Platelets, as cell fragments from bone marrow megakaryocytes, are characterized by the absence of nuclei. Each platelet contains three kinds of particles, namely α Granules, dense bodies and lysosomes with different quantities. Including α The granules are rich in more than 300 different proteins, such as vascular endothelial activating factor, leukocyte chemotactic factor, activating factor, tissue repair related growth factor and antibacterial peptide, which are involved in many physiological and pathological processes, such as wound healing, angiogenesis and anti infection immunity.
The dense body contains high concentrations of adenosine diphosphate (ADP), adenosine triphosphate (ATP), Ca2+, Mg2+and 5-hydroxytryptamine. Lysosomes contain a variety of sugar proteases, such as glycosidases, proteases, cationic proteins and proteins with bactericidal activity. These GF are released into the blood after platelet activation.
GF triggers cascade reaction by binding with different types of cell membrane receptors, and activates specific functions in the process of tissue regeneration. Currently, the most studied GF is platelet derived growth factor (PDGF) and transforming growth factor (TGF- β （TGF- β）， Vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), fibroblast growth factor (FGF), connective tissue growth factor (CTGF) and insulin-like growth factor-1 (IGF-1). These GFs help repair muscle, tendon, ligament and other tissues by promoting cell proliferation and differentiation, angiogenesis and other processes, and then play a corresponding role.
Application of PRP in Vitiligo
Vitiligo, as a common autoimmune disease, as well as a volume impaired skin disease, has a negative impact on the psychology of patients and seriously affected the quality of life of patients. To sum up, the occurrence of vitiligo is the result of the interaction of genetic factors and environmental factors, which causes skin melanocytes to be attacked and damaged by the autoimmune system. At present, although there are many treatments for vitiligo, their efficacy is often poor, and many treatments lack evidence of evidence-based medicine. In recent years, with the continuous exploration of the pathogenesis of vitiligo, some new treatment methods have been constantly applied. As an effective method to treat vitiligo, PRP has been continuously applied.
At present, 308 nm excimer laser and 311 nm narrow band ultraviolet (NB-UVB) and other phototherapy technologies are increasingly recognized for their efficacy in patients with vitiligo. At present, the use of autologous PRP subcutaneous microneedle injection combined with phototherapy in patients with stable vitiligo has made great progress. Abdelghani et al. found in their research that autologous PRP subcutaneous microneedle injection combined with NB-UVB phototherapy can significantly shorten the total treatment time of vitiligo patients.
Khattab et al. treated patients with stable non segmental vitiligo with 308 nm excimer laser and PRP, and achieved good results. It was found that the combination of the two can effectively improve the leucoplakia recolor rate, shorten the treatment time, and avoid the adverse reaction of long-term use of 308 nm excimer laser irradiation. These studies suggest that PRP combined with phototherapy is an effective method for the treatment of vitiligo.
However, Ibrahim and other studies also suggest that PRP alone is not effective in the treatment of vitiligo. Kadry et al. conducted a randomized controlled study on the treatment of vitiligo with PRP combined with carbon dioxide dot matrix laser, and found that PRP combined with carbon dioxide dot matrix laser and PRP alone had achieved good color reproduction effect. Among them, PRP combined with carbon dioxide dot matrix laser had the best color reproduction effect, and PRP alone had achieved moderate color reproduction in the leukoplakia. The color reproduction effect of PRP alone was better than that of carbon dioxide dot matrix laser alone in the treatment of vitiligo.
Operation Combined with PRP in the Treatment of Vitiligo
Vitiligo is a kind of pigment disorder disease characterized by depigmentation. Conventional treatment methods include drug therapy, phototherapy or surgery, or combination of multiple treatment methods. For patients with stable vitiligo and poor effect of conventional treatment, surgical treatment can be the first intervention.
Garg et al. used PRP as the suspension agent of epidermal cells, and used Er: YAG laser to grind the white spots, which achieved good therapeutic effect in the treatment of stable vitiligo patients. In this study, 10 patients with stable vitiligo were enrolled and 20 lesions were obtained. In 20 lesions, 12 lesions (60%) showed complete pigment recovery, 2 lesions (10%) showed large pigment recovery, 4 lesions (20%) showed moderate pigment recovery, and 2 lesions (10%) showed no significant improvement. The recovery of legs, knee joints, face and neck is most obvious, while the recovery of extremities is poor.
