Functional Regeneration Research Articles

Rebuilding the autoimmune-damaged corneal stroma through topical lubrication.

Corneal lubrication is the most common treatment for relieving the signs and symptoms of dry eye and is considered to be largely palliative with no regenerative functions. Here we challenge this notion by demonstrating that wetting the desiccated cornea of an aqueous-deficient mouse model with the simplest form of lubrication, a saline-based solution, is sufficient to rescue the severely disrupted collagen-rich architecture of the stroma, the largest corneal compartment that is essential to transparency and vision. At the single cell level we show that stromal keratocytes responsible for maintaining stromal integrity are converted from an inflammatory state into unique reparative cell states by lubrication alone, thus revealing the extensive plasticity of these cells and the regenerative function of lubricating the surface. We further show that the generation of a reparative phenotype is due, in part, to disruption of an IL1β autocrine amplification loop promoting chronic inflammation. Thus, our study uncovers the regenerative potential of topical lubrication in dry eye and represents a paradigm shift in our understanding of its therapeutic impact.

KDF1 promotes ameloblast differentiation by inhibiting the IKK/IκB/NF-κB axis.

Enamel protects teeth from external irritation and its formation involves sequential differentiation of ameloblasts, a dental epithelial cell. Keratinocyte differentiation factor 1 (KDF1) is important in the development of epithelial tissues and organs. However, the specific role of KDF1 in enamel formation and corresponding regulatory mechanisms are unclear. This study demonstrated that KDF1 was persistently expressed in all stages of ameloblast differentiation, through RNAscope in situ hybridization. KDF1 expression in the mouse ameloblast cell line LS8 was demonstrated via immunofluorescence assay. KDF1 was knocked out in LS8 cells using the CRISPR/Cas-9 system or overexpressed in LS8 cells through lentiviral infection. In vitro ameloblast differentiation induction, quantitative reverse transcription PCR, western blot analysis, and alkaline phosphatase (ALP) assay indicated that knockout or overexpression of KDF1 in LS8 cells decreased or increased the mRNA and protein levels of several key amelogenesis markers, as well as ALP activity. Furthermore, liquid chromatography-mass spectrometry and co-immunoprecipitation analyses revealed that KDF1 can interact with the IKK complex, thereby inhibiting the NF-κB pathway. Suppressing NF-κB activity partially recovered the decreased ameloblast differentiation in LS8 cells induced by KDF1-knockout. This study demonstrated that KDF1 can promote ameloblast differentiation of LS8 cells by inhibiting the IKK/IκB/NF-κB axis, and is a potential target for functional enamel regeneration.

Osteogenic tailoring of oriented bone matrix organization using on/off micropatterning for osteoblast adhesion on titanium surfaces.

Titanium (Ti) implants are well known for their mechanical reliability and chemical stability, crucial for successful bone regeneration. Various shape control and surface modification techniques to enhance biological activity have been developed. Despite the crucial importance of the collagen/apatite bone microstructure for mechanical function, antimicrobial properties, and biocompatibility, precise and versatile pattern control for regenerating the microstructure remains challenging. Here, we developed a novel osteogenic tailoring stripe-micropatterned MPC-Ti substrate that induces genetic-level control of oriented bone matrix organization. This biomaterial was created by micropatterning 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer onto a titanium (Ti) surface through a selective photoreaction. The stripe-micropatterned MPC-Ti substrate establishes a distinct interface for cell adhesion, robustly inducing osteoblast cytoskeleton alignment through actin cytoskeletal alignment, and facilitating the formation of a bone-mimicking-oriented collagen/apatite tissue. Moreover, our study revealed that this bone alignment process is promoted through the activation of the Wnt/β-catenin signaling pathway, which is triggered by nuclear deformation induced by strong cellular alignment guidance. This innovative material is essential for personalized next-generation medical devices, offering high customizability and active restoration of the bone microstructure. STATEMENT OF SIGNIFICANCE: This study demonstrates a novel osteogenic tailoring stripe-micropatterned MPC-Ti substrate that induces osteoblast alignment and bone matrix orientation based on genetic mechanism. By employing a light-reactive MPC polymer, we successfully micropatterned the titanium surface, creating a biomaterial that stimulates unidirectional osteoblast alignment and enhances the formation of natural bone-mimetic anisotropic microstructures. The innovative approach of regulating cell adhesion and cytoskeletal alignment activates the Wnt/β-catenin signaling pathway, crucial for both bone differentiation and orientation. This study presents the first biomaterial that artificially induces the construction of mechanically superior anisotropic bone tissue, and it is expected to promote functional bone regeneration by enhancing bone differentiation and orientation-targeting both the quantity and quality of bone tissue.

