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INTRODUCTION: A post hoc analysis of three randomized controlled trials of abatacept in rheumatoid arthritis (RA) was conducted to explore the effect of abatacept on fatigue in RA and its correlation with other outcomes. METHODS: In this analysis of AGREE (early RA) and AIM and ATTAIN (established RA), changes in baseline fatigue (0-100 mm scale), pain, sleep (AIM and ATTAIN only) and Disease Activity Score (DAS) 28 (C-reactive protein; CRP) were calculated at days 29, 85, and 169. Agreement between improvements ≥minimum clinically important differences (MCID) in fatigue and other outcomes were evaluated using agreement statistics (kappa) in each study and at each time point. RESULTS: Of 1536 patients (mean disease duration: 6.2 months [AGREE], 8.5 years [AIM], 12.2 years [ATTAIN]), mean (SE) decreases in fatigue from baseline to day 169 with abatacept were 28.9 (1.7), 25.3 (1.2), and 21.9 (1.6) in AGREE, AIM, and ATTAIN, respectively, with corresponding decreases of 16.0, 13.7, and 13.4 at day 29. Most patients (67.8%; 624/920) reported improvements ≥MCID in fatigue with abatacept at day 169; 79.2% (671/847) and 57.8% (388/671) reported improvements ≥MCID in pain and sleep, respectively; 18.9% (158/836) were in DAS28 (CRP) remission. Agreement between improvement in fatigue and other outcomes was low (kappa range 0.30-0.51 [pain], 0.14-0.26 [sleep], and 0.02-0.12 [DAS28 (CRP) remission]). CONCLUSIONS: Abatacept resulted in rapid improvements in fatigue and pain in patients with RA. However, low agreement between improvements in these outcomes indicates that fatigue and other outcomes including pain and sleep may represent different domains of response. FUNDING: Bristol-Myers Squibb.
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Skeletal unloading induced by hindlimb suspension in rats reduces bone formation and induces osteopenia, but its effect on adipogenesis is unknown. We assessed the effects of unloading and transforming growth factor (TGF) beta2 on bone marrow stromal cell adipocyte differentiation in relation with osteoblast differentiation. Skeletal unloading rapidly (4-7 days) decreased osteoblast transcription factor Runx2, osteocalcin (OC), and type I collagen messenger RNA (mRNA) levels and reduced bone formation in the long bone metaphysis. Conversely, unloading increased expression of the adipocyte transcription factor peroxisome proliferator-activated receptor gamma2 (PPARgamma2) at 4 days and increased expression of the adipocyte differentiation genes lipoprotein lipase (LPL) and aP2 in the bone marrow stroma at 7 days. Consistently, unloading increased the number and volume of adipocytes in the bone marrow stroma. Continuous (0-7 days) and late (4-7 days) treatments with TGF-beta2 corrected the abnormal expression of Cbfa1/Runx2, OC, and type I collagen mRNAs and normalized bone formation in unloaded metaphyseal bone. Moreover, both TGF-beta2 treatments decreased PPARy2 and C/EBPalpha mRNA levels at 4 days and normalized aP2 and LPL expression and adipocyte number and volume at 7 days. These results show that skeletal unloading increases adipocyte differentiation concomitantly with inhibition of osteoblast differentiation. These abnormalities are prevented and reversed by TGF-beta2, suggesting a role for TGF-beta in the control of adipogenic differentiation in the bone marrow stroma.
