Cellular Proliferation Index Research Articles

Clinical and Pathological Predictors of the Response to Neoadjuvant Anthracycline Chemotherapy in Locally Advanced Breast Cancer

The aim of this study is to determine clinical and histopathological characteristics correlated to responsiveness to anthracycline-based neoadjuvant chemotherapy in breast cancer. We studied primary tumor specimens with local advanced breast cancer from 40 patients. Patients received anthracycline-based chemotherapy. Neoadjuvant regimen consisted in 600 mg/m2 5-fluorouracil, 60 mg/m2 doxorubicin, and 600 mg/m2 cyclophosphamide (FAC). The World Health Organization criteria were used to classify the tumors. We performed immunohistochemical staining for ER, PgR, HER-2, PCNA (proliferation cell nuclear antigen), Ki-67, p53, and Bcl-2. Clinical and histopathological characteristics were associated with clinical response and histopathological changes induced by chemotherapy. The mean age was 47 +/- 14 yr. Twenty-three percent of patients were in stage IIB and 77% were in stages IIIA and IIIB. Seven percent of patients had progression of the disease. Stable disease was observed in 42% of patients and 45% had partial response. Only 7% of patients had a complete response. Factors associated with a better and major percentage of clinical response were the administration of doxorubicin-based chemotherapy, administration of more than three cycles, clinical N1, atypia, more than 10 mitosis per high-power field, moderate to severe SBR grade, and a major index of cellular proliferation. We found that tumors with large volumes, N2 node status, low cellular proliferation rate, positive immunoreactivity to p53, and low differentiation grade have a lower response to neoadjuvant chemotherapy with anthracycline. These patients could benefit from a different chemotherapy scheme to obtain a better control and resection.

Cellular uptake of 99mTcN-NOET in human leukaemic HL-60 cells is related to calcium channel activation and cell proliferation

A major goal of nuclear oncology is the development of new radiolabelled tracers as proliferation markers. Intracellular calcium waves play a fundamental role in the course of the cell cycle. These waves occur in non-excitable tumour cells via store-operated calcium channels (SOCCs). Bis(N-ethoxy, N-ethyldithiocarbamato) nitrido technetium (V)-99m ((99m)TcN-NOET) has been shown to interact with L-type voltage-operated calcium channels (VOCCs) in cultured cardiomyocytes. Considering the analogy between VOCCs and SOCCs, we sought to determine whether (99m)TcN-NOET also binds to activated SOCCs in tumour cells in order to clarify the potential value of this tracer as a proliferation marker. Uptake kinetics of (99m)TcN-NOET were measured in human leukaemic HL-60 cells over 60 min and the effect of several calcium channel modulators on 1-min tracer uptake was studied. The uptake kinetics of (99m)TcN-NOET were compared both with the variations of cytosolic free calcium concentration measured by indo-1/AM and with the variations in the SG2M cellular proliferation index. All calcium channel inhibitors significantly decreased the cellular uptake of (99m)TcN-NOET whereas the activator thapsigargin induced a significant 10% increase. In parallel, SOCC activation by thapsigargin, as measured using the indo-1/AM probe, was inhibited by nicardipine. These results indicate that the uptake of (99m)TcN-NOET is related to the activation of SOCCs. Finally, a correlation was observed between the tracer uptake and variations in the proliferation index SG2M. The uptake of (99m)TcN-NOET seems to be related to SOCC activation and to cell proliferation in HL-60 cells. These results indicate that (99m)TcN-NOET might be a marker of cell proliferation.

