Involvement of miR-9/MCPIP1 axis in PDGF-BB-mediated neurogenesis in neuronal progenitor cells

Highly conserved microRNA-9 (miR-9) has a critical role in various cellular processes including neurogenesis. However, its regulation by neurotropins that are known to mediate neurogenesis remains poorly defined. In this study, we identify platelet-derived growth factor-BB (PDGF-BB)-mediated upregulation of miR-9, which in turn downregulates its target gene monocyte chemotactic protein-induced protein 1 (MCPIP1), as a key player in modulating proliferation, neuronal differentiation as well as migration of neuronal progenitor cells (NPCs). Results indicate that miR-9-mediated NPC proliferation and neuronal differentiation involves signaling via the nuclear factor-kappa B (NF-κB) and cAMP response element-binding protein (CREB) pathways, and that NPC migration involves CREB but not the NF-κB signaling. These findings thus suggest that miR-9-mediated downregulation of MCPIP1 acts as a molecular switch regulation of neurogenesis.

Porphyromonas gingivalis promotes monocyte migration by activating MMP-9

BACKGROUND AND OBJECTIVE

The migration of monocytes into the local environment is crucial for their maturation into macrophages or osteoclasts in the pathogenesis of periodontal disease. The objective of this study was to investigate the role and mechanisms mediated by Porphyromonas gingivalis in promoting the migration of monocytes by regulating MMP-9 and TIMP-1 expression.

MATERIAL AND METHODS

Human THP1 monocytes were treated with culture supernatant derived from P. gingivalis (ATCC 33277) for 24 h. Zymography, western blot analysis and quantitative PCRs were performed to analyse protein and mRNA levels of MMP-9. Protein and mRNA levels of TIMP-1 from monocytes treated with or without P. gingivalis were determined as well. Transwell migration assay was carried out to analyse the effect of P. gingivalis on the migration of human peripheral blood CD14-positive monocytes. An MMP inhibitor (GM6001) and a proteinase inhibitor (leupeptin) were used to determine the role of MMP-9 in P. gingivalis supernatant- and lipopolysaccharide-induced monocyte migration.

RESULTS

In zymography and western blot, an 82 kDa band of active MMP-9 emerged in P. gingivalis-treated monocyte culture media in a dose-dependent manner, in addition to the MMP-9 proenzyme (92 kDa) band expressed in control cell culture media. P. gingivalis supernatant increased both the protein and the mRNA levels of MMP-9 and TIMP-1. P. gingivalis supernatant, but not its lipopolysaccharide, increased the migratory ability of CD14-positive monocytes. The increased migratory ability of P. gingivalis-treated monocytes was partly inhibited by leupeptin (200 μg/mL) and completely antagonized by the MMP inhibitor GM6001 (100 nm). Lipopolysaccharide of P. gingivalis increased protein and mRNA levels of MMP-9 in monocytes, but had no effect on the migratory ability or MMP-9 activation.

CONCLUSION

P. gingivalis supernatant increased the migratory ability of monocytes, in part, by increasing activation and expression of MMP-9.

The CHOICE trial: adalimumab demonstrates safety, fistula healing, improved quality of life and increased work productivity in patients with Crohn's disease who failed prior infliximab therapy

BACKGROUND

Adalimumab induces and maintains remission in adults with Crohn's disease.

AIM

To evaluate safety, fistula healing, quality of life and work productivity in adalimumab-treated patients who failed infliximab, including primary nonresponders.

METHODS

After a ≥8-week infliximab washout, patients with moderate-to-severe Crohn's disease received open-label adalimumab as induction (160/80 mg at weeks 0/2) and maintenance (40 mg every other week) therapies. At/after 8 weeks, patients with flare/nonresponse could receive weekly therapy. Minimum study duration was 8 weeks, continuing until the commercial availability of adalimumab for Crohn's disease.

RESULTS

Of 673 patients enrolled, 17% were infliximab primary nonresponders and 83% were initial responders. Three percent of patients had serious infections (mainly abscesses). Complete fistula healing was achieved by 34/88 (39%) patients with baseline fistulas. Improvements in quality of life and work productivity were sustained from week 4 to week 24 for all patients, as well as the subgroup of primary nonresponders.

CONCLUSIONS

Blinded clinical trials have shown adalimumab to be both an effective first-line therapy for anti-TNF-naïve patients and an important treatment option for infliximab-refractory or -intolerant patients. This trial presents open-label experience to support further the safety and effectiveness of adalimumab in patients who failed infliximab therapy, including primary nonresponders (NCT00338650).

Adalimumab sustains clinical remission and overall clinical benefit after 2 years of therapy for Crohn's disease

BACKGROUND

In the randomized, double-blind, placebo-controlled CHARM trial, adalimumab was more effective than placebo in maintaining clinical remission for patients with moderate-to-severe Crohn's disease (CD) through 56 weeks.

AIM

To substantiate the long-term safety and clinical benefits of adalimumab through 2 years of therapy in CHARM and its open-label extension (ADHERE).

METHODS

Patients entering ADHERE on blinded therapy received adalimumab 40 mg every other week (eow). Patients who had already moved to open-label adalimumab eow or weekly in CHARM continued their regimens. Data were analysed by originally randomized treatment group at CHARM baseline (adalimumab 40 mg eow, adalimumab 40 mg weekly, or placebo), regardless of whether patients entered ADHERE or received open-label adalimumab (eow or weekly).

RESULTS

After up to 2 years of therapy, 37.6%, 41.9% and 49.8% of patients originally randomized to placebo, adalimumab eow and adalimumab weekly, respectively, were in clinical remission. All groups experienced sustained improvements on the Inflammatory Bowel Disease Questionnaire. Decreasing hazard rates for both all-cause and CD-related hospitalizations were observed over time. Over a 2-year period, the rates of serious adverse events and malignancies (33.3 and 1.1 events/100-patient-years respectively) were similar to those observed during the overall adalimumab CD clinical development programme.

CONCLUSIONS

Adalimumab demonstrated sustained maintenance of clinical remission, improvements in quality of life and reductions in hospitalization during long-term treatment for CD, with no new safety concerns identified.

Systematic review: the costs of ulcerative colitis in Western countries

BACKGROUND

Early onset and complications such as hospitalization and surgery contribute to the economic burden of ulcerative colitis.

AIM

To review systematically the literature on costs of ulcerative colitis in Western countries.

METHODS

Studies estimating costs of ulcerative colitis in Western countries were identified using Medline, EMBASE and ISI Web of Science and were rated based on relevance and reliability of estimates. All costs were adjusted to 2008 currency values. A parallel review focused on the impact of disease severity on costs, hospitalizations and surgeries.

