Held still or pressured to receive dental treatment: self-reported histories of children and adolescents treated by non-specialist dentists in Hordaland, Norway.

AIM: This study aimed to estimate the prevalence of a self-reported history of restraint in children and adolescents when receiving dental care by non-specialist dentists and to assess differences in dental fear and anxiety (DFA), intra-oral injection fear, and trust in dentists between patients with and without a self-reported history of restraint. METHODS: An electronic cross-sectional survey was distributed to all 9 years old (n = 6686) and 17 years old (n = 6327) in the Public Dental Service in Hordaland County, Norway, in 2019. For statistical evaluation, we generated descriptive statistics and Mann-Whitney U tests. RESULTS: The response rate ranged between 43.5 and 59.9% for the different questions. The prevalence of a self-reported history of being held still against one's will during dental treatment and pressured to undergo dental treatment against one's will was 3.6% and 5.1%, respectively. In general, these patients reported higher DFA, and higher intra-oral injection fear compared with those without such histories of restraint. Patients who had reported being held still against their will during dental treatment had significantly higher distrust in dentists than those who did not report restraint (p < 0.001). CONCLUSION: To feel pressured to receive dental treatment and to be held still against one's will overlap with the concepts of psychological and physical restraint. Patients with a self-reported history of restraint recorded significant differences in DFA, intra-oral injection fear, and trust in dentists compared to those who did not report restraint. Future studies should explore the role that restraint may play in relation to a patient's DFA, intra-oral injection fear, and trust in dentists.

Patient-self-reported history of restraint among 17-year-olds: a retrospective study of records by non-specialist dentists in the public dental service in Hordaland, Norway.

PURPOSE: The primary purposes were to examine dental records of Norwegian adolescents' with and without self-reported history of restraint for information about oral health (DMFT), total scheduled time in the Public Dental Service (PDS) (dental appointments, cancelled and missed appointments), and reluctant behaviour and/or dental fear and anxiety (DFA). Another purpose was to explore their dental records for information recorded by the dentist concerning the use of restraint. METHODS: Data on patient-self-reported history of restraint and DFA were collected in a population-based cross-sectional survey of 17-year-olds in the PDS in Hordaland, Norway, 2019. Patients were divided into two groups: self-reported restraint group (N1 = 26) and self-reported non-restraint group (N2 = 200). Data on oral health and dental treatment, total scheduled time of the PDS, reluctant behaviour or DFA, and information on the use of restraint were extracted from the dental records written by non-specialist dentists using a pre-set protocol covering the period from 2002 to 2019. RESULTS: A total of 206 dental records were analysed. Adolescents with self-reported history of restraint (n1 = 18) had higher DMFT and greater descriptions of reluctant behaviour and/or DFA, and total scheduled time compared with the self-reported non-restraint group (n2 = 188). The use of restraint was recorded in the dental records of one patient from the self-reported restraint group and in two patients from the self-reported non-restraint group. CONCLUSIONS: The adolescents with self-reported history of restraint had higher DMFT, higher scheduled time attending the PDS, and had more descriptions of reluctant behaviour and/or signs of DFA compared with the self-reported non-restraint group. The patient records contained limited information concerning restraint, and there were significant discrepancies between patient-self-reported history of restraint and the recording of restraint by the dentist in the patients' records.

Erratum: Frequency of heavy vehicle traffic and association with DNA methylation at age 18 years in a subset of the Isle of Wight birth cohort.

[This corrects the article DOI: 10.1093/eep/dvy028.][This corrects the article DOI: 10.1093/eep/dvy028.].

Frequency of heavy vehicle traffic and association with DNA methylation at age 18 years in a subset of the Isle of Wight birth cohort.

