Application of platelet exosomes in the preparation of drugs for improving skin conditions

Abstract

The present invention discloses the use of platelet exosomes in the preparation of a drug for improving skin conditions. The present invention also discloses platelet exosomes, a pharmaceutical composition containing the platelet exosomes, and their use in the preparation of skin care products or cosmetics. The platelet exosomes described herein can promote the proliferation of human fibroblasts, thereby promoting collagen secretion, increasing skin thickness, and reducing wrinkles. They can also reduce cell senescence caused by UV damage, significantly reducing the proportion of senescent cells. This invention fills a gap in the application of platelet exosomes in delaying skin aging and has great application prospects in the medical and cosmetic industries.

Description

Technical Field

[0001] The present invention belongs to the medical cosmetology industry and relates to the application of human platelet exosomes, specifically to the application of platelet exosomes in the preparation of drugs for improving skin conditions. Background Art

[0002] Platelets are anucleate cells that are produced by the cytoplasmic lysis of mature megakaryocytes in the bone marrow and then enter the blood circulation to form mature platelets. They play an important role in biomedicine, especially in hemostasis, thrombosis, inflammation, and blood coagulation [1]. In recent years, with the in-depth understanding of platelet function, researchers have found that after activation, platelets release intracellular growth factors, cytokines, and extracellular matrix regulators. These factors can be released in a more abundant form in extracellular vesicles (EVs). EVs are nanoscale lipid membrane-bound particles that transfer proteins, lipids, and nucleic acids from parent cells to recipient cells. Almost every cell type in the human body, including platelets, releases EVs as a medium for intercellular signaling. Platelet-rich plasma exosomes (PRP-Exos) are one of them, which can transport a large amount of growth factors, mRNA, and micro-RNA while protecting their components from damage by degradative chemicals or enzymes. Due to their stability and non-immunogenicity, they can transfer their cargo to target cells to control intercellular signaling, thereby affecting their function. During the inflammatory phase, PRP-Exos have been shown to modulate immune cells and tissue cells, leading to a reduction in inflammatory responses.

[0003] However, whether platelet exosomes can promote fibroblast proliferation and skin repair, thereby exerting anti-aging effects, remains to be studied. Summary of the Invention

[0004] To address the lack of a more effective drug for improving skin conditions in the prior art, the present invention provides the use of platelet exosomes in the preparation of a drug for improving skin conditions. This discovery of a novel function of platelet exosomes, promoting fibroblast proliferation, reveals that platelet exosomes can delay skin aging, filling a gap in the research on platelet exosomes in this area and holds great promise for application in the medical and cosmetic industries.

[0005] To solve the above technical problems, one of the technical solutions provided by the present invention is: a use of platelet exosomes in the preparation of a medicine or pharmaceutical composition for improving skin conditions; the pharmaceutical composition further comprises a pharmaceutically acceptable carrier and / or excipient; wherein the platelet exosomes are separated from platelets produced by activation of megakaryocytes differentiated from iPSCs; the separation is to collect the supernatant in the platelet preparation process, collect the precipitate after centrifugation, and the precipitate is the platelet exosomes; the activation is to treat the megakaryocytes with thrombopoietin, ROCK inhibitor and plasma.

[0006] In this invention, platelet exosomes refer to exosomes isolated from purified platelets. They contain only platelet components and do not contain other cells or components found in whole blood. They are extracted from purified platelet samples using specific separation techniques to ensure their purity and specificity. Platelet-Rich Plasma Exosomes (PRP-Exos) refer to exosomes isolated from platelet-rich plasma (PRP). Because PRP is obtained from whole blood through centrifugation and other methods, PRP-Exos may also contain other components found in whole blood, such as red blood cells, white blood cells, and plasma proteins. Therefore, PRP-Exos include not only platelet exosomes but also exosomes from other blood components.

[0007] According to common knowledge in this field, these two types of exosomes may exhibit different biological activities and therapeutic effects due to their different sources and components.

[0008] In the present invention, an "activator" refers to an agent used to stimulate platelets and induce them to release specific bioactive substances (such as growth factors and cytokines). Typical activators in the art include calcium sodium gluconate and thrombin. The platelets of the present invention are not treated with an activator, and the resulting platelets are in a stable state.

