Predicting Cellular Rejection of Renal Allograft Based on the Serum Proteomic Fingerprint.

Kidney transplantation is an essential medical procedure that significantly enhances the survival rates and quality of life for patients with end-stage kidney disease. However, despite advancements in immunosuppressive therapies, allograft rejection remains a leading cause of organ loss. Notably, predictions of cellular rejection processes primarily rely on biopsy analysis, which is not routinely performed due to its invasive nature. The present work evaluates if the serum proteomic fingerprint, as acquired by Fourier Transform Infrared (FTIR) spectroscopy, can predict cellular rejection processes. We analyzed 28 serum samples, corresponding to 17 without cellular rejection processes and 11 associated with cellular rejection processes, as based on biopsy analyses. The leave-one-out-cross validation procedure of a Naïve Bayes model enabled the prediction of cellular rejection processes with high sensitivity and specificity (AUC > 0.984). The serum proteomic profile was obtained in a high-throughput mode and based on a simple, rapid, and economical procedure, making it suitable for routine analyses and large-scale studies. Consequently, the current method presents a high potential to predict cellular rejection processes translatable to clinical scenarios, and that should continue to be explored.

Biochemical Clusters as Substitutes of Bone Biopsies in Kidney Transplant Patients.

Bone and mineral metabolism abnormalities are frequent in kidney transplant recipients and have been associated with cardiovascular morbidity. The primary aim of this study was to analyse the association between routine clinically available biochemical evaluation, non-routine histomorphometric bone evaluation, and vascular disease in kidney transplanted patients. A cross-sectional analysis was performed on 69 patients, 1-year after kidney transplantation. Laboratory analysis, radiography of hands and pelvis, bone biopsy, bone densitometry, and coronary CT were performed. One-year post-transplantation, nearly one-third of the patients presented with hypercalcemia, 16% had hypophosphatemia, 39.3% had iPTH levels > 150 pg/mL, 20.3% had BALP levels > 40 U/L, and 26.1% had hypovitaminosis D. Evaluation of extraosseous calcifications revealed low Adragão and Agatston scores. We divided patients into three clusters, according to laboratory results routinely used in clinical practice: hypercalcemia and hyperparathyroidism (Cluster1); hypercalcemia and high BALP levels (Cluster2); hypophosphatemia and vitamin D deficiency (Cluster 3). Patients in clusters 1 and 2 had higher cortical porosity (p = 0.001) and osteoid measurements, although there was no difference in the presence of abnormal mineralization, or low volume. Patients in cluster 2 had a higher BFR/BS (half of the patients in cluster 2 had high bone turnover), and most patients in cluster 1 had low or normal bone turnover. Cluster 3 has no differences in volume, or turnover, but 60% of the patients presented with pre-osteomalacia. All three clusters were associated with high vascular calcifications scores. Vascular calcifications scores were not related to higher bone mineral density. Instead, an association was found between a higher Adragão score and the presence of osteoporosis at the femoral neck (p = 0.008). In conclusion, inferring bone TMV by daily clinical biochemical analysis can be misleading, and bone biopsy is important for assessing both bone turnover and mineralization after kidney transplantation, although hypophosphatemia combined with vitamin D deficiency is associated with abnormal mineralization. The presence of hypercalcemia with high levels of PTH or high levels of BALP, or hypophosphatemia and vitamin D deficiency should remind us to screen vascular calcification status of patients.Clinical Research: ClinicalTrials.gov ID NCT02751099.

Adenovirus Infection in a Kidney-Pancreatic Transplant Recipient: Case Report.

