Publications

BACKGROUND

To date, no management approach has proven to be efficacious for the treatment of idiopathic pulmonary fibrosis (IPF). Consequently, therapeutic options remain controversial and confusing for many clinicians. We sought to formally review available evidence on treatment options for IPF and to have a diverse panel of physicians rate the "appropriateness," "inappropriateness," or "uncertainty" of some of the available therapeutic options.

METHODS

The RAND/UCLA Appropriateness Method was used to review and rate multiple clinical scenarios for the treatment of IPF. The panel was composed of nine physicians from geographically diverse areas who received a systematic review on the risks and benefits of commonly used treatments for IPF as background.

RESULTS

A total of 324 clinical scenarios were rated: 25% as appropriate; 39%, uncertain; and 36%, inappropriate. The panel disagreed about 12% of the therapy indications in the final ratings, falling from 26% in the first-round ratings.

CONCLUSIONS

Key themes emerged from the consensus process. Lacking evidence for a definitive therapy, it was considered most appropriate to enroll eligible patients in clinical trials and refer eligible patients for transplant evaluation. For patients without access to clinical trials, the committee was not unanimous regarding treatment recommendations. It was considered inappropriate for patients with a confident diagnosis of IPF to be treated with corticosteroids as the sole agent: corticosteroids should be used in conjunction with azathioprine. With progressive disease despite such combination use, there was agreement for the use of interferon gamma-1b in patients unwilling or unable to participate in available clinical trials.

In this study, we asked if a naturally occurring HIV-1 variant exists that circumvents CypA dependence in human cells. To address this issue, we sought viruses for CypA independence using Debio-025, a cyclosporine A (CsA) analog that disrupts CypA-capsid interaction. Surprisingly, viral variants from the Main group replicate even in the presence of the drug. Sequencing analyses revealed that these viruses encode capsid substitutions within the CypA-binding site (V86P/H87Q/I91V/M96I). When we introduced these substitutions into viruses that normally rely on CypA for replication, these mutants no longer depended on CypA, suggesting that naturally occurring capsid substitutions obviate the need for CypA. This is the first demonstration that isolates from the Main group naturally develop CypA-independent strategies to replicate in human cells. Surprisingly, we found that these capsid substitutions render HIV-1 capable of infecting Owl monkey (OMK) cells that highly restrict HIV-1. OMK cell resistance to HIV-1 is mediated via TRIM-Cyp, which arose from a retrotransposition of CypA into the TRIM5 alpha gene. Interestingly, saturation experiments suggest that the Pro86/Gln87/Val91/Ile96 capsid core is "invisible" to TRIM-Cyp. This study demonstrates that specific capsid substitutions can release HIV-1 from both CypA dependence in human cells and TRIM-Cyp restriction in monkey cells.

Gamma-melanocyte stimulating hormone (gamma-MSH) is a circulating natriuretic peptide hormone derived from proopiomelanocortin (POMC); its concentration in plasma and pituitary POMC mRNA abundance, increase in rats ingesting a high-sodium diet (HSD, 8% NaCl) compared with a low-sodium diet (LSD, 0.07% NaCl). RT-PCR of rat kidney RNA demonstrated reaction products of the expected size in both cortex and medulla for MC3-R, MC4-R, and MC5-R mRNA; no signal for MC1-R or MC2-R was detected. Relative to beta-actin or cyclophilin, abundance of the three receptor transcripts after 1 wk of the LSD was approximately equal in both cortex and medulla. After 1 wk of the HSD, mRNA abundance of MC4-R and MC5-R was unchanged, whereas that of MC3-R in medulla more than doubled, the ratio of MC3-R/beta-actin signal increasing from 0.38 +/- 0.04 on LSD to 0.84 +/- 0.04 on HSD (P < 0.001). No significant increase occurred in the cortex. The increase in MC3-R expression induced by dietary sodium was observed in inner medullary collecting duct (IMCD) cells isolated from the kidneys of HSD rats, suggesting that these cells were the major site of receptor expression in the medulla. Immunoblots of whole medullary and IMCD cell homogenates detected MC3-R immunoreactive protein; its expression was twice as great in samples from HSD vs. LSD rat kidneys, paralleling the increase in MC3-R mRNA abundance on the HSD. No changes in MC4-R or MC5-R protein expression were observed. Incubation of IMCD cell suspensions with increasing concentrations of gamma2-MSH led to increased cAMP accumulation, with values from rats on the HSD being roughly double the values from LSD rats. Intrarenal infusion of gamma2-MSH (500 fmol/min) increased sodium and cAMP excretion from the infused but not contralateral kidney of HSD rats, while having no effect in LSD rats. These data show that MC3-R is expressed in rat IMCD cells in a manner modulated by dietary sodium intake. Because MC3-R is the receptor with which gamma-MSH interacts, our findings suggest the existence of a sodium-regulating system, activated in response to a HSD, which increases urinary sodium excretion to balance the high-sodium intake.

Apoptosis is a critical process in normal mammary gland development and the rapid clearance of apoptotic cells prevents tissue injury associated with the release of intracellular antigens from dying cells. Milk fat globule-EGF-factor 8 (Mfge8) is a milk glycoprotein that is abundantly expressed in the mammary gland epithelium and has been shown to facilitate the clearance of apoptotic lymphocytes by splenic macrophages. We report that mice with disruption of Mfge8 had normal mammary gland development until involution. However, abnormal mammary gland remodeling was observed postlactation in Mfge8 mutant mice. During early involution, Mfge8 mutant mice had increased numbers of apoptotic cells within the mammary gland associated with a delay in alveolar collapse and fat cell repopulation. As involution progressed, Mfge8 mutants developed inflammation as assessed by CD45 and CD11b staining of mammary gland tissue sections. With additional pregnancies, Mfge8 mutant mice developed progressive dilatation of the mammary gland ductal network. These data demonstrate that Mfge8 regulates the clearance of apoptotic epithelial cells during mammary gland involution and that the absence of Mfge8 leads to inflammation and abnormal mammary gland remodeling.