Emerging technologies in the delivery of erythropoietin for therapeutics.

Deciphering the function of proteins and their roles in signaling pathways is one of the main goals of biomedical research, especially from the perspective of uncovering pathways that may ultimately be exploited for therapeutic benefit. Over the last half century, a greatly expanded understanding of the biology of the glycoprotein hormone erythropoietin (Epo) has emerged from regulator of the circulating erythrocyte mass to a widely used therapeutic agent. Originally viewed as the renal hormone responsible for erythropoiesis, recent in vivo studies in animal models and clinical trials demonstrate that many other tissues locally produce Epo independent of its effects on red blood cell mass. Thus, not only its hematopoietic activity but also the recently discovered nonerythropoietic actions in addition to new drug delivery systems are being thoroughly investigated in order to fulfill the specific Epo release requirements for each therapeutic approach. The present review focuses on updating the information previously provided by similar reviews and recent experimental approaches are presented to describe the advances in Epo drug delivery achieved in the last few years and future perspectives.

Epo delivery by genetically engineered C2C12 myoblasts immobilized in microcapsules.

ver the last half century, the use of erythropoietin (Epo) in the management of malignancies has been extensively studied. Originally viewed as the renal hormone responsible for red blood cell production, many recent in vivo and clinical approaches demonstrate that various tissues locally produce Epo in response to physical or metabolic stress. Thus, not only its circulating erythrocyte mass regulator activity but also the recently discovered nonhematological actions are being thoroughly investigated in order to fulfill the specific Epo delivery requirements for each therapeutic approach.

Aplicación y seguimiento del tratamiento del dolor neuropático periférico con capsaicina 179 mg realizado por enfermeras / Application and follow-up of the peripheral neuropathic pain treatment with capsaicin 179 mg conducted by nurses

Objetivo: evaluar la efectividad del tratamiento con parches de capsaicina 179 mg en personas con dolor neuropático periférico aplicado y en seguimiento realizado por enfermeras. Método: serie de casos longitudinal retrospectiva efectuada en la Unidad de Dolor del Hospital Universitario Son Llàtzer (Palma) entre 2018 y 2020. La población de estudio fue de 163 personas con ese tratamiento. Se llevó a cabo medición basal al mes, a los tres y a los seis meses. Se midieron sexo, edad, tiempo de evolución, aplicaciones realizadas, mejora en intensidad (NPRS: 0 a 10 puntos) y extensión del dolor, calidad de vida relacionada con la salud (EQ-5D-3L: 0 peor a 1 mejor), impresión de mejoría global del paciente (PGI-I: mejora; empeora o no mejora), uso de fármacos adyuvantes y efectos secundarios. Se llevó a cabo estadística descriptiva. Resultados: se incluyeron 133 pacientes con registros completos (= 57 años; = 30,2 meses de evolución; = 1,6 aplicaciones por persona). Se redujo la zona de dolor [Sí reduce (Mes 1: 67%; Mes 3: 41%; Mes 6: 20%)] y la intensidad del dolor pasó de = 7,35 a 6,32 al sexto mes. La calidad de vida fue superior a la media basal (0,37 sobre 1) en todas las mediciones. Mejoró la PGI [Mejora (Mes 1: 64,6%: Mes 3: 58,9%; Mes 6: 53,6 %)]. Disminuyó el uso de medicación adyuvante [Sí reduce (Mes 1: 28%; Mes 3: 30%; Mes 6: 67%)]. Los efectos adversos fueron dolor (78,9%), eritema (67,7%) y prurito (63,9%). Conclusión: el tratamiento aplicado por enfermeras fue eficaz y seguro. El seguimiento debe ser prolongado para detectar necesidades y cambios.(AU)

Objective: to evaluate the efficacy of the treatment with capsaicin 179mg patches applied and on follow-up by nurses in persons with peripheral neuropathic pain. Method: a longitudinal retrospective series of cases conducted at the Pain Unit of the Hospital Universitario Son Llàtzer between 2018 and 2020. The study population consisted of 196 persons with that treatment. Basal measurement was conducted at one month, at three and six months. The following were measured: gender, age, time of evolution, applications conducted, improvement in intensity (NPRS scale: 0 to 10 points) and extent of pain, health-related quality of life (EQ-5D-3L: 0=the worst to 1=the best), patient global impression of improvement (PGI-I: improvement, worsening or no improvement), use of adjuvant drugs and side effects. Descriptive statistics was applied. Results: 133 patients were included with complete records(= 57 years; = 30.2 months of evolution; = 1.6 applications per person). There was a reduction in the pain area [Reduced (Month 1: 67%; Month 3: 41%; Month 6: 20%)] and pain intensity moved from = 7.35 to 6.32 at month six. Quality of life was superior to the mean baseline (0.37 of 1) in all measurements. There was improvement in PGI [Improvement (Month 1: 64.6%: Month 3: 58.9%; Month 6: 53.6 %)]. There was a reduction in the use of adjuvant medication [Reduced (Month 1: 28%; Month 3: 30%; Month 6: 67%)]. The adverse effects were pain (78.9%), erythema (67.7%) and itching (63.9%). Conclusion: the treatment applied by nurses was effective and safe. There must be follow-up at long term in order to detect any needs and changes.(AU)

Stem cells in alginate bioscaffolds.

