Chronic villitis of unknown etiology and massive chronic intervillositis have similar immune cell composition.

INTRODUCTION: Chronic villitis of unknown etiology (CVUE) and massive chronic intervillositis (MCI) are placental lesions associated with infiltration of mononuclear cells in the chorionic villi and the intervillous spaces, respectively. It is not well known whether immune cells in CVUE and MCI have similar phenotypic characteristics. METHODS: A cross-sectional study of third trimester placentas was conducted to identify immune cell subpopulations in CVUE and MCI (n = 17/group). CVUE was diagnosed with H&E staining and antibody to CD3 in serial sections; and MCI, by the presence of massive infiltration of mononuclear cells in the intervillous spaces. Immune cells, ICAM-1 expression and nuclear factor κB (NF-κB) activation were determined immunohistochemically. RESULTS: CVUE and MCI showed similar infiltrates, mainly CD68+ and CD3+ cells. Most cells (>80%) were CD45RB+, and one third were CD45RO+ in both lesions. There were slightly more CD8+ than CD4+ cells in both CVUE and MCI. More than 90% of cells in CVUE and MCI were ICAM-1+ with NFκB nuclear localization. Syncytiotrophoblast ICAM-1 expression was significantly (p < 0.001) higher in MCI (mean of 81.0; range of 71.6-86.0) than in CVUE (52.4; 36.4-59.4) or normal placentas (0.2; 0.0-0.6). Both, failure of physiologic transformation of spiral arteries and placental atherosclerosis-like lesions of atherosis were significantly more frequent in MCI than in CVUE or normal placentas (p = 0.044 and p = 0.007, respectively). DISCUSSION: These finding suggest that MCI and CVUE have very similar infiltration of immune cells although MCI has more severe placental lesions.

Intercellular adhesion molecule-1 expression in massive chronic intervillositis: implications for the invasion of maternal cells into fetal tissues.

INTRODUCTION: Massive chronic intervillositis (MCI), also known as chronic intervillositis of unknown etiology, is a placental lesion associated with massive infiltration of mononuclear cells in the intervillous space, poor perinatal outcome, and high rate of recurrence. Our previous demonstration of increased syncytiotrophoblast (st) intercellular adhesion molecule-1 (ICAM-1) expression in villitis lesions and the finding of extensive monocyte/macrophagic cells in the maternal intervillous space in MCI, led us to further investigate stICAM-1 in MCI. MATERIALS AND METHODS: A cross-sectional study of placentas from the third trimester of pregnancy (34-41 weeks gestation) was conducted to determine stICAM-1 in MCI (n = 7). MCI stICAM-1 expression was compared to stICAM-1 in villitis (n = 7) and in normal villi from placentas with (n = 7) and without (n = 7) villitis. Maternal cells within villi in MCI were identified in placentas mismatched for maternal/fetal human leukocyte antigen (HLA)-DRw52. Villitis was diagnosed with hematoxylin and eosin staining and antibody to CD3 in serial sections, and ICAM-1 in syncytiotrophoblasts was confirmed with antibodies to ICAM-1 and cytokeratin. RESULTS: Placentas with MCI had higher stICAM-1 (79.8%) than placentas with villitis (27.1%), normal villi from placentas with villitis (11.5%), and normal villi from placentas without villitis (0.3%). Maternal cells were identified within villi of placentas (n = 5) mismatched (mothers positive, fetuses negative) for HLA-DRw52. CONCLUSIONS: Placentas with MCI have more stICAM-1 than placentas with or without villitis lacking MCI. The finding that MCI and villitis have prominent stICAM-1 and maternal cells in the villi suggests that MCI and villitis could have a similar pathophysiologic mechanism.

