An open-label phase 2 trial to assess the efficacy, safety and pharmacokinetics of lanthanum carbonate in hyperphosphatemic children and adolescents with chronic kidney disease undergoing dialysis.

BACKGROUND: This study assessed the efficacy, tolerability and pharmacokinetics (PK) of lanthanum carbonate (LC) in hyperphosphatemic children and adolescents with chronic kidney disease (CKD) undergoing dialysis. METHODS: This was a three-part, multicenter, open-label study of LC (oral powder formulation) in patients 10 to < 18 years old with CKD undergoing dialysis. In part 1, the single-dose PK of LC (500 mg, ≤12 years old; 1000 mg, > 12 years old) were summarized. In part 2, patients received calcium carbonate (CC [chewable tablet formulation]) (1500-6500 mg [total daily dose]) followed by LC (powder formulation) (1500-3000 mg [total daily dose]), or LC only (1500-3000 mg [total daily dose]), each for 8 weeks. During part 3, patients received LC (1500-3000 mg [total daily dose]) for up to 6 months. The primary efficacy endpoint was the proportion of LC-treated patients achieving serum phosphorus control after 8 weeks during parts 2 and/or 3, defined as: ≤1.94 mmol/L, < 12 years old; ≤1.78 mmol/L, ≥12 years old. Secondary efficacy endpoints included: the proportion of patients who achieved serum phosphorus control after 8 weeks of treatment with CC followed by 8 weeks of treatment with LC (with a washout period between treatments). The safety of LC and CC was also evaluated. RESULTS: In part 1, 20 patients received a single dose of LC. In part 2, 53 and 51 patients were treated with CC and LC for 8 weeks, respectively. During part 3, 42 patients received LC for up to 6 months. Most patients were white and male. For the primary efficacy endpoint, 50% (17/34) of patients who received LC for 8 weeks during parts 2 and/or 3 achieved serum phosphorus control. After 8 weeks of treatment with CC, 58.8% of patients achieved serum phosphorus control; after a subsequent washout period and 8 weeks of treatment with LC, 70.6% of patients achieved serum phosphorus control. Tmax and t1/2 occurred within 3-8 h and ~ 19 h, respectively; however, variability was observed. LC and CC were generally well tolerated. CONCLUSIONS: These data support the use of LC to manage hyperphosphatemia in pediatric patients with CKD undergoing dialysis. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01696279; EudraCT identifier: 2012-000171-17. Date of registration: 01/10/2012.

miR-21 antagonism reprograms macrophage metabolism and abrogates chronic allograft vasculopathy.

Despite much progress in improving graft outcome during cardiac transplantation, chronic allograft vasculopathy (CAV) remains an impediment to long-term graft survival. MicroRNAs (miRNAs) emerged as regulators of the immune response. Here, we aimed to examine the miRNA network involved in CAV. miRNA profiling of heart samples obtained from a murine model of CAV and from cardiac-transplanted patients with CAV demonstrated that miR-21 was most significantly expressed and was primarily localized to macrophages. Interestingly, macrophage depletion with clodronate did not significantly prolong allograft survival in mice, while conditional deletion of miR-21 in macrophages or the use of a specific miR-21 antagomir resulted in indefinite cardiac allograft survival and abrogated CAV. The immunophenotype, secretome, ability to phagocytose, migration, and antigen presentation of macrophages were unaffected by miR-21 targeting, while macrophage metabolism was reprogrammed, with a shift toward oxidative phosphorylation in naïve macrophages and with an inhibition of glycolysis in pro-inflammatory macrophages. The aforementioned effects resulted in an increase in M2-like macrophages, which could be reverted by the addition of L-arginine. RNA-seq analysis confirmed alterations in arginase-associated pathways associated with miR-21 antagonism. In conclusion, miR-21 is overexpressed in murine and human CAV, and its targeting delays CAV onset by reprogramming macrophages metabolism.

Novel immunological strategies for islet transplantation.

