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Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_764_Библиотеки_им_академика_М_И_Перельмана

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Fig. 24.7 Positioning and healing phases of split-thickness skin graft on dermal substitute
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Fig. 24.8 Scar contracture after burn injuries
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Fig. 24.10 Follow-up after skin grafting onto dermal substitute
Fig. 24.9 Positioning of dermal substitute
medical devices while cell therapy has been clas­sied as an advanced therapy medicinal product (ATMP). In Europe, these therapies are con­trolled by the European Medicines Agency (EMA), a monitoring institute of the European
Union, which is dedicated to the scientic evalu­ation and supervision of access to the medicines market. The European regulation (EC) no. 1394/2007 provides the general framework on the production and use of ATMP within the
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European Union (EU). According to this regula­tion, an ATMP is a “medicine for human use based on genes, cells or tissue engineering.” With the aim of regenerating, repairing, or replacing human tissue, some products may contain or con­sist of engineered cells or tissues and may also contain viable or non-viable cells or tissues of human or animal origin. This means that most skin substitutes with living cells (both autologous and allogeneic), adipose tissue and matrices con­taining human and/or xenogenic material, must be considered according to these regulations while. One of the main features of these regula­tions is that the production of ATMP for human use must take place under conditions of good manufacturing practice (GMP). Each GMP is also linked to the single histological typology.
ATMPs are evaluated by at least three scien­tic committees of the EMA, the CAT (Committee for Advanced Therapies), the CHMP (Committee for Medicinal Products for Human Use), and the PRAC (Pharmacovigilance Risk Assessment Committee).
As required by the ATMP regulation (EC) n. 1394/2007, the scientic evaluation of MAA applications for ATMP is mainly carried out by the Committee for Advanced Therapies (CAT). The CAT prepares a draft opinion on the quality, safety, and efcacy of each ATMP subject to a Marketing Authorization Application (MAA) which is sent for nal approval to the Committee for Medicinal Products for Human Use (CHMP). The CHMP recommendation is then sent to the European Commission, which adopts a binding decision in all Member States.
These stringent regulatory and manufacturing requirements imply intense collaboration between centers to develop new ATMPs and pro­mote their commercial exploitation (EMA European Medicine Agency 2018) and determine the great difference in terms of products and materials between Europe and USA.
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3. Skin substitutes for acute and chronic wound healing: an updated review Christina Dai, Shawn Shih & Amor Khachemoune.
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23. Metcalfe AD, Ferguson MW. Tissue engineering of replacement skin: the crossroads of biomaterials, wound healing, embryonic development, stem cells and regeneration. J R Soc Interface. 2007;4(14):413–
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26. Lee M, et al. Hyaluronic acid dressing (Healoderm) in the treatment of diabetic foot ulcer: a prospective, randomized, placebo-controlled, single-center study. Wound Repair Regen. 2016;24(3):581–8.
27. Choi YS, Hong SR, Lee YM, Song KW, Park MH, Nam YS. Study on gelatin-containing articial skin: I. Preparation and characteristics of novel gelatin­alginate sponge. Biomaterials. 1999;20(5):409–17.
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28. Takemoto S, Morimoto N, Kimura Y, Taira T, Kitagawa T, Tomihata K, Tabata Y, Suzuki S.Preparation of col­lagen/gelatin sponge scaffold for sustained release of bFGF. Tissue Eng Part A. 2008;14(10):1629–38.
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29. Ito T, Suzuki A, Stossel TP. Regulation of water ow by actin-binding protein-induced actin gelatin. Biophys J. 1992;61(5):1301–5.
30. Marino A, Filippeschi C, Genchi GG, Mattoli V, Mazzolai B, Ciofani G. The Osteoprint: a bioin-
spired two-photon polymerized 3-D structure for the enhancement of bone-like cell differentiation. Acta Biomater. 2014;10(10):4304–13.
31. Maheshwari G, Brown G, Lauffenburger DA, Wells A, Grifth LG. Cell adhesion and motility depend on nanoscale RGD clustering. J Cell Sci. 2000;113(10):1677–86.
32. Ng MH, Chowdhury SR, Morshed M, Tan KK, Tan GH, Phang MY, Aminuddin BS, Fauziah O, Ruszymah BH.Effective cell seeding and three-dimensional cell culture for bone tissue engineering. J Biomat Tissue Eng. 2014;4(7):573–8.