Assessment of changes in DNA methylation (DNA-m) has the potential to identify adverse environmental exposures. To examine DNA-m among a subset of participants (n = 369) in the Isle of Wight birth cohort who reported variable near resident traffic frequencies. We used self-reported frequencies of heavy vehicles passing by the homes of study subjects as a proxy measure for TRAP, which were: never, seldom, 10 per day, 1-9 per hour and >10 per hour. Methylation of cytosine-phosphate-guanine (CpG) dinucleotide sequences in the DNA was assessed from blood samples collected at age 18 years (n = 369) in the F1 generation. We conducted an epigenome wide association study to examine CpGs related to the frequency of heavy vehicles passing by subjects' homes, and employed multiple linear regression models to assess potential associations. We repeated some of these analysis in the F2 generation (n = 140). Thirty-five CpG sites were associated with heavy vehicular traffic. After adjusting for confounders, we found 23 CpGs that were more methylated, and 11 CpGs that were less methylated with increasing heavy vehicular traffic frequency among all subjects. In the F2 generation, 2 of 31 CpGs were associated with traffic frequencies and the direction of the effect was the same as in the F1 subset while differential methylation of 7 of 31 CpG sites correlated with gene expression. Our findings reveal differences in DNA-m in participants who reported higher heavy vehicular traffic frequencies when compared to participants who reported lower frequencies.

Functional state of the respiratory and immune system in children-residents of the radioactive contaminated territories.

More then 25 years after the Chernobyl accident, a higher prevalence of bronchial hyperreactivity, reduced lung function, and increased levels of free radicals in exhaled breath condensates (EBC) were observed in children residing in radioactive contaminated territories. Comparing children with different residential radiation background, this study investigated fatty acids of EBC using gas liquid chromatography, counts of B-lymphocyte antigen CD19 in T-cell (CD3) and phagocytotic activity of neutrophils in blood samples. Regarding EBC, we demonstrate that lipid peroxidation was activated, antioxidant properties of pulmonary surfactant were decreased, were detected metabolic disorders of essential fatty acids at the stage of bioregulators-eicosanoids formation. Regarding the immune function of blood cells, we found a decrease of the proportions of CD3+ 19- and CD3- 19+ lymphocyte subpopulations and an unbalance of their numbers. Also the phagocytotic activity of neutrophils was reduced in higher exposed children. Children living in the radioactive contaminated territories have more alterations of surfactant properties and immune activities, which may contribute to an increased risk of respiratory problems. This research was supported by grants from the U.S. Civilian Research and Development Foundation (UKB1-2929-KV-08).

Sustained retention of tetradecylthioacetic acid after local delivery reduces angioplasty-induced coronary stenosis in the minipig.

OBJECTIVE: The sulfur containing tetradecylthioacetic acid (TTA) has a profound effect on lipid metabolism and may also exert antioxidant and anti-inflammatory actions and thereby counteract coronary stenosis after angioplasty balloon injury. This study examined the possible modulatory effects of TTA, delivered locally, on coronary stenosis in minipigs and the underlying mechanisms of action. METHODS: Coronary balloon angioplasty injury using an oversized balloon was performed to 40 coronary arteries (20 minipigs, Sus Scrofa, Gammelsroed) followed by delivery of placebo or TTA via a local drug delivery balloon catheter. TTA was radiolabelled in four pigs. Quantitative coronary angiography and intracoronary ultrasound (ICUS) were performed before and after injury, and after 4 weeks of follow-up. The arteries were examined with histomorphometry. The antioxidant and anti-inflammatory effects of TTA were examined on LDL oxidation and stimulated release of interleukin (IL)-2 and IL-10 in human peripheral blood mononuclear cells (PBMC), respectively. RESULTS: Radioactive TTA was present in the coronary wall after 4 weeks. Angiographic minimal luminal diameter (mean+/-S.E.M.) in the placebo and TTA group was 1.3+/-0.1 vs. 2.2+/-0.2 mm (P<0.01) at follow-up, stenosis rate was 55 and 20% (P<0.01). Remodeling was -0.56+/-0.12 in the TTA group and -1.28+/-0.09 in the placebo group (P<0.01). TTA significantly prolonged the lag time of LDL oxidation. In phytohemagglutinin stimulated PBMC, TTA significantly decreased IL-2 levels and increased IL-10 levels suggesting a marked anti-inflammatory net effect. CONCLUSIONS: Local delivery of TTA reduces coronary artery stenosis after PTCA as assessed by both angiographic, histomorphometric and ICUS examinations by influencing vessel remodeling rather than intimal hyperplasia. The underlying mechanism(s) seem to involve antioxidant and anti-inflammatory effects of this fatty acid analogue.

Tetradecylthioacetic acid reduces stenosis development after balloon angioplasty injury of rabbit iliac arteries.