Islet transplantation has been demonstrated to improve glycometabolic control, to reduce hypoglycemic episodes and to halt the progression of diabetic complications. However, the exhaustion of islet function and the side effects related to chronic immunosuppression limit the spread of this technique. Consequently, new immunoregulatory protocols have been developed, with the aim to avoid the use of a life-time immunosuppression. Several approaches have been tested in preclinical models, and some are now under clinical evaluation. The development of new small molecules and new monoclonal or polyclonal antibodies is continuous and raises the possibility of targeting new costimulatory pathways or depleting particular cell types. The use of stem cells and regulatory T cells is underway to take advantage of their immunological properties and to induce tolerance. Xenograft islet transplantation, although having severe problems in terms of immunological compatibility, could theoretically provide an unlimited source of donors; using pigs carrying human immune antigens has showed indeed promising results. A completely different approach, the use of encapsulated islets, has been developed; synthetic structures are used to hide islet alloantigen from the immune system, thus preserving islet endocrine function. Once one of these strategies is demonstrated safe and effective, it will be possible to establish clinical islet transplantation as a treatment for patients with type 1 diabetes long before the onset of diabetic-related complications.

Role of podocyte B7-1 in diabetic nephropathy.

Podocyte injury and resulting albuminuria are hallmarks of diabetic nephropathy, but targeted therapies to halt or prevent these complications are currently not available. Here, we show that the immune-related molecule B7-1/CD80 is a critical mediator of podocyte injury in type 2 diabetic nephropathy. We report the induction of podocyte B7-1 in kidney biopsy specimens from patients with type 2 diabetes. Genetic and epidemiologic studies revealed the association of two single nucleotide polymorphisms at the B7-1 gene with diabetic nephropathy. Furthermore, increased levels of the soluble isoform of the B7-1 ligand CD28 correlated with the progression to ESRD in individuals with type 2 diabetes. In vitro, high glucose conditions prompted the phosphatidylinositol 3 kinase-dependent upregulation of B7-1 in podocytes, and the ectopic expression of B7-1 in podocytes increased apoptosis and induced disruption of the cytoskeleton that were reversed by the B7-1 inhibitor CTLA4-Ig. Podocyte expression of B7-1 was also induced in vivo in two murine models of diabetic nephropathy, and treatment with CTLA4-Ig prevented increased urinary albumin excretion and improved kidney pathology in these animals. Taken together, these results identify B7-1 inhibition as a potential therapeutic strategy for the prevention or treatment of diabetic nephropathy.

Inhibition of the purinergic pathway prolongs mouse lung allograft survival.

Lung transplantation has limited survival with current immunosuppression. ATP is released from activated T cells, which act as costimulatory molecules through binding to the purinergic receptor P2XR7. We investigated the role of blocking the ATP/purinergic pathway, primarily P2XR7, using its inhibitor oxidized ATP (oATP) in modulating rejection of mouse lung allografts. Mouse lung transplants were performed using mice with major histocompatibility complex mismatch, BALB/c to C57BL6. Recipients received suramin or oATP, and lung allografts were evaluated 15 to ≥ 60 days after transplantation. Recipients were also treated with oATP after the onset of moderate to severe rejection to determine its ability to rescue lung allografts. Outcomes measures included lung function, histology, thoracic imaging, and allo-immune responses. Blocking purinergic receptors with the nonselective inhibitor suramin or with the P2XR7-selective inhibitor oATP reduced acute rejection and prolonged lung allograft survival for ≥ 60 days with no progression in severity. There were fewer inflammatory cells within lung allografts, less rejection, and improved lung function, which was maintained over time. CD4 and CD8 T cells were reduced within lung allografts with impaired activation with prolonged impairment of CD8 responses. In vitro, oATP reduced CD8 activation of Th1 inflammatory cytokines IFN-γ and TNF-α and cytolytic machinery, granzyme B. Cotreatment with immunosuppressive agents, cyclosporine, rapamycin, or CTLA-4Ig resulted in no additive benefits, and oATP alone resulted in better outcomes than cyclosporine alone. This study illustrates a potential new pathway to target in hopes of prolonging survival of lung transplant recipients.

Long-term heart transplant survival by targeting the ionotropic purinergic receptor P2X7.

