Troglitazone inhibits growth and improves insulin signaling by suppression of angiotensin II action in vascular smooth muscle cells from spontaneously hypertensive rats

Troglitazone, a thiazolizidinedione, has recently been reported to possess anti-arteriosclerotic properties. To evaluate mechanisms underlying the anti-arteriosclerotic effects of troglitazone, we examined the effect of troglitazone on growth, expression of growth factors, and insulin signaling in vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) which produce angiotensin II (Ang II) in a homogeneous culture. Troglitazone inhibited basal and serum-stimulated DNA synthesis and inhibited increases in the number of VSMC from SHR and normotensive Wistar-Kyoto (WKY) rats. Its inhibition was greater in VSMC from SHR. Troglitazone abolished DNA synthesis in response to Ang II in VSMC from both rat strains and markedly inhibited DNA synthesis in response to epidermal growth factor (EGF) and platelet-derived growth factor (PDGF)-AA in VSMC from SHR. Troglitazone did not alter the expression of transforming growth factor (TGF)-beta1, PDGF A-chain, or basic fibroblast growth factor (bFGF) mRNAs in VSMC from WKY rats, but it markedly decreased expression of these growth factor mRNAs in VSMC from SHR. Troglitazone markedly decreased basal and Ang II-stimulated expression of extracellular signal-regulated kinase proteins in VSMC from both rat strains. Troglitazone abolished Ang II-induced suppression of phosphatidilinositol 3-kinase (PI3-kinase) activity, insulin receptor substrate-1 (IRS-1) associated tyrosine phosphorylation, and IRS-1 associated p85 levels in VSMC from WKY rats. Basal PI3-kinase activity, tyrosine phosphorylation of IRS-1, and IRS-1 associated p85 levels were lower in VSMC from SHR than in cells from WKY rats. Troglitazone significantly increased PI3-kinase activity, IRS-1 associated tyrosine phosphorylation, and IRS-1 associated p85 levels in VSMC from SHR. These results indicate that troglitazone produce its anti-arteriosclerotic effects through suppression of the action of growth-promoting factors including Ang II, and that troglitazone inhibits Ang II-induced suppression of insulin signaling in VSMC from SHR, suggesting that tissue Ang II may lead to insulin resistance and to arteriosclerosis in hypertension. Troglitazone may be useful in the treatment of insulin resistance as well as of hypertensive vascular diseases.     

Leukocyte angiotensin II levels inpatients with essential hypertension:relation to insulin resistance

Insulin resistance is involved in the pathogenesis of type 2 diabetes, hypertension, and atherosclerosis. Angiotensin (Ang) converting enzyme inhibitors and Ang II type 1 receptor antagonists improve insulin resistance in patients with essential hypertension, which suggest that tissue Ang II is involved in insulin resistance in patients with hypertension. To investigate the participation of tissue Ang II in insulin resistance associated with hypertension, we evaluated the Ang II-generating system in leukocytes and its relation to insulin resistance in patients with essential hypertension. Eighteen patients with essential hypertension participated in this study. Ang II was separated from leukocytes by reversed-phase high-performance liquid chromatography and measured by radioimmunoassay. Insulin resistance was evaluated by determining the steady-state of plasma glucose (SSPG) concentration. The Ang I- and Ang II-generating activities were evaluated in human leukocytes. Human leukocytes have Ang I- and Ang II-generating activities. The Ang II-generating activity was significantly inhibited by pepstatin A. Leukocyte Ang II level does not correlate with BP or plasma Ang II level in patients with essential hypertension. Leukocyte Ang II level strongly correlates with SSPG concentration, and significantly correlates with body mass index and plasma insulin, and with leptin levels in patients with essential hypertension. Leukocyte Ang II may be directly associated with insulin resistance.     

Overexpression of matrix metalloproteinase-9 promotes intravascular thrombus formation in porcine coronary arteries in vivo

