PTFE grafts versus tunneled cuffed catheters for hemodialysis: which is the second choice when arteriovenous fistula is not feasible?

Vascular access-related complications are still one of the leading causes of morbidity in hemodialysis patients. The aim of this study was to compare polytetrafluoroethylene (PTFE) grafts versus tunneled cuffed permanent catheters (TCCs) in terms of vascular access and patients' survival. An observational study was carried out with a 2-year follow-up. Eighty-seven chronic hemodialysis patients were enrolled: 31 with a PTFE graft as vascular access for hemodialysis versus 56 with a TCC. Patients' mean age was 63.8 ± 14.6 (grafts) versus 73.5 ± 11.3 years (TCCs), P = 0.001. Significantly more patients with TCC had atrial fibrillation than patients with grafts (30.3% versus 6.5%, P = 0.01). In an unadjusted Kaplan-Meier analysis, median TCC survival at 24 months was 5.4 months longer than that of PTFE grafts but not significantly (log-rank test = 1.3, P = ns). In a Cox regression analysis adjusted for age, gender, number of previous vascular accesses, diabetes, atrial fibrillation, smoking, and any complication, this lack of significant difference in survival of the vascular access between TCC and PTFE groups was confirmed and diabetes proved to be an independent risk factor for the survival of both vascular accesses considered (P = 0.02). In an unadjusted Kaplan-Meier analysis, a higher mortality was found in the TCC group than in the PTFE group at 24 months (log-rank test = 10.07, P < 0.01). The adjusted Cox regression analysis showed that patients with TCC had a 3.2 times higher risk of death than patients with PTFE grafts. When an arteriovenous fistula (AVF) is not possible, PTFE grafts can be considered the vascular access of second choice, whereas TCCs can be used when an AVF or PTFE graft are not feasible or as a bridge to AVF or PTFE graft creation.

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.

Importance of vascular calcification in kidney transplant recipients.

BACKGROUND: Kidney transplantation is the treatment of choice for chronic kidney disease (CKD), but in kidney transplant recipients (KTRs) cardiovascular events are the first cause of death with a functioning graft, ranging from 36 to 55%. The impact of vascular calcification (VC) on morbidity and mortality of KTRs is not appreciated enough nowadays. SUMMARY: This review summarizes 13 important studies on VC in KTRs, comparing the results with CKD and dialysis populations. We focused on VC evaluation and use of coronary artery calcification (CAC) and aorta calcification (AoC) scores. We also evaluated the influence of traditional and non-traditional progression risk factors. KEY MESSAGES: VC strongly predicts cardiovascular events and all-cause mortality in KTRs. VC assessment is important in KTRs and based essentially on multislice computed tomography or electron beam computed tomography recognition of lesions. Quantitative measurement of CAC and AoC scores is essential for a correct definition of the calcium burden before and after kidney transplant. Progression of CAC slows down but does not halt after kidney transplant. A variable association of both traditional and non-traditional risk factors is shown. There is a strong association between baseline CAC score and CAC progression. A significant improvement in secondary hyperparathyroidism after transplantation favorably affects the progression of CAC. Low 25(OH)D3 levels are an independent determinant of CAC progression. Diabetes is a risk factor for the presence of CAC in KTRs, but has not been independently associated with CAC progression. The data published on the use of immunosuppressive drugs as progression factors are few and inconclusive.

Emerging drugs for chronic kidney disease.

