Vania Cuna

Hepatorenal syndrome: Update on diagnosis and treatment

Acute kidney injury (AKI) is a common complication in patients with end-stage liver disease and advanced cirrhosis regardless of the underlying cause. Hepatorenal syndrome (HRS), a functional form of kidney failure, is one of the many possible causes of AKI. HRS is potentially reversible but involves highly complex pathogenetic mechanisms and equally complex clinical and therapeutic management. Once HRS has developed, it has a very poor prognosis. This review focuses on the diagnostic approach to HRS and discusses the therapeutic protocols currently adopted in clinical practice.

VDR Expression on Circulating Endothelial Progenitor Cells in Dialysis Patients Is Modulated by 25(OH)D Serum Levels and Calcitriol Therapy

Background/Aims: Vitamin D deficiency is associated with endothelial dysfunction in uremic patients, possibly by the impairment in the number and function of endothelial progenitor cells (EPCs). In 89 hemodialysis patients, we investigated the factors associated with the number of circulating EPCs (CD34⁺/CD133⁺/KDR⁺ and CD34⁺/CD133^–/KDR⁺ cells), the presence of VDR and the determinants of VDR expression on EPCs, in particular in calcitriol therapy. Methods: EPC counts, percentages of VDR-positive EPCs and VDR expression were assessed by flow cytometry. Cells isolated from a subgroup of patients were cultured to analyze colony-forming units, specific markers expression and a capillary-like structure formation. Results/Conclusions: Our study demonstrates the presence of VDR on EPCs. In our dialysis patients, the parameters studied on both CD34⁺/CD133⁺/KDR⁺ and CD34⁺/CD133^–/KDR⁺ cells, in particular VDR expression, seem to be influenced by uremia-related factors, including anemia, inflammation, diabetes, 25(OH)D serum levels and calcitriol therapy.

Neutrophil Gelatinase-Associated Lipocalin Increases HLA-G+/FoxP3+ T-Regulatory Cell Population in an In Vitro Model of PBMC

Background Neutrophil gelatinase-associated lipocalin (NGAL) is emerging as a mediator of various biological and pathological states. However, the specific biological role of this molecule remains unclear, as it serves as a biomarker for many conditions. The high sensitivity of NGAL as a biomarker coupled with relatively low specificity may hide important biological roles. Data point toward an acute compensatory, protective role for NGAL in response to adverse cellular stresses, including inflammatory and oxidative stress. The aim of this study was to understand whether NGAL modulates the T-cell response through regulation of the human leukocyte antigen G (HLA-G) complex, which is a mediator of tolerance. Methodology/Principal Findings Peripheral blood mononuclear cells (PBMCs) were obtained from eight healthy donors and isolated by centrifugation on a Ficoll gradient. All donors gave informed consent. PBMCs were treated with four different concentrations of NGAL (40–320 ng/ml) in an iron-loaded or iron-free form. Changes in cell phenotype were analyzed by flow cytometry. NGAL stimulated expression of HLA-G on CD4+ T cells in a dose- and iron-dependent manner. Iron deficiency prevented NGAL-mediated effects, such that HLA-G expression was unaltered. Furthermore, NGAL treatment affected stimulation of regulatory T cells and in vitro expansion of CD4+ CD25+ FoxP3+ cells. An NGAL neutralizing antibody limited HLA-G expression and significantly decreased the percentage of CD4+ CD25+ FoxP3+ cells. Conclusions/Significance We provide in vitro evidence that NGAL is involved in cellular immunity. The potential role of NGAL as an immunomodulatory molecule is based on its ability to induce immune tolerance by upregulating HLA-G expression and expansion of T-regulatory cells in healthy donors. Future studies should further evaluate the role of NGAL in immunology and immunomodulation and its possible relationship to immunosuppressive therapy efficacy, tolerance induction in transplant patients, and other immunological disorders.

