Continuous Low-Intensity Ultrasound Improves Cartilage Repair in Rabbit Model of Subchondral Injury.

Subchondral drilling (SD), a bone marrow stimulation technique, is used to repair cartilage lesions that lack regenerative potential. Cartilage repair outcomes upon SD are typically fibrocartilaginous in nature with inferior functionality. The lack of cues to foster the chondrogenic differentiation of egressed mesenchymal stromal cells upon SD can be attributed for the poor outcomes. Continuous low-intensity ultrasound (cLIUS) at 3.8 MHz is proposed as a treatment modality for improving cartilage repair outcomes upon marrow stimulation. Bilateral defects were created by SD on the femoral medial condyle of female New Zealand white rabbits (n = 12), and the left joint received cLIUS treatment (3.8 MHz, 3.5 Vpp, 8 min/application/day) and the contralateral right joint served as the control. On day 7 postsurgery, synovial fluid was aspirated, and the cytokine levels were assessed by Quantibody™ assay. Rabbits were euthanized at 8 weeks and outcomes were assessed macroscopically and histologically. Defect areas in the right joints exhibited boundaries, incomplete fill, irregular cartilage surfaces, loss of glycosaminoglycan (GAG), and absence of chondrocytes. In contrast, the repaired defect area in the joints that received cLIUS showed complete fill, positive staining for GAG with rounded chondrocyte morphology, COL2A1 staining, and columnar organization. Synovial fluid collected from cLIUS-treated left knee joints had lower levels of IL1, TNFα, and IFNγ when compared to untreated right knee joints, alluding to the potential of cLIUS to mitigate early inflammation. Further at 8 weeks, left knee joints (n = 12) consistently scored higher on the O'Driscoll scale, with a higher percent hyaline cartilage score. No adverse impact on bone or change in the joint space was noted. Upon a single exposure of cLIUS to TNFα-treated cells, nuclear localization of pNFκB and SOX9 was visualized by double immunofluorescence and the expression of markers associated with the NFκB pathway was assayed by quantitative real-time polymerase chain reaction. cLIUS extends its chondroprotective effects by titrating pNFκB levels, preventing its nuclear translocation, while maintaining the expression of SOX9, the collagen II transcription factor. Our combined results demonstrate that healing of chondral defects treated with marrow stimulation by SD can be accelerated by employing cLIUS regimen that possesses chondroinductive and chondroprotective properties. Impact statement Repair of cartilage represents an unsolved biomedical burden. In vitro, continuous low-intensity ultrasound (cLIUS) has been demonstrated to possess chondroinductive and chondroprotective potential. To our best knowledge, the use of cLIUS to improve cartilage repair outcomes upon marrow stimulation, in vivo, has not been reported and our work reported here fills that gap. Our results demonstrated enhanced cartilage repair outcomes under cLIUS (3.8 MHz) in a rabbit model of subchondral injury by subchondral drilling. Enhanced repair stemmed from mesenchymal stem cell differentiation in vivo and the subsequent synthesis of articular cartilage-specific matrix.

Deferasirox for iron chelation in multitransfused children with sickle cell disease; long-term experience in the East London clinical haemoglobinopathy network.

Deferasirox (DFX) has been licensed for iron chelation in patients with sickle cell disease (SCD), but there is limited data on its long-term efficacy and safety in children. This retrospective study included 62 regularly transfused children managed in the East London and Essex Clinical Haemoglobinopathy Network (mean age 9.2 ± 3.2 yr). Efficacy measurements consisted of monthly serum ferritin (SF) and annual R2 MRI-estimated liver iron concentration (LIC), and safety markers included serum creatinine and alanine aminotransferase (ALT). The mean duration of DFX treatment was 2.5 ± 1.4 yr, and mean dose at 36 months was 25 mg/kg/d. Mean SF at initiation of treatment was 2542 ± 952 ng/mL and increased to 4691 ± 2255 ng/mL at 36 months (P = 0.05). Mean LIC on first scan was 10.3 mg/g dry weight and did not decrease significantly on follow-up scans. There was a significant correlation between relative change in LIC and in SF (R(2) = 0.66, P < 0.001). Reversible transaminitis episodes, probably due to drug-induced hepatitis, were noted in 53% of patients. Responses to an adherence and acceptability questionnaire indicated that more than 50% of children had difficulties in taking DFX, commonly because of unpleasant taste. Our results show that more than 50% of children with SCD have inadequate control of iron overload with DFX. It is not clear whether this is because of frequent dose interruptions, poor tolerability and adherence, or poor efficacy of the drug. We recommend further studies to confirm these findings and to optimise iron chelation in this population.

Clinical outcomes in children with sickle cell disease living in England: a neonatal cohort in East London.

BACKGROUND AND OBJECTIVES: We investigated outcomes in a UK neonatal cohort as a benchmark for care of children with sickle cell disease (SCD). DESIGN AND METHODS: Two-hundred and fifty-two children (180 with hemoglobin [Hb] SS, 64 with HbSC, and 8 with HbS/beta thalassemia), identified during 1983-2005 by universal birth screening in East London, were followed in a hospital and community-based program which included penicillin V prophylaxis from 3 months of age, 23-valent pneumococcal polysaccharide vaccine from 1993, conjugate pneumococcal vaccine from 2002 and transcranial Doppler screening from 1991. RESULTS: At the end of 2005, there were 2158 patient years of observation. The median age of the patients was 7.8 (interquartile range 3.3-13.0) years, and 2.8% of those enrolled had been lost to follow-up. The estimated survival of children with HbSS at 16 years was 99.0% (95% confidence interval, CI, 93.2 to 99.9%) and pneumococcal sepsis rate was 0.3 (95% CI 0.1-0.8) episodes per 100 patient-years. The risk of overt stroke was 4.3% (95%CI 1.5 to 11.4%) and could be further reduced by transcranial Doppler screening from infancy and transfusing all children with high-risk scans. No deaths, strokes or episodes of pneumococcal sepsis were observed in children with HbSC or HbS/beta thalassemia. The mortality rates from HbSS were significantly lower than those in other reported cohorts. INTERPRETATION AND CONCLUSIONS: Mortality in childhood SCD can virtually be eliminated in a well-resourced health service setting linking community-based care with a specialized, hospital-based center. SCD continues to cause substantial morbidity from acute complications and chronic organ damage. We recommend setting up of clinical networks to optimize the management of SCD.