Longitudinal monitoring of BKPyV miRNA levels in kidney transplant recipients with BKPyV-related pathology reflects viral DNA levels and remain high in viremia patients after clearance of viral DNA

INTRODUCTION

It is unclear whether polyomavirus BK (BKPyV) microribonucleic acid (miRNA) measurement has additional diagnostic and predictive value in kidney transplant recipients (KTR) as compared to current methods of monitoring BKPyV DNA loads.

PATIENTS AND METHODS

A retrospective, longitudinal study was performed in 30 KTR with BKPyV viruria (n = 10), BKPyV viremia (n = 10), or BKPyV-associated neuropathy (BKPyVAN) (n = 10). Bkv-miR-B1-3p and 5p and BKPyV DNA load were measured in urine and plasma and compared using receiver operating characteristic (ROC) curves.

RESULTS

Levels of Bkv-miR-B1-3p and 5p and BKPyV DNA correlated strongly. Overall, mostly analog courses of urinary and plasma miRNA and DNA loads were observed. Areas under the ROC curves were not significantly different between miRNAs and DNA. Only, in contrast to BKPyV DNA load, BKPyV miRNA levels increased from 6 to 12 months in the viremia group, while in the BKPyVAN group, a decline was seen in both DNA and miRNA.

CONCLUSIONS

In this study, we could not demonstrate an additional value of BKPyV miRNA detection compared to BKPyV DNA monitoring in the early phase after kidney transplantation. We did observe significant differences between the viremia and the BKPyVAN groups during follow-up. This study was performed with a small number of patients and therefore results should be verified in a larger patient cohort. Furthermore, future studies with larger patient groups are necessary to elucidate final clinical value of these data.

Regulatory T cells engineered with TCR signaling-responsive IL-2 nanogels suppress alloimmunity in sites of antigen encounter

Adoptive cell transfer of ex vivo expanded regulatory T cells (T_regs) has shown immense potential in animal models of auto- and alloimmunity. However, the effective translation of such T_reg therapies to the clinic has been slow. Because T_reg homeostasis is known to require continuous T cell receptor (TCR) ligation and exogenous interleukin-2 (IL-2), some investigators have explored the use of low-dose IL-2 injections to increase endogenous T_reg responses. Systemic IL-2 immunotherapy, however, can also lead to the activation of cytotoxic T lymphocytes and natural killer cells, causing adverse therapeutic outcomes. Here, we describe a drug delivery platform, which can be engineered to autostimulate T_regs with IL-2 in response to TCR-dependent activation, and thus activate these cells in sites of antigen encounter. To this end, protein nanogels (NGs) were synthesized with cleavable bis(N-hydroxysuccinimide) cross-linkers and IL-2/Fc fusion (IL-2) proteins to form particles that release IL-2 under reducing conditions, as found at the surface of T cells receiving stimulation through the TCR. T_regs surface-conjugated with IL-2 NGs were found to have preferential, allograft-protective effects relative to unmodified T_regs or T_regs stimulated with systemic IL-2. We demonstrate that murine and human NG-modified T_regs carrying an IL-2 cargo perform better than conventional T_regs in suppressing alloimmunity in murine and humanized mouse allotransplantation models. In all, the technology presented in this study has the potential to improve T_reg transfer therapy by enabling the regulated spatiotemporal provision of IL-2 to antigen-primed T_regs.

Intradialytic Complement Activation Precedes the Development of Cardiovascular Events in Hemodialysis Patients