[0009] It is known in the art that platelets differentiated from megakaryocytes using different methods will have different physical and chemical properties, and whether or not activators are used will also affect the active substances released by platelets, and thus the platelet exosomes prepared therefrom will also be different.

[0010] In a specific embodiment of the present invention, the platelet exosomes satisfy one or more conditions selected from the following:

[0011] (1) The main peak particle size is 120-125 nm;

[0012] (2) an average particle size of 135-140 nm; and

[0013] (3) The protein concentration of the platelet exosomes is 6-7 mg / mL.

[0014] In a specific embodiment of the present invention, the centrifugation method is differential ultracentrifugation.

[0015] In a specific embodiment of the present invention, the ROCK inhibitor is Y-27632.

[0016] In a specific embodiment of the invention, said plasma is human plasma.

[0017] In a specific embodiment of the present invention, the concentration of platelet exosomes in the pharmaceutical composition is 2.3 E12 to 2.5 E12 cells / mL or 0.5 to 50 μg / mL.

[0018] In a particular embodiment of the present invention, the skin condition is selected from one or more of photoaged skin, inflammatory skin, infected skin and traumatic skin.

[0019] In a particular embodiment of the present invention, the photoaged skin is UVB-induced.

[0020] To solve the above technical problems, the second technical solution provided by the present invention is: a platelet exosome, wherein the platelet exosome satisfies one or more of the following conditions:

[0021] (1) The main peak particle size is 120-125 nm;

[0022] (2) an average particle size of 135-140 nm; and

[0023] (3) The protein concentration of the platelet exosomes is 6-7 mg / mL;

[0024] The platelet exosomes are separated from platelets produced by activation of megakaryocytes differentiated from iPSCs;

[0025] The separation is to collect the supernatant in the platelet preparation process, collect the precipitate after centrifugation, and the precipitate is the platelet exosomes;

[0026] The activated megakaryocytes are treated with thrombopoietin, ROCK inhibitor and plasma.

[0027] In a specific embodiment of the present invention, the centrifugation method is differential ultracentrifugation.

[0028] In a specific embodiment of the present invention, the ROCK inhibitor is Y-27632.

[0029] In a specific embodiment of the invention, said plasma is human plasma.

[0030] To solve the above technical problems, the third technical solution provided by the present invention is: a pharmaceutical composition, which comprises the platelet exosomes as described in the second technical solution, and a pharmaceutically acceptable carrier and / or excipient.

[0031] In a specific embodiment of the present invention, the concentration of platelet exosomes in the pharmaceutical composition is 2.3 E12 to 2.5 E12 cells / mL or 0.5 to 50 μg / mL.

[0032] In order to solve the above technical problems, the fourth technical solution provided by the present invention is: an application of the platelet exosomes as described in the second technical solution or the pharmaceutical composition as described in the third technical solution in the preparation of skin care products or cosmetics.

[0033] In a specific embodiment of the present invention, the skin care product is selected from the group consisting of facial cleanser, toner, natural cream, facial mask, lotion, face cream, eye cream, essence, isolation cream, isolation spray and sunscreen;

[0034] The cosmetics are selected from concealer pencils, foundation creams, BB creams, pressed powders, loose powders, eye shadow palettes, blushes, highlighter powders and lip glosses.

[0035] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0036] The reagents and raw materials used in the present invention are commercially available.

[0037] The positive progress effect of the present invention is:

[0038] The present invention provides a human-derived platelet exosome for anti-skin aging, which uses, but is not limited to, megakaryocytes and genetic engineering methods to obtain a large number of platelet exosomes. The platelet exosomes can promote the proliferation of human fibroblasts, thereby promoting collagen secretion, increasing skin thickness, and reducing wrinkles. At the same time, they can reduce cell senescence caused by UV damage and greatly reduce the proportion of senescent cells. They can also promote fibroblast migration and promote tissue repair. The platelet exosomes described in the present invention can significantly repair skin damage, eliminate fine lines, and resist aging. It fills the gap in platelet exosomes in delaying skin aging and has great application prospects in the medical and beauty industries.

[0039] The present invention utilizes platelet exosomes to develop products targeting skin aging (such as skin care products or cosmetics), which can provide a new biological treatment method that may have fewer side effects and higher biocompatibility compared to traditional drug treatments, and is low-cost and easy to produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Shown is a schematic diagram of the process of determining the role of platelet exosomes in alleviating skin aging according to the present invention.