Techniques to assess the proliferative potential of brain tumors

Assessment of brain tumor proliferative potential provides important prognostic information that supplements standard histopathologic grading. Many laboratories rely on mitotic figures to quantify the proliferative potential of brain tumors, but this conventional cellular proliferative index is subject to inter-observer variability and not consistently predictive for low-and high-grade tumors. Recent advancements in technology have made it possible to use proliferative indices as a standard supplement in pathology laboratories. Non-invasive tumor tissue measurements of cell proliferation can be performed using- bromodeoxyuridine labeling index (BrdU LI), flow cytometry (FCM), MIB-1 antibody to the Ki-67 antigen (MIB-1), proliferating cell nuclear antigen (PCNA), and argyrophilic nucleolar organizing regions (AgNOR). Each of these assays has been described in the literature with respect to its ability to predict tumor grade or outcome. At the present time MIB-1 and AgNOR are the simplest and most reliable of these techniques. In addition, advances in our understanding of the genetic alterations associated with proliferation promise to provide more specific markers of proliferative potential. Beyond the pathology laboratory, radiographic studies such as positron emission tomography (PET), single photon emission computed tomography (SPECT), and most recently magnetic resonance spectroscopy (MRS) have been used as follow-up measures, assessing response to treatment and tumor recurrence, rather than as predictors of response to treatment. These radiographic tools, however, have the potential to provide an assessment of tumor proliferation without the need for invasive measures. In this article, we present a review of the current techniques utilized to understand the proliferative potential of brain tumors.

Telomerase activity and cell proliferation index in cholesteatoma

Conclusions. Telomerase activity was expressed in cholesteatomas, and cellular proliferation was significantly higher in cases where the telomerase activity was positive. Telomerase activity was also closely related with cellular proliferation in chronic hyperproliferating tissues such as cholesteatomas. Objective. Telomerase activity is detected in most malignant tumors and is also known to have a close relationship with cell proliferation. Cholesteatoma shows cellular hyperproliferation. We studied telomerase activity in cholesteatoma and its relationship with cellular proliferation and clinical findings. Material and methods. Cholesteatoma tissue was obtained from 40 patients during middle ear surgery. Telomerase activity was measured using a telomeric repeat amplification protocol method. As a cellular proliferation index, expression of Ki-67 was measured by means of immunohistochemical staining. Posterior auricular skin was used as a control. Telomerase activity was compared with Ki-67 expression. Clinical features such as hearing loss, the extension of cholesteatoma, the degree of bone destruction and the cause of cholesteatomas were compared with telomerase activity and the cellular proliferation index. Results. Telomerase activity was positive in 21/40 cholesteatomas (52.5%), but absent in the control group. The average Ki-67 labeling index in the cholesteatoma group was 32.84±10.13, higher than that in the control group (21.83±7.76) (p<0.05). The average Ki-67 labeling indices of the 21 telomerase activity-positive and 19 telomerase activity-negative cholesteatomas were 37.76±8.53 and 27.39±9.06, respectively. The Ki-67 labeling index was significantly higher in telomerase-positive cholesteatomas (p<0.05). The clinical features did not show a relationship with either telomerase activity or the cellular proliferation index.

CpG hypermethylation of MDR1 gene contributes to the pathogenesis and progression of human prostate cancer.

Multidrug resistance 1 (MDR1) gene encodes for P-glycoprotein (P-gp), a Mr 170,000 transmembrane calcium-dependent efflux pump that is inactivated in prostate cancer. We hypothesize that inactivation of the MDR1 gene through CpG methylation contributes to the pathogenesis and progression of prostate cancer. To test this hypothesis, CpG methylation status of the MDR1 promoter and its correlation with clinicopathological findings were evaluated in 177 prostate cancer samples and 69 benign prostate hypertrophy (BPH) samples. Cellular proliferation index and apoptotic index were determined by proliferating cell nuclear antigen (PCNA) and single-strand DNA immunostaining, respectively. After 5-aza-2'-deoxycytidine treatment, increased expression of MDR1 mRNA transcript was found in prostate cancer cell lines (DU145, DuPro, and ND1). MDR1 methylation frequency was significantly higher in prostate cancer samples compared with BPH samples (54.8 versus 11.6%, respectively, P < 0.001). Logistic regression analysis revealed that PC patients are 11.5 times more likely to have MDR1 methylation than BPH patients (95% confidence interval 4.87-27.0) and that MDR1 methylation is independent of the age. Significant correlation of MDR1 methylation was observed with high pT category (P < 0.001), high Gleason sum (P = 0.008), high preoperative prostate-specific antigen (P = 0.01), and advancing pathological features. In addition, PCNA-labeling index were significantly higher in methylation-specific PCR (MSP)-positive than in MSP-negative prostate cancer samples (P = 0.048). In contrast, no significant difference in apoptotic index was found between MSP-positive and -negative prostate cancer samples. These findings suggest that CpG hypermethylation of MDR1 promoter is a frequent event in prostate cancer and is related to disease progression via increased cell proliferation in prostate cancer cells.