Background: Hemodialysis (HD) is a life-saving treatment for patients with end stage renal disease. However, HD patients have markedly increased rates of cardiovascular morbidity and mortality. Previously, a link between the complement system and cardiovascular events (CV-events) has been reported. In HD, systemic complement activation occurs due to blood-to-membrane interaction. We hypothesize that HD-induced complement activation together with inflammation and thrombosis are involved in the development of CV-events in these patients. Methods: HD patients were followed for the occurrence of CV-events during a maximum follow-up of 45 months. Plasma samples were collected from 55 patients at different time points during one HD session prior to follow-up. Plasma levels of mannose-binding lectin, properdin and C3d/C3 ratios were assessed by ELISA. In addition, levels of von Willebrand factor, TNF-α and IL-6/IL-10 ratios were determined. An ex-vivo model of HD was used to assess the effect of complement inhibition. Results: During median follow-up of 32 months, 17 participants developed CV-events. In the CV-event group, the C3d/C3-ratio sharply increased 30 min after the start of the HD session, while in the event-free group the ratio did not increase. In accordance, HD patients that developed a CV-event also had a sustained higher IL-6/IL-10-ratio during the first 60 min of the HD session, followed by a greater rise in TNF-α levels and von Willebrand factor at the end of the session. In the ex-vivo HD model, we found that complement activation contributed to the induction of TNF-α levels, IL-6/IL-10-ratio and levels of von Willebrand factor. Conclusions: In conclusion, these findings suggest that early intradialytic complement activation predominantly occurred in HD patients who develop a CV-event during follow-up. In addition, in these patients complement activation was accompanied by a pro-inflammatory and pro-thrombotic response. Experimental complement inhibition revealed that this reaction is secondary to complement activation. Therefore, our data suggests that HD-induced complement, inflammation and coagulation are involved in the increased CV risk of HD patients.

The Complement System in Dialysis: A Forgotten Story?

Significant advances have lead to a greater understanding of the role of the complement system within nephrology. The success of the first clinically approved complement inhibitor has created renewed appreciation of complement-targeting therapeutics. Several clinical trials are currently underway to evaluate the therapeutic potential of complement inhibition in renal diseases and kidney transplantation. Although, complement has been known to be activated during dialysis for over four decades, this area of research has been neglected in recent years. Despite significant progress in biocompatibility of hemodialysis (HD) membranes and peritoneal dialysis (PD) fluids, complement activation remains an undesired effect and relevant issue. Short-term effects of complement activation include promoting inflammation and coagulation. In addition, long-term complications of dialysis, such as infection, fibrosis and cardiovascular events, are linked to the complement system. These results suggest that interventions targeting the complement system in dialysis could improve biocompatibility, dialysis efficacy, and long-term outcome. Combined with the clinical availability to safely target complement in patients, the question is not if we should inhibit complement in dialysis, but when and how. The purpose of this review is to summarize previous findings and provide a comprehensive overview of the role of the complement system in both HD and PD.

A delicate balance between rejection and BK polyomavirus associated nephropathy; A retrospective cohort study in renal transplant recipients

BACKGROUND

The immunosuppressive agents mycophenolate acid (MPA) and tacrolimus (Tac) are associated with a higher incidence of BK polyomavirus nephropathy (BKPyVAN). In this observational retrospective cohort study, the frequency of BK polyomavirus (BKPyV) complications over a 24-month period was studied.

METHODS

358 renal transplant recipients (RTR) treated with MPA, with either cyclosporine A (CsA) (CsAM group) or Tac (TacM group) and mostly prednisolone, were included.

RESULTS

Incidence of BKPyV-viremia was not significantly different between the CsAM (n = 42/191) (22.0%) and the TacM (n = 36/167) (21.6%) group. Biopsy proven BKPyVAN occurred more often in the TacM group (6.6%) versus the CsAM group (2.1%) (p = 0.03). Longitudinal data analysis showed a significant earlier decline of viral load in plasma in the CsAM group compared to the TacM group (p = 0.005). The incidence of biopsy proven acute rejection (BPAR) was significantly higher in the CsAM (19.9%) compared to the TacM (10.8%) (p = 0.02) group. Graft loss, estimated glomerular filtration rate and mortality rate did not differ in both treatment groups.

CONCLUSION

In conclusion, this study shows that immunosuppressive treatment with Tac and MPA compared to CsA and MPA is associated with a lower incidence of BPAR, but at the cost of an increased risk of developing BKPyVAN in the first two years post-transplant.

Human Cytomegalovirus-Encoded Receptor US28 Is Expressed in Renal Allografts and Facilitates Viral Spreading In Vitro

BACKGROUND

Renal transplantation is the preferred treatment for patients with end-stage renal disease. Human cytomegalovirus (HCMV) activation is associated with decreased renal graft function and survival. Human cytomegalovirus encodes several immune modulatory proteins, including the G protein-coupled receptor US28, which scavenges human chemokines and modulates intracellular signaling.