[0041] Figure 2 The image shows the quality identification results of the prepared platelet exosomes. The scale bar on the left side of the electron micrograph is 1 μm, and the scale bar on the right side is 500 nm.

[0042] Figure 3 Shown are the results of Western blotting of prepared platelet exosomes (lane 1, exosomes; lane 2, positive control). Calnexin protein was not expressed in the exosome sample, while the positive control did. Alix, CD9, and CD81 proteins were also expressed in the exosome sample.

[0043] Figure 4 The figure shows platelet exosomes promoting fibroblast proliferation according to Example 1 of the present invention.

[0044] Figure 5 The results of β-galactosidase staining of skin fibroblasts shown in Example 2 of the present invention indicate that platelet exosomes alleviate skin aging.

[0045] Figure 6 The results of the experiment showing that platelet exosomes promote the expression of genes and proteins related to human skin fibroblasts in Example 3 of the present invention indicate that platelet exosomes promote the expression of COLIA1 and Elastin genes and proteins in a concentration-dependent manner.

[0046] Figure 7 The results of the experiment showing that platelet exosomes promote the expression of aging-related proteins in UV-damaged mouse skin tissue according to Example 4 of the present invention indicate that platelet exosomes can alleviate UV damage and promote the expression of COLIA1 and Elastin proteins.

[0047] Figure 8 The figure shows a comparison of the effects of the platelet exosomes of the present invention and the extracellular vesicles in the prior art in promoting fibroblast proliferation. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0049] It should be understood that the terms used in the examples of the present invention are intended to describe specific embodiments and are not intended to limit the scope of protection of the present invention. In the present specification and claims, unless otherwise expressly indicated, the singular forms "a," "an," and "the" include the plural forms. When numerical ranges are given in the examples, it should be understood that unless otherwise indicated, both endpoints of each numerical range and any value between the two endpoints may be used.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. In addition to the specific methods, devices, and materials used in the examples, any prior art methods, devices, and materials similar or equivalent to those in the examples may be used to implement the present invention, based on the knowledge of the prior art by those skilled in the art and the disclosure of this invention.

[0051] Unless otherwise stated, the experimental methods, detection methods, and preparation methods disclosed in the present invention all adopt conventional techniques in this technical field and related fields.

[0052] Test purpose and materials

[0053] The purpose of the present invention is to reveal the function of platelet exosomes in promoting the proliferation and migration of skin fibroblasts and delaying skin aging (see Figure 1 ).

[0054] Platelet exosome preparation

[0055] In the embodiments, iPSCs can be induced to differentiate into megakaryocytes by means other than genetic engineering, and the megakaryocytes produce a large number of platelets (the detailed steps are the same as those in Patent No.: CN 118256430A). In this process, a large amount of platelet-exosome mixture is obtained, which is then extracted and prepared into platelet exosomes of higher purity. Figure 2 The results of NTA, TEM, and BCA tests are shown in Table 1. The results were consistent with the characteristics of exosomes.

[0056] The specific process is as follows:

[0057] (1) Differentiation of iPSCs into hematopoietic progenitor stem cells

[0058] The iPSCs of the present invention are sampled from hospital skin biopsy, and primary fibroblasts are cultured in the laboratory and reprogrammed and screened to obtain an ideal iPSC cell line.

[0059] iPSCs were dissociated into single cells and plated evenly on culture dishes pre-coated with human recombinant laminin in Essentia18 (Thermo) medium supplemented with 30 ng / ml VEGF-A165, 10 ng / ml bFGF, 5 μM Y-27632, 2 mM Chir-99021, and 20 ng / ml Activin A for 2 days. The medium was then changed to HDM medium (IMDM supplemented with 1× ITS, 1× glutamax, 0.45 mM monothioglycerol, 50 ng / ml ascorbic acid, and 20% KO-SRM. Subsequently, 30 ng / ml VEGF-A165, 10 ng / ml bFGF, 20 ng / ml BMP4, 5 μM Y-27632, and 20 ng / ml Activin A were added and cultured for a further 4 days. The culture medium was then replaced with HDM medium supplemented with 30 ng / ml VEGF-A165, 10 ng / ml bFGF, 50 ng / ml SCF, 50 ng / ml thrombopoietin (TPO), 2 U / ml erythropoietin (EPO), and 5 μM Y-27632. 50 ng / ml IL-3 and 50 ng / ml IL-6 were further added and cultured for another 8 days. The suspended hematopoietic progenitor cells (iHPCs) were harvested, and the supernatant containing the iHPCs was collected and centrifuged at 1000 rpm / min for 5 minutes.