BACKGROUND: Heart transplantation is a lifesaving procedure for patients with end-stage heart failure. Despite much effort and advances in the field, current immunosuppressive regimens are still associated with poor long-term cardiac allograft outcomes, and with the development of complications, including infections and malignancies, as well. The development of a novel, short-term, and effective immunomodulatory protocol will thus be an important achievement. The purine ATP, released during cell damage/activation, is sensed by the ionotropic purinergic receptor P2X7 (P2X7R) on lymphocytes and regulates T-cell activation. Novel clinical-grade P2X7R inhibitors are available, rendering the targeting of P2X7R a potential therapy in cardiac transplantation. METHODS AND RESULTS: We analyzed P2X7R expression in patients and mice and P2X7R targeting in murine recipients in the context of cardiac transplantation. Our data demonstrate that P2X7R is specifically upregulated in graft-infiltrating lymphocytes in cardiac-transplanted humans and mice. Short-term P2X7R targeting with periodate-oxidized ATP promotes long-term cardiac transplant survival in 80% of murine recipients of a fully mismatched allograft. Long-term survival of cardiac transplants was associated with reduced T-cell activation, T-helper cell 1/T-helper cell 17 differentiation, and inhibition of STAT3 phosphorylation in T cells, thus leading to a reduced transplant infiltrate and coronaropathy. In vitro genetic upregulation of the P2X7R pathway was also shown to stimulate T-helper cell 1/T-helper cell 17 cell generation. Finally, P2X7R targeting halted the progression of coronaropathy in a murine model of chronic rejection as well. CONCLUSIONS: P2X7R targeting is a novel clinically relevant strategy to prolong cardiac transplant survival.

B7h (ICOS-L) maintains tolerance at the fetomaternal interface.

In a successful pregnancy, the semiallogeneic fetus is not rejected by the maternal immune system, which implies tolerance mechanisms protecting fetal tissues from maternal immune attack. Here we report that the ICOS-B7h costimulatory pathway plays a critical role in maintaining the equilibrium at the fetomaternal interface. Blockade of this pathway increased fetal resorption and decreased fetal survival in an allogeneic pregnancy model (CBA female × B6 male). Locally in the placenta, levels of regulatory markers such as IDO and TGF-ß1 were reduced after anti-B7h monoclonal antibody treatment, whereas levels of effector cytokines (eg, IFN-γ) were significantly increased. In secondary lymphoid organs, enhanced IFN-γ and granzyme B production (predominantly by CD8(+) T cells) was observed in the anti-B7h-treated group. The deleterious effect of B7h blockade in pregnancy was maintained only in CD4 knockout mice, not in CD8 knockout mice, which suggests a role for CD8(+) T cells in immune regulation by the ICOS-B7h pathway. In accord, regulatory CD8(+) T cells (in particular, CD8(+)CD103(+) cells) were significantly decreased after anti-B7h monoclonal antibody treatment, and adoptive transfer of this subset abrogated the deleterious effect of B7h blockade in fetomaternal tolerance. Taken together, these data support the hypothesis that B7h blockade abrogates tolerance at the fetomaternal interface by enhancing CD8(+) effector response and reducing local immunomodulation mediated by CD8(+) regulatory T cells.

An innovative artificial intelligence-based method to compress complex models into explainable, model-agnostic and reduced decision support systems with application to healthcare (NEAR).

BACKGROUND AND OBJECTIVE: In everyday clinical practice, medical decision is currently based on clinical guidelines which are often static and rigid, and do not account for population variability, while individualized, patient-oriented decision and/or treatment are the paradigm change necessary to enter into the era of precision medicine. Most of the limitations of a guideline-based system could be overcome through the adoption of Clinical Decision Support Systems (CDSSs) based on Artificial Intelligence (AI) algorithms. However, the black-box nature of AI algorithms has hampered a large adoption of AI-based CDSSs in clinical practice. In this study, an innovative AI-based method to compress AI-based prediction models into explainable, model-agnostic, and reduced decision support systems (NEAR) with application to healthcare is presented and validated. METHODS: NEAR is based on the Shapley Additive Explanations framework and can be applied to complex input models to obtain the contributions of each input feature to the output. Technically, the simplified NEAR models approximate contributions from input features using a custom library and merge them to determine the final output. Finally, NEAR estimates the confidence error associated with the single input feature contributing to the final score, making the result more interpretable. Here, NEAR is evaluated on a clinical real-world use case, the mortality prediction in patients who experienced Acute Coronary Syndrome (ACS), applying three different Machine Learning/Deep Learning models as implementation examples. RESULTS: NEAR, when applied to the ACS use case, exhibits performances like the ones of the AI-based model from which it is derived, as in the case of the Adaptive Boosting classifier, whose Area Under the Curve is not statistically different from the NEAR one, even the model's simplification. Moreover, NEAR comes with intrinsic explainability and modularity, as it can be tested on the developed web application platform (https://neardashboard.pythonanywhere.com/). CONCLUSIONS: An explainable and reliable CDSS tailored to single-patient analysis has been developed. The proposed AI-based system has the potential to be used alongside the clinical guidelines currently employed in the medical setting making them more personalized and dynamic and assisting doctors in taking their everyday clinical decisions.

