The presence of a CD4+ CD25high CD45RO+ CD127high T-cell population correlates with the clinical status of kidney transplant recipients

Background: Recent data have suggested that a population of CD4+ CD25high T cells, phenotypically characterized by the expression of CD45RO and CD127, is significantly expanded in stable liver and kidney transplant recipients and represents alloreactive T cells. We analyzed this putative new alloreactive cellular marker in various groups of kidney transplant recipients. Patients and methods: Flow cytometry was used to analyze the expression of CD25, CD45RO and CD127 on peripheral CD4+ T cells. Of 73 kidney recipients, 59 had a stable graft function under standard immunosuppressive therapy (IS), 5 had biopsy-proven chronic humoral rejection (CHR), 8 were stable under minimal IS and one was an operationally "tolerant" patient who had discontinued IS for more than 3 years. Sixty-six healthy subjects (HS) were studied as controls. Results: Overall, the alloreactive T cell population was found to be significantly increased in the 73 kidney recipients (mean ± SE: 15.03 ± 1.04% of CD4+ CD25high T cells) compared to HS (5.93 ± 0.39%) (p <0.001). In the 5 patients with CHR, this population was highly expanded (31.33 ± 4.16%), whereas it was comparable to HS in the 8 stable recipients receiving minimal IS (6.12 ± 0.86%), in 4 patients who had been switched to sirolimus (4.21 ± 0.53%) as well as in the unique "tolerant" recipient (4.69%). Intermediate levels (15.84 ± 0.93%) were found in the 55 recipients with stable graft function on standard CNI-based IS. Regulatory T cells, defined as CD4+ CD25high FoxP3+ CD127low, were found to be significantly reduced in all recipients except in those with minimal or no IS, and this reduction was particularly striking in recipients with CHR. Conclusion: After kidney transplantation, an alloreactive T cell population was found to be significantly expanded and it correlates with the clinical status of the recipients. Interestingly, in stable patients with minimal (or no) IS as well as in patients on sirolimus, alloreactive T cells were comparable the healthy controls. Measuring circulating CD4+ CD25high CD45RO+ CD127high T cells may become a useful monitoring tool after transplantation.

Combined islet-lung transplantation in a cystic fibrosis patient.

The prevalence of insulin-dependent diabetes mellitus (IDDM) in cystic fibrosis patients ranges from 2 to 8% and glucose intolerance up to 15%. In recent years, lung transplantation has helped to prolong life expectancy of cystic fibrosis patients and represents 10 to 30% of all indications for lung transplantation. The postoperative need for immunosuppressive therapy using diabetogenic agents has decompensatory effects on glucose regulation and will probably increase the number of insulin-dependent cystic fibrosis patients. We report the case of an insulin-dependent cystic fibrosis patient transplanted with a combined islet-lung allograft. The pre-transplantation C-peptide level was below 0.04 nmol/l and preoperative insulin requirement was some 100 U per day. A sequential bipulmonary lung transplantation was performed and, using the pancreas of the same donor, we isolated and purified the islets of Langerhans by a modified automated method. We obtained 232,200 islets equivalent, which were injected into the liver by portal embolization. The postoperative course was uncomplicated, the insulin requirement decreased to 50% of the preoperative need and the C-peptide value increased to normal values and remained with the normal range during a follow-up period of 15 months. In conclusion, we believe that, besides type I diabetic patients, insulin-dependent cystic fibrosis patients with a negative C-peptide value could also be good candidates for combined islet-lung allotransplantation.