Eritrograma de híbridos de surubim (Pseudoplatystoma reticulatum X P. coruscans) mantidos em diferentes densidades de estocagem / Erythrogram of hybrids surubins (Pseudoplatystoma coruscans X P. reticulatum) kept at different stocking densities

The blood profile of hybrid fish was studied. Pseudoplatystoma (P. coruscans X P. reticulatum) were submitted to different stocking densities in recirculating water system in two distinct phases of production. Hemoglobin concentration (Hg), packed cell volume (PCV) and mean corpuscular hemoglobin concentration (MCHC) were evaluated. There was no difference between the studied densities. Hemoglobin concentration, PCV and MCHC remained within the normal range for teleost fish.

Perfil bioquímico sanguíneo na intoxicação experimental com extrato de Mascagnia rigida (A. Juss.) Griseb. (Malpighiaceae) em coelhos / Biochemistry profile after experimental intoxication by extract of Mascagnia rigida (A. Juss.) Griseb. (Malpighiaceae) in rabbits

Avaliou-se o perfil bioquímico sanguíneo na intoxicação por Mascagnia rigida, uma planta tóxica que gera problema econômico para a pecuária, por causar morte súbita. Nove coelhos Nova Zelândia, machos, com massa corporal média de 3,54kg, foram distribuídos em três grupos (G) (n=3). Os animais receberam, durante oito dias consecutivos, o equivalente a 30g/kg de matéria seca da planta em dois tipos de extratos: solúvel em água (GS) e insolúvel em água (GI), e formou-se também o grupo-controle (GC). Os exames bioquímicos foram realizados previamente ao início do experimento até o nono dia. A administração dos extratos da Mascagnia rigida causou alterações eletrolíticas que podem justificar alguns sinais clínicos observados e atuar de forma significativa na causa mortis.

A study was carried out to evaluate the biochemical profile in Mascagnia rigida poisoning, a toxic plant that generates a significant economic problem to livestock, causing "sudden death". Nine New Zealand rabbits, male, 3,54kg mean body weight were divided into three groups (G) (n = 3). The animals received the equivalent of 30g/kg of dry matter in two types of extracts: water-soluble (GS) and insoluble in water (GI), and the control group (CG) (ultra-pure water) for eight consecutive days. Biochemical exams were done prior to the beginning of the experiment until the ninth day. It was concluded that the administration of extracts of Mascagnia rigida cause electrolyte imbalances that may justify some clinical signs and act significantly in the cause of death.

Early prediction of cardiac allograft vasculopathy and heart transplant failure.

Early risk-prediction is essential to prevent cardiac allograft vasculopathy (CAV) and graft failure in heart transplant patients. We developed multivariate models to identify patients likely to experience CAV, severe CAV, and failure due to CAV, at 1, 5 and 10 years. A cohort of 172 patients was followed prospectively for 6.7 ± 3.9 years. Logistic regression models were developed and cross-validated using bootstrap resampling. Predictive markers of atherothrombosis (myocardial fibrin deposition, and loss of vascular antithrombin and tissue plasminogen activator) and arterial endothelial activation (intercellular adhesion molecule-1 expression) were measured in serial biopsies obtained within 3 months posttransplant. Most markers were univariately associated with outcome. Multivariate models showed that loss of tissue plasminogen activator was the dominant and, in most cases, only predictor of long-term CAV (p < 0.001), severe CAV (p < 0.001), and graft failure due to CAV (p < 0.001). The models discriminated patients having adverse outcomes, had particularly high negative predictive values (graft failure due to CAV: 99%, 99% and 95% at 1, 5 and 10 years) and predicted event incidence and time to event. Early absence of atherothrombotic risk identifies a patient subgroup that rarely develops CAV or graft failure, implying that this low-risk subgroup could possibly be followed with fewer invasive procedures.