Targeting the CXCR4-CXCL12 axis mobilizes autologous hematopoietic stem cells and prolongs islet allograft survival via programmed death ligand 1.

Antagonism of CXCR4 disrupts the interaction between the CXCR4 receptor on hematopoietic stem cells (HSCs) and the CXCL12 expressed by stromal cells in the bone marrow, which subsequently results in the shedding of HSCs to the periphery. Because of their profound immunomodulatory effects, HSCs have emerged as a promising therapeutic strategy for autoimmune disorders. We sought to investigate the immunomodulatory role of mobilized autologous HSCs, via target of the CXCR4-CXL12 axis, to promote engraftment of islet cell transplantation. Islets from BALB/c mice were transplanted beneath the kidney capsule of hyperglycemic C57BL/6 mice, and treatment of recipients with CXCR4 antagonist resulted in mobilization of HSCs and in prolongation of islet graft survival. Addition of rapamycin to anti-CXCR4 therapy further promoted HSC mobilization and islet allograft survival, inducing a robust and transferable host hyporesponsiveness, while administration of an ACK2 (anti-CD117) mAb halted CXCR4 antagonist-mediated HSC release and restored allograft rejection. Mobilized HSCs were shown to express high levels of the negative costimulatory molecule programmed death ligand 1 (PD-L1), and HSCs extracted from wild-type mice, but not from PD-L1 knockout mice, suppressed the in vitro alloimmune response. Moreover, HSC mobilization in PD-L1 knockout mice failed to prolong islet allograft survival. Targeting the CXCR4-CXCL12 axis thus mobilizes autologous HSCs and promotes long-term survival of islet allografts via a PD-L1-mediated mechanism.

[Novel immunological aspects of pediatric kidney transplantation]. / Nuovi aspetti immunologici del trapianto di rene in eta' pediatrica.

Pediatric kidney transplantation has been a serious challenge from the outset. The main reason lies in the immune system of children, which presents significant differences in terms of lymphocyte subpopulation distribution and alloimmune response activation from the adult immune system. These differences are greatest between neonates and adults, while they decrease in a linear and age-dependent fashion. In the past, kidney transplantation in children was a courageous initiative, given the poorer outcomes compared with adult recipients. Today, thanks to advances in therapy protocols and a better knowledge of the pediatric immune system, graft survival in pediatric patients has significantly improved and transplantation is the standard of care for the treatment of chronic organ failure in children. Moreover, there is growing interest in the field of pediatric transplantation because of the recipients' peculiar infective risk profile, the underestimated cardiovascular risk, and the necessity to identify both new non-invasive diagnostic techniques and the characteristics that make the pediatric immune system so peculiar. Acquiring new knowledge in those fields may slow down the adoption of new therapies but, on the other hand, it may represent a starting point to provide pediatric allograft recipients with diagnostic and therapeutic advantages and ultimately achieve allograft tolerance.

Immunomodulatory function of bone marrow-derived mesenchymal stem cells in experimental autoimmune type 1 diabetes.