Fresh and cultured buccal cells as a source of mRNA and protein for molecular analysis

We developed a method for obtaining viable buccal cells from mouthwash samples for use as a source of mRNA and protein. Immunofluorescent analysis showed that most cells were derived from nonkeratinized parabasal epithelia, with a minor proportion of proliferative cells. Gene expression was detected in buccal cells using reverse transcription PCR, Western blot analysis, and immunofluorescence. Using a keratinocyte-specific medium, buccal cells could be cultured on Matrigel-coated permeable filters for up to 2 weeks while maintaining the expression of some epithelial-specific markers, including cytokeratin 13, cytokeratin 10, transferrin receptor, and beta-integrin. The basal marker cytokeratin 14 and Ki67, an indicator of cellular proliferation, were detected in a few cells. We show that buccal cells can be obtained from a noninvasive procedure for use as a source of material for biochemical analyses. A population of the buccal cells can be maintained in culture for up to 2 weeks using keratinocyte-specific medium in combination with extracellular matrix.

Recent progress in predictive biomarkers for metastatic recurrence of human hepatocellular carcinoma: a review of the literature.

Molecular markers (biomarkers) for hepatocellular carcinoma (HCC) metastasis and recurrence could provide additional information to that gained from traditional histopathological features. A large number of biomarkers have been shown to have potential predictive significance. One important aspect of this is to detect the transcripts of tumor-associated antigens (such as AFP, MAGEs, and CK19), which are proposed as predictive markers of HCC cells disseminated into the circulation and for metastatic recurrence. Another important aspect is to analyze the molecular markers for cellular malignancy phenotype, including DNA ploidy, cellular proliferation index, cell cycle regulators, oncogenes, and tumor suppressors (especially p53 gene), as well as telomerase activity. Molecular factors involved in the process of HCC invasion and metastasis, including adhesion molecules (E-cadherin, catenins, ICAM-1, laminin-5, CD44 variants, osteopontin), proteinases responsible for the degradation of extracellular matrix (MMPs, uPA system), as well as angiogenesis regulators (such as VEGF, intratumor MVD), have also been shown to be potential predictors for HCC metastatic recurrence and clinical outcomes. One important new trend is to widely delineate biomarkers with genomic and proteomic expression with reference to predicting metastatic recurrence, molecular diagnosis, and classification, which has been drawing more attention recently. Body fluid (particularly blood and urine) testing for biomarkers is easily accessible and more useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum and its genetic alterations is another important direction. More attention should be paid to these areas in the future. As understanding of tumor biology deepens, more and more new biomarkers with high sensitivity and specificity for HCC metastatic recurrence could be found and routinely used in clinical assays. However, the combination of the pathological features and some of the biomarkers mentioned above seems to be more practical up to now.

Endothelial cell proliferation associated with abrupt reduction in shear stress is dependent on reactive oxygen species.

