Plasma-Based Scaffold Containing Bone-Marrow Mononuclear Cells Promotes Wound Healing in a Mouse Model of Pressure Injury.

Pressure injuries, or pressure ulcers, are a common problem that may lead to infections and major complications, besides being a social and economic burden due to the costs of treatment and hospitalization. While surgery is sometimes necessary, this also has complications such as recurrence or wound dehiscence. Among the newer methods of pressure injury treatment, advanced therapies are an interesting option. This study examines the healing properties of bone marrow mononuclear cells (BM-MNCs) embedded in a plasma-based scaffold in a mouse model. Pressure ulcers were created on the backs of mice (2 per mouse) using magnets and assigned to a group of ulcers that were left untreated (Control, n = 15), treated with plasma scaffold (Plasma, n = 15), or treated with plasma scaffold containing BM-MNC (Plasma + BM-MNC, n = 15). Each group was examined at three time points (3, 7, and 14 days) after the onset of treatment. At each time point, animals were subjected to biometric assessment, bioluminescence imaging, and tomography. Once treatment had finished, skin biopsies were processed for histological and wound healing reverse transcription polymerase chain reaction (RT-PCR) array studies. While wound closure percentages were higher in the Plasma and Plasma + BM-MNC groups, differences were not significant, and thus descriptive data are provided. In all individuals, the presence of donor cells was revealed by immunohistochemistry on posttreatment onset Days 3, 7, and 14. In the Plasma + BM-MNC group, less inflammation was observed by positron emission tomography-computed tomography (PET/CT) imaging of the mice at 7 days, and a complete morphometabolic response was produced at 14 days, in accordance with histological results. A much more pronounced inflammatory process was observed in controls than in the other two groups, and this persisted until Day 14 after treatment onset. RT-PCR array gene expression patterns were also found to vary significantly, with the greatest difference noted between both treatments at 14 days when 11 genes were differentially expressed.

Role of Klotho and AGE/RAGE-Wnt/ß-Catenin Signalling Pathway on the Development of Cardiac and Renal Fibrosis in Diabetes.

Fibrosis plays an important role in the pathogenesis of long-term diabetic complications and contributes to the development of cardiac and renal dysfunction. The aim of this experimental study, performed in a long-term rat model, which resembles type 1 diabetes mellitus, was to investigate the role of soluble Klotho (sKlotho), advanced glycation end products (AGEs)/receptor for AGEs (RAGE), fibrotic Wnt/ß-catenin pathway, and pro-fibrotic pathways in kidney and heart. Diabetes was induced by streptozotocin. Glycaemia was maintained by insulin administration for 24 weeks. Serum and urine sKlotho, AGEs, soluble RAGE (sRAGE) and biochemical markers were studied. The levels of Klotho, RAGEs, ADAM10, markers of fibrosis (collagen deposition, fibronectin, TGF-ß1, and Wnt/ß-catenin pathway), hypertrophy of the kidney and/or heart were analysed. At the end of study, diabetic rats showed higher levels of urinary sKlotho, AGEs and sRAGE and lower serum sKlotho compared with controls without differences in the renal Klotho expression. A significant positive correlation was found between urinary sKlotho and AGEs and urinary albumin/creatinine ratio (uACR). Fibrosis and RAGE levels were significantly higher in the heart without differences in the kidney of diabetic rats compared to controls. The results also suggest the increase in sKlotho and sRAGE excretion may be due to polyuria in the diabetic rats.

Stem cell and tissue engineering approaches in pressure ulcer treatment.

CONTEXT: Pressure ulcers or injuries, arise from ischemic damage to soft tissues induced by unrelieved pressure over a bony prominence. They are usually difficult to treat with standard medical therapy and often they recur. In the search for better treatment options, promising alternative forms of treatment are today emerging. Within the field of regenerative medicine, ongoing research on advanced therapies seeks to develop medicinal products based on gene therapy, somatic cell therapy, tissue-engineering and combinations of these. OBJECTIVE: The main objective is to perform an overview of experimental and clinical developments in somatic cell therapy and tissue engineering targeting the treatment of pressure injuries. METHODS: Searching terms as "PRESSURE ULCER", "STEM CELL THERAPY", "TISSUE ENGINEERING" or "WOUND HEALING" were used in combination or alone, including publications refered to basic and clinical research and focusing on articles showing results obtained in a clinical context. A total of 80 references are cited, including 23 references published in the 3 last years. RESULTS: The results suggest that this form of treatment could be an interesting option in patients with difficult-to-treat ulcers as spinal cord injury patients. CONCLUSION: This field of regenerative medicine is very broad and further research is warranted.

