From Growth Factors to Structure: PDGF and TGF-β in Granulation Tissue Formation. A Literature Review

Platelet-Derived Growth Factors (PDGFs) and Transforming Growth Factor β (TGFβ) are pivotal in orchestrating the complex wound healing process, particularly in granulation tissue formation. This review aims to comprehensively examine the roles of PDGF alongisde TGFβ in granulation tissue formation and their implications for abnormal wound healing. PDGFs, as homodimeric or heterodimeric combinations, such that PDGF-AA, PDGF-AB and PDGF-BB stimulate fibroblast proliferation and extracellular matrix synthesis, which is crucial for tissue repair. TGFβ, with its three isoforms, influences granulation tissue through diverse functions, with TGFβ-1 pivotal in fibrosis formation. Understanding their signalling pathways, notably PDGF's engagement with PDGF receptors and subsequent activation of cellular pathways, illuminates their roles in wound healing cascades. Excessive granulation, a complication of abnormal wound healing, involves dysregulated PDGF and TGFβ activity, leading to hypertrophic scar formation. Clinical management, particularly in ophthalmology, addresses excessive granulation's impact on procedures like endo-dacryocystorhinostomy. Strategies employing steroid agents and Mitomycin-C aim to mitigate ostium granulation. The potential use of PDGF receptor blockers, such as olaratumab, warrants further investigation for managing excessive granulation. In conclusion, PDGF and TGFβ emerge as critical regulators in granulation tissue formation, underscoring their significance in wound healing processes and offering avenues for therapeutic intervention.