Platelet-derived growth factor--an introduction

Association of arsenic exposure with PDGF-BB in vitro and in a South Texas population exposed through drinking water

Exposure to arsenic (As) from drinking water is a global public health concern, as As is a recognized carcinogen. Groundwater in South Texas, particularly in areas with Gulf Coast aquifers, contains high levels of As. Private wells are neither regulated nor regularly monitored, leaving residents vulnerable to arsenic exposure. This study aimed to investigate potential biomarkers of health effects for long-term, low-level As exposure among private well users in South Texas and to cross-validate findings using an in vitro model. Among 74 private well users, the association between urinary As levels and urinary LDH and 16 cytokine levels was assessed. After adjusting for covariates, linear regression analysis showed weak but significant associations between urinary total inorganic As levels and LDH (β = 0.37, p < 0.01, R2 = 0.23) and PDGF-BB (β = 0.22, p = 0.02, R2 = 0.17). However, no significant associations were found with other cytokines. To compare findings from the population study, SV-HUC-1 uroepithelial cells were exposed to 0.1 or 0.5 μM NaAsO₂ subchronically for 5 weeks, corresponding to total arsenic levels of 7.5 and 37.5 μg/L in drinking water. As exposure was not cytotoxic at either dose, as indicated by lactate dehydrogenase (LDH) activity. However, platelet-derived growth factor (PDGF)-BB protein levels showed a statistically significant increase at a lower concentration of 0.1 μM. These findings suggest that PDGF-BB may serve as a potential biomarker for low-level As exposure, but further studies are required for confirmation.

Prostate Cancer Survivors Present Long-Term, Residual Systemic Immune Alterations

BACKGROUND

The development of cancer and anti-tumor therapies can lead to systemic immune alterations but little is known about how long immune dysfunction persists in cancer survivors.

METHODS

We followed changes in the cellular immune parameters of prostate cancer patients with good prognostic criteria treated with low dose rate brachytherapy before and up to 3 years after the initiation of therapy.

RESULTS

Patients before therapy had a reduced CD4+ T cell pool and increased regulatory T cell fraction and these alterations persisted or got amplified during the 36-month follow-up. A significant decrease in the total NK cell number and a redistribution of the circulating NK cells in favor of a less functional anergic subpopulation was seen in patients before therapy but tumor regression led to the regeneration of the NK cell pool and functional integrity. The fraction of lymphoid DCs was increased in patients both before therapy and throughout the whole follow-up. Increased PDGF-AA, BB, CCL5 and CXCL5 levels were measured in patients before treatment but protein levels rapidly normalized.

CONCLUSIONS

while NK cell dysfunction recovered, long-term, residual alterations persisted in the adaptive and partly in the innate immune system.

Omental adipose tissue is a more suitable source of canine Mesenchymal stem cells

Background

Mesenchymal Stem Cells (MSCs) are a promising therapeutic tool in veterinary medicine. Currently the subcutaneous adipose tissue is the leading source of MSCs in dogs. MSCs derived from distinct fat depots have shown dissimilarities in their accessibility and therapeutic potential. The aims of our work were to determine the suitability of omental adipose tissue as a source of MSCs, according to sampling success, cell yield and paracrine properties of isolated cells, and compared to subcutaneous adipose tissue.

Results

While sampling success of omental adipose tissue was 100% (14 collections from14 donors) for subcutaneous adipose tissue it was 71% (10 collections from 14 donors). MSCs could be isolated from both sources. Cell yield was significantly higher for omental than for subcutaneous adipose tissue (38 ± 1 vs. 30 ± 1 CFU-F/g tissue, p < 0.0001). No differences were observed between sources regarding cell proliferation potential (73 ± 1 vs. 74 ± 1 CDPL) and cell senescence (at passage 10, both cultures presented enlarged cells with cytoplasmic vacuoles and cellular debris). Omental- and subcutaneous-derived MSCs expressed at the same level bFGF, PDGF, HGF, VEGF, ANG1 and IL-10. Irrespective of the source, isolated MSCs induced proliferation, migration and vascularization of target cells, and inhibited the activation of T lymphocytes.

Conclusion

Compared to subcutaneous adipose tissue, omental adipose tissue is a more suitable source of MSCs in dogs. Since it can be procured from donors with any body condition, its collection procedure is always feasible, its cell yield is high and the MSCs isolated from it have desirable differentiation and paracrine potentials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1053-0) contains supplementary material, which is available to authorized users.