Human clinical trials in type 1 diabetes (T1D) patients using mesenchymal stem cells (MSC) are presently underway without prior validation in a mouse model for the disease. In response to this void, we characterized bone marrow-derived murine MSC for their ability to modulate immune responses in the context of T1D, as represented in NOD mice. In comparison to NOD mice, BALB/c-MSC mice were found to express higher levels of the negative costimulatory molecule PD-L1 and to promote a shift toward Th2-like responses in treated NOD mice. In addition, transfer of MSC from resistant strains (i.e., nonobese resistant mice or BALB/c), but not from NOD mice, delayed the onset of diabetes when administered to prediabetic NOD mice. The number of BALB/c-MSC trafficking to the pancreatic lymph nodes of NOD mice was higher than in NOD mice provided autologous NOD-MSC. Administration of BALB/c-MSC temporarily resulted in reversal of hyperglycemia in 90% of NOD mice (p = 0.002). Transfer of autologous NOD-MSC imparted no such therapeutic benefit. We also noted soft tissue and visceral tumors in NOD-MSC-treated mice, which were uniquely observed in this setting (i.e., no tumors were present with BALB/c- or nonobese resistant mice-MSC transfer). The importance of this observation remains to be explored in humans, as inbred mice such as NOD may be more susceptible to tumor formation. These data provide important preclinical data supporting the basis for further development of allogeneic MSC-based therapies for T1D and, potentially, for other autoimmune disorders.

The IL-8-CXCR1/2 axis contributes to diabetic kidney disease.

AIMS/HYPOTHESIS: Inflammation has a major role in diabetic kidney disease. We thus investigated the role of the IL-8-CXCR1/2 axis in favoring kidney damage in diabetes. METHODS: Urinary IL-8 levels were measured in 1247 patients of the Joslin Kidney Study in type 2 diabetes (T2D). The expression of IL-8 and of its membrane receptors CXCR1/CXCR2 was quantified in kidney tissues in patients with T2D and in controls. The effect of CXCR1/2 blockade on diabetic kidney disease was evaluated in db/db mice. RESULTS: IL-8 urinary levels were increased in patients with T2D and diabetic kidney disease, with the highest urinary IL-8 levels found in the patients with the largest decline in glomerular filtration rate, with an increased albumin/creatine ratio and the worst renal outcome. Moreover, glomerular IL-8 renal expression was increased in patients with T2D, as compared to controls. High glucose elicits abundant IL-8 secretion in cultured human immortalized podocytes in vitro. Finally, in diabetic db/db mice and in podocytes in vitro, CXCR1/2 blockade mitigated albuminuria, reduced mesangial expansion, decreased podocyte apoptosis and reduced DNA damage. CONCLUSIONS/INTERPRETATION: The IL-8- CXCR1/2 axis may have a role in diabetic kidney disease by inducing podocyte damage. Indeed, targeting the IL-8-CXCR1/2 axis may reduce the burden of diabetic kidney disease.

Divergent role of donor dendritic cells in rejection versus tolerance of allografts.

Little is known about heart tissue/donor dendritic cells, which play a key role in mounting alloimmune responses. In this report, we focus on three primary features of donor dendritic cells: their generation, their trafficking after transplantation, and their role in regulating tolerance versus rejection. Using transgenic mice as donors of heart allografts enabled us to monitor trafficking of donor dendritic cells after transplantation. Donor dendritic cells rapidly migrated into secondary lymphoid tissues within 3 h of transplantation. We found that the chemokine receptor CX3CR1 regulates the generation of heart tissue dendritic cells constitutively. Compared with wild-type hearts, CX3CR1(-/-) hearts contained fewer dendritic cells, and heart allografts from CX3CR1(-/-) donors survived significantly longer without immunosuppression. Unexpectedly, though, co-stimulatory blockade with anti-CD154 or CTLA4-Ig induced long-term survival for wild-type heart allografts but not for CX3CR1(-/-) heart allografts. Increasing the dendritic cell frequency in CX3CR1(-/-) hearts by treatment with Flt3L restored the anti-CD154-induced prolongation of CX3CR1(-/-) heart allograft survival. Compared with wild-type donors, depleting transgenic donors of dendritic cells before heart transplantation also markedly worsened chronic rejection under anti-CD154 treatment. These data indicate the importance of the CX3CR1 pathway in the generation of heart tissue dendritic cells and the divergent role of tissue/dendritic cells in rejection versus tolerance.

Impact of pancreas transplantation on type 1 diabetes-related complications.

