Studies investigating pretransplant donor-specific blood transfusion,rapamycin, and the CD154-specific antibody IDEC-131 in a nonhuman primate model of skin allotransplantation

Anti-CD154 variably prolongs allograft survival in nonhuman primates. Rodent studies suggest that adding pretransplant donor-specific transfusion (DST) and/or rapamycin to anti-CD154 improves survival. The CD154-specific Ab IDEC-131 was tested alone and in combination with rapamycin for its ability to inhibit rhesus MLRs. The ability of the Ab to block endothelial activation was also assessed. IDEC-131 was then tested alone and in combination with DST and/or rapamycin for its ability to prevent rejection of full-thickness, MHC-mismatched rhesus skin allografts. Animals were monitored for donor-specific hyporesponsiveness by MLR and alloantibody determination. IDEC-131 modestly inhibited rhesus MLRs and inhibited CD154-dependent endothelial cell activation. Rapamycin combined with IDEC-131 additively inhibited MLRs. IDEC-131 modestly prolonged allograft survival when compared with no treatment, rapamycin alone, or DST plus rapamycin. Adding DST to IDEC-131 did not prolong survival beyond IDEC-131 alone. IDEC-131 plus rapamycin was effective in prolonging graft survival, although animals had episodes of acute rejection before graft demise. Therapy with IDEC-131, rapamycin, and DST induced long-term allograft survival without intermittent acute rejection. However, no evidence for MLR inhibition was seen, and most animals eventually developed alloantibody. All animals ultimately rejected their grafts after drug withdrawal. IDEC-131 modestly prolongs rhesus skin allograft survival. Rapamycin and rapamycin plus DST improves the efficacy of IDEC-131 in prolonging allograft survival. IDEC-131, rapamycin, and DST are a promising combination for clinical evaluation in allotransplantation.     

A study of human cardiac allograft in a patient with four-year survival

A report is presented of a patient surviving four years with a human cardiac allograft. The allograft arteries showed marked graft arteriosclerosis with intimal fibrocellular proliferation. The arteriosclerotic lesions occurring in the larger epicardial vessels were strikingly similar to spontaneous atherosclerosis. The relationship of the long-term survival to the use of a permanent transvenous pacemaker and of the development of severe vascular lesions to acute rejection and hyperlipemia are discussed.     

Cardiac transplantation and resistance artery myogenic tone

Transplantation is an effective treatment for end-stage heart disease; however, most grafts eventually fail by progressive cardiac failure. Primarily, failure is ischemic due to the occlusive nature of transplant vascular disease (TVD). Early after transplantation and preceding TVD, alterations in coronary physiology such as reduced vascular myogenic tone occur. Resistance arteries possess an inherent ability to constrict in response to transmural pressure; this constrictive response (myogenic tone) is important in fluid homeostasis. Recent evidence suggests that a decline in myogenic tone leads to deficits in cardiac contractility. Factors that reduce myogenic tone in transplantation include constitutive nitric oxide synthase and inducible nitric oxide synthase catalyzed, NO-mediated vasodilation as well as deficits in arterial contractile function. Reduced myogenic tone in allograft resistance arteries increases coronary blood flow such that hydrostatic pressure surpasses oncotic pressure, causing cardiac interstitial edema. This generalized edema decreases ventricular compliance leading to heart failure during the course of acute immune rejection of the graft. Cyclosporine A treatment reduces immune mediated dysregulation of myogenic tone, resulting in reduced interstitial edema and improved cardiac function. In this review, we discuss aspects of TVD and myogenic tone signaling mechanisms and how aberrations in myogenic regulation of arterial tone contribute to functional changes observed in cardiac transplant.     

