Cardiovascular outcomes after simultaneous pancreas kidney transplantation compared to kidney transplantation alone: a propensity score matching analysis

Background

Coronary heart disease due to arteriosclerosis is the leading cause of death in type 1 diabetic patients with end-stage renal disease (ESRD). The aim of this study was to evaluate the effect of simultaneous pancreas kidney transplantation (SPKT) compared to kidney transplantation alone (KTA) on survival, cardiovascular function and metabolic outcomes.

Methods

A cohort of 127 insulin-dependent diabetes mellitus (IDDM) patients with ESRD who underwent either SPKT (n = 100) or KTA (n = 27) between 1998 and 2019 at the University Hospital of Leipzig were retrospectively evaluated with regard to cardiovascular and metabolic function/outcomes as well as survival rates. An additional focus was placed on the echocardiographic assessment of systolic and diastolic cardiac function pretransplant and during follow-up. To avoid selection bias, a 2:1 propensity score matching analysis (PSM) was performed.

Results

After PSM, a total of 63 patients were identified; 42 patients underwent SPKT, and 21 patients received KTA. Compared with the KTA group, SPKT recipients received organs from younger donors (p < 0.05) and donor BMI was higher (p = 0.09). The risk factor-adjusted hazard ratio for mortality in SPKT recipients compared to KTA recipients was 0.63 (CI: 0.49–0.89; P < 0.05). The incidence of pretransplant cardiovascular events was higher in the KTA group (KTA: n = 10, 47% versus SPKT: n = 10, 23%; p = 0.06), but this difference was not significant. However, the occurrence of cardiovascular events in the SPKT group (n = 3, 7%) was significantly diminished after transplantation compared to that in the KTA recipients (n = 6, 28%; p = 0.02). The cardiovascular death rate was higher in KTA recipients (19%) than in SPK recipients with functioning grafts (3.3%) and comparable to that in patients with failed SPKT (16.7%) (p = 0.16).

In line with pretransplant values, SPKT recipients showed significant improvements in Hb1ac values (p = 0.001), blood pressure control (p =  < 0.005) and low-density lipoprotein/high-density lipoprotein (LDL/HDL) ratio (p =  < 0.005) 5 years after transplantation. With regard to echocardiographic assessment, SPKT recipients showed significant improvements in left ventricular systolic parameters during follow-up.

Conclusions

Normoglycaemia and improvement of lipid metabolism and blood pressure control achieved by successful SPKT are associated with beneficial effects on survival, cardiovascular outcomes and systolic left ventricular cardiac function. Future studies with larger samples are needed to make predictions regarding cardiovascular events and graft survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02522-8.

Protease-activated receptor 2 deficiency mediates cardiac fibrosis and diastolic dysfunction

AIMS

Heart failure with preserved ejection fraction (HFpEF) and pathological cardiac aging share a complex pathophysiology, including extracellular matrix remodelling (EMR). Protease-activated receptor 2 (PAR2) deficiency is associated with EMR. The roles of PAR1 and PAR2 have not been studied in HFpEF, age-dependent cardiac fibrosis, or diastolic dysfunction (DD).

METHODS AND RESULTS

Evaluation of endomyocardial biopsies from patients with HFpEF (n = 14) revealed that a reduced cardiac PAR2 expression was associated with aggravated DD and increased myocardial fibrosis (r = -0.7336, P = 0.0028). In line, 1-year-old PAR2-knockout (PAR2ko) mice suffered from DD with preserved systolic function, associated with an increased age-dependent α-smooth muscle actin expression, collagen deposition (1.7-fold increase, P = 0.0003), lysyl oxidase activity, collagen cross-linking (2.2-fold increase, P = 0.0008), endothelial activation, and inflammation. In the absence of PAR2, the receptor-regulating protein caveolin-1 was down-regulated, contributing to an augmented profibrotic PAR1 and transforming growth factor beta (TGF-β)-dependent signalling. This enhanced TGF-β/PAR1 signalling caused N-proteinase (ADAMTS3) and C-proteinase (BMP1)-related increased collagen I production from cardiac fibroblasts (CFs). PAR2 overexpression in PAR2ko CFs reversed these effects. The treatment with the PAR1 antagonist, vorapaxar, reduced cardiac fibrosis by 44% (P = 0.03) and reduced inflammation in a metabolic disease model (apolipoprotein E-ko mice). Patients with HFpEF with upstream PAR inhibition via FXa inhibitors (n = 40) also exhibited reduced circulating markers of fibrosis and DD compared with patients treated with vitamin K antagonists (n = 20).

