Platelet-derived growth factor
Platelet-derived growth factor (PDGF) is the “Project Manager” of the wound-healing cascade. Stored in platelet α-granules, it is the first signal released upon injury or treatment. Unlike TGF-β1, which builds the “bricks” ( collagen), PDGF is responsible for recruitment and mobilisation. It acts as a potent chemoattractant, “calling” fibroblasts and dermal papilla cells to the site of action and telling them to multiply. Crucially, PDGF-BB also stabilises new blood vessels by recruiting pericytes. In clinical practice, we view PDGF as the initiator: it refills the cell population so that subsequent signals (like Polynucleotides or further iPRF sessions) have a larger “workforce” to act upon.
Platelet-derived growth factor is a family of dimeric signalling proteins composed of disulphide-bonded A and B polypeptide chains, producing three isoforms present in human platelets: PDGF-AA (homodimer), PDGF-AB (heterodimer), and PDGF-BB (homodimer). [10] A fourth isoform, PDGF-DD, is expressed by other cell types but is absent from platelet preparations. [1] All three platelet isoforms are packaged in alpha granules and released when platelets are activated by calcium chloride in iPRF preparation, by thrombin in the coagulation cascade, or by the physical stimulus of injection into tissue.
| Isoform | Receptor | Target Cell Types | Primary Clinical Effect |
|---|---|---|---|
| PDGF-AA | PDGFR−αα | Fibroblasts, Glial cells | General proliferation; cell survival. |
| PDGF-AB | PDGFR−αα / αβ | Fibroblasts, MSCs | Primary “chemotactic” signal in PRP/iPRF. |
| PDGF-BB | PDGFR−αα / αβ / ββ | Pericytes, Fibroblasts | Vessel maturation; Dermal Papilla activation. |
PDGF signals through two receptor tyrosine kinases – PDGFR-α and PDGFR-β – with isoform-specific binding affinities. PDGF- AA binds exclusively to PDGFR-α homodimers; PDGF-BB binds both PDGFR-α and PDGFR-β, including PDGFR-β homodimers; and PDGF-AB binds both receptor types but with different efficiencies. [1] This isoform-receptor specificity matters in tissue because different cell types express different receptor combinations, and it is PDGFR-β that is the primary pericyte receptor, with consequences for vascular stabilisation that are described below.
PDGF-AA
PDGF-AA is the homodimeric isoform formed from two A-chain polypeptides, binding exclusively to PDGFR-αα homodimers. Because PDGFR-α is the receptor most broadly expressed across fibroblasts and mesenchymal stromal cells, PDGF-AA has the widest fibroblast-targeting reach of the three platelet isoforms. Its primary biological role is cell survival and general proliferation rather than directed chemotaxis – it keeps recruited fibroblasts viable and cycling at the treatment site whilst PDGF-AB provides the directional migration signal. In wound healing, PDGF-AA is produced by activated platelets, macrophages, and keratinocytes, making it available across the proliferative phase of repair. In iPRF, PDGF-AA and PDGF-AB are the isoforms most enhanced relative to standard PRP preparations, reflecting the lower centrifugation speed preserving a richer platelet and leucocyte payload. [1] PDGF-AA is also the specific isoform secreted by transiently senescent wound-edge fibroblasts to drive myofibroblast differentiation – the mechanism described in the Cellular Senescence entity’s wound healing section.