Adenovirus infection in transplant recipients may present from asymptomatic viremia to multisystemic involvement. Most frequently, it occurs in the first year after a kidney transplant, and it is secondary to the reactivation of latent disease. However, primary infection may occur, and disseminated disease is more common when related to primary infection. Kidney involvement may be confirmed by biopsy, although diagnosis may be presumptive. Reduction of immunosuppression and supportive care are important components of therapy. CASE DESCRIPTION: A 41-year-old female renal-pancreatic recipient 12 years before with chronic renal graft dysfunction and a functional pancreatic graft had a history of cytomegalovirus and polyoma virus infection 2 years after transplantation. She was taking tacrolimus, mycophenolate mofetil, and prednisolone. The patient was admitted after persistent uncharacteristic diarrhea 3 weeks before hospitalization without any relevant epidemiologic context. She was dehydrated, and the lab results showed worsened kidney function and leucocytosis. The viral culture revealed adenovirus. Vigorous hydration was implemented, and the mycophenolate mofetil dose was reduced. The patient was discharged, and renal function returned to previous values. DISCUSSION AND CONCLUSION: Adenovirus infection has a wide clinical presentation, and multisystemic involvement may occur in transplant recipients. Supportive care is paramount. The clinical features and viral culture confirm the diagnosis, although tissue samples and quantitative polymerase chain reaction may be required in more severe cases.

Improvement of Mineral and Bone Disorders After Renal Transplantation.

BACKGROUND: Posttransplant mineral and bone diseases are causes of fractures, and their association with cardiovascular events is being studied. METHODS: We analyzed the evolution of biochemical, histological, and imaging parameters pre- and 1 y post-renal transplantation in 69 patients and correlated mineral and bone findings with coronary calcifications. At inclusion and after 12 mo, clinical data and echocardiographic findings were recorded, and laboratory evaluations, radiography of the pelvis and hands, and bone biopsy were performed. Noncontrast cardiac computed tomography was performed during the second evaluation. RESULTS: Serum levels of fibroblast growth factor 23 and sclerostin decreased in all patients, parathyroid hormone levels decreased in 89.8% of patients, bone alkaline phosphatase levels decreased in 68.1% of patients, and alpha-Klotho levels increased in 65.2% of patients. More than half of the patients presented with renal osteodystrophy at both biopsies, but histological findings improved: a significant transition from high to normal or low turnover and no significant differences in volume, mineralization defect, or cortical porosity at the 2 evaluations. Alpha-Klotho, sclerostin, and bone alkaline phosphatase shifts affect bone changes. Neither echocardiographic findings nor vascular calcification scores differed between the 2 points. Both the pretransplant period (dialysis vintage, sclerostin, and low bone volume at baseline) and the maintenance of abnormalities in the posttransplant period (high turnover posttransplant) were the most reliable predictors of the severity of the coronary calcification percentile. CONCLUSIONS: Renal transplantation improved bone and mineral abnormalities. The pretransplant period determines the severity of calcification.

Intraocular implants loaded with A3R agonist rescue retinal ganglion cells from ischemic damage.

Retinal ganglion cell (RGC) loss underlies several conditions which give rise to significant visual compromise, including glaucoma and ischaemic optic neuropathies. Neuroprotection of RGCs is a clinical well-defined unmet need in these diseases, and adenosine A3 receptor (A3R) activation emerges as a therapeutic pharmacological approach to protect RGCs. A porous biodegradable intraocular implant loaded with 2-Cl-IB-MECA (selective A3R agonist) was used as a strategy to protect RGCs. Drug-loaded PCL implants released 2-Cl-IB-MECA for an extended period and the released 2-Cl-IB-MECA limited glutamate-evoked calcium (Ca2+) rise in RGCs. Retinal thinning due to transient ischemia was not prevented by 2-Cl-IB-MECA-PCL implant. However, 2-Cl-IB-MECA-PCL implants decreased retinal cell death, promoted the survival of RGCs, preserved optic nerve structure and anterograde axonal transport. We further demonstrated that 2-Cl-IB-MECA-loaded PCL implants were able to enhance RGC function that was compromised by transient ischemia. Taking into consideration the beneficial effects afforded by 2-Cl-IB-MECA released from the PCL implant, this can be envisaged a good therapeutic strategy to protect RGCs.

The Role of Bone Volume, FGF23 and Sclerostin in Calcifications and Mortality; a Cohort Study in CKD Stage 5 Patients.