Stem Cell Educator therapy in type 1 diabetes: From the bench to clinical trials.

Type 1 diabetes (T1D) is an autoimmune disease that causes a deficit of pancreatic islet ß cells. Millions of individuals worldwide have T1D, and its incidence increases annually. Recent clinical trials have highlighted the limits of conventional immunotherapy in T1D and underscore the need for novel treatments that not only overcome multiple immune dysfunctions, but also help restore islet ß-cell function. To address these two key issues, we have developed a unique and novel procedure designated the Stem Cell Educator therapy, based on the immune education by cord-blood-derived multipotent stem cells (CB-SC). Over the last 10 years, this technology has been evaluated through international multi-center clinical studies, which have demonstrated its clinical safety and efficacy in T1D and other autoimmune diseases. Mechanistic studies revealed that Educator therapy could fundamentally correct the autoimmunity and induce immune tolerance through multiple molecular and cellular mechanisms such as the expression of a master transcription factor autoimmune regulator (AIRE) in CB-SC for T-cell modulation, an expression of Galectin-9 on CB-SC to suppress activated B cells, and secretion of CB-SC-derived exosomes to polarize human blood monocytes/macrophages into type 2 macrophages. Educator therapy is the leading immunotherapy to date to safely and efficiently correct autoimmunity and restore ß cell function in T1D patients.

Treatment of pressure ulcers in patients with spinal cord injury: Conventional surgery vs. cellular therapy.

CONTEXT: Relapse and recurrence rates of pressure injuries (PIs) are very high in spinal cord injured patients. That is the reason why alternative therapies, such the stem cells derived from bone marrow, have been developed. OBJECTIVE: To compare this new technique of infiltration-infusion of mononuclear cells from bone marrow with conventional surgery. DESIGN: A retrospective study was carried out in patients with spinal cord injuries who had PIs, category III/IV, in the pelvic area, during a 14-year follow-up period. SETTING: One group was treated with conventional surgery and, in the other group, mononuclear cells were infused. PARTICIPANTS: One hundred and forty-nine patients were registered, 63 (42.3%) in the conventional surgery group and 86 (57.7%) in the mononuclear cell group. RESULTS: A comparative study between these 2 groups was carried out. There were no significant differences in ulcer healing in the first 6 months, but 6 months and one-year post-treatment, they were found. At 6 months, no patient in the conventional surgery group showed dehiscence or fistulization of the wound and, one year after surgery, only 3.17% recurred in the conventional group. In addition, there was a statistically significant relationship between days of hospitalization and the type of bacterial contamination and the intervention group. CONCLUSION: Bone marrow mononuclear cell infusion-infiltration is an alternative treatment for PIs and fistula during the first 6 months, instead of conventional surgery. However, in the medium-long term, conventional surgery is more effective.

Antitumor Potential of Fibulin-5 in Breast Cancer Cells Depends on Its RGD Cell Adhesion Motif.

BACKGROUND/AIMS: Different components of the tumor microenvironment can be either tumor-promoting or tumor-suppressive agents depending on factors which are not fully understood. Fibulins are components of the extracellular matrix from different tissues and constitute a clear example of this dual function. In fact, fibulins may either support tumor growth or abolish progression of malignant cells depending on the crosstalk between tumor cells and their surrounding stroma through mechanisms that remain to be elucidated. Among all fibulins, fibulin-5 contains a particular structural hallmark which consists in the presence of a RGD motif within its architecture. Previous reports have highlighted the importance of the interaction of this motif with integrins, and not only in normal functions but also in a tumor context. METHODS: Site-Directed Mutagenesis technique was employed to introduce the change RGD to RGE (RGD-to-RGE) within Fbln5 cDNA sequence. Cell proliferation was measured using the MTT assay or by counting Ki-67 positive cell nuclei. Cell adhesion was analysed using culture plates coated with different extracellular matrix components. Cell invasion was evaluated using 24-well Matrigel-coated invasion chambers, and mammosphere formation was monitored using ultralow attachment culture plates. BALB/c mice were employed to induce subcutaneous tumors. RESULTS: The RGD-to-RGE change alters the capacity of breast cancer cells to adhere to different extracellular matrix proteins as well as to αvß3 and α5ß1 integrins, and promotes protumor effects using different cell-based assays. Moreover, 4T1 cells, a mouse breast cancer cell line model, shows an increased capacity to generate tumors when exogenously expresses fibulin-5 with a RGD-to-RGE change, and such capacity is similar to that shown for 4T1 cells with an interfered Fbln5 gene. CONCLUSION: These data highlight the importance of the RGD motif of fibulin-5 to induce antitumor effects and provide new insights into the involvement of fibulins in tumor processes.