RESULTS

Estimated annual per-patient direct medical costs of ulcerative colitis ranged from $6217 to $11,477 in the United States and from euro8949 to euro10,395 in Europe. Hospitalizations accounted for 41-55% of direct medical costs. Indirect costs accounted for approximately one-third of total costs in the United States and 54-68% in Europe. Total economic burden of ulcerative colitis was estimated at $8.1-14.9 billion annually in the United States and at euro12.5-29.1 billion in Europe; total direct costs were $3.4-8.6 billion in the United States and euro5.4-12.6 billion in Europe. Direct costs, hospitalizations and surgeries increased with worsening disease severity.

CONCLUSIONS

Ulcerative colitis is a costly disease. Hospitalizations contribute significantly to direct medical costs, and indirect costs are considerable, having previously been substantially underestimated.

Gene therapy for hypertension: a review of potential targets

Somatic gene delivery approaches have received wide attention as a new technique for studying gene expression and as a potential therapeutic tool in treating both inherited and acquired diseases. Recent studies using nonviral and viral vectors have shown great promise for gene therapy in hypertensive diseases. Potential targets for prospective gene therapy in hypertension include vasopressor renin-angiotensin system components and a number of vasodilator polypeptides such as tissue kallikrein-kinin, atrial natriuretic peptide, adrenomedullin and nitric oxide synthase. Antisense inhibition with oligonucleotides or cDNAs encoding renin, angiotensinogen, angiotensin-converting enzyme and angiotensin receptors has been shown to cause a prolonged blood pressure reduction in spontaneously hypertensive rats. To evaluate the therapeutic potential of vasodilator proteins or peptides in high blood pressure, we delivered the genes encoding human tissue kallikrein, atrial natriuretic peptide, nitric oxide synthase, and adrenomedullin into hypertensive rat models and showed that a single injection resulted in a significant and sustained reduction of blood pressure for several weeks. The potency and duration of blood pressure reduction depends on the dose and the promoter of the gene administered, age and sex of the hypertensive animals as well as the vehicle used for gene delivery. Somatic gene transfer of human tissue kallikrein or atrial natriuretic peptide not only attenuated hypertension but also exerted a protective effect against salt-induced renal damage and cardiac hypertrophy in Dahl salt-sensitive rats after high salt loading. These results suggest that the application of antisense inhibition of vasopressors, or gene delivery of vasodepressors for gene therapy, may have potential in treating human hypertension, and cardiovascular and renal disorders.

Real-time PCR analysis of the heat-shock response of Acidithiobacillus ferrooxidans ATCC 23270

As one of the most important bioleaching bacterial species, Acidithiobacillus ferrooxidans is subjected to different kinds of environmental stress such as temperature changes, presence of some toxic heavy metals or pH changes, which normally take place in bioleaching operations and may affect the activity of the bacteria. To obtain further knowledge of the protective mechanisms employed by A. ferrooxidans in response to elevated growth temperature, temporal gene expression profiles were examined in cells subjected to heat stress by using real-time PCR. The majority of predicted genes, including those encoding chaperones and heat-shock proteins, were significantly up-regulated (P < 0.05 and the fold change >or= 2.0) over a 25-min period after upshift to the heatshock temperature (from 30 to 42 degrees C) and then decrease to readjust their transcript levels to a new steady state at 42 degrees C. Finally, based on the gene expression data and computational analysis, a putative regulatory site having T-T-T-T-T-T-n-n in the -35 region and n-T-A-T-n-A-T-C in the -10 region with average 19 base pairs separating the two elements was predicted upstream of a number of heat-inducible genes.

Prostasin: a possible candidate gene for human hypertension

BACKGROUND

Prostasin, a serine protease, is suggested to be a novel mechanism regulating the epithelial sodium channel (ENaC) expressed in the distal nephron. This study aimed to evaluate whether the human prostasin gene is a novel candidate gene underlying blood pressure (BP) elevation.

METHODS

In a sample of healthy African-American (AA) and European-American (EA) twin subjects aged 17.6 +/- 3.3 years (n = 920, 45% AAs), race-specific tagging single-nucleotide polymorphisms (tSNPs) were identified to tag all the available SNPs +/- 2 kb up- and downstream of the prostasin gene from HapMap at r2 of 0.8-1.0. Selection yielded four tSNPs in AAs and one in EAs, with one tSNP (rs12597511: C to T) present in both AAs and EAs.

RESULTS

For rs12597511, CT and TT genotypes exhibited higher systolic BP (SBP) than CC genotype (115.9 +/- 1.1 mm Hg vs. 113.7 +/- 0.6 mm Hg, P = 0.025 (AAs); and 110.7 +/- 0.5 mm Hg vs. 109.6 +/- 0.6 mm Hg, P = 0.115 (EAs)). CT and TT genotypes compared with CC genotype showed a significant increase in diastolic BP (DBP) in both racial groups (62.5 +/- 0.7 mm Hg vs. 60.4 +/- 0.4 mm Hg, P = 0.003 (AAs); and 58.2 +/- 0.3 mm Hg vs. 56.7 +/- 0.4 mm Hg, P = 0.007 (EAs)). Furthermore, there was an increase in radial pulse wave velocity (PWV) in subjects with CT and TT genotype as compared with those with CC genotype (6.5 +/- 0.1 vs. 6.1 +/- 0.1 m/s, P < 0.0001) (EAs); and 6.7 +/- 0.1 vs. 6.6 +/- 0.1 m/s, P = 0.354 (AAs)). Analyses combining AAs and EAs consistently demonstrated a statistical significance of rs12597511 on all the phenotypes including SBP/DBP and PWV.

CONCLUSION

Genetic variation of the prostasin gene may be implicated in the development of hypertension in youths..

Is more aggressive lymph node assessment associated with improved survival in stage II-III colorectal cancer? Evidence from the Surveillance, Epidemiology and End Results (SEER) cancer registry

4048

Background: NCCN guidelines recommend assessment of =12 lymph nodes (LN) to improve accuracy in colorectal cancer (CRC) staging. Previous studies have used various cut-points to assess the relationship between the number of LN sampled and survival. The association between NCCN guideline-compliant nodal sampling and survival is assessed, while controlling for other risk factors. Methods: We selected 145,485 adult patients newly diagnosed with stage II or III from SEER during 1990–2003. Kaplan-Meier curves were compared using the log-rank test. Cox proportional hazards models were constructed to determine the effect of sampling ≥ 12 LN on survival. Results: Median patient follow-up was 5.7 years. The table shows overall survival rates in CRC patients with < 12 versus =12 LN assessed: After adjusting for age, sex, tumor size and grade, sampling ≥ 12 LN was independently associated with improved survival. For patients with =12 versus <12 LN assessed, survival increased by 13% for stage IIa [HR=0.75; 95%CI 0.72–0.78; p< .001], 16% for stage IIb [HR=0.69; 95%CI 0.67- 0.71; p< .001], 12% for stage IIIb [HR=0.75; 95%CI 0.72–0.77], and 10% for stage IIIc [HR=0.85, 95%CI 0.81–0.89]. The association was not statistically significant for stage IIIa patients. Conclusion: Consistent with previous reports, this analysis found that optimal nodal sampling increased survival across stage II and III, specifically when ≥ 12 LN are sampled and when controlling for other risk factors. Furthermore, the results underscore the need for adhering to the NCCN guidelines. The lack of a statistically significant association in stage IIIa patients may be due to small cohort size.