PDGF-AB
PDGF-AB is the heterodimeric isoform formed from one A-chain and one B-chain polypeptide. It binds both PDGFR-αα homodimers and PDGFR-αβ heterodimers, giving it a broader receptor range than PDGF-AA and making it the dominant chemotactic isoform in PRP and iPRF preparations – the signal most responsible for orienting fibroblast migration toward the treatment zone rather than simply stimulating proliferation in place. [1] The distinction between chemotaxis (directed movement toward a gradient) and mitogenesis (cell division) matters here: PDGF-AB is primarily doing the former. In tissue, this makes it the recruitment coordinator – drawing fibroblasts and mesenchymal stromal cells through the ECM toward the site where TGF-β1 will subsequently activate collagen synthesis. PDGF-AB concentration in iPRF is enhanced relative to PRP, consistent with iPRF’s documented superiority in fibroblast migration assays. [14]
PDGF-BB
PDGF-BB is the homodimeric isoform formed from two B-chain polypeptides and has the broadest receptor binding of the three isoforms – activating PDGFR-αα, PDGFR-αβ, and PDGFR-ββ homodimers. This broad receptor range, and specifically its activation of PDGFR-β, gives PDGF-BB functions that the other isoforms cannot replicate. PDGFR-β is the primary receptor on pericytes – the perivascular cells responsible for vessel wall stabilisation and basement membrane deposition – making PDGF-BB the dominant signal for pericyte recruitment to newly formed blood vessel walls, as described in the vessel maturation section above. PDGF-BB is also the dominant motility signal for human dermal fibroblasts migrating on Type I collagen matrices, and its expression on dermal papilla cells through the same PDGFR-β pathway places hair follicle stimulation and vascular stabilisation within a shared mechanistic framework. [12] In aged and photodamaged skin, PDGF-BB-driven fibroblast migration is specifically impaired by ECM fragmentation – the MMP-degraded matrix provides a less permissive substrate for PDGFR-β-mediated motility, reducing the recruitment yield from the same growth factor signal. [5]
The Recruitment Function: What PDGF Actually Does
The most clinically important distinction in PDGF biology, and one frequently glossed over in aesthetics content, is that PDGF is primarily a recruitment and mobilisation signal rather than a collagen synthesis signal. In wound fibroblasts, both PDGF-AA and PDGF-BB actually downregulate steady-state levels of pro-α1(I) and pro-α1(III) collagen chain mRNAs in a dose-dependent manner. [4] This is not a failure of PDGF, it reflects its precise biological role. PDGF arrives at the wound site first, recruiting and proliferating the fibroblast population that will subsequently be activated for collagen production by TGF-β1. The two growth factors work in sequence: PDGF brings the workforce; TGF-β1 puts it to work.
PDGF-BB is the dominant motility signal for human dermal fibroblasts migrating on type I collagen matrices – the major chemotactic factor in serum driving fibroblast movement through the wound ECM. [5] PDGF-AB is the dominant chemotactic isoform in PRP preparations. [1] Together, the isoform combination in iPRF and PRP provides both the motility signal that moves fibroblasts through tissue and the chemotactic gradient that orients their direction toward the treatment zone.
In chronic wounds, where the normal repair cascade has stalled, PDGF expression is measurably reduced and whatever PDGF is present is degraded by the elevated protease activity that characterises chronic wound fluid. [13] Exogenous PDGF delivery (through iPRF, PRP, or recombinant PDGF preparations) provides the recruitment signal the tissue is no longer generating adequately on its own, restoring the first step in a cascade that has been stalled at its initiation.
The Regenerative Sequence (PDGF vs. TGF-β1)
| Phase | Dominant Growth Factor | Biological Command | Visible Outcome |
|---|---|---|---|
| Phase 1: Recruitment | PDGF | “Come to the site and divide.” | Reduced redness; initial healing. |
| Phase 2: Construction | TGF-β1 | “Stay here and build collagen.” | Improving skin density/texture. |
| Phase 3: Maturation | FGF-2 / PDGF-BB | “Stabilise vessels and matrix.” | Long-term structural integrity. |
PDGF-BB and Pericyte Recruitment: Vessel Stabilisation
One of the most mechanistically important and clinically underappreciated functions of PDGF-BB, particularly in the context of regenerative aesthetics, is its role in recruiting pericytes to newly formed blood vessel walls.
Pericytes are specialised perivascular cells that wrap around the endothelial tubes of microvessels, providing structural support, regulating vessel diameter, and critically, triggering the deposition of the vascular basement membrane that stabilises the vessel over time. Without pericyte coverage, newly formed endothelial tubes remain unstable, dilated, and structurally immature. [12]
Endothelial cells produce and secrete PDGF-BB as new vessels form and it is this EC-derived PDGF-BB that acts as the chemoattractant recruiting pericytes to the abluminal surface of the endothelial tube. Pericyte motility in three-dimensional collagen matrices is completely dependent on EC-derived signals: pericytes cultured without endothelial cells fail to move directionally at all. When PDGF-BB signalling through PDGFR-β on pericytes was blocked, pericyte association with EC tubes fell from approximately 85% to 60%. When both PDGF-BB and HB-EGF (a co-recruiter from the EGF family) were blocked simultaneously, pericyte association dropped to 35–40% with concomitant increases in vessel width and failure of basement membrane deposition. [12] In living embryos, blocking both signals produced vascular haemorrhage – direct confirmation that PDGF-BB-mediated pericyte recruitment is required for vessel structural integrity, not just a developmental nicety.
