Nrf2 activation: a key mechanism in stem cell exosomes-mediated therapies

Exosomes are nano-sized membrane extracellular vesicles which can be released from various types of cells. Exosomes originating from inflammatory or injured cells can have detrimental effects on recipient cells, while exosomes derived from stem cells not only facilitate the repair and regeneration of damaged tissues but also inhibit inflammation and provide protective effects against various diseases, suggesting they may serve as an alternative strategy of stem cells transplantation. Exosomes have a fundamental role in communication between cells, through the transfer of proteins, bioactive lipids and nucleic acids (like miRNAs and mRNAs) between cells. This transfer significantly impacts both the physiological and pathological functions of recipient cells. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, is able to mitigate damage caused by oxidative stress and inflammation through various signaling pathways. The positive effects resulting from the activation of the Nrf2 signaling pathway in different disorders have been documented in various types of literature. Studies have confirmed that exosomes derived from stem cells could act as Nrf2 effective agonists. However, limited studies have explored the Nrf2 role in the therapeutic effects of stem cell-derived exosomes. This review provides a comprehensive overview of the existing knowledge concerning the role of Nrf2 signaling pathways in the impact exerted by stem cell exosomes in some common diseases.

Mitochondria-loaded alginate-based hydrogel accelerated angiogenesis in a rat model of acute myocardial infarction

Here, mitochondria were isolated from mesenchymal stem cells (MSCs) after being treated with mitochondria-stimulating substrates, 50 μM metformin (Met), and 40 μM dichloroacetic acid (DCA). The isolated mitochondria (2 × 107 particles) were characterized and encapsulated inside 100 μl hydrogel composed of alginate (3 % w/v; Alg)/gelatin (Gel; 1 % w/v) enriched with 1 μM pyrrole (Pyr) solidified in the presence of 0.2 M FeCl3. The physicochemical properties and cytocompatibility of prepared hydrogels were assessed using FTIR, swelling, biodegradation, porosity assays, and scanning electron microscopy (SEM). The mitochondria-bearing hydrogel was injected into the ischemic area of rat hearts. FTIR absorption bands represented that the addition of FeCl3 led to polypyrrole (PPy) formation, polysaccharide oxidation, and interaction between Alg and Gel. SEM images exhibited porous structure and the size of pores was reduced in Alg/Gel + PPy group compared to Alg + PPy hydrogel. Based on the data, both Alg + PPy and Alg/Gel + PPy hydrogels can preserve the integrity and morphology of loaded mitochondria. It was noted that Alg/Gel + PPy hydrogel possessed a higher swelling ratio, degradation, and porosity compared to Alg + PPy group. Data confirmed that Alg/Gel + PPy hydrogel containing 1 μM Pyr yielded the highest survival rate compared to groups with 2 and 4 μM Pyr (p < 0.05). Injection of mitochondria-loaded Alg/Gel + PPy hydrogel yielded significant restoration of left ventricle thickness compared to the infarction, mitochondria, and Alg/Gel + PPy hydrogel groups 14 days post-injection (p < 0.05). Histological analyses revealed a significant increase of vWF+ capillaries and α-SMA+ arterioles in the mitochondria-loaded Alg/Gel + PPy hydrogel group (p < 0.05). Immunofluorescence imaging revealed the ability of rat cardiomyocytes to uptake mitochondria alone or after being loaded into Alg/Gel + PPy hydrogel. These effects were evident in the Alg/Gel + PPy group. Taken together, electroconductive Alg-based hydrogels are suitable platforms for the transplantation of cells and organelles and the regeneration of ischemic heart changes.

Exosomes as Theranostic Agents in Reproduction System

Exosomes (Exos), belonging to extracellular vesicles, are cell-derived nano-sized vesicles with the potential to carry different kinds of biological molecules. Many studies have proved the impacts of exosomal cargo on several biological processes in female and male reproductive systems. It is also hypothesized that changes in exosomal cargo are integral to the promotion of certain pathological conditions, thus Exos can be used as valid biomarkers for the diagnosis of infertility and other abnormal conditions. Here, efforts are made to collect some recent data related to the physiological significance of Exos in the reproductive system, and their potential therapeutic effects. It is anticipated that the current review article will lay the groundwork for elucidating the source and mechanisms by which Exos control the reproductive system additionally supplying fresh methods and concepts for the detection and treatment of disorders associated with fertility for future studies.