Chronic kidney disease-mineral and bone disorder has been associated with increasing morbid-mortality. The aim of this study was to determine the prevalence and phenotype of bone disease before transplantation and to correlate FGF23 and sclerostin levels with bone histomorphometry, and study possible associations between FGF23, sclerostin, and bone histomorphometry with cardiovascular disease and mortality. We performed a cross-sectional cohort study of a sample of 84 patients submitted to renal transplant, which were prospectively followed for 12 months. Demographic, clinical, and echocardiographic data were collected, laboratory evaluation, bone biopsy, and X-ray of the pelvis and hands were performed. Patient and graft survival were recorded. We diagnosed low bone turnover in 16 patients (19.5%); high bone turnover in 22 patients (26.8%); osteomalacia in 1 patient (1.2%), and mixed renal osteodystrophy in 3 patients (3.7%). At the end of 12 months, 5 patients had graft failure (5.9%), 4 had a cardiovascular event (4.8%), and 4 died. Age was associated with low remodeling disease, whereas high BALP and phosphorus and low sclerostin with high turnover disease. Sclerostin was a risk factor for isolated low bone volume. High BALP, low phosphorus, and low FGF23 were risk factors for abnormal mineralization. FGF23 appears as an independent factor for severity of vascular calcifications and for cardiovascular events, whereas the presence of valve calcifications was associated with low volume and with turnover deviations. Sclerostin was associated a higher HR for death. Sclerostin and FGF23 seemed to provide higher cardiovascular risk, as well as low bone volume, which associated with extra-osseous calcifications.

Combined lung-kidney transplantation: First case in Portugal.

A significant dysfunction of another organ is usually considered an absolute contraindication for lung transplantation, unless multiorgan transplantation is indicated and practical, as is the case of combined lung-kidney transplantation. Few cases of combined lung-kidney transplantation have been described in the literature; however, it is known that, in certain cases, it is the only way to offer an opportunity to selected patients with renal and lung dysfunction. The authors are not aware of any previously published case of a patient receiving both extracorporeal membrane oxygenation and continuous venovenous hemodiafiltration as a bridge for combined kidney-lung transplantation. The authors present the first case of combined lung-kidney transplantation performed in Portugal.

Bone densitometry versus bone histomorphometry in renal transplanted patients: a cross-sectional study.

Bone loss leads to increase risk of fractures in renal transplantation. The aim of this study was to analyse the relationship between bone densitometry (DXA) findings, bone histomorphometry and bone-related molecules 1-year after renal transplantation. We performed a cross-sectional study of de novo renal transplanted patients that agreed to perform a bone biopsy and a DXA examination 1 year after transplantation. All patients underwent a laboratory evaluation, bone biopsy, DXA examination and cardiac CT 1 year after transplantation. 67 patients were included, 16 had a normal examination, and 18 patients were classified as having osteoporosis by DXA. Correlations between bone mineral density and T-scores of total femur and femoral neck were the ones that best correlated with bone volume assessed by a bone biopsy. The sensitivity of DXA for osteoporosis diagnosis was 47.0%, and the specificity was 81.2%. The positive predictive value was 50.0%, and the negative predictive value (NPV) was 80.0%. DXA parameters also correlated with klotho and sclerostin serum levels. In this population, a normal examination excluded the presence of osteoporosis, helping in identifying patients that would not benefit from therapy. Overall, densitometry in total femur and femoral neck correlated well with bone volume measured by bone biopsy.

Activation of Adenosine A3 Receptor Inhibits Microglia Reactivity Elicited by Elevated Pressure.