[Table: see text]

[Table: see text]

Evaluation of mechanical properties and biological response of an alumina-forming Ni-free ferritic alloy

PM 2000 is a Ni-free oxide dispersion strengthened Fe-20Cr-5Al alloy able to develop a fine, dense and tightly adherent alpha-alumina scale during high-temperature oxidation. Despite the high temperature involved during thermal oxidation (1100 degrees C), microstructural changes in the candidate material, a hot rolled product, hardly occurs. Consequently, the good mechanical properties of the as-received material are not significantly affected. Moreover, due to the high compressive residual stresses at the alumina scale, an increase in the fatigue limit from 500 to 530 MPa is observed. Such stresses also account for the high capability of the coating/metal system to withstand more than 1% tensile deformation without cracking. The biocompatibility of the alloy was assessed in comparison to commercial alumina. Saos-2 osteoblast-like cells were either challenged with PM 2000 particles, or seeded onto PM 2000 (with and without scale) solid samples. Viability, growth, and ALP release from cells were assessed after 3 or 7 days, while mineralization was checked at 18 days. This study has demonstrated that PM 2000 with and without scale are capable of supporting in vitro growth and function of osteoblast-like cells over a period of 18 days. Results from this study suggest that the resulting alumina/alloy system combines the good mechanical properties of the alloy with the superior biocompatibility of the alpha-alumina, for which there is very good clinical experience.

Relationship between the regulatory region polymorphism of human tissue kallikrein gene and essential hypertension

Ten alleles with length and nucleotide sequence variations were identified in the regulatory region of human tissue kallikrein gene. This present study aimed to study the polymorphisms of the regulatory region of human tissue kallikrein gene of the Chinese and investigate the relationship of the polymorphisms with essential hypertension. A case-control study was conducted in 200 hypertensive and 200 normotensive subjects of unrelated Chinese Han origin. All subjects were aged from 30 to 70 years and had no history of diabetes mellitus, kidney failure, or thyroid gland disease. The alleles were detected by polymerase chain reaction (PCR) and genotyping was performed with allele-specific oligonucleotide analysis (ASO). Data from the essential hypertensive and control subjects were statistically analysed by the Student's t-test and chi2-test. The age- and gender-matching of the groups were accurate. The case group and the control group were in Hardy-Weinberg equilibrium at this locus (cases, P=0.313; control subjects, P=0.457). There were nine alleles among the case and control groups, and the allele frequencies were found to be significantly different between cases and controls (chi2=25.701, P<0.001). The genotype frequencies were also significantly different (chi2=70.100, P<0.001) between these two groups. In conclusion, there are polymorphisms in the regulatory region of human tissue kallikrein gene in the Chinese Han people. Differences in both allele frequencies and genotype frequencies between these two groups have provided evidence towards the association of hypertension with the polymorphisms in this studied site.

Recombinant adeno-associated virus-mediated kallikrein gene therapy reduces hypertension and attenuates its cardiovascular injuries

Gene therapy of hypertension requires long-term expression of a therapeutic gene to achieve stable reduction of blood pressure. Human tissue kallikrein (HK) cleaves kininogen to produce a potent vasoactive peptide kinin, which plays an important role in the regulation of the cardiovascular and renal functions. In the present study, we have delivered human kallikrein cDNA with an rAAV vector to explore the potential therapeutic effects of kallikrein on hypertension and related secondary complications. A single tail vein injection of the rAAV-HK vector into the adult spontaneously hypertensive rats resulted in a significant reduction (12.0+/-2.55 mmHg, P<0.05, n=6, ANOVA) of the systolic blood pressure from 2 weeks after vector injection, when compared with the control rAAV-lacZ vector-injected rats. Weekly blood pressure monitoring showed stable hypertension-reduction effect throughout the course of the 20-week experiments. In addition, total urine microalbumin contents decreased as a result of rAAV-HK treatment. Histological analysis of various tissues showed remarkable amelioration of cardiovascular hypertrophy, renal injury and collagen depositions in the rAAV-treated group. Finally, persistent expression of the transgene product HK was confirmed by the enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction. We conclude that rAAV-mediated HK delivery rendered a long-term and stable reduction of hypertension and protected against renal injury, cardiac remodeling in the spontaneously hypertensive rat model. Further studies are warranted for the development of a gene therapy strategy for human hypertension.

Inducible, brain region-specific expression of a dominant negative mutant of c-Jun in transgenic mice decreases sensitivity to cocaine

Administration of cocaine induces the Fos family of transcription factors in the striatum, including the nucleus accumbens (NAc), a brain region important for the rewarding effects of addictive drugs. Several Fos proteins are induced acutely by cocaine, with stable isoforms of DeltaFosB predominating after chronic drug administration. However, it has been difficult to study the functional consequences of these Fos responses in vivo. Fos proteins heterodimerize with members of the Jun family to form active AP-1 transcription factor complexes. In the present study, we took advantage of this property and generated transgenic mice, using the tetracycline gene regulation system, that support the inducible, brain region-specific expression of a dominant negative mutant form of c-Jun (Deltac-Jun), which can antagonize the actions of Fos proteins. Expression of Deltac-Jun in the striatum and certain other brain regions of adult mice decreases their development of cocaine-induced conditioned place preference, suggesting reduced sensitivity to the rewarding effects of cocaine. In contrast, Deltac-Jun expression had no effect on cocaine-induced locomotor activity or sensitization. However, expression of Deltac-Jun in adult mice blocked the ability of chronic cocaine administration to induce three known targets for AP-1 in the NAc: the AMPA glutamate receptor subunit GluR2, the cyclin-dependent protein kinase Cdk5, and the transcription factor nuclear factor-kappaB (NFkappaB), without affecting several other proteins examined for comparison. Taken together, these results provide further support for an important role of AP-1-mediated transcription in some of the behavioral and molecular mechanisms underlying cocaine addiction.

Genetic targeting for cardiovascular therapeutics: are we near the summit or just beginning the climb?

