk after injection with kallikrein DNA as compared to rats with vector DNA (n = 6, P < 0.05). The hypotensive effect caused by somatic gene delivery of human tissue kallikrein in hypertensive rats is reversed by subcutaneous injection of aprotinin, a potent tissue kallikrein inhibitor. No antibodies to either human tissue kallikrein or kallikrein DNA were detected in rat sera after injection of the human kallikrein gene. These results show that direct gene delivery of human tissue kallikrein causes a sustained reduction in systolic blood pressure in genetically hypertensive rats and indicate that the feasibility of kallikrein gene therapy for treating human hypertension should be studied.

Animals↗