Hematological and biochemical profiles of rats submitted to experimental poisoning with Tityus serrulatus venom / Perfis hematológicos de ratos submetidos ao envenenamento escorpiônico experimental por Tityus serrulatus

The hematological and biochemical profiles of newly weaned rats submitted to experimental poisoning with T. serrulatus venom were evaluated. Fifteen recently weaned male Wistar rats (mean weight 130g) were distributed into three equal groups (n = 5). Animals in the control group (group A) received a subcutaneous injection of 400μL of ultra-pure water, while those in the experimental groups received, by identical route, 400μL of a solution containing 100μg (group B) or 450μg (group C) of scorpion venom dissolved in ultra-pure water. Red blood cells indexes, and differential leukocyte and total platelet counts were determined, together with levels of serum glucose, urea, creatinine, lactic dehydrogenase, aspartate aminotransferase, amylase, insulin, and cortisol. No significant differences between the control and experimental groups regarding red blood cells indexes were found. In contrast, significant increases (P<0.05) in neutrophils, lymphocytes, and monocytes were observed in animals from groups B and C compared with the control group, while the number of platelets decreased. Serum glucose concentration remained unchanged in all groups, but important alterations were observed in the values of urea and creatinine. The results show that scorpion venom was detrimental to renal function as demonstrated by the altered urea and creatinine levels. Pancreatic function was also impaired, as revealed by the increase in amylase activity and the reduction in insulin levels.

Avaliaram-se os perfis hematológico e bioquímico de ratos recém-desmamados submetidos ao envenenamento experimental com veneno de Tityus serrulatus. Quinze ratos Wistar machos, média de peso de 130g, foram distribuídos aleatoriamente em três grupos (n = 5). Os animais do grupo-controle A foram inoculados com 400μL de água ultrapura, os do grupo experimental B receberam 400μL de uma solução contendo 100μg de veneno e os do grupo experimental C receberam 400μL de uma solução contendo 450μg de veneno. Foram determinados os índices da série vermelha, a contagem total e diferencial dos leucócitos e a contagem total de plaquetas, bem como os níveis da desidrogenase lática, aspartato aminotransferase, amilase, glicose, ureia, creatinina, cortisol e insulina. Não houve diferenças significativas entre o grupo-controle e os experimentais com relação aos índices da série vermelha. Foram observados aumentos significativos (P<0,05) no número de neutrófilos, linfócitos e monócitos nos ratos dos grupos B e C, enquanto o número de plaquetas diminuiu. A concentração de glicose permaneceu inalterada em todos os grupos, mas foram observadas importantes alterações nos valores séricos de ureia e creatinina. Esses resultados mostraram que o veneno de escorpião comprometeu o funcionamento dos rins. Como demonstrado pelo aumento da atividade da amilase sérica e a redução dos níveis de insulina, a função pancreática também foi afetada.

Biochemical profile of dogs experimentally envenomed with Tityus serrulatus scorpion venom.

The aim of this study was to evaluate the canine blood and urinary profiles after envenomation by Tityus serrulatus venom. Twelve dogs were randomly distributed into two equal groups. Control group animals received 0.5 mL phosphate buffered saline (PBS) injected subcutaneously into the internal portion of the left thigh, whilst dogs in the envenomed group were injected with scorpion venom (250 microg/kg in 0.5 mL PBS). No significant alterations were detected in the urine of envenomed dogs. Levels of plasma glucose and serum urea, creatinine, total protein, potassium, alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), and amylase were determined. Semi-quantitative analysis of serum cardiac troponin I (cTnI) was performed using an immunochromatographic test. The concentrations of cortisol and insulin were determined using commercial radioimmunoassay kits. Increases in serum cortisol levels in experimental group animals coincided with hyperglycaemia and was probably a response to pain. Increased insulin levels were observed during the hyperglycaemic peaks. Envenomed dogs presented discreet increases in ALT, AST and CK, but no alterations in LDH, amylase, cTnI, urea, creatinine and potassium levels were observed. It was concluded that the venom of T. serrulatus induces blood and urinary biochemical changes in dogs.

Tityus fasciolatus envenomation induced cardio-respiratory alterations in rats.