Advantages of Autologous Platelet-Rich Fibrin Membrane on Gingival Crevicular Fluid Growth Factor Levels and Periodontal Healing: A Randomized Split-Mouth Clinical Study

BACKGROUND

This study evaluates contributions of platelet-rich fibrin (PRF) combined with conventional flap surgery on growth factor levels in gingival crevicular fluid (GCF) and periodontal healing.

METHODS

Twenty-six patients (52 sites) with chronic periodontitis were treated either with autologous PRF with open flap debridement (OFD+PRF) or OFD alone. Growth factor levels in GCF at baseline and 2, 4, and 6 weeks after surgery were analyzed, and clinical parameters such as probing depth (PD), relative clinical attachment level (rCAL), and gingival margin level (GML) at baseline and 9 months after surgery were measured.

RESULTS

Mean PD reduction and rCAL gain were significantly greater in OFD+PRF sites than in OFD sites. Mean GML change was -0.38 + 0.10 mm in OFD sites and 0.11 + 0.08 mm in the test group; difference between the two groups was statistically significant (P <0.05). Both groups demonstrated increased expression levels of fibroblast growth factor-2, transforming growth factor-β1, and platelet-derived growth factor-BB at 2 weeks compared with baseline, followed by reductions at 4 and 6 weeks. The OFD+PRF group showed significantly higher growth factor levels compared with the OFD group at 2 and 4 weeks.

CONCLUSION

PRF membrane combined with OFD provides significantly higher GCF concentrations of angiogenic biomarkers for ≈2 to 4 weeks and better periodontal healing in terms of conventional flap sites.

Efficacy of growth factor in promoting early osseointegration

A preclinical study was conducted to evaluate the feasibility of 2 different topical formulations of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to promote early osseointegration and enhanced bone-to-implant contact (BIC) for dental implants placed in an edentulous ridge. Six female beagle dogs were divided into 3 groups. The control group included 4 implants with no coating; test group A included 10 implants with commercially available rhPDGF-BB formulation coating; and second test group B included 10 implants with prototype viscous rhPDGF-BB coating. Three dogs were sacrificed at 3 weeks (12 implants) and the remaining 3 dogs at 6 weeks after implant placement (12 implants). The specimens were retrieved for histological evaluation, and revealed an uneventful healing of all implants without any sign of an inflammatory response at the different time intervals. Furthermore, the bone was in very close contact with the implants' surfaces with no evidence of intervening fibrous tissue layers. At 3 weeks, new bone formation between most implant threads on rhPDGF-BB coated implants was evident, whereas in the control group only a thin and sparse amount of new bone was noted. At 6 weeks, the commercially available rhPDGF-BB formulation coated implant group (Group A) showed more trabecular bone and higher BIC compared to the other 2 groups. Histologically, the results in this study showed that use of conventionally available rhPDGF-BB formulation as the implant surface treatment may accelerate the process of osseointegration and enhance BIC.

An in silico exploration of the interaction mechanism of pyrazolo[1,5-a]pyrimidine type CDK2 inhibitors

CDK2, which interacts with cyclin A and cyclin E, is an important member of the CDK family. Having been proved to be associated with many diseases for its vital role in cell cycle, CDK2 is a promising target of anti-cancer drugs dealing with cell cycle disorders. In the present work, a total of 111 pyrazolo[1,5-a]pyrimidines (PHTPPs) as CDK2/cyclin A inhibitors were studied to conduct three-dimensional quantitative structure-activity (3D-QSAR) analyses. The optimal comparative molecular similarity indices analysis (CoMSIA) model shows that Q(2) = 0.516, Rncv(2) = 0.912, Rpre(2) = 0.914, Rm(2) = 0.843, SEP = 0.812, SEE = 0.347 with 10 components using steric, hydrophobic and H-bond donor field descriptors, indicating its effective internal and external predictive capacity. The contour maps further indicate that (1) bulky substituents in R1 are beneficial while H-bond donor groups at this position are detrimental; (2) hydrophobic contributions in the R2 area are favorable; (3) large and hydrophilic groups are well tolerated at the R3 position (a close H-bond donor moiety is favorable while a distal H-bond donor moiety in this area is disfavored); (4) bulky and hydrophobic features in the R4 region are beneficial for the biological activities and (5) the 7-N-aryl substitution is crucial to boost the inhibitory activities of the PHTPP inhibitors. Finally, docking and MD simulations demostrate that PHTPP derivatives are stabilized in a 'flying bat' conformation mainly through the H-bond interactions and hydrophobic contacts. Comparative studies indicate that PHTPP derivatives fit well within the ATP binding cleft in CDK2, with the core heterocyclic ring overlapping significantly with the adenine group of ATP despite a small deflection. In comparison to numerous other inhibitors binding to the ATP pocket, PHTPP analogues follow the binding fashion of purine inhibitors of this kinase. It is anticipated that the binding mechanism and structural features of PHTPP inhibitors studied in the present work will benefit the discovery of more potent CDK2 inhibitors, and the valid pyrazolo[1,5-a]pyrimidine-7-N-yl inhibitors will soon emerge from the large number of screening programmes to enter in clinical studies.