Glaucoma is a progressive chronic retinal degenerative disease and a leading cause of global irreversible blindness, characterized by optic nerve damage and retinal ganglion cell (RGC) death. Elevated intraocular pressure (IOP) is a main risk factor of glaucoma. Neuroinflammation plays an important role in glaucoma. We have been demonstrating that elevated pressure triggers microglia reactivity that contribute to the loss of RGCs. Adenosine, acting on adenosine receptors, is a crucial modulator of microglia phenotype. Microglia express all adenosine receptors. Previously, we demonstrated that the activation of adenosine A3 receptor (A3R) affords protection to the retina, including RGCs, unveiling the possibility for a new strategy for glaucoma treatment. Since microglial cells express A3R, we now studied the ability of a selective A3R agonist (2-Cl-IB-MECA) in controlling microglia reactivity induced by elevated hydrostatic pressure (EHP), used to mimic elevated IOP. The activation of A3R reduced EHP-induced inducible nitric oxide synthase (iNOS) expression, microglia migration and phagocytosis in BV-2 cells. In retinal microglia, proliferation and phagocytosis elicited by EHP were also decreased by A3R activation. This work demonstrates that 2-Cl-IB-MECA, the selective agonist of A3R, is able to hinder microglia reactivity, suggesting that A3R agonists could afford protection against glaucomatous degeneration through the control of neuroinflammation.

Activation of adenosine A3 receptor protects retinal ganglion cells from degeneration induced by ocular hypertension.

Glaucoma is a progressive chronic retinal degenerative disease and a leading cause of global irreversible blindness. This disease is characterized by optic nerve damage and retinal ganglion cell (RGC) death. The current treatments available target the lowering of intraocular pressure (IOP), the main risk factor for disease onset and development. However, in some patients, vision loss progresses despite successful IOP control, indicating that new and effective treatments are needed, such as those targeting the neuroprotection of RGCs. Adenosine A3 receptor (A3R) activation confers protection to RGCs following an excitotoxic stimulus. In this work, we investigated whether the activation of A3R could also afford protection to RGCs in the laser-induced ocular hypertension (OHT) model, a well-characterized animal model of glaucoma. The intravitreal injection of 2-Cl-IB-MECA, a selective A3R agonist, abolished the alterations induced by OHT in the negative and positive components of scotopic threshold response (STR) without changing a- and b-wave amplitudes both in scotopic and photopic conditions. Moreover, the treatment of OHT eyes with the A3R agonist promoted the survival of RGCs, attenuated the impairment in retrograde axonal transport, and improved the structure of the optic nerve. Taking into consideration the beneficial effects afforded by 2-Cl-IB-MECA, we can envisage that A3R activation can be considered a good therapeutic strategy to protect RGCs from glaucomatous damage.

Keep an eye on adenosine: Its role in retinal inflammation.

Adenosine is an endogenous purine nucleoside ubiquitously distributed throughout the body that interacts with G protein-coupled receptors, classified in four subtypes: A1R, A2AR, A2BR and A3R. Among the plethora of functions of adenosine, it has been increasingly recognized as a key mediator of the immune response. Neuroinflammation is a feature of chronic neurodegenerative diseases and contributes to the pathophysiology of several retinal degenerative diseases. Animal models of retinal diseases are helping to elucidate the regulatory roles of adenosine receptors in the development and progression of those diseases. Mounting evidence demonstrates that the adenosinergic system is altered in the retina during pathological conditions, compromising retinal physiology. This review focuses on the roles played by adenosine and the elements of the adenosinergic system (receptors, enzymes, transporters) in the neuroinflammatory processes occurring in the retina. An improved understanding of the molecular and cellular mechanisms of the signalling pathways mediated by adenosine underlying the onset and progression of retinal diseases will pave the way towards the identification of new therapeutic approaches.

Intravitreal injection of adenosine A2A receptor antagonist reduces neuroinflammation, vascular leakage and cell death in the retina of diabetic mice.