The present study characterized envenomation in young rats by Tityus fasciolatus, an endemic scorpion to Central Brazilian and state of Minas Gerais. Electrocardiographic examinations were performed prior to treatment and every 5 min during the first 30 min after envenomation. The cardiac blood profile [creatine kinase, CK isoenzyme MB, lactate dehydrogenase, aspartate aminotransferase and troponina] together with macroscopic and microscopic alterations in the lungs and heart were evaluated. Envenomated animals showed ECG changes suggesting electrolytic imbalance, myocarditis and venom interference on the conduction tissue. Biochemical analyses indicated myocardial damage with high levels of CK, CK-MB and LDH. Macroscopic and microscopic findings included detection of pulmonary haemorrhages. In conclusion, T. fasciolatus venom leads to acute cardio-respiratory changes in young rats.

Hemograma de cães submetidos ao envenenamento experimental por Tityus serrulatus / Canine blood profile after experimental envenomation by Tityus serrulatus

Avaliou-se o hemograma de 12 cães adultos, saudáveis (14,2±5,4kg) após a inoculação de veneno do escorpião amarelo (Tityus serrulatus). Os animais foram distribuídos em dois grupos (G), com seis em cada: os do GI foram usados como controle e receberam 0,5mL de salina tamponada com fosfato (PBS) por via subcutânea (SC) na face medial da coxa esquerda (FMCE), e os do GII receberam veneno liofilizado do T. serrulatus (250µg/kg) diluído em PBS por via SC na FMCE. Foram realizadas colheitas de sangue com anticoagulante EDTA a 10 por cento antes da inoculação do veneno (T0) e após 2h, (T1), 6h (T2), 12h (T3), 24h (T4), 48h (T5) e 72h (T6), para contagem de eritrócitos, leucócitos e plaquetas em aparelho contador eletrônico e esfregaços sanguíneos para contagem diferencial de leucócitos. Houve aumento significativo (P<0,05) dos valores de eritrócitos, volume globular e hemoglobina 2h e 6h após o envenenamento, devido à contração esplênica decorrente da dor local causada pelo veneno e pela liberação de catecolaminas. Foi observada leucocitose por aumento significativo (P<0,05) de neutrófilos e linfócitos 2h e 6h após o envenenamento. Concluiu-se que o veneno de Tityus serrulatus na dose de 250µg/kg, é capaz de aumentar os valores do eritrograma e do leucograma dos cães, provavelmente devido à dor local, com liberação de catecolaminas.

The canine blood profile after scorpion envenomation was evaluated using 12 healthy mongrel male dogs (14.2±5.4kg) distributed in two groups, with six animals in each: group I (control group) and group II (venom group). The lyophilized yellow scorpion (Tityus serrulatus) venom (250µg/kg) diluted in 0.5mL phosphate buffered saline (PBS) was given to group II animals by subcutaneous injection, in the medial face of the left thigh. Group I animals received only 0.5mL of PBS, by subcutaneous injection, in the medial face of the left thigh. Blood samples were collected with EDTA before (T0) and 2 (T1), 6 (T2), 12 (T3), 24 (T4), 48 (T5), and 72h (T6) after envenomation. Significant increases (P<0.05) in erythrocytes counting, hematocrit and hemoglobin concentration, 2 and 6h after envenomation were observed. Leukocytosis with significant increases (P<0.05) of neutrophils and lymphocytes 2 and 6h after envenomation was found. Then, T. serrulatus venom may induce alterations in blood profile in dogs, probably due to spleen contraction evoked by pain and catecholamines releasing.

LacSwitch II regulation of connexin43 cDNA expression enables gap-junction single-channel analysis.

