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1.
Am J Transplant ; 13(6): 1576-85, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23601186

ABSTRACT

Postkidney transplant hyperparathyroidism is a significant problem. Vitamin D receptor agonists are known to suppress parathyroid hormone (PTH) secretion. We examined the effect of oral paricalcitol on posttransplant secondary hyperparathyroidism by conducting an open label randomized trial in which 100 incident kidney transplant recipients were randomized 1:1 to receive oral paricalcitol, 2 µg per day, for the first year posttransplant or no additional therapy. Serial measurements of serum PTH, calcium and bone alkaline phosphatase, 24-h urine calcium and bone density were performed. The primary endpoint was the frequency of hyperparathyroidism 1-year posttransplant. Eighty-seven patients completed the trial. One-year posttransplant, 29% of paricalcitol-treated subjects had hyperparathyroidism compared with 63% of untreated patients (p = 0.0005). Calcium supplementation was discontinued in two control and 15 treatment patients due to mild hypercalcemia or hypercalcuria. Paricalcitol was discontinued in four patients due to hypercalcuria/hypercalcemia and in one for preference. Two subjects required decreasing the dose of paricalcitol to 1 µg daily. Hypercalcemia was asymptomatic and reversible. Incidence of acute rejection, BK nephropathy and renal function at 1 year were similar between groups. Moderate renal allograft fibrosis was reduced in treated patients. Oral paricalcitol is effective in decreasing posttransplant hyperparathyroidism and may have beneficial effects on renal allograft histology.


Subject(s)
Ergocalciferols/administration & dosage , Hyperparathyroidism, Secondary/prevention & control , Kidney Transplantation/adverse effects , Administration, Oral , Bone Density Conservation Agents , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Humans , Hyperparathyroidism, Secondary/epidemiology , Hyperparathyroidism, Secondary/etiology , Male , Middle Aged , Minnesota/epidemiology , Prevalence , Prospective Studies , Treatment Outcome
2.
Am J Nephrol ; 36(6): 554-60, 2012.
Article in English | MEDLINE | ID: mdl-23221061

ABSTRACT

BACKGROUND: The nephrotic syndrome is associated with an increased risk of venous and arterial thrombosis. There are little published data on the distribution, interpretation or determinants of serum D-dimer levels in patients with the nephrotic syndrome. We aimed to describe this relationship. METHODS: This was a cross-sectional study of 100 patients with the nephrotic syndrome. Multivariate linear regression was used to evaluate for independent predictors of elevated D-dimer levels. Patients were observed for a period of 2 years after the baseline measurement of D-dimer level to assess for subsequent clinically evident thrombosis. RESULTS: On univariate linear regression, D-dimer elevation was associated with age in years ß (95% CI) 0.02 (0.016, 0.03), log-transformed urinary protein:creatinine ratio in g/g 0.439 (0.32, 0.558) and inversely with serum albumin in g/l -0.05 (-0.073, -0.035) and estimated glomerular filtration rate (eGFR) in ml/min/1.73 m(2) -0.01 (-0.016, -0.003). On multivariate linear regression, age in years ß (95% CI) 0.019 (0.012, 0.026), serum albumin in g/l -0.023 (-0.043, -0.003), and log-transformed urinary protein:creatinine ratio in g/g 0.266 (0.124, 0.408) were independently associated with elevated D-dimer levels. CONCLUSION: D-dimer levels are commonly raised in the nephrotic syndrome in the absence of clinically evident thrombosis, and are independently associated with age, degree of proteinuria and serum albumin, but not with eGFR. Baseline levels of D-dimer did not predict subsequent episodes of clinically evident thrombosis after 2 years of follow-up.