CCR5 blockade in combination with cyclosporine increased cardiac graft survival and generated alternatively activated macrophages in primates

Maraviroc (MVC), a specific antagonist of CCR5 expressed on macrophages and activated T cells, may modulate inflammation and may be useful in patients with HIV infection. In this study we used nonhuman primates to examine the effect and mechanism of MVC alone or in combination with cyclosporine (CsA) to prolong cardiac allograft survivals. In an established rhesus monkey cardiac allograft model, recipients treated with MVC plus CsA showed significantly prolonged survival of heart allografts (>240 d, p < 0.001). These in vivo results in the MVC/CsA group correlated with delayed alloantibody response and markedly decreased graft infiltration by CCR5(+), CD4(+), CD8(+), and CD68(+) cells (p < 0.05), as compared with other groups. Furthermore, grafts from the MVC/CsA group had elevated numbers of alternatively activated macrophages (AAMs) and the expression of peroxisome proliferator-activated receptor γ (PPARγ). Blockade of PPARγ abrogated the prolonged allograft survival (median survival time, 45 d) and the upregulated AAMs in MVC/CsA-treated recipients. In conclusion, MVC/CsA protects cardiac allograft in primates and this effect is associated with generating AAMs through activation of the PPARγ nuclear receptor.     

CCR5 blockade modulates inflammation and alloimmunity in primates

Pharmacologic antagonism of CCR5, a chemokine receptor expressed on macrophages and activated T cells, is an effective antiviral therapy in patients with macrophage-tropic HIV infection, but its efficacy in modulating inflammation and immunity is only just beginning to be investigated. In this regard, the recruitment of CCR5-bearing cells into clinical allografts is a hallmark of acute rejection and may anticipate chronic rejection, whereas conventionally immunosuppressed renal transplant patients homozygous for a nonfunctional Delta32 CCR5 receptor rarely exhibit late graft loss. Therefore, we explored the effects of a potent, highly selective CCR5 antagonist, Merck's compound 167 (CMPD 167), in an established cynomolgus monkey cardiac allograft model. Although perioperative stress responses (fever, diminished activity) and the recruitment of CCR5-bearing leukocytes into the graft were markedly attenuated, anti-CCR5 monotherapy only marginally prolonged allograft survival. In contrast, relative to cyclosporine A monotherapy, CMPD 167 with cyclosporine A delayed alloantibody production, suppressed cardiac allograft vasculopathy, and tended to further prolong graft survival. CCR5 therefore represents an attractive therapeutic target for attenuating postsurgical stress responses and favorably modulating pathogenic alloimmunity in primates, including man.     

Age-Related Changes of Elements in the Coronary Arteries of Monkeys in Comparison with Those of Humans

To elucidate compositional changes of the coronary artery with aging, the authors investigated age-related changes of elements in the coronary arteries of rhesus and Japanese monkeys by direct chemical analysis in comparison with the coronary arteries of Japanese and Thai. Used monkeys consisted of 38 rhesus monkeys and 23 Japanese monkeys, ranging in age from newborn to 33 years. After perfusion with a fixative, the hearts were resected from the monkeys, and the anterior interventricular branches of the left coronary artery and the right coronary arteries were resected from the hearts. After ashing of the arteries, element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the Ca and P contents did not increase in both the left and right coronary arteries of rhesus and Japanese monkeys at old age. The average contents of Ca and P decreased by 13% and 25% in the left coronary arteries more than 20 years of age in comparison with those below 20 years of age, whereas they decreased by 4% and 15% in the right coronary arteries more than 20 years of age in comparison with those below 20 years of age. This finding indicated that atherosclerosis scarcely occurred in both the left and right coronary arteries of rhesus and Japanese monkeys at old age. In contrast with monkeys, atherosclerosis occurred frequently in the coronary arteries of Japanese and Thai at old age.     

Cardiac allotransplantation across major blood group barriers in the baboon

In heterotopic heart transplantation experiments in Chacma baboons, some of the animals were significantly immunosuppressed with cyclosporine, resulting in prolonged cardiac allograft survival. ABO blood group incompatibility between recipient and donor did not significantly influence mean allograft survival, but early hyperacute (vascular) or acute (cellular) rejection occurred only when ABO incompatibility was present.     