Metabolic and electrical coupling through gap junction channels is implicated in cell differentiation, tissue homeostasis, and electrotonic propagation of signals in excitable tissues. The characterization of gating properties of these channels requires electrophysiological recordings at both single- and multiple-channel levels. Hence, a system that is able to control connexin expression by external means would provide a useful tool. To regulate the expression of connexins in cells, plasmids encoding a transactivator and/or a lac-operon IPTG response-dependent Cx43 target gene were transfected into communication-deficient N2a neuroblastoma cells. Immunoblotting, dye coupling, and electrophysiological methods revealed that expression of Cx43 in selected clones could be tightly regulated. After 15-20 h of acute induction with IPTG, cell-to-cell communication reached its peak with junctional conductances of 15-30 nS. Chronic induction at specific doses of IPTG produced constant, controlled levels of Cx43 expression, which were reflected by predictable junctional coupling levels. These conditions allowed prolonged recordings from either lowly or highly coupled cells, making lac operon an ideal regulatory system for channel gating studies at a single-channel level.

Primary cutaneous microangiopathy in heart recipients.

In this study we investigated whether a disturbance in microcirculation is detectable in heart recipients with cardiac allograft vasculopathy (CAV) and severe hypercholesterolemia (n = 11) and in 7 heart recipients without CAV in comparison to patients with severe coronary artery disease (n = 49) and age-matched apparently healthy subjects (n = 100). For this purpose, the flow velocity of erythrocytes through cutaneous capillaries at the nail fold of the finger was measured under resting conditions. In addition, reactive hyperemia in the same capillaries after a 3-min ischemia was determined. Patients with CAV and severe lipid disorder showed a pathological reduction in mean capillary erythrocyte velocity under resting conditions with v(RBC) = 0.10 +/- 0.07 mm/s. The latter was significantly and relevantly lower than in patients with coronary three-vessel disease (v(RBC) = 0.46 +/- 0.35 mm/s). It was notable that under resting conditions temporary cessation of flow occurred in 8 of the 11 patients which did not occur in healthy subjects and rarely in patients with three-vessel disease (1 of 49 patients). In comparison to age-matched healthy subjects (v(max) = 1.46 +/- 0.52 mm/s), the patients with three-vessel disease showed a significant reduction in postischemic maximum erythrocyte velocity (v(max) = 0.85 +/- 0.55 mm/s), with a considerable shortening of the duration of reactive hyperemia. Patients with CAV demonstrated a total loss of postischemic reactive hyperemia (only 1 of the 11 patients presented a weak reactive hyperemia). Since no macroangiopathy was detectable in the upstream arm arteries, primary cutaneous microangiopathy can be assumed in patients with cardiac allograft vasculopathy and severe hypercholesterolemia.

Vascular antithrombin and clinical outcome in heart transplant patients.

A procoagulant microvasculature is associated with accelerated development of coronary artery disease (CAD) and failure in heart transplant patients. This study was performed to evaluate how changes in natural anticoagulation within cardiac allografts affect outcome. We prospectively studied 141 consecutive cardiac allograft recipients who underwent transplantation between 1988 and 1997. Serial endomyocardial biopsy specimens (6.5 +/- 0.1 biopsy specimens/patient) obtained during the first 3 months after transplantation were studied immunohistochemically to evaluate vascular antithrombin, and annual coronary angiograms (3.8 +/- 0.2 angiograms/patient) were studied to evaluate CAD. Antithrombin was present in arteries and veins, but not in capillaries, of all donor heart biopsy samples. Allografts that maintained vascular antithrombin had the best prognosis. Allografts with early and persistent loss of vascular antithrombin (n = 21) developed CAD earlier (p < 0.001), developed more severe disease (p < 0.001), showed more disease progression (p < 0.001), and failed more often (p = 0.003) and earlier (p < 0.001) than allografts retaining normal vascular antithrombin (n = 45). However, allografts that lost and recovered vascular antithrombin while developing unusual capillary antithrombin binding (n = 75) had less CAD, developed CAD later, had less severe disease and less disease progression (p < 0.01), and failed less often (p = 0.01) and later (p = 0.03) than allografts with persistent loss of vascular antithrombin. The persistent lack of a thromboresistant microvasculature increases risk of subsequent CAD and graft failure. However, recovery of vascular antithrombin and development of unusual capillary antithrombin binding improves allograft outcome.