This article is based on an Experimental Biology symposium held in April 2001 and presents the current status of gene therapy for cardiovascular diseases in experimental studies and clinical trials. Evidence for the use of gene therapy to limit neointimal hyperplasia and confer myocardial protection was presented, and it was found that augmenting local nitric oxide (NO) production using gene transfer (GT) of NO synthase or interruption of cell cycle progression through a genetic transfer of cell cycle regulatory genes limited vascular smooth muscle hyperplasia in animal models and infra-inguinal bypass patients. The results of application of vascular endothelial growth factor (VEGF) GT strategies for therapeutic angiogenesis in critical limb and myocardial ischemia in pilot clinical trials was reviewed. In addition, experimental evidence was presented that genetic manipulation of peptide systems (i.e., the renin-angiotensin II system and the kallikrein-kinin system) was effective in the treatment of systemic cardiovascular diseases such as hypertension, heart failure, and renal failure. Although, as of yet, there are no well controlled human trials proving the clinical benefits of gene therapy for cardiovascular diseases, the data presented here in animal models and in human subjects show that genetic targeting is a promising and encouraging modality, not only for the treatment and long-term control of cardiovascular diseases, but for their prevention as well.

Human adrenomedullin gene delivery protects against cardiovascular remodeling and renal injury

We investigated the potential roles of adrenomedullin (AM) in cardiovascular and renal function by somatic gene delivery. We showed that a single intravenous injection of the human AM gene under the control of cytomegalovirus promoter/enhancer induces a prolonged delay in blood pressure rise for several weeks in spontaneously hypertensive rats, Dahl salt-sensitive, DOCA-salt, and two-kidney one-clip hypertensive rats as compared to their respective controls injected with a reporter gene. Expression of the human AM transcript was identified in the heart, kidney, lung, liver and aorta of the rat after adenovirus-mediated AM gene delivery by RT-PCR followed by Southern blot analysis. Immunoreactive human AM levels were measured in rat plasma and urine following AM gene delivery. AM gene delivery induced significant reduction of left ventricular mass in these hypertensive animal models. It also reduces urinary protein excretion and increases glomerular filtration rate, renal blood flow and urinary cAMP levels. AM gene transfer attenuated cardiomyocyte diameter and interstitial fibrosis in the heart, and reduced glomerular sclerosis, tubular disruption, protein cast accumulation and renal cell proliferation in the kidney. In the rat model with myocardial ischemia/reperfusion injury, AM gene delivery significantly reduced myocardial infarction, apoptosis, and superoxide production. Furthermore, local AM gene delivery significantly inhibited arterial thickening, promoted re-endothelialization and increased vascular cGMP levels in rat artery after balloon angioplasty. Collectively, these results indicate that human AM gene delivery attenuates hypertension, myocardial infarction, renal injury and cardiovascular remodeling in animal models via cAMP and cGMP signaling pathways. These findings provide new insights into the role of AM in cardiovascular and renal function.

A synthetic tissue kallikrein inhibitor suppresses cancer cell invasiveness

Serine proteinases modulate the interaction of tumor cells with extracellular matrix components during extravasation and metastasis. The serine proteinase tissue kallikrein has been previously demonstrated in several human adenocarcinomas, and we presently report the localization of immunoreactive kallikrein and its mRNA in pancreatic adenocarcinoma. In addition, a synthetic peptide-based inhibitor specific for tissue kallikrein (FE999024) was used in our studies to explore a possible role for kallikrein in cancer cell invasiveness. Matrigel invasion assays were performed with a human breast-cancer cell line, MDA-MB-231, which expresses tissue kallikrein in culture. In the presence of FE999024 invasion through Matrigel was inhibited in a dose-dependent manner to a maximum of 39%. We also developed a novel ex vivo assay in which breast cancer cells are infused into the pulmonary circulation of artificially ventilated explanted rat lungs. At intervals up to 6 hours after infusion pulmonary invasion was quantified by bronchial alveolar lavage to recover human cancer cells from the airspace. Invading cells in the lung interstitium were also quantified after immunohistochemistry with a monoclonal antibody specific for human cytokeratin 18. The synthetic kallikrein inhibitor attenuates breast cancer cell invasion into the airspace by 33% when quantified by lavage recovery and up to 34% as quantified in the lung interstitium by cytokeratin 18 immunostaining. Our results indicate tissue kallikrein may participate in the invasion and metastasis of human adenocarcinomas. The newly developed explanted rodent lung assay should be useful for the study of cancer cells, neutrophils, or other extravasating cells.

Prostasin, a potential serum marker for ovarian cancer: identification through microarray technology

BACKGROUND

Screening biomarkers for ovarian cancer are needed because of its late stage at diagnosis and poor survival. We used microarray technology to identify overexpressed genes for secretory proteins as potential serum biomarkers and selected prostasin, a serine protease normally secreted by the prostate gland, for further study.

METHODS

RNA was isolated and pooled from three ovarian cancer cell lines and from three normal human ovarian surface epithelial (HOSE) cell lines. Complementary DNA generated from these pools was hybridized to a microarray slide, and genes overexpressed in the cancer cells were identified. Real-time quantitative polymerase chain reaction was used to examine prostasin gene expression in ovarian cancer and HOSE cell lines. Anti-prostasin antibodies were used to examine prostasin expression and to measure serum prostasin by an enzyme-linked immunosorbent assay in 64 case patients with ovarian cancer and in 137 control subjects. Previously determined levels of CA 125, an ovarian cancer marker, were available from about 70% of all subjects. All statistical tests were two-sided.

RESULTS

Prostasin was detected by immunostaining more strongly in cancerous ovarian epithelial cells and stroma than in normal ovarian tissue. The mean level of serum prostasin was 13.7 microg/mL (95% confidence interval [CI] = 10.5 to 16.9 microg/mL) in 64 case patients with ovarian cancer and 7.5 microg/mL (95% CI = 6.6 to 8.3 microg/mL) in 137 control subjects (P<.001, after adjustment for the subject's age, year of collection, and specimen quality). In 14 of 16 case patients with both preoperative and postoperative serum samples, postoperative prostasin levels were statistically significantly lower than preoperative levels (P =.004). In 37 case patients with nonmucinous ovarian cancer and in 100 control subjects for whom levels of CA 125 and prostasin were available, the combination of markers gave a sensitivity of 92% (95% CI = 78.1% to 98.3%) and a specificity of 94% (95% CI = 87.4% to 97.7%) for detecting ovarian cancer.

CONCLUSIONS

Prostasin is overexpressed in epithelial ovarian cancer and should be investigated further as a screening or tumor marker, alone and in combination with CA 125.

Pindolol potentiation of paroxetine for generalized social phobia: a double-blind, placebo-controlled, crossover study

OBJECTIVE

The effectiveness of pindolol as an adjunctive treatment to boost response to selective serotonin reuptake inhibitors (SSRIs) in patients with generalized social phobia was tested.