Nimitha et al. used PRP suspension of epidermal cells to prepare suspension and phosphate buffer suspension of epidermal cells to compare and observe their pigment recovery in patients with stable vitiligo. 21 stable vitiligo patients were included and 42 white spots were obtained. The average stable time of vitiligo was 4.5 years. Most patients showed small round to oval discrete pigment recovery about 1-3 months after treatment. During 6 months of follow-up, the mean pigment recovery was 75.6% in PRP group and 65% in non PRP group. The difference of pigment recovery area between PRP group and non PRP group was statistically significant. PRP group showed better pigment recovery. When analyzing pigment recovery rate in patients with segmental vitiligo, there was no significant difference between PRP group and non PRP group.
Application of PRP in Chloasma
Melasma is a kind of acquired pigmented skin disease of the face, which mainly occurs on the face of women who are frequently exposed to ultraviolet light and have deep skin color. Its pathogenesis has not been fully clarified, and it is difficult to treat and easy to recur. At present, the treatment of chloasma mostly adopts the combined treatment method. Although the subcutaneous injection of PRP has a variety of treatment methods for chloasma, the efficacy of patients is not very satisfactory, and it is easy to relapse after stopping the treatment. And oral drugs such as tranexamic acid and glutathione may cause abdominal distension, menstrual cycle disorder, headache, and even the formation of deep vein thrombosis.
To explore a new treatment for chloasma is an important direction in the research of chloasma. It is reported that PRP can significantly improve the skin lesions of patients with melasma. Cay ı rl ı Et al. reported that a 27 year old female received subcutaneous microneedle injection of PRP every 15 days. At the end of the third PRP treatment, it was observed that the area of epidermal pigment recovery was>80%, and there was no recurrence within 6 months. Sirithanabadeekul et al. used PRP for the treatment of chloasma to perform more rigorous RCT, which further confirmed the effectiveness of intracutaneous PRP injection for the treatment of chloasma.
Hofny et al. used immunohistochemical method to conduct TGF through subcutaneous microneedle injection of PRP into the skin lesions of patients with chloasma and normal parts- β The comparison of protein expression showed that before PRP treatment, the skin lesions of patients with chloasma and TGF around the skin lesions- β The protein expression was significantly lower than that of healthy skin (P<0.05). After PRP treatment, TGF of skin lesions in patients with chloasma- β The protein expression was increased significantly. This phenomenon indicates that the improvement effect of PRP on chloasma patients may be achieved by increasing the TGF of the skin lesions- β The protein expression achieves the therapeutic effect on chloasma.
Photoelectric Technology Combined with Subcutaneous Injection of PRP for Treatment of Chloasma
With the continuous development of photoelectric technology, its role in the treatment of chloasma has attracted more and more attention of researchers. At present, the lasers used to treat chloasma include Q-switched laser, lattice laser, intense pulsed light, cuprous bromide laser and other treatment measures. The principle is that selective light blasting is carried out for melanin particles within or between melanocytes through energy selection, and the function of melanocytes is inactivated or inhibited through low energy and multiple light blasting, and at the same time, multiple light blasting of melanin particles is carried out, It can make melanin particles smaller and more conducive to being swallowed and excreted by the body.
Su Bifeng et al. treated chloasma with PRP water light injection combined with Q switched Nd: YAG 1064nm laser. Among the 100 patients with chloasma, 15 patients in the PRP+laser group were basically cured, 22 patients were significantly improved, 11 patients were improved, and 1 patient was ineffective; In the laser group alone, 8 cases were basically cured, 21 cases were markedly effective, 18 cases were improved, and 3 cases were ineffective. The difference between the two groups was statistically significant (P<0.05). Peng Guokai and Song Jiquan further verified the effectiveness of Q-switched laser combined with PRP in the treatment of facial chloasma. The results showed that Q-switched laser combined with PRP was effective in the treatment of facial chloasma
According to the current research on PRP in pigmented dermatoses, the possible mechanism of PRP in the treatment of chloasma is that PRP increases the TGF of skin lesions- β The protein expression can improve the melasma patients. The improvement of PRP on vitiligo patients’ skin lesions may be related to the α Adhesion molecules secreted by granules are related to the improvement of local microenvironment of vitiligo lesions by cytokines. The onset of vitiligo is closely related to the abnormal immunity of the skin lesions. Studies have found that the local immune abnormalities of vitiligo patients are related to the failure of keratinocytes and melanocytes in the skin lesions to resist the damage of melanocytes caused by a variety of inflammatory factors and chemokines released in the process of intracellular oxidative stress. However, a variety of platelet growth factors secreted by PRP and a variety of anti-inflammatory cytokines released by platelets, such as soluble tumor necrosis factor receptor I, IL-4 and IL-10, which are antagonists of interleukin-1 receptor, may play a certain role in regulating the local immune balance of skin lesions.
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Post time: Nov-24-2022