[Delayed graft function : an ongoing clinical challenge]. / Reprise retardée de fonction du greffon après transplantation rénale : un challenge clinique toujours d'actualité.

Delayed Graft Function (DGF) is defined as the need for dialysis during the first week after transplantation. DGF is frequent and mostly derived from the ischemia/reperfusion cascade to which the graft is subjected throughout the transplantation process. A graft biopsy is recommended after 7 days of DGF to exclude an episode of acute rejection. Note that DGF per se is associated with an increased risk of acute graft rejection, as well as with a shorter long-term graft survival. Several strategies are being studied to mitigate the ischaemic damage, thereby improving graft quality. Among these, cellular therapy using mesenchymal stromal cells (MSC) is promising, in particular via the administration of MSC in the machine perfusion during the preservation of the graft. We will discuss here the different definitions of DGF and the main predictive factors of DGF, as well as the impact on the graft outcomes. The current strategies to prevent DGF will be briefly reviewed.

La reprise retardée de fonction du greffon rénal (DGF en anglais pour Delayed Graft Function), définie notamment par la nécessité de dialyse durant la 1ère semaine après transplantation, reste un événement fréquent. La DGF résulte principalement des phénomènes d'ischémie/reperfusion auxquels le greffon est soumis tout au long du processus de transplantation. Néanmoins, une biopsie du greffon est préconisée après 7 jours de DGF afin d'exclure une cause non ischémique telle qu'un rejet aigu. La DGF est per se associée à un risque accru de rejet du greffon, ainsi qu'à une moins bonne survie du greffon rénal au long cours. Plusieurs stratégies sont étudiées afin d'atténuer les dommages ischémiques et améliorer la qualité du greffon. Parmi celles-ci, la thérapie cellulaire par cellules stromales mésenchymateuses est prometteuse, notamment via l'administration de celles-ci dans la machine de perfusion lors de la préservation du greffon. Nous aborderons les différentes définitions de la DGF ainsi que ses principaux facteurs prédictifs, l'impact sur le devenir du greffon et, brièvement, les stratégies actuelles dans le cadre de la prévention de la DGF.

Radiotherapy Advances in Renal Disease-Focus on Renal Ischemic Preconditioning.

Ionizing irradiation is widely applied as a fundamental therapeutic treatment in several diseases. Acute kidney injury (AKI) represents a global public health problem with major morbidity and mortality. Renal ischemia/reperfusion (I/R) is the main cause of AKI. I/R injury occurs when blood flow to the kidney is transiently interrupted and then restored. Such an ischemic insult significantly impairs renal function in the short and long terms. Renal ischemic preconditioning (IPC) corresponds to the maneuvers intended to prevent or attenuate the ischemic damage. In murine models, irradiation-induced preconditioning (IP) renders the renal parenchyma resistant to subsequent damage by activating defense pathways involved in oxidative stress, angiogenesis, and inflammation. Before envisioning translational applications in patients, safe irradiation modalities, including timing, dosage, and fractionation, need to be defined.

Osteomodulin downregulation is associated with osteoarthritis development.

Abnormal subchondral bone remodeling leading to sclerosis is a main feature of osteoarthritis (OA), and osteomodulin (OMD), a proteoglycan involved in extracellular matrix mineralization, is associated with the sclerotic phenotype. However, the functions of OMD remain poorly understood, specifically in vivo. We used Omd knockout and overexpressing male mice and mutant zebrafish to study its roles in bone and cartilage metabolism and in the development of OA. The expression of Omd is deeply correlated with bone and cartilage microarchitectures affecting the bone volume and the onset of subchondral bone sclerosis and spontaneous cartilage lesions. Mechanistically, OMD binds to RANKL and inhibits osteoclastogenesis, thus controlling the balance of bone remodeling. In conclusion, OMD is a key factor in subchondral bone sclerosis associated with OA. It participates in bone and cartilage homeostasis by acting on the regulation of osteoclastogenesis. Targeting OMD may be a promising new and personalized approach for OA.