[0060] (2) Differentiation and proliferation of megakaryocytes

[0061] iHPCs were plated in culture dishes pre-coated with 0.1% gelatin and cultured for 15-20 days in HDM medium supplemented with 20 ng / ml VEGF-A165, 5 ng / ml bFGF, 50 ng / ml thrombopoietin (TPO), 20 ng / ml IL-3, 20 ng / ml IL-6, 50 ng / ml IL-21, 5 nM tazemetostat, 200 nM eltrombopag, and 200 nM iBET151. The cells were then harvested from the suspended megakaryocytes (iMKs). The iMKs were transferred to low-attachment vials and the culture medium was changed to HDM supplemented with 50 ng / ml thrombopoietin (TPO), 50 ng / ml SCF, 50 ng / ml IL-21, and 5 μM Y-27632. The cells were then expanded on a horizontal shaker at 120-150 rpm. The passage interval was 3 days.

[0062] (3) Platelet production

[0063] iMKs were suspended in PM medium (IMDM supplemented with 1× ITS, 1× glutamax, 0.45 mM thioglycerol, 50 g / ml ascorbic acid, 10 U heparin, and 5% human plasma) supplemented with 50 ng / ml thrombopoietin (TPO) and 5 μM Y-27632 and cultured statically for 1 day. The PM medium was then replaced with 50 ng / ml TPO, 0.5 ng / ml collagen, 5 nM Fingolimod HCl, and 5 μM Y-27632. The cells were cultured statically for 1 day and then continued on a horizontal shaker at 120-150 rpm for another 1 day. The megakaryocytes were then transferred to a bioreactor and cultured for 5-6 days at 37°C and 5% CO2.

[0064] (4) Collection of exosomes

[0065] The supernatant from the platelet preparation process was collected and subjected to gradient centrifugation. The first centrifugation was performed at 300 × g for 10 min at 4°C to remove large cells. The second centrifugation was performed at 4000 × g for 10 min at 4°C to remove small cells. The third centrifugation was performed at 10,000 × g for 30 min at 4°C to remove large vesicles. The fourth ultracentrifugation was performed at 120,000 × g for 70 min at 4°C to concentrate the precipitate, which was the purified exosomes. Aliquot the precipitate to volume with D-PBS and store at -80°C.

[0066] (5) Identification of exosomes

[0067] A portion of the exosomes was subjected to nanoparticle tracking analysis (NTA) to measure the hydrodynamic size of the exosomes and transmission electron microscopy. BCA (BeyoBCA Rapid Protein Concentration Assay Kit, Beyotime, P0398L) was used to measure the exosome protein content according to the kit protocol. The results showed a peak particle size of 123.5 nm, an EV concentration of 2.4 E12 cells / mL, and an exosome protein content of 6.458 mg / mL (Table 1, Figure 2 ).

[0068] Table 1

[0069]

[0070] The results of Western blotting of exosomes showed that ( Figure 3 ), Alix, CD9, and CD81 proteins were expressed, while the negative Calnexin protein was not expressed. The characterization factors strictly followed the three-positive and one-negative principle, which was completely consistent with the characteristics of pure exosomes.

[0071] Example 1: Platelet exosomes promote the proliferation of skin fibroblasts

[0072] Skin fibroblasts (BNCC, BNCC337722) were routinely cultured in DMEM (Gbico, Cat: 11965-092) + 10% FBS (Sigma, Cat: F8318-500ML). Fibroblasts in the logarithmic growth phase were taken and 5×10 3 Skin fibroblasts were cultured in two wells per group. 0.1 mL of control culture medium (skin fibroblast culture medium) and culture medium containing 0.5, 5, and 50 μg / mL platelet exosomes were added, respectively. After culturing in a 37°C 5% CO2 incubator for 3 days, the cell number was determined by CCK8 assay. Cell proliferation rate = (absorbance value of experimental group - absorbance value of control group) / (absorbance value of control group - absorbance value of blank well) × 100%. It was found that platelet exosomes promoted fibroblast proliferation in a concentration-dependent manner within the range of 0.5-50 μg / mL (see Figure 4 ).

