Biomedical subjects

Susan Keay

Publications and source records attributed to Susan Keay.

9 recordsLinked to original sources

PubMed2006

EGF and HB-EGF modulate inward potassium current in human bladder urothelial cells from normal and interstitial cystitis patients.

Interstitial cystitis (IC) is an idiopathic condition characterized by bladder hyperalgesia. Studies have shown cytokine and purinergic signaling abnormalities in cultured bladder urothelial cells (BUC) from IC patients. We performed single-cell electrophysiological studies in both normal and IC BUC. A strongly inward rectifying potassium current with conductance of the Kir2.1 channel was identified in normal BUC. This current was significantly reduced in IC BUC. Kir2.1 protein and mRNA were detected in both IC and normal BUC. Epidermal growth factor (EGF) caused a dose-dependent decrease in the inward potassium current in normal BUC. EGF is secreted in higher amounts by IC BUC and is known to decrease Kir2.1 conductance by phosphorylation of Kir2.1. Genistein, a nonspecific phosphorylation inhibitor, increased the inward potassium current in IC BUC and blocked the effect of EGF on normal BUC. Treatment of IC BUC with heparin-binding epidermal growth factor-like growth factor (HB-EGF), previously shown to be secreted in lower amounts by IC BUC, significantly increased inward potassium current. These data show that the inward potassium current in BUC can be modulated by EGF and HB-EGF. Changes in BUC membrane potassium conductance caused by altered levels of EGF and HB-EGF may therefore play a role in the pathophysiology of IC.

Cells, Cultured↗

PubMed2005

Regulation of tight junction proteins and bladder epithelial paracellular permeability by an antiproliferative factor from patients with interstitial cystitis.

PURPOSE: Previous reports have suggested that the bladder epithelial barrier may be compromised in interstitial cystitis (IC). Antiproliferative factor (APF) is a small glycoprotein made specifically by bladder epithelial cells in patients with IC that induces changes in expression of certain epithelial cell proteins and profoundly inhibits cell growth. Therefore, we confirmed the increased permeability and decreased tight junction formation of bladder epithelial cell monolayers grown from biopsies in patients with IC compared to cells from normal controls. We then determined the effect of APF on the permeability of normal bladder epithelial cell monolayers and the expression of tight junction proteins. MATERIALS AND METHODS: Permeability was determined by measuring the C-mannitol and H-inulin flux between cells in confluent monolayers on Transwell culture plates (Corning, Corning, New York). Tight junction formation was assessed by immunofluorescence microscopy and the expression of specific proteins was determined by Western blot. RESULTS: APF treatment caused significant increases in the paracellular permeability of normal bladder epithelial cell monolayers and the attenuation of tight junctions compared to mock APF, similar to changes seen in IC cells. APF treatment also decreased expression of the tight junction proteins zonula occludens-1 and occludin. CONCLUSIONS: Because of its apparent effects on bladder epithelial cell tight junctions and paracellular permeability in vitro, APF may contribute to the leakiness of the bladder epithelial barrier seen in IC.

Adolescent↗

PubMed2004

Antiproliferative factor, heparin-binding epidermal growth factor-like growth factor, and epidermal growth factor in men with interstitial cystitis versus chronic pelvic pain syndrome.