Applications of engineered exosomes in drugging noncoding RNAs for cancer therapy

Noncoding RNAs (ncRNAs) are engaged in key cell biological and pathological events, and their expression alteration is connected to cancer progression both directly and indirectly. A huge number of studies have mentioned the significant role of ncRNAs in cancer prevention and therapy that make them an interesting subject for cancer therapy. However, there are several limitations, including delivery, uptake, and short half-life, in the application of ncRNAs in cancer treatment. Exosomes are introduced as promising options for the delivery of ncRNAs to the target cells. In this review, we will briefly discuss the application and barriers of ncRNAs. After that we will focus on exosome-based ncRNAs delivery and their advantages as well as the latest achievements in drugging ncRNAs with exosomes.

Novel Approaches Used in Ovarian Tissue Transplantation for Fertility Preservation: Focus on Tissue Engineering Approaches and Angiogenesis Capacity

Due to the impact of the modern lifestyle, female infertility has been reduced because of different reasons. For example, in combined chemotherapeutic therapies, a small fraction of cancer survivors has faced different post-complications and side effects such as infertility. Besides, in modern society, delayed age of childbearing has also affected fertility. Nowadays, ovarian tissue cryopreservation and transplantation (OTC/T) is considered one of the appropriate strategies for the restoration of ovarian tissue and bioactivity in patients with the loss of reproductive function. In this regard, several procedures have been considered to improve the efficacy and safety of OTT. Among them, a surgical approach is used to transplant ovaries into the optimal sites, but the existence of ischemic changes and lack of appropriate revascularization can lead to bulk follicular atresia. Besides, the role of OTC/T is limited in women of advanced maternal age undergoing lifesaving chemo-radiation. As a correlate, the development of de novo approaches with efficacious regenerative outcomes is highly welcomed. Tissue engineering shows high therapeutic potentialities to restore fertility in males and females using the combination of biomaterials, cells, and growth factors. Unfortunately, most synthetic and natural materials are at the experimental stage and only the efficacy has been properly evaluated in limited cases. Along with these descriptions, strategies associated with the induction of angiogenesis in transplanted ovaries can diminish the injuries associated with ischemic changes. In this review, the authors tried to summarize recent techniques, especially tissue engineering approaches for improving ovarian function and fertility by focusing on angiogenesis and neovascularization.

Melatonin and endothelial cell-loaded alginate-fibrin hydrogel promoted angiogenesis in rat cryopreserved/thawed ovaries transplanted to the heterotopic sites

BACKGROUND

Ischemic niche can promote follicular atresia following the transplantation of cryopreserved/thawed ovaries to the heterotopic sites. Thus, the promotion of blood supply is an effective strategy to inhibit/reduce the ischemic damage to ovarian follicles. Here, the angiogenic potential of alginate (Alg) + fibrin (Fib) hydrogel enriched with melatonin (Mel) and CD144⁺ endothelial cells (ECs) was assessed on encapsulated cryopreserved/thawed ovaries following transplantation to heterotopic sites in rats.

METHODS

Alg + Fib hydrogel was fabricated by combining 2% (w/v) sodium Alg, 1% (w/v) Fib, and 5 IU thrombin at a ratio of 4: 2: 1, respectively. The mixture was solidified using 1% CaCl₂. Using FTIR, SEM, swelling rate, and biodegradation assay, the physicochemical properties of Alg + Fib hydrogel were evaluated. The EC viability was examined using an MTT assay. Thirty-six adult female rats (aged between 6 and 8 weeks) with a normal estrus cycle were ovariectomized and enrolled in this study. Cryopreserved/thawed ovaries were encapsulated in Alg + Fib hydrogel containing 100 µM Mel + CD144⁺ ECs (2 × 10⁴ cells/ml) and transplanted into the subcutaneous region. Ovaries were removed after 14 days and the expression of Ang-1, and Ang-2 was monitored using real-time PCR assay. The number of vWF⁺ and α-SMA⁺ vessels was assessed using IHC staining. Using Masson's trichrome staining, fibrotic changes were evaluated.