[0073] Example 2: Platelet exosomes delay aging of skin fibroblasts

[0074] Skin fibroblasts (BNCC, BNCC337722) were routinely cultured in DMEM (Gbico, Cat: 11965-092) + 10% FBS (Sigma, Cat: F8318-500ML). Fibroblasts in the logarithmic growth phase were taken and 5×10 5 Skin fibroblasts were divided into two wells in each group and damaged by UVB (30 mJ / cm 2 ), the model control group was added with 1 mL of control culture medium (culture medium for skin fibroblasts), the drug group was added with culture medium for skin fibroblasts containing 0.5, 5, and 50 μg / mL platelet exosomes, and a healthy blank control group was also set up. After culturing in a 37°C CO2 incubator for 3 days, staining with the CellEvent™ Senescence Green Flow Cytometry Assay Kit (invitrogen, C10840) showed that the number of β-glucosidase-stained cells in the model control group was significantly increased compared with the healthy blank control group, accounting for 22.9%. The platelet exosome group showed a concentration-dependent decrease in β-glucosidase staining in the range of 0.5-50 μg / mL compared with the model control group, and the decrease to 10.7% at 50 μg / mL exosomes, indicating that exosomes can alleviate fibroblast senescence caused by UVB (see Figure 5 ).

[0075] Example 3: Platelet exosomes promote the expression of genes and proteins related to human skin fibroblasts

[0076] Skin fibroblasts (BNCC, BNCC337722) were routinely cultured in DMEM (Gbico, Cat: 11965-092) + 10% FBS (Sigma, Cat: F8318-500ML). Fibroblasts in the logarithmic growth phase were taken and 5×10 3 Two wells of skin fibroblasts were plated on the second day after plating. The control group was replaced with 0.1 mL of control culture medium (dermal fibroblast culture medium), while the drug groups were replaced with culture medium containing 0.5, 5, and 50 μg / mL platelet-derived exosomes. The cells were cultured in a 37°C CO2 incubator for 24 h. cDNA was prepared using the FlysisAmp Cells-to-cDNA Kit (Novagen, CL111-01). RT-qPCR reactions were performed using ChamQ Universal SYBR qPCR Master Mix (Novagen, Q711-03). The expression levels of COLIA1 (F primer (SEQ ID NO: 1): CCCGGGCCTCAAGGTATTG, R primer (SEQ ID NO: 2): ACGGTCACCCTTGGCG) and Elastin (F primer (SEQ ID NO: 3): GCTCTCGGTGGAGTAGGC, R primer (SEQ ID NO: 4): GCCAGCAGCACCGTATT) were detected. GAPDH was used as an internal control. The same cell treatment procedure was followed, and cells were collected 48 hours later. Western blot analysis was performed to detect the protein expression levels of COLIA1 (Abcam, ab138492) and Elastin (Santa Cruz, sc-374638). The results showed that platelet exosomes promoted the expression of COLIA1 and Elastin genes and proteins in a concentration-dependent manner within the range of 0.5-50 μg / mL (see Figure 6 ).

[0077] Example 4: Platelet exosomes promote the expression of aging-related proteins in UV-damaged mouse skin tissue

[0078] Before modeling, 15 Balb / c nude mice were caged and housed for one week. Mice were randomly divided into a blank group, a UV damage model group, and a UV damage + exosome 0.5, 5, and 50 μg / mL group, with 3 mice in each group. Except for the blank group, which received no treatment, all other mice were anesthetized with ready-to-use tribromoethanol solution (Nanjing Aibei Biotechnology Co., Ltd., M2920) and exposed to UVB (1.40 J / cm 2) The back skin of mice was damaged, and circles of equal size were drawn in the middle area of ​​the back. Then, the drug solution was applied to the skin according to the groups, 200 μL per mouse, and continued for 1 hour. The same drug administration was performed on the second and third days. On the fourth day, the mice were euthanized, and the skin tissue with circles on the back was taken for Western blot analysis. The expression levels of COLIA1 (Santacruz, sc-293182) and Elastin (Santa cruz, sc-374638) proteins were detected. The results showed that in the mouse UV damage model, 50 μg / mL of platelet exosomes can alleviate UV damage and promote the expression of COLIA1 and Elastin proteins (see Figure 7 ).