Tissue-engineering approaches in pancreatic islet transplantation.

Pancreatic islet transplantation is a promising alternative to whole-pancreas transplantation as a treatment of type 1 diabetes mellitus. This technique has been extensively developed during the past few years, with the main purpose of minimizing the complications arising from the standard protocols used in organ transplantation. By using a variety of strategies used in tissue engineering and regenerative medicine, pancreatic islets have been successfully introduced in host patients with different outcomes in terms of islet survival and functionality, as well as the desired normoglycemic control. Here, we describe and discuss those strategies to transplant islets together with different scaffolds, in combination with various cell types and diffusible factors, and always with the aim of reducing host immune response and achieving islet survival, regardless of the site of transplantation.

The role of bone marrow mononuclear cell-conditioned medium in the proliferation and migration of human dermal fibroblasts.

BACKGROUND: Several recent studies have demonstrated the great potential of bone marrow cells in regenerative medicine, not only for their ability to differentiate to match a damaged cell type, but also because they synthesize and release various growth factors and cytokines.We examined the effect of bone marrow cell-conditioned medium in the healing process, especially in terms of fibroblast proliferation and migration. METHODS: These in vitro studies consisted of co-culture (without direct contact) of dermal fibroblasts with mononuclear bone marrow cells and the use of conditioned medium obtained from these cultures in a scratch wound model. RESULTS: Mononuclear cells were found to increase the proliferation of fibroblasts, and the conditioned medium showed a stimulatory effect on the migration of fibroblasts. CONCLUSION: When considered together with the observed increase in growth factor levels in conditioned medium, it appears that these cells act through a paracrine mechanism.

Fibroblasts accelerate islet revascularization and improve long-term graft survival in a mouse model of subcutaneous islet transplantation.

Pancreatic islet transplantation has been considered for many years a promising therapy for beta-cell replacement in patients with type-1 diabetes despite that long-term clinical results are not as satisfactory. This fact points to the necessity of designing strategies to improve and accelerate islets engraftment, paying special attention to events assuring their revascularization. Fibroblasts constitute a cell population that collaborates on tissue homeostasis, keeping the equilibrium between production and degradation of structural components as well as maintaining the required amount of survival factors. Our group has developed a model for subcutaneous islet transplantation using a plasma-based scaffold containing fibroblasts as accessory cells that allowed achieving glycemic control in diabetic mice. Transplanted tissue engraftment is critical during the first days after transplantation, thus we have gone in depth into the graft-supporting role of fibroblasts during the first ten days after islet transplantation. All mice transplanted with islets embedded in the plasma-based scaffold reversed hyperglycemia, although long-term glycemic control was maintained only in the group transplanted with the fibroblasts-containing scaffold. By gene expression analysis and histology examination during the first days we could conclude that these differences might be explained by overexpression of genes involved in vessel development as well as in ß-cell regeneration that were detected when fibroblasts were present in the graft. Furthermore, fibroblasts presence correlated with a faster graft re-vascularization, a higher insulin-positive area and a lower cell death. Therefore, this work underlines the importance of fibroblasts as accessory cells in islet transplantation, and suggests its possible use in other graft-supporting strategies.

Platelet-Derived Mitochondria Display Embryonic Stem Cell Markers and Improve Pancreatic Islet ß-cell Function in Humans.