The role of angiogenic factors in fibroid pathogenesis: potential implications for future therapy

BACKGROUND

It is well established that tumors are dependent on angiogenesis for their growth and survival. Although uterine fibroids are known to be benign tumors with reduced vascularization, recent work demonstrates that the vasculature of fibroids is grossly and microscopically abnormal. Accumulating evidence suggests that angiogenic growth factor dysregulation may be implicated in these vascular and other features of fibroid pathophysiology.

METHODS

Literature searches were performed in PubMed and Google Scholar for articles with content related to angiogenic growth factors and myometrium/leiomyoma. The findings are hereby reviewed and discussed.

RESULTS

Multiple growth factors involved in angiogenesis are differentially expressed in leiomyoma compared with myometrium. These include epidermal growth factor (EGF), heparin-binding-EGF, vascular endothelial growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor-β and adrenomedullin. An important paradox is that although leiomyoma tissues are hypoxic, leiomyoma feature down-regulation of key molecular regulators of the hypoxia response. Furthermore, the hypoxic milieu of leiomyoma may contribute to fibroid development and growth. Notably, common treatments for fibroids such as GnRH agonists and uterine artery embolization (UAE) are shown to work at least partly via anti-angiogenic mechanisms.

CONCLUSIONS

Angiogenic growth factors play an important role in mechanisms of fibroid pathophysiology, including abnormal vasculature and fibroid growth and survival. Moreover, the fibroid's abnormal vasculature together with its aberrant hypoxic and angiogenic response may make it especially vulnerable to disruption of its vascular supply, a feature which could be exploited for treatment. Further experimental studies are required in order to gain a better understanding of the growth factors that are involved in normal and pathological myometrial angiogenesis, and to assess the potential of anti-angiogenic treatment strategies for uterine fibroids.

Effect of implantation of Augment(®) Bone Graft on serum concentrations of platelet-derived growth factors: a pharmacokinetic study

BACKGROUND

Augment(®) Bone Graft is a bone graft substitute intended to be used as an alternative to autologous bone graft in the fusion of hindfoot and ankle joints. Augment(®) Bone Graft is a combination device comprised of beta-tricalcium phosphate (β-TCP) and recombinant human platelet-derived growth factor BB homodimer (rhPDGF-BB).

OBJECTIVE

This human pharmacokinetic study was undertaken to assess the effect of Augment(®) Bone Graft implantation on the serum concentration of platelet-derived growth factors (PDGFs).

METHODS

Under the terms of a Research Ethics Board-approved protocol, Augment(®) Bone Graft was implanted in patients (n = 7) undergoing hindfoot and ankle arthrodesis procedures requiring graft material. The control cohort of the study (n = 4) received autologous bone graft. The serum concentrations of PDGF isoforms AA, AB and BB in blood samples, obtained prior to and at ten time points (up to 7 days) after surgery, were measured using enzyme-linked immunosorbent assays (ELISA).

RESULTS

The serum concentration of PDGF-BB did not vary significantly from baseline (median of the combined cohorts 3.89 ng/mL) throughout the course of the study. The serum concentrations of PDGF-AA, PDGF-AB and total PDGF did not deviate from their baseline values (medians of the combined cohorts were 2.87, 14.95 and 20.19 ng/mL for PDGF-AA, PDGF-AB and total PDGF, respectively) except for the last time point in which they were increased (medians for the combined cohorts were 4.71, 20.42 and 30.29 ng/mL for PDGF-AA, PDGF-AB and total PDGF, respectively). There were no differences between the two treatment groups with regard to changes in the serum concentrations of PDGF. None of the samples tested contained anti-PDGF-BB antibodies.