METHOD

A double-blind, placebo-controlled, crossover design was used to compare addition of 5 mg of pindolol t.i.d. or placebo for 4 weeks to a steady paroxetine dose. Subjects were 14 patients with generalized social phobia who were less than "very much improved" on the Clinical Global Impression scale after at least 10 weeks of treatment with a maximally tolerated dose of paroxetine. Changes on the Liebowitz Social Anxiety Scale and the Social Phobia Inventory scores were compared across the two crossover periods.

RESULTS

Pindolol was not significantly superior to placebo for augmenting the effects of paroxetine on social anxiety symptoms. None of the 14 subjects was deemed a responder to the pindolol arm of the crossover.

CONCLUSIONS

Pindolol was no more effective than placebo in augmenting the effects of SSRI treatment for generalized social phobia.

Rescue of impaired angiogenesis in spontaneously hypertensive rats by intramuscular human tissue kallikrein gene transfer

Angiogenesis represents a compensatory response targeted to preserve the integrity of tissues subjected to ischemia. The aim of the present study was to examine whether reparative angiogenesis is impaired in spontaneously hypertensive rats (SHR), as a function of progression of hypertension. In addition, the potential of gene therapy with human tissue kallikrein (HK) in revascularization was challenged in SHR and normotensive Wistar-Kyoto rats (WKY) that underwent excision of the left femoral artery. Expression of vascular endothelial growth factor and HK was upregulated in ischemic hindlimb of WKY but not of SHR. Capillary density was increased in ischemic adductor muscle of WKY (from 266+/-20 to 633+/-73 capillaries/mm(2) at 28 days, P<0.001), whereas it remained unchanged in SHR (from 276+/-20 to 354+/-48 capillaries/mm(2), P=NS), thus compromising perfusion recovery as indicated by reduced plantar blood flow ratio (0.61+/-0.08 versus 0.92+/-0.07 in WKY at 28 days, P<0.05). In separate experiments, saline or 5x10(9) pfu adenovirus containing the HK gene (Ad.CMV-cHK) or the beta-galactosidase gene (Ad.CMV-LacZ) was injected intramuscularly at 7 days after the induction of ischemia. Ad.CMV-cHK augmented capillary density and accelerated hemodynamic recovery in both strains, but these effects were more pronounced in SHR (P<0.01). Our results indicate that native angiogenic response to ischemia is impaired in SHR, possibly as a result of defective modulation of endothelial cell mitogens. Supplementation with kallikrein, one of the growth factors found to be deficient in SHR, restores physiological angiogenic response utilitarian for tissue healing. Our discoveries may have important implications in vascular medicine for therapeutic benefit.

A surface modified ODS superalloy by thermal oxidation for potential implant applications

In the present work attention is paid on the composition, structure and protective properties of alumina layer produced by high temperature oxidation on MA 956 superalloy (Fe-20Cr-4.5Al-0.5Ti-0.5Y(2)O(3) (wt %)). The combination of good mechanical properties of this material and the excellent biocompatibility, the good wear and corrosion behavior of an outer alpha-alumina layer, limiting the release of ionic species and wear debris from the bulk material into the body-fluid environment, can make this material a candidate alloy for medical applications. Isothermal oxidation at 1100 degrees C in air of the alloy has led to the formation of a fine-grained, compact and adherent alpha-alumina scale. Oxide nodules rich in Ti, Y, Cr, and Fe were found on the top of the surface. In vitro electrochemical corrosion experiments showed good protective properties of the oxide scale. Moreover, no spallation of the alumina layer was observed. This feature is significant considering that the alumina layer has to withstand very high compressive stresses resulting from both growth and thermal stresses incorporated during cooling.

Prostasin is a glycosylphosphatidylinositol-anchored active serine protease

A recombinant human prostasin serine protease was expressed in several human cell lines. Subcellular fractionation showed that this serine protease is synthesized as a membrane-bound protein while a free-form prostasin is secreted into the culture medium. Prostasin was identified in nuclear and membrane fractions. Membrane-bound prostasin can be released by phosphatidylinositol-specific phospholipase C treatment, or labeled by [(3)H]ethanolamine, indicating a glycosylphosphatidylinositol anchorage. A prostasin-binding protein was identified in mouse and human seminal vesicle fluid. Both the secreted and the membrane-bound prostasin were able to form a covalently linked 82-kDa complex when incubated with seminal vesicle fluid. The complex formation between prostasin and the prostasin-binding protein was inhibited by a prostasin antibody, heparin, and serine protease inhibitors. Prostasin's serine protease activity was inhibited when bound to the prostasin-binding protein in mouse seminal vesicle fluid. This study indicates that prostasin is an active serine protease in its membrane-bound form.

Adrenomedullin gene delivery attenuates renal damage and cardiac hypertrophy in Goldblatt hypertensive rats

Adrenomedullin (AM) is a potent vasodilator and natriuretic peptide that plays an important role in cardiovascular function. In this study, we employed a somatic gene delivery approach to explore its potential protective role in renovascular hypertension. A single tail vein injection of adenovirus harboring the human AM gene significantly blunted a blood pressure increase that lasted for more than 3 wk in two-kidney one-clip (2K1C) hypertensive rats. The expression of human AM mRNA was detected in the kidney, adrenal gland, heart, lung, and liver, and immunoreactive human AM was detected in the plasma and urine of 2K1C rats after human AM gene delivery. A maximal blood pressure difference of 28 mmHg was observed 10 days after AM gene delivery, compared with that in rats injected with the control virus carrying the LacZ gene. Human AM gene delivery significantly attenuated increases in the ratio of left ventricular weight to heart weight, cardiomyocyte diameter, and fibrosis in the heart, as well as glomerular sclerosis, tubular injuries, and protein casts in the kidney. The beneficial effects of AM gene delivery were accompanied by increased urinary cAMP levels, indicating activation of AM receptors. These findings provide new insights into the role of AM in renovascular hypertension and may have significance in therapeutic applications in cardiovascular diseases.

Initiation of nonselective alpha1-antagonist therapy and occurrence of hypotension-related adverse events among men with benign prostatic hyperplasia: a retrospective cohort study

BACKGROUND

Treatment of benign prostatic hyperplasia (BPH) with nonselective alpha1 antagonists such as terazosin, doxazosin, and prazosin results in blood pressure reduction due to vasodilation.

OBJECTIVE

Using claims data from a large Medigap plan, we examined the effect of initiating nonselective alpha1-antagonist therapy on the incidence of hypotension-related adverse events likely to be associated with vascular alpha-adrenoreceptor antagonism in patients with BPH.

