Istvan Kovanecz | Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (original) (raw)

Papers by Istvan Kovanecz

PubMed, 1995

We studied the level of the cytotoxic anti-HLA antibodies (CTA) in 90 hemodialyzed chronic uraemi... more We studied the level of the cytotoxic anti-HLA antibodies (CTA) in 90 hemodialyzed chronic uraemic patients who were on waiting list of transplantation. An association between alleles of HLA A1, B8, DR3 haplotype and the level of CTA was studied. The ratio of the reduced CTA producing subjects was significantly higher in the HLA B8 and DR3 carriers. We could observe the highest ratio in the joint appearance of these alleles. In the presence of HLA A1 allele the ratio was decreased beside B8 or DR3 even as joined attendance of these alleles. Our data suggest a different role of these linked antigens in the regulation of cytotoxic antibody production.

PubMed, 1996

In the present study we tested the preconditioning effect of repeated beta adrenergic stress indu... more In the present study we tested the preconditioning effect of repeated beta adrenergic stress induced by Isoproterenol in chronically instrumented, conscious rabbits. We have found that at least 5 intravenous administrations of Isoproterenol, repeated at 10 min intervals, were necessary to induce a long-term cardiac adaptation manifested by a significant reduction of the harmful ischaemic changes due to cardiac stress 24 and 48 hours after preconditioning. These results suggest that a well-defined threshold level of the preconditioning stress is needed to trigger induction of metabolic changes leading to development of delayed and long-term cardiac adaptation.

The Journal of Sexual Medicine, May 11, 2022

The Journal of Urology, Apr 1, 2007

The Journal of Sexual Medicine, 2019

condition at the 2 mg/kg dose (WD+2mg/kgRap: 9.18±1.5 ICP area/MAP; p<0.01), but failed to signif... more condition at the 2 mg/kg dose (WD+2mg/kgRap: 9.18±1.5 ICP area/MAP; p<0.01), but failed to significantly augment erectile function at the 1 mg/kg dose (WD+1mg/kgRap: 6.73±1.0 ICP area/MAP; p¼0.10). Penile production of the ROS hydrogen peroxide and superoxide were elevated in vehicle treated WD-fed mice (CD+Veh: 0.85±0.06 mM vs. WD+Veh: 1.35±0.14 mM; p<0.01), which was normalized in WD-fed mice with 2 mg/kg Rap treatment (1.03±0.05 mM; p¼0.04 vs. WD+Veh). Similarly, Nox-mediated penile ROS was elevated in vehicle treated WD-fed mice (CD+Veh: 0.26±0.04 mM vs. WD+Veh: 0.73±0.15 mM; p<0.01), which was normalized in WD-fed mice with 2 mg/kg Rap treatment (0.41±0.03 mM; p¼0.03 vs. WD+Veh). Conclusions: mTOR appears to be an upstream mediator of Nox activity in the penis following chronic WD consumption, which has a deleterious effect on erectile function. Molecular work will be needed to confirm these pharmacologic/physiological assessments. Disclosure: Work supported by industry: no.

International Journal of Impotence Research, May 25, 2017

Myostatin is present in striated myofibers but, except for myometrial cells, has not been reporte... more Myostatin is present in striated myofibers but, except for myometrial cells, has not been reported within smooth muscle cells (SMC). We investigated in the rat whether myostatin is present in SMC within the penis and the vascular wall and, if so, whether it is transcriptionally expressed and associated with the loss of corporal SMC occurring in certain forms of erectile dysfunction (ED). Myostatin protein was detected by immunohistochemistry/fluorescence and western blots in the perineal striated muscles, and also in the SMC of the penile corpora, arteries and veins, and aorta. Myostatin was found in corporal SMC cultures, and its transcriptional expression (and its receptor) was shown there by DNA microarrays. Myostatin protein was measured by western blots in the penile shaft of rats subjected to bilateral cavernosal nerve resection (BCNR), that were left untreated, or treated (45 days) with muscle-derived stem cells (MDSC), or concurrent daily low-dose sildenafil. Myostatin was not increased by BCNR (compared with sham operated animals), but over expressed after treatment with MDSC. This was reduced by concurrent sildenafil. The presence of myostatin in corporal and vascular SMC, and its overexpression in the corpora by MDSC therapy, may have relevance for the stem cell treatment of corporal fibrosis and ED.