OBJECTIVE: Matrix metalloproteinases (MMPs) cause extracellular matrix degradation and may be involved in the rupture of atherosclerotic plaques by degrading fibrous cap, resulting in the intravascular thrombus formation. Here we examined whether local overexpression of MMP-9 alters the characteristics of arteriosclerotic vascular lesions and promotes thrombosis after balloon injury in porcine coronary arteries in vivo. METHODS AND RESULTS: Balloon angioplasty was performed in the left coronary arteries followed by injection of adenovirus vector solution encoding either MMP-9 or beta-galactosidase (beta-gal) gene into the injured coronary arteries. Three weeks after the gene transfer, histological examination demonstrated that macroscopic intravascular thrombus formation was noted at the MMP-9-transfected site but not at the beta-gal-transfected site. Microscopic intramural thrombus area was significantly larger at the MMP-9-transfected site as compared to the beta-gal-transfected site. Co-transfection of tissue inhibitor of metalloproteinase-1 (TIMP-1) with MMP-9 prevented the intravascular thrombus formation in vivo. Western blot analysis revealed the reduced expression of intact tissue factor pathway inhibitor-1 and the increased tissue factor (TF) expression at the MMP-9-transfected sites. CONCLUSION: These results provide the first in vivo evidence that overexpression of MMP-9 promotes intravascular thrombus formation after balloon injury due in part to the activation of TF-mediated coagulation cascade.     

A questionnaire-based survey on the etiopathogenesis of chronic constipation during a medical check-up in Japan

The study group of the Japanese Society of Gastroenterology released evidence-based clinical practice guidelines for chronic constipation (CC) in 2017, and irritable bowel syndrome (IBS) was treated as one of the causes of CC. We examined the differences in characteristics between IBS and non-IBS subjects with CC who underwent a medical check-up in Japan. A total of 10,658 subjects participated in this study, and we focused on 467 subjects who fulfilled the diagnostic criteria of CC using a questionnaire survey. The number of IBS subjects was 21, and they had sleep disorders, were more symptomatic (e.g., abdominal pain, abdominal bloating/distension, feeling stressed, annoyance, lack of motivation, fatigue upon waking, and feeling depressed), and had more episodes of sensation of incomplete evacuation and anorectal obstruction/blockage during defecation than non-IBS subjects. Furthermore, stool frequency of IBS subjects was significantly different from non-IBS subjects. Multivariate ordinal logistic regression analysis revealed that the factors associated with a higher stool frequency were IBS [odds ratio (OR), 2.46; 95% confidence interval (CI), 1.00–6.05; p = 0.049], male sex (OR, 1.97; 95% CI, 1.20–3.23; p = 0.007), and regular exercise (OR, 1.80; 95% CI, 1.05–3.07; p = 0.033). These findings suggest that IBS has unique characteristics in subjects with CC.     

Seven Years of Chronological Changes of Serum Chromium Levels After Metasul Metal-On-Metal Total Hip Arthroplasty

Although many authors have reported the serum concentrations of metal ions in patients who had metal-on-metal coupling prostheses, most of the studies were not longitudinal, and the follow-up periods were short. We evaluated the longitudinal changes of serum chromium levels in 44 patients who had undergone unilateral metal-on-metal total hip arthroplasty for a minimum of 7 years postoperatively. Although there was a consistent increase in the mean serum chromium level until 3 years after implantation, there was little difference in the levels from years 3 to 7 postoperatively. Although the serum chromium concentration was low throughout postoperative follow-up for 7 years in about 25% of patients, the serum chromium level stayed high or showed gradual elevation in 16.3% of our patients.     

Cross‐sectional analysis of germline BRCA1 and BRCA2 mutations in Japanese patients suspected to have hereditary breast/ovarian cancer

The prevalence of BRCA1/2 germline mutations in Japanese patients suspected to have hereditary breast/ovarian cancer was examined by a multi‐institutional study, aiming at the clinical application of total sequencing analysis and validation of assay sensitivity in Japanese people using a cross‐sectional approach based on genetic factors estimated from personal and family histories. One hundred and thirty‐five subjects were referred to the genetic counseling clinics and enrolled in the study. Full sequencing analysis of the BRCA1/2 gene showed 28 types of deleterious mutations in 36 subjects (26.7%), including 13 types of BRCA1 mutations in 17 subjects (12.6%) and 15 types of BRCA2 mutations in 19 subjects (14.1%). Subjects were classified into five groups and 22 subgroups according to their personal and family history of breast and/or ovarian cancer, and the prevalence of deleterious mutations was compared with previously reported data in non‐Ashkenazi individuals. Statistical analysis using the Mantel‐Haenszel test for groups I through IV revealed that the prevalence of Japanese subjects was significantly higher than that of non‐Ashkenazi individuals (P = 0.005, odds ratio 1.87, 95% confidence interval 1.22–2.88). Family history of the probands suffering from breast cancer indicated risk factors for the presence of deleterious mutations of BRCA1/2 as follows: (1) families with breast cancer before age 40 within second degree relatives (P = 0.0265, odds ratio 2.833, 95% confidence interval 1.165–7.136) and (2) families with bilateral breast cancer and/or ovarian cancer within second degree relatives (P = 0.0151, odds ratio 2.88, 95% confidence interval 1.25–6.64). (Cancer Sci 2008; 99: 1967–1976)     