Subject(s)
Albuminuria/blood , Fibrin Fibrinogen Degradation Products/metabolism , Nephrotic Syndrome/blood , Adult , Age Factors , Aged , Creatinine/urine , Cross-Sectional Studies , Female , Glomerular Filtration Rate , Humans , Linear Models , Male , Middle Aged , Multivariate Analysis , Nephrotic Syndrome/urine , Proteinuria/blood , Serum Albumin/metabolism
3.
Transplant Proc ; 43(9): 3296-8, 2011 Nov.
Article in English | MEDLINE | ID: mdl-22099781

ABSTRACT

Necrobiosis lipoidica diabeticorum (NLD) is an inflammatory skin disorder of unknown cause which can be seen in patients with diabetes mellitus. Various treatments, including immunosuppressive agents have been tried, without consistent efficacy. NLD is generally thought not to correlate well with tight diabetic control. Pancreas transplantation is the only widely and clinically used treatment that restores euglycemia in type I diabetic recipients. We report a case of resolution of NLD that had been unchanged for decades before pancreas after kidney transplantation. Another unique aspect of our case was that immunosuppression was discounted as a confounding factor, because the patient had been exposed to the same antirejection regimen for 3 years preceding the pancreas transplantation.


Subject(s)
Necrobiosis Lipoidica/therapy , Pancreas Transplantation/methods , Blood Glucose/metabolism , Diabetes Complications/therapy , Diabetes Mellitus, Type 1/therapy , Female , Humans , Immunosuppressive Agents/therapeutic use , Inflammation , Kidney Transplantation/methods , Middle Aged , Necrobiosis Lipoidica/complications , Treatment Outcome
4.
J Transplant ; 2011: 583981, 2011.
Article in English | MEDLINE | ID: mdl-21647349

ABSTRACT

Background. Our aim was to study the impact of clinical acute rejection (CR) and subclinical rejection (SR) on outcomes in kidney transplant recipients treated with rapid steroid withdrawal (RSW). Methods. All patients who received a living or deceased donor kidney transplant and were treated with RSW were included. The primary outcome was death-censored graft survival. Biopsies with Banff borderline changes were included with the rejection groups. Results. 457 kidney transplant recipients treated with RSW were included; 46 (10%) experienced SR, and 36 (7.8%) had CR. Mean HLA mismatch was significantly higher in the CR group. The Banff grade of rejection was higher in the CR group. There was a larger proportion of patients in both rejection groups with the combination of IFTA and persistent inflammation on the follow-up protocol biopsy done at 1 year. The estimated 5-year death-censored graft survival was 81% in SR, 78% in CR, and 97% in the control group (P < .0001). Significant differences were observed in allograft survival between the CR and control group (HR 9.06, 95% CI 3.39-24.2) and between the SR and control group (HR 4.22, 95% CI 1.30-13.7). Conclusion. Both SR and CR are associated with an inferior graft survival in recipients on RSW.

5.
Transplant Proc ; 42(7): 2650-2, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20832562

ABSTRACT

BACKGROUND: Earlier studies reporting outcomes after pancreas transplantation have included a combination of C-peptide cutoffs and clinical criteria to classify type 2 diabetes mellitus (T2DM). However, because the kidney is the major site for C-peptide catabolism, C-peptide is unreliable to discriminate the type of diabetes in patients with kidney disease. METHODS: To improve the discriminative power and better classify the type of diabetes, we used a composite definition to identify T2DM: presence of C-peptide, negative glutamic acid decarboxylase antibody, absence of diabetic ketoacidosis, and use of oral hypoglycemics. Additionally among T2DM patients with end-stage renal disease (ESRD), body mass index of <30 kg/m(2) and use of <1 u/kg of insulin per day were selection criteria for suitablity for simultaneous pancreas and kidney transplantation (SPKT). We compared graft and patient survival between T1DM and T2DM after SPKT. RESULTS: Our study cohort consisted of 80 patients, 10 of whom were assigned as T2DM based on our study criteria. Approximately 15% of patients with T1DM had detectable C-peptide. Cox regression survival analyses found no significant differences in allograft (pancreas and kidney) or patient survival between the 2 groups. The mean creatinine clearance at 1 year estimated by the modification of Diet in Renal Disease (MDRD) equation was not significantly different between the 2 groups. Among those with 1 year of follow-up, all patients with T2DM had glycosylate hemoglobin of <6.0 at 1 year versus 92% of those with T1DM. CONCLUSION: SPKT should be considered in the therapeutic armamentarium for renal replacement in selected patients with T2DM and ESRD. Use of C-peptide measurements for ESRD patients can be misleading as the sole criterion to determine the type of diabetes.


