A Specialized Therapeutic Approach to Chronic Urticaria Refractory to H1-Antihistamines Improves Disease Burden: The Spanish AWARE Experience.

OBJECTIVE: During its first year, the AWARE study assessed disease activity, patient quality of life (QOL), and treatment patterns in chronic urticaria (CU) refractory to H1-antihistamines (H1-AH) in clinical practice. METHODS: We performed an observational, prospective (24 months), international, multicenter study. The inclusion criteria were age ≥18 years and H1-AH-refractory CU (>2 months). At each visit, patients completed questionnaires to assess disease burden (Urticaria Control Test [UCT]), disease activity (7 day-Urticaria Activity Score [UAS7]), and QOL (Dermatology Life Quality index [DLQI], Chronic Urticaria Quality of Life Questionnaire [CU-Q2oL], and Angioedema Quality of Life Questionnaire [AE-QoL]). We present data for Spain. RESULTS: The study population comprised 270 evaluable patients (73.3% female, mean [SD] age, 48.9 [14.7] years). At baseline, 89.3% were prescribed a CU treatment. After 1 year, first- and second-line treatments became less frequent and third-line treatments became more frequent. At baseline, 47.0% of patients experienced angioedema; at 1 year, this percentage had fallen to 11.8%. The mean (SD) AE-QoL score decreased from 45.2 (28.7) to 24.0 (25.8). The mean (SD) UCT score decreased from 7.0 (4.5) to 12.1 (4.1). According to UAS7, 38.2% of patients reported absence of wheals and itch in the previous 7 days at 1 year compared with 8.3% at baseline. The mean (SD) DLQI score decreased from 8.0 (7.4) to 2.8 (4.6). At the 1-year visit, the percentage of patients reporting a high or very high impact on QOL fell from 29.9% to 9.6%. CONCLUSION: H1-AH-refractory CU in Spain is characterized by absence of control of symptoms and a considerable impact on QOL. Continuous follow-up of CU patients and third-line therapies reduce disease burden and improve patients' QOL.

Pharmacokinetics of Benznidazole in Healthy Volunteers and Implications in Future Clinical Trials.

Despite its toxicity and low efficacy in the chronic phase, benznidazole is the drug of choice in Chagas disease. Scarce information about pharmacokinetics and pharmacodynamics of benznidazole has been published. We performed a phase I, open-label, nonrandomized pharmacokinetic study of benznidazole (Abarax) conducted with 8 healthy adult volunteers at the Infectious Diseases Department of the Vall d'Hebron University Hospital (Barcelona, Spain). The separation and detection of benznidazole were performed on a Waters Acquity ultraperformance liquid chromatography system (UPLC) coupled with a Waters Xevo TQ MS triple quadrupole mass spectrometer. The pharmacokinetic parameters were calculated based on a noncompartmental body model using Phoenix WinNonlin version 6.3 software. Furthermore, computational simulations were calculated for the multiple-dose administration at two dose regimens: 100 mg of benznidazole administered every 8 h and 150 mg of benznidazole administered every 12 h. After benznidazole administration, the median area under the concentration-time curve from time zero to time t (AUC0-t ) and extrapolated to infinity (AUC0-∞) were about 46.4 µg · h/ml and 48.4 µg · h/ml, respectively. Plasma benznidazole concentrations peaked at 3.5 h, with maximal concentrations of 2.2 µg/ml, and benznidazole exhibited a terminal half-life of 12.1 h. The median maximum concentration (Cmax) of benznidazole was lower in men than in women (1.6 versus 2.9 µg/ml), and median volume of distribution (V) as a function of bioavailability (F) was higher in men than in women (125.9 versus 88.6 liters). In conclusion, dose regimens (150 mg/12 h or 100 mg/8 h) reached a steady-state range concentration above of the minimum experimental therapeutic dose. Sex differences in the benznidazole pharmacokinetics were observed; mainly, men had lower Cmax and higher V/F than women.

Stability study of sodium colistimethate-loaded lipid nanoparticles.