INTRODUCTION: Chronic kidney disease (CKD) is a worldwide health problem. Despite remarkable headway in slowing the progression of kidney diseases, the incidence of end-stage renal disease (ESRD) is increasing in all countries with a severe impact on patients and society. The high incidence of diabetes and hypertension, along with the aging population, may partially explain this growth. Currently, the mainstay of pharmacological treatment for CKD, aiming to slow progression to ESRD are ACE inhibitors and angiotensin II receptor blockers for their hemodynamic/antihypertensive and anti-inflammatory/antifibrotic action. However, novel drugs would be highly desirable to effectively slow the progressive renal function loss. AREAS COVERED: Through the search engines, PubMed and ClinicalTrial.gov, the scientific literature was reviewed in search of emerging drugs in Phase II or III trials, which appear to be the most promising for CKD treatment. EXPERT OPINION: The great expectations for new drugs for the management of CKD over the last decade have unfortunately not been met. Encouraging results from preliminary studies with specific agents need to be tempered with caution, given the absence of consistent and adequate data. To date, several agents that showed great promise in animal studies have been less effective in humans.

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.

The efficacy and safety of cyclosporine reduction in de novo renal allograft patients receiving sirolimus and corticosteroids: results from an open-label comparative study.

This study evaluated the safety and efficacy of a sirolimus, corticosteroid, and cyclosporine reduction regimen in an open-label, 12-month trial of 420 de novo renal allograft recipients at 49 European transplant centers. One month post-transplantation, 357 patients were randomized to receive standard-dose cyclosporine (sCsA, n = 179) or reduced-dose cyclosporine (rCsA, n = 178). All patients also received sirolimus and corticosteroids. The primary end points were the rate of biopsy-confirmed acute rejection (BCAR) and renal function, as measured by serum creatinine. Baseline demographic and donor characteristics were similar between groups. BCAR rates at 12 months were not significantly different: 11.2% for rCsA patients and 16.2% for sCsA patients. Mean serum creatinine (±SEM) was significantly lower (1.75 ± 0.10 vs. 1.97 ± 0.07 mg/dl, P < 0.001), and creatinine clearance (±SEM; Nankivell method) was significantly higher (57.8 ± 1.78 vs. 49.5 ± 2.46 ml/min, P < 0.001) in patients receiving rCsA versus sCsA at 1 year, respectively. Patient and graft survival exceeded 98% in both groups. No significant differences in infection or malignancy were noted between groups. The rCsA with sirolimus and corticosteroid regimen resulted in excellent 12-month patient and graft survival, a low incidence of BCAR, and improved renal function in renal allograft recipients. Sirolimus administered with rCsA and corticosteroids provided adequate immunosuppression while reducing the potential for the nephrotoxic effects of cyclosporine. These findings may help to improve long-term renal allograft outcomes.

Extracorporeal detoxification for hepatic failure using molecular adsorbent recirculating system: depurative efficiency and clinical results in a long-term follow-up.

Acute liver failure and acute-on-chronic liver failure still show a poor prognosis. The molecular adsorbent recirculating system (MARS) has been extensively used as the most promising detoxifying therapy for patients with these conditions. Sixty-four patients with life-threatening liver failure were selected, and 269 MARS treatments were carried out as a bridge for orthotopic liver transplantation (OLT) or for liver function recovery. All patients were grouped according to the aim of MARS therapy. Group A consisted of 47 patients treated for liver function recovery (median age 59 years, range 23-82). Group B consisted of 11 patients on the waiting list who underwent OLT (median age 47 years, range 32-62). Group C consisted of 6 patients on the waiting list who did not undergo OLT (median age 45.5 years, range 36-54, P = 0.001). MARS depurative efficiency in terms of liver toxins, cytokines, and growth factors was assessed together with the clinical outcome of the patients during a 1-year follow-up. Total bilirubin reduction rate per session (RRs) for each MARS session was 23% (range 17-29); direct bilirubin RRs was 28% (21-35), and indirect bilirubin RRs was 8% (3-21). Ammonia RRs was 34% (12-86). Conjugated cholic acid RRs was 58% (48-61); chenodeoxycholic acid RRs was 34% (18-48). No differences were found between groups. Hepatocyte growth factor (HGF) values on starting MARS were 4.1 ng/mL (1.9-7.9) versus 7.9 ng/mL (3.2-14.1) at MARS end (P < 0.01). Cox regression analysis to determine the risk factors predicting patient outcomes showed that age, male gender, and Sequential Organ Failure Assessment score (but not Model for End-stage Liver Disease score) were factors predicting death, whereas the number of MARS sessions and the ΔHGF proved protective factors. Kaplan-Meier survival analysis was also used; after 12 months, 21.3% of patients in Group A survived, while 90.9% were alive in Group B and 16.7% in Group C (log rank = 0.002). In conclusion, MARS was clinically well tolerated by all patients and significantly reduced hepatic toxins. Better survival rates were linked to an OLT program, but patients' clinical characteristics on starting MARS therapy were the main factors predicting survival. The role of HGF should be evaluated in larger clinical trials.