The consequence for vessel maturation is layered. When pericytes are recruited successfully through PDGF-BB signalling, they deposit collagen IV, laminin, fibronectin, nidogen, and perlecan along the endothelial abluminal surface – assembling the vascular basement membrane that stabilises vessel diameter, prevents haemorrhage, and provides the structural scaffold for long-term vessel integrity. [12] When pericyte recruitment fails through inadequate PDGF-BB, as occurs in diseases like diabetes where pericyte loss is a hallmark of microvascular dysfunction, vessels remain wide, unstable, and leak-prone.
This connects pericyte biology to the HSPG entity: perlecan, one of the basement membrane proteins deposited by pericytes during vessel maturation, is the primary HSPG growth factor reservoir in the dermis. PDGF-BB-driven pericyte recruitment therefore contributes not only to vascular stability but indirectly to ECM-bound FGF2 and VEGF reservoir maintenance – a connection that runs through multiple entities in the knowledge base.
PDGF and Dermal Papilla Cells
In the hair follicle, PDGFR-β is expressed on dermal papilla cells, placing them in the same receptor class as pericytes, which are themselves a specialised perivascular mesenchymal cell population with a shared developmental lineage. [9] PDGF in iPRF therefore activates DPCs through the same receptor pathway it uses to recruit and proliferate pericytes; a mechanistic convergence that explains part of iPRF’s effectiveness in both skin vascular support and hair follicle stimulation through a single growth factor payload.
PDGF Decline in Aged and Photodamaged Skin
Aged skin presents a PDGF signalling environment that is less responsive to the recruitment signals that iPRF delivers. Dermal fibroblast density declines with age and UV accumulation (fewer fibroblasts means fewer cells to recruit) and the ECM environment those fibroblasts would migrate through becomes progressively degraded by MMP-driven proteoglycan and collagen fragmentation. PDGF-mediated fibroblast migration requires intact ECM, specifically type I collagen, as the substrate for PDGFR-β-mediated motility. [5] A fragmented, MMP-degraded matrix is a less effective substrate for PDGF-driven fibroblast recruitment, meaning the same PDGF signal delivered into significantly aged or photodamaged skin recruits a smaller population into a less permissive migration environment.
Clinical Application
PDGF isn’t exclusive to iPRF and PRP. It sits at the centre of the wound healing cascade that almost every professional treatment in the portfolio triggers, one way or another. What varies is how each treatment interacts with it: some deliver it directly, some prompt the tissue to release its own, some improve the environment it operates in, and one modulates the downstream signalling it activates through an independent route entirely. Understanding those distinctions makes the treatment logic considerably more specific than “these treatments stimulate collagen production.”
iPRF and PRP: direct delivery
iPRF and PRP are the only treatments that deliver exogenous PDGF to the treatment zone – all three isoforms released from activated platelet alpha granules into the fibrin scaffold, then released sustained over days rather than arriving as a single bolus. [10] That sustained release matters because PDGF’s chemotactic effect is gradient-dependent. Fibroblasts migrate toward a PDGF concentration gradient; maintain the gradient over time and you sustain directional migration into the treatment zone; let it dissipate rapidly and the recruitment signal is brief.
What makes iPRF’s payload particularly well-designed, and this isn’t obvious from looking at the individual growth factors, is that PDGF and IGF-1 together are synergistic in a way that neither achieves alone. The 1986 PNAS wound study found that PDGF alone produced only modest connective tissue increases, and IGF-1 alone produced no significant morphological change at all. Together, they produced a 2.4-fold increase in newly formed connective tissue width and a 95% increase in epidermal thickness. [7] That synergy is inherent to iPRF’s combined growth factor payload and is part of why single growth factor preparations don’t replicate what iPRF achieves.
RF microneedling and thulium laser: triggering the body’s own PDGF
RF microneedling and thulium fractional laser create controlled tissue injury that triggers platelet activation and the natural wound healing cascade at the treatment site, and endogenous PDGF release from those activated platelets is part of that cascade. [13] The treatment is effectively prompting the tissue to release its own PDGF as part of the repair response it initiates.
