# Photodynamic Therapy for Aortic Aneurysms

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2024 · $287,000

## Abstract

Project Summary
Abdominal aortic aneurysms (AAA) are a leading cause of death worldwide, and no medical treatment is currently
available. It is now accepted that aneurysm growth is related to chronic progressive tissue destruction secondary
to vascular inflammation, resulting in the breakdown of extracellular matrix (ECM) proteins. We have shown that
a tailored Photodynamic Therapy (PDT) protocol in a mouse model can halt aortic aneurysm growth 21 days
after AAA induction. Photodynamic therapy has been shown to enhance cross-linking of collagen, a key
component of aortic ECM. This cross-linking substantially increases the strength of ECM. Further, in oncologic
studies, PDT appears to selective kill rapidly dividing cells with an affinity for proliferating immune cells.
Therefore, we hypothesize that applying PDT to AAA will enhance ECM cross-linking and eradicate proliferating
immune cells within the adventitia layer of the vascular wall. Our specific aims are designed to test these
hypotheses and determine the mechanism of action behind PDT treatment of AAA. In Aim 1 we will compare the
changes to ECM proteins after PDT to what occurs in control mice. We will also evaluate matrix metalloproteases
(MMPs) and tissue inhibitors of MMPs (TIMPs), key enzymatic regulators of ECM degradation. In Aim 2 we will
investigate the changes in immune cell subpopulations within aortic tissue after PDT. In addition, we will use
unbiased analysis to identify changes to gene expression of inflammatory proteins within aortic tissue after
delivery of PDT. As our preliminary findings show that PDT can have a powerful effect on AAA growth, analysis
of the molecular changes that coincides with this deceleration in growth may lead to a better understanding of
the mechanisms that drive AAA progression. In addition, understanding the therapeutic mechanism of PDT may
allow PDT to adapted for use in human AAA disease.

## Key facts

- **NIH application ID:** 10870978
- **Project number:** 1R21HL173856-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Adam Oskowitz
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $287,000
- **Award type:** 1
- **Project period:** 2024-08-01 → 2026-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10870978

## Citation

> US National Institutes of Health, RePORTER application 10870978, Photodynamic Therapy for Aortic Aneurysms (1R21HL173856-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10870978. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*