PURPOSE OF REVIEW: Type 1 diabetes is a chronic disease that can impact patient survival and quality of life because of acute and chronic complications. Although intensive insulin scheme treatment has been shown to reduce the incidence of diabetes-related complications, only pancreas transplantation has been shown to be able to alter them and in some cases to revert them. In this review, an extensive view of the effect of pancreas transplantation on diabetes-related complication will be described. RECENT FINDINGS: This review will focus on patients survival, diabetic nephropathy, neuropathy, cardiovascular event, comparing their incidence in type 1 diabetic patients treated with insulin and in type 1 diabetic patients receiving kidney, kidney-pancreas or pancreas alone graft. The review will focus mostly on the papers published in the last decade, with a particular attention to those on new aspects of graft function analysis like spectroscopy. Moreover, a comparison with islet transplantation procedure will be performed. SUMMARY: This review will give an update on the potential of pancreas transplantation, give a guide for clinical practice and help to consider pancreas transplantation as an alternative to insulin treatment for selected patients.

Characterization of donor dendritic cells and enhancement of dendritic cell efflux with CC-chemokine ligand 21: a novel strategy to prolong islet allograft survival.

Dendritic cells (DCs) are the most potent antigen-presenting cells, yet little data are available on the differential characteristics of donor and recipient DCs (dDCs and rDCs, respectively) during the process of islet allograft rejection. DTR-GFP-DC mice provide a novel tool to monitor DC trafficking and characteristics during allograft rejection. We show rapid migration of dDCs to recipient lymphoid tissues as early as 3 h post-islet allotransplantation. Compared with rDCs, dDCs express different patterns of chemokine receptors, display differential proliferative capacity, and exhibit a higher level of maturity; these findings could be attributed to the effects of injury that dDCs undergo during islet cell preparation and engraftment. Intriguingly, we detected dDCs in the spleen of recipients long after rejection of islet allografts. Given that dDCs express high levels of CCR7, islets were cultured before transplant with the ligand for CCR7 (CCL21). This novel method, which enabled us to enhance the efflux of dDCs from islet preparations, resulted in a prolongation of islet allograft survival in immunocompetent recipients. This study introduces dDCs and rDCs as two distinct types of DCs and provides novel data with clinical implications to use chemokine-based DC-depleting strategies to prolong islet allograft survival.

Phenotypic and functional differences between wild-type and CCR2-/- dendritic cells: implications for islet transplantation.

BACKGROUND: Trafficking of dendritic cells (DC), the primary regulators of alloimmune responses, is controlled by chemokines. Here, we provide evidence that lack of CCR2 could lead to the generation of functionally and phenotypically different DC, which in part could explain the benefits observed in transplanting islets in CCR2 recipients. METHODS AND RESULTS: We show that, in contrast to the in vitro DC maturation model, in vivo DC maturation is accompanied by an increase in the expression of CCR2. Compared with wild-type (WT), DC generated in vitro from CCR2 mice, and DC extracted from CCR2 naïve mice or from CCR2 recipients of islet allografts, display lesser allostimulatory capacity. Compared with WT DC, CCR2 DC produce more IL-4 and induce more IL-4-producing T cells. CCR2 DC also promote the generation of regulatory T cells that more efficiently suppress T cell proliferative responses by mixed leukocyte reaction. Similarly, the percentage of CD4CD25FoxP3 cells were found to be higher in CCR2 recipients of islet allografts than in WT recipients. CONCLUSIONS: In summary, lack of CCR2 interferes with the allostimulatory capacity of DC and promotes the generation of regulatory T cells. This is the first demonstration of a mechanistic link between targeting a specific chemokine pathway and the DC-regulatory T cell axis in alloimmunity.

Long-Term Mortality and Bone Safety in Patients with End-Stage Renal Disease Receiving Lanthanum Carbonate.

BACKGROUND/AIMS: This post-marketing observational study assessed the long-term safety of lanthanum carbonate (LaC) in US patients with end-stage renal disease (NCT00567723). METHODS: Patients (≥18 years old) undergoing dialysis, who had Medicare as their primary healthcare payer, and records in the United States Renal Data System were followed-up for 5 years. Patients who had received LaC for at least 12 consecutive weeks formed the exposed cohort. During the same time period, patients who had undergone dialysis for at least 12 consecutive weeks and had been treated with any other phosphate binder formed the primary comparator cohort. A historical cohort was also evaluated. Primary outcomes were all-cause mortality, and time to and incidence of first bone-fracture event requiring hospitalization. Secondary outcomes were time to first occurrence of and incidence of specific gastrointestinal (GI) disease, liver disease, malignancy, and major infectious episode requiring hospitalization. -Results: 2,026 and 8,094 patients were included in the exposed and primary comparator cohorts, respectively. A Cox proportional hazards model showed that patients receiving LaC were not at increased risk of all-cause mortality (adjusted hazard ratio 0.94; 95% CI 0.88-1.01; p = 0.078), bone fractures (0.86; 0.71-1.05; p = 0.130), specific GI disease (0.86; 0.76-0.97; p = 0.015), liver disease (0.88; 0.70-1.09; p = 0.236), malignancy (0.85; 0.54-1.34; p = 0.496), or major infectious episodes (0.87; 0.80-0.94; p < 0.001) requiring hospitalization compared with primary comparator patients. CONCLUSIONS: LaC was not associated with increased risk of mortality, bone fractures, or any secondary outcome.

