Increased factor VIII as an index of vascular injury in cyclosporine nephrotoxicity

Coagulation and Fibrinolysis During the First Year of Immunosuppressive Treatment in Renal Transplantation: Correspondence Between Hypercoagulable State and Steroid Therapy

An increased incidence of thromboembolic complications has been reported after kidney transplantation, and hypercoagulability has been associated with immunosuppressive treatment, specifically with Cyclosporin A. Hypercorticism due to prolonged steroid therapy or to Cushing's disease has been associated with a similar hypercoagulable state and thrombotic risk. The aims of this study were first to evaluate coagulation and fibrinolytic behavior in 27 patients at different times during the first year after renal transplantation and then to compare the same patients' coagulation and fibrinolytic findings 1 month after transplantation with those of a normal control group and a group of Cushing's patients. Compared with normal controls, renal transplant patients and Cushing's patients showed a similar hypercoagulable and hypofibrinolytic state, with a significant shortening in activated partial thromboplastin time and increase in factor VIII-von Willebrand factor complex, tissue plasminogen activator concentration, and plasminogen activator inhibitor activity and concentration. Other test results in the two groups showed no differences. The same abnormalities were present in the renal transplant group for the entire period of study. Our results suggest that a hypercoagulable and hypofibrinolytic state persists almost 1 year after renal transplantation and that these abnormalities are very similar to those present in Cushing's disease. Steroid treatment seems to play a key role in determining thromboembolic risk after renal transplantation. Key Words: Renal transplantation-Hypercoagulable state—von Willebrand factor-Hypofibrinolysis-Plasminogen activator inhibitor-Steroid therapy-Cyclosporin A.

The use of cyclosporine in dermatology: part II

Cyclosporine is highly effective in the treatment of a multitude of dermatoses. Concern over its side effect profile has limited its use in dermatology. Adverse effects are, for the most part, dose dependent and related to duration of therapy. Using the recommended monitoring protocols results in a significant decrease in the incidence of cyclosporine-related toxicities. This article provides a comprehensive review of the pharmacokinetics of cyclosporine, potential drug interactions, adverse effects, and recommendations for monitoring in patients treated with cyclosporine. The use of cyclosporine in pregnancy and in the pediatric population is also addressed.

LEARNING OBJECTIVES

After completing this learning activity, participants should be familiar with the monitoring guidelines of cyclosporine, its contraindications, its possible drug interactions, its adverse effect profile, and its use in pregnancy and the childhood and adolescent populations.

Transplant-associated microangiopathy in patients receiving tacrolimus following allogeneic stem cell transplantation: risk factors and response to treatment

Transplant-associated microangiopathy (TAM) is a life-threatening complication after allogeneic HSCT, particularly with the use of calcineurin inhibitors as post-transplantation immunosuppressive therapy. We report our experience with TAM after HSCT with tacrolimus-based GVHD prophylaxis in a single-center study. Sixty-six of 1219 transplant recipients developed TAM with a cumulative incidence of 5.9%. Risk factors for TAM were female gender, lymphoid malignancy, receipt of a matched unrelated donor, and grade II-IV aGVHD. Most patients had infection and/or active GVHD at the diagnosis of TAM (82%). In the absence of renal dysfunction or encephalopathy, tacrolimus was generally continued, maintaining blood levels within the lower therapeutic range. Sixty-three patients were treated with plasma exchange. The cumulative incidence of response of TAM was 60%. Only 1 patient had a response of TAM without resolution of concomitant infections or GVHD. Six-month survivals were 0% and 50% for TAM nonresponders and responders, respectively. In conclusion, TAM is a common, life-threatening complication of allogeneic hematopoietic transplantation using tacrolimus prophylaxis. Control of TAM generally requires response of associated infections and GVHD. TMA response may occur despite continuation of tacrolimus treatment.

Glomerular vasculopathy after unrelated cord blood transplantation

A 1-year-old boy with hemophagocytic lymphohistiocytosis exhibited proteinuria 1 month after unrelated cord blood cell transplantation, which persisted without hematuria. Laboratory study showed an increase of factor VIII-related antigen and total plasminogen activator inhibitor, suggesting endothelial injury. Histological examination of autopsy materials showed increased mesangial matrices and double-contoured basement membranes, and ultrastructurally, swelling of the endothelial cells and widening of the subendothelial space with mesangial interposition. Thrombosis was not observed at any of the sites. This case may be vasculopathy distinct from thrombotic microangiopathy (TMA) or a variant form of TMA following blood stem cell transplantation (BSCT). This vasculopathy should be considered in the differential diagnosis of proteinuria in the early stages after BSCT.

Current concepts in the diagnosis and management of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura is a multisystem disease characterized by thrombocytopenia, hemolytic anemia, renal failure, fever, and neurologic abnormalities. Plasma exchange has revolutionized the outcome of this entity from a once fatal disease to a disease that potentially is cured or has prolonged remission. The understanding of the pathophysiology of TTP continues to evolve. Recently, investigators showed that a deficiency in a specific plasma protease responsible for cleaving vWf plays a crucial role in the familial form of TTP. This explains in part why patients usually respond to plasma exchange therapy. The identification of a mutation in a specific gene that belongs to the metalloproteinase family located at chromosome 9q34 could have important therapeutic implications. TTP can be induced by certain drugs, especially immunosuppressants, in the setting of bone marrow and solid organ transplantation. This disease also has been described in association with HIV, pregnancy, cancer, and chemotherapy. TTP remains an ideal example of how knowledge about the etiology of a disease can improve therapeutic interventions.

Thrombotic thrombocytopenic purpura following stem cell transplantation

Thrombotic thrombocytopenic purpura (TTP) occurring after stem cell transplantation is poorly understood. The literature is scant and heterogeneous; little is known about the condition's pathogenesis except that it appears to differ from that of classical or de novo TTP. There are no widely agreed diagnostic criteria hence, it is difficult to compare the major findings of the relatively small, single centre series that have been reported. The true incidence is disputed and risk factors have only recently been evaluated. Plasma exchange is commonly employed for the therapy of severe post-transplant TTP but there are no data that support its use. This review summarises the state of knowledge of post-transplant TTP in 2002, addressing all the aforementioned issues and aims to provide the basis for further systematic study of this problematic complication of transplant.