Role of the hemodialysis vascular access type in inflammation status and monocyte activation

Purpose The aim of this study was to ascertain the role of different vascular access types in inflammatory status, monocyte activation, and senescence in hemodialysis patients. Methods We recruited 126 hemodialysis patients, including 51 with arterovenous fistula (AVF), 32 with arterovenous graft (AVG), and 43 with tunneled cuffed catheters (TCC). In dialysis patients enrolled in the study and in a control group of 40 healthy subjects, we measured the serum levels of albumin, CRP, IL-6, and TNF-α, the expression of CD14, CD44, and CD32 on monocyte surface, and the percentage of monocytes exhibiting a senescent phenotype (CD14+CD32+). Results The patients with AVG compared to those with AVF had: a) higher levels of CRP and TNF-α; b) increased expression of CD14 and CD32 on monocyte surface, with no difference in CD44 expression; c) no difference in the percentage of CD14+CD32+ monocytes. In the comparison of TCC vs. AVF group, we observed significantly higher values of: a) circulating inflammatory markers (CRP, IL-6, TNF-α); b) monocyte surface expression of cellular activation markers (CD14, CD44 and CD32); c) relative count of CD14+CD32+ monocytes. When comparing TCC vs. AVG group, we found: a) no difference in serum levels of CRP, IL-6, and TNF-α; b) no difference in the expression of CD14, CD44, and CD32 on monocyte surface; c) no difference in the percentage of CD14+CD32+ monocytes. Conclusions These results suggest that the use of AVG and TCC for dialysis vascular access is associated with serological and cellular indexes of inflammatory reaction, also resulting in a higher degree of monocyte activation and senescence.

Effects of unfractioned heparin and low-molecular-weight heparin on osteoprotegerin and RANKL plasma levels in haemodialysis patients

BACKGROUND This randomized crossover study investigated the effects of unfractioned heparin (UFH) and low-molecular-weight heparin (LMWH) on intra- and post-dialytic blood levels of osteoprotegerin (OPG), receptor activator of nuclear factor kappa B ligand (RANKL) and inflammatory cytokines. METHODS Forty patients on haemodialysis for at least 12 months were selected. UFH or LMWH was randomly assigned and maintained for 1 month, and then, in the following month, each patient was switched to the other form of heparin. In the mid-week session, we determined the changes in anti-Xa activity, OPG, RANKL, IL-1β, IL-6 and TNF-α values before heparin administration and after 15 min, 4, 8 and 24 h (T0, T1, T2, T3 and T4 respectively). Since these parameters at the various experimental times showed a non-normal distribution, log transformation was applied in order to run parametric ANOVA, with Bonferroni correction for multiple comparisons. RESULTS The changes in anti-Xa activity over time were similar but not the same for the UFH and LMWH. A highly significant (P<0.001) increase in anti-Xa activity was detected at T1, regardless of the type of heparin, as confirmed in the comparison of T0 vs T1 using one-way ANOVA. Moreover, with both heparins, significant differences were found in the comparisons of anti-Xa activity at T1 vs T2 (both P<0.001) and at T2 vs T3 (P=0.0003 with UFH; P<0.001 with LMWH). Conversely, the difference in anti-Xa activity at T3 vs T4 was still significant with UFH (P=0.0186) but not significant with LMWH (P=0.728). When comparing anti-Xa activity at T4 vs T0, no significant differences were found either with UFH (P=0.1996) or with LMWH (P=0.7470), thus indicating that 24 h after heparin infusion, anti-Xa activity returned back to the pre-infusion values. When we analysed the changes in OPG levels over time, we found that the administration of heparin, regardless of the type, determined an increase in circulating OPG with a zenith at 15 min (T1), with a return back to the baseline levels within the 24th hour post-infusion. One-way ANOVA revealed significant differences in OPG blood levels at T0 vs T1 with both UFH (P=0.0112) and LMWH (P=0.0288), whereas no significant difference was observed in the comparisons of OPG levels at T1 vs T2, T2 vs T3, T3 vs T4 and T4 vs T0, either with UFH or with LMWH. The circulating levels of RANKL, IL-1β, IL-6 and TNF-α at the different intra- and post-dialytic times did not show significant variations following heparin administration, either with UFH or with LMWH. One-way ANOVA performed on the log-transformed values of RANKL, IL-1β, IL-6 and TNF-α at the various experimental times (T0 vs T1, T1 vs T2, T2 vs T2, T3 vs T4 and T4 vs T0) revealed no significant intra- and post-dialytic changes in their blood levels, thus confirming that heparin infusion did not affect their blood levels. CONCLUSIONS These results suggest that heparin-regulated cyclic increases of OPG might play a role in the vascular pathology of haemodialysis patients.