CONCLUSIONS

Protease-activated receptor 2 is an important regulator of profibrotic PAR1 and TGF-β signalling in the heart. Modulation of the FXa/FIIa-PAR1/PAR2/TGF-β-axis might be a promising therapeutic approach to reduce HFpEF.

Equilibrated Charge Carrier Populations Govern Steady-State Nongeminate Recombination in Disordered Organic Solar Cells

We employed bias-assisted charge extraction techniques to investigate the transient and steady-state recombination of photogenerated charge carriers in complete devices of a disordered polymer-fullerene blend. Charge recombination is shown to be dispersive, with a significant slowdown of the recombination rate over time, consistent with the results from kinetic Monte Carlo simulations. Surprisingly, our experiments reveal little to no contributions from early time recombination of nonequilibrated charge carriers to the steady-state recombination properties. We conclude that energetic relaxation of photogenerated carriers outpaces any significant nongeminate recombination under application-relevant illumination conditions. With equilibrated charges dominating the steady-state recombination, quasi-equilibrium concepts appear suited for describing the open-circuit voltage of organic solar cells despite pronounced energetic disorder.

Charge Transport by Superexchange in Molecular Host-Guest Systems

Charge transport in disordered organic semiconductors is generally described as a result of incoherent hopping between localized states. In this work, we focus on multicomponent emissive host-guest layers as used in organic light-emitting diodes (OLEDs), and show using multiscale ab initio based modeling that charge transport can be significantly enhanced by the coherent process of molecular superexchange. Superexchange increases the rate of emitter-to-emitter hopping, in particular if the emitter molecules act as relatively deep trap states, and allows for percolation path formation in charge transport at low guest concentrations.

The effect of clopidogrel on platelet activity in patients with and without type-2 diabetes mellitus: a comparative study

Background

Although antiplatelet therapy involving clopidogrel is a standard treatment for preventing cardiovascular events after coronary stent implantation, patients can display differential responses. Here, we assessed the effectiveness of clopidogrel on platelet function inhibition in subjects with and without type-2 diabetes and stable coronary artery disease. In addition, we investigated the correlation between platelet function and routine clinical parameters.

Methods

A total of 64 patients with stable coronary heart disease were enrolled in the study. Among these, 32 had known type-2 diabetes, whereas the remaining 32 subjects were non-diabetics (control group). A loading dose of 300 mg clopidogrel was given to clopidogrel-naïve patients (13 patients in the diabetes group and 14 control patients). All patients were given a daily maintenance dose of 75 mg clopidogrel. In addition, all patients received 100 mg ASA per day. Agonist-induced platelet aggregation measurements were performed on hirudin-anticoagulated blood using an impedance aggregometer (Multiple Platelet Function Analyzer, Dynabyte, Munich, Germany). Blood samples were drawn from the antecubital vein 24 h after coronary angiography with percutaneous coronary intervention. The platelets were then stimulated with ADP alone or ADP and prostaglandin-E (ADP and ADP-PGE tests, respectively) in order to evaluate clopidogrel-mediated inhibition of platelet function. The effectiveness of ASA was measured by stimulation with arachidonic acid (ASPI test). In addition, maximal platelet aggregation was assessed via stimulation with thrombin receptor-activating peptide (TRAP test).

Results

Patients with diabetes exhibited significantly less inhibition of platelet function than patients without diabetes (ADP-PGE test p = 0.003; ASPI test p = 0.022). Administering a clopidogrel loading dose of 300 mg did not result in a lower level of ADP-PGE-induced platelet reactivity in comparison to the use of a 75 mg maintenance dose. Moreover, we observed that ADP-PGE-induced platelet inhibition was positively correlated with fasting blood glucose and HbA1c (p < 0.01).

Conclusions

Patients with type-2 diabetes exhibited increased platelet reactivity compared to patients without diabetes despite combined treatment with clopidogrel and ASA. Using a loading dose of clopidogrel rather than small daily doses was not sufficient for adequately overcoming increased platelet reactivity in patients with type-2 diabetes, highlighting the need for more effective anti-platelet drugs for such patients.