Diabetic retinopathy is a major complication of diabetes mellitus and a leading cause of blindness. The pathogenesis of diabetic retinopathy is accompanied by chronic low-grade inflammation. Evidence shows that the blockade of adenosine A2A receptors (A2AR) affords protection to the retina through the control of microglia-mediated neuroinflammation. Herein, we investigated the therapeutic potential of an antagonist of A2AR in a model of diabetic retinopathy. Type 1 diabetes was induced in 4-5 months old C57BL/6 J mice with a single intraperitoneal injection streptozotocin. Animals were treated one month after the onset of diabetes. The A2AR antagonist was delivered by intravitreal injection once a week for 4 weeks. Microglia reactivity and inflammatory mediators were increased in the retinas of diabetic animals. The treatment with the A2AR antagonist was able to control microglial reactivity and halt neuroinflammation. Furthermore, the A2AR antagonist rescued retinal vascular leakage, attenuated alterations in retinal thickness, decreased retinal cell death and the loss of retinal ganglion cells induced by diabetes. These results demonstrate that intravitreal injection of the A2AR antagonist controls inflammation, affords protection against cell loss and reduces vascular leakage associated with diabetes, which could be envisaged as a therapeutic approach for the early complications of diabetes in the retina.

An Atypical Presentation of Thrombotic Microangiopathy After Lung Transplant: A Case Report.

Thrombotic microangiopathy (TMA) is a pathologic condition characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ injury due to microvascular endothelial lesions and thrombosis. It occurs in a variety of diseases and, unless recognized and treated, leads to severe morbidity and mortality. We present the case of a 48-year-old woman who underwent lung transplantation, initially under tacrolimus, mycophenolate mofetil (MMF), and prednisolone. Several complications emerged in the following months, including abdominal aortic and left renal artery thrombosis and cutaneous infections, although her renal function remained normal. Six months after transplant, her renal function began to deteriorate, which was assumed to be due to elevated tacrolimus levels and doses were adjusted. Due to leukopenia, MMF was changed to everolimus. One year after, she was admitted with fatigue, anemia, and renal dysfunction. Complementary exams revealed only iron deficiency, leukopenia, normal platelets, and elevated lactate dehydrogenase; her renal ultrasound was normal. A renal biopsy was performed and thrombotic microangiopathy was subsequently identified as the main cause of the renal dysfunction. Tacrolimus was therefore discontinued and MMF restarted with slow improvement of renal function. Only when everolimus was stopped did the patient's renal function show incremental improvement. TMA may be a serious complication after lung transplantation and the risk is higher when a combination of tacrolimus and everolimus is used. Renal biopsy findings are essential to confirm the final diagnosis of TMA, allowing for a change in immunosuppression to prevent permanent and severe renal damage.

Blockade of microglial adenosine A2A receptor suppresses elevated pressure-induced inflammation, oxidative stress, and cell death in retinal cells.

Glaucoma is a retinal degenerative disease characterized by the loss of retinal ganglion cells and damage of the optic nerve. Recently, we demonstrated that antagonists of adenosine A2A receptor (A2A R) control retinal inflammation and afford protection to rat retinal cells in glaucoma models. However, the precise contribution of microglia to retinal injury was not addressed, as well as the effect of A2A R blockade directly in microglia. Here we show that blocking microglial A2A R prevents microglial cell response to elevated pressure and it is sufficient to protect retinal cells from elevated pressure-induced death. The A2A R antagonist SCH 58261 or the knockdown of A2A R expression with siRNA in microglial cells prevented the increase in microglia response to elevated hydrostatic pressure. Furthermore, in retinal neural cell cultures, the A2A R antagonist decreased microglia proliferation, as well as the expression and release of pro-inflammatory mediators. Microglia ablation prevented neural cell death triggered by elevated pressure. The A2A R blockade recapitulated the effects of microglia depletion, suggesting that blocking A2A R in microglia is able to control neurodegeneration in glaucoma-like conditions. Importantly, in human organotypic retinal cultures, A2A R blockade prevented the increase in reactive oxygen species and the morphological alterations in microglia triggered by elevated pressure. These findings place microglia as the main contributors for retinal cell death during elevated pressure and identify microglial A2A R as a therapeutic target to control retinal neuroinflammation and prevent neural apoptosis elicited by elevated pressure.

Are high flow arteriovenous accesses associated with worse haemodialysis? / Acessos arteriovenosos de alto débito estão associados a pior hemodiálise?