BACKGROUND: tetradecylthioacetic acid (TTA) is a synthetic long-chain fatty acid analogue that inhibits the oxidative modification of low-density lipoprotein particles in vitro. We examined the influence of TTA on the arterial wall response after balloon angioplasty injury in a rabbit iliac model. METHODS AND RESULTS: 14 rabbits were randomized to receiving either TTA fatty acids 800 mg daily perorally (weight 3.6+/-0.1 kg) or to normal diet (weight 3.5+/-0.5 kg, P=NS). Angioplasty was performed via right carotidotomy on both iliac arteries using an oversized balloon catheter, the TTA group being pretreated for 3 weeks. After angioplasty, the lumen diameter was 2.37+/-0.18 versus 2.36+/-0.13 mm for the TTA and control groups, respectively (P=NS). At 10 weeks follow-up angiography, minimal luminal diameter was 1.64+/-0.27 versus 1.13+/-0.52 mm for the TTA and control groups respectively (P<0.05). Histomorphometry did not show significant differences in intimal hyperplasia between the two groups (maximal intimal thickness 0.22+/-0.04 versus 0.19+/-0.10 mm, P=NS and intimal area 0.32+/-0.12 versus 0.36+/-0.23 mm(2), P=NS for the TTA and the control groups, respectively). In the heart, the sum of the n-3 fatty acids was 8.9+/-2.7 in the TTA group versus 4.3+/-0.2 mol% in the control group (P<0.05). The anti-inflammatory fatty acid index, calculated as (22:5 n-3+22:6 n-3+20:3 n-6)/20:4 n-6, was 0.76+/-0.10 vs. 0.25+/-0.03 for the TTA and control groups, respectively (P<0.05). In vitro TTA (100 microM) reduced the proliferation of human smooth muscle cell by more than 50%. CONCLUSION: treatment with TTA is associated with positive arterial remodeling after angioplasty injury. The significance of the in vitro inhibition of human smooth muscle cell proliferation needs to be further elucidated.

Dietary intake and serum concentrations of antioxidants in children with juvenile arthritis.

OBJECTIVE: Earlier studies have shown that patients suffering from juvenile arthritis (JA) have reduced serum concentrations of antioxidants compared with healthy controls. The aim of this study was to investigate whether the lower serum concentration of antioxidants found in these patients could be explained by a low dietary intake. METHODS: Serum from 14 patients and 22 healthy controls was analysed for the antioxidants retinol, beta-carotene, vitamin E, zinc and selenium. All of the participants completed a food frequency questionnaire that gave a picture of their dietary intake for the previous month. RESULTS: Compared with the healthy controls, the patients with JA had significantly reduced serum concentrations of beta-carotene (0.57 +/- 0.41 and 0.71 +/- 0.26 mmol/L respectively, p < 0.05), retinol (918 +/- 246 and 1176 +/- 300 IE/L, respectively, p < 0.01) and zinc (12.7 +/- 2.6 and 13.3 +/- 1.2 mmol/L, respectively, p < 0.05). The dietary intake was equivalent in the two groups, but the dietary intake of vitamin A, vitamin E and zinc did not reach the recommended dietary allowances. There was a statistically significant difference in serum concentrations of vitamin E and selenium between patients regularly taking a dietary supplements and patients who did not do so (p < 0.05). This difference was not found in the control group. CONCLUSION: The results of this study confirm that children suffering from JCA have reduced serum levels of beta-carotene, retinol and zinc compared with healthy controls. Patients benefited from dietary supplements of nutrients when the dietary intake did not reach the recommended dietary allowances.

Combination therapy of cholesterol reduction and L-arginine supplementation controls accelerated vein graft atheroma.

Hyperlipidemia contributes to the development of intimal hyperplasia and accelerated atheroma in vein bypass grafts. Dietary cholesterol reduction and oral supplementation with L-arginine have been shown to reduce accelerated atheroma in experimental vein grafts. This study extends these observations by examining the effect of the combination therapy of cholesterol reduction and L-arginine supplementation on the development of intimal hyperplasia in vein grafts in hypercholesterolemic animals. Thirty New Zealand White rabbits had a carotid vein bypass graft performed and were sacrificed at 28 days postoperatively either for morphology (light and electron microscopy) and videomorphometry, or for in vitro contractile studies. Twenty animals received a 1% cholesterol diet for 4 weeks prior to surgery. This diet was continued until harvest in ten animals. Ten cholesterol-fed animals received L-arginine supplementation (2 g/kg/day, p.o.) for 7 days preoperatively and thereafter until harvest and in addition were returned to a normal diet on the day of surgery. The last ten animals were controls (normal diet). Combined cholesterol reduction and L-arginine supplementation prevented accelerated atheroma in vein grafts, halted the change in enhanced smooth muscle cell contractility, and improved endothelial cell function. Early postoperative therapy targeting atheroma development in the high-risk patient could offer significant morphological and functional benefits.