Subject(s)
C-Peptide/blood , Diabetes Mellitus, Type 1/surgery , Diabetes Mellitus, Type 2/surgery , Diabetic Nephropathies/surgery , Kidney Failure, Chronic/surgery , Kidney Transplantation/physiology , Pancreas Transplantation/physiology , Adult , Creatinine/blood , Diabetic Nephropathies/epidemiology , Diabetic Retinopathy/epidemiology , Female , Follow-Up Studies , Glycated Hemoglobin/analysis , Graft Rejection/epidemiology , Humans , Kidney Transplantation/immunology , Kidney Transplantation/mortality , Male , Middle Aged , Pancreas Transplantation/immunology , Pancreas Transplantation/mortality , Retrospective Studies , Survival Analysis , Tissue Donors/statistics & numerical data
6.
Am J Transplant ; 10(3): 563-70, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20121731

ABSTRACT

Our aim was to study the impact of subclinical inflammation on the development of interstitial fibrosis and tubular atrophy (IF/TA) on a 1-year protocol biopsy in patients on rapid steroid withdrawal (RSW). A total of 256 patients were classified based on protocol biopsy findings at months 1 or 4. Group 1 is 172 patients with no inflammation, group 2 is 50 patients with subclinical inflammation (SCI), group 3 is 19 patients with subclinical acute rejection (SAR) and group 4 is 15 patients with clinical acute rejection (CAR). On the 1-year biopsy, more patients in group 2 (SCI) (34%, p = 0.004) and group 3 (SAR) (53%, p = 0.0002), had an IF/TA score > 2 compared to group 1 (control) (15%). IF/TA was not increased in group 4 (CAR) (20%). The percent with IF/TA score > 2 and interstitial inflammation (Banff i score > 0) was higher in group 2 (16%, p = 0.004) and group 3 (37%, p < 0.0001) compared to group 1 (3%). In a multivariate analysis, patients in groups 2 or 3 had a higher risk of IF/TA score > 2 on the 1-year biopsy (OR 6.62, 95% CI 2.68-16.3). We conclude that SCI and SAR increase the risk of developing IF/TA in patient on RSW.


Subject(s)
Atrophy/etiology , Fibrosis/etiology , Inflammation , Kidney Transplantation/methods , Kidney Tubules/pathology , Adult , Aged , Biopsy , Female , Graft Rejection , Humans , Kidney Transplantation/adverse effects , Male , Middle Aged , Multivariate Analysis , Treatment Outcome
7.
Transplant Proc ; 41(10): 4172-7, 2009 Dec.
Article in English | MEDLINE | ID: mdl-20005362

ABSTRACT

INTRODUCTION: New-onset diabetes mellitus, which occurs after kidney transplant and type 2 diabetes mellitus (T2DM), shares common risk factors and antecedents in impaired insulin secretion and action. Several genetic polymorphisms have been shown to be associated with T2DM. We hypothesized that transplant recipients who carry risk alleles for T2DM are "tipped over" to develop diabetes mellitus in the posttransplant milieu. METHODS: We investigated the association of genetic and traditional risk factors present before transplantation and the development of new-onset diabetes mellitus after kidney transplantation (NODAT). Markers in 8 known T2DM-linked genes were genotyped using either the iPLEX assay or allelic discrimination (AD)-PCR in the study cohort testing for association with NODAT. We used univariate and multivariate logistic regression models for the association of pretransplant nongenetic and genetic variables with the development of NODAT. RESULTS: The study cohort included 91 kidney transplant recipients with at least 1 year posttransplant follow-up, including 22 who developed NODAT. We observed that increased age, family history of T2DM, pretransplant obesity, and triglyceridemia were associated with NODAT development. In addition, we observed positive trends, although statistically not significant, for association between T2DM-associated genes and NODAT. CONCLUSIONS: These findings demonstrated an increased NODAT risk among patient with a positive family history for T2DM, which, in conjunction with the observed positive predictive trends of known T2DM-associated genetic polymorphisms with NODAT, was suggestive of a genetic predisposition to NODAT.


