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A correction to the article "MiR-1294 acts as a tumor suppressor in clear cell renal cell carcinoma through targeting HOXA6", by W. Pan, L.-J. Pang, H.-L. Cai, Y. Wu, W. Zhang, J.-C. Fang, published in Eur Rev Med Pharmacol Sci 2019.

OBJECTIVE: Renal cancer represents about 3% of all human cancers. Clear cell renal cell carcinoma (ccRCC) is the main type of renal cancer. MicroRNAs (miRNAs) have been reported to play crucial roles in the carcinogenesis of human cancers. This study was aimed to investigate the expression of miR-1294 and the mechanisms underlying miR-1294-mediated ccRCC progression. MATERIALS AND METHODS: The miR-1294 expression levels in ccRCC cell lines were analyzed by quantified real time-PCR (qRT-PCR). The effect of the miR-1294 expression on the overall survival of ccRCC patients was analyzed by the Kaplan-Meier Plotter. Cell proliferation, colony growth, and cell invasion were examined by cell counting kit-8 assay, colony formation assay, and transwell invasion assay, respectively. The luciferase activity reporter assay and Western blot assay were conducted to validate the connection between miR-1294 and homeobox A6 (HOXA6). RESULTS: MiR-1294 was downregulated in ccRCC cell lines and correlated with the poor overall survival of ccRCC patients. The overexpression of miR-1294 inhibits ccRCC cell proliferation, colony growth, and cell invasion. HOXA6 was validated as a target of miR-1294 and negatively regulated by miR-1294. The overexpression of HOXA6 attenuated the miR-1294-mediated effects on ccRCC cellular functions. CONCLUSIONS: Our results indicated that miR-1294 functions as a tumor suppressor in ccRCC. MiR-1294 suppressed cell proliferation, colony formation, and invasion in ccRCC partially via targeting HOXA6. [ABSTRACT FROM AUTHOR]

The gimbal angle of a magnetically suspended control moment gyro system deviates from nominal values due to disturbances. This causes control constraints during attitude manoeuvres and increases the risk of encountering singularities. Presented is a new method to eliminate this disturbance of the gimbal servo-system using adaptive inverse control and the effectiveness of this method is shown. This compensates for gimbal angle offset and increases the precision of attitude manoeuvres during nonlinear friction disturbed torque and coupling torque caused by the high-speed magnetic suspended rotor. [ABSTRACT FROM AUTHOR]

BACKGROUND Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of hospitaliza-tion for heart failure and cardiovascular death among patients with chronic heart failure and a left ventricular ejection fraction of 40% or less. Whether SGLT2 inhibitors are effective in patients with a higher left ventricular ejection fraction remains less certain. METHODS We randomly assigned 6263 patients with heart failure and a left ventricular ejection fraction of more than 40% to receive dapagliflozin (at a dose of 10 mg once daily) or matching placebo, in addition to usual therapy. The primary outcome was a composite of worsening heart failure (which was defined as either an unplanned hospitalization for heart failure or an urgent visit for heart failure) or cardiovas. cular death, as assessed in a time-to-event analysis. RESULTS Over a median of 2.3 years, the primary outcome occurred in 512 of 3131 patients (16.4%) in the dapagliflozin group and in 610 of 3132 patients (19.5%) in the placebo group (hazard ratio, 0.82; 95% confidence interval [CI], 0.73 to 0.92; P<0.001). Worsening heart failure occurred in 368 patients (11.8%) in the dapagliflozin group and in 455 patients (14.5%) in the placebo group (hazard ratio, 0.79; 95% CI, 0.69 to 0.91); cardiovascular death occurred in 231 patients (7.4%) and 261 patients (8.3%), respectively (hazard ratio, 0.88; 95% CI, 0.74 to 1.05). Total events and symptom burden were lower in the dapagliflozin group than in the placebo group. Results were similar among patients with a left ventricular ejection fraction of 60% or more and those with a left ventricular ejection fraction of less than 60%, and results were similar in prespecified subgroups, including patients with or without diabetes. The incidence of adverse events was similar in the two groups. CONCLUSIONS Dapagliflozin reduced the combined risk of worsening heart failure or cardiovascular death among patients with heart failure and a mildly reduced or preserved ejection fraction. (Funded by AstraZeneca; DELIVER ClinicalTrials.gov number, NCT03619213.) [ABSTRACT FROM AUTHOR]