Pathologic markers of allograft arteriopathy: insight into the pathophysiology of cardiac allograft chronic rejection.

Transplant-associated coronary artery disease (CAD) is the principal limiting factor for the long-term survival of heart transplant patients. This review discusses early risk factors for the subsequent development of transplant-associated CAD. Early risk factors associated with a prothrombogenic microvasculature, such as deposition of microvascular fibrin, depletion of vascular tissue plasminogen activator, presence of endothelial activation of the allograft arterial tree, and loss of vascular antithrombin, as well as changes in circulation (ie, detectable serum cardiac troponin I and elevated serum soluble intercellular adhesion molecule-1 levels) are presented and discussed. New therapies that could improve the status of the allograft microvasculature and may prevent or mitigate the development of transplant-associated CAD are considered.

Increased vascular endothelial growth factor expression in human hearts with microvascular fibrin.

We have shown that microvascular changes that promote fibrin deposition in human cardiac allografts adversely affect clinical outcome. However, some allografts exhibit phenotypic changes in capillaries following the deposition of fibrin, which subsequently provide a significant survival advantage. The mechanism(s) involved in these capillary changes is(are) unknown. Similarly, although we have shown a significant temporal relationship between microvascular fibrin deposition and vascular endothelial growth factor (VEGF) immunoreactivity in cardiac allografts, the cellular source and relative changes in VEGF gene expression under these conditions are not known. Using immunocytochemical techniques, biopsies devoid of fibrin deposition lacked detectable VEGF immunoreactivity, whereas biopsies with fibrin deposition showed VEGF immunoreactivity in cardiocytes, interstitium, and some microvessels. By in situ hybridization, biopsies without microvascular fibrin deposition showed faint VEGF hybridization signals confined primarily to cardiocytes. In biopsies with fibrin deposition, strong VEGF hybridization signals were detected in cardiocytes, arteriolar smooth muscle cells were occasionally labeled, and endothelial cells were rarely labeled. By quantitative RT-PCR, biopsies with fibrin deposition (n=5) relatively expressed approximately three-fold more VEGF mRNA than biopsies without fibrin deposition (n=5 P=0.02). Serum VEGF titers also were greater (P=0.01) in recipients with fibrin deposition (372.9+/-66.7 pg/ml n=18) compared to recipients without fibrin deposition (172.1+/-25.0 pg/ml n=16). Collectively, these results support the hypothesis that increased myocyte-derived VEGF production following microvascular fibrin deposition in transplanted human hearts may act in a paracrine manner to promote activational and phenotypic changes in capillaries that provide a survival advantage for the allografts.

Platelet cryopreservation using a combination of epinephrine and dimethyl sulfoxide as cryoprotectants.

Current methods of platelet storage are unsatisfactory because of the short shelf life of platelets and the rapid loss of platelet viability. We have developed a cryopreservation method that results in less damage from freezing and higher recovered function of platelets. Platelets were cryopreserved using a combination of epinephrine (EPN) and dimethyl sulfoxide (Me(2)SO) as cryoprotectants. The response of platelets to agonists was studied by flow cytometry and aggregation tests. Cryopreserving platelets with Me(2)SO decreased platelet annexin V binding due to freezing. The combination of EPN with Me(2)SO enhanced Me(2)SO cryoprotection and decreased platelet microparticle generation, suggesting that cryopreserving platelets using this combination is associated with increased platelet integrity. Platelet cryopreservation with an Me(2)SO/EPN combination also increased platelet aggregability, which was demonstrated by decreasing the lag phase and increasing the aggregation density to 66.39% +/- 6.6 that of fresh platelet-rich plasmas. We conclude that adding EPN as a combined cryoprotectant improves the quality of Me(2)SO-frozen platelets. As a method of aggregation of cryopreserved platelets, this method is comparable to that of normal fresh platelets and may improve the conditions for platelet transfusion.