Applying iPRF alongside or immediately post-procedure adds an amplified exogenous PDGF signal at exactly the moment the tissue’s own cascade is starting, augmenting the endogenous response rather than replacing it. A 2025 randomised controlled trial confirmed this directly: recombinant pure PDGF applied post-RF microneedling produced significantly better aesthetic outcomes at 30 days, reduced post-procedure redness, and greater patient satisfaction compared to standard post-procedure care. [6] The improvement was attributed to PDGF accelerating and coordinating the repair response that the RF treatment had initiated – the treatment did the triggering; the PDGF supported the follow-through.
Polynucleotides: preparing the ground PDGF recruits into
Polynucleotides don’t deliver PDGF and don’t directly upregulate it. Their relationship to PDGF is environmental and that’s precisely why the sequencing matters. PDGF-driven fibroblast migration requires intact type I collagen as the substrate fibroblasts move through. [5] In significantly aged or photodamaged tissue where MMP-driven ECM fragmentation has degraded that substrate, the PDGF recruitment signal is working with a depleted workforce navigating damaged terrain. Polynucleotide-mediated MMP suppression protects the collagen matrix that recruited fibroblasts would migrate through, meaning the same PDGF signal, delivered after polynucleotides have improved the environment, encounters a more traversable substrate and produces proportionally better recruitment outcomes. This is the mechanistic basis for the polynucleotides-first sequencing in compromised tissue, and it applies directly to PDGF’s function rather than just the downstream collagen synthesis phase.
Red light therapy: a different mechanism, genuinely complementary
There’s something worth understanding about LED red light therapy that tends to get lost in broad “stimulates collagen” claims: its relationship to PDGF is distinct from everything else in the portfolio, not simply weaker. LED red light modulates fibroblast activity through ROS-mediated changes to PI3K/Akt and MAPK/ERK phosphorylation – downstream signalling pathways that overlap with PDGFR activation but are reached independently of PDGF. [8] At therapeutic doses, the effect is modulatory rather than uniformly proliferative, which is part of why LED therapy shows anti-fibrotic effects in fibrotic conditions alongside pro-regenerative effects in healing tissue. It’s working on the same downstream machinery through a different upstream route. iPRF recruits and proliferates fibroblasts through PDGF; LED modulates their activity through overlapping but independent signalling. This makes the combination genuinely additive rather than redundant.
Exosomes: another delivery vehicle, different cargo profile
Exosomes – particularly from mesenchymal stem cells or dermal papilla cells – carry PDGF as cargo and activate PDGFR on recipient fibroblasts, giving them a genuine PDGF-mediated mechanism alongside their microRNA and other bioactive cargo. [3] Adipose-derived stem cell exosomes have shown fibroblast proliferation stimulation, MMP-1 reduction, and TGF-β upregulation in photoaged skin models – a profile that meaningfully parallels iPRF’s PDGF effects through a vesicle-based route. [2] As exosome treatments become more established in aesthetic medicine, their PDGF component is one active signal among several and understanding it in the context of this entity helps position exosomes relative to iPRF rather than treating them as interchangeable.
The timeline question
Across all these routes, the timeline from PDGF signalling to visible structural change is governed by the same biology: PDGF recruits fibroblasts; TGF-β1 activates them for collagen synthesis; newly synthesised procollagen is processed into fibrils; mature collagen integrates into the ECM. [11] Weeks to months, not because anything is slow, but because that is the biological timescale of tissue remodelling. For clients hoping to see change within days of any of these treatments, the honest framing is that PDGF has initiated a sequence of cellular events whose structural outcomes will emerge gradually. The treatment worked on the day it was done; the evidence of that work arrives on its own schedule.