METHODS

Our aim was to identify the expression and localization of US28 in renal allograft biopsies by immunohistochemistry and determine its role in viral spreading in vitro.

RESULTS

Immunohistochemistry revealed US28 in 31 of 34 renal transplant biopsies from HCMV-seropositive donors. Expression was independent of HCMV viremia or IgG serostatus. US28 was predominantly expressed in the cytoplasm of vascular smooth muscle cells (VSMCs) and tubular epithelial cells, with a median positivity of 20% and 40%, respectively. Also, US28-positive cells were present within arterial neointima. In contrast to US28, HCMV-encoded immediate early antigen was detected in less than 5% of VSMCs, tubular epithelial cells, interstitial endothelium, interstitial inflammatory infiltrates, and glomerular cells.Primary VSMCs were infected with green fluorescent protein-tagged wild type or US28-deficient HCMV. The viral spreading of US28-deficient HCMV, via culture medium or cell-to-cell transmission, was significantly impeded as shown by green fluorescent protein (ie, infected) cell quantification and quantitative real-time polymerase chain reaction. Additionally, the number and size of foci was smaller.

CONCLUSIONS

In summary, HCMV-encoded US28 was detected in renal allografts from HCMV-positive donors independent of viremia and serostatus. Also, US28 facilitates HCMV spreading in VSMCs in vitro. Because the vasculature is affected in chronic renal transplant dysfunction, US28 may provide a potential target for therapeutic intervention.

Critical role for complement receptor C5aR2 in the pathogenesis of renal ischemia-reperfusion injury

The complement system, and specifically C5a, is involved in renal ischemia-reperfusion (IR) injury. The 2 receptors for complement anaphylatoxin C5a (C5aR1 and C5aR2) are expressed on leukocytes as well as on renal epithelium. Extensive evidence shows that C5aR1 inhibition protects kidneys from IR injury; however, the role of C5aR2 in IR injury is less clear as initial studies proposed the hypothesis that C5aR2 functions as a decoy receptor. By Using wild-type, C5aR1^-/-, and C5aR2^-/- mice in a model of renal IR injury, we found that a deficiency of either of these receptors protected mice from renal IR injury. Surprisingly, C5aR2^-/- mice were most protected and had lower creatinine levels and reduced acute tubular necrosis. Next, an in vivo migration study demonstrated that leukocyte chemotaxis was unaffected in C5aR2^-/- mice, whereas neutrophil activation was reduced by C5aR2 deficiency. To further investigate the contribution of renal cell-expressed C5aR2 vs leukocyte-expressed C5aR2 to renal IR injury, bone marrow chimeras were created. Our data show that both renal cell-expressed C5aR2 and leukocyte-expressed C5aR2 mediate IR-induced renal dysfunction. These studies reveal the importance of C5aR2 in renal IR injury. They further show that C5aR2 is a functional receptor, rather than a decoy receptor, and may provide a new target for intervention.-Poppelaars, F., van Werkhoven, M. B., Kotimaa, J., Veldhuis, Z. J., Ausema, A., Broeren, S. G. M., Damman, J., Hempel, J. C., Leuvenink, H. G. D., Daha, M. R., van Son, W. J., van Kooten, C., van Os, R. P., Hillebrands, J.-L., Seelen, M. A. Critical role for complement receptor C5aR2 in the pathogenesis of renal ischemia-reperfusion injury.

Strong predictive value of mannose-binding lectin levels for cardiovascular risk of hemodialysis patients

Background

Hemodialysis patients have higher rates of cardiovascular morbidity and mortality compared to the general population. Mannose-binding lectin (MBL) plays an important role in the development of cardiovascular disease. In addition, hemodialysis alters MBL concentration and functional activity. The present study determines the predictive value of MBL levels for future cardiac events (C-event), cardiovascular events (CV-event) and all-cause mortality in HD patients.

Methods

We conducted a prospective study of 107 patients on maintenance hemodialysis. Plasma MBL, properdin, C3d and sC5b-9 was measured before and after one dialysis session. The association with future C-events, CV-events, and all-cause mortality was evaluated using Cox regression models.