In the last decades, the encapsulation of antibiotics into nanoparticulate carriers has gained increasing attention for the treatment of infectious diseases. Sodium colistimethate-loaded solid lipid nanoparticles (Colist-SLNs) and nanostructured lipid carriers (Colist-NLCs) were designed aiming to treat the pulmonary infection associated to cystic fibrosis patients. The nanoparticles were freeze-dried using trehalose as cryoprotectant. The stability of both nanoparticles was analysed over one year according to the International Conference of Harmonisation (ICH) guidelines by determining the minimum inhibitory concentration (MIC) against clinically isolated Pseudomonas aeruginosa strains and by studying their physico-chemical characteristics. The results showed that Colist-SLNs lost their antimicrobial activity at the third month; on the contrary, the antibacterial activity of Colist-NLCs was maintained throughout the study within an adequate range (MIC ≤16 µg/mL). In addition, Colist-NLCs exhibited suitable physico-chemical properties at 5 °C and 25 °C/60% relative humidity over one year. Altogether, Colist-NLCs proved to have better stability than Colist-SLNs.

Pulmonary drug delivery: a review on nanocarriers for antibacterial chemotherapy.

As the WHO stated, lower respiratory infections are the third leading cause of death. In addition, it is remarkable that antimicrobial resistance represents a huge threat. Thus, new therapeutic weapons are required. Among the possible alternatives, antibiotic encapsulation in nanoparticles has gained much attention in terms of improved tolerability, activity and ability to combat the resistance mechanisms of bacteria. In this regard, this review article focuses on the latest nanocarrier approaches for inhalatory therapy of antibiotics. First, the technology related to lung disposition will be reviewed. Then, nanocarrier systems will be introduced and the challenges required to perform adequate pulmonary deposition analysed. In the following part, drug delivery systems (DDSs) on the market or in clinical trials are described and, finally, new approaches of nanoparticles that have reached pre-clinical stage are enumerated. Altogether, this review aims at gathering together the novel nanosystems for anti-infectious therapy, underlining the potential of DDSs to improve and optimize currently available antibiotic therapies in the context of lung infections.

Protamine/DNA/Niosome Ternary Nonviral Vectors for Gene Delivery to the Retina: The Role of Protamine.

The present study aimed to evaluate the incorporation of protamine into niosome/DNA vectors to analyze the potential application of this novel ternary formulation to deliver the pCMS-EGFP plasmid into the rat retina. Binary vectors based on niosome/DNA and ternary vectors based on protamine/DNA/niosomes were prepared and physicochemically characterized. In vitro experiments were performed in ARPE-19 cells. At 1:1:5 protamine/DNA/niosome mass ratio, the resulted ternary vectors had 150 nm size, positive charge, spherical morphology, and condensed, released, and protected the DNA against enzymatic digestion. The presence of protamine in the ternary vectors improved transfection efficiency, cell viability, and DNA condensation. After ocular administration, the EGFP expression was detected in different cell layers of the retina depending on the administration route without any sign of toxicity associated with the formulations. While subretinal administration transfected mainly photoreceptors and retinal pigment epithelial cells at the site of injection, intravitreal administration produced a more uniform distribution of the protein expression through the inner layers of the retina. The protein expression in the retina persisted for at least one month after both administrations. Our study highlights the flattering properties of protamine/DNA/niosome ternary vectors for efficient and safe gene delivery to the rat retina.

Niosomes based on synthetic cationic lipids for gene delivery: the influence of polar head-groups on the transfection efficiency in HEK-293, ARPE-19 and MSC-D1 cells.

We designed niosomes based on three lipids that differed only in the polar-head group to analyze their influence on the transfection efficiency. These lipids were characterized by small-angle X-ray scattering before being incorporated into the niosomes which were characterized in terms of pKa, size, zeta potential, morphology and physical stability. Nioplexes were obtained upon the addition of a plasmid. Different ratios (w/w) were selected to analyze the influence of this parameter on size, charge and the ability to condense, release and protect the DNA. In vitro transfection experiments were performed in HEK-293, ARPE-19 and MSC-D1 cells. Our results show that the chemical composition of the cationic head-group clearly affects the physicochemical parameters of the niosomes and especially the transfection efficiency. Only niosomes based on cationic lipids with a dimethyl amino head group (lipid 3) showed a transfection capacity when compared with their counterparts amino (lipid 1) and tripeptide head-groups (lipid 2). Regarding cell viability, we clearly observed that nioplexes based on the cationic lipid 3 had a more deleterious effect than their counterparts, especially in ARPE-19 cells at 20/1 and 30/1 ratios. Similar studies could be extended to other series of cationic lipids in order to progress in the research on safe and efficient non-viral vectors for gene delivery purposes.

[Neonatal seizures and progression to epilepsy in a tertiary hospital]. / Crisis neonatales y evolución a epilepsia en un hospital de tercer nivel.