We sought to explore the relation between Chlamydia pneumoniae, cytomegalovirus (CMV), and cardiac transplant-associated arteriosclerosis. Serologic evidence of past Chlamydia pneumoniae infection was investigated in 3 patient groups at the time of cardiac catheterization: cardiac transplant recipients (n=49), patients having coronary artery bypass grafting (CABG) (n=39), and a control group free of angiographic coronary artery disease (n=21). High Chlamydia pneumoniae immunoglobulin G titers (> or =1:160) were more frequently observed in cardiac transplant recipients (odds ratio[OR] 13.7; 95% confidence intervals [CI] 1.6 to 117.4, p <0.05) and CABG patients (OR 21.7; 95% CI 1.6 to 287.0, p <0.05) than in controls. However, high Chlamydia pneumoniae titers did not distinguish between cardiac transplant recipients with or without angiographic transplant-associated arteriosclerosis or CABG patients with or without bypass vein graft disease. Furthermore, there was no significant relation between elevated Chlamydia pneumoniae titers and the presence or progression of transplant-associated arteriosclerosis in the subgroup of patients who were also CMV positive. Yet, analysis of the same angiograms demonstrated an association between CMV infection and the recent progression of transplant-associated arteriosclerosis. Thus, patients with cardiac transplantation have evidence of past Chlamydia pneumoniae and CMV infection but Chlamydia pneumoniae does not appear to have an independent role or synergistic relation to CMV in the development of transplant-associated arteriosclerosis. [ABSTRACT FROM AUTHOR]

BACKGROUND The selective cardiac myosin activator omecamtiv mecarbil has been shown to improve cardiac function in patients with heart failure with a reduced ejection fraction. Its effect on cardiovascular outcomes is unknown. METHODS We randomly assigned 8256 patients (inpatients and outpatients) with symptomatic chronic heart failure and an ejection fraction of 35% or less to receive omecamtiv mecarbil (using pharmacokinetic-guided doses of 25 mg, 37.5 mg, or 50 mg twice daily) or placebo, in addition to standard heart-failure therapy. The primary outcome was a composite of a first heart-failure event (hospitalization or urgent visit for heart failure) or death from cardiovascular causes. RESULTS During a median of 21.8 months, a primary-outcome event occurred in 1523 of 4120 patients (37.0%) in the omecamtiv mecarbil group and in 1607 of 4112 patients (39.1%) in the placebo group (hazard ratio, 0.92; 95% confidence interval [CI], 0.86 to 0.99; P=0.03). A total of 808 patients (19.6%) and 798 patients (19.4%), respectively, died from cardiovascular causes (hazard ratio, 1.01; 95% CI, 0.92 to 1.11). There was no significant difference between groups in the change from baseline on the Kansas City Cardiomyopathy Questionnaire total symptom score. At week 24, the change from baseline for the median N-terminal pro-B-type natriuretic peptide level was 10% lower in the omecamtiv mecarbil group than in the placebo group; the median cardiac troponin I level was 4 ng per liter higher. The frequency of cardiac ischemic and ventricular arrhythmia events was similar in the two groups. CONCLUSIONS Among patients with heart failure and a reduced ejection, those who received omecamtiv mecarbil had a lower incidence of a composite of a heart-failure event or death from cardiovascular causes than those who received placebo. (Funded by Amgen and others; GALACTIC-HF ClinicalTrials.gov number, NCT02929329; EudraCT number, 2016-002299-28.). [ABSTRACT FROM AUTHOR]

Examines the use of the thrombolysis in myocardial infarction frame count for the quantitative assessment of transplant-associated arteriosclerosis (TAA). Reliance on surveillance coronary angiography of clinical practice for the assessment of TAA; Quantitative approach to assessing TAA; Absence of severe structural narrowings in epicardial arteries.