Subject(s)
Diabetes Mellitus/epidemiology , Diabetes Mellitus/genetics , Kidney Transplantation/adverse effects , Polymorphism, Single Nucleotide , Postoperative Complications/epidemiology , Weight Gain/genetics , Age Factors , Body Mass Index , Cohort Studies , Family , Female , Genotype , Humans , Male , Medical History Taking , Pilot Projects , Regression Analysis , Risk Factors
8.
Am J Transplant ; 9(7): 1666-70, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19459799

ABSTRACT

With the current shortage of solid organs for transplant, the transplant community continues to look for ways to increase the number of organ donors, including extending the criteria for donation. In rhabdomyolysis, the byproducts of skeletal muscle breakdown leak into the circulation resulting in acute renal failure in up to 30% of patients. In nonbrain dead patients, this condition is reversible and most patients recover full renal function. Seven potential donors had rhabdomyolysis with acute renal failure as evidenced by the presence of urine hemoglobin, plasma creatinine kinase levels of greater than five times the normal and elevated creatinine. One donor required dialysis. At our institution, 10 kidneys were transplanted from the seven donors. Two grafts had immediate function, five grafts experienced slow graft function and three grafts had delayed graft function requiring hemodialysis. At a mean of 8.7 months posttransplant (2.4-25.2 months), all patients have good graft function, are off dialysis and have a mean creatinine of 1.3 (0.7-1.8). In conclusion, our experience suggests that rhabdomyolysis with acute renal failure should not be a contraindication for donation, although recipients may experience slow or delayed graft function.


Subject(s)
Acute Kidney Injury/etiology , Kidney Transplantation , Rhabdomyolysis/complications , Tissue Donors , Adolescent , Adult , Cadaver , Delayed Graft Function/etiology , Delayed Graft Function/physiopathology , Female , Humans , Kidney Transplantation/physiology , Male , Middle Aged , Retrospective Studies , Tissue Donors/supply & distribution , Young Adult
10.
Am J Transplant ; 7(8): 2039-41, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17578504

ABSTRACT

Laparoscopic donor nephrectomy can result in trauma to the kidney which may affect recipient graft function. In this case, the kidney sustained a complete degloving of the capsule during extraction. The kidney was transplanted and had immediate, good renal function, but postoperative course was complicated by a large urinoma that drained through the wound. Exploration was negative for a defined urine leak, but the surface of the denuded kidney was leaking a significant amount of unconcentrated urine. The patient was successfully treated with tissue glue treatment to the kidney surface and peritoneal window.


Subject(s)
Intraoperative Complications , Kidney Transplantation/adverse effects , Kidney/injuries , Laparoscopy/adverse effects , Nephrectomy/adverse effects , Tissue Donors , Tissue and Organ Procurement/methods , Female , Follow-Up Studies , Humans , Kidney/surgery , Kidney Transplantation/methods , Middle Aged , Nephrectomy/methods , Reoperation , Treatment Failure
11.
Transplant Proc ; 38(5): 1307-13, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16797289

ABSTRACT

Immunosuppression with rapid discontinuation of corticosteroids, usually with induction therapy, is safe in kidney transplant recipients. In 89 patients, we induced immunosuppression with basiliximab or rabbit antithymocyte globulin (17 and 72 patients, respectively). Selection criteria for basiliximab were age (>or=65 years), history (malignancy; chronic infection), and type 1 diabetes mellitus (eligible for pancreas transplant). Steroids were administered through posttransplantation day 4 (five doses); maintenance immunosuppression was with tacrolimus and mycophenolate mofetil. At last follow-up (average, 286 days), most patients were steroid-free (antithymocyte globulin, 90%; basiliximab, 88%). Protocol biopsies were performed at 1, 4, and 12 months posttransplantation. The overall risk of biopsy-proven acute rejection was 12%. At 6 months posttransplantation, acute rejection-free survival was 93% for antithymocyte globulin, 65% for basiliximab (P<.001). Median time to biopsy-proven acute rejection was 27 and 71 days, respectively. The low incidence of biopsy-proven acute rejection with steroid-avoidance immunosuppression may be further reduced with antithymocyte globulin.