P2X7R mutation disrupts the NLRP3-mediated Th program and predicts poor cardiac allograft outcomes.

Purinergic receptor-7 (P2X7R) signaling controls Th17 and Th1 generation/differentiation, while NOD-like receptor P3 (NLRP3) acts as a Th2 transcriptional factor. Here, we demonstrated the existence of a P2X7R/NLRP3 pathway in T cells that is dysregulated by a P2X7R intracellular region loss-of-function mutation, leading to NLRP3 displacement and to excessive Th17 generation due to abrogation of the NLRP3-mediated Th2 program. This ultimately resulted in poor outcomes in cardiac-transplanted patients carrying the mutant allele, who showed abnormal Th17 generation. Transient NLRP3 silencing in nonmutant T cells or overexpression in mutant T cells normalized the Th profile. Interestingly, IL-17 blockade reduced Th17 skewing of human T cells in vitro and abrogated the severe allograft vasculopathy and abnormal Th17 generation observed in preclinical models in which P2X7R was genetically deleted. This P2X7R intracellular region mutation thus impaired the modulatory effects of P2X7R on NLRP3 expression and function in T cells and led to NLRP3 dysregulation and Th17 skewing, delineating a high-risk group of cardiac-transplanted patients who may benefit from personalized therapy.

Islet-Derived eATP Fuels Autoreactive CD8+ T Cells and Facilitates the Onset of Type 1 Diabetes.

Extracellular ATP (eATP) activates T cells by engaging the P2X7R receptor. We identified two loss-of-function P2X7R mutations that are protective against type 1 diabetes (T1D) and thus hypothesized that eATP/P2X7R signaling may represent an early step in T1D onset. Specifically, we observed that in patients with newly diagnosed T1D, P2X7R is upregulated on CD8+ effector T cells in comparison with healthy control subjects. eATP is released at high levels by human/murine islets in vitro in high-glucose/inflammatory conditions, thus upregulating P2X7R on CD8+ T cells in vitro. P2X7R blockade with oxidized ATP reduces the CD8+ T cell-mediated autoimmune response in vitro and delays diabetes onset in NOD mice. Autoreactive CD8+ T-cell activation is highly dependent upon eATP/P2X7R-mediated priming, while a novel sP2X7R recombinant protein abrogates changes in metabolism and the autoimmune response associated with CD8+ T cells. eATP/P2X7R signaling facilitates the onset of autoimmune T1D by fueling autoreactive CD8+ cells and therefore represents a novel targeted therapeutic for the disorder.

Early increase of retinal arterial and venous blood flow velocities at color Doppler imaging in brittle type 1 diabetes after islet transplant alone.

Little information is currently available about the role of islet transplantation alone (ITA) on the retinal microcirculation. Our purpose was to investigate with color-Doppler-imaging the effect of ITA after one year on the blood flow velocities of central retinal artery and vein. Central retinal arteries and veins of both eyes of 10 ITA patients were evaluated with color-Doppler-imaging before and one year after transplant. Peak systolic velocity (psv), end diastolic velocity (edv) for arteries and maximum velocity (maxv), minimum velocity (minv) for veins were recorded and compared with a control group of type 1 diabetic patients. At one year, a statistically significant increase of blood flow velocities of central retinal arteries (psv: 6.09+/-0.46 vs. 10.12+/-1.20 cm/s, P=0.01) and veins (maxv: 3.12+/-0.28 vs. 6.12+/-1.00 cm/s, P=0.01) was found only in the ITA patients. An early, significant increase of arterial and venous retinal blood flow velocities was found after ITA.