Acute rejection before cytomegalovirus infection enhances von Willebrand factor and soluble VCAM-1 in blood

BACKGROUND

Human cytomegalovirus (HCMV) infections in transplantation patients are associated with vascular endothelial damage. This is reflected by the appearance of cytomegalic endothelial cells (CECs) and noninfected endothelial cells (ECs) in blood. To get more insight in the extent of vascular damage during HCMV infection, we investigated the levels of soluble markers during HCMV infection in relationship to EC levels and also preceding the acute rejection episodes.

METHODS

Of 46 kidney transplant patients, plasma levels of von Willebrand factor (VWF), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble E-selectin (sE-sel) were analyzed during the course of HCMV infection.

RESULTS

Plasma levels of VWF and sVCAM-1 increased twofold during severe HCMV infection. Moreover, the plasma levels of VWF correlated with detectable cytomegalic and noninfected ECs in blood. The kinetics of changes in VWF and ECs (CEC and EC) demonstrated the relationship with HCMV-induced vascular damage. Levels of sICAM-1 and sE-sel in plasma did not significantly change during HCMV infection. Interestingly, the combination of HCMV infection and preceding acute transplant rejection caused the highest increases of VWF and sVCAM-1 plasma levels, reflecting an enhanced susceptibility for endothelial damage at the moment of infection.

CONCLUSION

CMV infection is associated with vascular damage, and the vascular damage during CMV infection is enhanced if patients experienced acute rejection before CMV infection.

Low dose aspirin as prophylaxis against renal-vein thrombosis in renal-transplant recipients

BACKGROUND

Renal-vein thrombosis (RVT) is an infrequent event that accounts for a high proportion of early renal allograft losses, since graft failure secondary to acute irreversible rejection is now relatively rare. The cause of RVT may be related to technical problems, clotting disorders, diabetes, or cyclosporin, but is often difficult to define.

METHODS

This retrospective study was performed to examine the influence of aspirin on the incidence of RVT in cadaveric and living-related renal transplant recipients receiving cyclosporin-based triple immunosuppression. The Oxford Transplant Centre database was used to identify all early (<30 day) non-immunological graft failures and case histories were examined for clinical and pathological evidence of RVT. In July 1991, aspirin (75 mg o.d. starting immediately before and continuing for 1 month post-transplant) was introduced as routine prophylaxis against RVT. Prior to this, aspirin prophylaxis was not used.

RESULTS

In the 6-year period from July 1985 to June 1991, there were 27 cases of RVT in 475 transplants (5.6%). In the subsequent 6-year period, there were six cases of RVT in 480 transplants (1.2%) (P:<0.01).

CONCLUSION

Although not abolished, this indicates a significant reduction in the incidence of RVT with the addition of low-dose aspirin.

Smooth muscle-specific actin levels in the urine of renal transplant recipients: correlation with cyclosporine or tacrolimus nephrotoxicity

Cyclosporine A (CSA) and tacrolimus (FK506) are powerful immunosuppressive agents that have proven useful for antirejection therapy in patients with solid organ transplants, including kidney. However, both drugs are nephrotoxic, each producing similar histological patterns of injury to renal tubules and preglomerular arterioles, and this toxicity is a major cause of renal allograft dysfunction. A renal transplant biopsy presently represents the most reliable means of diagnosing nephrotoxicity caused by CSA or tacrolimus and distinguishing it from acute rejection. Because CSA and tacrolimus nephrotoxicity often involve arteriolar smooth muscle, whereas vascular smooth muscle is rarely involved in acute rejection, we investigated if the appearance of a smooth muscle-specific isoform of alpha-actin (SMA) in the urine of renal transplant recipients about to undergo a biopsy for graft dysfunction correlated with biopsy evidence of CSA or tacrolimus toxicity. Eighty-nine urine samples from 61 patients, plus 6 samples from healthy control subjects, were analyzed in a blinded manner by enzyme-linked immunosorbent assay using a specific anti-SMA monoclonal antibody. For the patient samples, the results of these assays were then correlated with the biopsy findings. Those 40 cases in which the biopsy showed evidence of CSA or tacrolimus nephrotoxicity had a significantly (P < 0.01) greater SMA level in the corresponding urine samples (0.089 +/- 0.126 microgram/mL; mean +/- SD) than the 49 cases without toxicity (0.018 +/- 0.027 microgram/mL) or 6 control subjects (0.003 +/- 0.007 microgram/mL), although there was considerable overlap of SMA values among these groups. The greatest SMA levels were seen in patients with CSA or tacrolimus nephrotoxicity that was likely to be relatively acute, namely those with thrombotic microangiopathy and those without previous biopsy evidence of toxicity. SMA levels correlated significantly with the estimated severity of arteriolopathy on biopsy. In patients with tubular but not arteriolar lesions of CSA or tacrolimus toxicity, the mean SMA level was not significantly greater than that in patients without toxicity. Urine SMA levels in patients with a biopsy specimen showing acute rejection were not significantly different from those in patients without rejection, and there was no correlation between urine SMA level and severity of rejection. Whereas the degree of overlap of SMA levels in patients with and without nephrotoxicity was far too great to consider this assay as a potential alternative to renal transplant biopsy for the diagnosis of nephrotoxicity, the assay may have potential as a marker for active arteriolar injury in renal transplant recipients and other patients receiving CSA or tacrolimus therapy.

von Willebrand Factor Proteolysis Is Deficient in Classic, but not in Bone Marrow Transplantation–Associated, Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura (TTP) after bone marrow transplantation (BMT) differs from classic TTP in its clinical course and therapy. A characteristic of classic TTP is the inhibition of a plasma protease that specifically cleaves von Willebrand factor (vWF), thus reducing its multimeric size. We investigated whether this protease was also inhibited in BMT-associated TTP. Plasma from patients with classic or BMT-associated TTP was incubated with recombinant vWF R834Q, a vWF mutant with enhanced sensitivity to the protease. The proteolysis of vWF multimers was analyzed and quantified on Western blot. Metalloprotease activity was strongly inhibited in the classic TTP patient group. However, metalloprotease activity was normal in the BMT-associated TTP patient group. The difference in activity between the two patient groups was highly significant (P = .0016). The results indicate that the etiologies of classic and BMT-associated TTP are indeed different and provide an explanation for the lack of success of plasma exchange in BMT-associated TTP.