Balanced expression of mitochondrial apoptosis regulatory proteins correlates with long-term survival of cardiac allografts

Abnormal regulation of apoptosis is observed in ischemic injury and may contribute to the pathogenesis of atherosclerosis. However, its role in cardiac allograft vasculopathy (CAV), the fundamental lesion of chronic rejection (CR) in heart transplantation, remains uncertain. To clarify this issue, apoptosis was quantitated in myocardium and coronary arteries from 5 cardiac allograft donors (NL) and explanted hearts of 24 patients with ischemic cardiomyopathy (IsCM) and 15 patients with CR. Tissue samples were analyzed via end-labeling fragmented DNA [via deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)] and immunoblotting for activated caspase-3 and -9. Myocyte apoptosis assessed by TUNEL was similarly increased over NL (0.21%) in both the CR (0.88%; P < 0.01) and IsCM (0.88%; P < 0.01) groups. Activated caspase-9 levels were significantly higher in CR (14.7%) compared with IsCM (6.9%; P < 0.01) and NL (0%) groups, whereas activated caspase-3 levels were similarly elevated in both CR and IsCM (7.8 and 6.5% vs. 0% in NL; P < 0.01 and P < 0.05) groups. Expression of myocardial Bcl-2 and Bax was increased in CR compared with both NL (Bax, 4.3-fold; P < 0.01; Bcl-2, 5.9-fold; P < 0.01) and IsCM (IsCM: Bax, 2.2-fold; P < 0.05; Bcl-2, 3.2-fold; P < 0.01) groups. The rate of apoptosis and the Bcl-2/Bax ratio independently correlated to graft survival in CR (activation of caspase-9: r = 0.87; P < 0.01; Bcl-2/Bax: r = 0.57; P = 0.05). Compared with native atherosclerosis, coronary arteries with CAV showed more medial apoptosis (7.8-fold; P < 0.01) and higher Bcl-2 levels (5.1-fold; P < 0.01) with lower Bax levels (threefold; P < 0.05) in the intima. These results indicate that abnormal Bcl-2 and Bax expression in myocardium and coronary arteries of cardiac allografts with CR is distinct from that in IsCM and suggest that balancing Bcl-2 to Bax in transplanted hearts promotes long-term graft survival.     

Pathology of modified graft-versus-host disease in bone marrow allografted monkeys treated with antilymphocyte serum.

Lethally irradiated rhesus monkeys were used for bone marrow allografting and autografting. Monkeys receiving allogeneic bone marrow developed acute graft-versus-host reaction (GVHR) and had a mean survival time of 9.1 days as compared to autografted monkeys which survived above 500 days. Treatment with antilymphocyte sera (ALS) before allografting modified the GVHR and extended the survival time to an average of 43 days. Histologically, such animals showed evidence of "chronic" GVHR and septicemia secondary to a lack in lymphoreticular recovery. Subsequently, severe GI-tract infections followed which usually served as portal of entry for septicemia.     

B lymphocytes differentially influence acute and chronic allograft rejection in mice

The relative contributions of B lymphocytes and plasma cells during allograft rejection remain unclear. Therefore, the effects of B cell depletion on acute cardiac rejection, chronic renal rejection, and skin graft rejection were compared using CD20 or CD19 mAbs. Both CD20 and CD19 mAbs effectively depleted mature B cells, and CD19 mAb treatment depleted plasmablasts and some plasma cells. B cell depletion did not affect acute cardiac allograft rejection, although CD19 mAb treatment prevented allograft-specific IgG production. Strikingly, CD19 mAb treatment significantly reduced renal allograft rejection and abrogated allograft-specific IgG development, whereas CD20 mAb treatment did not. By contrast, B cell depletion exacerbated skin allograft rejection and augmented the proliferation of adoptively transferred alloantigen-specific CD4(+) T cells, demonstrating that B cells can also negatively regulate allograft rejection. Thereby, B cells can either positively or negatively regulate allograft rejection depending on the nature of the allograft and the intensity of the rejection response. Moreover, CD19 mAb may represent a new approach for depleting both B cells and plasma cells to concomitantly impair T cell activation, inhibit the generation of new allograft-specific Abs, or reduce preexisting allograft-specific Ab levels in transplant patients.     