We have shown previously that flow-adapted endothelial cells respond to cessation of flow with cell membrane depolarization and increased production of reactive oxygen species, resulting in activation of transcription factors and increased DNA synthesis. This study utilized flow cytometry to evaluate cellular proliferation with ischemia and to determine the role of reactive oxygen species and apoptosis. PKH26-labeled rat pulmonary microvascular endothelial cells were seeded in an artificial capillary system and subjected to flow at 5 dynes/cm(2) for 96 h or for 72 h followed by 24 h of simulated "ischemia." Ischemia resulted in a 2.5-fold increase in the cellular proliferation index. Cell-cycle analysis showed G0/G1 arrest and decreased S plus G2/M during flow adaptation, whereas ischemia resulted in a three-fold increase of cells in S plus G2/M phases. Apoptotic cells as detected by TUNEL and annexin V binding assays were ~5% of total cells with no differences between static, flow-adapted, and "ischemic" groups. Reactive oxygen species production during a 1-h period following onset of ischemia was confirmed by oxidation of the fluorophore, dichlorofluorescein, and was inhibited by cromakalim, a K(ATP) channel agonist, or diphenyleneiodonium, a flavoprotein inhibitor. Cromakalim and diphenyleneiodonium also markedly inhibited cell proliferation in the flow-adapted ischemic cells, but had no effect on subconfluent cells cultured under static conditions. These results indicate reactive oxygen species-dependent endothelial cell proliferation in flow-adapted microvascular endothelial cells as a response to ischemia and indicate that this response is not a consequence of apoptosis.

Pathologic characterization of prostate cancers with a very low serum prostate specific antigen (0–2 ng/mL) incidental to cystoprostatectomy: is PSA a useful indicator of clinical significance?

Cystoprostatectomy specimens removed for bladder malignancy (1988–2000) at two referral centers (Mayo Clinic, Rochester, MN, The University Hospital of Innsbruck, Innsbruck, Austria) were examined for the coincidental finding of prostate cancer (PCA). Centralized examination of the prostate by a single uropathologist was performed if at the time of surgery the patient’s serum PSA was ≤2.0 ng/mL and there were no suspicious lesions by digital prostate examination. Pathologic grade, stage, morphometric volume, number of tumor foci and association with areas of high grade prostatic intraepithelial neoplasia (HGPIN) were assessed by light microscopy. DNA ploidy and cellular proliferative index were assessed through digital image analysis. Clinically significant cancers were defined as tumors with ≥0.5 cc volume, Gleason 4 or 5 architecture, pT3, positive surgical margin, multifocality >3, nondiploid DNA content or proliferation index >5%. From nearly 1600 cystoprostatectomy specimens, 129 met the enrollment criteria. Thirty-patients (23%) within this group had PCA identified. Sixty percent of these tumors met the criteria for a clinically significant cancer. Nondiploid nuclear content was present in 17%. HGPIN was present in 70% and directly abutting carcinoma in 86% of prostates. The biologic activity of PCA appears to be independent of serum PSA. Any future definition of a clinically significant PCA should not be solely based upon histologic criteria, but needs to encompass clinical parameters (age, co-morbidities) and a noninvasive assessment of tumor volume and biologic doubling time.

Ovarian tissue banking and fertility preservation in cancer patients: histological and immunohistochemical evaluation