von Willebrand Factor Proteolysis Is Deficient in Classic, but not in Bone Marrow Transplantation–Associated, Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura (TTP) after bone marrow transplantation (BMT) differs from classic TTP in its clinical course and therapy. A characteristic of classic TTP is the inhibition of a plasma protease that specifically cleaves von Willebrand factor (vWF), thus reducing its multimeric size. We investigated whether this protease was also inhibited in BMT-associated TTP. Plasma from patients with classic or BMT-associated TTP was incubated with recombinant vWF R834Q, a vWF mutant with enhanced sensitivity to the protease. The proteolysis of vWF multimers was analyzed and quantified on Western blot. Metalloprotease activity was strongly inhibited in the classic TTP patient group. However, metalloprotease activity was normal in the BMT-associated TTP patient group. The difference in activity between the two patient groups was highly significant (P = .0016). The results indicate that the etiologies of classic and BMT-associated TTP are indeed different and provide an explanation for the lack of success of plasma exchange in BMT-associated TTP.

Oxidative stress in cyclosporin and azathioprine treated renal transplant patients

The major cause of death following transplantation is cardiovascular disease. Among the many processes involved in atherogenesis, oxidative stress and modification of low density lipoprotein has been assigned a major role. This in turn may be affected by the immunosuppressive regime used. We studied oxidative stress in 40 renal transplant patients receiving two different immunosuppressive regimens (20 on cyclosporin, 20 on azathioprine/prednisolone), and 19 normal controls. Changes in lipid peroxidation (assessed as thiobarbituric acid reacting substances, TBARS), antioxidant enzyme activities (glutathione reductase GSHPx, glutathione peroxidase GSHPx and superoxide dismutase SOD) vitamin E and antioxidant associated trace metals (selenium, copper, zinc) were studied. Alteration of erythrocyte membrane fluidity was examined using the fluorescent probe 1,6 diphenyl-1,3,5-hexatriene (DPH). Both transplant groups showed no difference in TBARS, lipid standardised vitamin E, copper or selenium compared to controls. Zinc was significantly increased in both the cyclosporin and azathioprine groups compared to controls (P < 0.05). SOD was reduced in both transplant groups compared to controls (P < 0.001). GSHPx was elevated in both groups compared to controls but only reached significance in the azathioprine treated group (P < 0.005). GSHRx was slightly elevated in both transplant groups but did not reach significance. Erythrocyte membrane anisotropy was decreased in the cyclosporin treated group (P < 0.05). There was no difference in the azathioprine group compared to controls. The present results suggest an adaptive response to increased oxidative stress in both transplant groups sufficient to minimise markers of oxidative stress (TBARS and anisotropy). The results also suggest no significant difference between the two immunosuppressive regimes with regard to oxidative stress.

Associations between carotid atherosclerosis and high factor VIII activity, dyslipidemia, and hypertension

BACKGROUND AND PURPOSE

A subsample of 147 Chinese subjects from a population-based study of cardiovascular diseases (Cardiovascular Disease Risk Factor Two-Township Study) participated in an ancillary study on extracranial carotid color duplex ultrasonography that aimed to assess the relations of coagulation factors to stroke and carotid atherosclerosis.

METHODS

Logistic models were used to study the associations between cardiovascular disease risk factors and stroke/carotid atherosclerosis, controlling for the effects of age and sex.

RESULTS

Stroke was significantly associated with hypertension and high values of plasma glucose but not with fibrinogen, factor VIIc, or factor VIIIc. Carotid plaques identified in this study were mostly mild and moderate. The presence of these mild and moderate carotid plaques was significantly associated with high values of factor VIII activity, hypercholesterolemia, hypertriglyceridemia, and hypertension. The highest tertile of factor VIIIc (> 1.53) was associated with an odds ratio of 3.35 for carotid atherosclerosis when compared with the lowest tertile (< 1.20). A multiple logistic regression including all significant risk factors showed that the degree of association between factor VIIIc and atherosclerosis was attenuated to an odds ratio of 2.65 (P = .061).

CONCLUSIONS

In the present study, the roles of hypertension, hypercholesterolemia, and hypertriglyceridemia have been implicated in the pathogenesis of carotid atherosclerosis, and roles for hypertension and hyperglycemia in stroke were indicated. A positive association between factor VIIIc and carotid atherosclerosis in this Chinese population was found. Whether this association is independent of the effect of other cardiovascular risk factors awaits further study.

The coagulo-lytic system and endothelial function in cyclosporine-treated kidney allograft recipients

Since thromboembolic complications in transplanted patients are generally attributed to combined abnormalities in platelets and coagulo-lytic system, some hemostatic parameters tPA (tissue plasmogin activator):Ag and activity, its inhibitor-PAIAg and activity, tPA/PAI, thrombin-antithrombin (TAT) and plasmin-antiplasmin complexes (PAP), urokinase-uPA, euglobulin clot lysis time-ECLT, fibrinogen, plasminogen, protein C activity, D-dimer, prothrombin fragments1+2 (F1+2), fibrin monomers, fibronectin, lipoprotein-a, and von Willebrand factor(vWF), were evaluated using commercially available kits. The studies were performed on kidney transplant recipients treated with CsA, azathioprine and prednisone (n=21), and healthy volunteers (n=21). ECLT was significantly prolonged in kidney transplant recipients together with a rise in F1+2,lipoprotein-a, fibrinogen, fibronectin, and vWF when compared with controls. The TPA level was lower, whereas the PAI level was higher in kidney transplant recipients when compared with controls. In conclusion, CsA-treated kidney transplant recipients show evidence of pronounced impairment in fibrinolysis and endothelial damage in comparison with healthy volunteers.

Peripheral serotonergic system in uremia

Several data suggest that platelet-derived serotonin (5-HT), previously classified as a trivial modulator of blood-borne cardiovascular disease (1), may play a decisive role in various pathological processes, resulting from abnormal platelet-vessel wall interactions (2). Following platelet activation upon a contact with a damaged vessel wall, 5-HT, released from platelets upon the activation of 5-HT2 receptors, may amplify the action of other agents on vascular smooth muscle cells and platelets (3,4). Platelets play a unique role in 5-HT metabolism: they take it up, store in their dense granules and release upon stimulation. Platelet dysfunction, alteration in platelet count, their consumption and turnover are common in renal diseases (5). Storage pool deficiency regarding 5-HT and ADP was reported in renal failure (6). Previously we reported that 5HT2 receptor blockers may serve as potent antiplatelet drugs in uremic patients, which are prone to thrombotic complications (7,8). Up to date there have been a few reports dealing predominantly with 5-HT levels in renal patients. Thus, we focused on peripheral serotonergic mechanisms including 5-HT uptake and release and kinetics of its uptake in uremic patients.