Incidence and predictors of postoperative atrial fibrillation in kidney transplant recipients.

BACKGROUND: Postoperative atrial fibrillation (POAF) is a complication of cardiothoracic and noncardiothoracic surgery. Kidney transplant recipients bear several known risk factors and may have a higher incidence of POAF. We retrospectively studied kidney and kidney/liver transplant recipients to estimate their POAF incidence and identify relevant risk factors. We also adapted a clinical score originally designed to predict thromboembolic risk in atrial fibrillation (AF; CHA2DS2-VASc) for assessing transplant patients. METHODS: We reviewed the clinical charts of kidney or kidney/liver transplant recipients from January 2005 to December 2008 at St. Orsola University Hospital Kidney Transplant Centre. Patients with and without POAF were compared on a number of clinical, laboratory, and instrumental data. RESULTS: The POAF incidence in kidney transplant recipients was 8.2%. Risk factors for POAF identified in univariate analyses included older recipient age, history of myocardial infarction, history of AF, liver/kidney transplantation, arterial stiffness, atherosclerotic plaques in the aorta or lower limbs, and diabetes mellitus. In a multivariate analysis, age, myocardial infarction history and combined liver/kidney transplantation were significant independent predictors of POAF. The modified CHA2DS2-VASc score proved to have a better predictive validity that the original CHA2DS2-VASc (area under the curve=0.71, 95% confidence interval=0.63-0.79 vs. area under the curve=0.62, 95% confidence interval=0.52-0.73, respectively). CONCLUSION: AF is a notable complication of kidney, and particularly simultaneous liver/kidney, transplant surgery. Age, previous myocardial infarction, and simultaneous liver/kidney transplant independently predicted POAF. The modified CHA2DS2-VASc score could be useful to predict POAF risk in kidney transplant candidates.

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.

The relationship of NT-proBNP and dialysis parameters with outcome of incident haemodialysis patients: results from the membrane permeability outcome study.

BACKGROUND/AIMS: The association of raised levels of natriuretic peptides with elevated risk of mortality was investigated in the present analysis of the Membrane Permeability Outcome study. METHODS: N-terminal probrain type natriuretic peptide (NT-proBNP) was measured in 618 incident haemodialysis patients, randomised to either high-flux or low-flux. Characteristics of patients with NT-proBNP levels below or above the median were descriptively analysed and survival analysis was performed. RESULTS: Median NT-proBNP value was 2,124 pg/ml, with 1,854 pg/ml in the high-flux and 2,919 pg/ml in the low-flux group. Survival probability was lowest in patients with both a history of cardiovascular disease and NT-proBNP values above the median (p < 0.001). A multivariate Cox proportional hazard model showed interaction between presence of cardiovascular diseases and NT-proBNP levels above the median. CONCLUSIONS: NT-proBNP is an independent predictor of mortality also in incident haemodialysis patients. Lower concentrations associated with high-flux dialysis suggest a possible biological link to improved survival in this group.

Incidence and prevalence of cancer in kidney transplantation waiting list patients: an Italian experience.