Objective A combination of chemotherapy and radiotherapy in young females with cancer has greatly enhanced the life expectancy of these patients, even if these treatments have a highly deleterious effect on the ovary and cause a severe depletion of the follicular store. Cryopreservation of ovarian tissue before chemotherapy and/or radiotherapy, followed by autograft after remission or in in vitro maturation, could restore gonadal function and fertility. The aim of this study is to verify the efficiency of the ovarian tissue cryopreservation procedure by histological and immunohistochemical analyses. Methods Ovarian tissue was obtained by laparoscopy from 22 patients affected with different malignant diseases. Tissue specimens were frozen using a combination of PROH (1,2-propanediol) and sucrose as cryoprotectants, and the cryopreservation protocol used consisted of a slow freezing–rapid thawing program. Both fresh and frozen/thawed tissues were embedded in paraffin blocks for histological and immunohistochemical analyses. Results Good stromal and follicular morphology was found in fresh and frozen/thawed tissue. No significant differences were found in follicular density, distribution, and diameters in fresh and frozen/thawed tissue. Follicle immunohistochemical analysis showed a high percentage of negative staining for both estrogen receptor (ER) (100% both in fresh and frozen/thawed specimens) and progesterone receptor (PR) (97% versus 91%, respectively). Regarding the Ki67 protein, positive staining was found in both the granulosa cells and/or the oocytes (36% in fresh and 56% in frozen/thawed). For the Bcl2 protein, positive staining was observed in the follicle granulosa cells but not in the oocytes in 74% of the fresh and in 79% of the frozen/thawed specimens. For the stromal cells, ER showed a negative staining distribution in 97% of the fresh and 100% of the frozen/thawed specimens. The stroma staining distribution was diffuse/focal in fresh versus frozen/thawed specimens (50% versus 74% respectively) for PR, patch/focal (70% versus 80%, respectively) for Ki67 protein, and diffuse (55% versus 54%, respectively) for Bcl2. Conclusions These results suggest that human ovarian tissue morphology, antigenicity, cellular proliferation, and anti-apoptotic index were well preserved by cryopreservation in PROH and sucrose.

Amino acids induce indicators of response to injury in glomerular mesangial cells.

High-protein diets exacerbate glomerular hyperfiltration and the progression of diabetic nephropathy. The purpose of this study was to determine whether amino acids also produce nonhemodynamic injury in the glomerulus. When rat mesangial cells were cultured with an amino acid mixture designed to replicate the composition in plasma after protein feeding, production of mRNA (Northern blot analysis) and/or protein (ELISA or Western blot analysis) for transforming growth factor-beta1 (TGF-beta1), fibronectin, thrombospondin-1 (TSP-1), and collagen IV were enhanced in a manner comparable to a culture with high glucose (30.5 mM). The bioactive portion of total TGF-beta (NRK assay) increased in response to amino acids. The TSP-1 antagonist LSKL peptide reduced bioactive TGF-beta and fibronectin, indicating the dependence of TGF-beta1 activation on TSP-1. DNA synthesis ([3H]thymidine incorporation), an index of cellular proliferation, increased in response to amino acids and was further enhanced by culture with increased levels of both amino acids and glucose. TGF-beta1 and matrix proteins increased when mesangial cells were cultured with excess l-arginine (2.08 mM) alone. Although l-arginine is the precursor of nitric oxide (NO), such responses to amino acids do not appear to be mediated through increased NO production. NO metabolites decreased in the media, and these responses to mixed amino acids or l-arginine were not prevented by NO synthase inhibition. In conclusion, amino acids induce indicators of response to injury in mesangial cells, even when hemodynamic stress is absent. In conditions associated with increased circulating amino acids, such as diabetes and/or a high-protein diet, direct cellular effects could contribute to glomerular injury.

Proliferative activity in stenotic human aortocoronary bypass grafts

Background: Aortocoronary bypass graft disease is responsible for long-term failure of autologous vein grafts. The analyses of proliferation and cell type characterisation in human bypass grafts harvested during re-do surgery make it possible to investigate the cellular processes leading to bypass graft failure. Methods: 30 stenotic vein grafts and 25 control veins were explantated during re-do heart surgery procedures. The total area and cell count of the neointima, media and adventitia were calculated computer-assisted. Actively proliferating cells were identified using antibody to Ki-67 and positive cells were determined by double-label immunocytochemistry with SMC α-actin, CD 31 (endothelial cells), CD 68 (macrophages) and CD 45 (T-lymphocytes). Results: Active proliferation was detected in different cell types with an average proliferation index of 0.15%, 0.18% and 0.086% for neointima, media and adventitia. Only 9% of proliferating cells in the neointima were SMC (not identified cells 40%); correspondingly, 14% SMC (not identified cells 33%) were detected in the media. Endothelial cells turned out to be the predominant proliferating cell type in all sections of the vessel wall. Conclusion: Proliferation in our series of stenotic vein grafts occurred at a low level, but was significantly higher compared to native control veins. While proliferation may play an important role in early lesions, our data clearly show low proliferation activity in advanced graft lesions. The identification of proliferating macrophages and T-lymphocytes implicate an additional inflammatory component in the development of human bypass graft disease. Summary: To clarify the role of cellular proliferation in human aortocoronary bypass grafts, we characterized the cellular composition and proliferation index in 30 stenotic saphenous vein grafts in comparison to 25 native veins. Proliferation in our series of stenotic vein grafts occurred at a low level, but was significantly higher compared to native control veins.

