herbimycin and Hyperplasia

intimal hyperplasia (IH) is a major cause of re-stenosis post-vascular intervention. Induction of heat shock proteins (HSPs), by thermal pre-conditioning, reduces IH. Our aim was to investigate the effect of the pharmacological HSP inducer herbimycin A on IH in the rat carotid balloon injury model.. thirty male Sprague-Dawley rats were randomized into three groups. All groups underwent balloon injury to the left carotid artery. Stress proteins were induced 18 h pre-operatively by heat shock or herbimycin A. Two weeks post-operatively, animals were sacrificed and carotid intima/media area ratio (I/M ratio) calculated using computerized planimetry. Neo-intimal proliferation was assessed immunohistochemically with PCNA (proliferating cell nuclear antigen). Western blot and immunohistochemistry for arterial HSP70 and HSP27 were performed.. heat stress and herbimycin significantly reduced the I/M ratio (p < 0.05 vs balloon injury alone). Neo-intimal proliferation was significantly reduced in the heat stress and herbimycin groups (p < 0.05 vs balloon injury alone). Heat stress induced arterial HSP70 and HSP27. Herbimycin A increased arterial HSP27.. herbimycin A significantly attenuates IH after balloon injury. HSP27 may be the HSP involved in mediating this response. Pharmacological inducers of HSPs may have a therapeutic role to play in preventing re-stenosis post-vascular intervention.

Topics: Angioplasty, Balloon; Animals; Benzoquinones; Blotting, Western; Carotid Arteries; Carotid Artery Injuries; Enzyme Inhibitors; Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Hyperplasia; Immunohistochemistry; Ischemic Preconditioning; Lactams, Macrocyclic; Male; Models, Animal; Proliferating Cell Nuclear Antigen; Quinones; Random Allocation; Rats; Rats, Sprague-Dawley; Recurrence; Rifabutin; Tunica Intima

Increased intraluminal pressure of the rat portal vein in vivo causes hypertrophy and altered contractility in 1 to 7 days. We have used organ cultures to investigate mechanisms involved in this adaptation to mechanical load. Strips of rat portal vein were cultured for 3 days, either undistended or loaded by a weight. Length-force relations were shifted toward longer length in stretched cultured veins compared with freshly dissected veins, whereas the length-force relations of unstretched cultured veins were shifted in the opposite direction. This occurred after culture either with or without 10% FCS to promote growth. The wet weight of loaded veins increased by 56% in the presence of FCS, whereas that of undistended control veins increased by 24%. No weight increase was seen in serum-free culture. The dry/wet weight ratio decreased during culture with FCS but was not affected by stretch. Electron microscopy revealed increased cell cross-sectional area in stretched relative to unstretched veins, and protein contents were greater, as were [(3)H]thymidine and [(3)H]leucine incorporation rates. Growth responses were associated with the activation of stretch-sensitive extracellular signal-regulated kinases 1 and 2 and were inhibited by herbimycin A and PD 98059, inhibitors of extracellular signal-regulated kinases 1 and 2. The results demonstrate that by culture of whole vascular tissue, smooth muscle cells are maintained in the contractile phenotype and respond to stretch with a physiological adaptation involving hypertrophy/hyperplasia and remodeling of the contractile system, similar to that in vivo. Mechanical stimulation and growth factors are both required for functionally significant growth.

Topics: Animals; Benzoquinones; Cattle; Culture Media; Culture Media, Serum-Free; DNA Replication; Enzyme Activation; Enzyme Inhibitors; Female; Fetal Blood; Flavonoids; Hyperplasia; Hypertrophy; Lactams, Macrocyclic; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Muscle Contraction; Muscle Development; Muscle Proteins; Muscle, Smooth, Vascular; Neovascularization, Physiologic; Organ Culture Techniques; Organ Size; Phenotype; Portal Vein; Quinones; Rats; Rats, Sprague-Dawley; Rifabutin; Signal Transduction; Stress, Mechanical

The histological features of rheumatoid arthritis (RA) consist of overgrowth of synovial cells. Several growth factors that cause synovial hyperplasia have been identified in RA synovium. The basic-fibroblast growth factor (b-FGF), representing one of these growth factors, may play an important role in the pathogenesis of RA. We examined the b-FGF-mediated intracellular signal pathway involved in synovial cell growth. b-FGF-induced synovial cell growth was inhibited by protein tyrosine kinase (PTK) inhibitors, herbimycin A and genistein, but not by H7 that inhibits protein kinase C (PKC). Stimulation of synovial cells with b-FGF resulted in tyrosine phosphorylation of cellular proteins and MAP kinase activation. Our results also demonstrated that b-FGF-mediated activation of MAP kinase was inhibited by herbimycin A indicating that protein tyrosine kinase may be involved in the activation of MAP kinase in human synovial cells. However, inhibition of b-FGF-mediated MAP kinase activation by PKC downregulation did not occur.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Arthritis, Rheumatoid; Benzoquinones; Calcium-Calmodulin-Dependent Protein Kinases; Cell Cycle; Cell Division; Cells, Cultured; Fibroblast Growth Factor 2; Fibroblasts; Genistein; Humans; Hyperplasia; Isoflavones; Isoquinolines; Kinetics; Lactams, Macrocyclic; Piperazines; Protein Kinase C; Protein Kinases; Protein-Tyrosine Kinases; Quinones; Rifabutin; Signal Transduction; Synovial Membrane; Thymidine