Examines the effect of endogenous vitamin C on nitric oxide bioavailability and coronary endothelial vasomotor function in cardiac transplant recipients. Relation between plasma vitamin C concentration and coronary vasomotor response (CVR) to acetylcholine and nitroglycerin; Relation of plasma F(sub 2)-isoprostanes and CVR to acetylcholine and nitroglycerine.

Recipient-to-donor atrioatrial conduction across a suture line has been rarely reported after orthotopic heart transplantation. The relation of such conduction to symptomatic arrhythmias and its prevalence are not known. Recipient-to-donor atrioatrial conduction was demonstrated in a 28-year-old woman with paroxysmal supraventricular tachycardia 7 years after orthotopic heart transplantation. Atrial tachycardia in the recipient atria conducted 2:1 to the donor atria and was eliminated by radiofrequency catheter ablation of a left-sided atrioatrial electrical connection. The electrocardiogram at rest and during exercise, recorded before ablation of the recipient-to-donor connection, showed frequent atrial premature complexes, with variable coupling to the preceding sinus beats, and a change in P-wave morphology during exercise, which reverted to normal during the recovery period. These findings were eliminated by ablation of the recipient-to-donor connection. To determine the prevalence of recipient-to-donor atrioatrial conduction late after transplantation, we evaluated the exercise electrocardiograms of 50 subjects > 5 years after heart transplantation for these features of recipient-to-donor conduction. At least 1 feature was present in 5 subjects, and both were present in 1 subject. Electrical conduction can occur across surgical suture lines in the atria. Recipient-to-donor atrioatrial conduction may occur in < or = 10% of patients late after heart transplantation. It is a potential cause of arrhythmias that can be effectively treated with radiofrequency catheter ablation. [ABSTRACT FROM AUTHOR]

Objective: To explore the effect and investigate the molecular mechanism of different concentrations of total tanshinones alone and in combination with tyrosine kinase inhibitors (TKIs) on the proliferation inhibition and apoptosis of human myeloid leukemia cell lines. Methods: K562 and Kasumi-1 cell lines were purchased from the Shanghai Cell Bank of the Chinese Academy of Sciences, and the TKIs-resistant strain K562/T315I cell line was constructed in Molecular Medicine Research Center, Beijing Lu Daopei Institute of Hematology. Logarithmic growth phase cells were taken and divided into intervention groups with total tanshinone of 0, 2.19, 4.38, 8.75, 17.50 and 35.00 μg/ml intervention groups, which were inoculated in 96-well plates at a density of 1×10 4 cells/well and exposed to the drug for 24 h, and a control group treated with dimethyl sulfoxide was also set up simultaneously. All experiments were repeated independently 3-5 times. The proliferative activity of the cells was assessed using the CCK-8 assay, the apoptotic rates were measured by flow cytometry, and the expression levels of apoptosis-regulating proteins Bcl-2 and Bax were analyzed by Western blotting. The cell lines treated and untreated with total tanshinone were subjected to transcriptome sequencing and gene set enrichment analysis to identify differentially expressed genes. Results: The half-inhibitory concentration (IC 50 ) values of 8.75 μg/ml total tanshinone at 24 h for K562, K562/T315I and Kasumi-1 cells were (4.11±0.02), (4.95±0.04) and (3.98±0.01) μg/ml, respectively. When combined with 0.25 μmol/L imatinib, 8.75 μg/ml total tanshinone could enhance the induction of apoptosis effects on K562 and K562/T315I cell lines. After being treated with 4.38, 8.75, and 17.50 μg/ml of total tanshinone for 24 h, compared with the control group, total tanshinone upregulated the expression level of Bax protein, downregulated the expression level of Bcl-2 protein, and decreased the Bcl-2/Bax ratio (all P <0.05). Total tanshinone inhibited the proliferation-related signaling pathway and DNA damage repair pathway of myeloid leukemia cell lines, and activated the signaling pathway that induces apoptosis in leukemia cells. Conclusion: Different concentrations of total tanshinoneinhibites proliferation and promote apoptosis in K562, Kasumi-1 and TKIs-resistant K562/T315I cell lines, and further enhance the anti-leukemic effect when combined with TKIs.