Renal transplant in patients with polycystic disease: the Italian experience.

We analyzed the results of kidney transplantation in autosomal dominent polycystic kidney disease (ADPKD) patients in Italy, including 14,305 transplantations performed from January 2002 to December 2010, including: 12,859 first single or double kidneys from cadaveric donors (13% polycystic), 172 combined liver-kidney cases (22% polycystic), and 1,303 living-donor organs (7% polycystic). Among the first transplantations (12,008 single, 851 double), with follow-ups ranging from 16 to 120 months, polycystic patients demonstrated better graft survival compared with other kidney diseases (86% vs 82% at 5 years; P < .01); mortality was not different (92% vs 79% at 1 year). A better trend was obtained also among combined liver-kidney transplantations in ADPKD. Regarding pretransplantation management of polycystic patients, we noticed a conservative attitude in 32/35 transplant centers. The main indication for nephrectomy was for the lack of abdominal space. Regarding instrumental studies, 86% of centers asked for second-level investigations computerized tomography for kidney dimensions. Radiologic investigations for vasculocerebral malformations were required in 97% of the centers: 74% as a routine and 23% in the presence of familial history of cerebral hemorrhage. Polycystic patients are good candidates for kidney transplantation with correct management before transplantation.

Thrombosis of Tunneled-Cuffed Hemodialysis Catheters: Treatment With High-Dose Urokinase Lock Therapy

Thrombosis-related malfunction of tunneled-cuffed central venous catheters (TCC) for hemodialysis (HD) currently leads to a high rate of untimely catheter removal. Urokinase (UK) therapy is used for TCC thrombosis/malfunction, but no consensus exists on the adequate dose to obtain thrombolysis. We selected 72 HD patients with TCC and a mean age and HD vintage of 74 years (range 65-87) and 36 months (range 12-61), respectively. All patients received warfarin therapy with a target international normalized ratio (INR) of 1.8-2.5. Coagulative assessment of the patients was obtained by checking the INR, activated partial thromboplastin time, fibrinogen, hemoglobin, and platelets. Sixty-five thrombotic events were recorded during a 3-year follow-up (median 0.3 events/patient/year). The patients selected were randomized into two groups according to a different thrombolytic therapy. Group A comprised 29 thrombotic events in 32 patients who received UK 25,000 IU in both arterial and venous lines of the TCC for each event. UK restored an adequate blood flow rate (BFR) for HD (≥ 250 mL/min) in 4/29 events (13.7%), whereas addition of 50,000 IU to both arterial and venous lines was required in 25/29 events (86.3%). For the same 25 events in the second HD session, a further 75,000 IU of UK was needed for each TCC lumen. Group B comprised 36 thrombotic events in 40 patients who received 100 000 IU of UK in the arterial and venous lumen of the TCC for each event. An adequate BFR was recovered in all events. In 12/36 events (33.3%), 100,000 IU UK for both lumens were needed in the second HD. In conclusion, group B patients obtained (i) a significantly better TCC patency than group A patients; (ii) a low UK administration in the following HD sessions; and (iii) no bleeding complications.