CONCLUSION

Analysis of the data demonstrated that the serum concentrations of all three PDGF isoforms analysed were unaffected by implantation of Augment(®) Bone Graft.

Safety of recombinant human platelet-derived growth factor-BB in Augment(®) Bone Graft

This article discusses nonclinical and clinical data regarding the safety of recombinant human platelet-derived growth factor-BB as a component of the Augment(®) Bone Graft (Augment). Augment is a bone graft substitute intended to be used as an alternative to autologous bone graft in the fusion of hindfoot and ankle joints. Nonclinical studies included assessment of the pharmacokinetic profile of intravenously administered recombinant human platelet-derived growth factor-BB in rat and dog, effects of intravenous administration of recombinant human platelet-derived growth factor-BB in a reproductive and development toxicity study in rats, and chronic toxicity and carcinogenicity of Augment in a 12-month implantation model. These studies showed that systemic exposure was brief and clearance was rapid. No signs of toxicity, carcinogenicity, or tumor promotion were observed even with doses far exceeding the maximum clinical dose. Results of clinical trials (605 participants) and commercial use of recombinant human platelet-derived growth factor-BB containing products indicate that these products are not associated with increased incidence of adverse events or cancer. The safety data presented provide evidence that recombinant human platelet-derived growth factor-BB is a safe therapeutic when used in combination products as a single administration during surgical procedures for bone repair and fusion. There is no evidence associating use of recombinant human platelet-derived growth factor-BB in Augment with chronic toxicity, carcinogenicity, or tumor promotion.

The combination of purified recombinant human platelet-derived growth factor-BB and equine particulate bone graft for periodontal regeneration

BACKGROUND

The objective of this study is to evaluate the potential for periodontal regeneration of a critical-sized defect with the application of recombinant human platelet-derived growth factor (rhPDGF-BB) combined with either a particulate equine or a β-tricalcium phosphate (β-TCP) matrix.

METHODS

Critical-sized intrabony 2-wall defects were created bilaterally on the distal surface of the second premolar and the mesial surface of the first molar in nine hounds. Twelve defects received rhPDGF-BB/equine treatment, 12 defects received rhPDGF-BB/β-TCP treatment, and the remaining 12 sites served as sham-surgery controls. The animals were sacrificed after a 10-week healing period.

RESULTS

Clinical healing was uneventful without obvious signs of overt gingival inflammation. Histologic and histomorphometric analyses revealed statistically that there were differences among the three groups in terms of new bone formation (P <0.001). The amount of test material for both rhPDGF-BB/equine and rhPDGF-BB/β-TCP groups was comparable, but the amount of newly formed bone was significantly higher (P <0.01) in favor of the rhPDGF-BB/equine group. The amount of new cementum formed for the rhPDGF-BB/equine group (4.8 ± 1.3 mm) was significantly higher (P =0.001) than the sham-surgery control group (1.7 ± 1.9 mm).

CONCLUSION

Both rhPDGF-BB/equine and rhPDGF-BB/β-TCP have the potential to support the regeneration of the periodontal attachment apparatus.

Potential roles of growth factor PDGF-BB in the bony repair of injured growth plate

Injured growth plate cartilage is often repaired by bony tissue resulting in impaired bone growth in children. Using a rat injury model, our previous studies show that following the injury-induced initial inflammatory response, an influx of mesenchymal-like cells occurs within the growth plate injury site prior to formation of bony tissue. As platelet-derived growth factor (PDGF-BB) is a potent chemotactic factor of mesenchymal cells during skeletal tissue repair, we examined its role during the early fibrogenic response and the subsequent bony repair of injured growth plate. Following growth plate injury, rats received daily injection of the PDGF receptor (PDGFR) inhibitor, Imatinib, for 7 days. Immunohistochemical analysis of injured growth plate at day 1 showed the presence of PDGF-BB expression in some inflammatory cells, while at day 4 PDGFR was expressed by a proportion of the infiltrating mesenchymal cells at the injury site. By day 4, PDGFR inhibition reduced mesenchymal infiltrate (P<0.05); by day 14, Imatinib-treated rats exhibited less bony trabeculae and cartilaginous repair tissues, fewer osteoclasts and less bone marrow (BM) at the injury site, compared to vehicle controls (P<0.01). In vitro "scratch" migration assays with rat BM mesenchymal cells revealed that recombinant PDGF-BB increased cell migration into the "wound" (P<0.05), while Imatinib inhibited this chemotactic response. Quantitative RT-PCR analysis showed that Imatinib treatment decreased expression of the cartilage and bone related genes, Col2a1 and osteocalcin, respectively. These results suggest that PDGF-BB contributes to growth plate injury repair by promoting mesenchymal progenitor cell infiltration, the chondrogenic and osteogenic responses, and remodelling of the repair tissues.