High leptin and resistin expression in chronic heart failure: adverse outcome in patients with dilated and inflammatory cardiomyopathy

AIM

The expression of leptin and resistin is known to be positively correlated with the incidence of chronic heart failure (CHF). Both adipokines have been implicated in immunomodulation and cardiac remodelling. Therefore, we performed for the first time a clinical study to elucidate the effects of leptin and resistin on progression of CHF in patients with non-ischaemic dilated (DCM) and inflammatory (DCMi) cardiomyopathy.

METHODS AND RESULTS

For the clinical study 120 patients were divided into a control (n = 16), DCM (n = 52), and DCMi (n = 52) group to determine the effect of leptin and resistin on CHF progression. Nuclear factor-κB (NF-κB) activation, reactive oxygen species generation, and tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) expression following adipokine exposition were determined in vitro in cardiomyocytes. Leptin and resistin systemic plasma levels and not cardiac expression were significantly elevated in patients with DCM (leptin, 13.12 ± 17.2 ng/mL, P < 0.05; resistin, 6.87 ± 2.25 ng/mL, P < 0.05) and DCMi (leptin, 13.63 ± 16 ng/mL, P < 0.05; resistin, 7.27 ± 2.2 ng/mL, P < 0.05) compared with the control group (leptin, 7.34 ± 5.7 ng/mL; resistin, 4.4 ± 1.18 ng/mL). A multivariate linear regression model revealed low leptin and resistin plasma levels as contributors for favourable cardiac functional parameters at 6-month follow-up independent of inflammatory conditions. Cell culture experiments in vitro showed leptin and resistin to be potent regulators of TNF-α and IL-6 expression in cardiomyocytes, leading to significantly increased redox stress in cardiac cells.

CONCLUSIONS

High leptin and resistin expression in patients with DCM and DCMi is associated with CHF progression, i.e. severe cardiac dysfunction, independent of immune responses.

Bivalirudin inhibits periprocedural platelet function and tissue factor expression of human smooth muscle cells

AIM

A major concern of stent implantation after percutaneous coronary intervention (PCI) is acute stent thrombosis. Effective inhibition of periprocedural platelet function in patients with coronary artery disease (CAD) leads to an improved outcome. In this study, we examined the periprocedural platelet reactivity after administrating bivalirudin during PCI compared to unfractionated heparin (UFH) administration. Further, the effect of bivalirudin on induced tissue factor (TF) expression in smooth muscle cells (SMC) was determined.

METHODS

Patients with CAD (n = 58) and double antithrombotic medication were treated intraprocedural with UFH (n = 30) or bivalirudin (n = 28). Platelet activation markers were flow cytometrically measured before and after stenting. The expression of TF in SMC was determined by real-time PCR and Western blotting. The thrombogenicity of platelet-derived microparticles and SMC was assessed via a TF activity assay.

RESULTS

Bivalirudin significantly diminished the agonist-induced platelet reactivity post-PCI. Compared to UFH treatment, the adenosine diphosphate (ADP) and thrombin receptor-activating peptide (TRAP)-induced thrombospondin expression post-PCI was reduced when bivalirudin was administrated during intervention. In contrast to UFH, bivalirudin reduced the P-selectin expression of unstimulated and ADP-induced platelets post-PCI. Moreover, bivalirudin inhibited the thrombin-, but not FVIIa- or FVIIa/FX-induced TF expression and pro-coagulant TF activity of SMC. Moreover, bivalirudin reduced the TF activity of platelet-derived microparticles postinduction with TRAP or ADP.

CONCLUSIONS

Bivalirudin is better than UFH in reducing periprocedural platelet activation. Moreover, thrombin-induced TF expression is inhibited by bivalirudin. Thus, bivalirudin seems to be a better anticoagulant during PCI than UFH.

Leptin and resistin induce increased procoagulability in diabetes mellitus

BACKGROUND

Patients with diabetes mellitus (DM) suffer from an increased risk of cardiovascular events caused by thrombotic conditions. Adipose tissue might play a crucial role in this pathogenesis by synthesis of procoagulant mediators. This study was performed to elucidate the role of the adipocytokines leptin and resistin in the development of hypercoagulability and hypofibrinolysis under diabetic conditions.

METHODS

Sixty two patients with or without DM were included in our study to measure leptin, resistin and tissue factor (TF) plasma concentrations. Moreover, flow chamber experiments were performed to assess factor Xa and plasmin activity on the surface of HUVECs. Western blot and real-time PCR were performed to determine mRNA and protein expression of main factors of the coagulation and fibrinolytic system.