RESULTS

FTIR data indicated successful interaction of Alg with Fib in the presence of ionic cross-linker (1% CaCl₂). Data confirmed higher biodegradation and swelling rates in Alg + Fib hydrogel compared to the Alg group (p < 0.05). Increased viability was achieved in encapsulated CD144⁺ ECs compared to the control group (p < 0.05). IF analysis showed the biodistribution of Dil⁺ ECs within hydrogel two weeks after transplantation. The ratio of Ang-2/Ang-1 was statistically up-regulated in the rats that received Alg + Fib + Mel hydrogel compared to the control-matched groups (p < 0.05). Based on the data, the addition of Mel and CD144⁺ ECs to Alg + Fib hydrogel reduced fibrotic changes. Along with these changes, the number of vWF⁺ and α-SMA⁺ vessels was increased in the presence of Mel and CD144⁺ ECs.

CONCLUSIONS

Co-administration of Alg + Fib with Mel and CD144⁺ ECs induced angiogenesis toward encapsulated cryopreserved/thawed ovarian transplants, resulting in reduced fibrotic changes.

Zinc and Respiratory Viral Infections: Important Trace Element in Anti-viral Response and Immune Regulation

Influenza viruses, respiratory syncytial virus (RSV), and SARS-COV2 are among the most dangerous respiratory viruses. Zinc is one of the essential micronutrients and is very important in the immune system. The aim of this narrative review is to review the most interesting findings about the importance of zinc in the anti-viral immune response in the respiratory tract and defense against influenza, RSV, and SARS-COV2 infections. The most interesting findings on the role of zinc in regulating immunity in the respiratory tract and the relationship between zinc and acute respiratory distress syndrome (ARDS) are reviewed, as well. Besides, current findings regarding the relationship between zinc and the effectiveness of respiratory viruses' vaccines are reviewed. The results of reviewed studies have shown that zinc and some zinc-dependent proteins are involved in anti-viral defense and immune regulation in the respiratory tract. It seems that zinc can reduce the viral titer following influenza infection. Zinc may reduce RSV burden in the lungs. Zinc can be effective in reducing the duration of viral pneumonia symptoms. Zinc may enhance the effectiveness of hydroxychloroquine in reducing mortality rate in COVID-19 patients. Besides, zinc has a positive effect in preventing ARDS and ventilator-induced lung damage. The relationship between zinc levels and the effectiveness of respiratory viruses' vaccines, especially influenza vaccines, is still unclear, and the findings are somewhat contradictory. In conclusion, zinc has anti-viral properties and is important in defending against respiratory viral infections and regulating the immune response in the respiratory tract.

Review of ovarian tissue cryopreservation techniques for fertility preservation

Ovarian failure and ovarian malfunction are among major fertility problems in women of reproductive age (18-35 years). It is known that various diseases, such as ovarian cancer and premature ovarian failure, besides certain treatments, such as radiotherapy and chemotherapy of other organs, can affect the normal process of folliculogenesis and cause infertility. In recent years, various procedures have been proposed for the treatment of infertility. One of the newest methods is the use of cryopreservation ovarian fragments after cancer treatment. According to some studies, this method yields very satisfactory results. Although ovarian tissue cryopreservation (OTC) is an accepted technique of fertility preservation, the relative efficacy of cryopreservation protocols remains controversial. Considering the controversies about these methods and their results, in this study, we aimed to compare different techniques of ovarian cryopreservation and investigate their advantages and disadvantages. Reviewing the published articles may be possible to identify appropriate strategies and improve infertility treatment in these patients.

[3 dimensional acetabulum roof-plasty in children, adolescents and adults, methodology and results]

The Salter innominate osteotomy is not indicated if there is a combination of hip dysplasia and hip deformity. The Chiari osteotomy seems to us not to be an adequate therapy not only because of a numerous disadvantages but also because it does not achieve a real enlargement or a congruent hip surface. We treat a hip deformity of children, youths and adults with a method we name three dimensional roof arthroplasty. This method realise a spheric enlarging of the roof and has achieved significant results. The method and results are presented.

[The patella following implantation of a knee prosthesis, with reference to patella plasty (author's transl)]

The follow-up patella using knee prosthesis depends on the followings: a) advancement of femoropatellar arthrosis, b) shape and kind of surface of the fossa patellaris femoris, c) kind of knee prosthesis. To treat the patella arthrosis patella plasty is a good alternative to a patella prosthesis. This has been noticed by good or very good results 34 Patients out of 43. It has no complications and does not prevent the use of patella prosthesis if necessary.