The Journal of Urology, Apr 1, 2005

THE JOURNAL OF UROLOGY® cavernosal smooth muscle cells (CSMC) and fibroblasts of the tunica albug... more THE JOURNAL OF UROLOGY® cavernosal smooth muscle cells (CSMC) and fibroblasts of the tunica albuginea (TAP) when they are subjected to long-term incubation with increasing concentrations of tadalafil. METHODS: CSMC and TAP cultured from patients undergoing penile prosthetic implantation were characterized by immunocytochemistry for markers of SMC (a-smooth muscle actin (ASMA), smoothelin, and SM22), fibroblasts (vimentin), and myofibroblasts (ASMA and vimentin). Western blot analysis and RT/PCR were also carried out for these markers. Both cultures were then incubated with increasing concentrations of tadalafil (0, 0.1, 0.5, and 5 uM) for 14 days, and PDE5 was estimated by immunocytochemistry combined with quantitative image analysis (QIA), or for 7, 10, and 14 days with 0, 0.02, 0.1, 0.5, 1, and 5 uM) and assessed by quantitative western blot, and (at 14 days only) RT/real time PCR. Incubation ofCSMC and TAP was repeated for 14 days only, and at day 13,50 uM SNAP was added as NO donor, and cGMP levels in cell homogenates were measured 1 day later with an enzyme-immunoassay kit. A construct of the human PDE5 promoter (nt 3114 to 3711) expressing luciferase was cloned for nucleoporation into CSMC and determination of cGMP effects on luciferase expression by luminometry. RESULTS: CSMC and TAP were pure smooth muscle and fibroblast cultures, respectively, as assessed by the corresponding markers. Incubation of CSMC with tadalafil at 7,10 and 14 days did not up-regulate PDE-5 protein as assessed by immunocytochemistry. The western blot values paralleled what was seen by immunocytochemistry. In the presence of SNAP, the stimulation of cGMP production by tadalafil in CSMC and TAP was not impaired by a prior 14 days continuous incubation with tadalafil up to 0.2 uM. CONCLUSIONS: Long-term incubation of human penile CSMC and TAP with tadalafil at concentrations well above the in vitro IC-50 and around the in vivo Cmax for clinical use, did not up-regulate PDE5 expression nor decrease cGMP levels, suggesting that tachyphylaxis should not occur in vivo, at least through transcriptional activation.

The Journal of Sexual Medicine, 2017

The Journal of Urology, Apr 1, 2010

ABSTRACT INTRODUCTION AND OBJECTIVES: We have previously demonstrated that long term treatment wi... more ABSTRACT INTRODUCTION AND OBJECTIVES: We have previously demonstrated that long term treatment with PDE 5 inhibitors preserves corporal smooth muscle and ameliorates fibrotic degeneration normally seen after bilateral cavernosal nerve resection (BCNR) in rats. However, the mechanism by which these drugs promote corporal protection remains poorly understood. We aim to determine the gene expression profile of penile tissue after BCNR and the subsequent treatment with sildenafil in relation to angiogenesis related-pathways. METHODS: Fisher rats were subjected to BCNR or sham operation and treated with or without sildenafil (20 mg/Kg. B.W drinking water) for 3 days (short term treatment) or for 45 days (long term treatment). RNA isolated from the penile shaft was subjected real time PCR array with the RAT- angiogenesis array, which comprises genes involved in angiogenic, fibrotic and antifibrotic pathways. We considered as significant those genes that demonstrated a � 2.0 fold change with its respective controls. Selected genes were corroborated by western blot analysis. RESULTS: Array data analysis from the comparison of sham versus BCNR for the short term treatment, revealed a decreased expression of 20 genes related to angiogenesis and tissue growth factors such as epiregulin (EREG:-2.82), metalloproteinase 3 (MMP3:-2.43), metalloproteinase 9 (MMP9: -7.49); platelet derived growth factor (PDGF:-2.43) and endothelial cell growth factor (ECGF:-2.27) among others, and an up-regulation of pro-fibrotic and antiangiogenic genes such as connective tissue growth factor (CTGF:3.35) and Maspin (Serpin b5: 2.77). The short term treatment with sildenafil reversed this process by up-regulating 22 genes such as EREG: 2.01, MMP 9: 3.51 among others and down regulation of CTFG:-2.01 and TGF�: -2.00. A similar response but with more pronounced changes were observed in the long term treatment with sildenafil in comparison with BCNR. 45 days treatment with sildenafil up-regulated the expression of 28 genes related to angiogenesis such as EREG: 87.73, MMP 9: 23.51 PDGF: 12.00 and down regulated the expression of CTGF:-2.25 and PAI-3: -2.0 and hypoxia inducible factor 1 (EPAS 1: -2.00). CONCLUSIONS: Short and long term treatment with sildenafil after BCNR activates genes related to smooth muscle preservation and down regulates genes related to fibrosis. These results provide a mechanistic justification for the use of sildenafil and possibly other PDE5 inhibitors as protective therapy against corporal smooth muscle loss and fibrosis after radical prostatectomy. Source of Funding: NIH-SC1NS064611 from NINDS and NIGMS