Early morphology of accelerated vein graft atheroma in experimental vein grafts.

Vein grafts fail because of the development of intimal hyperplasia and atheroma. Recent experimental evidence suggests that the presence of hypercholesterolemia induces a three-fold increase in intimal hyperplasia with early atheroma development within 4 weeks of implantation. We have previously demonstrated endothelial cell preservation and a short-lived (3-day) polymorphonuclear leukocyte infiltrate in vein grafts. The aim of this study is to define the early morphology and ultrastructure of vein grafts implanted into a hyperlipidemic environment to provide a pathological foundation on which to examine the cellular and molecular events that determine this accelerated response. Twenty-one male New Zealand White rabbits underwent a right carotid interposition bypass graft using the ipsilateral external jugular vein; all animals received a 1% cholesterol diet for 4 weeks prior to surgery and continuing postoperatively until harvest. Animals (n = 3 per time point) were sacrificed at 60 min, 1 day, 3 days, 5 days, 7 days, 14 days, and 28 days postoperatively for scanning and transmission electron microscopy of the vein grafts. No concurrent controls were employed. The results of this study suggest that in the presence of hypercholesterolemia, the pathophysiological processes involved in the vein graft are similar to those reported for noncholesterol-fed animals. There is a sustained subendothelial response with the prolonged presence of macrophages and cellular debris and the accumulation of foam cells.

Controlling transplant vasculopathy in cryopreserved vein grafts with polyethylene glycol and glutathione during transport.

BACKGROUND: the biological characteristics of cryopreserved allografts are poorly understood, although many factors are known to influence their outcome. This study examines the development of transplant vasculopathy in both fresh and cryopreserved vein allografts and specifically assesses the efficacy of a transport solution containing 10% polyethylene glycol and 10 microM glutathione (PEG/GSH). METHODS: jugular veins were harvested from control donor rabbits and transplanted as interposition carotid bypass grafts in 30 New Zealand White (NZW) rabbits. Ten received the fresh jugular veins (fresh). Ten animals received jugular veins which had been harvested, transported in a physiological solution, cryopreserved and stored in a standard fashion (cryopreserved). Ten animals received jugular veins which had been harvested, transported in the same solution with the addition of PEG/GSH, cryopreserved and stored in a standard fashion (PEG/GSH). Cryopreserved jugular veins were stored for 6 weeks before transplantation. All animals were sacrificed 28 days postoperatively. Vein grafts were perfusion-fixed and wall dimensions were determined by planimetry. RESULTS: all transplanted grafts were patent at harvest. The control cryopreserved vein grafts showed a 54% increase in mean intimal thickness (63+/-10 micron vs. 41+/-3 micron p<0.05) but no change in mean medial thickness (125+/-9 micron vs. 119+/-13 micron; p = N.S. ) compared to the fresh allograft. Transport of the grafts in PEG/GSH solution resulted in the abolition of the increase in intimal thickness (41+/-4 micron; p <0.01) associated with cryopreservation without a change in medial thickness (140+/-15 micron; p = N.S.) compared to the cryopreserved allograft. CONCLUSION: cryopreserved vein grafts develop significant intimal hyperplasia compared to freshly transplanted grafts. The use of PEG/GSH in the transport solution significantly reduces this transplant graft intimal hyperplasia to that which develops in fresh grafts and may lead to improvements in the clinical use of cryopreserved veins.

Alterations in wall tension and shear stress modulate tyrosine kinase signaling and wall remodeling in experimental vein grafts.

