Increased hyaluronan expression at distinct time points in acute lymphedema

Area of Science:

• Biomedical Science
• Cell Biology
• Physiology

Background:

• Lymphedema causes chronic fluid accumulation and tissue swelling due to lymphatic dysfunction.
• The role of glycosaminoglycans (GAGs) in lymphedema's interstitial environment is largely unknown.
• Understanding GAGs may reveal new therapeutic targets for lymphedema.

Purpose of the Study:

• To investigate the relationship between hyaluronan (HA) and sulfated GAGs with tissue swelling in a mouse model of lymphedema.
• To determine if HA or sulfated GAGs are upregulated during acute lymphedema.
• To explore the potential role of HA in mitigating lymphedema-associated edema.

Main Methods:

• Utilized a mouse tail model to induce acute lymphedema.
• Quantified HA and sulfated GAG concentrations in relation to tail swelling over time.
• Administered hyaluronidase to assess the functional impact of HA degradation on edema.

Main Results:

• Hyaluronan (HA) levels increased significantly with skin swelling, particularly during the declining phase of edema.
• HA upregulation was associated with a decrease in tail swelling, suggesting a counter-edema effect.
• Sulfated GAGs, including chondroitin sulfate, did not show significant regulation in response to swelling.
• Inhibiting HA with hyaluronidase exacerbated tail swelling, confirming HA's role in reducing edema.

Conclusions:

• Hyaluronan (HA), but not sulfated GAGs, is upregulated in the interstitial environment during acute lymphedema in mice.
• Increased HA expression appears to be a natural adaptive response to counteract tissue swelling and edema.
• These findings suggest HA may play a protective role in lymphedema by reducing capillary filtration and enhancing fluid outflow.