Bone regeneration in rabbit cranial defects: 3D printed polylactic acid scaffolds gradually enriched with marine bioderived calcium phosphate

ObjectiveThis study aimed to evaluate the in vivo biocompatibility, mechanical performance and osteoconductive potential of 3D-printed polylactic acid (PLA) scaffolds enriched with marine bioderived calcium phosphate (bioCaP) for bone tissue engineering. Materials and MethodsPLA-bioCaP composite scaffolds were specifically designed for the rabbit cranial defect model by 3D printing, with a uniform distribution of open square-shaped pores and contributions in bioCaP. Physicochemical and mechanical characterization and the evaluation of biological response are presented. ResultsThe scaffolds demonstrated mechanical properties comparable to human bones, integration with the host bone, and osteoconductive behavior promoting cell ingrowth from the defect edge. Strong mineralized tissue ingrowth through the scaffolds’ pores was observed, providing notable support to the host bone. In quantitative terms, micro-CT and histomorphometry analysis post-implantation revealed no significant differences in bone regeneration across all groups. ConclusionThe 3D-printed scaffolds with perpendicular patterning, open porosity, and proposed composition displayed satisfactory mechanical properties, biocompatibility, and osteoconductive response. The scaffolds promoted bone regeneration at similar levels as the PLA. The highest contribution of bioCaP promoted a positive influence in certain histomorphometric parameters; however, it did not significantly improve their osteogenic capability. Further research is required to optimize scaffold composition and enhance their osteogenic potential. Clinical RelevanceThis study presents a significant advancement in bone tissue engineering through the development of personalized composite scaffolds for bone-related applications. The clinical implications of this research are profound, especially considering the increasing demand for functional bone regeneration technologies capable of producing cost-effective producing cost-effective customized scaffolds.

Human liver progenitor-like cells-derived extracellular vesicles promote liver regeneration during acute liver failure

Hepatocyte-derived liver progenitor-like cells (HepLPCs) exhibit a remarkable capacity to support liver function by detoxifying ammonia, promoting native liver regeneration, and suppressing inflammation, which leads to improvements in the recovery and survival of animals with acute liver failure (ALF). However, the mechanism through which HepLPCs promote liver regeneration is unclear. Here, we isolated HepLPC-derived extracellular vesicles (HepLPC-EVs) from conditioned media and performed microRNA sequencing analysis. Our results showed HepLPC-EVs promoted liver regeneration in mice with carbon tetrachloride or acetaminophen induced ALF. Cell cycle progression and proliferation of primary human hepatocytes were promoted after coculture with HepLPC-EVs. Exosomal miRNA sequencing confirmed that HepLPC-EVs were enriched with miR-183-5p, which played an essential role in ameliorating ALF. Mechanistically, HepLPC-derived exosomal miR-183-5p negatively regulated the expression of the target gene FoxO1, activated the Akt/GSK3β/β-catenin signaling pathway, and thereby promoted liver regeneration and restoration of normal liver function. These results indicate that during ALF, HepLPC-Exos mediate liver regeneration mainly through a paracrine exosome-dependent mechanism and these effects accelerate liver regeneration and lead to the restoration of normal liver function.Graphical

The roles of regulatory-compliant media and inflammatory/oxytocin priming selection in enhancing human mesenchymal stem/stromal cell immunomodulatory properties