Subject(s)
Antibodies, Monoclonal/adverse effects , Antilymphocyte Serum/adverse effects , Graft Rejection/epidemiology , Immunosuppressive Agents/adverse effects , Kidney Transplantation/immunology , Recombinant Fusion Proteins/adverse effects , Acute Disease , Adrenal Cortex Hormones , Adult , Aged , Animals , Basiliximab , Female , Humans , Male , Middle Aged , Patient Selection , Rabbits , Risk Factors
12.
Transplant Proc ; 37(4): 1785-8, 2005 May.
Article in English | MEDLINE | ID: mdl-15919466

ABSTRACT

Recent clinical trials have documented the short-term safety of steroid avoidance (SA) in kidney transplant recipients. Since July 2003, we have used a SA immunosuppression protocol for low-risk kidney transplant recipients. Eligibility criteria are age > or = 18, primary transplant (living or deceased donor), and tacrolimus started by postoperative day 3. Recipients were excluded if peak/current PRA was >50%/20%, or if they had a positive flow crossmatch, or if they had the recent use of corticosteroids (<6 months). All recipients received induction with rabbit anti-thymocyte globulin, total dose 6 mg/kg, or basiliximab. Recipients received 5 daily doses of corticosteroid and mycophenolate mofetil 1 gm twice daily starting on the day of transplantation. Tacrolimus was started when the serum creatinine level decreased by 20%, or by postoperative day 3. The goal for trough tacrolimus levels was 10-15 ng/mL for the first month, 8-12 ng/mL for months 2-3, and 5-10 ng/mL after month 3. Protocol biopsies (bx) were performed at reperfusion, 1 month, 4 months, and 12 months. Ninety-four kidney transplantations were performed during the study period. Sixty-seven recipients (71%) were eligible and enrolled in SA. Characteristics of the 67 SA recipients: mean age, 53 years (range, 26-70); 41% female; 67% Caucasian; 24% Hispanic; 15% African American; and 5% Native American. Also, 77% received a living donor kidney. The mean follow-up was 180 days (range, 10-360). At last follow-up, 91% remained steroid-free. Biopsy-proven acute rejection (BPAR) occurred in 5 recipients (7.5%). Three recipients (4.5%) had clinical BPAR and 2 had subclinical. One recipient died with pneumonia 4 months following transplantation. Posttransplantation diabetes mellitus (PTDM) occurred in 2 (5%) of 38 recipients. In the initial 41 recipients, 27 had protocol bx at 1 month and 13 at 4 months available for analysis. Chronic allograft nephropathy (CAN) was present on protocol bx in 48% at 1 month and 69% at 4 month. Actuarial (Kaplan-Meier method) patient and graft survival rates at 351 days were 97.8% and 96.8%, respectively. SA with anti-thymocyte globulin induction in low-immunologic risk kidney transplant recipients is safe and is associated with a low risk of BPAR. The incidence of PTDM appears to be lower.


Subject(s)
Adrenal Cortex Hormones/adverse effects , Immunosuppression Therapy/methods , Kidney Transplantation/immunology , Adult , Aged , Antilymphocyte Serum/therapeutic use , Female , Humans , Immunosuppressive Agents/therapeutic use , Male , Middle Aged , Postoperative Complications/chemically induced , Postoperative Complications/prevention & control , Tacrolimus/therapeutic use , Transplantation, Homologous/immunology
13.
Science ; 290(5490): 320-5, 2000 Oct 13.
Article in English | MEDLINE | ID: mdl-11030647

ABSTRACT

The preatmospheric mass of the Tagish Lake meteoroid was about 200,000 kilograms. Its calculated orbit indicates affinity to the Apollo asteroids with a semimajor axis in the middle of the asteroid belt, consistent with a linkage to low-albedo C, D, and P type asteroids. The mineralogy, oxygen isotope, and bulk chemical composition of recovered samples of the Tagish Lake meteorite are intermediate between CM and CI meteorites. These data suggest that the Tagish Lake meteorite may be one of the most primitive solar system materials yet studied.