How Treatments Leverage PDGF
| Treatment | Interaction Type | Mechanism |
|---|---|---|
| iPRF / PRP | Direct Delivery | Provides exogenous, sustained-release PDGF isoforms. |
| RF Microneedling | Endogenous Trigger | Prompts the body to release its own PDGF via platelet activation. |
| Polynucleotides | Environmental Prep | Protects the collagen substrate PDGF-recruited cells need to move. |
| LED Red Light | Signalling Modulator | Optimises the downstream MAPK/ERK pathways PDGF activates. |
References
Colciago A, Celotti F, Casati L, et al. (2009). In Vitro Effects of PDGF Isoforms (AA, BB, AB and CC) on Migration and Proliferation of SaOS-2 Osteoblasts and on Migration of Human Osteoblasts. Int J Biomed Sci, 5(4), 380-9 . PMC3614801
Dal’Forno-Dini T, Birck MS, Rocha M, et al. (2025). Exploring the reality of exosomes in dermatology. An Bras Dermatol, 100(1), 121-130 . doi.org/10.1016/j.abd.2024.09.002
Ku YC, Omer Sulaiman H, Anderson SR, et al. (2023). The Potential Role of Exosomes in Aesthetic Plastic Surgery: A Review of Current Literature. Plast Reconstr Surg Glob Open, 11(6), e5051 . doi.org/10.1097/gox.0000000000005051
Lepistö J, Peltonen J, Vähä-Kreula M, et al. (1995). Platelet-derived growth factor isoforms PDGF-AA, -AB and -BB exert specific effects on collagen gene expression and mitotic activity of cultured human wound fibroblasts. Biochem Biophys Res Commun, 209(2), 393-9 . doi.org/10.1006/bbrc.1995.1516
Li W, Fan J, Chen M, et al. (2004). Mechanism of human dermal fibroblast migration driven by type I collagen and platelet-derived growth factor-BB. Mol Biol Cell, 15(1), 294-309 . doi.org/10.1091/mbc.e03-05-0352
Lynch SE, Huxel ST, Bond R, et al. (2025). Recombinant Pure PDGF Improves Aesthetic Results and Patient Satisfaction Following RF Microneedling: A Prospective, Randomized, Controlled Clinical Trial. J Cosmet Dermatol, 24(9), e70425 . doi.org/10.1111/jocd.70425
Lynch SE, Nixon JC, Colvin RB, et al. (1987). Role of platelet-derived growth factor in wound healing: synergistic effects with other growth factors. Proc Natl Acad Sci U S A, 84(21), 7696-700 . doi.org/10.1073/pnas.84.21.7696
Mamalis A, Siegel D, Jagdeo J (2016). Visible Red Light Emitting Diode Photobiomodulation for Skin Fibrosis: Key Molecular Pathways. Curr Dermatol Rep, 5, 121-128 . doi.org/10.1007/s13671-016-0141-x
Natarelli N, Gahoonia N, Sivamani RK (2023). Integrative and Mechanistic Approach to the Hair Growth Cycle and Hair Loss. J Clin Med, 12(3) . doi.org/10.3390/jcm12030893
Pavlovic V, Ciric M, Jovanovic V, et al. (2016). Platelet Rich Plasma: a short overview of certain bioactive components. Open Med (Wars), 11(1), 242-247 . doi.org/10.1515/med-2016-0048
Pierce GF, Vande Berg J, Rudolph R, et al. (1991). Platelet-derived growth factor-BB and transforming growth factor beta 1 selectively modulate glycosaminoglycans, collagen, and myofibroblasts in excisional wounds. Am J Pathol, 138(3), 629-46 . PMC1886289
Stratman AN, Schwindt AE, Malotte KM, et al. (2010). Endothelial-derived PDGF-BB and HB-EGF coordinately regulate pericyte recruitment during vasculogenic tube assembly and stabilization. Blood, 116(22), 4720-30 . doi.org/10.1182/blood-2010-05-286872
Thapa RK, Margolis DJ, Kiick KL, et al. (2020). Enhanced wound healing via collagen-turnover-driven transfer of PDGF-BB gene in a murine wound model. ACS Appl Bio Mater, 3(6), 3500-3517 . doi.org/10.1021/acsabm.9b01147
Wang X, Yang Y, Zhang Y, et al. (2019). Fluid platelet-rich fibrin stimulates greater dermal skin fibroblast cell migration, proliferation, and collagen synthesis when compared to platelet-rich plasma. J Cosmet Dermatol, 18(6), 2004-2010 . doi.org/10.1111/jocd.12955
Also Known As
- PDGF
Biological Relationships
Biological Interactions
- Stimulates Anagen Evidence: PDGF signalling sustains DPC function required for anagen maintenance; PDGF deficiency causes hair follicle dermal stem cell depletion and disrupted cycling. Chojnacki 2017 PMC5665619; Shin 2024 BBRC.