Cyclosporine-induced detachment of vascular endothelial cells initiates the intrinsic coagulation system in plasma and whole blood

Cyclosporine A (CsA) is supposed to alter the metabolism of vascular endothelial cells, leading to a prothrombotic state. We examined by which mechanism human umbilical vein endothelial cells (HUVECs) treated with CsA would promote coagulation in human plasma and in whole blood. Treatment of HUVECs with CsA at concentrations clinically used led to dose-dependent cell detachment, with the subsequent exposure of the highly procoagulant connective tissue. As determined by scanning electron microscopy, cell counting of detached and adherent cells, and antigenic measurement of collagen exposure, HUVECs treated with 0.4 micrograms/ml CsA (or more) for 4 days exhibited significant amounts of subendothelial areas. On CsA-treated HUVEC monolayers, the clotting time of recalcified citrated platelet-rich plasma (PRP), but not platelet-poor plasma (PPP), was dose-dependently shortened. Likewise, the onset of thrombin generation was significantly earlier. Except at a high concentration of 8.0 micrograms/ml CsA, there was no procoagulant effect when PPP was used. To investigate CsA-treated HUVECs in whole blood, cells were cultivated on globular microcarriers and were incubated with nonanticoagulated whole blood. When untreated cells were used, generation of factor Xa, thrombin, and kallikrein was completely suppressed for 30 minutes. HUVEC beads treated with 0.4 and 0.8 micrograms/ml CsA, however, led to a dose-dependent generation of all three coagulation factors, with peak values at 2.5 to 5 minutes. Extrinsic activation was excluded, since CsA treatment did not induce tissue factor activity in HUVECs. Furthermore, the thrombomodulin activity of HUVECs w as not altered by CsA. In conclusion, treatment of HUVECs with CsA for 4 days at concentrations clinically used leads to the exposure of subendothelial areas that induce activation of the intrinsic coagulation in recalcified PRP and nonanticoagulated whole blood.

Thrombotic microangiopathies associated with drugs and bone marrow transplantation

This type of thrombotic microangiopathy more commonly resembles the hemolytic-uremic syndrome (HUS) than thrombotic thrombocytopenic purpura (TTP). The syndrome has been associated with the use of cyclosporin, mitomycin C, combinations of other chemotherapeutic and immunosuppressive agents, and total body irradiation. Endothelial cell injury and von Willebrand factor may be involved in pathogenesis of the intravascular platelet aggregation and tissue (especially renal) ischemia and infarction that characterize the entity. The most effective therapy for thrombotic microangiopathy associated with drugs and bone marrow transplantation has not been determined.

Cyclosporine-induced hypertension after transplantation

OBJECTIVE

To describe the features and mechanisms of posttransplantation hypertension and suggest appropriate management of the disorder.

DESIGN

We review our own experience and reports from the literature on hypertension in cyclosporine A (CSA)-treated transplant recipients.

RESULTS

Soon after immunosuppression with CSA and corticosteroids, hypertension develops in most patients who undergo transplantation. The blood pressure increases, which are usually moderate, occur universally because of increased peripheral vascular resistance. Disturbances in circadian patterns of blood pressure lead to loss of the normal nocturnal decline, a feature that magnifies hypertensive target effects. Changes in blood pressure sometimes are severe and associated with rapidly developing target injury, including intracranial hemorrhage, left ventricular hypertrophy, and microangiopathic hemolysis. The complex mechanisms that underlie this disorder include alterations in vascular reactivity that cause widespread vasoconstriction. Vascular effects in the kidney lead to reduced glomerular filtration and impaired sodium excretion. Many of these changes affect local regulation of vascular tone, including stimulation of endothelin and suppression of vasodilating prostaglandins. Effective therapy includes use of vasodilating agents, often calcium channel blocking drugs. Caution must be exercised to avoid interfering with the disposition of CSA or aggravating adverse effects relative to kidney and electrolyte homeostasis.

CONCLUSION

Recognition and treatment of CSA-induced hypertension and vascular injury are important elements in managing the transplant recipient.

Serotonergic measures in cyclosporine A treated rats

Whole blood and plasma serotonin (5-HT), its major metabolite--5-hydroxyindoleacetic acid (5-HIAA), renal cortical blood flow, serum creatinine and whole blood cyclosporine A (CyA) levels were investigated in rats administered with CyA at a dose of 5 mg/kg b.w. or 10 mg/kg b.w. for 14 consecutive days. Serum creatinine remained unaltered during CyA treatment and no apparent changes in excised kidneys were found. Dose-dependent increases in whole blood and plasma 5-HT as well as whole blood 5-HIAA levels were observed. Renal cortical blood flow declined significantly and correlated inversely with whole blood 5-HT and 5-HIAA as well as with plasma 5-HT. Whole blood 5-HT was positively related to whole blood CyA levels. Taking all these data into account and considering the fact that 5-HT is a potent vasoconstrictor, a possible role of this amine in the pathogenesis of renal ischemia during CyA administration is suggested.

Fibrinolysis and serotonin under cyclosporine A treatment in renal transplant recipients

Cyclosporine A (CyA), a potent immunosuppressive drug, has been used in renal transplant recipients with increasing frequency since 1982. Despite its efficacy, CyA therapy has been associated with an increased incidence of thromboembolic complications. This has been attributed to increased thromboxane production, reduced prostacyclin synthesis and increased platelet aggregability. The coagulation system is also altered in CyA-treated patients and some of these changes would favor thrombosis. Increased fibrinogen and FVII:C levels have also been associated with an enhanced risk of thrombosis. In contrast, CyA therapy was reported to increase the levels of antithrombin III and protein C, two proteins known to protect against venous thromboembolism. However, the possible effect of CyA on the fibrinolytic system has not been thoroughly investigated and rather confusing data have been reported concerning both enhancement and suppression of fibrinolysis. Serotonin (5-hydroxytryptamine, 5-HT) may play a role in hemostasis and platelet/vessel wall interactions. It may facilitate platelet thrombus formation by potentiating the aggregatory response to other agents such as ADP, collagen or epinephrine and by causing vasoconstriction. Taking all these data into consideration we have measured some fibrinolytic parameters, whole blood and plasma serotonin concentration in cyclosporine A- and non-cyclosporine A-treated kidney transplant recipients.