14.
Atherosclerosis ; 111(1): 127-42, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7840808

ABSTRACT

Atherosclerotic lesion development was assessed in the thoracic aorta and chronically denuded iliac-femoral artery of hypercholesterolemic New Zealand White rabbits using inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase which have previously been shown to possess varying degrees of hepatoselectivity in rats. Atorvastatin, previously known as CI-981 (2.5 mg/kg), PD135022 (1.0 mg/kg), simvastatin (2.5 mg/kg), lovastatin (2.5 mg/kg), PD134965 (1.0 mg/kg), pravastatin (2.5 mg/kg) and BMY22089 (2.5 mg/kg) were added to a 0.5% cholesterol, 3% peanut, 3% coconut oil diet and fed for 8 weeks. Although reductions in plasma total cholesterol of 27% to 60%, VLDL-cholesterol of 31% to 71% and plasma total cholesterol exposure of 37% to 43% were obtained, no correlation between these parameters and vascular lipid content, lesion size or monocyte-macrophage content was noted. Iliac-femoral lipid content was unchanged; however, atorvastatin and simvastatin significantly reduced the cholesterol content of the thoracic aorta by 45%-62%. Atorvastatin and PD135022 reduced the size of the iliac-femoral lesion by 67% and monocyte-macrophage content by 72%. Simvastatin, lovastatin and PD134965 decreased the monocyte-macrophage content; however, lesion size was unchanged. Pravastatin and BMY22089 had no effect on lesion size or content. No compound significantly reduced the extent of thoracic aortic lesions. We concluded that changes in plasma lipids and lipoproteins noted with the various HMG-CoA reductase inhibitors did not account for the beneficial effect on atherosclerotic lesion development. The antiatherosclerotic potential of the HMG-CoA reductase inhibitors was compound-specific and clearly not a class effect.


Subject(s)
Anticholesteremic Agents/therapeutic use , Arteriosclerosis/drug therapy , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Animals , Arteriosclerosis/metabolism , Arteriosclerosis/pathology , Blood Vessels/metabolism , Blood Vessels/pathology , Cholesterol/blood , Cholesterol, Dietary/administration & dosage , Cholesterol, VLDL/blood , Lipid Metabolism , Liver/metabolism , Macrophages/pathology , Male , Monocytes/pathology , Rabbits
15.
Pharmacol Res ; 29(1): 65-76, 1994.
Article in English | MEDLINE | ID: mdl-8202444

ABSTRACT

Probucol, a cholesterol-lowering agent which possesses antioxidant properties, was evaluated in hypercholesterolemic Japanese quail in order to assess the significance of antioxidant therapy on the development of atherosclerosis. Forty quail were fed a 0.5% cholesterol diet containing 0, 100, 200 or 500 mg kg-1 probucol for 2 months. At necropsy, plasma total and lipoprotein cholesterol and lipoprotein distribution were unchanged despite plasma probucol levels of 50 to 59 micrograms ml-1. The cholesteryl ester content of the liver and blood vasculature (brachiocephalic artery and aortic arch combined) was reduced by 33% and 62%, respectively, in animals given 500 mg kg-1 probucol. The vascular free cholesterol content was also reduced by 43 to 60% over the probucol dose range. Morphometric analysis of the brachiocephalic artery revealed that probucol reduced the incidence of lesions containing esterase-positive cells from 62% in untreated animals to 26% and 13% in animals administered 200 and 500 mg kg-1 probucol, respectively. No difference in mean wall thickness or area of the bracheocephalic artery was noted between the groups. Thus, we conclude that probucol can blunt the cholesteryl ester and macrophage enrichment of atherosclerotic lesions and this activity appears to be mediated by the compound's antioxidant properties since the changes noted were seen in the absence of alterations in plasma total and lipoprotein cholesterol levels.