Guided tissue regeneration may modulate gene expression in periodontal intrabony defects: a human study

BACKGROUND AND OBJECTIVE

Guided tissue regeneration has been shown to lead to periodontal regeneration, however, the mechanisms involved remain to be clarified. The present study was carried out to assess the expression of genes involved in the healing process of periodontal tissues in membrane-protected vs. nonprotected intrabony defects in humans.

MATERIAL AND METHODS

Thirty patients with deep intrabony defects (> or = 5 mm, two or three walls) around teeth that were scheduled for extraction were selected and randomly assigned to receive one of the following treatments: flap surgery alone (control group) or flap surgery plus guided tissue regeneration (expanded polytetrafluorethylene (e-PTFE) membrane) (test group). Twenty-one days later, the newly formed tissue was harvested and quantitatively assessed using the polymerase chain reaction assay for the expression of the following genes: alkaline phosphatase, receptor activator of nuclear factor-kappa B ligand, osteoprotegerin, osteopontin, osteocalcin, bone sialoprotein, basic fibroblast growth factor, interleukin-1, interleukin-4, interleukin-6, matrix metalloproteinase-2 and matrix metalloproteinase-9.

RESULTS

Data analysis demonstrated that mRNA levels for alkaline phosphatase, receptor activator of nuclear factor-kappa B ligand, osteoprotegerin, osteopontin, bone sialoprotein, basic fibroblast growth factor, interleukin-1, interleukin-6, matrix metalloproteinase-2 and matrix metalloproteinase -9 were higher in the sites where guided tissue regeneration was applied compared with the control sites (p < 0.05), whereas osteocalcin mRNA levels were lower (p < 0.05). No difference was observed in interleukin-4 mRNA levels between control and test groups.

CONCLUSION

Within the limits of this study, it can be concluded that genes are differentially expressed in membrane barrier-led periodontal healing when compared with flap surgery alone, and this may account for the clinical outcome achieved by guided tissue regeneration.

Effects of platelet-derived growth factor isoforms on plasminogen activation by periodontal ligament and gingival fibroblasts

BACKGROUND AND OBJECTIVE

Platelet-derived growth factor isoforms and components of the plasminogen activator system are expressed at higher levels during periodontal regeneration. Recombinant platelet-derived growth factor-BB is approved for the treatment of periodontal defects. In the present study we investigated the effect of platelet-derived growth factor isoforms on the plasminogen activator system in periodontal fibroblasts.

MATERIAL AND METHODS

Human periodontal ligament fibroblasts and gingival fibroblasts were exposed to platelet-derived growth factor isoforms. Changes in urokinase-type plasminogen activator, tissue-type plasminogen activator, plasminogen activator inhibitor-1 and plasminogen activator inhibitor-2 transcript levels by platelet-derived growth factor-BB were monitored with a quantitative reverse transcription-polymerase chain reaction. Urokinase-type plasminogen activator and plasminogen activator inhibitor-1 protein levels were assessed by immunoassays. The effects of platelet-derived growth factor-BB on mitogen-activated protein kinase and phosphoinositol-3 kinase/Akt signaling were investigated by western blot and inhibitor studies. Casein zymography and kinetic assays revealed the size and activity, respectively, of the plasminogen activators.

RESULTS

We found that incubation of periodontal ligament fibroblasts and gingival fibroblasts with platelet-derived growth factor-BB resulted in enhanced levels of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 transcripts, but not of tissue-type plasminogen activator and plasminogen activator inhibitor-2. Platelet-derived growth factor-BB also increased urokinase-type plasminogen activator and plasminogen activator inhibitor-1 release into the culture medium. Phosphorylation of extracellular signal-regulated kinase, p38, c-Jun N-terminal kinase and Akt was observed in fibroblasts of both origin. Inhibition of phosphoinositol-3 kinase signaling abrogated the platelet-derived growth factor-BB effect on plasminogen activator inhibitor-1 production. Casein zymography revealed enzymatic activity of the urokinase-type plasminogen activator in cell-conditioned media and lysates of periodontal ligament fibroblasts and gingival fibroblasts. Exposure of gingival fibroblasts, but not of periodontal ligament fibroblasts, to platelet-derived growth factor isoforms moderately increased total plasminogen activation in the medium.