Results

During median follow-up of 27 months, 36 participants developed 21 C-events and 36 CV-events, whereas 37 patients died. The incidence of C-events and CV-events was significantly higher in patients with low MBL levels (<319 ng/mL, lower quartile). In fully adjusted models, low MBL level was independently associated with increased CV-events (hazard ratio 3.98; 95 % CI 1.88–8.24; P < 0.001) and C-events (hazard ratio 3.96; 95 % CI 1.49–10.54; P = 0.006). No association was found between low MBL levels and all-cause mortality. Furthermore, MBL substantially improved risk prediction for CV-events beyond currently used clinical markers.

Conclusions

Low MBL levels are associated with a higher risk for future C-events and CV-events. Therefore, MBL levels may help to identify hemodialysis patients who are at risk to develop cardiovascular disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0995-5) contains supplementary material, which is available to authorized users.

Precision-cut human kidney slices as a model to elucidate the process of renal fibrosis

Chronic kidney disease is a major health concern, and experimental models bridging the gap between animal studies and clinical research are currently lacking. Here, we evaluated precision-cut kidney slices (PCKSs) as a potential model for renal disease. PCKSs were prepared from human cortical tissue obtained from tumor nephrectomies and cultured up to 96 hours. Morphology, cell viability, and metabolic functionality (ie, uridine 5'-diphospho-glucuronosyltransferase and transporter activity) were determined to assess the integrity of PCKSs. Furthermore, inflammatory and fibrosis-related gene expressions were characterized. Finally, to validate the model, renal fibrogenesis was induced using transforming growth factor β1 (TGF-β1). Preparation of PCKSs induced an inflammatory tissue response, whereas long-term incubation (96 hours) induced fibrogenesis as shown by an increased expression of collagen type 1A1 (COL1A1) and fibronectin 1 (FN1). Importantly, PCKSs remained functional for more than 48 hours as evidenced by active glucuronidation and phenolsulfonphthalein uptake. In addition, cellular diversity appeared to be maintained, yet we observed a clear loss of nephrin messenger RNA levels suggesting that our model might not be suitable to study the role of podocytes in renal pathology. Moreover, TGF-β1 exposure augmented fibrosis, as illustrated by an increased expression of multiple fibrosis markers including COL1A1, FN1, and α-smooth muscle actin. In conclusion, PCKSs maintain their renal phenotype during culture and appear to be a promising model to investigate renal diseases, for example, renal fibrosis. Moreover, the human origin of PCKSs makes this model very suitable for translational research.

The clinical course of hepatitis E virus infection in patients of a tertiary Dutch hospital over a 5-year period

BACKGROUND

Hepatitis E virus (HEV) has long been known as a major cause of acute hepatitis in developing countries with occasional travel-related cases in developed countries, most of them belonging to genotype 1. Currently, genotype 3 HEV is recognized as an emerging public health issue in developed countries and can cause a chronic hepatitis in immunocompromised patients.

OBJECTIVES

The aim of this study was to get an overview of the clinical course of HEV infection, from July 2007 to December 2012, and further characterize HEV in patients of the University Medical Center Groningen (UMCG) over a 5-year time period.

METHODS

Since the second half of 2007, patients in the UMCG with unexplained hepatitis were screened for HEV and clinical data were collected. HEV was characterized by sequencing of the ORF1 and ORF2 regions.

RESULTS

In total, 34 patients of the 1129 tested patients showed HEV viremia. The majority of the infected patients were immunocompromised; 18 were solid organ transplant (SOT) patients and 9 were patients immunocompromised for other reasons. Seven patients diagnosed with HEV were immunocompetent. Viral genotyping revealed genotype 3 isolates, mostly genotype 3c.

CONCLUSION

Non-travel related HEV hepatitis is an important diagnosis. In immunocompromised patients HEV infection often has major clinical impact, necessitating medical intervention including antiviral treatment. In immunocompetent patients, the detection could expand our understanding about the route of transmission and the relation with the zoonotic origin. Therefore, besides an increasing awareness for HEV among clinicians and medical microbiologists, diagnostics should be routinely incorporated into standard patients care.

Latent cytomegalovirus infection is an independent risk factor for late graft failure in renal transplant recipients

Background

Cytomegalovirus (CMV) is a risk factor for rejection and mortality soon after renal transplantation. Little is known about its consequences longer after transplantation. We prospectively investigated whether latent CMV infection is a risk factor for graft failure and mortality long after transplantation.