Osteoarthritis (OA) represents a significant global health burden without a known disease modifying agent thereby necessitating pursuit of innovative therapeutic approaches. The infrapatellar fat pad (IFP) serves as a reservoir of mesenchymal stem/stromal cells (MSC), and with adjacent synovium plays key roles in joint disease affecting local inflammatory responses. Therapeutically, IFP-MSC have garnered attention for their potential in OA treatment due to their immunomodulatory and regenerative properties. However, optimizing their therapeutic efficacy necessitates a comprehensive understanding of how growth medium and inflammatory/hormonal priming influence their behavior. In this study, we isolated and expanded IFP-MSC in three different growth media: DMEM + 10% fetal bovine serum (FBS), DMEM + 10% human platelet lysate (HPL), and xeno-/serum-free synthetic (XFSF) medium. Subsequently, cells were induced with an inflammatory/fibrotic cocktail (TIC) with or without oxytocin (OXT). We evaluated various parameters including growth kinetics, phenotype, immunomodulatory capacity, gene expression, and macrophage polarization capacity. Our results revealed significant differences in the behavior of MSC cultured in different media. IFP-MSC cultured in HPL and XFSF exhibited superior growth kinetics and colony-forming abilities compared to those cultured in FBS. Furthermore, both HPL and XFSF media enhanced the expression of MSC markers (> 90%) and potentiated their immunomodulatory properties. Notably, XFSF-conditioned IFP-MSC demonstrated the highest attenuation of peripheral blood mononuclear cell (PBMC) proliferation, indicating their robust immunosuppressive capacity. Additionally, TIC priming further augmented the immunomodulatory functionality of MSC, with IFP-MSC exhibiting enhanced suppression of PBMC proliferation upon TIC priming. Of particular interest, gene expression analysis revealed distinct patterns in TIC + OXT induced MSC compared to TIC only induced, with upregulation of genes associated with immunomodulatory and regenerative functions. Furthermore, TIC + OXT priming promoted M2 polarization in macrophages, suggesting a potential therapeutic strategy for immune-mediated inflammatory joint conditions including OA. Our findings highlight the critical influence of growth medium and inflammatory/hormonal priming on MSC behavior and therapeutic potential. XFSF and HPL media offer promising alternatives to FBS, enhancing MSC growth and immunomodulatory properties. Moreover, TIC + OXT priming represents a novel approach to augment MSC immunomodulation and promote M2 polarization, providing insights into potential therapeutic strategies for OA and other immune-mediated inflammatory conditions.

Potential of Stem-Cell-Induced Peripheral Nerve Regeneration: From Animal Models to Clinical Trials

Peripheral nerve injury has become an increasingly prevalent clinical concern, causing great morbidity in the community. Although there have been significant advancements in the treatment of peripheral nerve damage in recent years, the issue of long-term nerve regeneration remains. Furthermore, Wallerian degeneration has created an obstacle to long-term nerve regeneration. For this reason, there has been extensive research on the use of exogenous and endogenous stem cells as an adjunct or even primary treatment option for peripheral nerve injury. The plasticity and inducibility of stem cells make them an enticing option for initiating neuronal cell regrowth and optimal sensory and functional nerve regeneration. Peripheral nerve injury has a broad range of causative factors and etiologies. As such, unique stem cell-induced peripheral nerve treatments are being investigated to ameliorate the damage incited by all causes, including trauma, neuropathy, and systemic neurodegenerative diseases. This review is oriented to outline the potential role of stem cell therapies in peripheral nerve injury versus the current standards of care, compare the benefits and drawbacks of specific stem cell lines under investigation, and highlight the current models of stem cell therapy in the peripheral nervous system, with the ultimate goal of narrowing down and optimizing the role and scope of stem cell therapy in peripheral nerve injury.

Direct reprogramming of fibroblasts into spiral ganglion neurons by defined transcription factors

AbstractDegeneration of the cochlear spiral ganglion neurons (SGNs) is one of the major causes of sensorineural hearing loss and significantly impacts the outcomes of cochlear implantation. Functional regeneration of SGNs holds great promise for treating sensorineural hearing loss. In this study, we systematically screened 33 transcriptional regulators implicated in neuronal and SGN fate. Using gene expression array and principal component analyses, we identified a sequential combination of Ascl1, Pou4f1 and Myt1l (APM) in promoting functional reprogramming of SGNs. The neurons induced by APM expressed mature neuronal and SGN lineage‐specific markers, displayed mature SGN‐like electrophysiological characteristics and exhibited single‐cell transcriptomes resembling the endogenous SGNs. Thus, transcription factors APM may serve as novel candidates for direct reprogramming of SGNs and hearing recovery due to SGN damages.

Application and progress of bio-derived materials in bladder regeneration and repair

To summarize the research progress of bio-derived materials used for bladder regeneration and repair. The recent domestic and foreign sutudies on bio-derived materials used for bladder regeneration and repair, including classification, morphology optimization process, tissue regeneration strategies, and relevant clinical trials, were summarized and analyzed. Numerous types of bio-derived materials are employed in bladder regeneration and repair, characterized by their low immunogenicity and high inducible activity. Surface modification, gelation, and other morphology optimization process have significantly broadened the application scope of bio-derived materials. These advancements have effectively addressed complications, such as perforation and urolith formation, that may arise during bladder regeneration and repair. The strategy of tissue regeneration utilizing bio-derived materials, targeting the regeneration of bladder epithelium, smooth muscle, blood vessels, and nerves, offers a novel approach to achieving functional regeneration of bladder. Bio-derived materials show great promise for use in bladder regeneration and repair, yet the results from clinical trials with these materials have been less than satisfactory. Bio-derived materials are widely used in bladder regeneration and repair due to the good biocompatibility, low immunogenicity, and degradable properties, yet face a series of problems, and there are no commercialized bladder tissue engineering grafts used in clinical treatment.