Prognostic relevance of p53 protein expression in glioblastoma

TP53 plays a key role in cellular response to DNA-damaging agents, and mutation of this gene, which is associated with immunohistochemically detectable p53 protein accumulation, may influence response to chemo- and radiotherapy. We investigated immunohistochemically the influence of p53 protein accumulation in 114 consecutive cases of primary glioblastoma treated by surgery and adjuvant radio- and chemotherapy. In addition, we determined cellular proliferation index using the antibody MIB-1 and apoptotic index of tumor cells using the TUNEL-assay. Twenty-nine patients (25.4%) were considered as positive with regard to p53 protein expression (>50% p53 immunostained tumor cells). Patients with p53 positive glioblastomas were significantly younger (mean age 54.4+/-2 years) than those with p53 negative tumors (mean age 61.4+/-1.1 years) (p=0.002, Mann-Whitney test). While no significant difference in apoptotic index was found, we observed a significantly higher MIB-1 labeling index (LI) in patients with p53 positive tumors (median LI: 36.4%) compared to p53 negative ones (median LI: 23.8%) (p=0.005, Mann-Whitney test). p53 protein expression was associated with significantly longer survival in univariate analysis (p=0.0399, log-rank test). In multivariate analysis of overall survival (Cox regression) only postoperative Karnofsky performance status remained as independent prognostic factor. We conclude that glioblastoma patients with immunohistochemically detectable p53 protein expression, who received adjuvant radio- and chemotherapy, have a significantly better overall survival, possibly due to increased sensitivity to this adjuvant treatment.

Alterações cromossômicas causadas pela radiação dos monitores de vídeo de computadores

Concerns were raised about the potential damaging effects of electromagnetic field (EMF) radiation emissions of ELF (extremely low frequency) and VLF (very low frequency) computer video display monitors (VDM), it was assessed the frequency of structural chromosome abnormalities and investigated the cell cycle kinetics in individuals occupationally exposed to VDM radiation. Chromosome aberrations were investigated in 2,000 first cell cycle metaphases obtained after 48-hour cultures of peripheral blood lymphocytes drawn from 10 individuals occupationally exposed to VDM radiation (group E) and 10 controls (group C). Cell cycle kinetics was studied using the mitotic index (MI) and cellular proliferation index (CPI). Statistical analysis showed significantly higher frequencies of anomalous metaphases (E=5.9%; C=3.7%) and anomaly/cell (E=0.066+/-0.026; C= 0.040+/-0.026) in individuals exposed to VDM radiation. The most common cytogenetic alterations seen were chromatid breaks at frequencies of 0.034+/-0.016 in group E and 0.016+/-0.015 in group C. There was no significant difference between MI and CPI frequencies in both groups. The study findings suggest genotoxic effects of EMF emissions revealed by the higher frequency of chromatid breaks in individuals exposed to VDM radiation. However, there is a need of further studies on EMF genetic effects using other investigation methods.

Dietary genistin stimulates growth of estrogen-dependent breast cancer tumors similar to that observed with genistein.