PURPOSE: Hemodynamic alterations have been implicated as major stimuli for the development of intimal hyperplasia in vein grafts that are implanted in the arterial circulation. Tyrosine kinase is known to mediate cell signaling. However, its role with in vivo mechanotransduction is not yet well defined. We used a novel bioprosthetic collagen tube to provide an external support to vein grafts and examined the subsequent changes in hemodynamics, tyrosine kinase signaling, wall remodeling, and vasomotor function. METHODS: Carotid interposition bypass grafting was performed with the reversed jugular vein in New Zealand white rabbits. In the experimental group (n = 15), after the completion of the proximal anastomosis, the vein was passed through a 4-mm collagen tube and the distal anastomosis was performed. The tube support was fashioned to completely cover the vein grafts. The control animals (n = 14) had no tube support. After surgery, the blood pressure and flow rate were measured and the wall tension and shear stress were calculated in the vein grafts on day 3 or day 28 (n = 5 per group). Tyrosine phosphorylation was assessed with the Western blot test in vein grafts at day 3 (n = 4 per group). The intimal and medial dimensions of the vein grafts were assessed with videomorphometry on day 28 (n = 5 per group). The cumulative dose response curves of the vein grafts to contractile and relaxant agonists were determined in isometric tension studies on day 28 (n = 5 per group). RESULTS: The use of tube support reduced wall tension 1.7-fold (P <.01) and increased shear stress 4.8-fold (P <.001) without altering the flow rate or blood pressure. The tyrosine kinase activity was reduced 15-fold (P <.001) in the tube-supported vein grafts. The intimal thickness was reduced by 45% in the tube-supported vein grafts as compared with the control grafts (46 +/- 2 mm vs 84 +/- 5 mm, respectively; P <.0001), and the media thickness was reduced by 20% (63 +/- 8 mm vs 79 +/- 4 mm, respectively; P <.05). Isometric tension studies showed preservation of contractile function and modulation of endothelial-dependent dysfunctional relaxation in tube-supported vein grafts. CONCLUSION: These results show that reduced wall tension and increased shear stress with an external tube support can effectively modulate the signaling, functional, and hyperplastic responses in vein grafts. We conclude that this simple strategy deserves further study and clinical consideration.

Time course of the regression of intimal hyperplasia in experimental vein grafts.

A previous study in which vein grafts were removed from the arterial circulation and reimplanted into the venous circulation of the same animal demonstrated regression of vein graft intimal hyperplasia and medial thickening within 14 days. The present study was designed to characterize the kinetics of the morphological and ultrastructural changes over this 14-day period. Twenty-one male New Zealand White rabbits received a reversed vein interposition bypass graft of the right common carotid artery. Fourteen days after the procedure, 21 vein grafts were isolated, removed, and reimplanted into the contralateral external jugular venous system as veno-venous interposition bypass grafts (reversal grafts). The grafts were harvested at 60 minutes, 1 day, 3 days, 5 days, 7 days, and 14 days after reversal. Before insertion into the venous circulation, the vein graft had a confluent endothelial cell surface with multiple layers of smooth muscle cells representing intimal hyperplasia. After 1 hour, the reversal graft retained an intact endothelial cell layer with no evidence of tissue edema or cellular disruption. By 24 hours, there were a few blood cells on the endothelial cell surface. There was no inflammatory infiltrate seen in the subendothelium, and the smooth muscle cells were unaltered. At 3 days, the endothelial cell lining remained intact with no polymorphonucleocytes in the subendothelium or within the graft wall. Underlying smooth muscle cells at this time were noted to contain cytoplasmic vacuoles. At 5 days, there were no inflammatory cells seen on the surface or within the vein graft wall, but many of the underlying smooth muscle cells within the intimal hyperplasia were noted to be fragmented and to have clumping of chromatin. After 7 days, the endothelial cells remained intact and there was widespread evidence of apoptosis beneath the subendothelium with highly fragmented smooth muscle cells, some of which were histologically in the process of breaking up. At 14 days, the grafts retained uniform endothelial cell surfaces. Most of the smooth muscle cells that composed the intimal hyperplasia seen before implantation as a reversal graft were gone. Areas of newly laid down collagen could be observed. There were no acute inflammatory cells but for some mast cells seen in the graft wall. This study demonstrates that in this model, regression of intimal hyperplasia was associated with apoptosis of the smooth muscle cells and the deposition of collagen. There was no evidence that this process is mediated by an acute inflammatory response. Regression therefore appears to be due to induction of smooth muscle cell apoptosis by either a reduction in pressure or flow or a combination of both factors. The findings will enable a systematic cellular and molecular analysis of the biology of regression, which may afford clues to better understand the biology of the developing intimal hyperplasia.