METHODS

Medical and prescription claims data were obtained from the MEDSTAT Group for 53,824 men with a diagnosis code for BPH during the study period (January 1995-December 1997). We examined the rate of possible hypotension-related adverse events (diagnosis codes for hypotension, syncope, dizziness, fractures, and other injuries) per 10,000 person-days for men who began therapy with alpha1 antagonists and for a random sample of nonusers, stratified by prior use of other antihypertensive agents.

RESULTS

After adjusting for baseline differences in event rates, those who initiated alpha1-antagonist therapy (n = 1564) had a significantly greater increase in hypotension-related adverse-event rates in the 4 months after initiation (vs the 4 months before initiation) than randomly selected nonusers (n = 8641) (increase of 1.82 vs decrease of 0.02 events per 10,000 person-days among those not taking antihypertensive agents; increase of 0.94 vs 0.69 events per 10,000 person-days among those taking other antihypertensive agents; P < 0.01). This increase began earlier and lasted longer among patients taking other antihypertensive agents. Those who discontinued their alpha1 antagonist had a higher rate of hypotensive events at baseline than those who did not (5.09 vs 3.19 events per 10,000 person-days among those using other antihypertensive agents; 3.62 vs 2.27 events per 10,000 person-days among those not using other antihypertensive agents; P < 0.05).

CONCLUSIONS

Initiation of nonselective alpha1-antagonist therapy for the treatment of BPH increases the risk of a cluster of clinical events consistent with vascular alpha-adrenoreceptor antagonism. This effect is seen during a 4-month period around the initiation date. Prior initiation of other antihypertensive medication increases this effect. Urologists should consult with a patient's primary care physician about use of other antihypertensive agents before initiating nonselective alpha1-antagonist therapy for BPH.

Identification of a major heparin-binding site in kallistatin

Kallistatin is a heparin-binding serine proteinase inhibitor (serpin), which specifically inhibits human tissue kallikrein by forming a covalent complex. The inhibitory activity of kallistatin is blocked upon its binding to heparin. In this study we attempted to locate the heparin-binding site of kallistatin using synthetic peptides derived from its surface regions and by site-directed mutagenesis of basic residues in these surface regions. Two synthetic peptides, containing clusters of positive-charged residues, one derived from the F helix and the other from the region encompassing the H helix and C2 sheet of kallistatin, were used to assess their heparin binding activity. Competition assay analysis showed that the peptide derived from the H helix and C2 sheet displayed higher and specific heparin binding activity. The basic residues in both regions were substituted to generate three kallistatin double mutants K187A/K188A (mutations in the F helix) and K307A/R308A and K312A/K313A (mutations in the region between the H helix and C2 sheet), using a kallistatin P1Arg variant as a scaffold. Analysis of these mutants by heparin-affinity chromatography showed that the heparin binding capacity of the variant K187A/K188A was not altered, whereas the binding capacity of K307A/R308A and K312A/K313A mutants was markedly reduced. Titration analysis with heparin showed that the K312A/K313A mutant has the highest dissociation constant. Like kallistatin, the binding activity of K187A/K188A to tissue kallikrein was blocked by heparin, whereas K307A/R308A and K312A/K313A retained significant binding and inhibitory activities in the presence of heparin. These results indicate that the basic residues, particularly Lys(312)-Lys(313), in the region between the H helix and C2 sheet of kallistatin, comprise a major heparin-binding site responsible for its heparin-suppressed tissue kallikrein binding.

Local delivery of human tissue kallikrein gene accelerates spontaneous angiogenesis in mouse model of hindlimb ischemia

BACKGROUND

Human tissue kallikrein (HK) releases kinins from kininogen. We investigated whether adenovirus-mediated HK gene delivery is angiogenic in the context of ischemia.

METHODS AND RESULTS

Hindlimb ischemia, caused by femoral artery excision, increased muscular capillary density (P:<0.001) and induced the expression of kinin B(1) receptor gene (P:<0.05). Pharmacological blockade of B(1) receptors blunted ischemia-induced angiogenesis (P:<0.01), whereas kinin B(2) receptor antagonism was ineffective. Intramuscular delivery of adenovirus containing the HK gene (Ad. CMV-cHK) enhanced the increase in capillary density caused by ischemia (969+/-32 versus 541+/-18 capillaries/mm(2) for control, P:<0.001), accelerated blood flow recovery (P:<0.01), and preserved energetic charge of ischemic muscle (P:<0.01). Chronic blockade of kinin B(1) or B(2) receptors prevented HK-induced angiogenesis.

CONCLUSIONS

HK gene delivery enhances the native angiogenic response to ischemia. Angiogenesis gene therapy with HK might be applicable to peripheral occlusive vascular disease.

Novel roles of kallistatin, a specific tissue kallikrein inhibitor, in vascular remodeling

We have purified, cloned and characterized kallistatin, a tissue kallikrein-binding protein (KBP) in humans and rodents. Kallistatin is a unique serine proteinase inhibitor (serpin) with Phe-Phe residues at the P2 and P1 positions. Structural and functional analysis of kallistatin by site-directed mutagenesis and protein engineering indicate that wild-type kallistatin is selective for tissue kallikrein. Kallistatin is expressed and localized in endothelial and smooth muscle cells of blood vessels and has multiple roles in vascular function independent of the tissue kallikrein-kinin system. First, kallistatin induces vasorelaxation of isolated aortic rings and reduces renal perfusion pressure in isolated rat kidneys. Transgenic mice overexpressing rat kallistatin are hypotensive, and adenovirus-mediated gene delivery of human kallistatin attenuates blood pressure rise in spontaneously hypertensive rats. Second, kallistatin stimulates the proliferation and migration of vascular smooth muscle cells in vitro and neointima formation in balloon-injured rat arteries. Third, kallistatin inhibits the proliferation, migration and adhesion of endothelial cells in vitro and angiogenesis in the rat model of hindlimb ischemia. These results demonstrate novel roles of kallistatin in blood pressure regulation and vascular remodeling.