[Fixation of the osteotomised greater trochanter by total hip prosthesis in 181 cases. Advantages of the fixation with intramedullary Kirschner wire and the figure-of-eight wire loop (author's transl)]

It is mostly possible to implant a total hip prosthesis without an osteotomy of the greater trochanter. It is however necessary to do it in some cases such as an ankylosed hip, a reimplantation and a severe form of the coxarthrosis. 181 patients have been followed up. The fixation by intramedullary Kirschner wire and figure-of-eight wire loop has been of success. It is a simple method. No fracture of the greater trochanter has been observed.

[The importance of the combination of the special x-ray with the arthrography in congenital displacement of the hip (author's transl)]

Arthrography is an important method of diagnosis of congenital displacement of the hip. It reveals the interposition of the soft tissue and the correctness of the position of the femur after a reduction of the hip joint. Arthrography only in a anterior posterior position cannot always demonstrate the real relationship between the femur and the pelvis. An x-ray of the arthrography in 45 degrees oblique position (Foramen obturatorium position) can reveal the situation.

[Surgical treatment of chondromalacia patellae according to Maquet/Bandi--indication, technique, results (author's transl)]

Degenerative changes of the femoropatellar joint are being observed increasingly more often. These may be due to various disturbances of the gliding movement and gliding plane. The article describes the clinical and x-ray symptoms and the therapy; in most cases, additional surgery will be necessary besides antepositioning according to the technique described by Bandi.--Follow-up examinations of 32 patients showed that in 28 of 35 surgically treated knee joints, a positive influence had been exercised on the complaints, load capacity and walking distance.

[Alternatives for the operative treatment of the pseudarthrosis (author's transl)]

The stable osteosynthesis and bone grafting mostly cause the osseous healing of a false joint (pseudarthrosis). There are cases of pseudarthrosis in combination with other adverse failures. For them even an osseous healing would not achieve painlessness and usability of the limb, but the alternative operation might result in a satisfactory effect.

[Arthrodesis of the wrist with the use of bone graft and stable plate osteosynthesis. Results in 27 patients (author's transl)]

36 arthrodesis of the wrist have been controlled. The operative technique could be divided into two groups. On the first group a stable osteosynthesis and cortico-cancellous bone graft have been used. The second group has been treated by other internal rigid fixation. 13 patients of the first and 14 of the second group have been followed up. It was possible to obtain an arthrodesis by all methods. The stable kind of arthrodesis makes the handposition secure, the postoperative immobilization in cast much shorter and avoids the danger of pseudarthrosis.

[To discharge one compartment of the knee without a varisation or valgisation osteotomy in the knee region (author's transl)]

The correction of a varus or valgus deformity around the knee joint as prophylaxis or as a therapy of monocompartmental osteoarthritis of the knee is limited in its indication and of the amount of correction. The experiments have shown a possibility of discharging one compartment by a translocation of the knee to lateral or medial side after a supracondylar osteotomy. The method and its indication have been discussed.

[The effect of correction of the varus or valgus deformity of the knee (author's transl)]

The distribution of pressure force (load) on the tibia-plateau in a normal knee as well as varus or valgus deformity has been measured electronically and also studied by photoelastic experiments. The translocation of it by changing the knee axis has been demonstrated. The significance of the pressure force causing monocompartmental gonarthritis has been shown. The causal therapy is a correction of the valgus or varus deformity. The effect of this operation lies in the biomechanical discharge of the damaged compartment.

[Therapeutic hazard of supracondylar humeral fracture in a child]

A case of a supracondylar fracture in a 4-year-old female is presented. The risks of treatment are discussed. The question is raised whether the complication which resulted could have been avoided.

[Osteosynthese in scapula fractures (author's transl)]

Fractures of the scapula can be mostly conservativly. Dislocated fractures can be easily adjusted by suitable approaches. Rigid fixation allows early mobilisation, which is of very importance for the shoulderjoint. Some dislocated cases have been described and the problems of conservatively treated fractures have been discussed. Follow-up of some with stable fixation treated scapulafractures show that it is possible to gain a perfect functional result and a painless shoulderjoint in some hopeless cases.