The paraproteins in systemic capillary leak syndrome

Systemic capillary leak syndrome (SCLS) is a rare disease characterized by episodes of collapse due to rapid transfer of considerable volumes of plasma from the intravascular to the extravascular compartment. The pathogenesis of this disease is unknown. The diagnosis is made largely on clinical grounds, and investigations are unhelpful. The only consistent abnormality is that an IgG paraprotein is found in most patients, raising the possibility that the paraprotein may be involved in the pathogenesis of the disease. Reduction of the paraprotein level in our patient was associated with remission. Blood samples from three SCLS patients and one probable SCLS have been studied. All patients had monoclonal IgG paraproteins. The purified paraproteins were all of IgG1 subclass and had kappa light chains. However, they differed in size and charge. Antibodies against each of the paraproteins were raised in rabbits. Affinity-purified anti-idiotypic antibodies were tested for cross-reactivity against the other paraproteins using immunoblotting and Ouchterlony assay. These assays showed that the anti-idiotypic antibodies reacted only with the immunizing paraprotein and not with any of the other paraproteins, i.e. that the paraproteins do not share a common idiotype. Paraproteins did not bind to cultured endothelial cells, either unactivated or following activation with interferon-gamma (IFN-gamma), IL-2 or IL-6. In addition, we were unable to demonstrate any cytotoxicity towards cultured human endothelial cells by paraprotein alone, or in the presence of neutrophils (pronounced neutrophilia being a feature of attacks). The relationship between the paraproteins and the disease remains unclear. It is likely that additional, as yet unidentified, factors are required for the paraprotein to lead to capillary leak.

De novo hypertension after liver transplantation

Hypertension develops in most patients after transplantation when immunosuppression is based on cyclosporine and prednisone. The pathogenesis appears to be multifactorial but involves rapidly rising vasoconstrictor tone in renal and systemic vascular beds. Much of this tone reflects abnormal vascular function, characterized by impaired prostacyclin and EDRF effects, in conjunction with increased vasoconstriction due to endothelin and possibly other factors. Effective management of the transplant recipient depends on preventing excessive vasoconstriction, usually with calcium channel blocking agents.

Pharmacodynamic monitoring of cyclosporin

The efficacy of cyclosporin as an immunosuppressive agent is largely based on clinical indicators such as graft survival, rejection or nephrotoxicity. Therapeutic monitoring is necessary to evaluate the efficacy of cyclosporin therapy. The most widely used method for monitoring cyclosporin therapy is the measurement of predose through blood concentrations of the drug. The relationship of a single or multiple blood cyclosporin concentration to slowly evolving outcomes is difficult to establish. Some investigators have found a good correlation between cyclosporin trough concentrations on the one hand and cyclosporin toxicity and rejection on the other, but others have not. Therapeutic monitoring of cyclosporin may be enhanced using some biological assays for immunosuppression (pharmacodynamic monitoring) in addition to cyclosporin trough concentrations (pharmacokinetic monitoring). However, direct monitoring of the immune response to cyclosporin therapy using a clinically applicable biological assay is difficult. Some pharmacodynamic parameters have been suggested as biological markers in the clinical monitoring of cyclosporin.

Circulating thrombomodulin as a novel endothelial cell marker: comparison of its behavior with von Willebrand factor and tissue-type plasminogen activator

Circulating thrombomodulin is a novel endothelial cell marker, which may reflect the endothelial injury. Plasma levels of thrombomodulin were quantitated by an enzyme-linked immunosorbent assay (ELISA) in patients with hematological malignancies, liver disease, diabetes mellitus, collagen disease, thrombotic disease, and disseminated intravascular coagulation (DIC), and the thrombomodulin values were compared with those of von Willebrand factor antigen (vWf:Ag) and tissue-type plasminogen activator (t-PA) which are released from stimulated or damaged endothelial cells. The mean plasma concentrations of thrombomodulin in these disease states were elevated as compared with healthy subjects. A relatively high mean thrombomodulin level was observed in DIC, liver disease, and collagen disease. Abnormally high thrombomodulin values (greater than normal mean value + 3 SD) were found in 32.3% of patients with hematological malignancies, 57.7% of patients with liver disease, 39.3% of patients with diabetes mellitus, 30.0% of patients with collagen disease, 23.1% of patients with thrombotic disease, and 69.0% of patients with DIC. Plasma concentrations of both vWf:Ag and t-PA were also elevated in these patients. On the whole, the plasma thrombomodulin concentration was positively correlated with vWf:Ag (r = 0.441, P less than 0.001) and t-PA (r = 0.398, P less than 0.001). These findings indicate that the elevation of plasma thrombomodulin is frequently seen in a variety of diseases and circulating thrombomodulin is possibly useful for evaluating the endothelial damage in selected disease states.

Circulating thrombomodulin in thrombotic thrombocytopenic purpura

Endothelial cell injury is thought to be one of the causative factors in thrombotic thrombocytopenic purpura (TTP). A novel index of endothelial injury, plasma thrombomodulin, was measured in 13 patients with acute TTP. The mean plasma concentration of thrombomodulin was elevated in patients with TTP (34.23 +/- 19.08 ng/ml) as compared with healthy subjects (16.99 +/- 2.63 ng/ml, P less than 0.001). Eight (61.5%) of 13 patients had high thrombomodulin values. Markedly elevated thrombomodulin levels were observed in TTP patients who had suffered from systemic lupus erythematosus, in whom plasma thrombomodulin was still elevated when they achieved remission. Five of these 13 patients with TTP had normal plasma levels of thrombomodulin. In addition, the plasma thrombomodulin concentrations were correlated well with von Willebrand factor antigen and tissue-type plasminogen activator antigen levels, both of which are released from stimulated or damaged endothelial cells. No difference was found in plasma thrombomodulin levels between patients who achieved remission and who did not. These findings suggest that the magnitude of the endothelial damage in TTP is variable among patients and that plasma thrombomodulin has limited clinical relevance to the severity of TTP.

