Postangioplasty restenosis: a practical model in the porcine carotid artery

Transluminal coronary angioplasty is a routine therapeutic intervention in coronary heart disease. Despite the high rate of primary success, restenosis continues to be its major limitation. Porcine models have been considered to be the most adequate experimental models for studying restenosis. One limitation of porcine models is the need for radiological guidance and the expenses involved. The objective of the present study was to adapt an experimental model of angioplasty in the porcine carotid artery that does not require radiological equipment. Eight animals were used to develop the technique of balloon injury to the common carotid artery by dissection without radiological guidance. This technique was then employed in six other animals. Under anesthesia, the left common carotid artery was dissected and incised at the carotid sinus for insertion of an over-the-wire angioplasty balloon towards the aorta. Overstretch injury of the carotid artery was performed under direct visualization. After 30 days, the arteries were excised and pressure-fixated. Uninjured carotid arteries from 3 additional animals were used as controls. A decreased luminal area associated with intimal hyperplasia and medial reaction was observed in all injured arteries. Immunohistochemistry identified the intimal hyperplastic cells as smooth muscle cells. Computerized morphometry of the ballooned segments revealed the following mean areas: lumen 2.12 mm2 (± 1.09), intima 0.22 mm2 (± 0.08), media 3.47 mm2 (± 0.67), and adventitia 1.11 mm2 (± 0.34). Our experimental model of porcine carotid angioplasty without radiological guidance induced a vascular wall reaction and permitted the quantification of this response. This porcine model may facilitate the study of vascular injury and its response to pharmacological interventions

Histopathological diagnosis of intra- and extrahepatic neonatal cholestasis

The histopathology of the liver is fundamental for the differential diagnosis between intra- and extrahepatic causes of neonatal cholestasis. However, histopathological findings may overlap and there is disagreement among authors concerning those which could discriminate between intra- and extrahepatic cholestasis. Forty-six liver biopsies (35 wedge biopsies and 11 percutaneous biopsies) and one specimen from a postmortem examination, all from patients hospitalized for neonatal cholestasis in the Pediatrics Service of Hospital de Clínicas de Porto Alegre, were prospectively studied using a specially designed histopathological protocol. At least 4 of 5 different stains were used, and 46 hepatic histopathological variables related to the differential diagnosis of neonatal cholestasis were studied. The findings were scored for severity on a scale from 0 to 4. Sections which showed less than 3 portal spaces were excluded from the study. Sections were examined by a pathologist who was unaware of the final diagnosis of each case. Bile tract permeability was defined by scintigraphy of the bile ducts and operative cholangiography. The F test and discriminant analysis were used as statistical methods for the study of the hepatic histopathological variables. The chi-square method with Yates correction was used to relate the age of the patients on the date of the histopathological study to the discriminatory variables between intra- and extrahepatic cholestasis selected by the discriminant function test. The most valuable hepatic histopathological variables for the discrimination between intra- and extrahepatic cholestasis, in decreasing order of importance, were periportal ductal proliferation, portal ductal proliferation, portal expansion, cholestasis in neoductules, foci of myeloid metaplasia, and portal-portal bridges. The only variable which pointed to the diagnosis of intrahepatic cholestasis was myeloid metaplasia. Due to the small number of patients who were younger than 60 days on the date of the histopathological study (N = 6), no variable discriminated between intra- and extrahepatic cholestasis before the age of 2 months and all of them, except for the portal expansion, were discriminatory after this age. In infants with cholestasis, foci of myeloid metaplasia, whenever present in the liver biopsy, suggested intrahepatic cholestasis. Periportal ductal proliferation, portal ductal proliferation, portal expansion, cholestasis in neoductules, portal cholestasis and portal-portal bridges suggested extrahepatic obstructive cholestasis.

Induction of interleukin-10 by HIV antigens in peripheral mononuclear cells of health care workers after occupational exposure to HIV-1-positive blood

Evaluation of HIV-induced IL-2 production by peripheral blood mononuclear cells (PBMC) and HIV-specific T helper and cytotoxic T lymphocyte (CTL) responses in health care workers (HCW) occupationally exposed to HIV reveals a high rate of response to HIV among non-seroconverters. IL-10 is also known to interfere with HIV infection in vitro. To evaluate the induction of IL-10 by HIV antigens in HCW occupationally exposed to HIV, 18 HCW with percutaneous injury were enrolled in this study, 9 of them exposed to HIV-contaminated blood, and 9 exposed to HIV-negative blood. PBMC were incubated on plates coated with HIV-1 antigens, and IL-10 was measured in supernatants by ELISA. Five of nine HCW exposed to HIV-contaminated blood presented HIV-induced IL-10. Two of nine HCW exposed to HIV-negative source patients also had detectable levels of HIV-induced IL-10, one of them in the sample obtained on the day of accidental exposure. There was a relationship between the type of device involved in injury and IL-10 production. Individuals exposed to hollow needles or scalpels presented HIV-induced IL-10, whereas those exposed to solid needles and to digital puncture did not, suggesting a relationship between infectious load and IL-10. Although occupational exposure to HIV leads to a low rate of seroconversion, these individuals can develop an antigen-specific immune response characterized in our study by induction of IL-10 in PBMC in vitro.