INTRODUCTION: Evaluation of kidney transplant candidates is based on strict exclusion of major pathologies, such as neoplastic disease. The aim of this study is to evaluate epidemiological and clinical impact of tumor disease in an Italian renal transplant waiting list and to propose a screening schedule for neoplastic detection.
 MATERIALS AND METHODS: We retrospectively observed data of patients enrolled on the Emilia-Romagna kidney transplant waiting list between 1st August 2008 and 31st December 2010, evaluating the different causes of getting out from the list, the histologic type and incidence of cancer and the correlation between cancer onset and clinical features. The ratio of observed to expected cancer numbers (standardized incidence ratio, SIR), was estimated. RESULTS: We observed 2345 patients; 1297 got out from the waiting list; 57 of them (4,4%) got out because the onset of tumor. The overall incidence rate of cancer was 1354.8 (x 100,000 person-year) (1045.9 person-year in patients awaiting for first transplant(FT), 1851.5 person-year in patients awaiting for second transplant(ST)). The overall prevalence of cancer was 2,43% (2.2% in FT, 3.4% in ST) with a SIR of 1.8; In our population the prevalence of cancers related to ESKD was 52.6% with a SIR of 15.8.
 CONCLUSION: Kidney transplant waiting list patients present a higher incidence and prevalence of cancer compared to general population; it could be important to evaluate them for ESKD related malignancies because of their high incidence.

Effect of vitamin D receptor activator therapy on vitamin D receptor and osteocalcin expression in circulating endothelial progenitor cells of hemodialysis patients.

BACKGROUND: The effects of vitamin D receptor (VDR) and osteocalcin (OC) expression as well as VDR agonist (VDRA) therapy on circulating endothelial progenitor cells (EPCs) has not been elucidated yet. METHODS: We therefore analyzed EPCs in 30 healthy controls and 82 patients undergoing dialysis (no VDRA therapy: 28; oral calcitriol: 30, and intravenous paricalcitol, PCTA: 24). The percentage of EPCs (CD34+/CD133-/KDR+/CD45-) expressing VDR or OC, and VDR and OC expression defined by mean fluorescence intensity (MFI) were analyzed using flow cytometry. The in vitro effect of VDRAs was evaluated in EPCs isolated from each patient group. RESULTS: The percentage of VDR+ EPCs correlated positively with VDRA therapy and 25(OH)D, and negatively with diabetes, C-reactive protein, hemoglobin and osteopontin. VDR-MFI correlated positively with VDRA therapy, parathyroid hormone (PTH) and 25(OH)D, and negatively with diabetes and osteopontin. The percentage of OC+ EPCs correlated positively with the calcium score, PTH and phosphate, and negatively with 25(OH)D. OC-MFI correlated positively with calcium score, PTH, phosphate and hemoglobin, and negatively with albumin, 25(OH)D and osteopontin. Cell cultures from patients without VDRA therapy had the highest levels of calcium deposition and OC expression, which both significantly decreased following in vitro VDRA administration: in particular extracellular calcium deposition was only reduced by adding PCTA. CONCLUSIONS: Our data suggest that 25(OH)D serum levels and VDRA therapy influence VDR and OC expression on circulating EPCs. Since OC expression may contribute to vascular calcification, we hypothesize a putative protective role of VDRA therapy.

Prediction of three-year outcome of renal transplantation from optimal donors versus expanded criteria donors.

BACKGROUND/AIMS: The shortage in organ supply has required the use of expanded criteria donors (ECD) for kidney transplantation. Current pre-transplant evaluations of ECD organs are based on histological, clinical or mixed criteria. This monocentric study investigates the predictivity of Karpinski's histological score on 3-year graft function in renal transplant. Ex-post classification using Nyberg's score was carried out to assess the reliability of a purely clinical score and its applicability for organ allocation. METHODS: We evaluated 407 deceased donors (251 optimal and 156 ECD) for renal transplants performed between 2001 and 2006. The differences in creatinine levels and MDRD-GFR at transplant and 1, 2 and 3 years post-transplant between optimal donors and ECD were recorded. Amongst ECD organs, the effect of different Karpinski score classes (0-1, 2, 3, 4, double transplants) on 3-year graft outcomes was analyzed. We then compared renal function over time across the Nyberg grades (A, B, C, and D). RESULTS: Karpinski scores 0-1 and 2 and double transplants were associated with improved graft function compared to scores 3 and 4. Nyberg's clinical score shows a good fit with medium-term outcome and Karpinski's score, but among the donors with a high Nyberg grade (C and D), it fails to differentiate between allocable or non-allocable organs (due to Karpinski's score ≥7). CONCLUSIONS: Our data demonstrate a correlation of histological damage at the time of transplant with 3-year graft function, but at present we are unable to provide any supposition on the possible outcome of the discarded kidneys.