33. Supp DM, Boyce ST. Engineered skin substi­tutes: practices and potentials. Clin Dermatol. 2005;23(4):403–12.
34. Balasubramani M, Kumar TR, Babu M.Skin substi­tutes: a review. Burns. 2001;27(5):534–44. https://doi.
org/10.1016/s0305- 4179(01)00018- 3.
35. Ferreira MC, Paggiaro AO, Isaac C, Teixeira Neto N, Santos GB. Skin substitutes: current concepts and a new classication system. Rev Bras Cir Plást. 2011;26:696–702.
36. American Society for Testing and Materials International (ASTM).
37. Davison-Kotler E, Sharma V, Kang NV, García-Gareta E. A universal classication system of skin substi­tutes inspired by factorial design. Tissue Eng Part B Rev. 2018;24(4):279–88. https://doi.org/10.1089/
ten.TEB.2017.0477. Epub 2018 Feb 12. PMID:
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38. Schiavon M, et al. The use of Integra dermal regeneration template versus aps for reconstruc­tion of full-thickness scalp defects involving the Calvaria: a cost-benet analysis. Aesthet Plast Surg. 2016;40(6):901–7.
39. Montanaro M, et al. Macrophage activation and M2 polarization in wound bed of diabetic patients treated by dermal/epidermal substitute Nevelia. Int J Low Extrem Wounds. 2020;21:1534734620945559.
40. Chafn AE, Dowling SG, Kosyk MS, Bosque BA.Surgical reconstruction of pilonidal sinus disease with concomitant extracellular matrix graft placement: a case series. J Wound Care. 2021;30(Sup7):S28–34.
41. Alam K, Jeffery SLA. Acellular sh skin grafts for management of split thickness donor sites and partial thickness burns: a case series. Mil Med. 2019;184(Suppl 1):16–20.
42. Michael S, Winters C, Khan M.Acellular sh skin graft use for diabetic lower extremity wound healing: a retrospective study of 58 ulcerations and a literature review. Wounds. 2019;31(10):262–26.
43. Lun S, Irvine SM, Johnson KD, Fisher NJ, Floden EW, Negron L, Dempsey SG, McLaughlin RJ, Vasudevamurthy M, Ward BR, May BC.A functional extracellular matrix biomaterial derived from ovine forestomach. Biomaterials. 2010;31(16):4517–29.
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hed.23458.
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Mesenchymal Cells fromAdipose
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Tissue
PaoloPersichetti, GiovanniFrancescoMarangi, CarloMirra, MarcoGratteri, andLucreziaArcari
25
25.1 Introduction
Mesenchymal stem cells are tissue-specic stem cells that meet the minimum criteria proposed by the International Society for Cellular Therapy (ISCT) in 2006:
1. plastic adhesion under standard culture conditions;
2. expression of the surface markers CD73, CD90, CD105, and the lack of expression of the markers CD14, CD34, CD45, CD11b, CD79a, CD19, and HLA-DR;
3. ability to differentiate into osteoblasts, chon­drocytes, and adipocytes invitro [1].
Although these characteristics are common to all mesenchymal stem cells, there are slight dif­ferences depending on the tissue of origin. In fact, these cells, rst isolated in bone marrow, have been found to reside in many other tissues of the body, such as adipose tissue, synovial uid, dental pulp, endometrium, peripheral blood, sali­vary glands, skin, placenta and fetal membrane,
P. Persichetti (*) · G. F. Marangi · C. Mirra M. Gratteri · L. Arcari Plastic Surgery Unit, Campus Bio Medico University, Rome, Italy e-mail: p.persichetti@unicampus.it;
g.marangi@policlinicocampus.it; c.mirra@unicampus.it; m.gratteri@unicampus.it; lucrezia.arcari@unicampus.it
Wharton’s jelly of the umbilical cord, and amni­otic uid and membrane [2].
Although these cells can be obtained from various sources, adipose tissue-derived stem cells (ADSCs) are mainly used in regenerative medi­cine. These cells meet several requirements that make them ideal for tissue engineering:
– they are present in abundant quantities (more
than 1 billion cells per individual);
– they can be harvested using minimally inva-
sive procedures;
– they are able to differentiate into multiple cell
lines in a controlled and reproducible manner;
and controlled and reproducible manner;
– can be transplanted autologously; – can be expanded in accordance with CGMP
guidelines (current Good Manufacturing
Practice) guidelines [3].