Diagnosis, staging and treatment of hepatocellular carcinoma

Hepatocellular carcinomas are aggressive tumors with a high dissemination power. An early diagnosis of these tumors is of great importance in order to offer the possibility of curative treatment. For an early diagnosis, abdominal ultrasound and serum alpha-fetoprotein determinations at 6-month intervals are suggested for all patients with cirrhosis of the liver, since this disease is considered to be the main risk factor for the development of the neoplasia. Helicoidal computed tomography, magnetic resonance and/or hepatic arteriography are suggested for diagnostic confirmation and tumor staging. The need to obtain a fragment of the focal lesion for cytology and/or histology for a diagnosis of hepatocellular carcinoma depends on the inability of imaging methods to diagnose the lesion. Several classifications are currently available for tumor staging in order to determine patient prognosis. All take into consideration not only the stage of the tumor but also the degree of hepatocellular dysfunction, which is known to be the main factor related to patient survival. Classifications, however, fail to correlate treatment with prognosis and cannot suggest the ideal treatment for each tumor stage. The Barcelona Classification (BCLC) attempts to correlate tumor stage with treatment but requires prospective studies for validation. For single tumors smaller than 5 cm or up to three nodules smaller than 3 cm, surgical resection, liver transplantation and percutaneous treatment may offer good anti-tumoral results, as well as improved patient survival. Embolization or chemoembolization are therapeutic alternatives for patients who do not benefit from curative therapies.

Effect of oral sirolimus therapy on inflammatory biomarkers following coronary stenting

We studied the effect of oral sirolimus, administered to prevent and treat in-stent restenosis (ISR), on the variation of serum levels of inflammatory markers following coronary stenting with bare metal stents. The mean age of the patients was 56 ± 13 years, 65% were males and all had clinically manifested ischemia. Serum levels of high sensitivity C-reactive protein (hs-CRP) concentration were determined by chemiluminescence and serum levels of all other biomarkers by ELISA. One group of patients at high risk for ISR received a loading oral dose of 15 mg sirolimus and 5 mg daily thereafter for 28 days after stenting (SIR-G). A control group (CONT-G) was submitted to stenting without sirolimus therapy. The increase in hs-CRP concentration was highest at 24 h after stenting in both groups. A significant difference between SIR-G and CONT-G was observed at 4 weeks (-1.50 ± 5.0 vs -0.19 ± 0.4, P = 0.008) and lost significance 1 month after sirolimus discontinuation (-1.73 ± 4.3 vs -0.01 ± 0.7, P = 0.0975). A continuous fall in MMP-9 concentration was observed in SIR-G, with the greatest reduction at 4 weeks (-352.9 ± 455 vs +395.2 ± 377, P = 0.0004), while a positive variation was noted 4 weeks after sirolimus discontinuation (227 ± 708 vs 406.2 ± 472.1, P = 0.0958). SIR-G exhibited a higher increase in P-selectin after sirolimus discontinuation at week 8 (46.1 ± 67.9 vs 5.8 ± 23.7, P = 0.0025). These findings suggest that the anti-restenotic actions of systemic sirolimus include anti-proliferative effects and modulation of the inflammatory response with inhibition of adhesion molecule expression.

Experimental model of intervertebral disc degeneration by needle puncture in Wistar rats

Animal models of intervertebral disc degeneration play an important role in clarifying the physiopathological mechanisms and testing novel therapeutic strategies. The objective of the present study is to describe a simple animal model of disc degeneration involving Wistar rats to be used for research studies. Disc degeneration was confirmed and classified by radiography, magnetic resonance and histological evaluation. Adult male Wistar rats were anesthetized and submitted to percutaneous disc puncture with a 20-gauge needle on levels 6-7 and 8-9 of the coccygeal vertebrae. The needle was inserted into the discs guided by fluoroscopy and its tip was positioned crossing the nucleus pulposus up to the contralateral annulus fibrosus, rotated 360° twice, and held for 30 s. To grade the severity of intervertebral disc degeneration, we measured the intervertebral disc height from radiographic images 7 and 30 days after the injury, and the signal intensity T2-weighted magnetic resonance imaging. Histological analysis was performed with hematoxylin-eosin and collagen fiber orientation using picrosirius red staining and polarized light microscopy. Imaging and histological score analyses revealed significant disc degeneration both 7 and 30 days after the lesion, without deaths or systemic complications. Interobserver histological evaluation showed significant agreement. There was a significant positive correlation between histological score and intervertebral disc height 7 and 30 days after the lesion. We conclude that the tail disc puncture method using Wistar rats is a simple, cost-effective and reproducible model for inducing disc degeneration.

Preventive effect of reduced glutathione on contrast-induced nephropathy in elderly patients undergoing coronary angiography or intervention: a randomized, controlled trial

Coronary angiography can be a high-risk condition for the incidence of contrast-induced nephropathy (CIN) in elderly patients. Reduced glutathione, under a variety of mechanisms, may prevent CIN in this procedure. We prospectively examined whether hydration with reduced glutathione is superior to hydration alone for prevention of CIN in an elderly Han Chinese population. A total of 505 patients (271 males and 234 females) aged 75 years or older who underwent non-emergency coronary angiography or an intervention were randomly divided into two groups. The treatment group received hydration with reduced glutathione (n=262) and the control group received hydration alone (n=243). Serum creatinine and blood urea nitrogen levels were measured prior to coronary angiography and 48 h after this procedure. The primary endpoint was occurrence of CIN, which was defined as 25% or 44.2 µmol/L above baseline serum creatinine levels 48 h after the procedure. The overall incidence of CIN was 6.49% in the treatment group and 7.41% in the control group, with no significant difference between the groups (P=0.68). In subgroup analysis by percutaneous coronary intervention, no significant differences were found between the two groups. In summary, reduced glutathione added to optimal hydration does not further decrease the risk of CIN in elderly patients undergoing coronary angiography or an intervention.