CONCLUSION

These findings suggest that periodontal ligament fibroblasts attempt to maintain an equilibrium of the plasminogen activator system in the presence of platelet-derived growth factor isoforms.

Influence of aging on biological properties of periodontal ligament cells

The majority of patients eligible for periodontal regenerative therapies are aged subjects. Since periodontal ligament cells (PDLC) are essential for periodontal regeneration, the aim of the present study was to determine the effect of cellular aging on PDLC, including genes associated with extracellular matrix metabolism and growth-associated factors. PDLC cultures were obtained from subjects aged 15 to 20 years and subjects aged more than 60 years. Proliferation, cell viability, mineralization assays, and mRNA levels were assessed for type I and III collagen, platelet-derived growth factor (PDGF)-1, basic fibroblast growth factor (bFGF), metalloproteinase (MMP)-2 and-8, and tissue inhibitor of metalloproteinases (TIMP)-1 and-2. Data analysis demonstrated that aging negatively influenced cell proliferation and mineral nodule formation (p < 0.05). Gene expression analysis further showed that mRNA levels for bFGF, PDGF-1, and TIMP-2 were not affected by aging (p > 0.05). In addition, mRNA levels for type I and III collagen were significantly lower in aged cells (p < 0.05), whereas MMP-2 and-8 and TIMP-1 mRNA levels were higher (p < 0.05). Within the limits of the present study, data analysis suggests that aging modulates important biological properties of periodontal ligament cells, diminishes the potential for mineral nodule formation, and favors extracellular matrix degradation.

Chondrocyte signaling and artificial matrices for articular cartilage engineering

Chondrocytes depend on their environment to aid in their expression of appropriate proteins. It has been found that the interaction of integrin receptors with chondrocytes effects the production of extracellular molecules such as type II collagen and aggrecan. Additionally, the presence of growth factors such as IGF-1, TGF-beta1 and BMP-7 induce various signaling pathways that also aid in transducing phenotypic expressions by chondrocytes. Natural and synthetic polymers have been used to act as a scaffold for chondrocytes. The production of extracellular matrix proteins by chondrocytes has been studied. As tissue engineers, it is advantageous to explore the possibility of how altering biomaterial properties affect the signaling cascades by activation of receptors and transduction through the cytoplasm. This vital information will be able to aid in the future of engineering an appropriate biomaterial that can incorporate chondrocytes to act as a scaffold for articular cartilage.

Effect of rhPDGF-BB delivery on mediators of periodontal wound repair

Growth factors such as platelet-derived growth factor (PDGF) exert potent effects on wound healing including the regeneration of tooth-supporting structures. This investigation examined the effect of the local delivery of PDGF-BB when combined with reconstructive periodontal surgery on local wound fluid (WF) levels of PDGF-AB, vascular endothelial growth factor (VEGF), and bone collagen telopeptide (ICTP) in humans with advanced periodontitis. Sixteen patients exhibiting localized periodontal osseous defects were randomized to one of three groups (beta-TCP carrier alone, beta-TCP + 0.3 mg/mL of recombinant human PDGF-BB [rhPDGF-BB], or beta-TCP + 1.0 mg/mL of rhPDGF-BB) and monitored for 6 months. WF was harvested and analyzed for PDGF-AB, VEGF, and ICTP WF levels. Teeth contralateral to the target lesions served as controls. Increased levels of VEGF in the WF was observed for all surgical treatment groups with the 1.0 mg/mL rhPDGF-BB group showing the most pronounced difference at 3 weeks in the AUC analysis versus control (p < 0.0001). PDGF-AB WF levels were increased for the carrier alone group compared to both rhPDGFBB groups. Low-dose rhPDGF-BB application elicited increases in ICTP at days 3-5 in the wound healing process, suggesting a promotion of bone turnover at early stages of the repair process (p < 0.02). These results demonstrate contrasting inducible expression patterns of PDGF-AB, VEGF, and ICTP during periodontal wound healing in humans.