Journal of Cardiac Failure, Aug 1, 2010

metropolitan Atlanta, GA area between 1/2008 and 6/2009. Results: Mean age of patients was 57.1 6... more metropolitan Atlanta, GA area between 1/2008 and 6/2009. Results: Mean age of patients was 57.1 6 12.0 years; 66.7% were male; 58.2% were white and 35.6% black; NYHA I/II/III/IV was 40.0/40.0/15.7/4.3%, respectively; median ejection fraction was 22.5% (interquartile range [IQR]: 15.0e35.0%); 41.5% had coronary artery disease (CAD) and 33.3% had diabetes; 43.5% had a biventricular pacemaker + / defibrillator. On follow-up (median: 20 months; IQR: 18-22 months), 52/147 patients (35.4%) experienced an event. Table 1 presents levels of MMPs and TIMPs according to event status. In univariate Cox models, TIMP-1 (p 5 0.002) and TIMP-2 (p 5 0.028) were positively associated with risk of adverse outcomes, while MMP-1 had an inverse U-shape association (p 5 0.008). In models controlling for age, gender, race, diabetes, CAD, creatinine, and ejection fraction, only TIMP-1 levels were associated with risk of adverse outcomes (HR per 0.1 ng/mL: 2.19; 95% CI: 1.08e4.47; p 5 0.031). Conclusions: Elevated serum TIMP-1 levels were strongly associated with adverse outcomes in this cohort of stable outpatients with systolic HF; this association was independent of clinical characteristics.

Journal of Cardiac Failure, Aug 1, 2014

ABSTRACT Abstract Bisphenol A is an environmental toxin released from plastics and has been shown... more ABSTRACT Abstract Bisphenol A is an environmental toxin released from plastics and has been shown to directly affect the coronary arteries and smooth muscle resulting in cardiac dysfunction leading to an increase in arrhythmias and coronary artery disease. Positive correlations between chemical dose exposure and increases in blood pressure have also been observed which could potentially lead to sustained hypertension, a primary cause of fibrosis. Whether such fibrosis also occurs in the myocardium remains to be determined. For the first time, the histological effects of chronic BPA exposure were investigated on the ventricular myocardium and on the media of a peripheral artery, in a rat model. Methods A total of 24 rats were divided into three groups: A) untreated control; B) vehicle control; C) BPA group. The BPA was dissolved in corn oil and group B and C received a daily IP injection of corn oil and 25 mg/kg BPA, respectively. After 3 months the animals were sacrificed, the heart was collected. Eight-μm sections were stained for collagen with Picrosirius red and Masson’s trichrome. The fibrotic changes were assessed by collagen deposition. The collagen content was determined by quantitative image analysis. Values were expressed as mean ± SEM. Results Significant diffuse histological changes were found in ventricles of rats in the BPA group (p<0.05). The BPA group had a greater mean collagen (2.2 ± 0.6%) compared to corn oil (1.5 ± 0.6%) and control group (1.5 ± 0.2%) although differences were not statistically significant. Conclusions Our data from this translational study suggest that chronic exposure to BPA may lead to cardiovascular fibrosis in rats through increased collagen deposition in the myocardium. However, clinical data in patients with prolonged BPA exposure are needed.