Diabetes is a major global health issue and the number of individuals with type 1 diabetes (T1D) and type 2 diabetes (T2D) increases annually across multiple populations. Research to develop a cure must overcome multiple immune dysfunctions and the shortage of pancreatic islet ß cells, but these challenges have proven intractable despite intensive research effort more than the past decades. Stem Cell Educator (SCE) therapy-which uses only autologous blood immune cells that are externally exposed to cord blood stem cells adhering to the SCE device, has previously been proven safe and effective in Chinese and Spanish subjects for the improvement of T1D, T2D, and other autoimmune diseases. Here, 4-year follow-up studies demonstrated the long-term safety and clinical efficacy of SCE therapy for the treatment of T1D and T2D. Mechanistic studies found that the nature of platelets was modulated in diabetic subjects after receiving SCE therapy. Platelets and their released mitochondria display immune tolerance-associated markers that can modulate the proliferation and function of immune cells. Notably, platelets also expressed embryonic stem cell- and pancreatic islet ß-cell-associated markers that are encoded by mitochondrial DNA. Using freshly-isolated human pancreatic islets, ex vivo studies established that platelet-releasing mitochondria can migrate to pancreatic islets and be taken up by islet ß cells, leading to the proliferation and enhancement of islet ß-cell functions. These findings reveal new mechanisms underlying SCE therapy and open up new avenues to improve the treatment of diabetes in clinics. Stem Cells Translational Medicine 2017;6:1684-1697.

Organ Donation and Elective Ventilation: A Necessary Strategy.

Organ transplantation is the sole treatment to improve or save the life of patients with final-stage organ failure. The shortage of available organs for transplantation constitutes a universal problem, estimating that 10% of patients on waiting lists die. Brain death is an undesirable result; nevertheless, it has beneficial side-effects since it is the most frequent source of organs for transplantation. However, this phenomenon is relatively uncommon and has a limited potential. One of the options that focuses on increasing organ donation is to admit patients with catastrophic brain injuries (with a high probability of brain death and nontreatable) to the Intensive Care Unit, with the only purpose of donation. To perform elective nontherapeutic ventilation (ENTV), a patient's anticipated willingness to donate organs and/or explicit acceptance by his/her relatives is required. This process should focus exclusively on those patients with catastrophic brain injuries and imminent risk of death which, due to its acute damage, are not considered treatable. This article defends ENTV as an effective strategy to improve donation rate, analyzing its ethical and legal basis.

Cleavage of Fibulin-2 by the aggrecanases ADAMTS-4 and ADAMTS-5 contributes to the tumorigenic potential of breast cancer cells.

Fibulin-2 participates in the assembly of extracellular matrix components through interactions with multiple ligands and promotes contacts between cells and their surrounding environment. Consequently, identification of processes that could lead to an altered Fibulin-2 could have a major impact not only in the maintenance of tissue architecture and morphogenesis but also in pathological situations including cancer. Herein, we have investigated the ability of the secreted metalloproteases ADAMTS-4 and ADAMTS-5 to digest Fibulin-2. Using in vitro approaches and cultured breast cancer cell lines we demonstrate that Fibulin-2 is a better substrate for ADAMTS-5 than it is for ADAMTS-4. Moreover, Fibulin-2 degradation is associated to an enhancement of the invasive potential of T47D, MCF-7 and SK-BR-3 cells. We have also found that conditioned medium from MCF-7 cells that simultaneously overexpress Fibulin-2 and ADAMTS-5 significantly induced the migratory and invasive ability of normal breast fibroblasts using 3D collagen matrices. Immunohistochemical analysis highlights the close proximity or partial overlap of both Fibulin-2 and ADAMTS-5 in breast tumor samples. Additionally, proteolytic products derived from a potential degradation of Fibulin-2 by ADAMTS-5 were also identified in these samples. Finally, we also show that the cleavage of Fibulin-2 by ADAMTS-5 is counteracted by ADAMTS-12, a metalloprotease that interacts with Fibulin-2. Overall, our results provide direct evidence indicating that Fibulin-2 is a novel substrate of ADAMTS-5 and that this proteolysis could alter the cellular microenvironment affecting the balance between protumor and antitumor effects associated to both Fibulin-2 and the ADAMTSs metalloproteases.

Effects of Estrogen and Phytoestrogen Treatment on an In Vitro Model of Recurrent Stroke on HT22 Neuronal Cell Line.

An increase of stroke incidence occurs in women with the decline of estrogen levels following menopause. This ischemic damage may recur, especially soon after the first insult has occurred. We evaluated the effects of estrogen and phytoestrogen treatment on an in vitro recurrent stroke model using the HT22 neuronal cell line. HT22 cells were treated with 17ß-estradiol or genistein 1 h after the beginning of the first of two oxygen and glucose deprivation/reoxygenation (OGD/R) cycles. During the second OGD, there was a deterioration of some components of the electron transport chain, such as cytochrome c oxidase subunit 1 with a subsequent increase of reactive oxygen species (ROS) production. Accordingly, there was also an increase of apoptotic phenomena demonstrated by poly(ADP-ribose) polymerase 1 cleavage, Caspase-3 activity, and Annexin V levels. The recurrent ischemic injury also raised the hypoxia-inducible factor 1α and glucose transporter 1 levels, as well as the ratio between the lipidated and cytosolic forms of microtubule-associated protein 1A/1B-light chain 3 (LC3-II/LC3-I). We found a positive effect of estradiol and genistein treatment by partially preserving the impaired cell viability after the recurrent ischemic injury; however, this positive effect does not seem to be mediated neither by blocking apoptosis processes nor by decreasing ROS production. This work contribute to the better understanding of the molecular mechanisms triggered by recurrent ischemic damage in neuronal cells and, therefore, could help with the development of an effective treatment to minimize the consequences of this pathology.