- Stimulates Collagen Evidence: PDGF+IGF-1 synergistically stimulate connective tissue/collagen deposition via TGF-beta1 cascade (PDGF brings workforce; TGF-beta activates collagen synthesis). PMC1886289 Pierce 1991; PMC2115493 Pierce 1989.
- Stimulates Dermal Papilla Evidence: PDGFR-beta expressed on dermal papilla cells; PDGF activates DPCs through same receptor pathway as pericyte recruitment. Entity text; Chojnacki 2017 PMC5665619; Shin 2024 BBRC 10.1016/j.bbrc.2024.151110.
- Stimulates Fibroblast Evidence: Platelet-Derived Growth Factor (PDGF) acts directly on fibroblasts, stimulating them to proliferate and produce the essential structural components needed for tissue repair and rejuvenation
- Stimulates Hair follicle Evidence: PDGF activates DPCs via PDGFR-beta explaining iPRF effectiveness in hair follicle stimulation; PDGF signalling required for hair follicle dermal stem cell maintenance. PMC9917549; PMC5665619.
- Stimulates Tissue regeneration Evidence: PDGF recruits and mobilises fibroblasts initiating tissue repair cascade; PDGF+IGF-1 produced 2.4-fold connective tissue increase. Lynch 1987 PMC299367; PMC5329835.
- Interacts with Insulin-like growth factor 1 Evidence: PDGF and IGF-1 are synergistic: alone each has modest effect; together produced 2.4-fold connective tissue increase and 95% epidermal thickness increase. Lynch 1987 PNAS PMC299367.
- Interacts with Transforming growth factor beta Evidence: PDGF precedes and induces TGF-beta1 in wound cascade; PDGF recruits fibroblast workforce, TGF-beta1 activates collagen synthesis. PMC2115493; PMC1886289.
- Interacts with Vascular endothelial growth factor Evidence: VEGF-PDGF coordinated angiogenesis: PDGF-BB recruits pericytes to stabilise VEGF-built endothelial tubes. Entity text; PMC2996127.
- Associated disease Androgenetic alopecia Evidence: PDGF deficiency depletes hair follicle dermal stem cells contributing to androgenetic alopecia progression. Chojnacki 2017 PMC5665619.
Influenced By
- this Stimulated by Vascular endothelial growth factor Evidence: VEGF-initiated endothelial tube formation prompts endothelial cells to secrete PDGF-BB for pericyte recruitment; VEGF initiates cascade leading to PDGF-BB production. PMC2996127.
- this Interacts with Vascular endothelial growth factor Evidence: VEGF-PDGF coordinated angiogenesis: VEGF drives endothelial tube formation; PDGF-BB recruits pericytes to stabilise immature vessels. Entity text; PMC2996127.
- this Inhibited by Matrix metalloproteinase Evidence: MMP-degraded ECM provides less permissive substrate for PDGF-driven fibroblast migration via PDGFR-beta; fragmented matrix reduces PDGF recruitment yield. Li et al. 2003 DOI 10.1091/mbc.e03-05-0352.
- this Produced by Platelet Evidence: PDGF (AA, AB, BB isoforms) stored in platelet alpha granules and released upon platelet activation. Entity text; PMC5329835.
- this Produced by Platelet-rich plasma therapy Evidence: iPRF and PRP deliver all three PDGF isoforms from platelet alpha granules; only treatments providing exogenous PDGF. Entity text; PMC5329835.
- this Required by Tissue regeneration Evidence: PDGF is a primary fibroblast chemoattractant and key growth factor in tissue regeneration; PDGF-BB is the only FDA-approved growth factor for diabetic ulcer healing (PMC3663196 Table; PMC7371992).
Learn More
This topic is discussed in 3 articles:
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Discover the detailed science behind PRP and iPRF therapies. Learn how growth factors, platelets, and cellular mechanisms drive hair restoration and skin rejuvenation at a molecular level.
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A family of growth factors stored in platelet alpha granules and released on activation, functioning primarily as a recruitment signal that drives fibroblast migration, proliferation, and angiogenesis