The Journal of Urology, Apr 1, 2009

International Journal of Molecular Sciences, Aug 19, 2019

Female stress urinary incontinence (FSUI) is prevalent in women with type 2 diabetes/obesity (T2D... more Female stress urinary incontinence (FSUI) is prevalent in women with type 2 diabetes/obesity (T2D/O), and treatment is not optimal. Autograph stem cell therapy surprisingly has poor efficacy. In the male rat model of T2D/O, it was demonstrated that epigenetic changes, triggered by long-term exposure to the dyslipidemic milieu, led to abnormal global transcriptional signatures (GTS) of genes and microRNAs (miR), and impaired the repair capacity of muscle-derived stem cells (MDSC). This was mimicked in vitro by treatment of MDSC with dyslipidemic serum or lipid factors. The current study aimed to predict whether these changes also occur in stem cells from female 12 weeks old T2D/O rats, a model of FSUI. MDSCs from T2D/O (ZF4-SC) and normal female rats (ZL4-SC) were treated in vitro with either dyslipidemic serum (ZFS) from late T2D/O 24 weeks old female Zucker fatty (ZF) rats, or normal serum (ZLS) from 24 weeks old female Zucker lean (ZL) rats, for 4 days and subjected to assays for fat deposition, apoptosis, scratch closing, myostatin, interleukin-6, and miR-GTS. The dyslipidemic ZFS affected both female stem cells more severely than in the male MDSC, with some gender-specific differences in miR-GTS. The changes in miR-GTS and myostatin/interleukin-6 balance may predict in vivo noxious effects of the T2D/O milieu that might impair autograft stem cell (SC) therapy for FSUI, but this requires future studies.

The Journal of Sexual Medicine, Dec 1, 2013

Introduction-Bisphenol A (BPA), released from plastics and dental sealants, is a suspected endocr... more Introduction-Bisphenol A (BPA), released from plastics and dental sealants, is a suspected endocrine disruptor and reproductive toxicant. In occupationally exposed workers, BPA has been associated with erectile dysfunction (ED). Aims-To determine whether long-term exposure to high doses of BPA in the rat affects serum levels of testosterone (T) and estradiol (E2), and induces corporal histopathology and resultant ED. Methods-Young rats were injected intraperitoneal (IP) injection daily with BPA at 25 mg/kg/day or vehicle (n = 8/group). Erectile function was measured at 3 months by cavernosometry and electrical field stimulation (EFS). BPA was assayed in serum, urine, and penile tissue, and serum T and E2 were determined. Quantitative Masson trichrome, terminal deoxynucleotidyl transferase dUTP nick end labeling, Oil Red O, immunohistochemistry for calponin, α-smooth muscle actin, and Oct 4 were applied to penile tissue sections. Protein markers were assessed by Western blots and 2-D minigels, and RNA by DNA microarrays. Main Outcome Measures-Erectile function, histological, and biochemical markers in corporal tissue. Results-In the BPA-treated rats, total and free BPA levels were increased in the serum, urine, and penile tissue while serum T and E2 levels were reduced. In addition, the corpora cavernosa demonstrated a reduction in smooth muscle (SM) content, SM/collagen ratio, together with an increase in myofibroblasts, fat deposits, and apoptosis, but no significant change in collagen content or stem cells (nuclear/perinuclear Oct 4). In the penile shaft, BPA induced a downregulation of Nanog (stem cells), neuronal nitric oxide synthase (nitrergic terminals), and vascular endothelial growth factor (angiogenesis), with genes related to SM tone and cytoskeleton upregulated 5-to 50-fold, accompanied by changes in the multiple protein profile. However, both cavernosometry and EFS were unaltered by BPA. Conclusions-While rats treated chronically with a high IP dose of BPA developed hypogonadism and a corporal histo-and molecular-pathology usually associated with ED, no changes were detected in erectile function as measured by EFS and cavernosometry. Further studies using alternate routes of BPA administration with various doses and length of exposure are needed to expand these findings.

BJUI, Jun 6, 2012

• To determine the gene expression profile of pelvic ganglia neurones after bilateral cavernosal ... more • To determine the gene expression profile of pelvic ganglia neurones after bilateral cavernosal nerve resection (BCNR) and subsequent treatment with sildenafil in relation to neurotrophic-related pathways. • Fisher rats aged 5 months were subjected to BCNR or sham operation and treated with or without sildenafil (20 mg/kg bodyweight in drinking water) for 7 days. • Total RNA isolated from pelvic ganglia was subjected to reverse transcription and then to quantitative reverse transcriptase-polymerase chain reaction (PCR) with the RATneurotrophic array. • Results were corroborated by real-time PCR and western blotting. • Another set of animals were injected with a fluorescent tracer at the base of the penis, 7 days before BCNR or sham operation, and were sacrificed 7 days after surgery. • Sections of pelvic ganglia were used for immunohistochemistry with antibodies against neurturin, neuronal nitric oxide synthase, tyrosine hydroxylase and glial cell line-derived neurotrophic factor receptor α2. • A down-regulation of the expression of neuronal nitric oxide synthase accompanied by changes in the level of cholinergic neurotrophic factors, such as neurturin and its receptor glial cell line-derived neurotrophic factor receptor α2, artemin, neurotrophin-4 and cilliary neurotrophic factor, was observed 7 days after BCNR in pelvic ganglia neurones. • Treatment with sildenafil, starting immediately after surgery, reversed all these changes at a level similar to that in sham-operated animals. • Sildenafil treatment promotes changes in the neurotrophic phenotype, leading to a regenerative state of pelvic ganglia neurones. • The present study provides a justification for the use of phosphodiesterase 5 inhibitors as a neuroprotective agent after BCNR.