Objective: To classify and quantify IKZF1 mutant transcripts in B-cell acute lymphoblastic leukemia (B-ALL) by RNA sequencing (RNA-seq) and bioinformatics analysis. Methods: A cohort of 263 B-ALL cases was enrolled at Hebei Yanda Ludaopei Hospital from September 2018 to September 2020. An integrated bioinformatics pipeline was developed to adapt the classification and quantification of IKZF1 transcripts from RNA-seq and was applied to sequencing data of these cases. The IKZF1 mutant transcripts classified by RNA-seq analysis were compared with the qualitative reverse transcription PCR (RT-PCR). Results: IKZF1 mutant transcripts were identified in 53 B-ALL patients by RT-PCR and Sanger sequencing, among which IK6 and IK10 transcripts accounted for 67.9% (36/53) and 28.3% (15/53) respectively. Additionally, 2 patients were double positive for IK6 and IK10. RNA-seq analysis identified 51 patients with IKZF1 mutant transcripts. Compared with the RT-PCR result, the detection sensitivity and specificity of RNA-seq analysis reached 94.3% (50/53) and 99.5% (209/210), respectively. Among the 50 patients with IKZF1 mutant transcripts both in RNA-seq and RT-PCR analysis, the ratio of mutant transcripts to total IKZF1 transcripts in 6 patients was 0.14 (0.11, 0.35), which was significantly lower than that of the other 44 patients [0.88 (0.35, 0.97), Z=-3.945, P <0.001]. IKZF1 mutations mostly occurred in Ph + and Ph-like B-ALL, characterized by abnormal JAK-STAT pathway, and B-ALL with PAX5 translocation. Conclusions: Through the optimized bioinformatics analysis process, RNA-seq data can be used to classify and quantitatively analyze IKZF1 transcripts in B-ALL. Furthermore, the relative expression of mutant IKZF1 transcripts was found to cluster into two groups, and IKZF1 mutation was found often accompanied with PAX5 translocations.

Objective: To explore the application and discovery of genotyping, gene sequencing, and gene expression analysis in the determination of ABO blood group subtypes and antigen expression abnormalities in hematological malignancies patients. Methods: From June 2019 to May 2020, three clinical cases were found with forward and reverse ABO typing discrepancy or atypical serologic agglutination pattern in the laboratory and blood transfusion department of Hebei Yanda Ludaopei Hospital were selected. Sequence-specific primer PCR (PCR-SSP) and Sanger sequencing of ABO gene coding regions were performed to determine the ABO genotypes, and whole transcriptome sequencing was used to analyze ABO and FUT1 gene expression levels. Results: A 12-year-old female acute lymphoblastic leukemia patient was determined as O.01.02 and BA.04 sub-genotype, corresponding to the serological B(A) subtype, and her ABO gene expression was normal (354.80). A 41-year-old female acute myeloid leukemia patient was determined as A1.02 and B.01 genotype, corresponding to the serological A(1)B phenotype, and her ABO gene expression was significantly reduced (45.70). A 42-year-old male with myelodysplastic syndrome and myelofibrosis was determined as A1.02 and A2.05 sub-genotype, corresponding to the serological A(1) and A(2) phenotype, respectively, and his ABO expression was negative. FUT1 expression was in the normal range in all three cases. The clinical blood product infusion strategy was formulated according to the genotype and the corresponding immunological subtype, and no significant transfusion-related adverse reactions occurred. Conclusion: Blood group sub-genotypes or aberrant gene expression can lead to ambiguities in serological blood group determination in hematological malignancies patients. ABO genotyping and gene expression analysis can help in this scenario and escort blood product infusion safety.