Value of serum-soluble intercellular adhesion molecule-1 for the noninvasive risk assessment of transplant coronary artery disease, posttransplant ischemic events, and cardiac graft failure.

BACKGROUND: Adhesion molecules on arterial endothelium have been implicated in spontaneous atherosclerosis and transplant coronary artery disease (CAD). We studied whether elevated serum-soluble intercellular adhesion molecule-1 (sICAM-1) during the immediate posttransplant period was a risk factor for CAD, posttransplant ischemic events, or cardiac graft failure. METHODS AND RESULTS: We initially studied serum sICAM-1 in a subset of 16 cardiac allograft recipients (5.5+/-0.7 samples per patient) to determine a cutoff point that best correlated with presence of arterial and arteriolar endothelial ICAM-1 in matching endomyocardial biopsies. The cutoff value was 308 ng/mL. Subsequently, we prospectively evaluated serum sICAM-1 in serial samples (5.3+/-0.1 per patient) obtained during the first 3 months after transplantation in a validation subset of 130 recipients and correlated early sICAM-1 levels with long-term outcome. Serum sICAM-1 >308 ng/mL correlated significantly with ICAM-1 on arterial and arteriolar endothelium (P:=0.02). Cardiac allograft recipients with serum sICAM-1 >308 ng/mL had 2.67 (95% CI, 1.28 to 5.59, P:=0.009) times greater risk of CAD and 3.63 (95% CI, 1.05 to 12.5, P:=0.04) times greater risk of graft failure. Recipients with sICAM-1 >308 ng/mL also developed more severe CAD (P:=0.009) and more ischemic events (P:=0.03) after transplantation. CONCLUSIONS: Serum sICAM-1 levels can be used to noninvasively assess risk of transplant CAD, posttransplant ischemic events, and cardiac graft failure.

Cardiac-specific troponin I levels and risk of coronary artery disease and graft failure following heart transplantation.

CONTEXT: Previous studies have yielded conflicting data regarding whether a relationship exists between elevated cardiac troponin levels and acute allograft rejection in patients who have received heart transplants. OBJECTIVE: To determine whether cardiac troponin I levels after heart transplantation were associated with a procoagulant microvasculature and long-term allograft outcome. DESIGN: Prospective cohort study with a mean (SE) follow-up of 45.1 (2.5) months. Serum troponin I levels were measured 9.9 (0.2) times per patient during the first 12 months after heart transplantation. SETTING: Heart transplant center in the United States. PATIENTS: A total of 110 consecutive patients who received a heart transplant between 1989 and 1997 and survived at least 1 year after transplantation. MAIN OUTCOME MEASURES: Histological and immunohistochemical biopsy findings, development of coronary artery disease (CAD), and graft failure in patients with vs without elevated serum cardiac troponin I levels. RESULTS: All recipients had elevated troponin I levels during the first month after transplantation. Troponin I levels remained persistently elevated during the first 12 months in 56 patients (51%) and became undetectable in 54 patients (49%). Persistently elevated troponin I levels were associated with increasing fibrin deposits in microvasculature and cardiomyocytes (P<.001). Patients with persistently elevated levels of troponin I had significantly increased risk for subsequent development of CAD (odds ratio [OR], 4. 3; 95% confidence interval [CI], 1.8-10.1; P<.001) and graft failure (OR, 3.4; 95% CI, 1.2-9.7; P =.02), and also developed more severe CAD (OR, 4.2; 95% CI, 1.9-9.3; P<.001) and showed more disease progression (OR, 3.7; 95% CI, 1.3-10.4; P =.009). CONCLUSION: In this study, elevated cardiac troponin I levels, which are considered to be a noninvasive surrogate marker of a procoagulant microvasculature, identified a subgroup of patients with high risk for developing CAD and graft failure after cardiac transplantation. JAMA. 2000;284:457-464