OBJECTIVES: To determine whether men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) have urine markers previously described for patients with interstitial cystitis (IC; presence of antiproliferative factor [APF] activity, decreased levels of heparin-binding epidermal growth factor-like growth factor [HB-EGF], and increased levels of epidermal growth factor). METHODS: Clean catch urine specimens were collected from 41 symptomatic patients with CP/CPPS, 36 asymptomatic men without bladder disease who served as the control group, and 24 men with IC. APF activity was determined by (3)H-thymidine incorporation into primary normal adult human bladder epithelial cells. HB-EGF and epidermal growth factor levels were determined by enzyme-linked immunosorbent assay. RESULTS: Men with CP/CPPS did not differ significantly from asymptomatic controls for any of the three markers tested (P >0.49). In contrast, APF activity was present significantly more often and HB-EGF levels were significantly lower in the urine specimens from men with IC than in the specimens from controls or patients with CP/CPPS (P <0.00001 for all four comparisons). Although the epidermal growth factor levels also tended to be higher in the urine from patients with IC than in the urine from controls, the difference did not reach statistical significance (P = 0.06). CONCLUSIONS: These findings indicate that at least two of the urine biomarkers previously identified in women with IC (presence of APF activity and decreased levels of HB-EGF) are also found in men with IC, but not in men with CP/CPPS. This finding suggests that IC and CP/CPPS may be two different disorders with distinct pathophysiologies. It also confirms the utility of the presence of APF activity and HB-EGF levels as markers for IC in men, as well as in women, with this disorder.

Adolescent↗

PubMed2004

New theories in interstitial cystitis.

Interstitial cystitis (IC) is a chronic symptom-complex characterized by pathological sensation of the bladder (i.e. bladder pain in addition to augmented sensory signals such as urinary frequency and urgency) without evidence of bacterial cystitis or other identifiable lower urinary tract disease. Patients with IC typically describe feeling the urge to void frequently, as well as pain in the bladder and/or urethra. The painful sensation may be described as burning, pressure, sharp, or aching, and is often difficult for the patient to localize precisely. Multiple theories as to the cause of IC have been proposed with varying degrees of evidence. The current body of literature supports the idea that IC is associated with an intrinsic pathology of the bladder urothelial cells. The identification and complete characterization of antiproliferative factor (APF), which is uniquely expressed by urothelial cells in bladders affected by IC, are major advances in the understanding of IC. Additionally, urothelial cells have been likened to neurons because of their ability to express neuronal receptors and release neurotransmitters. The purinergic pathway has been shown to be upregulated in urothelial cells in bladders affected by IC. These new findings should help to direct the development of newer clinical treatments for IC. A complete understanding of IC will only be possible with parallel advances in both basic and clinical sciences.

Cystitis, Interstitial↗

PubMed2003

Changes in human bladder epithelial cell gene expression associated with interstitial cystitis or antiproliferative factor treatment.

Explanted bladder epithelial cells from patients with interstitial cystitis (IC) have been shown to differ from explanted control cells in several ways, including production of an antiproliferative factor (APF), altered production of certain epithelial growth factors, and rate of proliferation. To better understand the role of the APF in abnormal bladder epithelial cell proliferation in IC, we studied gene expression patterns in normal bladder epithelial cells treated with APF vs. mock APF and compared them to expression patterns in IC vs. normal cells using microarray analysis. Oligo-dT-primed total cellular RNA was labeled with [(33)P]dCTP and hybridized to GeneFilter GF211 microarray membranes (Research Genetics) containing cDNA for 3,964 human genes. Thirteen genes that function in epithelial cell proliferation or differentiation were consistently differentially expressed in both IC (compared with control) and APF-treated (compared with mock APF-treated) normal bladder epithelial cells. The general pattern of gene expression in IC and APF-treated cells suggested a less proliferative phenotype, with increased expression of E-cadherin, phosphoribosylpyrophosphate synthetase-associated protein 39, and SWI/SNF complex 170-kDa subunit, and decreased expression of vimentin, alpha2-integrin, alpha1-catenin, cyclin D1, and jun N-terminal kinase 1; these findings were confirmed for the structural gene products (E-cadherin, vimentin, alpha2-integrin, and alpha-catenin) by immunohistochemistry. These results are compatible with the previously noted decreased proliferation rate of IC and APF-treated normal cells, and indicate that the mechanism whereby APF inhibits cell proliferation may involve both downregulation of genes that stimulate cell proliferation along with upregulation of genes that inhibit cell growth.

Adolescent↗

PubMed2003

Comparison of APF activity and epithelial growth factor levels in urine from Chinese, African-American, and white American patients with interstitial cystitis.