Adipose-derived stem cells are autologous mes­enchymal stem cells rst identied by Zuk etal. in 2001 from processed lipoaspirates [4]. These authors identied broblast-like cells capable of self-renewal and dened the multipotency of these cells by their ability to differentiate in a chondro­genic, osteogenic, adipogenic, and myogenic direc­tion. Recent studies have demonstrated the pluripotency of these cells, as they can also differen­tiate into non-mesodermal cell lines [5]. The local­ization of ADSCs within the adipose tissue is not yet clearly known. Traktuev etal. showed that these
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. Maruccia et al. (eds.), Pearls and Pitfalls in Skin Ulcer Management,
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cells have a predominantly perivascular localization (at the interface between the endothelium and adi­pocytes) and that they are rarely scattered between adipocytes [6]. Maumus etal. identied their pres­ence in the stroma of adipose tissue [7] while Lin etal. identied ADSCs in the capillaries and adven­titia tunica of the largest vessels [8].
25.2 Immunophenotype
The immunophenotype consists of the immuno­typing of surface and intracellular molecules, called differentiation clusters (CDs), to dene cell populations at different stages of their develop­ment by means of ow cytometry and immuno­histochemistry studies. ADSCs express typical mesenchymal markers, i.e., CD13, CD29, CD44, CD63, CD73, CD90, and CD105 whereas they are negative for hematopoietic markers, such as CD14, CD31, CD45, and CD144. As there are no single markers to uniquely identify the cellular subpopulations of SVF, the International Fat Applied Technology Society (IFATS) in 2013 identied the minimum phenotypic criteria that characterize uncultured stromal vascular fraction and cultured ADSCs. In SVF, native ADSCs are characterized by the lack of expression of CD45, CD235a, CD31, while they are positive for CD34, accounting for 20% of the entire SVF.Specically, CD235a is used to assess contamination of ery­throid lineage cells; CD45 is a marker conven­tionally used to identify cells of hematopoietic origin (except red blood cells); and CD31 identi­es endothelial cells and their precursors.
ADSCs in culture are dened as positive for CD73, CD90, CD105, CD44 and negative for CD45 and CD31 [9].
More controversial is the expression of CD34; its expression is positive in the rst passages of culture and then becomes negative in subsequent subcultures. The loss of CD34 expression accord­ing to Suga etal. would appear to be due to the physiological process of commitment or differ­entiation of ADSCs. Indeed, these authors dem­onstrated that the CD34+ subpopulation at the rst culture passages shows a higher proliferative rate than the CD34- subpopulation, which is characterized by for an increased differentiative
capacity in an adipogenic and osteogenic direc­tion [10]. Other authors believe, however, that the loss of CD34 expression is due to the lack of the microenvironment present in culture invivo [11].
ADSCs thus represent a heterogeneous popu­lation of cells, which present a dynamic pheno­type that changes during culture passages [12]. In this regard, Li etal. conducted a study in 2011 to dene the cell subpopulations in the stromal vas­cular fraction and assess their differentiation potential in an adipogenic sense. Four subpopula­tions were identied:
1. CD146+/CD31-/CD34- pericytes
2. mature endothelial cells CD31+/CD34-
3. premature CD31+/CD34+ endothelial cells
4. CD31-/CD34+/CD146-/CD90+
preadipocytes
The subpopulation present in the greatest quantity were the preadipocytes (67.6%), which showed the greatest proliferative rate and differ­entiation in the adipogenic direction [13].
25.3 Secretion ofGrowth Factors
The ability to differentiate toward specic cell lines represents one of the different mechanisms by which ADSCs initiate tissue repair and regenera­tion. These cells have been found to possess para­crine activity, being able to secrete various growth factors such as bFGF (basic broblast growth fac­tor), VEGF (vascular endothelial growth factor), IGF-1 (insulin-like growth factor 1), HGF (hepato­cyte growth factor), and TGF-b1 (transforming growth factor beta 1). This characteristic also makes these cells particularly promising for the treatment of ischemia. Indeed, hypoxia provides a stimulus for the secretion of these growth factors, which promote angiogenesis and tissue repair.
ADSCs are also responsive to the growth factors bFGF and PDGF (platelet-derived growth factor), released from damaged extracellular matrix and activated platelets respectively, which stimulate cell proliferation, leading to more efcient regen­eration. ADSCs also express receptors for the growth factors VEGF, HGF, and EGF (epidermal growth factor). VEGF stimulates cell migration
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and promotes chondrogenic differentiation, HGF promotes hepatogenic differentiation invitro, and EGF inhibits adipogenic differentiation [14].