The estrogenic soy isoflavone, genistein, stimulates growth of estrogen-dependent human breast cancer (MCF-7) cells in vivo. Genistin is the glycoside form of genistein and the predominant form found in plants. It is generally believed that genistin is metabolized to the aglycone genistein in the lower gut. However, it is unclear if the rate of metabolism of genistin to genistein is sufficient to produce a level of genistein capable of stimulating estrogen-dependent breast cancer cell growth. Our hypothesis was that dietary genistin would stimulate tumor growth similar to that observed with genistein in athymic mice. To test this hypothesis, genistin or genistein was fed to athymic mice containing xenografted estrogen-dependent breast tumors (MCF-7). Mice were fed either genistein at 750 p.p.m. (parts per milllion) or genistin at 1200 p.p.m., which provides equal molar concentrations of aglycone equivalents in both diets. Tumor size was measured weekly for 11 weeks. At completion of the study, half of the animals per treatment group were killed and tumors collected for evaluation of cellular proliferation and estrogen-responsive pS2 gene expression. Incorporation of bromo-deoxyuridine into cellular DNA was utilized as an indicator of cellular proliferation. Dietary genistin resulted in increased tumor growth, pS2 expression and cellular proliferation similar to that observed with genistein. The remaining mice were switched to diets free of genistin and genistein. When mice were placed on isoflavone free diets, tumors regressed over a span of 9 weeks. Next, we examined how effectively and where metabolism of genistin to genistein occurred in the digestive tract. We present evidence that demonstrates conversion of genistin to its aglycone form genistein begins in the mouth and then continues in the small intestine. Both human saliva and the intestinal cell-free extract from mice converted genistin to genistein. In summary, the glycoside genistin, like the aglycone genistein, can stimulate estrogen-dependent breast cancer cell growth in vivo. Removal of genistin or genistein from the diet caused tumors to regress.

A comparison of four stent designs on arterial injury, cellular proliferation, neointima formation, and arterial dimensions in an experimental porcine model

The stent-artery interactions of different stent designs have implications for their clinical effects. We studied four different stent designs to compare their effects on arterial injury, cellular proliferation, neointima formation, and arterial dimensions. Eighteen nonatherosclerotic miniswine underwent random placement of 52 coronary stents (3.0 mm), including self-expanding nitinol stents (no postdilation; Radius, n = 13) and balloon-expandable stents (8 atm × 45 sec; Palmaz-Schatz, n = 13; BX, n = 12; and Multilink, n = 14). Cellular proliferation was determined by S-phase labeling with BrdU at 7, 14, and 28 days. Proliferation, injury scores, and arterial morphometry were blindly evaluated. All four stent designs had similar injury scores, cellular proliferation indexes (neointimal and medial), and adventitial areas. Nitinol stents resulted in a twofold increase in neointimal area and thickness in 28-day vessels (P = 0.002). However, lumen area was similar for all stent designs because of an offsetting expansion in vessel area in nitinol stents (20% greater than balloon-expandable stents) occurring between 7 and 14 days after stent deployment (P = 0.03). Reduced neointimal cell density in nitinol stents (20% less than balloon-expandable stents, P = 0.012) suggests that extracellular matrix expansion accounts for the larger neointima in nitinol stents. Self-expansion of nitinol stents within normal porcine arteries results in a similar degree of arterial injury compared to balloon-expandable stent designs. Progressive enlargement of nitinol stents between 7 and 14 days after deployment is associated with the development of a larger, matrix-rich neointima, with a preserved lumen area. Cathet Cardiovasc Intervent 2001;53:420–425. Published 2001 Wiley-Liss, Inc.