Meningococcal disease in a kidney transplant recipient with mannose-binding lectin (MBL) deficiency

Background: There is an increasing amount of data associating MBL deficiency with a higher susceptibility to meningococca[ disease. In addition, meningococca[ disease has been reported in patients with various immunosuppressive conditions. However, to our knowledge, only three cases of meningococca[ disease have been reported in solid organ recipients (SOT). Methods & Results: A 32 year-old male patient underwent cadaveric kidney transplantation for endstage renal disease of unknown origin. On day 71 post-transplantation he developed fever (39.6°C), shaking chilis, and tachycardia without hypotension. At this time, immunosuppression consisted of tacro[imus, prednisone 10mg daily and mycopheno[ ate mofeti[ 2 g daily. Physical examination on admission was normal, except for two small petechia[ lesions on the forearm. No meningeal signs were present. Three sets of blood cultures grew Neisseria meningitidis group C susceptible to ceftriaxone (MIC=0.003mg/[). Antibiotic therapy consisted in intravenous ceftriaxone 2 g per day for a total duration of 7 days. Serum immunog[obu[in levels, C3, C4 and CHS0 were normal However, using a method to screen for the functional activity of a[[ three pathways of complement (Wies[ab, Lund, Sweden), no activation via the MBL pathway could be detected (0%). A subsequent quantification of MBL pathway components revealed normal levels of MASP 2 but undetectab[e amounts of MBL (below 10 ng/m[, normal range: >500 ng/m[). Conclusion: Since the exact incidence and the possible relationship between meningococca[ disease and organ transplantation is not we[[ understood, we strongly encourage transplantation centers to report additional cases. The potential clinical usefu[ ness of screening SOT candidates for MBL deficiency in relation to infectious complications after transplantation remains to be determined.

Characterization of functional role of α-ketoglutarate receptor in the kidney : role of the intrinsic circadian timing system in renin expressing cells

Le rein joue un rôle essential dans le maintien de l'homéostasie des fluides extracellulaires (FEC) et la pression artérielle. L'objectif de notre groupe est d'identifier de nouveaux mécanismes impliqués dans le contrôle de l'homéostasie des FEC et de la pression artérielle par le rein. Projet 1) Caractérisation du rôle fonctionnel du récepteur à l'a-cétogluatarate Oxgrl dans le rein Oxgrl est le récepteur spécifique de l'a-cétogluatarate, une moléule intermédiaire du cycle de l'acide citrique, filtrée par le rein et réabsorbée ou secrétée au niveau des tubules proximaux. Le rôle fonctionnel de ces deux récepteurs reste inconnu. Nos résultats montrent qu'Oxgrl est localisé au niveau des cellules intercalaires du tube collecteur (CCD). Des souris (Oxgrr/_) montrent une diminution du pH urinaire ,une augmentation de la concentration de l'acide urinaire titrable et une augmentation des niveaux d'a-cétoglutarate. Le traitement au Na-bicarbonate provoque une augmentation plus prononcée de l'alcalose métabolique chez les souris Oxgrl"7"' accompagnée d'une augmentation de la concentration de bicarbonate et une diminution du niveau de chlore plasmatique. En parallèle, des études de microperfusion ont montré que a-cétoglutarate stimule la réabsorption éléctroneutre de NaCl dans le CCD des souris de type sauvage mais pas des souris Oxgrl"7". En résumé, ces résultats montrent que l'a-cétoglutarate joue un rôle de molécule messagère du tubule proximal jusqu'au tube collecteur au niveau du rein et qu'Oxgrl pourrait être impliqué dans la régulation de l'échange Cl/bicarbonate et la réabsorption du NaCl dans les cellules intercalées. Projet 2) Rôle du système circadien dans les cellules productrices de rénine. Le système chronologique circadien est un mécanisme moléculaire ubiquitaire qui permet à l'organisme de coordonner ses fonctions principales en fonction du temps géophysique. Comme l'activité de la rénine plasmatique montre une rythmicité circadienne nette chez l'homme et la souris ; dans ce projet, nous avons abordé la question à savoir dans quelle mesure le système circadien est impliqué dans cette variabilité circadienne. Pour cela, le gène Bmall, élément principal de l'horloge moléculaire, a été perturbé dans les cellules granulaires productrices de rénine par le système Cre-LoxP. Nos résultats montrent que les souris Renld- Cre/Bmalllox/lox (cKO) présentent de faibles taux d'ARNm de Reni, altèrent la dynamique d'expression de la protéine rénine, mais il le niveau de concentration plasmatique de la rénine reste le même. Cependant, les souris cKO montrent une réduction significative de la concentration plasmatique de l'aldostérone. Nos analyses de l'urine récupérée dans des intervalles de temps de 24 et 1 heure montrent une augmentation du volume urinaire, une tendance à une hypercalciurie, ainsi qu'une altération de la dynamique d'excrétion urinaire de sodium chez les souris cKO. Plusieurs gènes impliqués dans la production/sécrétion de la rénine et dans le contrôle de la fonction rénale montrent une altération de l'expression circadienne d'ARNm. Par ailleurs, les souris cKO montrent une baisse significative de la pression artérielle. Nos résultats suggèrent que l'horloge intrinsèque des cellules productrices de la rénine joue un rôle important dans le control des FEC et l'homéostasie de la pression artérielle via régulation de la fonction rénale.