Also included in the secretome of ADSCs are the cytokines IL-6, IL-7, IL-8, IL-11 TNF-a, the factors G-CSF and M-CSF (granulocyte and macrophage colony-stimulating factors), and adi­pokines, released in response to inammatory stimuli [15].
25.4 Immunomodulatory
Properties
Similar to bone marrow-derived mesenchymal stem cells, ADSCs have been shown to possess immunomodulatory properties, including the ability to restore immune tolerance. Indeed, these cells have shown the following characteristics.
– the lack of expression of human leukocyte
antigens (HLA) class II;
– the ability to inhibit pro-inammatory
cytokines;
– the ability to stimulate the production of the
anti-inammatory cytokine IL-10;
– the induction of the antigen-specic response
of regulatory T lymphocytes.
These characteristics have enabled these cells to be used in the treatment of immunological dis­eases and have made them safe for use in both autologous and allogeneic transplantation [16,
17].
25.5 Dierentiation ofADSCs
ADSCs are capable of differentiating into multi­ple cell lines both invivo and invitro. The rst studies conducted by Zuk et al. on ADSCs had shown the ability of these cells to differentiate into mesodermal cell lines; later studies, how­ever, demonstrated the ability to differentiate into cells of endodermal and ectodermal origin through a process of cross-differentiation, which is why they are now considered pluripotent cells [18, 19] Fig.25.1.
Fig. 25.1 The differentiation capability of ADSCs
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25.6 Mesodermal Lines
25.6.1 Adipogenic Dierentiation
ADSCs show a greater capacity for adipogenic differentiation than bone marrow-derived mes­enchymal stem cells, which show a greater capacity for osteogenic differentiation [20]. The culture medium used for adipogenic differ­entiation typically contains the following induction factors: insulin, IBMX (3-isobutyl­1-methylxanthine, a phosphodiesterase inhibi­tor that increases levels of the second messenger cAMP), dexamethasone, rosiglitazone, and indomethacin. At 7days after exposure to the induction factors, the stem cell begins to acquire the phenotype of a mature adipocyte through the formation of multiple intracytoplasmic lipid droplets, detectable by Oil Red O or Nile Red staining. These fat accumulations gradually increase in size to merge into a single lipid droplet over 2–3 weeks, giving rise to the mature unilocular adipocyte. During this period, the extracellular matrix proteins bro­nectin, laminin, and various types of collagen are expressed. The differentiation process occurs through the expression of genes specic to the mature adipocyte, such as PPAR-g2 (per­oxisome proliferator-activated receptor), leptin, aP2 (adipocyte protein 2), LPL (lipoproteinli­pase), and glucose transporter type 4 [21]. In vivo differentiation can be achieved through the use of scaffolds containing specic biomole­cules that stimulate the differentiation of ADSCs in situ. The scaffolds used include type I collagen, brin, alginate, hyaluronic acid, and matrigel. ADSCs can also be associated with matrices, making the differentiation process even more efcient. From a clinical point of view, ADSCs, combined with different bioma­terials and implanted in the subcutis, can be used to promote regeneration of the adipose tis­sue in the treatment of volume defects, breast reconstruction, lipodystrophy, and congenital malformations [22].
25.6.2 Chondrogenic Dierentiation
The chondrogenic differentiation capacity of ADSCs has made it possible to use these cells as a therapeutic alternative to autologous chondro­cyte cultures in the repair of articular cartilage damage. In vitro chondrogenic differentiation can be achieved by supplementing the culture medium with BMP-6, TGF- b, dexamethasone, ascorbate-2-phosphate, and IGF-1. For this type of differentiation, the cells require a three­dimensional microenvironment, which is achieved with a culture technique called “micro­mass pellet culture.” This technique mimics the condensation of pre-cartilage that occurs during embryonic development and promotes cell-cell interaction and the production of cartilage-like matrix. After 1–2weeks, differentiated chondro­cytes express type II and type IV collagen, aggre­can, prolyl endopeptidase, and proteoglycan sulfate, all components of the cartilage-like extracellular matrix. These cells can be high­lighted with Alcian Blue staining and staining for type II collagen [23, 24]. The scaffolds used to induce the differentiation of ADSCs into chon­drocytes invivo are alginate, agarose, brin, gel­atin, and chondroitin sulfate [25]. This differentiation capacity makes ADSCs a promis­ing cell therapy for reconstructive surgery of the nose and ear and for regeneration of interverte­bral disks, tendons, and articular cartilage dam­aged by acute trauma or chronic diseases such as osteoarthritis [26, 27].