Histological study on gland tissue in the median region of the lingual root--morphology of the foramen cecum and posterior lingual gland

The lingual root is an area where the thyroid gland develops and small salivary glands composed of both serous and mucous glands are distributed in the submucosa. In this paper the foramen cecum and mucous glands at the root of the tongue were histologically investigated in serial sagittal sections of the medial portion of the lingual root. The materials were obtained from 59 autopsied cases, excluding the cases with metabolic disease, brain tumor and neck tumor in whom the original disease might exert direct or indirect effects to the gland tissue. The frontal end was determined to be the line which connects the right and left palatoglossal arch junctions with the tongue, and the rear end the line of transition of the vallecula to the epiglottis. The specimen was cut in half along the median lingual sulcus and median glossoepiglottic fold. Each serial section of 4 microns in thickness was cut from the median plain to the lateral and stained with Hematoxylin-Eosin or Pas-Alcian blue at pH 2.5. The results of the study were summarized as follows. 1) The foramen cecum was histopathologically confirmed in 12 cases out of 59 (20%). The ratio of the detection did not show any difference between both sexes and in the groups of different age. 2) The mucous gland opening into the mucosal epithelium, which were located at the side of the lingual apex from the Ebner's gland or serous gland, were detected in 45 out of 59 (76%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fetal diaphragmatic hernia: prenatal evaluation of lung hypoplasia and effects of immediate operation

The outcome of fetuses with diaphragmatic hernia (CDH) has been reported to be related to the severity of lung hypoplasia. As an index of pulmonary hypoplasia, we attempted to measure the lung-thorax transverse area ratio (L/T) using ultrasonic echography in eight fetuses with left-sided CDH. Two cases with L/T more than 0.28 (controls: 0.52±0.04) were transported postnatally and recovered after early operation without episodes of persistent fetal circulation. Elective surgical repair was performed in six infants immediately after cesarean delivery at 35–37 weeks' gestation. In three cases with L/T between 0.21 and 0.24 who recovered with no complications, surgical reduction of the abdominal organs improved arterial blood gases and high-frequency oscillation ventilation (HFOV) was fully effective for respiratory management. In three with L/T between 0.11 and 0.17, extracorporeal membrane oxygenation (ECMO) was required from the 1st to the 12th postoperative day despite HFOV. Although two infants died of combined cardiovascular anomalies and airway bleeding caused by prolonged HFOV, respectively, one infant with minimal L/T survived. Measurement of L/T may help to predict the outcome of fetuses with CDH and to determine the indications for various treatments including immediate operation after cesarean delivery, HFOV, and ECMO. Offprint requests to: S. Kamata     

Adenovirus-mediated transfer of ribozyme targeting platelet-derived growth factor A-chain mRNA inhibits growth of vascular smooth muscle cells from spontaneously hypertensive rats

Platelet-derived growth factor (PDGF) is a potent stimulator of growth of vascular smooth muscle cells (VSMCs). VSMCs from spontaneously hypertensive rats (SHRs) show exaggerated growth and increasingly express PDGF A-chain messenger RNA (mRNA). To examine adenovirus-mediated transfer of a ribozyme targeting the PDGF A-chain mRNA as a possible gene therapy for vascular proliferative diseases, a recombinant adenovirus vector encoding a ribozyme that targets rat PDGF A-chain mRNA (Ad. ribozyme) was designed and synthesized and its effect on the growth of VSMCs from SHRs was investigated. This vector dose-dependently inhibited DNA synthesis in VMSCs from SHRs, whereas an adenovirus vector encoding the Escherichia coli LacZ gene (Ad. LacZ) did not affect DNA synthesis. Ad. ribozyme significantly suppressed proliferation of VSMCs from SHRs in a dose-dependent manner. Ad. LacZ had no effect. Ad. ribozyme significantly inhibited expression of PDGF A-chain mRNA and PDGF-AA protein in VSMCs from SHRs. Ad. LacZ had no effect. These results demonstrated that adenovirus-mediated transfer of a ribozyme targeting the PDGF A-chain mRNA effectively and specifically inhibited the growth of VSMCs from SHRs with suppression of PDGF A-chain mRNA and PDGF-AA protein expression. Adenovirus-mediated transfer of ribozyme targeting PDGF A-chain mRNA may be a feasible gene therapy for vascular proliferative diseases.