Apport de l’IRM cardiaque à l’exploration des cardiopathies ischémiques

This article presents the current and future possibilities of the cardiac magnetic resonance imaging (MRI) in the ischemic heart disease. It is not an emergency technique, but is becoming an element of decision for an acute myocardial infarction. It makes it possible to visualize the extent of the myocardial lesions in post acute infarction, to appreciate functional recovery and to uncover a nonsymptomatic coronary stenosis or of atypical clinical presentation. The visualization of the coronary arteries in MRI is realizable, but remains experimentation field. The cardiac MRI place is to be defined by each medical team according to their diagram of ischemic heart disease follow-up.     

Experimental candida-induced arteritis in mice. Relation to arteritis in the mucocutaneous lymph node syndrome.

An extract of Candida albicans isolated from a patient with typical mucocutaneous lymph node syndrome (MCLS) can produce coronary arteritis in a mouse when injected intraperitoneally. An unusual feature of this arteritis is that it is granulomatous, shows no fibrinoid change and is confined to the coronary arteries. These characteristics are quite similar to those found in patients with MCLS.     

Senile Cardiac Amyloidosis in The Dog

Thirty-two cases of senile cardiac amyloidosis from a routine necropsy material of 594 dogs were studied. The age of the affected dogs ranged from 10 to 16 years. Amyloid was observed in the intramural arteries and arterioles, predominantly in the ventricular myocardium. The vessels were often obturated with amyloid, and myocardial necroses and fibroses were common consequences of the vascular lesions. In three cases amyloid deposits were also observed in the main subepicardial coronary arteries. In contrast to man, only slight interstitial amyloid degeneration was found in four of the dogs observed. Amyloid in the mitral valves, tricuspid valves and aortic cusps was observed in six, two and three cases respectively. It was concluded that the distribution of senile cardiac amyloidosis in the heart of the dog differs considerably from that in man.     

Extensive right coronary artery thrombosis

A 65-year-old man presented with a non-ST-elevation acute coronary syndrome. His medical history was unremarkable. Apart from a brother, who sustained a myocardial infarction at the age of 40, no cardiovascular risk factors were present. Coronary angiography revealed normal left anterior descending and circumflex arteries. The right coronary artery was subtotally occluded with an extensive thrombus running into the posterolateral branch (figures 1A and B). Despite appropriate medical treatment, intermittent chest pain persisted. The patient underwent a percutaneous coronary intervention with mechanical removal of the thrombus by aspiration followed by balloon dilatation.     

Importance of endothelial VCAM-1 for inflammatory leukocytic infiltration in vivo.

The microvascular endothelia of rejecting DBA/2----C57B1/6 murine cardiac allografts develop reactivity with the mAb M/K-2, which recognizes the murine homologue of the human leukocyte adhesion molecule VCAM-1. This reactivity does not develop in DBA/2----DBA/2 cardiac isografts or normal DBA/2 cardiac tissues. To determine whether endothelial VCAM-1 plays a role in allograft inflammation, cardiac allograft recipients were treated with M/K-2 antibody and monitored for leukocytic graft infiltration and graft survival. Treatment of the graft recipients with 200 micrograms/day M/K-2 Ig prolonged graft survival by 5 to 6 days (statistically significant); whereas treatment with 100 micrograms M/K-2 Ig every other day after transplant did not influence graft survival. Neither treatment interfered with leukocytic infiltration, as detected histologically or by limiting dilution analysis. The high dose treatment, but not the low dose treatment, resulted in high circulating levels of M/K-2, as detected by serum ELISA, and prominent antibody deposition on the graft vascular endothelia, as demonstrated by immunohistologic analysis. These data demonstrate that VCAM-1 is uniquely expressed on the vascular endothelia of rejecting murine cardiac allografts, and that a mAb to VCAM-1 can interfere with the allograft rejection process. Although this antibody can interfere with lymphocyte-endothelial adhesion in vitro, it has little effect on leukocytic infiltration in rejecting allografts suggesting that this process does not depend exclusively on VCAM-1 expression.     