Locally applied antisense oligonucleotide to proliferating cell nuclear antigen inhibits intimal thickening in experimental vein grafts.

This study examines the effect of antisense oligonucleotide to proliferating cell nuclear antigen (PCNA) on the formation of vein graft intimal hyperplasia in vivo, using localized administration. Twenty-four New Zealand white rabbits had a right carotid interposition bypass graft using the external jugular vein and were sacrificed on the 28th postoperative day. To determine the effect of PCNA on the development of intimal hyperplasia, 6 animals had their grafts coated with a pluronic gel containing 18 base antisense oligonucleotide to PCNA (1 mg/ml), 6 received a pluronic gel containing an 18 base nonsense oligonucleotide (1 mg/ml), and 12 animals were controls (6 with and 6 without pluronic gel). These grafts were harvested for morphology and videomorphometry. There was no change in the intimal thickness between the control and gel-treated groups. (70 +/- 4 microm versus 72 +/- 4 microm; mean +/- s.e.m.; p = ns). The presence of nonsense oligonucleotide had no further effect. Antisense PCNA produced a 26% decrease in intimal thickness to 50 +/- 4 microm in the treated vein grafts (p < 0.03) without a change in medial thickness. This study shows that a local single application of antisense oligonucleotide to PCNA will reduce the intimal hyperplasia in experimental vein grafts over 28 days.

Local inhibition of tyrosine kinase activity markedly attenuates the development of intimal hyperplasia in experimental vein grafts.

BACKGROUND: Intimal hyperplasia is due to the migration and proliferation of vascular smooth muscle cells after bypass surgery. Tyrosine kinases are involved in many signal transduction pathways including cell proliferation. This study examines the effects of local treatment with the tyrosine kinase inhibitor, tyrphostin AG-51, on the formation of intimal hyperplasia in vein grafts. MATERIALS AND METHODS: Thirty-nine New Zealand White rabbits underwent interposition bypass grafting of the carotid artery using the jugular vein. In the first group (TKI), tyrphostin AG-51 (5 mg), dissolved in 600 microliter of dimethyl sulfoxide and Ringer's lactate (2:1, v:v), was used to incubate the veins ex vivo prior to grafting and delivered locally in 2.5 ml of 30% pluronic gel after grafting. The second group (DMSO) received the same treatment but without tyrphostin. In the third group (control), tyrphostin and DMSO were omitted from the incubation and gel delivery solutions. Postoperatively, vein grafts were harvested on Day 3 for Western analysis using an antiphosphotyrosine antibody (PY-20) to assess for tyrosine kinase activity, and on Day 28 for either morphologic or contractile function studies. RESULTS: Local application of the TKI to vein grafts resulted in a 49% reduction in intimal hyperplasia compared to DMSO-treated vein grafts (31 +/- 4 micrometer vs. 61 +/- 5 micrometer, P < 0.01). Treatment with DMSO alone reduced intimal hyperplasia by 28% compared to control (85 +/- 4 micrometer, P < 0.05). The contractile responses in the DMSO and TKI-treated vein grafts were equivalent. Western analysis showed a 39-fold decrease in tyrosine phosphorylation with TKI treatment compared to control. CONCLUSION: This study demonstrates that local short-term treatment with TKI produces a 49% reduction in intimal hyperplasia and suggests that phosphorylation of tyrosine residues is involved in the signaling pathways leading to the development of intimal hyperplasia in vein grafts.

Adenoviral-mediated inhibition of G beta gamma signaling limits the hyperplastic response in experimental vein grafts.

BACKGROUND: Vein graft intimal hyperplasia is associated with changes in G protein expression. The carboxyl terminus of the beta-adrenergic receptor kinase-1 (beta ARKCT) is known to inhibit G beta gamma-mediated mitogen-activated signaling pathways. This study examines the effects of adenoviral-mediated beta ARKCT infection on the development of intimal hyperplasia in vein grafts. METHODS: New Zealand White rabbits underwent bypass grafting of the carotid artery with the jugular vein. Vein grafts were infected with adenoviral vectors encoding for beta ARKCT (n = 19), beta-galactosidase (n = 3), or empty viral constructs (n = 12). In control animals, vein grafting was performed without infection (n = 10). RESULTS: The efficacy of beta ARKCT infection in vein grafts was verified by reverse transcriptase-polymerase chain reaction. X-gal staining of beta-galactosidase-infected vein grafts demonstrated the transgene in cells throughout the vessel wall. Adenoviral infection of vein grafts without gene transfer did not alter wall thicknesses or sensitivities to contractile agonists, compared with control grafts. beta ARKCT infection, however, reduced intimal thickness by 36% (P < .001) and medial thickness by 24% (P < .001), compared with empty viral infection. beta ARKCT-infected vein grafts also demonstrated increased sensitivity in response to contractile agonists. CONCLUSIONS: These results show that inhibition of G beta gamma signaling with adenoviral-mediated beta ARKCT in vivo infection effectively modifies the structural and functional hyperplastic abnormalities in vein grafts.