INTRODUCTION: Given the immaturity of the newborn, neonatal seizures are a diagnostic challenge. Most of them are secondary to an acute event. A small percentage constitute the onset of epilepsy. AIMS: The aim was to analyse neonates with a diagnosis of seizures admitted to a tertiary hospital between November 2009 and May 2021, and their subsequent progression to epilepsy. MATERIAL AND METHODS: A retrospective observational study was carried out using the hospital database. Information was collected on neonates with a discharge diagnosis of 'seizures' or 'moderate or severe hypoxic-ischaemic encephalopathy'. Different variables were analysed: aetiology of the seizures, type, persistence over time, treatment and electroclinical correlates. RESULTS: Of 165 patients, 55 presented neonatal seizures. As regards aetiology, 43 patients (78%) had seizures secondary to an acute event, of which 19 (34%) were hypoxic-ischaemic encephalopathies, and 22 (40%) had other acute disorders. Genetic alteration was found in six of them (11%). Thirteen patients (24%) progressed to subsequent epilepsy, of whom seven had symptomatic epilepsy, with a period of latency after the acute event in two patients. Six patients had neonatal epilepsy with unprovoked seizures. Twenty-two (62%) showed electroclinical correlates. All of the confirmed crises (100%) were focal. All the seizures were treated. The drug of choice was phenobarbital. CONCLUSIONS: Diagnosis of neonatal seizures requires high clinical suspicion and electroclinical confirmation. Most of them progress favourably, but a percentage constitute the onset of epilepsy, the identification of which will determine their therapeutic management.

TITLE: Crisis neonatales y evolución a epilepsia en un hospital de tercer nivel.Introducción. Las convulsiones neonatales son un reto diagnóstico, dada la inmadurez del recién nacido. La mayoría son secundarias a un evento agudo. Un pequeño porcentaje constituye el inicio de una epilepsia. Objetivos. Analizar a los neonatos ingresados en un hospital de tercer nivel con diagnóstico de crisis entre noviembre de 2009 y mayo de 2021, y su evolución posterior a epilepsia. Material y métodos. Se ha realizado un estudio observacional retrospectivo utilizando la base de datos del hospital. Se ha recogido la información de los neonatos con diagnóstico en el alta de 'convulsiones' o 'encefalopatía hipóxico-isquémica moderada o grave'. Se analizaron distintas variables: etiología de las crisis, tipo, persistencia temporal, tratamiento y correlato electroclínico. Resultados. De 165 pacientes, 55 presentaron crisis neonatales. En cuanto a la etiología, 43 pacientes (78%) tuvieron crisis secundarias a un evento agudo, de las cuales 19 (34%) fueron encefalopatías hipóxico-isquémicas, y 22 (40%), otras alteraciones agudas. En seis (11%) se encontró alteración genética. Trece pacientes (24%) evolucionaron a una epilepsia posterior, de los cuales siete presentaron una epilepsia sintomática, con un período de latencia tras el evento agudo en dos pacientes. Seis pacientes tuvieron epilepsia neonatal con crisis no provocadas. Veintidós (62%) mostraron correlato electroclínico. El 100% de las crisis confirmadas fueron focales. Todas las crisis se trataron. El fármaco de elección fue el fenobarbital. Conclusiones. El diagnóstico de convulsiones neonatales requiere una alta sospecha clínica y una confirmación electroclínica. La mayoría tiene evolución favorable, pero un porcentaje constituye el inicio de una epilepsia, cuya identificación determinará su manejo terapéutico.

Bioinspired gelatin/bioceramic composites loaded with bone morphogenetic protein-2 (BMP-2) promote osteoporotic bone repair.