Combined CXCR3/CCR5 blockade attenuates acute and chronic rejection

Chemokine-chemokine receptor interactions orchestrate mononuclear cells recruitment to the allograft, leading to acute and chronic rejection. Despite biologic redundancy, several experimental studies have demonstrated the importance of CXCR3 and CCR5 in acute rejection of allografts. In these studies, deficiency or blockade of CXCR3 or CCR5 led to prolongation of allograft survival, yet allografts were ultimately lost to acute rejection. Given the above findings and the specificity of mononuclear cells bearing CXCR3 and CCR5, we hypothesized that combined blockade of CXCR3 and CCR5 will lead to indefinite (>100 days) graft survival in a full MHC-mismatched murine cardiac allograft model. The donor hearts in the control group were rejected in 6 +/- 1 days after transplantation. Combined blockade of CXCR3 and CCR5 prolonged allograft survival >15-fold vs the control group; all allografts survived for >100 days. More importantly, the donor hearts did not display any intimal lesions characteristic of chronic rejection. Further analysis of the donor hearts in the CXCR3/CCR5 blockade group demonstrated graft infiltration with CD4(+)CD25(+) T cells expressing the Foxp3 gene. Depletion of CD25(+) cells in the combined CXCR3 and CCR5 blockade group resulted in acute rejection of the allografts in 22 +/- 2 days. Combined CXCR3 and CCR5 blockade also reduced alloantigen-specific T lymphocyte proliferation. Combined CXCR3 and CCR5 blockade is effective in preventing acute and chronic rejection in a robust murine model. This effect is mediated, in part, by CD25(+) regulatory T cell recruitment and control of T lymphocyte proliferation.     

TNF-alpha is necessary for induction of coronary artery inflammation and aneurysm formation in an animal model of Kawasaki disease

Kawasaki disease is the most common cause of multisystem vasculitis in childhood. The resultant coronary artery lesions make Kawasaki disease the leading cause of acquired heart disease in children in the developed world. TNF-alpha is a pleiotropic inflammatory cytokine elevated during the acute phase of Kawasaki disease. In this study, we report rapid production of TNF-alpha in the peripheral immune system after disease induction in a murine model of Kawasaki disease. This immune response becomes site directed, with migration to the coronary arteries dependent on TNF-alpha-mediated events. Production of TNF-alpha in the heart is coincident with the presence of inflammatory infiltrate at the coronary arteries, which persists during development of aneurysms. More importantly, inflammation and elastin breakdown in the coronary vessels are completely eliminated in the absence of TNF-alpha effector functions. Mice treated with the TNF-alpha-blocking agent etanercept, as well as TNFRI knockout mice, are resistant to development of both coronary arteritis and coronary aneurysm formation. Taken together, TNF-alpha is necessary for the development of coronary artery lesions in an animal model of Kawasaki disease. These findings have important implications for potential new therapeutic interventions in children with Kawasaki disease.     

Recurrent myocardial infarction in a patient with Prinzmetal's angina and normal coronary arteries

A 55-year-old man was referred for the evaluation of frequent chest pain and syncope. While in the hospital, he experienced severe chest pain accompanied by transient ST segment elevation and a slight elevation of cardiac enzyme levels. Multiple coronary arteriograms were recorded at various times during an interval of 2 months. On one occasion, the results were normal; on another occasion, they showed total occlusion of the left anterior descending, diagonal, and circumflex coronary arteries. The occlusion was completely relieved with sublingual nitroglycerin. Because the patient's clinical condition deteriorated rapidly, double aortocoronary saphenous vein bypass was performed to the left anterior descending and circumflex coronary arteries. During the induction of anesthesia, ventricular fibrillation occurred, and the patient died from refractory recurrent fibrillation 4 hours after surgery. Postmortem examination revealed normal coronary arteries, patent vein grafts, and multiple focal areas of recent and old myocardial fibrosis. Thus, it appears that coronary spasm, in the presence of otherwise normal coronary arteries, can produce myocardial infarction with necrosis, and that medical management may provide a more successful method of treating such patients.