Mesenchymal stem cells and adipogenesis in hemangioma involution

Area of Science:

• Pediatric Oncology
• Developmental Biology
• Stem Cell Biology

Background:

• Infantile hemangioma is a common benign vascular tumor in infants, characterized by rapid proliferation followed by spontaneous involution.
• The mechanisms driving the adipogenesis (fat cell formation) during hemangioma regression remain largely unknown.
• Mesenchymal stem cells (MSCs) are multipotent stem cells with the capacity to differentiate into various cell types, including adipocytes.

Purpose of the Study:

• To investigate the presence and role of mesenchymal stem cells (MSCs) within infantile hemangiomas.
• To determine if hemangioma-derived MSCs possess adipogenic potential and if this correlates with the tumor's growth phase.
• To explore the cellular mechanisms underlying the spontaneous regression of infantile hemangioma.

Main Methods:

• Isolation of MSCs from proliferating and involuting infantile hemangiomas using selective adherence to culture dishes.
• Characterization of isolated hemangioma-derived MSCs (Hem-MSCs) by analyzing cell surface markers and comparing them to bone marrow-derived MSCs.
• Assessment of multilineage differentiation potential, with a focus on adipogenesis, and quantification of adipogenic Hem-MSCs in different tumor phases and normal skin.
• Analysis of X-chromosomal inactivation patterns to determine the clonal origin of Hem-MSCs.

Main Results:

• Mesenchymal stem cells (MSCs) were successfully isolated from infantile hemangiomas (Hem-MSCs) and exhibited characteristic MSC surface markers.
• Hem-MSCs demonstrated robust multilineage differentiation potential, notably strong adipogenic capacity that was higher in proliferating-phase tumors.
• The number of adipogenic Hem-MSCs was significantly greater in proliferating hemangiomas compared to involuting ones and normal infantile skin.
• Hem-MSCs showed random X-chromosomal inactivation, indicating a non-clonal origin.

Conclusions:

• Mesenchymal stem cells (MSCs) are a previously unrecognized cellular component of infantile hemangiomas.
• The identified Hem-MSCs possess significant adipogenic potential, suggesting they play a crucial role in the fat tissue formation during hemangioma involution.
• These findings provide novel insights into the cellular and molecular mechanisms driving the spontaneous regression of infantile hemangioma.