Cyclosporin treatment does not impair the release of nitric oxide in human coronary arteries

OBJECTIVE

It has been hypothesised that compromised endothelial function can contribute to the toxic manifestations associated with cyclosporin therapy. In vitro animal studies have implicated inhibition of release of the endothelium derived relaxing factor, nitric oxide; however, this has not been investigated in human tissue. The present study investigated the effect of cyclosporin A on nitric oxide release in human coronary arteries.

DESIGN

Study of in vitro organ bath preparations and in vivo angiographic measurements in the coronary circulation.

PATIENTS

For the in vitro experiments coronary arteries were harvested from the excised hearts of 10 patients requiring transplantation for reasons other than ischaemic heart disease. Three of these patients were being re-transplanted for obliterative bronchiolitis and had been receiving cyclosporin for a mean of 22 months. The in vivo study was performed on a group of 12 cardiac transplant recipients who were clinically well 1-5 years postoperatively and were not undergoing allograft rejection at the time of assessment.

RESULTS

Isolated vessel segments in vitro relaxed in a dose dependent manner in response to substance P (10(-11)-10(-7) mol/l). The maximum response was 76.6 (7.4)% of the response to 1 microgram/ml glyceryl trinitrate. Incubation with 1000 and 2000 ng/ml cyclosporin reduced the response to 63.0 (11.5)% and 62.2 (11.1)% respectively; this was not statistically significant. In segments taken from the explanted hearts of three patients requiring re-transplantation, the mean maximum response was 78.0 (11.0)% and there was no correlation between maximum response in segments from each patient and the duration of cyclosporin therapy. The effect of intracoronary substance P in 12 cardiac transplant recipients was also examined (mean cyclosporin blood concentration 228.9 (42.8) ng/ml). The mean maximum dilatations measured as the percentage diameter change induced by substance P and isosorbide dinitrate were 22.1 (3.2)% and 26.0 (2.5)% respectively. There was no correlation between the degree of endothelium mediated vasodilatation in response to substance P and cyclosporin concentration.

CONCLUSIONS

The nitric oxide response was preserved in the coronary arteries of patients exposed to cyclosporin. The mechanisms that initiate cyclosporin associated toxicity remain to be elucidated.

Cyclosporine-induced synthesis of endothelin by cultured human endothelial cells

Endothelin (ET), a peptide synthesized by endothelial cells (EC), causes a decreased renal blood flow and glomerular filtration rate and an increased mean arterial pressure when infused in animals. In tissue culture, ET causes smooth muscle cell (SMC) proliferation and contraction by influx of extracellular calcium, which is inhibited by calcium channel antagonists. Infusion of cyclosporine (CSA) hemodynamically parallels ET action, and knowing that CSA effects EC, we hypothesize that the vasoconstrictive effects of CSA are a result of ET synthesis by EC. Varying concentrations of CSA were incubated with EC resulting in ET present in the supernatants in a dose-dependent manner peaking at 75% above basal activity. Coincubation of either cremophor alone or cycloheximide with CSA resulted in minimal ET present in the EC supernatants (P less than 0.01 each). Incubation of conditioned media from CSA-treated EC with SMC caused proliferation at 114% above basal activity, which did not occur in the presence of CSA alone (P less than 0.01). This activity is specifically inhibited in the presence of an anti-ET antibody or nonspecifically in the presence of calcium channel antagonists (P less than 0.01 each). Therefore, CSA stimulates EC synthesis of ET which in turn causes SMC proliferation. This action is inhibited by the coincubation of a specific antibody to ET or a calcium channel antagonist. These findings may help in the understanding of CSA-induced hypertension and vasculopathy.

Arteriolosclerosis of the human renal allograft: morphology, origin, life history and relationship to cyclosporine therapy

In the decade 1979-1988, 658 biopsies were collected from 568 cadaveric renal allografts. In 118 grafts a non-proliferative insudative vasculopathy (IVA) was found in afferent vessels. Immunosuppression was based on azathioprine (AZA) or on cyclosporin A (CsA), from 1983. The prevalence and extent of IVA has increased significantly since 1984. Light microscopy showed fibrinoid and hyaline masses of varying extent; transmural insudative "knobs", intimal oedema with metachromasia, and microthrombosis were also seen with CsA. The ultrastructure of the insudates was unremarkable but CsA grafts displayed early oedema and hypergranulation of endothelial cells with a disarray of smooth muscle cell (SMC) microfibrils, and pronounced degenerative changes of SMC. Rebiopsy showed stationary IVA in AZA grafts and progression in one-half of CsA-treated patients. Nephrectomy specimens revealed, however, a marked predominance of late rejection endarteritis; in only 3 cases was IVA and/or microthrombosis the possible cause of nephrectomy. The mean donor age was higher in severe IVA in CsA grafts and the mean post-transplantation interval at the time of diagnosis of IVA was significantly shorter in CsA-treated patients. No important differences in cumulative graft survival were seen between grafts with absent, moderate or severe IVA. Unused cadaveric donors' kidneys of comparable age exhibited normal arterioles or a slight focal insudative or hyaline lesion.

Protective effect of allopurinol and superoxide dismutase in renal isografts in cyclosporin A-treated rats

Acute tubular necrosis (ATN) after renal transplantation is related to the duration of warm and cold ischemia and leads to temporary or permanent impairment of graft function. An increased incidence of ATN has been reported since the introduction of cyclosporin A. Kidney damage resulting from hypothermic storage is generated in part during reperfusion rather than during ischemia itself. Potential mediators of the reperfusion injury are oxygen-derived free radicals. Therefore, the influence of two oxygen radical antagonists, allopurinol and superoxide dismutase, was evaluated in syngeneic rat kidney transplantation with and without concurrent administration of cyclosporin A. At 15 h cold ischemia, 28-day survival increased from 8% (no treatment) to 22% (superoxide dismutase), 33% (superoxide dismutase and allopurinol), and 73% (allopurinol). Cyclosporin A cotreatment (10 mg/kg over 14 days) resulted in survival rates of 0%, 25%, 17%, and 50% for the respective treatment groups. The results of serum creatinine values and morphological evaluation of biopsies paralleled the survival rates. Cyclosporin A nephrotoxicity was evidenced by significant serum creatinine elevations throughout the 28-day period of observation. In conclusion, allopurinol significantly protects syngeneic rat kidney transplants against a critical duration of cold ischemia. Under the conditions of this experiment, allopurinol was clearly superior to superoxide dismutase treatment. Cyclosporin A nephrotoxicity was, however, not ablated by the oxygen radical antagonists employed.

