The influence of synovial inflammation and hyperplasia on symptomatic outcomes up to 2 years post-operatively in patients undergoing partial meniscectomy.

OBJECTIVE: Synovitis is associated with pain and other symptoms in patients with knee osteoarthritis (OA), and in patients with meniscal tears even in the absence of radiographic OA. Patients undergoing arthroscopic partial meniscectomy were followed for 2 years to determine whether synovitis predicts post-operative symptoms. DESIGN: Thirty-three patients scheduled for arthroscopy were recruited for this pilot study. Symptoms were assessed using a knee pain scale, the Lysholm score, and the short form-12 (SF-12(®)) pre-operatively and at 16 weeks, 1 year and 2 years post-operatively. Synovial inflammation and hyperplasia were graded on surgical biopsies. Linear mixed effects models were tested to determine whether inflammation or hyperplasia is associated with outcome scores over time. RESULTS: Lysholm scores and SF-12(®) physical component sub-scores were worse pre-operatively in patients with inflammation (Lysholm: 52.42 [95% confidence interval (CI) 42.37, 62.47] vs 72.38 [66.03, 78.72], P < 0.001; SF-12: 36.81 [28.26, 45.37] vs 46.23 [40.14, 52.32], P < 0.05). Up to 2-years post-operatively, patients with inflammation achieved mean scores similar to those without inflammation. As a result, the mean improvement in Lysholm scores was 13.01 [1.48-24.53] points higher than patients without inflammation, P = 0.03. 33% (4/12) of patients with inflammation still had fair to poor Lysholm scores 2 years after surgery compared to 7% (1/15, P=0.14) without inflammation. No association between hyperplasia and symptoms was noted. CONCLUSIONS: In this pilot study of patients undergoing partial meniscectomy, synovial inflammation was associated with worse pre-operative symptoms, but not with poorer outcomes in the first 2 years post-arthroscopy. Larger cohorts and longer follow-up should be pursued to confirm this relationship, and determine if the initial response is sustained.

An allelic association implicates myeloperoxidase in the etiology of acute promyelocytic leukemia.

Myeloperoxidase (MPO) catalyzes a reaction between chloride and hydrogen peroxide to generate hypochlorous acid and other reactive compounds that have been linked to DNA damage. The MPO gene is expressed at high levels in normal myeloid precursors and in acute myeloid leukemias (AMLs) which are clonal derivatives of myeloid precursors that have lost the ability to differentiate into mature blood cells. Two MPO alleles differ at -463 G/A within a cluster of nuclear receptor binding sites in an Alu element. The -463 G creates a stronger SP1 binding site and retinoic acid (RA) response element (RARE) in the allele termed Sp. In this study, we investigate potential links between MPO genotype, MPO expression level, and myeloid leukemia. The SpSp MPO genotype is shown to correlate with increased MPO mRNA levels in primary myeloid leukemia cells. This higher-expressing SpSp genotype is further shown to be overrepresented in acute promyelocytic leukemia-M3 (APL-M3) and AML-M4, suggesting that higher levels of MPO are associated with an increased risk for this subset of leukemias.