Thérapies inhalées dans la mucoviscidose [Inhaled therapies for cystic fibrosis].

Inhaled therapies play a significant role in the management of cystic fibrosis patients. Mucolytic and airway-rehydrating agents improve mucociliary clearance and respiratory functional status. Nebulized antibiotherapy achieve high local concentration, while reducing systemic toxicity. Tolerance to inhaled treatments is good excepting frequent bronchoconstriction which can usually be prevented by prior administration of beta2-mimetics. The majority of treatments are only available in liquid formulations. Thus, nebulization is the most frequently used inhalation mode. Vibrating-mesh nebulizers have significantly reduced inhalation time.

Role of the NALP3 Inflammasome in the Development of Two-Kidney, One Clip Hypertension in Mice

Objective: The NALP3 inflammasome functions as a sensor of danger signals and triggers processing and release of IL-1b. Mutations of NALP3 are responsible for the cryopyrin associated periodic syndromes, a group of autoinflammatory disorders that respond to IL1 inhibition. Genetic studies have also linked NALP3 to hypertension in man, but the mechanism is not understood. The aim of this study is to investigate the role of NAPL3 inflammasome in the development of hypertension in an animal model. Design and Method: Six-week old male WT and NALP3 KO mice were used for generating a two-kidney, one clip (2K1C) renovascular hypertension. A U-shaped stainless steel clip (O^ ¼0.12mm) was placed on left renal artery under anaesthesia. The same surgery without clipping was performed in sham mice. At week 6 and 12 after the clipping, intra-arterial blood pressure (BP) was measured in conscious mice. Blood was collected for plasma renin analysis. Heart and kidney were excised and stored for molecular and morphological examinations. n¼5-6 mice per group. Data are mean_SEM. Results: Mean BP was significantly increased at week 6 and 12 in WT-2K1C mice compared to WT-sham group (MBPweek6: 138_2 vs.124_3 mmHg, p<0.01 and MBPweek12: 141_5 vs.122_3 mmHg, p<0.01) followed with an significant increase in heart weight (HW) and a decrease in clipped kidney weight indices in WT-2K1C mice compared to the WT-sham (HW/ BWweek6: 4.65_0.04 vs. 3.99_0.12 mg/g, p<0.001 and HW/BWweek12: 4.94_0.15 vs. 4.22_0.12 mg/g, p<0.001). Interestingly, NALP3 KO-2K1C mice did not develop hypertension. The MBP of KO-2K1C mice was comparable to the KO-sham (MBPweek6: 122_3 vs. 119_3 mmHg, p>0.05 and MBPweek6: 128_5 vs.122_4 mmHg, p>0.05). There was also no significant change in heart and kidney weight indices between KO- 2K1C and KO-sham mice. Conclusion: The preliminary results suggest that absence of NALP3 protects mice from the development of renin-dependent hypertension. Further molecular and morphological examinations are ongoing for the confirmation and mechanism explanation.

Psychological profile of adolescents with a kidney transplant.