Repair of segmental mandibular bone defects in sheep using bone marrow stromal cells and autologous serum scaffold: a pilot study.

AIM: The aim of this study was to evaluate effective bone regeneration using an autologous serum scaffold (alone or seeded with autologous bone marrow-mesenchymal stem cells, BM-MSCs), when implanted in a 30 mm length segmental mandibular defect in sheep. MATERIALS AND METHODS: The bone defect was filled either with serum scaffold alone (control group; n = 5) or combined with BM-MSCs (experimental group; n = 10). Bone regeneration was determined at 12 (T12; 2 control sheep and 4 experimental sheep) and 32 weeks (T32; 3 control and 6 experimental sheep), as measured by computed and microcomputed tomography and histological examination. RESULTS: Two sheep of the Experimental group died after surgery. While complete bone union in the control group was only observed at T32, it was observed both at T12 (1/4 sheep) and T32 (3/4 sheep) in the experimental group. When properties/characteristics of new bone where compared, a better bone quality, similar to native bone, was observed in the scaffold combined with BM-MSCs. CONCLUSIONS: Based on these results, we conclude that the serum scaffold can promote efficient repair of large bone defects, but the combination with BM-MSCs accelerates this process, increasing significantly the amount and quality of bone formed.

Modulation of Autoimmune T-Cell Memory by Stem Cell Educator Therapy: Phase 1/2 Clinical Trial.

BACKGROUND: Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease that causes a deficit of pancreatic islet ß cells. The complexities of overcoming autoimmunity in T1D have contributed to the challenges the research community faces when devising successful treatments with conventional immune therapies. Overcoming autoimmune T cell memory represents one of the key hurdles. METHODS: In this open-label, phase 1/phase 2 study, Caucasian T1D patients (N = 15) received two treatments with the Stem Cell Educator (SCE) therapy, an approach that uses human multipotent cord blood-derived multipotent stem cells (CB-SCs). SCE therapy involves a closed-loop system that briefly treats the patient's lymphocytes with CB-SCs in vitro and returns the "educated" lymphocytes (but not the CB-SCs) into the patient's blood circulation. This study is registered with ClinicalTrials.gov, NCT01350219. FINDINGS: Clinical data demonstrated that SCE therapy was well tolerated in all subjects. The percentage of naïve CD4(+) T cells was significantly increased at 26 weeks and maintained through the final follow-up at 56 weeks. The percentage of CD4(+) central memory T cells (TCM) was markedly and constantly increased at 18 weeks. Both CD4(+) effector memory T cells (TEM) and CD8(+) TEM cells were considerably decreased at 18 weeks and 26 weeks respectively. Additional clinical data demonstrated the modulation of C-C chemokine receptor 7 (CCR7) expressions on naïve T, TCM, and TEM cells. Following two treatments with SCE therapy, islet ß-cell function was improved and maintained in individuals with residual ß-cell function, but not in those without residual ß-cell function. INTERPRETATION: Current clinical data demonstrated the safety and efficacy of SCE therapy in immune modulation. SCE therapy provides lasting reversal of autoimmune memory that could improve islet ß-cell function in Caucasian subjects. FUNDING: Obra Social "La Caixa", Instituto de Salud Carlos III, Red de Investigación Renal, European Union FEDER Funds, Principado de Asturias, FICYT, and Hackensack University Medical Center Foundation.

Cooperation by fibroblasts and bone marrow-mesenchymal stem cells to improve pancreatic rat-to-mouse islet xenotransplantation.