Subject(s)
Arteriosclerosis/drug therapy , Coturnix/metabolism , Hypercholesterolemia/complications , Probucol/therapeutic use , Animals , Aorta/pathology , Arteriosclerosis/etiology , Arteriosclerosis/pathology , Cholesterol/blood , Cholesterol Esters/blood , Cholesterol Esters/metabolism , Cholesterol, Dietary/administration & dosage , Diet, Atherogenic , Histocytochemistry , Hypercholesterolemia/blood , Hypercholesterolemia/metabolism , Lipoproteins/blood , Liver/metabolism , Male , Probucol/blood
16.
Atherosclerosis ; 102(1): 9-22, 1993 Aug.
Article in English | MEDLINE | ID: mdl-8257456

ABSTRACT

A biochemical, histologic and morphometric evaluation of spontaneous, diet-induced (thoracic aorta) and injury-induced (iliac-femoral) atherosclerotic lesions was performed in rabbits maintained on varying levels of dietary cholesterol. Rabbits were meal-fed a 3% peanut oil, 3% coconut oil diet containing 0%, 0.1%, 0.25%, 0.5%, 1.0%, 1.5% or 2.0% cholesterol for 9 weeks. Plasma total cholesterol exposure (area under cholesterol-time curve (TC-AUC)) increased diet-dependently over the course of the study. VLDL and LDL cholesterol (VLDL-C, LDL-C) comprised 41% and 55%, respectively, of the plasma total cholesterol at cholesterol levels > 700 mg/dl (TC-AUC > 31,868 mg day/dl) and both VLDL-C and LDL-C were linearly related to TC-AUC (r = 0.98). Plasma TC-AUC was linearly related to thoracic aortic cholesteryl ester (CE) content (r = 0.74) and thoracic aortic lesion coverage (r = 0.66). In the injury-induced iliac-femoral lesion, plasma TC-AUC was linearly related to both iliac-femoral CE content (r = 0.80) and macrophage/lesion ratio (r = 0.64). At plasma cholesterol levels greater than 700 mg/dl, CE content of the iliac-femoral lesion ranged from 35 to 69 micrograms/mg dry defatted tissue, > 75% of the lesions were fibrofoamy in nature and macrophage/lesion area ratio was 0.46 to 0.55 while lesion area remained constant. VLDL-C and LDL-C were highly correlated with the CE content of both thoracic and iliac-femoral lesions, thoracic aortic lesion coverage and macrophage/lesion area ratio (r = 0.86-0.99). We conclude that the composition, extent and type of atherosclerotic lesion induced in rabbits is dependent upon the overall plasma cholesterol exposure, VLDL and LDL cholesterol content and whether lesions are induced by diet alone or both diet and chronic endothelial injury. In addition, various stages of atherosclerotic lesion formation can be replicated in the rabbit by titrating the animal's overall plasma cholesterol exposure.


Subject(s)
Arteriosclerosis/pathology , Hypercholesterolemia/complications , Animals , Aorta, Thoracic/pathology , Arteriosclerosis/blood , Arteriosclerosis/complications , Cholesterol/metabolism , Cholesterol, Dietary/administration & dosage , Femoral Artery/pathology , Hypercholesterolemia/metabolism , Iliac Artery/pathology , Liver/metabolism , Male , Rabbits
17.
Atherosclerosis ; 99(2): 175-86, 1993 Mar.
Article in English | MEDLINE | ID: mdl-8503946