There are currently several commercialized products approved by the Food and Drug Administration and the European Medicines Agency based on the use of recombinant human BMP-2 for the treatment of non-unions long fractures and spinal fusion. However, the adverse effects recorded with the use of BMPs suggest the need for drug delivery carriers that allow reducing the required doses and improve their cost-effectiveness. Herein, we have developed a new osteoconductive scaffold that reduces the required doses of BMP-2 for promoting bone regeneration in an osteoporotic defect model. The composite is, in brief, a gelatin-based 3D scaffold reinforced with either calcium sulfate or hydroxyapatite as an inorganic osteoconductive biomaterial. To this end, the organic/inorganic composite systems showed high hydration capacity and good in vitro degradability. The incorporation of 7.5% (m/v) ceramic compounds resulted in scaffolds with stiffer Young modulus (179 and 75 kPa for CaSO4_7 and HA_7, respectively) than bare gelatin hydrogels (48 kPa). Studies with human bone-marrow derived mesenchymal stem cells (hBM-MSCs) revealed that the 3D scaffolds promote cell adhesion and proliferation along with osteogenic differentiation capabilities. Specifically, downregulation of stemness (Nanog, Oct4) genes and upregulation of osteogenic markers (ALP, Col1a1, Fmod) by two fold were observed over 10 days under basal culture conditions. Promisingly, the sustained in vitro release of BMP-2 observed from the porous reinforced scaffolds allowed us to address the critical-sized osteoporotic mice calvarial defects with a relatively low growth factor doses (600 ng BMP-2/scaffold) compared to conventional doses at 2-15 micrograms. Overall, this study demonstrates the promising potential of osteoconductive gelatin/calcium bioceramics composites as osteogenic growth factors delivery carriers for bone-regeneration via ultra-low growth factor doses.

Biomaterial-based technologies for brain anti-cancer therapeutics and imaging.

Treating malignant brain tumors represents one of the most formidable challenges in oncology. Contemporary treatment of brain tumors has been hampered by limited drug delivery across the blood-brain barrier (BBB) to the tumor bed. Biomaterials are playing an increasingly important role in developing more effective brain tumor treatments. In particular, polymer (nano)particles can provide prolonged drug delivery directly to the tumor following direct intracerebral injection, by making them physiochemically able to cross the BBB to the tumor, or by functionalizing the material surface with peptides and ligands allowing the drug-loaded material to be systemically administered but still specifically target the tumor endothelium or tumor cells themselves. Biomaterials can also serve as targeted delivery devices for novel therapies including gene therapy, photodynamic therapy, anti-angiogenic and thermotherapy. Nanoparticles also have the potential to play key roles in the diagnosis and imaging of brain tumors by revolutionizing both preoperative and intraoperative brain tumor detection, allowing early detection of pre-cancerous cells, and providing real-time, longitudinal, non-invasive monitoring/imaging of the effects of treatment. Additional efforts are focused on developing biomaterial systems that are uniquely capable of delivering tumor-associated antigens, immunotherapeutic agents or programming immune cells in situ to identify and facilitate immune-mediated tumor cell killing. The continued translation of current research into clinical practice will rely on solving challenges relating to the pharmacology of nanoparticles but it is envisioned that novel biomaterials will ultimately allow clinicians to target tumors and introduce multiple, pharmaceutically relevant entities for simultaneous targeting, imaging, and therapy in a unique and unprecedented manner.

Design and characterization of calcium alginate microparticles coated with polycations as protein delivery system.

Bovine serum albumin (BSA) loaded calcium alginate microparticles (MPs) produced in this study by a w/o emulsification and external gelation method exhibited spherical and fairly smooth and porous morphology with 1.052 ± 0.057 µm modal particle size. The high permeability of the calcium alginate hydrogel lead to a potent burst effect and too fast protein release. To overcome these problems, MPs were coated with polycations, such as chitosan, poly-L-lysine and DEAE-dextran. Our results demonstrated that coated MPs showed slower release and were able to significantly reduce the release of BSA in the first hour. Therefore, this method can be applied to prepare coated alginate MPs which could be an optimal system for the controlled release of biotherapeutic molecules. Nevertheless, further studies are needed to optimize delivery properties which could provide a sustained release of proteins.

Development, characterization and sterilisation of Nanocellulose-alginate-(hyaluronic acid)- bioinks and 3D bioprinted scaffolds for tissue engineering.

3D-bioprinting is an emerging technology of high potential in tissue engineering (TE), since it shows effective control over scaffold fabrication and cell distribution. Biopolymers such as alginate (Alg), nanofibrillated cellulose (NC) and hyaluronic acid (HA) offer excellent characteristics for use as bioinks due to their excellent biocompatibility and rheological properties. Cell incorporation into the bioink requires sterilisation assurance, and autoclave, ß-radiation and γ-radiation are widely used sterilisation techniques in biomedicine; however, their use in 3D-bioprinting for bioinks sterilisation is still in their early stages. In this study, different sterilisation procedures were applied on NC-Alg and NC-Alg-HA bioinks and their effect on several parameters was evaluated. Results demonstrated that NC-Alg and NC-Alg-HA bioinks suffered relevant rheological and physicochemical modifications after sterilisation; yet, it can be concluded that the short cycle autoclave is the best option to sterilise both NC-Alg based cell-free bioinks, and that the incorporation of HA to the NC-Alg bioink improves its characteristics. Additionally, 3D scaffolds were bioprinted and specifically characterized as well as the D1 mesenchymal stromal cells (D1-MSCs) embedded for cell viability analysis. Notably, the addition of HA demonstrates better scaffold properties, together with higher biocompatibility and cell viability in comparison with the NC-Alg scaffolds. Thus, the use of MSCs containing NC-Alg based scaffolds may become a feasible tissue engineering approach for regenerative medicine.