Background: The utility of long-term endomyocardial biopsy surveillance in heart transplant recipients has been questioned. This study was undertaken to identify risk factors for late rejection and to examine the impact of different biopsy surveillance protocols on outcomes using the registry of the Cardiac Transplant Research Database., Methods: The study group consisted of all adult patients who underwent heart transplantation at the 33 centers participating in this investigation between January 1, 1993 and January 1, 2002, survived past the second post-transplant year, and were followed-up by a defined surveillance biopsy protocol., Results: During a follow-up that consisted of 24,137 patient-years, 1,626 late rejections occurred. Shorter time since transplant, history of rejection, younger age and African-American ethnicity of the recipient were strong risk factors for late rejection. The practice of surveillance biopsy varied among institutions. Continued surveillance increased the rate of diagnosis of late rejection (RR = 1.3, p = 0.002). There was no reduction in the incidence of hemodynamically compromising rejection and no increase in survival in patients with long-term vs intermediate-term surveillance. Short-term surveillance was associated with an increased incidence of hemodynamically compromising rejection, particularly among high-risk patients, and increased mortality in African-American patients., Conclusions: There are no apparent benefits from surveillance biopsy beyond 5 years post-transplant. Surveillance biopsy between 2 and 5 years post-transplant was found to reduce mortality in African-American recipients. Non-African-American recipients at high risk for late rejection will likely benefit from surveillance up to 5 years post-transplant.

Arterial elasticity is determined by structural characteristics of the artery wall and by vascular smooth muscle tone. The identity of endogenous vasoactive substances that regulate elasticity has not been defined in humans. We hypothesized that NO, a vasodilator released constitutively by the endothelium, augments arterial elasticity. Seven healthy young men were studied. A 20-MHz intravascular ultrasound catheter was introduced through an arterial sheath to measure brachial artery cross-sectional area, wall thickness, and intra-arterial pressure. After control was established, indices of elasticity (pressure-area relationship, instantaneous compliance, and stress-strain, pressure-incremental elastic modulus (E(inc)), and pressure-pulse wave velocity relationships) were examined over 0 to 100 mm Hg transmural pressure obtained by inflation of an external cuff. Thereafter, the basal production of endothelium-derived NO was inhibited by N(G)-monomethyl-L-arginine (L-NMMA) (4 and 8 mg/min). Finally, nitroglycerin (2.5 and 12.5 microgram/min), an exogenous donor of NO, was given to relax the vascular smooth muscle. Elasticity was measured under all of these conditions. L-NMMA (8 mg/min) decreased brachial artery area (P=0.016) and compliance (P<0.0001) and increased E(inc) (P<0.01) and pulse wave velocity (P<0.0001). Nitroglycerin (12.5 microgram/min) increased brachial artery area (P<0.001) and compliance (P<0.001) and decreased pulse wave velocity (P=0.02). NO, an endothelium-derived vasodilator, augments arterial elasticity in the human brachial artery. Loss of constitutively released NO associated with cardiovascular risk factors may adversely affect arterial elasticity in humans.

Background: Atherosclerotic coronary arteries are prone to constriction but the underlying causes are incompletely understood. We tested the hypothesis that endothelin-1 (ET-1), a potent vasoconstrictor, contributes to the heightened tone of atherosclerotic human coronary arteries., Methods and Results: In 8 patients with coronary artery disease (CAD) and 8 patients with angiographically smooth coronary arteries (normal), we infused BQ-123, an antagonist of the ET(A) receptor, into a major coronary artery (infused artery) at 40 nmol/min for 60 minutes. The infused artery in the CAD patients contained a >50% stenosis. Using quantitative angiography, we compared the dilation of the infused artery with another, noninfused coronary artery. To estimate the magnitude of the contribution of ET-1 to coronary tone, we compared the dilation to BQ-123 with that elicited by intracoronary nitroglycerin (200 microgram). BQ-123 induced significant dilation in the normal arteries (7.3% at 60 minutes, P<0.001 versus noninfused arteries) and a greater dilation in the CAD arteries (16.3% at 60 minutes, P<0.001 versus infused normal arteries). The dilation at stenoses was particularly pronounced (21.6% at 60 minutes, P<0.001 versus infused CAD arteries). Compared with the dilation from nitroglycerin, ET-1 contributed to 39% of the coronary tone in normal arteries, 74% of tone in CAD arteries, and 106% of tone at stenoses (P<0.01)., Conclusions: ET-1 accounts for nearly all the resting tone in atherosclerotic coronary arteries, especially at stenoses. Inhibitors of ET-1, by relieving constriction, may significantly lessen the hemodynamic significance of coronary stenoses and thereby reduce myocardial ischemia.