The Journal of Sexual Medicine, Nov 1, 2012

Proteins, Jul 8, 2014

The protein structure prediction problem continues to elude scientists. Despite the introduction ... more The protein structure prediction problem continues to elude scientists. Despite the introduction of many methods, only modest gains were made over the last decade for certain classes of prediction targets. To address this challenge, a social-media based worldwide collaborative effort, named WeFold, was undertaken by thirteen labs. During the collaboration, the labs were simultaneously competing with each other. Here, we present the first attempt at "coopetition" in scientific research applied to the protein structure prediction and refinement problems. The coopetition was possible by allowing the participating labs to contribute different components of their protein structure prediction pipelines and create new hybrid pipelines that they tested during CASP10. This manuscript describes both successes and areas needing improvement as identified throughout

Urology, Aug 1, 2006

Objectives. Impotence, specifically corporal veno-occlusive dysfunction (CVOD), occurs after radi... more Objectives. Impotence, specifically corporal veno-occlusive dysfunction (CVOD), occurs after radical prostatectomy. It results from the effects of cavernosal nerve damage, which causes smooth muscle (SM) loss and an increase in collagen within the corpora. Recent reports have suggested that long-term treatment with phosphodiesterase-5 inhibitors after radical prostatectomy may prevent such changes. We aimed to determine whether bilateral cavernosal nerve resection (BCNX) in the rat leads to CVOD and whether long-term phosphodiesterase-5 inhibition ameliorates these histologic and functional impairments. Methods. Rats (n ϭ 7 to 11/group) underwent either the sham operation, BCNX, or BCNX plus 30 mg/L vardenafil in the drinking water. Before the rats were killed 45 days later, CVOD was assessed by dynamic infusion cavernosometry. The corpora underwent histochemistry/immunohistochemistry with quantitative image analysis for SM/collagen ratio, collagen III/I ratio, alpha-SM actin, inducible nitric oxide synthase (iNOS), proliferating cell nuclear antigen, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling as a marker of apoptosis. Results. Compared with the sham group, the BCNX rats demonstrated CVOD as measured by the drop rate, a 60% reduction in the SM/collagen ratio, a twofold increase in iNOS expression, and a threefold increase in intracorporeal apoptosis. Compared with the BCNX group, vardenafil increased both iNOS and proliferating cell nuclear antigen expression (SM cell replication), with normalization of the dynamic infusion cavernosometry drop rate and SM/collagen ratio. Conclusions. Long-term treatment with vardenafil may prevent CVOD after radical prostatectomy by preserving SM content and inhibiting corporal fibrosis possibly by its effect on iNOS.

The FASEB Journal, Apr 1, 2012

Journal of stem cell research & therapy, 2016

Critical Limb Ischemia (CLI) affects patients with Type 2 Diabetes (T2D) and obesity, with high r... more Critical Limb Ischemia (CLI) affects patients with Type 2 Diabetes (T2D) and obesity, with high risk of amputation and post-surgical mortality, and no effective medical treatment. Stem cell therapy, mainly with bone marrow mesenchymal, adipose derived, endothelial, hematopoietic, and umbilical cord stem cells, is promising in CLI mouse and rat models and is in clinical trials. Their general focus is on angiogenic repair, with no reports on the alleviation of necrosis, lipofibrosis, and myofiber regeneration in the ischemic muscle, or the use of Muscle Derived Stem Cells (MDSC) alone or in combination with pharmacological adjuvants, in the context of CLI in T2D. Using a T2D mouse model of CLI induced by severe unilateral femoral artery ligation, we tested: a) the repair efficacy of MDSC implanted into the ischemic muscle and the effects of concurrent intraperitoneal administration of a nitric oxide generator, molsidomine; and b) whether MDSC may partially counteract their own repair ...