Autoantibodies to endothelial cells and neutrophil cytoplasmic antigens in systemic vasculitis

The interaction of circulating autoantibodies with the endothelium may be an important mechanism in the pathogenesis of systemic vasculitis. In a prospective study, we looked for circulating antiendothelial cell autoantibodies (AECA) and anti-neutrophil cytoplasm autoantibodies (ANCA) in 80 patients with suspected systemic vasculitis. AECA were measured using an isotype-specific cellular ELISA incorporating human umbilical vein endothelial cells. ANCA activity was determined by indirect immunofluorescence and radioimmunoassay. Sequential studies were performed on sera from four cases with dual positivity, where autoantibody binding was compared with von Willebrand factor (vWF) concentration and disease activity. IgG AECA were significantly higher in the 27 ANCA-positive sera as compared with normal controls (P = 0.027) with IgG (P = 0.009) and IgA (P = 0.046) AECA isotypes correlating with ANCA positivity; in contrast, no differences were found between AECA levels in the ANCA-negative sera and the normal controls. Cross-inhibition studies pointed to the co-existence of two autoantibody populations. An association between autoantibody binding, disease activity and vWF concentration was found for both ANCA and AECA. Some patients with systemic vasculitis have detectable AECA that recognize different epitopes to ANCA and like ANCA, their titre correlates with disease activity and thus they may have a pathogenetic role in these conditions.

The pathophysiology of Sandimmune (cyclosporine) in man and animals

Part II: The side-effects of Sandimmune that have also been observed clinically include hepatic dysfunction, glucose intolerance, thrombo-embolic complications and nervous system disorders. To determine the cause and significance of such effects, the actions of Sandimmune on the liver, the pancreas, on hematostasis and the nervous system were examined. Comparisons were made between animal and human data obtained in vivo and in vitro, and the clinical setting under which the side-effects occur was analyzed. The actions of Sandimmune on the liver seem to reflect mostly a cholestasis with a small depression in protein synthesis and a mild disturbance in lipid metabolism of uncertain origin. The action of Sandimmune on the pancreas suggests insulin resistance and possibly a secretory disturbance, with no evidence for depressed insulin synthesis, except in animals at high doses. Sandimmune does not seem to promote thromboembolism in man, although fibrinolysis may be depressed and platelet aggregation can be enhanced. The effects of Sandimmune on the nervous system are unclear, for tremor is common but of uncertain origin, whereas seizures and encephalopathy are rare and invariably associated with other risk factors.

Renal side-effects of cyclosporin A with special reference to autoimmune diseases

At therapeutic drug levels, the functional changes which occur are a reduction of glomerular filtration rate and renal plasma flow. At higher doses, morphological changes develop which may result, particularly in severe cases, in acute or chronic renal failure. The threshold for the development of irreversible vascular-interstitial lesions mainly depends on the increment of serum creatinine, age and drug dosage or drug blood level. Based on the experience with cyclosporin A (CyA), the following recommendations have been made for its clinical use, especially in patients with autoimmune diseases. The initial dose should not exceed 5 mg/kg body weight and the dose should be reduced if blood CyA levels are over 250 ng/ml; in addition, a dose reduction is recommended if serum creatinine values exceed 30% of pre-treatment values or if other signs of CyA toxicity, such as hepatotoxicity or hypertension, are found. Strict adherence to these suggestions should allow treatment of patients for prolonged periods without irreversible morphological lesions.

Spontaneous rupture of renal allografts: the importance of renal vein thrombosis in the cyclosporin era

Spontaneous renal allograft rupture occurring within 14 days of transplantation occurred in 15 patients from 791 consecutive transplants. In each of eight patients treated with azathioprine and prednisolone there was pathological evidence of rejection and only two patients had thrombosis of the renal vein. Of the seven cases occurring in patients treated with triple therapy regimen (low dose cyclosporin, prednisolone and azathioprine), histological evidence of rejection was present in only three cases, but renal vein thrombosis was found in all seven. Spontaneous rupture of a transplanted kidney, a relatively uncommon complication, is more likely to be due to renal vein thrombosis than to rejection in the cyclosporin era.

Cyclosporin therapy in vivo attenuates the response to vasodilators in the isolated perfused kidney of the rabbit

1. The endothelium releases a number of vasoactive compounds, including the vasodilator prostaglandins, prostacyclin (PGI2) and prostaglandin E2 (PGE2) and endothelium-derived relaxing factor (EDRF), which play an important role in the regulation of vascular tone in the microcirculation. Nephrotoxicity is the major complication of cyclosporin (CS) therapy and is related to an increase in intrarenal vascular tone. Endothelial cell generation of PGI2 is inhibited by CS although this cannot fully explain the changes in vascular tone observed. We have investigated the possibility that EDRF-dependent vasodilatation is also affected by CS therapy in vivo. 2. CS nephrotoxicity was induced in rabbits with CS (15 mg kg-1 per day s.c. for 20 days (n = 6]; 6 rabbits were given CS vehicle (Veh) and 9 animals were studied without any treatment. Creatinine clearance fell significantly during treatment in the CS-treated rabbits (11.78 +/- 1.5 ml min-1, mean +/- s.e. mean, to 7.79 +/- 1.2 after 20 days treatment) but did not change in the vehicle-treated animals. 3. The responses to the endothelium-dependent (acetylcholine (ACh] and endothelium-independent (nitroprusside (NP) and PGI2) vasodilators were assessed in indomethacin-treated isolated perfused kidneys (IPKs) from untreated, CS- and Veh-treated animals. Vascular tone was induced with a constant infusion of noradrenaline 150 nM and the perfusion rate adjusted to produce a perfusion pressure of 90 mmHg. Perfusate flow rate (22.3 +/- 4.6 vs 20.4 +/- 3.1 ml min-1) and glomerular filtration rate (2.04 +/- 0.37 vs 1.88 +/- 0.16 nl min-1) did not differ between IPKs from CS- and Veh-treated animals. 4. The vasodilator response to ACh was reduced in the kidneys from CS-treated animals compared with those from untreated and Veh-treated animals (mean reduction 35.3 + 2.3% compared with Veh) as were the responses to both NP (42.8 + 3.6%) and PGI2 (27.7 + 7.4%). 5. This suggests that CS nephrotoxicity is not mediated via an effect on endothelium-dependent responses and that it is more likely that CS has a direct effect on vascular smooth muscle.