ABSTRACT

Atherosclerotic lesion development may be altered indirectly by regulating plasma cholesterol or directly by inhibition of acyl-CoA cholesterol O-acyltransferase (ACAT) within cells of the artery. Yucatan micropigs were meal-fed a 2% cholesterol, 8% peanut oil, 8% coconut oil purified diet for 1 month prior to administration of the potent, bioavailable ACAT inhibitor CI-976, and induction of atherosclerotic lesions by chronic endothelial damage. After 84-108 days of therapy, CI-976 decreased mean plasma VLDL-cholesterol 85-91% and cumulative VLDL-exposure (area under VLDL-time curve) by 65%. However, overall plasma total, LDL and HDL cholesterol and triglyceride levels were unchanged. CI-976 decreased liver cholesteryl ester (CE) content 65% without significantly affecting adrenal CE content. The CE content of the injured left femoral, left iliac and abdominal aorta and uninjured right femoral and iliac arteries and thoracic aorta was reduced 62-78% by CI-976. Systemic plasma CI-976 levels measured 24 h post-dose ranged from 2.26 to 4.05 micrograms/ml and significantly correlated with the reduction in both VLDL and vessel CE content. Thus, we conclude that inhibition of ACAT can blunt the cholesteryl ester enrichment of developing atherosclerotic lesions by preventing reesterification and storage of lipoprotein cholesterol within vascular cells and by reducing the plasma level and delivery to the arterial wall of such atherogenic lipoproteins as VLDL.


Subject(s)
Anilides/pharmacology , Arteriosclerosis/metabolism , Blood Vessels/metabolism , Cholesterol Esters/metabolism , Sterol O-Acyltransferase/antagonists & inhibitors , Adrenal Glands/metabolism , Animals , Arteriosclerosis/enzymology , Cholesterol/metabolism , Cholesterol, HDL/metabolism , Cholesterol, LDL/metabolism , Cholesterol, VLDL/metabolism , Liver/metabolism , Phospholipids/metabolism , Swine , Swine, Miniature
18.
Exp Mol Pathol ; 57(1): 70-83, 1992 Aug.
Article in English | MEDLINE | ID: mdl-1397193

ABSTRACT

Oxidative modification of LDL may represent an initiating event in the formation of monocyte-macrophage foam cells, a major cell present in fatty streaks and atherosclerotic fibrous plaques. Therefore, we studied the effect of such antioxidants as probucol (500 mg/kg) and vitamins E and C (500 mg/kg each) on the regression of induced iliac-femoral lesions and progression of naturally occurring thoracic aortic fatty streak lesions in hypercholesterolemic New Zealand White rabbits. Following an initial 9-week lesion induction phase, both therapies were evaluated for 8 weeks. Probucol lowered plasma cholesterol 47% while vitamins E and C had no effect on plasma cholesterol. Probucol decreased the cholesteryl ester (CE) content of the thoracic aorta by 31% without changing the thoracic aortic lesion coverage. Vitamins E and C decreased thoracic aortic CE content by 40% and lesion coverage by 46%. Neither probucol nor vitamins E and C altered the CE content, lesion size, or macrophage/lesion ratio of the iliac-femoral artery. Thus, we conclude that the effects of antioxidants are specific to the stage of atherosclerotic lesion development. Antioxidant therapy alters the progression and cholesteryl ester enrichment of diet-induced thoracic aortic fatty streaks but has no effect on the progression and/or regression of more complicated injury-induced iliac-femoral lesions.


Subject(s)
Antioxidants/therapeutic use , Arteriosclerosis/complications , Arteriosclerosis/drug therapy , Hypercholesterolemia/complications , Animals , Aorta/chemistry , Aorta/pathology , Arteriosclerosis/pathology , Ascorbic Acid/therapeutic use , Blood Vessels/chemistry , Blood Vessels/pathology , Cholesterol/analysis , Cholesterol/blood , Cholesterol Esters/analysis , Cholesterol Esters/blood , Femoral Artery/chemistry , Femoral Artery/pathology , Hypercholesterolemia/blood , Lipids/analysis , Lipids/blood , Lipoproteins/analysis , Lipoproteins/blood , Male , Probucol/therapeutic use , Rabbits , Vitamin E/therapeutic use
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