Material/Methods

Our study included 606 renal transplant recipients (RTR) with a functioning graft for >1 year. CMV serology was determined using ELISA. RTRs were divided into CMV-seronegative and latent CMV (seropositive + seroconverted).

Results

We measured CMV IgG at 6.0 [2.6–11.4] years post-transplant. During follow-up (7.0 [6.2–7.5] years), 54 (9%) RTRs experienced graft failure and 137 (23%) RTRs died. Risk for graft failure and mortality was significantly higher in RTRs with latent CMV compared to CMV-seronegative RTRs (HR=3.1, P=0.005 and HR=2.0, P=0.002, respectively). After adjustment for potential confounders, latent CMV infection remained an independent risk factor for graft failure (HR=4.6, P=0.001), but not for mortality (HR=1.4, P=0.2).

Conclusions

Latent CMV is an independent risk factor for graft failure long after renal transplantation and carries a higher risk for graft failure than for mortality. These findings confirm the notion that latent CMV can be harmful in transplanted kidneys.

Long-term health and work outcomes of renal transplantation and patterns of work status during the end-stage renal disease trajectory

INTRODUCTION

The aim of this study was to examine the health- and work outcomes of renal transplant recipients long-term after transplantation as well as the pattern of work status, work ability and disability benefits during the end-stage renal disease (ESRD) trajectory that precedes transplantation.

METHODS

34 transplant recipients completed interviews 3, 13 months and >6 years posttransplantation. Health status (SF-36), work ability (WAI), and fatigue (CIS) were assessed by questionnaires, clinical data were derived from medical charts, and data on functional limitations were extracted from the social security system database. The work status trajectory preceding transplantation was examined retrospectively.

RESULTS

Of the 34 third wave transplant recipients, 29% were severely fatigued. Compared with the general working population, recipients experienced worse general health and less vitality. Non-working recipients had worse renal function and general health, and more limitations in physical functioning compared to working recipients. The WAI score indicated moderate work ability for 60% of the employed recipients. Although 67% were employed (45% parttime), 30% of those working still received some disability benefits. Social insurance physicians found variable levels of functional limitations. The mean work status trajectory showed more sickness absence and less work ability during dialysis, but after transplantation, both work status and work ability generally improved.

CONCLUSIONS

Transplant recipients have a compromised health status which leads to functional limitations and disability. Although work status improved after transplantation, a substantial number of the transplant recipients received disability benefits. The negative health consequences of anti-rejection medications may play an important role in long-term work ability. These results indicate that a 'new' kidney has advantages over dialysis with respect to work, but does not necessarily leads to 'normal' work outcomes.

Smoking is a risk factor for graft failure and mortality after renal transplantation

BACKGROUND

Smoking in renal transplant recipients (RTR) is an acknowledged cardiovascular risk factor. It is, however, unclear whether smoking also increases the risk of graft failure (GF).

METHOD

In this study, we prospectively assessed the association of current smoking versus past and never smoking with GF and mortality in 604 RTR (age 51.5 ± 12.1 years, 55% male).

RESULTS

At inclusion, 133 (22%) were current smokers, 255 (42%) were past smokers and 216 (36%) never smoked. During follow-up of 5.3 (4.7-5.7) years, 41 (7%) RTR experienced GF and 95 RTR (16%) died. Current smoking RTR had higher risk for GF compared to never smoking RTR (hazard ratio, HR = 3.3, 95% CI 1.5-7.1, p = 0.002). Past smoking RTR had similar risk of GF as never smoking RTR (HR = 1.1, 95% CI 0.5-2.6, p = 0.7). Current smoking RTR and past smoking RTR were at higher risk for death than never smoking RTR (HR = 2.1, 95% CI 1.1-3.8, p = 0.016, and HR = 2.4, 95% CI 1.4-4.0, p = 0.001, respectively).

CONCLUSION

Smoking after renal transplantation is associated with risk for GF and mortality. Since past smoking is a risk factor for mortality but not for GF, smoking cessation may be beneficial to RTR in delaying GF in long term.