G protein signaling and vein graft intimal hyperplasia: reduction of intimal hyperplasia in vein grafts by a Gbetagamma inhibitor suggests a major role of G protein signaling in lesion development.

Vein grafting results in the development of intimal hyperplasia with accompanying changes in guanine nucleotide-binding (G) protein expression and function. Several serum mitogens that act through G protein-coupled receptors, such as lysophosphatidic acid, stimulate proliferative pathways that are dependent on the G protein betagamma subunit (Gbetagamma)-mediated activation of p21ras. This study examines the role of Gbetagamma signaling in intimal hyperplasia by targeting a gene encoding a specific Gbetagamma inhibitor in an experimental rabbit vein graft model. This inhibitor, the carboxyl terminus of the beta-adrenergic receptor kinase (betaARK(CT)), contains a Gbetagamma-binding domain. Vein graft intimal hyperplasia was significantly reduced by 37% (P<0.01), and physiological studies demonstrated that the normal alterations in G protein coupling phenotypically seen in this model were blocked by betaARK(CT) treatment. Thus, it appears that Gbetagamma-mediated pathways play a major role in intimal hyperplasia and that targeting inhibitors of Gbetagamma signaling offers novel intraoperative therapeutic modalities to inhibit the development of vein graft intimal hyperplasia and subsequent vein graft failure.

Local effects of nitric oxide supplementation and suppression in the development of intimal hyperplasia in experimental vein grafts.

OBJECTIVES: The universal response of vein grafts after insertion into the arterial circulation is the development of intimal hyperplasia; smooth muscle cell proliferation and connective tissue deposition, which may be modulated in part by dysfunctional endothelial nitric oxide (NO) metabolism. This study examines the effects of single dose, local application by pluronic gel of a NO donor, S-nitroso-N-acetylpenicillamine (SNAP) and an NO synthase inhibitor nitro-L-arginine methyl ester (L-NAME) on the formation of intimal hyperplasia. MATERIALS: Forty New Zealand white rabbits underwent jugular vein interposition grafting of the common carotid artery. DESIGN: Ten animals were controls, 10 animals had the outer surface of the vein graft coated with 30% pluronic gel (2.5 ml), and 10 each were immersed for 15 min prior to insertion in Ringer lactate containing 10(-3) M of SNAP or L-NAME and then had their vein grafts coated with 2.5 ml of gel containing either SNAP (10(-3) M) or L-NAME (10(-3) M), which allows for sustained delivery for up to 6 h. On the 28th post operative day, the animals were sacrificed and vein grafts were harvested for morphology by electron microscopy (SEM and TEM) and dimensional analysis by videomorphometry. RESULTS: All vein grafts developed intimal hyperplasia. On SEM the vein grafts had a confluent layer of endothelial cells with multiple layers of smooth muscle cells representing intimal hyperplasia in TEM. There were no demonstrable morphological differences between the four groups. Local treatment with SNAP produced a significant 36% decrease in mean intimal thickness (72 +/- 4 microns vs. 45 +/- 4 microns; mean +/- S.E.M.; p < 0.01) without a change in medial thickness compared to gel-only treated groups (58 +/- 6 microns vs. 61 +/- 7 microns; p = ns). Inhibition of NO synthase by L-NAME had no effect on the development of intimal hyperplasia (72 +/- 4 microns vs. 79 +/- 10 microns; p = ns); medial thickness was also unchanged. CONCLUSION: These data confirm the protective effect of NO in vascular injury and suggest that NO synthase activity is either absent or reduced to such a level that further inhibition in this short time course is not relevant to the pathophysiology of vein graft intimal hyperplasia.