Physical Activity in Solid Organ Transplant Recipients: Preliminary Results of the Italian Project

Background/Aims: The role of physical activity in transplanted patients is often underestimated. We discuss the Italian National Transplant Centre experience, which started in 2008 studying transplanted patients involved in sports activities. The study was then developed through a model of cooperation between surgeons, sports physicians and exercise specialists. Methods: A multicentre study was realized in 120 transplanted patients of which 60 treated with supervised physical activity (three sessions/week of aerobic and strengthening exercises) and 60 controls. We present the results of the first 26 patients (16 males, 10 females; 47.8±10.0 years; 21 kidney, 5 liver transplanted; time from transplant 2.3±1.4 years) who completed 12 months of supervised physical activity. Results: Data showed an increase of peak aerobic power (t=4.535; P<0.01) and maximum workload (t=4.665; P<0.01) in the incremental cycling test. Maximum strength of knee extensors (t=2.933; P<0.05) and elbow flexors (t=2.450; P<0.05), and the power of lower limb (t=2.303; P<0.05) significantly increases. Health Related Quality of Life showed a significant improvement. Serum creatinine (1.4±0.5 vs 1.3±0.4 mg/dL) and proteinuria (0.10±0.14 vs 0.08±0.08 gr/dL) were stable. Conclusion: These preliminary results confirm the positive effects of supervised physical exercise. It can be considered as an input to promote other detailed exercise protocols.

Incidence of Late Deep Venous Thrombosis Among Renal Transplant Patients

BACKGROUND Kidney transplant recipients (KTRs) manifest hypercoagulable state that contributes to an increased incidence of deep vein thrombosis (DVT), not only early but also late in their course. KTRs display an imbalance of hemostatic mechanisms with a multifactorial rise in procoagulant factors, partly related to traditional risk factors and partly to transplantation. The aim of this study was to evaluate the incidence of first episodes of DVT among KTRs, focusing on risk factors. METHODS From 2008 to 2011, we evaluated 30 kidney transplant patients who ≥4 months there after transplantation developed DVT in the lower limbs only, lower limbs complicated by pulmonary embolism or retinal thrombosis. We analyzed causes of primary nephropathy, immunosuppressive regimen, post-transplantation infections, and erythrocytosis. DVT was diagnosed by color Doppler ultrasound or eye examination. RESULTS A significantly increased incidence of DVT was observed among patients receiving cyclosporine or cyclosporine + mammalian target of rapamycin inhibitors, affected by polycystic kidney diseases, systemic lupus erythematosus or nephrotic syndrome, or displaying rapid and/or excessive correction of hematocrit values. DVT was not significantly related to an acute infection (cytomegalovirus) or to the prior dialysis modality. CONCLUSIONS Hypercoagulability is a multifactorial condition in KTRs, representing a severe complication in stable patients. Prevention may consist of either accurate pretransplantation screening for thrombophilia or identification of patients at higher DVT risk.

The impact of apoptosis and inflammation gene polymorphisms on transplanted kidney function

BACKGROUND The progressive deterioration of kidney allograft function leads in most cases to transplant failure. Polymorphisms in genes encoding for inflammatory and apoptosis molecules may be one possible explanation for interindividual differences in kidney transplant outcomes. The objective of our work was to identify the possible effect of interleukin 6 (IL-6), transforming growth factor beta 1 (TGFB1), and Fas on graft function. MATERIAL AND METHODS A case-control study was carried out to assess potential associations between polymorphisms in inflammation- and apoptosis-related genes and the risk for chronic impairment of kidney graft function. The study included 376 cadaveric kidney recipients, 256 of them with stable graft function and 120 who experienced renal deterioration during the follow-up period of 2.6 ± 1.4 years. Genotyping of IL-6/G-174C, TGFB1/L10P, TGFB1/R25P, and Fas/G-670A polymorphisms was performed by PCR-RFLP and direct sequencing. RESULTS Considering the single IL-6, TGFB1, and Fas polymorphisms, we found similar allelic and genotype frequencies between the 2 groups. To test the hypothesis of mutual effects of polymorphisms, multiple logistic regression was performed incorporating data for all the possible dual genotypic associations. The association of IL-6 high producer and Fas low producer genotype resulted in a protective effect against graft dysfunction (OR=0.79; 95% C.I.=0.72-0.86). CONCLUSIONS This study did not find significant associations of apoptosis and inflammation gene polymorphisms with transplanted kidney function in Italian renal transplant recipients. However, our data seem to indicate that the carriage of IL-6 high producer/Fas low producer genotype has a protective effect against graft function loss.