Tacrolimus-based, steroid-free regimens in renal transplantation: 3-year follow-up of the ATLAS trial.

BACKGROUND: Long-term use of corticosteroids is associated with considerable morbidity, including cardiovascular and metabolic adverse effects. METHODS: This study evaluated the long-term efficacy and safety of two steroid-free regimens compared with a triple immunosuppressive therapy in renal transplant recipients. This was a 3-year follow-up to a 6-month, open-label, randomized, multicenter study. RESULTS: Data from 3 years were available for 421 (93.3%) of 451 patients in the original intent-to-treat population (143 tacrolimus/basiliximab [Tac/Bas], 139 tacrolimus/mycophenolate mofetil [Tac/MMF], and 139 tacrolimus/MMF/steroids [triple therapy]). In the time interval from 6 months to 3 years after transplantation, the incidence of biopsy-proven acute rejection was low and similar (Tac/Bas, 2.1%; Tac/MMF, 2.2%; triple therapy, 2.2%); Most rejection episodes occurred during the first 6 months of the study. Graft survival was high (Kaplan-Meier estimates: 92.7%, 92.5%, and 92.5%), as was patient survival (93.1%, 96.4%, and 97.0%). There were 10 graft losses (n=2, 4, and 4) and 12 patient deaths (n=5, 2, and 5). Renal function was well preserved throughout the study and similar between groups. There was a trend toward improved cardiovascular risk factors in the Tac/Bas group, including reduced total and low-density lipoprotein cholesterol and lower new-onset insulin use. There were no between-group differences in the incidence or type of adverse events. CONCLUSION: Higher rates of acute rejection early in treatment were seen with the steroid-free regimens, but this did not translate into poorer long-term outcomes, such as graft and patient survival and renal function. A trend for a more favorable cardiovascular risk profile was observed for steroid-free immunosuppression with Tac/Bas.

Effect of a plasma sodium biofeedback system applied to HFR on the intradialytic cardiovascular stability. Results from a randomized controlled study.

BACKGROUND: Intradialytic hypotension (IDH) is still a major clinical problem for haemodialysis (HD) patients. Haemodiafiltration (HDF) has been shown to be able to reduce the incidence of IDH. METHODS: Fifty patients were enrolled in a prospective, randomized, crossover international study focussed on a variant of traditional HDF, haemofiltration with endogenous reinfusion (HFR). After a 1-month run-in period on HFR, the patients were randomized to two treatments of 2 months duration: HFR (Period A) or HFR-Aequilibrium (Period B), followed by a 1-month HFR wash-out period and then switched to the other treatment. HFR-Aequilibrium (HFR-Aeq) is an evolution of the haemofiltration with endogenous reinfusion (HFR) dialysis therapy, with dialysate sodium concentration and ultrafiltration rate profiles elaborated by an automated procedure. The primary end point was the frequency of IDH. RESULTS: Symptomatic hypotension episodes were significantly lower on HFR-Aeq versus HFR (23 ± 3 versus 31 ± 4% of sessions, respectively, P l= l0.03), as was the per cent of clinical interventions (17 ± 3% of sessions with almost one intervention on HFR-Aeq versus 22 ± 2% on HFR, P <0.01). In a post-hoc analysis, the effect of HFR-Aeq was greater on more unstable patients (35 ± 3% of sessions with hypotension on HFR-Aeq versus 71 ± 3% on HFR, P <0.001). No clinical or biochemical signs of Na/water overload were registered during the treatment with HFR-Aeq. CONCLUSIONS: HFR-Aeq, a profiled dialysis supported by the Natrium sensor for the pre-dialysis Na(+) measure, can significantly reduce the burden of IDH. This could have an important impact in every day dialysis practice.