RESULTS

Patients with diabetes showed increased levels of leptin and resistin (leptin: 25.69±13.9 vs. 15.98±17.5 ng/mL, p<0.05; resistin: 2.61±0.6 vs. 1.19±0.7 ng/mL, p<0.05), which were positively correlated with TF. In vitro, leptin and resistin induced increased factor Xa activity (leptin: 4.29±0.57-fold, p<0.05; resistin 4.19±0.7-fold, p<0.05 vs. control) on HUVECs as also reflected by elevated TF mRNA and protein expression. Moreover, stimulatory (plasminogen activator inhibitor 1) and inhibitory (tissue plasminogen activator) mediators of the fibrinolytic cascade were induced by leptin and resistin, leading to a balanced plasmin activity regulation.

CONCLUSIONS

Leptin and resistin lead to a procoagulant state in HUVECs by inducing TF expression. This mechanism might be one explanation for the prothrombotic state observed under diabetic conditions.

Adiponectin expression in patients with inflammatory cardiomyopathy indicates favourable outcome and inflammation control

AIMS

Circulating adiponectin (APN) is an immunomodulatory, pro-angiogenic, and anti-apoptotic adipocytokine protecting against acute viral heart disease and preventing pathological remodelling after cardiac injury. The purpose of this study was to describe the regulation and effects of APN in patients with inflammatory cardiomyopathy (DCMi).

METHODS AND RESULTS

Adiponectin expression and outcome were assessed in 173 patients with DCMi, 30 patients with non-inflammatory DCM, and 30 controls. Mechanistic background of these findings was addressed in murine experimental autoimmune myocarditis (EAM), a model of human DCMi, and further elucidated in vitro. Adiponectin plasma concentrations were significantly higher in DCMi compared with DCM or controls, i.e. 6.8 ± 3.9 µg/mL vs. 5.4 ± 3.6 vs. 4.76 ± 2.5 µg/mL (P< 0.05, respectively) and correlated significantly with cardiac mononuclear infiltrates (CD3+: r(2)= 0.025, P= 0.038; CD45R0+: r(2)= 0.058, P= 0.018). At follow-up, DCMi patients with high APN levels showed significantly increased left ventricular ejection fraction improvement, decreased left ventricular end-diastolic diameter, and reduced cardiac inflammatory infiltrates compared with patients with low APN levels. A multivariate linear regression analysis implicated APN as an independent prognostic factor for inhibition of cardiac inflammation. In accordance with these findings in human DCMi, EAM mice exhibited elevated plasma APN. Adiponectin gene transfer led to significant downregulation of key inflammatory mediators promoting disease. Mechanistically, APN acted as a negative regulator of T cells by reducing antigen specific expansion (P< 0.01) and suppressed TNFα-mediated NFκB activation (P< 0.01) as well as release of reactive oxygen species in cardiomyocytes.

CONCLUSION

Our results implicate that APN acts as endogenously upregulated anti-inflammatory cytokine confining cardiac inflammation and progression in DCMi.

Increased plasma retinol binding protein 4 levels in patients with inflammatory cardiomyopathy

AIMS

Chronic heart failure (CHF) is associated with a higher risk for diabetes mellitus. Retinol binding protein 4 (RBP 4) is an adipose tissue-derived protein with pro-diabetogenic effects. A complete understanding of the association of CHF and insulin resistance remains elusive. The purpose of this study was to examine the relationship between CHF and diabetes mellitus.

METHODS AND RESULTS

Plasma levels of RBP 4, insulin, and interleukins (IL) 2, 8, and 10, were assessed in patients with dilated cardiomyopathy (DCM, n = 53), dilated inflammatory cardiomyopathy (DCMi, n = 54), and controls (n = 20). In addition, a possible mechanism of RBP 4 regulation was examined in adipocytes in vitro. Plasma levels of RBP 4 and insulin were measured by a specific ELISA. Interleukin concentrations were obtained by multiplex ELISA. Cell culture with 3T3-L1 adipocytes was performed to measure RBP 4 mRNA expression after stimulation with IL-8. RBP 4 levels were significantly increased in patients with DCMi (52.95 +/- 20.42 microg/mL) compared with DCM (35.54 +/- 23.08 microg/mL) and the control group (27.3 +/- 18.51 microg/mL). RBP 4 was positively correlated with IL-8 (r=0.416, P < 0.05) in human plasma in patients with DCMi. Moreover, increased insulin resistance was observed in patients with DCMi compared with the control and DCM groups. In vitro, IL-8 induced a significant upregulation of RBP 4 mRNA expression in adipocytes.