A positively charged loop on the surface of kallistatin functions to enhance tissue kallikrein inhibition by acting as a secondary binding site for kallikrein

Kallistatin is a serine proteinase inhibitor (serpin) that specifically inhibits tissue kallikrein. The inhibitory activity of kallistatin is abolished upon heparin binding. The loop between the H helix and C2 sheet of kallistatin containing clusters of basic amino acid residues has been identified as a heparin-binding site. In this study, we investigated the role of the basic residues in this region in tissue kallikrein inhibition. Kallistatin mutants containing double Ala substitutions for these basic residues displayed a 70-80% reduction of association rate constants, indicating the importance of these basic residues in tissue kallikrein inhibition. A synthetic peptide derived from the sequence between the H helix and C2 sheet of kallistatin was shown to suppress the kallistatin-kallikrein interaction through competition for tissue kallikrein binding. To further evaluate the function of this loop, we used alpha1-antitrypsin, a non-heparin-binding serpin and slow tissue kallikrein inhibitor as a scaffold to engineer kallikrein inhibitors. An alpha1-antitrypsin chimera harboring the P3-P2' residues and a sequence homologous to the positively charged region between the H helix and C2 sheet of kallistatin acquired heparin-suppressed inhibitory activity toward tissue kallikrein and exhibited an inhibitory activity 20-fold higher than that of the other chimera, which contained only kallistatin's P3-P2' sequence, and 2300-fold higher than that of wild-type alpha1-antitrypsin. The alpha1-antitrypsin chimera with inhibitory characteristics similar to those of kallistatin demonstrates that the loop between the H helix and C2 sheet of kallistatin is crucial in tissue kallikrein inhibition, and this functional loop can be used as a module to enhance the inhibitory activity of a serpin toward tissue kallikrein. In conclusion, our results indicate that a positively charged loop between the H helix and C2 sheet of a serpin can accelerate the association of a serpin with tissue kallikrein by acting as a secondary binding site.

Roles of the P1, P2, and P3 residues in determining inhibitory specificity of kallistatin toward human tissue kallikrein

Kallistatin is a serpin with a unique P1 Phe, which confers an excellent inhibitory specificity toward tissue kallikrein. In this study, we investigated the P3-P2-P1 residues (residues 386-388) of human kallistatin in determining inhibitory specificity toward human tissue kallikrein by site-directed mutagenesis and molecular modeling. Human kallistatin mutants with 19 different amino acid substitutions at each P1, P2, or P3 residue were created and purified to compare their kallikrein binding activity. Complex formation assay showed that P1 Arg, P1 Phe (wild type), P1 Lys, P1 Tyr, P1 Met, and P1 Leu display significant binding activity with tissue kallikrein among the P1 variants. Kinetic analysis showed the inhibitory activities of the P1 mutants toward tissue kallikrein in the order of P1 Arg > P1 Phe > P1 Lys >/= P1 Tyr > P1 Leu >/= P1 Met. P1 Phe displays a better selectivity for human tissue kallikrein than P1 Arg, since P1 Arg also inhibits several other serine proteinases. Heparin distinguishes the inhibitory specificity of kallistatin toward kallikrein versus chymotrypsin. For the P2 and P3 variants, the mutants with hydrophobic and bulky amino acids at P2 and basic amino acids at P3 display better binding activity with tissue kallikrein. The inhibitory activities of these mutants toward tissue kallikrein are in the order of P2 Phe (wild type) > P2 Leu > P2 Trp > P2 Met and P3 Arg > P3 Lys (wild type). Molecular modeling of the reactive center loop of kallistatin bound to the reactive crevice of tissue kallikrein indicated that the P2 residue required a long and bulky hydrophobic side chain to reach and fill the hydrophobic S2 cleft generated by Tyr(99) and Trp(219) of tissue kallikrein. Basic amino acids at P3 could stabilize complex formation by forming electrostatic interaction with Asp(98J) and hydrogen bond with Gln(174) of tissue kallikrein. Our results indicate that tissue kallikrein is a specific target proteinase for kallistatin.

Adrenomedullin gene delivery attenuates hypertension, cardiac remodeling, and renal injury in deoxycorticosterone acetate-salt hypertensive rats

Adrenomedullin (AM) is a potent vasodilator and natriuretic peptide that plays an important role in cardiorenal function. In this study, we explored the potential protective role of AM in volume-dependent hypertension by somatic gene delivery. Adenovirus containing the human AM cDNA under the control of the cytomegalovirus promoter/enhancer was administered into deoxycorticosterone acetate (DOCA)-salt hypertensive rats via tail vein injection. A single injection of the human AM gene resulted in a prolonged reduction of blood pressure with a maximal reduction of 41 mm Hg 9 days after gene delivery. Human AM gene delivery enhanced renal function, as indicated by a 3-fold increase in renal blood flow and a 2-fold increase in glomerular filtration rate (n=5, P<0.05). Histological examination of the kidney revealed a significant reduction in glomerular sclerosis, tubular injury, luminol protein cast accumulation, and interstitial fibrosis as well as urinary protein. Human AM gene delivery caused significant decreases in left ventricular weight and cardiomyocyte diameter, which were accompanied by reduced interstitial fibrosis and extracellular matrix formation within the heart. Expression of human AM mRNA was detected in the kidney, adrenal gland, heart, aorta, lung, and liver; immunoreactive human AM levels were measured in urine and plasma. Significant increases in urinary and cardiac cAMP levels were observed in DOCA-salt rats receiving the human AM gene, indicating activation of the AM receptor. These findings showed that AM gene delivery attenuates hypertension, protects against cardiac remodeling and renal damage in volume-overload hypertension, and may have significance in therapeutic applications in cardiovascular and renal diseases.

Adenovirus-mediated human tissue kallikrein gene delivery induces angiogenesis in normoperfused skeletal muscle

We investigated whether local delivery of the tissue kallikrein gene induces angiogenesis in normoperfused mouse hindlimb muscles. Intramuscular injection of adenovirus containing the human tissue kallikrein gene under the control of a cytomegalovirus enhancer/promoter sequence resulted in local production and release of recombinant human tissue kallikrein, whereas transgene expression was absent in muscles of the contralateral hindlimb. Angiogenesis in infected muscles was documented by histological evidence of increased capillary density. In contrast, no angiogenic effect was seen either in the ipsilateral gastrocnemius or contralateral hindlimb muscles. Neovascularization was associated with a transient increase in muscular blood flow as determined by laser Doppler flowmetry. We also investigated the mechanisms of kallikrein-induced angiogenesis. We found that the angiogenic response to kallikrein was abolished by chronic blockade of the kinin B(1) or B(2) receptor or by inhibition of nitric oxide synthase. In addition, inhibition of cyclooxygenase-2 by nimesulide significantly reduced kallikrein-induced effects. These results indicate that (1) human tissue kallikrein acts as an angiogenic factor in normoperfused skeletal muscle and (2) nitric oxide and prostacyclin are essential mediators of kallikrein-induced angiogenesis. Our findings provide new insights into the role of the tissue kallikrein-kinin system in vascular biology.