The immobilization of cells into polymeric scaffolds releasing therapeutic factors, such as alginate microcapsules, has been widely employed as a drug-delivery system for numerous diseases for many years. As a result of the potential benefits stem cells offer, during recent decades, this type of cell has gained the attention of the scientific community in the field of cell microencapsulation technology and has opened many perspectives. Stem cells represent an ideal tool for cell immobilization and so does alginate as a biomaterial of choice in the elaboration of these biomimetic scaffolds, offering us the possibility of benefiting from both disciplines in a synergistic way. This review intends to give an overview of the many possibilities and the current situation of immobilized stem cells in alginate bioscaffolds, showing the diverse therapeutic applications they can already be employed in; not only drug-delivery systems, but also tissue engineering platforms.

A perspective on bioactive cell microencapsulation.

Bioactive cell encapsulation has emerged as a promising tool for the treatment of patients with various disorders including diabetes mellitus, central nervous system diseases, and cardiovascular diseases. The implantation of encapsulated cells that secrete a therapeutic product (protein, peptide, or antibody) within a semipermeable membrane provides a physical barrier to mask the implant from immune surveillance at a local level without the need for systemic immunosuppression; this serves to achieve a successful therapeutic function following in vivo implantation. The aim of this review article is to provide an update on the progress in this field. The current state of cell encapsulation technology as a controlled drug delivery system will be covered in detail, and the essential requirements of the technology, the challenges, and the future directions under investigation will be highlighted. The technical and biological advances, together with the increasing experience in the field, may lead to the realization of the full potential of bioactive cell encapsulation in the coming years.

Design of a composite drug delivery system to prolong functionality of cell-based scaffolds.

Cell encapsulation technology raises hopes in medicine and biotechnology. However, despite important advances in the field in the past three decades, several challenges associated with the biocompatibility are still remaining. In the present study, the effect of a temporary release of an anti-inflammatory agent on co-administered encapsulated allogeneic cells was investigated. The aim was to determine the biocompatibility and efficacy of the approach to prevent the inflammatory response. A composite delivery system comprised of alginate-poly-l-lysine-alginate (APA)-microencapsulated Epo-secreting myoblasts and dexamethasone (DXM)-releasing poly(lactic-co-glycolic acid) (PLGA) microspheres was implanted in the subcutaneous space of Balb/c mice for 45 days. The use of independently co-implanted DXM-loaded PLGA microspheres resulted in an improved functionality of the cell-based graft, evidenced by significantly higher hematocrit levels found in the cell-implanted groups by day 45, which was found to be more pronounced when higher cell-doses (100 µL) were employed. Moreover, no major host reaction was observed upon implantation of the systems, showing good biocompatibility and capability to partially avoid the inflammatory response, probably due to the immunosuppressive effects related to DXM. The findings of this study imply that DXM-loaded PLGA microspheres show promise as release systems to enhance biocompatibility and offer advantage in the development of long-lasting and effective implantable microencapsulated cells by generating a potential immunopriviledged local environment and an effective method to limit the structural ensheathing layer caused by inflammation.

Recent advances in the use of encapsulated cells for effective delivery of therapeutics.

Cell encapsulation can be defined as a living cell approach for the long-term delivery of therapeutic products. It consists of the immobilization of therapeutically active cells within a general polymer matrix that permits the ingress of nutrients and oxygen and the egress of therapeutic protein products but impedes the immune contact of the enclosed cells. In recent decades many attempts have evaluated the potential of this technology to release therapeutic agents for the treatment of different pathologies and disorders. At present, cell encapsulation may be used as a technological platform to improve knowledge and clinical use of stem cells. This review describes the main issues related to this cell-based approach and summarizes some of the most interesting therapeutic applications.

Microcapsules and microcarriers for in situ cell delivery.

In recent years, the use of transplanted living cells pumping out active factors directly at the site has proven to be an emergent technology. However a recurring impediment to rapid development in the field is the immune rejection of transplanted allo- or xenogeneic cells. Immunosuppression is used clinically to prevent rejection of organ and cell transplants in humans, but prolonged usage can make the recipient vulnerable to infections, and increase the likelihood of tumorigenesis of the transplanted cells. Cell microencapsulation is a promising tool to overcome these drawbacks. It consists of surrounding cells with a semipermeable polymeric membrane. The latter permits the entry of nutrients and the exit of therapeutic protein products, obtaining in this way a sustained delivery of the desirable molecule. The membrane isolates the enclosed cells from the host immune system, preventing the recognition of the immobilization cells as foreign. This review paper intends to overview the current situation in the cell encapsulation field and discusses the main events that have occurred along the way. The technical advances together with the ever increasing knowledge and experience in the field will undoubtedly lead to the realization of the full potential of cell encapsulation in the future.