Retinoic acid enhances lung growth after pneumonectomy

Background. We sought to identify the role of retinoic acid (RA) upon lung growth. RA has a role in perinatal lung development, and we hypothesized that exogenous RA would enhance postpneumonectomy compensatory lung growth.Methods. Utilizing the postpneumonectomy rat model, we studied the impact of RA upon contralateral lung growth. Adult Sprague-Dawley rats were divided into three groups. Group S underwent a sham left thoracotomy, group P underwent left pneumonectomy, and group R underwent left pneumonectomy with administration of exogenous RA (0.5 μg/g/day intraperitoneally). We then quantitated right lung growth after 10 and 21 days. Lung weight and volume were expressed as a ratio to the final body weight (lung weight and volume indices, LWI and LVI). Epidermal growth factor receptor (EGFR) expression was quantitated using Western blot analysis. Cellular proliferation index (CPI) was determined using BrdU immunostaining.Results. LWI, LVI, CPI, and EGFR expression at 21 days were significantly higher in group R versus S and P. At the 10-day interval, both LWI and LVI were significantly higher in group R versus S and P.Conclusions. RA administration markedly enhances lung growth after pneumonectomy, as evidenced by increases in LWI, LVI, and CPI. Upregulation of EGFR expression was associated with these effects.

Healed plaque ruptures and sudden coronary death: evidence that subclinical rupture has a role in plaque progression.

Subclinical episodes of plaque disruption followed by healing are considered a mechanism of increased plaque burden. Detailed pathological studies of healed ruptures, however, are lacking. We identified acute and healed ruptures from 142 men who died of sudden coronary death and performed morphometric measurements of plaque burden, luminal stenosis, and smooth muscle cell phenotype. Healed ruptures were found in 61% of hearts and were associated with healed myocardial infarction, increased heart weight, dyslipidemia, and diabetes. Multiple healed rupture sites with layering were frequently found in segments with acute and healed rupture; the percent area luminal narrowing increased with increased numbers of healed sites of previous rupture. The underlying percent luminal narrowing for acute ruptures (mean 79+/-15%) exceeded that for healed ruptures (mean 66+/-14%, P:=0.0001), and the area within the internal elastic lamina was significantly less in healed ruptures than in acute ruptures, when segments were grouped by distance from the ostium. Healed ruptures favored the accumulation of immature smooth muscle cells at repair sites, with a cellular proliferation index of 0.40+/-0.09%, significantly higher than the index at the sites of rupture (P:=0.008). These data provide evidence that silent plaque rupture is a form of wound healing that results in increased percent stenosis. Healed ruptures occur in arteries with less cross-sectional area luminal narrowing than acute ruptures and are a frequent finding in men who die suddenly with severe coronary atherosclerosis.

Aldosterone mediates angiotensin II-stimulated rat vascular smooth muscle cell proliferation.

Aldosterone, possibly locally generated, has been suggested to have a role in potentiating angiotensin II (AII)-stimulated hypertrophy of cultured vascular smooth muscle cells. To examine the possibility that aldosterone may mediate the proliferative actions of AII, rat aortic smooth muscle cells (RASMCs) in culture were treated with AII in the presence and absence of the specific AII type 1 receptor (AT1) antagonist, losartan, and aldosterone was assayed in culture medium extracts by radioimmunoassay. AII significantly enhanced aldosterone formation (at 10(-8) M: 123.8+/-14.85 vs control 71. 28+/- 8.71 fmol/10(5) cells, P<0.05; at 10(-7) M: 172.38+/-33.44, P<0.05), but not in the presence of losartan (at 10(-8) M: 53. 71+/-18.73, P>0.05; at 10(-7) M: 89.68+/-25.05, P>0.05). In other studies, the reverse transcriptase-polymerase chain reaction, performed on RNA extracted from RASMCs using aldosterone synthase (CYP11B2) specific primers, gave a single band of about 268 bp, consistent with that expected for the enzyme. Finally, using [(3)H]methylthymidine uptake as an index of cellular proliferation, tritium incorporation was increased in the AII-treated group at concentrations greater than 10(-10) M. The aldosterone antagonist, spironolactone (10(-5) M), inhibited the incorporation of [(3)H]thymidine into RASMCs stimulated by AII. These results suggest that locally generated aldosterone may mediate the effects of AII, acting via the AT1 receptor, in stimulating RASMC proliferation.

Evolutive changes of cellular proliferation index in atrophic gastritis after helicobacter pylori erradication

Evolutive changes of cellular proliferation index in atrophic gastritis after helicobacter pylori erradication