Gout in the heart transplant recipient: physiologic puzzle and therapeutic challenge

PURPOSE

Hyperuricemia and gouty arthritis have been associated with cyclosporine use in renal transplant recipients. Patients requiring heart or heart-lung transplantation may have additional risk factors for the development of gout, yet it has not previously been described in this population. We share herein our clinical experience with gouty arthritis in six heart transplant recipients.

PATIENTS AND METHODS

During a one-year period, six hospitalized male heart transplant patients were seen in consultation for gouty arthritis. Five were subsequently followed for gout as outpatients; the sixth died within six months. Management included trials of nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, allopurinol, and intra-articular steroid injections, as well as attempts to minimize cyclosporine nephrotoxicity.

RESULTS

Three patients had gout in remission at time of transplant surgery, and three others developed gout for the first time two to 45 months after transplantation. Following transplant surgery, both pre-existing and new-onset gout appeared to exhibit an accelerated course, with unusually rapid development of chronic polyarticular disease and tophi in four of the five patients followed for more than six months. Peak serum uric acid levels ranged from 11.0 mg/dL to 16.5 mg/dL. NSAIDs produced reversible renal insufficiency in four patients. Gout-related infections occurred in three patients, one of whom died.

CONCLUSION

Acute gouty arthritis may occur in the heart transplant recipient despite concomitant use of immunosuppressive drugs. Cyclosporine, with its attendant hypertension and nephrotoxicity, appears to be the major risk factor for hyperuricemia in this setting, leading to the accelerated development of tophi and chronic polyarthritis. Management is complicated by the patients' renal insufficiency and propensity to infection, as well as by interaction with transplant-related medications. Prevention of hyperuricemia by minimizing cyclosporine nephrotoxicity appears to be the best management strategy, with judicious use of allopurinol for those patients in whom this preventive approach fails.

Vascular endothelial cell function and ultrastructure in thrombotic microangiopathy following allogeneic bone marrow transplantation

We report studies on vascular endothelial function and ultrastructure in 2 cases of fatal cyclosporin (CS)-associated thrombotic microangiography following allogeneic bone marrow transplantation (BMT). Spontaneous vascular release of prostacyclin (PGI2) from a vein sample ex vivo was absent, and scanning electron microscopy (SEM) showed surface changes indicative of vascular endothelial damage (case 1). PGI2 release from cultured human umbilical vein endothelial cells incubated with patients' serum in vitro was normal in both cases. Plasma von Willebrand factor (vWF) antigen and ristocetin cofactor activity levels were raised in both patients, 5.06 and 7.02 (case 1) and 3.60 and 2.01 (case 2) (normal ranges 0.59-1.57 and 0.42-1.74 U/ml), respectively, but multimer patterns were normal. The SEM appearances coupled with the absent PGI2 release and raised vWF levels suggest that vascular endothelial damage is central to the pathogenic process in thrombotic microangiopathy following allogeneic BMT but the mechanisms appear to be distinct from those in the haemolytic uraemic syndrome and de novo thrombotic thrombocytopenic purpura. The precise role of CS in this process remains to be identified.

Renal vascular and thrombotic effects of cyclosporine

Cyclosporine A (CyA) given to prevent xenograft rejection induces renal function impairment. In the last few years many studies have been devoted to understanding the mechanism(s) of CyA-induced renal insufficiency. In humans, several specific findings--interstitial fibrosis, toxic tubulopathy, peritubular capillary congestion, arteriolopathy--have been associated with CyA administration. It is now recognized that CyA renal toxicity mainly manifests under three different syndromes: (1) acute reversible decrease in glomerular filtration rate (GFR), (2) acute microvascular disease with the pattern of thrombotic microangiopathy, and (3) chronic irreversible renal damage. This review analyzes the available evidence that the clinical syndromes of CyA nephrotoxicity are related to changes induced by CyA on renal vessels. Experimental studies have failed to document that the activation of renin-angiotensin axis or sympathetic nervous system plays a relevant role in the development of CyA-associated renal vasoconstriction, which is the main causal factor of acute reversible decrease in GFR, whereas it is possible that changes in arachidonic acid metabolites with vasoactive properties contribute to this CyA-induced phenomenon. In this context, findings of increased urinary TxB2 and protective effect of TxA2 receptor blocking are of particular interest. Since the introduction of CyA in clinical practice, a syndrome of thrombotic microangiopathy resembling hemolytic uremic syndrome/thrombotic thrombocytopenic purpura has been recognized in humans and reproduced in experimental animals. This is a rare form of vascular toxicity attributed to CyA which may have a poor prognosis and possibly results from a direct toxic effect of CyA on vascular endothelium. The syndrome of chronic progressive deterioration of renal function associated with CyA was first recognized in humans. Until recently the possibility of reproducing this syndrome in animals in order to better understand its nature was not addressed. As in humans, when animals are given CyA for greater than 2 months they may develop chronic renal insufficiency with tubular arteriopathy and interstitial fibrosis. A peculiar form of tubulointerstitial damage has been recognized in association with CyA, and called striped interstitial fibrosis, that is probably due to tubular collapse induced by afferent vasoconstriction. This lesion may be improved by withdrawal of CyA, but renal function usually does not normalize.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporin A: action and side-effects

Cyclosporin A (CSA) is a new, potent immunosuppressive agent which is of proven value in organ transplantation. The use of CSA is associated with numerous side-effects, of which a dose-dependent nephrotoxicity is the most serious. CSA nephrotoxicity can be divided into two major groups: (i) functional toxicity without significant morphological lesions and (ii) morphological forms of toxicity with tubular and/or vascular-interstitial lesions. Vascular-interstitial toxicity is the most serious form because the renal lesions are irreversible.