25.6.3 Osteogenic Dierentiation
Osteogenic differentiation of ADSCs in vitro is achieved over 2–4 weeks using media enriched with 1,25 dihydroxyvitamin D3, ascorbate- 2­phosphate, BMP-2, and b-glycerophosphate. Osteoblasts are characterized by the production of calcium phosphate in the extracellular matrix, which can be detected with Alizarin Red or von Kossa staining. During osteogenesis, the follow-
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ing genes are expressed: alkaline phosphatase, type I collagen, osteopontin, osteocalcin, bone sialoprotein, Runx-1, BMP-2, BMP-4, the para­thormone receptor, and BMP 1 and 2 receptors [28].
In vivo differentiation into osteocytes is achieved using bioceramics, such as hydroxyapa­tite and b-tricalcium phosphate, which mimic bone architecture. Other biomaterials used are collagen (being one of the fundamental compo­nents of bone tissue), or synthetic polymers, such as PCL or PLA [29]. The osteogenic differentia­tion of ADSCs has given rise to a line of research for their use in the regeneration of bone tissue following trauma or congenital defects. The abil­ity to repair defects of the cranial bones, mandi­ble and maxilla, has been demonstrated [30, 31].
25.6.4 Myogenic Dierentiation
In vitro, ADSCs are able to differentiate into both smooth and skeletal muscle cells. Differentiation into skeletal muscle cells is achieved in medium enriched with horse serum, hydrocortisone, and dexamethasone through the expression of the muscle-specic transcription factors MyoD and myogenin. ADSCs fuse to form multinucleated myotubes and express skeletal muscle lineage surface proteins such as myosin heavy chain [32]. Differentiation into smooth muscle cells is docu­mented by the expression of smooth muscle a-actin, calponin, and SM22-a [33]. The capacity for myogenic differentiation has also been dem­onstrated invivo. In mdx mouse models (which have a mutation in the DMD gene coding for a non-functioning dystrophin) treatment with ADSCs showed the restoration of dystrophin­expressing muscle bers. These results support the possible use of ADSCs as a cell therapy for degenerative muscle diseases such as Duchenne muscular dystrophy [34]. Differentiation into smooth muscle cells invivo has also been dem­onstrated in mouse models by injecting ADSCs into the urethra and bladder, and morphologically and phenotypically documenting the incorpora­tion and differentiation of these cells into smooth muscle [35] In 2003, Rangappa etal. showed the
ability of ADSCs to differentiate into cardiomyo­cytes in culture medium containing 5- azacytidine. After 3weeks of culture, the adipose stem cells acquire a cardiomyocyte-like morphology and spontaneous contractile activity. These cells are immunostained positive for myosin heavy chain, troponin I, and a-actinin [36]. ADSCs are also capable of spontaneously differentiating into myocardiocytes. After 11–14 days of culture, some cells begin to show contractile activity rem­iniscent of cardiomyocytes and myotube-like structures appear. At 20–30 days of culture, branched cardiac muscle bers are observed. During cardiomyogenesis, cardiomyocyte­specic transcription factors GATA-4 and Nkx2.5, ventricular and atrial myosin light chains (MLC-2v and MLC2-a), and atrial natriuretic peptide are expressed [37]. ADSCs may, there­fore, promote myocardial regeneration, also con­sidering the positive contribution of paracrine activity, which stimulates neoangiogenesis and immunomodulatory properties. In vivo, however, only a small percentage of stem cells are able to undergo cardiomyogenic differentiation. In this regard, it has been shown that exposure to bro­nectin, which occurs 12 hours after myocardial infarction, stimulates the engraftment and prolif­eration of ADSCs in the infarcted tissue [38].
25.7 Non-mesodermal Lines
25.7.1 Neuronal Dierentiation
Neurogenesis showed the ability of ADSCs to give rise to cells derived from ectodermal tissue. The culture medium used to achieve neuronal dif­ferentiation is enriched with butyl hydroxyani­sole, valproic acid, insulin, EGF, and FGF.The stem cells acquire neuronal morphology through the expression of the following markers: neuron­specic enolase, nestin, b-tubulin III, the MAP2, and NeuN intermediate laments. It has also been shown that ADSCs can also differentiate into glial lineage cells by expressing the corre­sponding markers, i.e., S100, p75 NGFR (nerve growth factor receptor), NG2 (nerve glial antigen
2), and the glial brillary acidic protein. They are