Cryopreservation based on freezing protocols for the long-term storage of microencapsulated myoblasts.

One important challenge in biomedicine is the ability to cryogenically preserve not only cells, but also tissue-engineered constructs. In the present paper, alginate-poly-l-lysine-alginate (APA) microcapsules containing erythropoietin (Epo)-secreting C(2)C(12) myoblasts were elaborated, characterized and tested both in vitro and in vivo. Dimethylsulfoxide (DMSO) was selected as cryoprotectant to evaluate the maintenance of physiological activity of cryopreserved microencapsulated myoblasts employing procedures based on freezing protocols up to a 45-day cryopreservation period. High chemical resistance of the cryopreserved microcapsules was observed using 10% DMSO as cryoprotectant following a standard slow-cooling procedure. Although a 42% reduction in Epo release from the microencapsulated cells was observed in comparison with the non-cryopreserved group, the in vivo biocompatibility and functionality of the encapsulated cells subcutaneously implanted in Balb/c mice was corroborated by high and sustained hematocrit levels over 194 days and lacking immunosuppressive protocols. No major host reaction was observed. Based on the results obtained in our study, a slow-cooling protocol using 10% DMSO as cryoprotectant (confirmed for cryopreservation periods up to 45 days) might be considered a suitable therapeutic strategy if the long-term storage of microencapsulated cells, such as C(2)C(12) myoblasts is pretended.

Xenogeneic transplantation of erythropoietin-secreting cells immobilized in microcapsules using transient immunosuppression.

Cell encapsulation technology holds promise for the sustained and controlled delivery of therapeutic proteins such as erythropoietin (Epo). Transplantation of microencapsulated C(2)C(12) myoblasts in syngeneic and allogeneic recipients has been proven to display long-term survival when implanted subcutaneously. However, xenotransplantation approaches may be affected by the rejection of the host and thus may require transient immunosuppression. C(2)C(12) myoblasts genetically engineered to secrete murine Epo (mEpo) were encapsulated in alginate-poly-L-lysine-alginate (APA) microcapsules and implanted subcutaneously in Fischer rats using a transient immunosuppressive FK-506 therapy (2 or 4 weeks) to ameliorate immunoprotection of microcapsules. Rats receiving short-term immunosupression with FK-506 maintained high hematocrit levels for a longer period of time (14 weeks) in comparison with the non-immunosuppressed group. In addition, a significant difference in hematocrit levels was detected by day 65 among rats immunosuppressed for 2 or 4 weeks, corroborating the need of a minimum period of immunosuppression (4 weeks) for this purpose. These results highlight the importance of applying a minimum period (4 weeks) of transient immunosuppression if the host acceptance of xenogeneic implants based on microencapsulated Epo-secreting cells is aimed.

Cell microencapsulation technology: towards clinical application.

The pharmacokinetic properties of a drug can be significantly improved by the delivery process. Scientists have understood that developing suitable drug delivery systems that release the therapeutically active molecule at the level and dose it is needed and during the optimal time represents a major advance in the field. Cell microencapsulation is an alternative approach for the sustained delivery of therapeutic agents. This technology is based on the immobilization of different types of cells within a polymeric matrix surrounded by a semipermeable membrane for the long-term release of therapeutics. As a result, encapsulated cells are isolated from the host immune system while allowing exchange of nutrients and waste and release of the therapeutic agents. The versatility of this approach has stimulated its use in the treatment of numerous medical diseases including diabetes, cancer, central nervous system diseases and endocrinological disorders among others. The aim of this review article is to give an overview on the current state of the art of the use of cell encapsulation technology as a controlled drug delivery system. The most important advantages of this type of "living" drug release strategy are highlighted, but also its limitations pointed out, and the major challenges to be addressed in the forthcoming years are described.

In vitro characterization and in vivo functionality of erythropoietin-secreting cells immobilized in alginate-poly-L-lysine-alginate microcapsules.

The in vitro and in vivo characterization of cell-loaded immobilization devices is an important challenge in cell encapsulation technology for the long-term efficacy of this approach. In the present paper, alginate-poly-l-lysine-alginate (APA) microcapsules containing erythropoietin (Epo)-secreting C2C12 myoblasts have been elaborated, characterized, and tested both in vitro and in vivo. High mechanical and chemical resistance of the elaborated microcapsules was observed. Moreover, the in vitro cultured encapsulated cells released 81.9 +/- 8.2 mIU/mL/24 h (by 100 cell-loaded microcapsules) by day 7, reaching the highest peak at day 21 (161.7 +/- 0.9 mIU/mL/24 h). High and constant hematocrit levels were maintained over 120 days after a single subcutaneous administration of microcapsules and lacking immunosuppressive protocols. No major host reaction was observed. On the basis of the results obtained in our study, cell encapsulation technology might be considered a suitable therapeutic strategy for the long-term delivery of biologically active products, such as Epo.