Publications

Integrins are transmembrane heterodimeric receptors that contribute to diverse biological functions and play critical roles in many human diseases. Studies using integrin subunit knockout mice and inhibitory antibodies have identified important roles for nearly every integrin heterodimer and led to the development of a number of potentially useful therapeutics. One notable exception is the αvβ1 integrin. αv and β1 subunits are individually present in numerous dimer pairs, making it challenging to infer specific roles for αvβ1 by genetic inactivation of individual subunits, and αvβ1 complex-specific blocking antibodies do not yet exist. We therefore developed a potent and highly specific small-molecule inhibitor of αvβ1 to probe the function of this understudied integrin. We found that αvβ1, which is highly expressed on activated fibroblasts, directly binds to the latency-associated peptide of transforming growth factor-β1 (TGFβ1) and mediates TGFβ1 activation. Therapeutic delivery of this αvβ1 inhibitor attenuated bleomycin-induced pulmonary fibrosis and carbon tetrachloride-induced liver fibrosis, suggesting that drugs based on this lead compound could be broadly useful for treatment of diseases characterized by excessive tissue fibrosis.

OBJECTIVE

To identify factors associated with clinical outcome in patients with lupus nephritis.

METHODS

Data from the Aspreva Lupus Management Study (ALMS) were analysed. Using multivariate analysis, we assessed the prognostic value of demographic, clinical, laboratory and histopathological features on the frequency of either complete remission (CR) or treatment failure (TF) during the maintenance phase.

RESULTS

Among the 370 subjects who entered the trial (complete population), non-Hispanic ethnicity was associated with a higher likelihood of CR (OR=2.0). Several factors were independently associated with a greater likelihood of TF, including: (1) anti-double-stranded DNA (anti-dsDNA) at trial entry (OR=12.7), (2) failure to reduce anti-dsDNA within 8 weeks (OR=2.9) and (3) failure to reduce urine protein:creatinine ratio (UP/C) by ≥25% within 8 weeks (OR=2.6). Among the 227 subjects who entered the maintenance phase (maintenance population), baseline estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m(2) was associated with a greater likelihood of CR (OR=2.0), and UP/C >1 at the end of induction was associated with a lower likelihood of CR (OR=0.3). Induction treatment with intravenous cyclophosphamide (IVC) was associated with a lower likelihood of TF (OR=0.5), while lack of treatment with antimalarials (OR=2.4), failure to reduce anti-dsDNA during the first 8 weeks of induction (OR=3.5), failure to reduce UP/C during the first 8 weeks of induction (OR=2.1) and anti-dsDNA positivity at the end of induction (OR=8.3) were independently associated with a greater likelihood of TF.

CONCLUSIONS

This analysis demonstrates that levels of anti-dsDNA and UP/C during induction treatment are independently associated with renal outcome over the ensuing 3 years in both the complete and maintenance populations. Ethnicity is associated with renal outcome in just the complete population, and eGFR, induction treatment and treatment with antimalarials are associated with renal outcome in just the maintenance population.