Experimental and clinical experiences highlight the need to review some aspects of islet transplantation, especially with regard to site of grafting and control of the immune response. The subcutaneous space could be a good alternative to liver but its sparse vasculature is its main limitation. Induction of graft tolerance by using cells with immunoregulatory properties is a promising approach to avoid graft rejection. Both Fibroblasts and Mesenchymal Stem Cells (MSCs) have shown pro-angiogenic and immunomodulatory properties. Transplantation of islets into the subcutaneous space using plasma as scaffold and supplemented with fibroblasts and/or Bone Marrow-MSCs could be a promising strategy to achieve a functional extra-hepatic islet graft, without using immunosuppressive drugs. Xenogenic rat islets, autologous fibroblasts and/or allogenic BM-MSCs, were mixed with plasma, and coagulation was induced to constitute a Plasma-based Scaffold containing Islets (PSI), which was transplanted subcutaneously both in immunodeficient and immunocompetent diabetic mice. In immunodeficient diabetic mice, PSI itself allowed hyperglycemia reversion temporarily, but the presence of pro-angiogenic cells (fibroblasts or BM-MSCs) within PSI was necessary to improve graft re-vascularization and, thus, consistently maintain normoglycemia. In immunocompetent diabetic mice, only PSI containing BM-MSCs, but not those containing fibroblasts, normalized glycemia lasting up to one week after transplantation. Interestingly, when PSI contained both fibroblasts and BM-MSCs, the normoglycemia period showed an increase of 4-times with a physiological-like response in functional tests. Histology of immunocompetent mice showed an attenuation of the immune response in those grafts with BM-MSCs, which was improved by co-transplantation with fibroblasts, since they increased BM-MSC survival. In summary, fibroblasts and BM-MSCs showed similar pro-angiogenic properties in this model of islet xenotransplantation, whereas only BM-MSCs exerted an immunomodulatory effect, which was improved by the presence of fibroblasts. These results suggest that cooperation of different cell types with islets will be required to achieve a long-term functional graft.

Repair of long-bone pseudoarthrosis with autologous bone marrow mononuclear cells combined with allogenic bone graft.

BACKGROUND AIMS: Long-bone pseudoarthrosis is a major orthopedic concern because of numerous factors such as difficulty of the treatment, high recurrence, high costs and the devastating effects on the patients' quality of life, which sometimes ends in amputation. Although the "gold standard" for the treatment of this pathology is autologous bone grafting, which has high osteogenic, osteoconductive and osteoinductive properties, this treatment presents some restrictions such as the limited amount of bone that can be taken from the patient and donor site morbidity. Bone marrow mononuclear cells (BM-MNCs) comprise progenitor and stem cells with pro-angiogenic and pro-osteogenic properties. Allogenic cancellous bone graft is a natural and biodegradable osteoconductive and osteoinductive scaffold. Combination of these two components could mimic the advantages of autologous bone grafting while avoiding its main limitations. METHODS: Long-bone pseudoarthrosis was treated in seven patients with autologous BM-MNCs from iliac crest combined with frozen allogenic cancellous bone graft obtained from the tissue bank. RESULTS: All patients showed complete bone consolidation 5.3 ± 0.9 months (range, 2-9 months) after cell transplantation. Moreover, limb pain disappeared in all of them. The mean follow-up was 35.8 ± 4.6 months after transplantation (range, 24-51 months) without pseudoarthrosis recurrence or pain reappearing. CONCLUSIONS: Combination of autologous BM-MNCs and allogenic bone graft could constitute an easy, safe, inexpensive and efficacious attempt to treat long-bone pseudoarthrosis and non-union by reproducing the beneficial properties of autologous bone grafting while restricting its disadvantages.

Plasma-fibroblast gel as scaffold for islet transplantation.

The transplant of pancreatic islets into the liver can restore normal blood glucose levels in patients with type I diabetes. However, long-term results have indicated that the site and method of transplantation still need to be optimized to improve islet engraftment. This study was designed to assess the efficiency of the use of clotted blood plasma containing fibroblasts ("plasma-fibroblast gel") as a scaffold for subcutaneous islet transplantation in diabetic athymic mice. Islets embedded in the plasma-fibroblast gel were able to resolve hyperglycemia in transplanted mice, restoring normoglycemia over a 60-day period and allowing gradual body weight recovery. Glucose clearances were significantly improved when compared to those recorded in diabetic animals and similar to those observed in the control group (free islets transplanted beneath the kidney capsule). Histological evaluation revealed functional islets within a subcutaneous tissue rich in collagen fibers that was well vascularized, with blood vessels observed around and inside the islets. These findings suggest that this approach could be used as an alternative option for the treatment of type I diabetes in human clinical practice.