One of the limitations in organ, tissue or cellular transplantations is graft rejection. To minimize or prevent this, recipients must make use of immunosuppressive drugs (IS) throughout their entire lives. However, its continuous use generally causes several side effects. Although some IS dose reductions and withdrawal strategies have been employed, many patients do not adapt to these protocols and must return to conventional IS use. Therefore, many studies have been carried out to offer treatments that may avoid IS administration in the long term. A promising strategy is cellular microencapsulation. The possibility of microencapsulating cells originates from the opportunity to use biomaterials that mimic the extracellular matrix. This matrix acts as a support for cell adhesion and the syntheses of new extracellular matrix self-components followed by cell growth and survival. Furthermore, by involving the cells in a polymeric matrix, the matrix acts as an immunoprotective barrier, protecting cells against the recipient’s immune system while still allowing essential cell survival molecules to diffuse bilaterally through the polymer matrix pores. In addition, this matrix can be associated with IS, thus diminishing systemic side effects. In this context, this review will address the natural biomaterials currently in use and their importance in cell therapy.

The term “liver disease” refers to any hepatic condition that leads to tissue damage or altered hepatic function and can be induced by virus infections, autoimmunity, inherited genetic mutations, high consumption of alcohol or drugs, fat accumulation, and cancer. Some types of liver diseases are becoming more frequent worldwide. This can be related to increasing rates of obesity in developed countries, diet changes, higher alcohol intake, and even the coronavirus disease 2019 (COVID-19) pandemic was associated with increased liver disease-related deaths. Although the liver can regenerate, in cases of chronic damage or extensive fibrosis, the recovery of tissue mass is impossible, and a liver transplant is indicated. Because of reduced organ availability, it is necessary to search for alternative bioengineered solutions aiming for a cure or increased life expectancy while a transplant is not possible. Therefore, several groups were studying the possibility of stem cells transplantation as a therapeutic alternative since it is a promising strategy in regenerative medicine for treating various diseases. At the same time, nanotechnological advances can contribute to specifically targeting transplanted cells to injured sites using magnetic nanoparticles. In this review, we summarize multiple magnetic nanostructure-based strategies that are promising for treating liver diseases.

Microencapsulation is a widely studied cell therapy and tissue bioengineering technique, since it is capable of creating an immune-privileged site, protecting encapsulated cells from the host immune system. Several polymers have been tested, but sodium alginate is in widespread use for cell encapsulation applications, due to its low toxicity and easy manipulation. Different cell encapsulation methods have been described in the literature using pressure differences or electrostatic changes with high cost commercial devices (about 30,000 US dollars). Herein, a low-cost device (about 100 US dollars) that can be created by commercial syringes or 3D printer devices has been developed. The capsules, whose diameter is around 500 µm and can decrease or increase according to the pressure applied to the system, is able to maintain cells viable and functional. The hydrogel porosity of the capsule indicates that the immune system is not capable of destroying host cells, demonstrating that new studies can be developed for cell therapy at low cost with microencapsulation production. This device may aid pre-clinical and clinical projects in low- and middle-income countries and is lined up with open source equipment devices.

Background: Acute liver failure (ALF) is a rare, yet potentially fatal clinical syndrome characterized by the rapid deterioration of hepatic function in individuals without pre-existing liver disease, typically occurring over a period of days to weeks. It is associated with substantial morbidity and mortality, particularly in low-income settings, and is clinically defined by the presence of jaundice, coagulopathy, and hepatic encephalopathy. Among its various etiologies, acetaminophen (APAP) overdose is the leading cause of drug-induced liver injury and ALF, especially in industrialized countries such as the United States and the United Kingdom. In the present study, we compared two experimental approaches for inducing APAP-mediated ALF in mice: oral and intraperitoneal (IP) administration. Methods: While most studies reported in the literature rely on a single route of administration, this comparative analysis provides a more comprehensive evaluation of the advantages and limitations associated with each method, thereby enhancing the reproducibility and translational relevance of experimental ALF models. Results: Our results demonstrate that both administration routes effectively recapitulate key clinical and biochemical features of human ALF, including hepatic encephalopathy, marked elevations in serum transaminases, and high mortality rates. However, the effective APAP dose required to achieve these outcomes differed between the two routes, with 400 mg/kg for IP administration and 500 mg/kg for oral administration, as would be expected based on pharmacokinetic considerations. From a clinical assessment perspective, the use of adapted scoring systems, such as the O’Grady criteria, is essential for evaluating encephalopathy in animal models. Notably, oral administration via gastric gavage requires greater technical expertise, which may influence experimental consistency. Conclusions: Taken together, these findings underscore the importance of route selection in experimental design and highlight the value of comparative approaches for optimizing preclinical models of ALF.