To describe the psychological profile of renal transplant adolescents compared to healthy peers and to adolescents with CKD, three groups of adolescents aged 12-18 yr were selected: TX, CX, and adolescents with CKD. Psychiatric symptoms and disorders were evaluated through direct interviews (K-SADS-PL) and self-report questionnaires (YSR and CBCL). Forty TX (14 LRD and 26 DD transplant recipients), 40 CX and 20 CKD were included. Twelve of 40 (30%) TX, three of 20 (15%) CKD, and three of 40 (7.5%) CX had a history of learning difficulties (p = 0.03). Compared to CX, TX had lower total YSR competencies score (p = 0.028) and lower total CBCL competencies score (p = 0.003). Twenty-six of 40 (65%) TX, 12 of 20 (60%) CKD and 15 of 40 (37.5%) CX (p = 0.038) met DSM-IV diagnostic criteria for lifetime psychiatric disorder, with rates of depressive disorder of 35% among TX and CKD compared to 15.2% among CX (p = 0.043). Eight of 40 (20%) TX had a history of simple phobia. Nine of 40 (22.5%) TX met diagnostic criteria for ADHD as compared to one of 20 (5%) CKD and three of 40 (7.5%) CX. In the TX group, we found no significant differences in educational and psychiatric variables between LRD and DD. In conclusion, we found a high prevalence of psychiatric morbidity (depression, phobia, ADHD), educational impairment and social competence problems in the TX group. CKD scored in between TX and CX on most measures.

Inducible kidney-specific Sgk1 knockout mice show a salt-losing phenotype.

The expression of the serum- and glucocorticoid-regulated kinase 1 (Sgk1) is induced by mineralocorticoids and, in turn, upregulates the renal epithelial Na(+) channel (ENaC). Total inactivation of Sgk1 has been associated with transient urinary Na(+) wasting with a low-Na(+) diet, while the aldosterone-mediated ENaC channel activation was unchanged in the collecting duct. Since Sgk1 is ubiquitously expressed, we aimed to study the role of renal Sgk1 and generated an inducible kidney-specific knockout (KO) mouse. We took advantage of the previously described TetOn/CreLoxP system, in which rtTA is under the control of the Pax8 promotor, allowing inducible inactivation of the floxed Sgk1 allele in the renal tubules (Sgk1fl/fl/Pax8/LC1 mice). We found that under a standard Na(+) diet, renal water and Na(+)/K(+) excretion had a tendency to be higher in doxycycline-treated Sgk1 KO mice compared with control mice. The impaired ability of Sgk1 KO mice to retain Na(+) increased significantly with a low-salt diet despite higher plasma aldosterone levels. On a low-Na(+) diet, the Sgk1 KO mice were also hyperkaliuric and lost body weight. This phenotype was accompanied by a decrease in systolic and diastolic blood pressure. At the protein level, we observed a reduction in phosphorylation of the ubiquitin protein-ligase Nedd4-2 and a decrease in the expression of the Na(+)-Cl(-)-cotransporter (NCC) and to a lesser extent of ENaC.

Polykystose hépatorénale: développements récents [Recent insights into polycystic kidney disease]

Autosomal dominant polycystic kidney disease is one of the most prevalent genetic diseases and every general practitioner may have to counsel these patients. The follow-up of the patients carrying the trait has changed substantially lately and new treatments have been developed and are close to get approval. We review here the new ultrasound diagnostic criteria, the place of the renal volumetry by MRI in the follow-up, the place of the genetic molecular diagnosis and we discuss the pathogenesis and the future treatment that are in phase III clinical studies and will soon change completely the outcome of the disease.

Exacerbations aiguës au cours de la fibrose pulmonaire idiopathique [Acute exacerbations of idiopathic pulmonary fibrosis].

Although generally considered as a slowly evolving disease, idiopathic pulmonary fibrosis (IPF) is also characterized by episods of rapid deterioration with worsening of dyspnea and hypoxemia, and new ground glass opacities at imaging. These events called "acute exacerbations" (AE) are responsible for half of all deaths in IPF. Pathophysiologic mechanisms of AE are poorly understood. The effectiveness of corticosteroids and immunosuppressive agents appears limited. The mortality of AE is 60-70%. Preventing or controlling AE could improve the overall prognosis of IPF. AE also exist in other interstitial lung diseases.