[Psoriatic arthritis and etanercept]. / Artritis psoriásica y etanercept.

Psoriatic arthritis (PA) is a chronic inflammatory condition whose symptoms generally appear after the skin symptoms. Making an early diagnosis and treatment of the disease is of vital importance because of the potential development of mutilating and deforming arthritis. Classical treatments of PA include the use of non-steroid anti-inflammatory drugs, disease-modifying antirheumatic drugs (DMARD) such as methotrexate, sulfasalazine, or gold, and finally, leflunomide. Research on the pathophysiology of psoriasis and of the PA has led to the incorporation of biological treatments, specifically anti-TNF drugs. The three treatments used most in PA are etanercept, infliximab and adalimumab. Of all these, we are going to make a systematic review of the principal studies available on etanercept for the treatment of PA.

Cutaneous expression of systemic candidiasis.

Skin lesions associated with Candida septicaemia occur only in a minority of patients, who are usually immunocompromised, but they can help to establish a diagnosis rapidly. The lesions form a characteristic maculopapular or nodular rash at the onset of the infection. We report three cases of systemic candidiasis (SC) with cutaneous manifestations in immunocompromised patients. In these patients, the lesions started as asymptomatic or slightly pruriginous macules, papules or nodules localized on the trunk and extremities. The patients' general condition was very poor and they presented a high fever at the onset of the illness. Candida spp. were isolated from blood in all cases, and histology showed yeasts in two of them. Most of the lesions resolved with antifungal treatment. The diagnosis of SC is often delayed or missed because of the absence of useful diagnostic tools, the varying clinical manifestations and the frequent negativity (50-75%) of blood cultures for Candida. Fluconazole is the treatment of choice for Candida albicans, but treatment response is unknown for other Candida spp., which may require treatment with amphotericin B.

Cell Microencapsulation and Cryopreservation with Low Molecular Weight Hyaluronan and Dimethyl Sulfoxide.

Cryopreservation is commonly used for the storage of cells, tissues, organs or 3D cell-based products using ultra-low temperatures, which involves the immersion in liquid nitrogen for their long-term preservation. The cryopreservation of several microencapsulated cells is usually performed by the slow freezing with the dimethyl sulfoxide (DMSO) as a cryoprotectant agent (CPA). In this study, we cryopreserved several microencapsulated cells with the natural, non-toxic low molecular-weight hyaluronan (LMW-HA) at 5% and DMSO 10% solution assessing cell viability and metabolic activity after thawing. The cryopreservation of microencapsulated D1 mesenchymal stem cells (D1MSC) and murine myoblast cells (C2C12) with the LMW-HA 5% presented similar outcomes after thawing compared to the DMSO solution, showing the low molecular weight hyaluronan as a natural, non-toxic CPA that can be used preventing the DMSO related adverse effects after the implantation of the cryopreserved cell-based products.

Type 1 Diabetes Mellitus reversal via implantation of magnetically purified microencapsulated pseudoislets.

Microencapsulation of pancreatic islets for the treatment of Type I Diabetes Mellitus (T1DM) generates a high quantity of empty microcapsules, resulting in high therapeutic graft volumes that can enhance the host's immune response. We report a 3D printed microfluidic magnetic sorting device for microcapsules purification with the objective to reduce the number of empty microcapsules prior transplantation. In this study, INS1E pseudoislets were microencapsulated within alginate (A) and alginate-poly-L-lysine-alginate (APA) microcapsules and purified through the microfluidic device. APA microcapsules demonstrated higher mechanical integrity and stability than A microcapsules, showing better pseudoislets viability and biological function. Importantly, we obtained a reduction of the graft volume of 77.5% for A microcapsules and 78.6% for APA microcapsules. After subcutaneous implantation of induced diabetic Wistar rats with magnetically purified APA microencapsulated pseudoislets, blood glucose levels were restored into normoglycemia (<200 mg/dL) for almost 17 weeks. In conclusion, our described microfluidic magnetic sorting device represents a great alternative approach for the graft volume reduction of microencapsulated pseudoislets and its application in T1DM disease.