CONCLUSION

Elevated RBP 4 plasma concentrations, induced by IL-8, might be one mechanism leading to a higher incidence of diabetes in patients with DCMi.

High molecular weight adiponectin correlates positively with myeloperoxidase in patients with type 2 diabetes mellitus

Adiponectin (APN) is present in human plasma as a low molecular weight (LMW), a middle molecular weight (MMW) and a high molecular weight form (HMW). As a support to determine properties such as anti-atherogenic or atherogenic effects, recent clinical studies suppose to determine the ratio of each APN multimer to total APN but not the absolute plasma concentration of APN. In the present study, the correlation of APN and its multimers with myeloperoxidase (MPO), an enzyme with pro-inflammatory properties, was examined in patients with type 2 diabetes mellitus. MPO and APN serum levels were assessed in 49 patients with type 2 diabetes mellitus at the beginning and at the end of an anti-diabetic treatment. After treatment a significant increase in the ratio of HMW to total APN (from 0.43+/-0.16 to 0.59+/-0.14, p<0.05) was found. Before treatment, HMW-APN was correlated positively with MPO (r=0.314, p<0.05). Moreover, a positive correlation was observed between the increased HMW ratio and MPO during treatment (r=0.304, p<0.05). HMW-APN correlates positively with MPO in patients with type 2 diabetes. Therefore, HMW-APN may exert possible pro-inflammatory effects in type 2 diabetes.

Diadenosine polyphosphates Ap3A and Ap4A, but not Ap5A or Ap6A, induce proliferation of vascular smooth muscle cells

Depending on the number of phosphate groups, diadenosine polyphosphates (ApnA, Ap3A, Ap4A, Ap5A and Ap6A) differ in properties such as proliferation, apoptosis, vasoconstriction and vasodilatation of vascular smooth muscle cells (VSMCs). Possible signaling pathways leading to effects such as proliferation are still unknown. This study examined the proliferative effects of diadenosine polyphosphates on VSMCs and their intracellular pathways. Proliferation of VSMCs was measured by the cell count and [(3)H] thymidine incorporation. Phosphorylation of the MAP kinases ERK1/2 was determined by Western blotting. Single-cell [Ca(2+)](i) measurements were done to determine the influence of [Ca(2+)](i) on intracellular signaling. Stress fiber formation was assessed by fluorescence microscopy to detect an influence of G alpha(12). Ap3A and Ap4A, but not Ap5A or Ap6A, were shown to increase proliferation of VSMCs by activating P2Y receptors, which leads to stimulation of the Ras-Raf-MEK-ERK1/2 cascade. Ap3A- and Ap4A-induced activation of the MAP kinases ERK1/2 was dependent on a signaling pathway that included the EGF receptor, PKC, PLCbeta and the increase of [Ca(2+)](i). In conclusion, Ap3A and Ap4A, but not Ap5A or Ap6A, induce proliferation of VSMCs by a signaling pathway that begins with activation of P2Y receptors and leads to stimulation of the MAP kinases ERK1/2.

Globular adiponectin but not full-length adiponectin induces increased procoagulability in human endothelial cells

Adiponectin (APN), a recently discovered adipocytokine, is present in human serum in a full length (fAPN) and a globular form (gAPN). gAPN is a proteolytic cleavage product of fAPN and seems to show independent biological activities compared to the properties of fAPN. The influence of gAPN and fAPN on procoagulability of cells is still unknown. This study examined the effect of gAPN and fAPN on the expression of tissue factor (TF), the initiator of the extrinsic coagulation system, in human umbilical vein endothelial cells (HUVECs). TF activity was measured by a chromogenic assay, TF mRNA by real-time PCR and TF protein by western blot. We found TF activity to be increased after activation by gAPN (3 microg/mL) compared to a non-stimulated control (169.0+/-19.23 U versus 501.9+/-38.95 U, p<0.001). Furthermore, TF mRNA and TF protein was increased dose-dependently after gAPN stimulation. The gAPN-induced rise of TF activity and TF mRNA was significantly reduced by inhibition of the MAP kinases ERK1/2, p38 and JNK. Contrary to gAPN, stimulation with fAPN did not lead to these procoagulant effects. In conclusion, gAPN increased TF transcription, expression and activity in HUVECs. Therefore, our data support the theory that gAPN but not fAPN supports the cellular procoagulability via TF upregulation.