ABSTRACT Introduction: An arteriovenous (AV) access flow (Qa) of 400 mL/min is usually sufficient for an effective hemodialysis (HD), but some accesses continue developing and become high flow accesses (HFA). Some authors postulated that an HFA might shift a significant portion of dialyzed blood from the cardiac output, which could decrease HD efficiency and lead to volume overload. Objective: The aim of our study was to evaluate if HFA is associated with reduced HD efficiency and/or volume overload in prevalent HD patients. Methods: We performed a 1-year retrospective study and assessed HD efficiency by the percentage of sessions in which the Kt/V > 1.4 and volume overload by bioimpedance spectroscopy. Results: The study included 304 prevalent HD patients with a mean age of 67.5 years; 62.5% were males, 36.2% were diabetics, with a median HD vintage of 48 months. Sixteen percent of the patients had a HFA (defined as Qa > 2 L/min). In multivariate analysis, patients with HFA presented higher risk of volume overload (OR = 2.67, 95%CI = 1.06-6.71) and severe volume overload (OR = 4.06, 95%CI = 1.01-16.39) and attained dry weight less frequently (OR = 0.37, 95%CI = 0.14-0.94). However, HFA was not associated with lower Kt/V. Conclusion: Our results suggest that patients with HFA have higher risk of volume overload. However, contrarily to what has been postulated, HFA was not associated with less efficient dialysis, measured by Kt/V. Randomized controlled trials are needed to clarify these questions.

RESUMO Introdução: Um débito de sangue de acesso arteriovenoso (AV) (Qa) de 400 mL/min é geralmente suficiente para uma hemodiálise (HD) eficaz, mas alguns acessos continuam se desenvolvendo e se tornam acessos de alto débito (AAD). Alguns autores postularam que um AAD poderia desviar uma porção significativa do sangue dialisado do débito cardíaco, o que poderia diminuir a eficiência da HD e levar à sobrecarga de volume. Objetivo: O objetivo do nosso estudo foi avaliar se o AAD está associado à redução da eficiência da HD e/ou à sobrecarga de volume em pacientes prevalentes em HD. Métodos: Foi realizado um estudo retrospectivo de 1 ano, e avaliada a eficiência da HD pela porcentagem de sessões em que o Kt/V > 1,4 e a sobrecarga de volume avaliada pela bioimpedância. Resultados: O estudo incluiu 304 pacientes prevalentes em HD, com média de idade de 67,5 anos; 62,5% eram do sexo masculino; 36,2% eram diabéticos, com uma mediana de tempo em HD de 48 meses. Dezesseis por cento dos pacientes apresentavam AAD (definida como Qa > 2 L/min). Na análise multivariada, os pacientes com AAD apresentaram maior risco de sobrecarga de volume (OR = 2,67; IC95% = 1,06-6,71) e sobrecarga severa de volume (OR = 4,06; IC95% = 1,01-16,39) e atingiram o peso seco com menor frequência (OR = 0,37, IC 95% = 0,14-0,94). No entanto, o AAD não foi associado uma menor razão Kt/V. Conclusão: Nossos resultados sugerem que pacientes com AAD apresentam maior risco de sobrecarga de volume. No entanto, ao contrário do que foi postulado, o AAD não foi associado à diálise menos eficiente, medida pelo Kt/V. Ensaios clínicos randomizados são necessários para esclarecer essas questões.

Elevated Pressure Changes the Purinergic System of Microglial Cells.