Mesenchymal stem cells and islet cotransplantation in diabetic rats: improved islet graft revascularization and function by human adipose tissue-derived stem cells preconditioned with natural molecules.

Hypoxia plays an important role in limiting the engraftment, survival, and function of intrahepatically transplanted islets. Mesenchymal stem cells (MSCs) were recently used in animal models of islet transplantation not only to reduce allograft rejection but also to promote revascularization. Among different possible origins, adipose tissue represents a novel and good source of MSCs. Moreover, the capability of adipose tissue-derived stem cells (ASCs) to improve islet graft revascularization was recently reported after hybrid transplantation in mice. Within this context, we have previously shown that hyaluronan esters of butyric and retinoic acids can significantly enhance the rescuing potential of human MSCs (hMSCs). Here we evaluated whether ex vivo preconditioning of human ASCs (hASCs) with a mixture of hyaluronic (HA), butyric (BU), and retinoic (RA) acids may result in optimization of graft revascularization after islet/stem cell intrahepatic cotransplantation in syngeneic diabetic rats. We demonstrated that hASCs exposed to the mixture of molecules are able to increase the secretion of vascular endothelial growth factor (VEGF) as well as the transcription of angiogenic genes, including VEGF, KDR (kinase insert domain receptor), and hepatocyte growth factor (HGF). Rats transplanted with islets cocultured with preconditioned hASCs exhibited a better glycemic control than rats transplanted with an equal volume of islets and control hASCs. Cotransplantation with preconditioned hASCs was also associated with enhanced islet revascularization in vivo, as highlighted by graft morphological analysis. The observed increase in islet graft revascularization and function suggests that our method of stem cell preconditioning may represent a novel strategy to remarkably improve the efficacy of islets-hMSCs cotransplantation.

Group I nonreciprocal inhibition in restless legs syndrome secondary to chronic renal failure.

BACKGROUND: Neurophysiological investigations disclosed spinal cord hyperexcitability in primary restless legs syndrome (p-RLS). Uremic RLS (u-RLS) is the most common secondary form, but its pathophysiological mechanisms remain unsettled. Aim of this study was to explore spinal cord excitability by evaluating group I nonreciprocal (Ib) inhibition in u-RLS patients in comparison with p-RLS patients and healthy subjects. METHODS: Eleven u-RLS patients undergoing long-term hemodialysis treatment, nine p-RLS patients and ten healthy subjects were studied. Soleus H reflex latency (HR-L), H(max)/M(max) ratio, and Ib inhibition were evaluated. Ib inhibition was tested measuring the amplitude changes in soleus H reflex following stimulation of the synergist gastrocnemius medialis (GM) nerve at rest. Nerve conduction studies were performed in the uremic patients. RESULTS: The H(max)/M(max) ratio did not differ in the three groups. The u-RLS patients showed a normal Ib inhibition comparable with the healthy group, whereas the p-RLS group had evidence of a reduced active inhibition compared with both u-RLS patients (P = 0.04) and controls (P = 0.007), prominently at 5 ms (P = 0.007) and at 6 ms (P = 0.02) of conditioning-test interval. Neurophysiological examination disclosed abnormalities ranging from higher HR-L to clear-cut polyneuropathy in most u-RLS patients. CONCLUSIONS: Unlike p-RLS patients, u-RLS patients had normal Ib inhibition, suggesting a regular supraspinal control of Ib spinal interneurons. Subclinical peripheral nerve abnormalities were detected in most uremic patients. Peripherally disrupted sensory modulation may represent the major pathophysiological determinant of uremic RLS.

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.