Gastro-oesophageal reflux disease (GERD) is the most common peptic acid disease in the western world and is the commonest indication for acid suppression therapy. Major advances have been made over the past 30 years in the understanding of lower oesophageal sphincter function and the mechanism of acid secretion. Developments in surgical and pharmacological therapy have paralleled these advances. Pharmacotherapy for GERD has evolved from antacids to H2-receptor antagonists (H2RAs) to prokinetics to proton pump inhibitors (PPIs). The H2RAs, while modestly effective in symptom relief and healing of GERD, are limited by pharmacological tolerance. The prokinetics (metoclopramide and cisapride) are limited by low efficacy, pharmacological tolerance and toxicity. The PPIs have emerged as the most effective therapy for symptom relief, healing and long-term maintenance. They have also proved to be remarkably safe and cost-effective in long-term therapy. This review evaluates the pharmacology, efficacy, tolerability, safety and cost-effectiveness of the four currently available PPIs, lansoprazole, omeprazole, pantoprazole and rabeprazole, in the treatment of GERD.

Background: In the presence of atherosclerosis, the coronary endothelial vasomotor response to acetylcholine is frequently abnormal but is variable between patients. We tested the hypothesis that the plasma concentration of alpha-tocopherol is associated with the preservation of nitric oxide-mediated endothelium-dependent vasomotion., Methods and Results: We studied 15 men and 6 women (mean age 61+/-10 years) at coronary angiography who were not taking vitamin supplements. Coronary endothelium-dependent and -independent vasomotion was assessed by intracoronary infusions of acetylcholine and nitroglycerin. The vasomotor responses were compared with the plasma concentration of alpha-tocopherol and the plasma alpha-tocopherol concentration relative to total lipid (total cholesterol plus triglycerides). The mean plasma alpha-tocopherol was 25.6+/-6.1 micromol/L, total cholesterol 193+/-27 mg/dL, triglycerides 115+/-66 mg/dL, and alpha-tocopherol to total lipid 4. 2+/-0.9 micromol. L(-1). (mmol/L)(-1). The mean vasomotor response to acetylcholine was -1% (range -33% to 28%) and to nitroglycerin 22% (range 0% to 54%). Plasma alpha-tocopherol was significantly correlated with the acetylcholine response (r=0.49, P<0.05) but not the nitroglycerin response (r=0.13, P>0.05). The acetylcholine response remained significant after adjustment for other potential sources of oxidant stress (total cholesterol, diabetes mellitus, smoking, angina class) (P<0.01). The relative concentration of alpha-tocopherol to total lipid was not related to endothelial function (r=0.24, P=0.3, n=20)., Conclusions: alpha-Tocopherol may preserve endothelial vasomotor function in patients with coronary atherosclerosis. This effect may be related primarily to the action of alpha-tocopherol in the vascular wall. Further studies that assess the impact of alpha-tocopherol supplementation as therapy of endothelial dysfunction are justified.

A cross-sectional study was conducted in an urban population 25 years of age and older to determine the prevalence of diabetes mellitus (DM), impaired glucose tolerance (IGT), and associated risk factors. A total of 13,940 subjects was surveyed (7,042 male, 6,898 female). The prevalence (DM 2.33%, IGT 1.30) was much higher than in a 1978 study. Age-standardised prevalence was not statistically different between males and females: respectively 2.54% and 2.14% for DM and 1.42% and 1.31% for IGT. Most diabetic patients were well-educated and performed mildly intensive labour. More patients showed a family history of diabetes during youth and risk factors associated with diabetes in old age, e.g. hypertension and an overweight condition. Microalbuminuria was found in 20.26% of newly diagnosed diabetic patients, i.e. a much higher proportion than in the normal population.