Glaucoma is the second cause of blindness worldwide and is characterized by the degeneration of retinal ganglion cells (RGCs) and optic nerve atrophy. Increased microglia reactivity is an early event in glaucoma that may precede the loss of RGCs, suggesting that microglia and neuroinflammation are involved in the pathophysiology of this disease. Although global changes of the purinergic system have been reported in experimental and human glaucoma, it is not known if this is due to alterations of the purinergic system of microglial cells, the resident immune cells of the central nervous system. We now studied if elevated hydrostatic pressure (EHP), mimicking ocular hypertension, changed the extracellular levels of ATP and adenosine and the expression, density and activity of enzymes, transporters and receptors defining the purinergic system. The exposure of the murine microglial BV-2 cell line to EHP increased the extracellular levels of ATP and adenosine, increased the density of ecto-nucleoside triphosphate diphosphohydrolase 1 (E-NTPDase1, CD39) and decreased the density of the equilibrative nucleotide transporter 2 as well as the activity of adenosine deaminase. The expression of adenosine A1 receptor also decreased, but the adenosine A3 receptor was not affected. Notably, ATP and adenosine selectively control migration rather than phagocytosis, both bolstered by EHP. The results show that the purinergic system is altered in microglia in conditions of elevated pressure. Understanding the impact of elevated pressure on the purinergic system will help to unravel the mechanisms underlying inflammation and neurodegeneration associated with glaucoma.

Optimizing the use of darbepoetin-α with a split strategy: A concept change
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As erythropoiesis is a continuous process, we hypothesized that a new approach with smaller doses of darbepoetin-α administered more regularly could result in fewer variations of its serum levels and be more effective. In a prevalent hemodialysis population, we evaluated the effects of the darbepoetin splitting in "mini-doses". A 34-month prospective study was performed in a cohort of 110 patients, with a mean age of 66.6 ± 14.2 years, median dialysis vintage of 63.6 months (IQ range: 27 - 86), 46.4% (n = 51) male gender, 36.4% (n = 40) diabetics. In the first 12 months of the study, the usual dose regime for darbepoetin (weekly, every other week, or monthly) was unchanged. In the following 22 months, darbepoetin doses were divided into multiples of 10 µg and administered in the maximum possible number of hemodialysis (HD) sessions. Paired Student's t or Wilcoxon matched-pairs analyses were performed. After darbepoetin splitting, we verified a decrease in its consumption (1.9 ± 1.7 to 1.4 ± 1.6 µg/kg, p < 0.0001) and in the erythropoietin resistance index (8.6 to 6.7 IU/kg/week, p = 0.0001), with stable hemoglobin levels (11.4 ± 0.7 to 11.3 ± 0.6 g/dL, p = 0.02). We also observed an increase in ferritin levels (490 ± 138.2 to 560.7 ± 149.3 µg/L, p < 0.0001) and C-reactive protein (CRP) levels, with no changes in iron doses (2.2 - 3.2 mg/kg, p = 0.24). From these results, we conclude that the splitting of darbepoetin in "mini-doses" is highly effective, potentially allowing a significant decrease in the costs of anemia treatment. Larger and randomized studies are needed to prove the cost-benefit of this new strategy.
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Treatment with A2A receptor antagonist KW6002 and caffeine intake regulate microglia reactivity and protect retina against transient ischemic damage.

Transient retinal ischemia is a major complication of retinal degenerative diseases and contributes to visual impairment and blindness. Evidences indicate that microglia-mediated neuroinflammation has a key role in the neurodegenerative process, prompting the hypothesis that the control of microglia reactivity may afford neuroprotection to the retina against the damage induced by ischemia-reperfusion (I-R). The available therapeutic strategies for retinal degenerative diseases have limited potential, but the blockade of adenosine A2A receptor (A2AR) emerges as candidate strategy. Therefore, we evaluated the therapeutic potential of a selective A2AR antagonist (KW6002) against the damage elicited by I-R. The administration of KW6002 after I-R injury reduced microglia reactivity and inflammatory response and afforded protection to the retina. Moreover, we tested the ability of caffeine, an adenosine receptor antagonist, in mediating protection to the retina in the I-R injury model. We demonstrated that caffeine administration dually regulated microglia reactivity and cell death in the transient retinal ischemic model, depending on the reperfusion time. At 24 h of reperfusion, caffeine increased microglial reactivity, inflammatory response and cell death elicited by I-R. However, at 7 days of reperfusion, caffeine administration decreased microglia reactivity and reduced the levels of proinflammatory cytokines and cell death. Together, these results provide a novel evidence for the use of adenosine A2AR antagonists as potential therapy for retinal ischemic diseases and demonstrate the effect of caffeine on the regulation of microglia-mediated neuroinflammation in the transient ischemic model.