Crosstalk between complement and Toll-like receptor activation in relation to donor brain death and renal ischemia-reperfusion injury

Two central pathways of innate immunity, complement and Toll-like receptors (TLRs), play an important role in the pathogenesis of renal injury inherent to kidney transplantation. Recent findings indicate close crosstalk between complement and TLR signaling pathways. It is suggested that mitogen activated protein kinases (MAPKs) might be the key molecules linking both the complement and TLR pathways together. Complement and TLRs are important mediators of renal ischemia-reperfusion injury (IRI). Besides IRI, complement C3 can also be upregulated and activated in the kidney before transplantation as a direct result of brain death (BD) in the donor. This local upregulation and activation of complement in the donor kidney has been proven to be detrimental for renal allograft outcome. Also TLR4 and several of its major ligands are upregulated by donor BD compared to living donors. Important and in line with the observations above, kidney transplant recipients have a benefit when receiving a kidney from a TLR4 Asp299Gly/Thr399Ile genotypic donor. The role of complement and TLRs and crosstalk between these two innate immune systems in relation to renal injury during donor BD and ischemia-reperfusion are focus of this review. Future strategies to target complement and TLR activation in kidney transplantation are considered.

Renal function equations before and after living kidney donation: a within-individual comparison of performance at different levels of renal function

BACKGROUND AND OBJECTIVES

The Modification of Diet in Renal Disease (MDRD) study equation and the Cockcroft-Gault (CG) equation perform poorly in the (near-) normal range of GFR. Whether this is due to the level of GFR as such or to differences in individual characteristics between healthy individuals and patient with chronic kidney disease (CKD) is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We evaluated the performance of MDRD, CG per BSA (CG/(BSA)) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations compared with measured GFR (mGFR; I-iothalamate) at 4 months before and 2 months after donation in 253 consecutive living kidney donors.

RESULTS

mGFR declined from 103 ± 15 to 66 ± 11 ml/min per 1.73 m(2) after donation. All equations underestimated mGFR at both time points. Arithmetic performance analysis showed improved performance after donation of all equations, with significant reduction of bias after donation. Expressed as percentage difference, mGFR-estimated GFR (eGFR) bias was reduced after donation only for CG/(BSA). Finally, in 295 unselected individuals who were screened for donation, mGFR was below the cutoff for donation of 80 ml/min per 1.73 m(2) in 19 individual but in 166, 98, and 74 for MDRD, CDK-EPI, and CG/(BSA), respectively.

CONCLUSIONS

A higher level of GFR as such is associated with larger absolute underestimation of true GFR by eGFR. For donor screening purposes, eGFR should be interpreted with great caution; when in doubt, true GFR should be performed to prevent unjustified decline of prospective kidney donors.

Body mass index and creatinine clearance are associated with steady-state serum concentrations of the cell damage marker S100B in renal transplant recipients

BACKGROUND

S100B is a prominent cell damage marker which can lead to sustained pro-inflammatory signaling. The aim was to investigate cross-sectional associations of steady-state S100B concentrations, particularly with C-reactive protein (CRP), in renal transplant recipients (RTRs) and also to investigate prospectively whether S100B would predict graft failure or mortality.

MATERIAL/METHODS

Outpatient RTRs with a graft functioning for >1 year were eligible for participation in this study. S100B was determined at baseline from serum. Mortality and the occurrence of graft failure were recorded until September 2007. Multivariable linear regression analyses were performed to identify potential determinants of S100B. Multivariable Cox regression analyses were performed to investigate S100B as a potential predictor of mortality or graft failure.

RESULTS

Five hundred eighty-one RTRs participated in the study. The median S100B concentration was 0.19 (0.14-0.25) microg/l. Recipient age (beta=0.009, p=0.02), body mass index (BMI) (beta=0.021, p<0.001), and creatinine clearance (beta=-015, p<0.001) were independently associated with S100B. During follow-up, 95 RTRs (16.4%) died and 41 (7.1%) developed graft failure. S100B levels did not predict mortality or graft failure.

CONCLUSIONS

BMI, creatinine clearance, and age are determinants of steady-state serum S100B concentrations in renal transplant recipients. The association of BMI with S100B suggests that S100B might be a new adipokine.

Gastrointestinal Symptoms in Kidney Transplant Recipients: What about Silent Sufferers?