[0079] Example 5: Comparison of the effects of existing platelet-derived extracellular vesicles and the exosomes of the present invention in promoting the proliferation of skin fibroblasts

[0080] The inventors prepared platelet-derived extracellular vesicles (hereinafter referred to as extracellular vesicles) with reference to 2.1 Materials and Methods in reference [2].

[0081] Skin fibroblasts (BNCC, BNCC337722) were routinely cultured in DMEM (Gbico, Cat: 11965-092) + 10% FBS (Sigma, Cat: F8318-500ML). Fibroblasts in the logarithmic growth phase were cultured and 5×10 3 Skin fibroblasts were cultured in two wells in each group. 0.1 mL of culture medium as a control, culture medium containing 0.5, 5, or 50 μg / mL platelet exosomes or extracellular vesicles were added, respectively. After culturing in a 37°C 5% CO2 incubator for 3 days, the cell number was determined by CCK8. The cell proliferation rate = (absorbance value of the experimental group - absorbance value of the control group) / (absorbance value of the control group - absorbance value of the blank well) × 100%. It was found that within the range of 0.5-50 μg / mL, the platelet exosomes of the present invention promoted fibroblast proliferation more significantly than existing extracellular vesicles (see Figure 8 ).

[0082] References:

[0083] 1. Sim, X., et al., Understanding platelet generation from megakaryocytes: implications for in vitro-derived platelets[J]. Blood, 2016.127(10): 1227-33.

[0084] 2. Zhu Weidong. Preliminary study on the mechanism by which platelet-derived extracellular vesicles regulate macrophages and purinergic signaling pathways to accelerate wound healing[D]. Southern Medical University, 2022. DOI: 10.27003 / d.cnki.gojyu.2022.000275.

[0085] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention. Any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. The use of platelet exosomes in the preparation of a drug for improving UVB-induced photoaging skin conditions; in, The platelet exosomes are separated from platelets produced by activation of megakaryocytes differentiated from iPSCs; The separation is to collect the supernatant in the platelet preparation process, collect the precipitate after centrifugation, and the precipitate is the platelet exosomes; The activated megakaryocytes were treated with thrombopoietin, ROCK inhibitor Y-27632 and plasma.

2. The use according to claim 1, characterized in that The platelet exosomes meet one or more conditions selected from the following: (1) The main peak particle size is 120-125 nm; (2) an average particle size of 135-140 nm; and (3) The protein concentration of the platelet exosomes is 6-7 mg / mL.

3. The use according to claim 1, characterized in that The centrifugation method is differential ultracentrifugation.

4. The use according to any one of claims 1 to 3, wherein The medicine is a pharmaceutical composition, which further comprises pharmaceutically acceptable excipients.

5. The use according to claim 4, characterized in that The auxiliary material is a carrier.

6. The use according to claim 4, characterized in that The concentration of platelet exosomes in the pharmaceutical composition is 2.3 E12 to 2.5 E12 cells / mL or 0.5 to 50 μg / mL.

7. Use of platelet exosomes in the preparation of skin care products or cosmetics for improving UVB-induced photoaging skin conditions; in, The platelet exosomes are separated from platelets produced by activation of megakaryocytes differentiated from iPSCs; The separation is to collect the supernatant in the platelet preparation process, collect the precipitate after centrifugation, and the precipitate is the platelet exosomes; The activated megakaryocytes were treated with thrombopoietin, ROCK inhibitor Y-27632 and plasma.

8. The use according to claim 7, characterized in that The platelet exosomes meet one or more conditions selected from the following: (1) The main peak particle size is 120-125 nm; (2) an average particle size of 135-140 nm; and (3) The protein concentration of the platelet exosomes is 6-7 mg / mL.

9. The use according to claim 7, characterized in that The centrifugation method is differential ultracentrifugation.

10. The use according to any one of claims 7 to 9, characterized in that The skin care products are selected from facial cleansers, toners, natural creams, facial masks, lotions, face creams, eye creams, essences, isolation creams, isolation sprays and sunscreens; The cosmetics are selected from concealer pencils, foundation creams, BB creams, pressed powders, loose powders, eye shadow palettes, blushes, highlighter powders and lip glosses.

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