Reduced cardiac hypertrophy and altered blood pressure control in transgenic rats with the human tissue kallikrein gene

To evaluate the cardiovascular actions of kinins, we established a transgenic rat line harboring the human tissue kallikrein gene, TGR(hKLK1). Under the control of the zinc-inducible metallothionein promoter, the transgene was expressed in most tissues including the heart, kidney, lung, and brain, and human kallikrein was detected in the urine of transgenic animals. Transgenic rats had a lower 24-h mean arterial pressure in comparison with control rats, which was further decreased when their diet was supplemented with zinc. The day/night rhythm of blood pressure was significantly diminished in TGR(hKLK1) animals, whereas the circadian rhythms of heart rate and locomotor activity were unaffected. Induction of cardiac hypertrophy by isoproterenol treatment revealed a marked protective effect of the kallikrein transgene because the cardiac weight of TGR(hKLK1) increased significantly less, and the expression of atrial natriuretic peptide and collagen III as markers for hypertrophy and fibrosis, respectively, were less enhanced. The specific kinin-B2 receptor antagonist, icatibant, abolished this cardioprotective effect. In conclusion, the kallikrein-kinin system is an important determinant in the regulation of blood pressure and its circadian rhythmicity. It also exerts antihypertrophic and antifibrotic actions in the heart.

Bradykinin B(1) receptor mediates inhibition of neointima formation in rat artery after balloon angioplasty

We evaluated the effects of the kallikrein-kinin system on the proliferation and migration of primary cultured vascular smooth muscle cells (VSMCs) in vitro and neointima formation in balloon-injured rat carotid arteries in vivo. In cultured rat VSMCs, tissue kallikrein inhibited cell proliferation, and this inhibitory effect was blocked by Sar-Tyr-Aca(epsilon)-Lys [D-betaNal(7), Ile(8)]-des-Arg(9)-bradykinin, a bradykinin B(1) receptor antagonist, and by icatibant, a bradykinin B(2) receptor antagonist. Platelet-derived growth factor significantly increased the expression of the B(1) receptor but not the B(2) receptor in VSMCs. Platelet-derived growth factor-induced cell migration was significantly attenuated by des-Arg(9)-bradykinin and to a lesser degree by bradykinin. Endogenous B(1) receptor mRNA increased in rat carotid arteries after balloon angioplasty. After local delivery of adenovirus carrying the human tissue kallikrein gene into the rat carotid artery, we observed a 54% reduction in the intima/media ratio at the injured site compared with the control ratio (n=7, P:<0.01). Administration of the B(1) receptor antagonist via minipumps blocked the protective effect of kallikrein and partially reversed the intima/media ratio toward the control ratio. Kallikrein gene delivery results in the regeneration of endothelium compared with the control groups, and the B(1) receptor antagonist abolished this effect. Nitrite/nitrate, cGMP, and cAMP levels in balloon-injured arteries significantly increased after kallikrein gene delivery, whereas the B(1) receptor antagonist abolished these increases (n=4 or 5, P:<0.05). These results indicate that the B(1) receptor contributes to the reduction of neointima formation via the promotion of reendothelialization and inhibition of VSMC proliferation and migration through NO-cGMP and cAMP signaling pathways. This study provides significant implications in treating restenosis after revascularization.

Human adrenomedullin gene delivery protects against cardiac hypertrophy, fibrosis, and renal damage in hypertensive dahl salt-sensitive rats

Adrenomedullin (AM) is a potent vasodilator expressed in tissues relevant to cardiac and renal functions. Our previous study showed that delivery of the human AM gene in the form of naked DNA caused a prolonged reduction of blood pressure in genetically hypertensive rats. In this study, we evaluated potential protective effects of adenovirus-mediated AM gene delivery on salt-induced cardiorenal lesions in hypertensive Dahl saltsensitive (DSS) rats. Adenovirus carrying the human AM cDNA under the control of the cytomegalovirus promoter-enhancer (Ad.CMV-hAM) was generated by homologous recombination of E. coli. Expression of recombinant human AM was detected by a radioimmunoassay in the medium of human embryonic kidney 293 cells transfected with Ad.CMV-hAM. A single intravenous injection of Ad.CMV-hAM caused a significant reduction of systolic blood pressure for 4 weeks in DSS rats compared with control rats with or without injection of adenovirus carrying the green fluorescent protein gene. AM gene delivery significantly reduced left ventricular mass and urinary protein, increased cAMP levels, and enhanced renal function as evidenced by increases in glomerular filtration rate and renal blood flow. Morphological investigations showed that AM gene transfer reduced cardiomyocyte diameter and interstitial fibrosis in the heart as well as glomerular sclerosis, tubular disruption, and protein cast accumulation in the kidney. Expression of human AM mRNA was identified in rat heart, kidney, lung, liver, and aorta, and immunoreactive human AM levels were measured in rat plasma and urine. These results indicate that human AM gene delivery protects against salt-induced hypertension and cardiac and renal lesions in DSS rats via activation of cAMP as a second messenger. These findings provide new insights into the role of AM in salt-induced hypertension and may have implications in therapeutic applications to salt-related cardiovascular and renal diseases.

Human tissue kallikrein gene delivery attenuates hypertension, renal injury, and cardiac remodeling in chronic renal failure

BACKGROUND

Tissue kallikrein cleaves kininogen substrate to produce the potent vasodilating peptide kinin, which plays important roles in cardiovascular and renal function. To explore cardiac and renal potential protective effects of kallikrein gene delivery in chronic renal failure, we delivered adenovirus carrying the human tissue kallikrein cDNA (cHK) into rats with 5/6 reduction of renal mass.

METHODS

Expression of human tissue kallikrein in rats was assessed by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR)/Southern blotting. Physiological parameters monitored in rats included systolic blood pressure, heart rate, and urinary excretion of protein, albumin, kinin, cGMP, cAMP, and nitrate/nitrites. Systemic and regional hemodynamics were measured by fluorescent-labeled microspheres. Heart weight and myocyte diameter were used to assess left ventricular hypertrophy. Quantitative and qualitative morphological analyses were used to evaluate histologic changes in kidney and heart sections.

RESULTS

Active tissue kallikrein reached a peak serum level of 463 +/- 76 ng/mL following gene delivery and returned to control levels within 21 days. A maximal blood pressure reduction of 37 mm Hg was observed within one week in rats receiving kallikrein gene delivery as compared with control rats receiving adenovirus containing the luciferase gene (159 +/- 5 vs. 196 +/- 6 mm Hg, N = 15, P < 0.001), and a significant blood pressure difference continued for five weeks postgene delivery. Kallikrein gene delivery significantly decreased total urinary protein and albumin excretion and increased levels of urinary kinin, nitrite/nitrate, and cGMP levels. Cardiac output and regional blood flow were also increased, while peripheral vascular resistance decreased. Kallikrein gene transfer reduced glomerular sclerotic lesions, tubular damage, lumenal protein cast accumulation, and interstitial inflammation in the kidney. Myocardial hypertrophy and fibrosis were also attenuated in rats receiving kallikrein gene delivery.

CONCLUSIONS

These findings indicated that kallikrein gene delivery attenuates hypertension and protects against renal injury and cardiac remodeling in the rat remnant kidney model of chronic renal failure.