Localized versus systemic angiotensin II receptor inhibition of intimal hyperplasia in experimental vein grafts by the specific angiotensin II receptor inhibitor L158,809.

BACKGROUND: This study examines the effect of the angiotensin II receptor (type 1) antagonist (L158,809) on the formation of vein graft intimal hyperplasia in vivo, by both localized and systemic administration. METHODS: Forty New Zealand White rabbits underwent carotid interposition bypass grafting with the external jugular vein and were killed on postoperative day 28. To determine the effect of L158,809 on the development of intimal hyperplasia, 10 animals received long-term oral therapy with L158,809 (10 mg/kg/day, begun 5 days before operation and continued until harvest), 10 animals underwent coating of the grafts with a pluronic gel containing L158,809 (10(-5) mol/L), and 20 animals were controls (10 with and 10 without pluronic gel). These grafts were harvested for either histologic analysis (n = 6 per group) or in vitro isometric tension studies to angiotensin II (n = 4 per group). RESULTS: Long-term oral treatment with L158,809 produced a 43% decrease in intimal thickness from 76 +/- 6 microns (mean +/- SEM) in the control animals to 43 +/- 7 microns in the treated vein grafts (p = 0.002). There was also a significant decrease (44%) in the medial thicknesses between the control (75 +/- 4 microns) and L158,809-treated (42 +/- 6 microns) vein grafts (p = 0.007). The contractile responses to angiotensin II were abolished in the vein grafts by long-term L158,809 therapy. Local application by gel of L158,809 produced a significant decrease (33%) in the intimal thickness (48 +/- 3 microns) but no change in medical thicknesses (76 +/- 6 microns) compared with control grafts. The contractile responses to angiotensin II were unchanged in the vein grafts by local L158,809 therapy. CONCLUSIONS: This study shows that a local single application of L158,809 will reduce the intimal response but not the medial response in vein grafts, whereas long-term treatment will reduce intimal hyperplasia and the medial response in experimental vein grafts. Therefore angiotensin II acting through AT1 receptors mediates a significant part of the intimal hyperplastic response in vein grafts that appears to involve two phases: an acute intimal response requiring short-term therapy and a long-term medial response that requires prolonged therapy.

Functional and histological differences in autogenous and allogenic vein grafts: two different vasculopathies?

The long-term biological characteristics and the functional and morphological changes that occur in fresh allografts are poorly understood. This study tests the hypothesis that the development of intimal hyperplasia and its associated functional changes are accelerated in an allograft compared to an autograft due to the additional immunological stimuli. Common carotid vein bypass grafts were performed in 40 New Zealand White rabbits: 20 received their ipsilateral jugular veins (autologous) and 20 received the fresh contralateral jugular veins from the control rabbit (allogenic). Electron microscopy was performed and intimal and medial dimensions were determined by videoplanimetry at 7, 14, and 28 days. Contraction and relaxation studies to a panel of agonists were also performed. The EC50's (agonist concentration which produces 50% of the maximal response) were calculated. All grafts remained patent. Allografts showed a 51% decrease in overall mean intimal thickness (41 +/- 3 microns vs. 83 +/- 12 microns; P < 0.01) and a 97% increase in overall mean medial thickness (140 +/- 15 microns vs. 71 +/- 3 microns; P < 0.01) compared to the autografts. The lumen of the allogenic vein grafts was equivalent to the autologous vein grafts. Overall mean total wall thickness only increased by 17%, 181 microns vs. 154 microns for allo- and autografts, respectively. The EC50 for norepinephrine, histamine, and bradykinin were similar in the auto- and allografts, while the EC50 to serotonin was significantly less in the allografts than in the autografts. Neither the precontracted auto- or allografts relaxed to acetylcholine or serotonin (receptor mediated, endothelium dependent). The EC50 for calcium ionophore (nonreceptor mediated, endothelium dependent) was equivalent in the auto- and allografts. The EC50 for the sodium nitroprusside-induced relaxation (endothelium independent) was significantly higher in the allograft than in the autograft. This study demonstrates that there are two different vasculopathies occurring in autografts and allografts: intimal hyperplasia is predominant in the autograft while an exaggerated medial response is predominant in the allograft. Serotonin contractility and endothelial-independent relaxation are enhanced in the allograft compared to the autograft.