OBJECTIVES: Interstitial cystitis (IC) is a chronic bladder disorder for which the etiology is unknown. We have previously shown that antiproliferative factor (APF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), and epidermal growth factor (EGF) are sensitive and specific biomarkers for IC in white American patients. Because little is known about the epidemiology of this disorder, it is unclear whether these factors would also be useful biomarkers for IC in patients from different racial groups and/or geographic locations. METHODS: Urine specimens were collected from Chinese, white American, and African-American women with IC and age and race-matched asymptomatic normal control women. APF activity was determined by (3)H-thymidine incorporation into primary normal adult human bladder epithelial cells in vitro. The HB-EGF and EGF urine levels were determined by enzyme-linked immunosorbent assay. RESULTS: The Chinese, African-American, and white American women with IC had significantly greater urine APF activity (P <0.000001, P = 0.0008, and P <0.000001, respectively), lower urine HB-EGF levels (P <0.000001, P = 0.02, and P <0.000001, respectively), and greater urine EGF levels (P <0.000001, P = 0.002, and P <0.000001, respectively), than their matched asymptomatic controls. CONCLUSIONS: These findings confirm the utility of APF, HB-EGF, and EGF as biomarkers for IC in patients from three different racial groups and two different countries.

Adult↗

PubMed2003

Decreased in vitro proliferation of bladder epithelial cells from patients with interstitial cystitis.

OBJECTIVES: To determine whether explanted bladder epithelial cells from patients with interstitial cystitis (IC) display intrinsically decreased rates of proliferation in vitro, and to compare the growth rates of untreated IC and normal bladder cells with the rates of normal cells treated with a purified antiproliferative factor (APF) at levels found in urine from patients with IC. METHODS: Epithelial cell explants were prepared from the bladder biopsies of 4 patients with IC and 2 asymptomatic controls. Cell proliferation was determined by serial counting of trypan blue-negative cells. APF and mock APF were purified chromatographically, and activity was determined by (3)H-thymidine incorporation into primary normal bladder epithelial cells. Heparin-binding epidermal growth factor-like growth factor and epidermal growth factor were measured by enzyme-linked immunosorbent assay. RESULTS: Bladder epithelial cells from patients with IC proliferated significantly less than did control cells by day 2 after serum starvation (P = 0.02). Similar inhibition of the proliferation rate was seen in control cells treated with APF; APF-induced changes in heparin-binding epidermal growth factor-like growth factor, but not epidermal growth factor, production by cells were associated with changes in growth rates. CONCLUSIONS: The proliferation rate of explanted bladder epithelial cells from patients with IC in serum-free medium was significantly less than that of control cells, indicating an intrinsic abnormality in IC cell proliferation. This abnormality may be caused by APF, which induces reversible inhibition of heparin-binding epidermal growth factor-like growth factor production and normal bladder epithelial cell proliferation.

Adult↗

PubMed2003

Current and future directions in diagnostic markers in interstitial cystitis.

Interstitial cystitis (IC) is a chronic bladder disorder of unknown etiology that is often diagnosed by symptom criteria with or without cystoscopic findings. Several potential diagnostic markers have recently been described that may facilitate diagnosis of this disorder. A summary of the literature and a discussion regarding these biomarkers is provided, along with a brief discussion of new biomarkers presented at the meeting.

Biomarkers↗

PubMed2002

Cardiac Transplantation: Pre-transplant Infectious Diseases Evaluation and Post-transplant Prophylaxis.

Screening of recipients and donors of cardiac allografts for infectious pathogens, and the use of appropriate immunization and antimicrobial prophylaxis strategies, remain important for the control of infection following heart transplantation. However, the risk of infectious complications in a particular patient must often be weighed against the risk of delaying or denying allograft transplantation. In addition, the ongoing degree of immunosuppression and its contribution to the risk for infectious complications should also be considered to guide the length of prophylactic antimicrobial therapy and provide optimal patient care.

Journal Article↗