Cholecalciferol supplementation in hemodialysis patients: effects on mineral metabolism, inflammation, and cardiac dimension parameters.

BACKGROUND AND OBJECTIVES: Vitamin D deficiency is highly prevalent in chronic kidney disease. The aim of this study was to evaluate the effects of oral cholecalciferol supplementation on mineral metabolism, inflammation, and cardiac dimension parameters in long-term hemodialysis (HD) patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This 1-year prospective study included 158 HD patients. Serum levels of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], intact parathyroid hormone, and plasma brain natriuretic peptide as well as circulating bone metabolism and inflammation parameters were measured before and after supplementation. Baseline 25(OH)D and 1,25(OH)(2)D levels were measured twice (end of winter and of summer, respectively). Therapy with paricalcitol, sevelamer, and darbepoietin was evaluated. RESULTS: There was an increase in serum 25(OH)D and 1,25(OH)(2)D levels after supplementation. Conversely, serum calcium, phosphorus, and intact parathyroid hormone were decreased. There was a reduction in the dosage and in the number of patients who were treated with paricalcitol and sevelamer. Darbepoietin use was also reduced, with no modification of hemoglobin values. Serum albumin increased and C-reactive protein decreased during the study. Brain natriuretic peptide levels and left ventricular mass index were significantly reduced at the end of the supplementation. CONCLUSIONS: Oral cholecalciferol supplementation in HD patients seems to be an easy and cost-effective therapeutic measure. It allows reduction of vitamin D deficiency, better control of mineral metabolism with less use of active vitamin D, attenuation of inflammation, reduced dosing of erythropoiesis-stimulating agents, and possibly improvement of cardiac dysfunction.

25-Hydroxyvitamin D3, arterial calcifications and cardiovascular risk markers in haemodialysis patients.

BACKGROUND: Decreased vitamin D serum levels have been recently related to arterial stiffening and vascular calcifications in haemodialysis (HD) patients, but the pathophysiology of this association is not yet clear. The aim of this study was to evaluate the relationship between vascular calcifications, cardiovascular risk factors [including brain natriuretic peptide (BNP), pulse pressure (PP) and left ventricular mass index] and 25-hydroxyvitamin D3 (25(OH)D3) and 1,25-dihydroxyvitamin D3 [1,25(OH)(2)D3] serum levels. METHODS: We performed a cross-sectional study with 223 prevalent HD patients, 48% females, 27% diabetics, with the mean age of 62.7 +/- 15.3 years and the mean HD time of 42.9 +/- 39.3 months. Forty-seven percent of the patients were taking active forms of vitamin D. RESULTS: Serum levels of [25(OH)D3] were low (21.6 +/- 12.2 ng/mL) and negatively correlated with age (r = -0.31, P < 0.001), diabetes mellitus (DM) (r = -0.20, P = 0.004), C-reactive protein (r = -0.25, P < 0.001), log(10) BNP (r = -0.22, P = 0.002), PP > 65 mmHg (r = -0.21, P = 0.003) and vascular calcifications (r = -0.26, P < 0.001). Levels of [25(OH)D3] were positively correlated with [1,25(OH)(2)D3] (r = 0.25, P < 0.001) and albumin (r = 0.23, P = 0.001). On multivariate analysis, levels of [25(OH)D3] were independently associated with DM (P < 0.001), lower albumin levels (P = 0.003), higher BNP values (P = 0.005), PP > 65 mmHg (P = 0.006) and a higher vascular calcification score (>or= 3) (P = 0.002). CONCLUSIONS: These results suggest that lower levels of [25(OH)D3] are a cardiovascular risk marker in HD patients, since they are strongly associated with higher BNP levels, increased PP and with the presence of vascular calcifications. The exact role of [25(OH)D3] deficiency on cardiovascular morbi-mortality needs to be clarified in large randomized controlled trials.