Solid lipid nanoparticles for retinal gene therapy: transfection and intracellular trafficking in RPE cells.

Retinal pigment epithelial (RPE) cells are usually employed to study DNA systems for diseases related to problems in the retina. Solid lipid nanoparticles (SLNs) have been shown to be useful non-viral vectors for gene therapy. The objective of this work was to evaluate the transfection capacity of SLNs in the human retinal pigment epithelial established cell line (ARPE-19) in order to elucidate the potential application of this vector in the treatment of retinal diseases. Results showed a lower transfection level of SLNs in ARPE-19 cells than in HEK293 (2.5% vs. 14.9% EGFP positive cells at 72h post-transfection). Trafficking studies revealed a delay in cell uptake of the vectors in ARPE-19 cells. Differences in internalization process into the two cell lines studied explain, in part, the difference in the gene expression. The clathrin-mediated endocytosis in ARPE-19 cells directs the solid lipid nanoparticles to lysosomes; moreover, the low division rate of this cell line hampers the entrance of DNA into the nucleus. The knowledge of intracellular trafficking is very useful in order to design more efficient vectors taking into account the characteristics of the specific cell line to be transfected.

Low molecular-weight hyaluronan as a cryoprotectant for the storage of microencapsulated cells.

The low-temperature storage of therapeutic cell-based products plays a crucial role in their clinical translation for the treatment of diverse diseases. Although dimethylsulfoxide (DMSO) is the most successful cryoprotectant in slow freezing of microencapsulated cells, it has shown adverse effects after cryopreserved cell-based products implantation. Therefore, the search of alternative non-toxic cryoprotectants for encapsulated cells is continuously investigated to move from bench to the clinic. In this work, we investigated the low molecular-weight hyaluronan (low MW-HA), a natural non-toxic and non-sulfated glycosaminoglycan, as an alternative non-permeant cryoprotectant for the slow freezing cryopreservation of encapsulated cells. Cryopreservation with low MW-HA provided similar metabolic activity, cell dead and early apoptotic cell percentage and membrane integrity after thawing, than encapsulated cells stored with either DMSO 10% or Cryostor 10. However, the beneficial outcomes with low MW-HA were not comparable to DMSO with some encapsulated cell types, such as the human insulin secreting cell line, 1.1B4, maybe explained by the different expression of the CD44 surface receptor. Altogether, we can conclude that low MW-HA represents a non-toxic natural alternative cryoprotectant to DMSO for the cryopreservation of encapsulated cells.

Engineering a Clinically Translatable Bioartificial Pancreas to Treat Type I Diabetes.

Encapsulating, or immunoisolating, insulin-secreting cells within implantable, semipermeable membranes is an emerging treatment for type 1 diabetes. This approach can eliminate the need for immunosuppressive drug treatments to prevent transplant rejection and overcome the shortage of donor tissues by utilizing cells derived from allogeneic or xenogeneic sources. Encapsulation device designs are being optimized alongside the development of clinically viable, replenishable, insulin-producing stem cells, for the first time creating the possibility of widespread therapeutic use of this technology. Here, we highlight the status of the most advanced and widely explored implementations of cell encapsulation with an eye toward translating the potential of this technological approach to medical reality.

Advances in the slow freezing cryopreservation of microencapsulated cells.

Over the past few decades, the use of cell microencapsulation technology has been promoted for a wide range of applications as sustained drug delivery systems or as cells containing biosystems for regenerative medicine. However, difficulty in their preservation and storage has limited their availability to healthcare centers. Because the preservation in cryogenic temperatures poses many biological and biophysical challenges and that the technology has not been well understood, the slow cooling cryopreservation, which is the most used technique worldwide, has not given full measure of its full potential application yet. This review will discuss the different steps that should be understood and taken into account to preserve microencapsulated cells by slow freezing in a successful and simple manner. Moreover, it will review the slow freezing preservation of alginate-based microencapsulated cells and discuss some recommendations that the research community may pursue to optimize the preservation of microencapsulated cells, enabling the therapy translate from bench to the clinic.