Context

Transplantation improves health-related quality of life in patients with end-stage renal disease. However, primarily because of adverse effects of medication, among other gastrointestinal symptoms, health-related quality of life is not completely restored to normal. Although many patients have various gastrointestinal symptoms only a small proportion may be reported spontaneously.

Objective

To evaluate the prevalence of gastrointestinal symptoms in kidney transplant recipients, also the difference between spontaneously reported symptoms and symptoms elicited by specific questioning was assessed. The burden of these symptoms in daily life also was analyzed.

Design

A single-center, sequential, mixed method study to assess the difference between spontaneous patient reports of gastrointestinal symptoms and active screening by a questionnaire in kidney transplant patients.

Patients

In February 2008, patients received a questionnaire on gastrointestinal symptoms; notes in medical records were consulted for patients scoring less than 100. In June 2008, those patients received a second, extended questionnaire aimed to assess the burden of gastrointestinal symptoms in daily life.

Results

Ninety-two of 513 patients eventually proved to have gastrointestinal symptoms. Completed questionnaires were compared with notes in the patients' files of the past year. A total of 51 of these 92 patients appeared to have not mentioned their gastrointestinal symptoms during the outpatient clinic visits. Of these 51 patients, 37 reported a significant impact of gastrointestinal symptoms on daily life.

Conclusions

The silent sufferer exists. Specific questioning helps to improve communication concerning bothersome gastrointestinal symptoms. To assess the burden of these symptoms, a validated questionnaire should be developed.

Social participation after successful kidney transplantation

PURPOSE

To explore and describe the degree of social participation after kidney transplantation and to examine associated factors.

METHOD

A cross-sectional study on 239 adult patients 1-7.3 years after kidney transplantation was performed via in-home interviews on participation in obligatory activities (i.e., employment, education, household tasks) and leisure activities (volunteer work, assisting others, recreation, sports, clubs/associations, socializing, going out).

RESULTS

Kidney transplantation patients had a lower educational level, spent less time on obligatory activities, had part-time jobs more often, and participated less in sports compared to a control group from the general population. No difference was found in socializing, church attendance, volunteer work and going out. Multivariate regression analysis showed a negative association of age and a positive association of educational status and time since transplantation with obligatory participation. Multivariate logistic regression showed positive associations of education and time since transplantation with volunteer work; age was negatively and education positively associated with sports and going out, whereas living arrangement was also associated with going out.

CONCLUSIONS

Although kidney transplantation patients participate less in employment and sports, they do participate in household tasks, volunteer work, going out, socializing and other leisure activities. Participation is associated with factors as age, educational status and time since transplantation.

Vascular contraction and preeclampsia: downregulation of the Angiotensin receptor 1 by hemopexin in vitro

During normal pregnancy, in contrast to preeclampsia, plasma hemopexin activity is increased together with a decreased vascular angiotensin II receptor (AT(1)) expression. We now tested the hypothesis that hemopexin can downregulate the AT(1) receptor in vitro. Analysis of human monocytes or endothelial cells by flow cytometry showed decreased membrane density of AT(1) exclusively after incubation with active hemopexin, whereas in supernatants of these cell cultures, AT(1) molecules could be detected (dot blotting). Also, diminished AT(1) was observed in endothelial cell lysates after contact with hemopexin (Western blotting). Hemopexin also induced extracellular signal-regulated kinase 1/2 pathway inhibition in cells after stimulation with angiotensin II in vitro, indicating downregulation of AT(1) by hemopexin. In addition, functional loss of AT(1) occurred after incubation of rat aortic rings with active hemopexin, as reflected by decreased contraction of the aortic rings on stimulation with angiotensin II. It was further demonstrated that plasma from normal pregnant women decreased the AT(1) receptor expression on monocytes as compared with plasma from nonpregnant women or preeclamptic women. Finally, it was shown that plasma hemopexin activity increases during normal gestation from week 10 onward. We concluded that active hemopexin is able to downregulate the AT(1) receptor in human monocytes, endothelial cells, and rat aortic rings. We propose that the physiological role of enhanced hemopexin activity during healthy pregnancy is to downregulate the vascular AT(1) receptor, promoting an expanded vascular bed. Inhibition of hemopexin activity during preeclampsia may result in an enhanced AT(1) receptor expression and a contracted vascular bed.