Platelet-rich plasma, plasma rich in growth factors and simvastatin in the regeneration and repair of alveolar bone

Progress on the application of growth factor-related drugs in ophthalmology

Vascular endothelial growth factor（VEGF）, fibroblast growth factor（FGF）, nerve growth factor（NGF）, epidermal growth factor and interferon are important endogenous proteins that regulate cell proliferation, differentiation and regeneration. Biological products targeting growth factors are used in the treatment of ocular diseases such as wet age-related macular degeneration, corneal injury and neurotrophic keratitis. Anti-VEGF drugs can regulate the proliferation of vascular endothelia, reduce the edema and exudation of retinal tissue，which are the main therapeutic agents for wet age-related macular degeneration and diabetic retinopathy. The basic FGF (b-FGF) can promote the proliferation, differentiation, and migration of corneal epithelial cells, accelerating the healing of the corneal injury and reduces corneal inflammation；and bovine b-FGF has been approved for the treatment of corneal injuries. The NGF promotes the growth, development, and differentiation of central and peripheral neurons, thus accelerating the repair of nerve damage；and the European Medicines Agency approved the use of nerve growth factor for the treatment of neurotrophic keratitis in 2017. Recent clinical studies show that patients with moderate or severe neurotrophic keratitis achieved complete corneal healing following 8 weeks of NGF therapy. Epidermal growth factor derivative eye drops have been approved for the treatment of corneal epithelial injuries. Recombinant human interferon has been clinically used in the treatment of ocular viral infections. This article reviews the research progress in the development of new cell growth factor drugs for the treatment of ophthalmic diseases, to provide insights for expanding the application of cell growth factors in ophthalmology.

Tissue engineering in periodontology: Biological mediators for periodontal regeneration

Teeth and the periodontal tissues represent a highly specialized functional system. When periodontal disease occurs, the periodontal complex, composed by alveolar bone, root cementum, periodontal ligament, and gingiva, can be lost. Periodontal regenerative medicine aims at recovering damaged periodontal tissues and their functions by different means, including the interaction of bioactive molecules, cells, and scaffolds. The application of growth factors, in particular, into periodontal defects has shown encouraging effects, driving the wound healing toward the full, multi-tissue periodontal regeneration, in a precise temporal and spatial order. The aim of the present comprehensive review is to update the state of the art concerning tissue engineering in periodontology, focusing on biological mediators and gene therapy.

Simvastatin With PRP Promotes Chondrogenesis of Bone Marrow Stem Cells In Vitro and Wounded Rat Achilles Tendon-Bone Interface Healing In Vivo

BACKGROUND

Tendons and ligaments are joined to bone in a specialized interface that transmits force from muscle to bone and permits body movement. Tendon/ligament injuries always occur in the interface areas, and injured tendons/ligaments have a limited healing response because the insertion site is composed of a fibrocartilaginous zone.

PURPOSE

To study the effect of simvastatin with platelet-rich plasma (PRP) on chondrogenesis of rat bone marrow stem cells (BMSCs) in vitro and wounded rat Achilles tendon-bone interface healing in vivo.

STUDY DESIGN

Controlled laboratory study.

METHODS

The in vitro model was performed by the culture of rat BMSCs with various concentrations of simvastatin (0, 10, 50, 100 nM) for 2 weeks. The effect of simvastatin on the chondrogenic differentiation of the BMSCs was examined by histochemical analysis and real-time quantitative reverse transcription polymerase chain reaction. The in vivo model was carried out by testing the healing effect of simvastatin with PRP on 12 wounded rat Achilles tendon-bone interfaces.

RESULTS

Simvastatin induced chondrogenic differentiation of rat BMSCs in a concentration-dependent manner as evidenced by histological staining and real-time quantitative reverse transcription polymerase chain reaction. The wounds treated with simvastatin alone or with simvastatin-containing PRP gel healed much faster than the wounds treated with saline alone or PRP alone. Histological analysis showed that higher percentages of healed tissues were positively stained with safranin O and fast green in wounds treated with simvastatin-containing PRP gel than in the other 3 groups. Immunohistochemical analysis further demonstrated these findings, as evidenced by more positively stained healed tissues with collagen I and II antibodies in the wound areas treated with simvastatin-containing PRP gel than the other 3 groups.

CONCLUSION

The combination of simvastatin with PRP induced chondrogenesis of BMSCs in vitro and enhanced fibrocartilage formation in vivo. The simvastatin-PRP gel treatment promotes wounded tendon-bone interface healing in clinical treatment.

CLINICAL RELEVANCE

The combination of simvastatin with PRP may be a good clinical treatment for wounded tendon/ligament junction healing, especially for acute sports-related tendon/ligament injuries.