Transgenic mice and their impact on kidney research.

The kidney is a key organ in the maintenance of ion and fluid homeostasis and specific transport systems localized along the nephron guarantee this function. Due to its large functional heterogeneity, experiments on the whole organ level cannot be easily performed, and thus more refined tools are needed, like for example the development of specific recombination systems to gain knowledge on the physiological role of single proteins implicated in ion transport. This review introduces the transgenic technology developed over the past decades, and then focuses on recent strategies for generating kidney-specific gene targeting, over-expression, and gene ablation in mice, that will help to understand the physiological role of proteins implicated in salt and water balance in the kidney.

Calcifications vasculaires et déficit en vitamine K: un facteur de risque modifiable dans l'insuffisance rénale chronique [Vascular calcifications and vitamin K deficiency: a modifiable risk factor in chronic kidney disease].

The mechanisms of vascular calcifications in chronic renal failure are complex. Apart for clotting factors, vitamin K-dependent proteins include matrix Gla protein. Glutamic acid residues in matrix Gla protein are carboxylated by vitamin K-dependent gamma-carboxylase, which enables it to inhibit calcification. The purpose of this review is to discuss available evidence implicating vitamin K as a modifiable risk factor in the pathogenesis of vascular calcification in renal diseases.

Treatment of mediastinal fibrosis with mycophenolate mofetil.

We present the case of a 67-year-old male patient with mediastinal and retroperitoneal fibrosis. In Europe, this is a rare disease. Treatment was established to prevent complications due to strictures or compressions. Because of his diabetes, a therapy of low-dose prednisone combined with mycophenolate mofetil, known as steroid sparing agent, was applied. As a result, the radiological follow-up showed a marked decrease in the mediastinal and retroperitoneal masses.

cAMP-dependent chloride secretion mediates tubule enlargement and cyst formation by cultured mammalian collecting duct cells.

Polycystic kidney diseases result from disruption of the genetically defined program that controls the size and geometry of renal tubules. Cysts which frequently arise from the collecting duct (CD) result from cell proliferation and fluid secretion. From mCCD(cl1) cells, a differentiated mouse CD cell line, we isolated a clonal subpopulation (mCCD-N21) that retains morphogenetic capacity. When grown in three-dimensional gels, mCCD-N21 cells formed highly organized tubular structures consisting of a palisade of polarized epithelial cells surrounding a cylindrical lumen. Subsequent addition of cAMP-elevating agents (forskolin or cholera toxin) or of membrane-permeable cAMP analogs (CPT-cAMP) resulted in rapid and progressive dilatation of existing tubules, leading to the formation of cystlike structures. When grown on filters, mCCD-N21 cells exhibited a high transepithelial resistance as well as aldosterone- and/or vasopressin-induced amiloride-sensitive and -insensitive current. The latter was in part inhibited by Na(+)-K(+)-2Cl(-) cotransporter (bumetanide) and chloride channel (NPPB) inhibitors. Real-time PCR analysis confirmed the expression of NKCC1, the ubiquitous Na(+)-K(+)-2Cl(-) cotransporter and cystic fibrosis transmembrane regulator (CFTR) in mCCD-N21 cells. Tubule enlargement and cyst formation were prevented by inhibitors of Na(+)-K(+)-2Cl(-) cotransporters (bumetanide or ethacrynic acid) or CFTR (NPPB or CFTR inhibitor-172). These results further support the notion that cAMP signaling plays a key role in renal cyst formation, at least in part by promoting chloride-driven fluid secretion. This new in vitro model of tubule-to-cyst conversion affords a unique opportunity for investigating the molecular mechanisms that govern the architecture of epithelial tubes, as well as for dissecting the pathophysiological processes underlying cystic kidney diseases.