Background: Transplant-associated arteriosclerosis is the major limitation to long-term survival in the cardiac transplant recipient, and annual surveillance angiography is used in many centers to monitor its progression. Noninvasive methods would be preferable because angiography is invasive, costly, and insensitive; however, the reliability of such methods has been questioned., Methods: All publications relating to the assessment of the cardiac allograft by noninvasive testing were identified through MEDLINE and a review of references from the published literature on transplant-associated arteriosclerosis., Results: Resting and stress ECG, radionuclide scintigraphy, echocardiography, and positron emission tomography have all been used in cardiac transplant recipients with variable results. Most techniques are insensitive, but this limitation may be improved with pharmacologic stress imaging like dobutamine echocardiography. Although insensitive, some methods have good specificity (i.e., radionuclide scintigraphy). The noninvasive measurement of absolute coronary blood flow is promising as a specific and sensitive technique but is limited by availability and cost., Conclusions: In general, noninvasive techniques to assess transplant-associated coronary arteriosclerosis are limited by variable sensitivity and specificity. However, certain methods, such as dobutamine echocardiography and radionuclide scintigraphy, can provide important adjunctive physiologic information to angiography. Such techniques can therefore help to guide the care and treatment of the cardiac transplant recipient with allograft coronary arteriosclerosis.

Major advances have been made in understanding the expression and function of CD40 and its ligand CD154. It is now clear that CD40/CD154 interactions are critical in many aspects of the immune response, including T cell activation, T cell-dependent macrophage activation, T cell-B cell interactions and endothelial activation. Moreover, increasing evidence supports a central role for CD40/CD154 interactions in the immune processes of allograft rejection. Functional studies using blocking monoclonal antibodies have revealed beneficial effects of interupting CD40/CD154 co-stimulation in animal models of transplantation, particularly in association with interuption of the CD28/B7 pathway. A next step is to develop new therapeutic approaches to interrupting this pathway in humans, either through the development of receptor antagonists or through the understanding of intracellular signaling pathways utilized by these molecules.

Background: CD40 is expressed by a wide variety of cells in the immune system, including endothelial cells. It binds to CD40 ligand ([CD40L] CD154), which was originally reported to be restricted in its expression to early-activated T cells. We report here the expression of CD40 and CD40L in human cardiac allografts., Methods: A total of 123 consecutive biopsies from 11 human cardiac allograft recipients were analyzed by immunohistochemistry for the expression of CD40 and CD40L. The expression of CD40L was also examined in vitro in homogeneous cultures of umbilical vein endothelial cells by reverse transcriptase-polymerase chain reaction and by flow cytometry., Results: CD40 was expressed at low levels, and CD40L was minimal or absent in histologically normal biopsies in the absence of CD3+ T-cell infiltrates. In rejection, the expression of CD40 increased on vascular endothelial cells and on graft-infiltrating leukocytes throughout biopsy specimens. Induced expression of CD40 was strongly associated with the presence of CD3+ T-cell infiltrates, acute rejection, and ischemic injury (P<0.05). CD40L was expressed in biopsies with rejection and was prominent on a subset of infiltrating leukocytes as well as on microvascular endothelial cells. In contrast to CD40, staining of endothelial CD40L was focal in most biopsies. Overall, the expression of CD40L correlated with the presence of CD3+ T-cell infiltrates and rejection (P<0.05), but not ischemic injury (P=0.9). To confirm that the endothelium can synthesize CD40L, we also evaluated the expression of endothelial CD40L in vitro. Cultured endothelial cells were found to express little constitutive CD40L that markedly increased after 24 hr of treatment with supernatants from phytohemagglutinin-activated peripheral blood mononuclear cells or by the cytokines tumor necrosis factor-alpha, interleukin-1a, interleukin-4, or interferon-gamma., Conclusion: Both CD40 and CD40L are expressed in vivo on infiltrating leukocytes and on microvascular endothelium in human cardiac allograft rejection. We suggest that endothelial cell CD40 and CD40L play a role in human cell-mediated immune responses such as cardiac allograft rejection.