Role of Simvastatin on fracture healing and osteoporosis: a systematic review on in vivo investigations

Simvastatin is a lipid lowering drug whose beneficial role on bone metabolism was discovered in 1999. Several in vivo studies evaluated its role on osteoporosis and fracture healing, however, controversial results are seen in the literature. For this reason, Simvastatin has not been the focus of any clinical trials as yet. This systematic review clears the mechanisms of action of Simvastatin on bone metabolism and focuses on in vivo investigations that have evaluated its role on osteoporosis and fracture repair to find out (i) whether Simvastatin is effective on treatment of osteoporosis and fracture repair, and (ii) which of the many available protocols may have the ability to be translated in the clinical setting. Simvastatin induces osteoinduction by increasing osteoblast activity and differentiation and inhibiting their apoptosis. It also reduces osteoclastogenesis by decreasing both the number and activity of osteoclasts and their differentiation. Controversial results between the in vivo studies are mostly due to the differences in the route of administration, dose, dosage and carrier type. Local delivery of Simvastatin through controlled drug delivery systems with much lower doses and dosages than the systemic route seems to be the most valuable option in fracture healing. However, systemic delivery of Simvastatin with much higher doses and dosages than the clinical ones seems to be effective in managing osteoporosis. Simvastatin, in a particular range of doses and dosages, may be beneficial in managing osteoporosis and fracture injuries. This review showed that Simvastatin is effective in the treatment of osteoporosis and fracture healing.

Dental pulp stem cells as a multifaceted tool for bioengineering and the regeneration of craniomaxillofacial tissues

Dental pulp stem cells, or DPSC, are neural crest-derived cells with an outstanding capacity to differentiate along multiple cell lineages of interest for cell therapy. In particular, highly efficient osteo/dentinogenic differentiation of DPSC can be achieved using simple in vitro protocols, making these cells a very attractive and promising tool for the future treatment of dental and periodontal diseases. Among craniomaxillofacial organs, the tooth and salivary gland are two such cases in which complete regeneration by tissue engineering using DPSC appears to be possible, as research over the last decade has made substantial progress in experimental models of partial or total regeneration of both organs, by cell recombination technology. Moreover, DPSC seem to be a particularly good choice for the regeneration of nerve tissues, including injured or transected cranial nerves. In this context, the oral cavity appears to be an excellent testing ground for new regenerative therapies using DPSC. However, many issues and challenges need yet to be addressed before these cells can be employed in clinical therapy. In this review, we point out some important aspects on the biology of DPSC with regard to their use for the reconstruction of different craniomaxillofacial tissues and organs, with special emphasis on cranial bones, nerves, teeth, and salivary glands. We suggest new ideas and strategies to fully exploit the capacities of DPSC for bioengineering of the aforementioned tissues.

Influence of Leukocyte- and Platelet-Rich Fibrin (L-PRF) in the Healing of Simple Postextraction Sockets: A Split-Mouth Study

The aim of this study was to evaluate the effects of leukocyte- and platelet-rich fibrin (L-PRF) on the pain and soft tissue healing after tooth extractions. Twenty-six patients (9 males and 17 females) were treated with multiple extractions (2 to 8), with a total of 108 extractions. This was an exploratory single blinded randomized clinical trial with a split-mouth design. The pain after the surgery was assessed in each patient by the VAS scale (1 to 10) at intervals of 24-48-72-96 hours. The soft tissue healing was clinically evaluated at 3, 7, 14, and 21 days after surgery by the same examiner surgeon, using the modified Healing Index (4 to 12). The mean value of postextraction pain was 3.2 ± 0.3 in the experimental sides and 4.1 ± 0.1 in the control sides. After 7 days from the extractions, the values of modified Healing Index in the experimental and control groups were, respectively, 4.8 ± 0.6 and 5.1 ± 0.9. The use of L-PRF in postextraction sockets filling can be proposed as a useful procedure in order to manage the postoperative pain and to promote the soft tissue healing process, reducing the early adverse effects of the inflammation.

Platelet-rich plasma in bone regeneration: engineering the delivery for improved clinical efficacy

Human bone is a tissue with a fairly remarkable inherent capacity for regeneration; however, this regenerative capacity has its limitations, and defects larger than a critical size lack the ability to spontaneously heal. As such, the development and clinical translation of effective bone regeneration modalities are paramount. One regenerative medicine approach that is beginning to gain momentum in the clinical setting is the use of platelet-rich plasma (PRP). PRP therapy is essentially a method for concentrating platelets and their intrinsic growth factors to stimulate and accelerate a healing response. While PRP has shown some efficacy in both in vitro and in vivo scenarios, to date its use and delivery have not been optimized for bone regeneration. Issues remain with the effective delivery of the platelet-derived growth factors to a localized site of injury, the activation and temporal release of the growth factors, and the rate of growth factor clearance. This review will briefly describe the physiological principles behind PRP use and then discuss how engineering its method of delivery may ultimately impact its ability to successfully translate to widespread clinical use.