Why is UIP peripheral?

ABSTRACT

Introduction

The radiology pattern associated with IPF is called UIP. It is unique because unlike any other form of fibrosis it is peripheral in its distribution. We investigated the peripheral nature of UIP and why it was a key feature of IPF the deadliest of the ILDS.

Areas covered

It is not enough to say that UIP is peripheral but instead as scientists we must ask ourselves why it is peripheral. This review dives into the published hypothesis that includes vascular insult, tensile forces, microaspiration, and inflammation and looks at the pros and cons for each argument, and ultimately comes to its own conclusion. PubMed searches using the below keywords were used to identify papers that described pathogenesis of IPF with regard to a particular theory.

Expert opinion

In this paper, we will review four ideas that support why UIP is peripheral and propose the most likely explanation given what is currently known about the pathophysiology of IPF.

KEYWORDS:

• Usual interstitial pneumonitis
• chest CT
• tensile forces
• vascular insult
• gastroesophageal reflux
• inflammation
• infection

Article highlights

• The cause(s) of IPF and its peripheral appearance have yet to be determined.

• Vascular injury may be a driving force of IPF.

• Aging lungs show increased tensile forces, which are greatest at the periphery of the lungs.

• GERD and inflammation may also play a role in pathogenesis of IPF.

• Trials of medical therapy have been disappointing and only prevent progression of disease.

Declaration of Interests

M Salvatore is a speaker and consultant for and has received grant funding from Genentech and Boehringer Ingelheim. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.