A single-cell transcriptomic atlas of human stem cells from apical papilla during the committed differentiation.

Human stem cells derived from the apical papilla (SCAPs) are recognized for their multilineage differentiation potential and their capacity for functional tooth root regeneration. However, the molecular mechanisms underlying odonto/osteogenic differentiation remain largely unexplored. In this study, we utilized single-cell RNA sequencing (scRNA-seq) to conduct an in-depth analysis of the transcriptional changes associated with chemically induced osteogenesis in SCAPs. scRNA-seq identified SCAPs as distinct subpopulations. Differentially expressed genes (DEGs) and Gene Ontology (GO) analyses were conducted to evaluate the potential function of each cluster. Pseudotime trajectory analysis was employed to elucidate the potential differentiation processes of the identified SCAP populations. To investigate the osteo/odontogenic potential of Deiodinase Iodothyronine Type 2 (DIO2) on SCAPs, we performed alkaline phosphatase staining, western blot analysis, Alizarin Red S staining and immunofluorescence staining. Additionally, SCAP components were transplanted into mouse calvarial defects to evaluate osteogenesis invivo. The analysis of cell clusters derived from our scRNA-seq data revealed a significant shift in cellular composition when cells were cultured in a mineralization induction medium compared to those cultured in a complete medium. Both groups exhibited heterogeneity, with some cells intrinsically predisposed to osteogenesis and others appearing to be primed for proliferative functions. Notably, we identified a subpopulation characterized by high expression of DIO2, which exhibited pronounced osteogenic activity during differentiation. Our study is the first to reveal a shift in the cellular composition of SCAPs when cultured in a mineralization induction medium compared to a complete medium. Following both invitro and invivo validation, the DIO2+ subpopulation exhibited the highest transcriptional similarity to osteogenic function, suggesting its potential utility in tissue regeneration applications.

Harnessing the regenerative potential of interleukin11 to enhance heart repair

Balancing between regenerative processes and fibrosis is crucial for heart repair, yet strategies regulating this balance remain a barrier to developing therapies. The role of Interleukin 11 (IL11) in heart regeneration remains controversial, as both regenerative and fibrotic functions have been reported. We uncovered that il11a, an Il11 homolog in zebrafish, can trigger robust regenerative programs in zebrafish hearts, including cardiomyocytes proliferation and coronary expansion, even in the absence of injury. Notably, il11a induction in uninjured hearts also activates the quiescent epicardium to produce epicardial progenitor cells, which later differentiate into cardiac fibroblasts. Consequently, prolonged il11a induction indirectly leads to persistent fibroblast emergence, resulting in cardiac fibrosis. While deciphering the regenerative and fibrotic effects of il11a, we found that il11-dependent fibrosis, but not regeneration, is mediated through ERK activity, suggesting to potentially uncouple il11a dual effects on regeneration and fibrosis. To harness the il11a’s regenerative ability, we devised a combinatorial treatment through il11a induction with ERK inhibition. This approach enhances cardiomyocyte proliferation with mitigated fibrosis, achieving a balance between regenerative processes and fibrosis. Thus, we unveil the mechanistic insights into regenerative il11 roles, offering therapeutic avenues to foster cardiac repair without exacerbating fibrosis.

Epineural Scarring Visualization and Noninvasive Quantification of a Severe Posttraumatic Complication: An Experimental Magnetic Resonance Neurography Study.

Peripheral nerve scarring is a severe yet common complication following nerve injury or surgery that can lead to impaired nerve function, including chronic pain and sensory or motor deficits. In this study, we aimed to establish high-resolution magnetic resonance neurography (MRN) to accurately visualize and monitor de novo-formed epineural fibrotic adhesions (EFAs) of the sciatic nerve in a rat nerve injury model. Employing an established model to induce overshooting EFA, the study included 3 experimental groups of animals (n = 6 each): a positive control group (PC), an intervention group (IG), and a sham group. All groups underwent surgical nerve exposure: both PC and IG received an application of 10 μL 2.5% glutaraldehyde to induce EFA, but only IG received an additional preventive wrapping of the nerve with a collagen-containing matrix. Magnetic resonance imaging was performed 6, 8, and 12 weeks postoperatively using a standardized protocol including T2w and T1w without and with contrast media. Motor function and nerve regeneration was assessed using the visual static sciatic index. Histological specimens were obtained 12 weeks postoperatively and correlated with imaging. On high-resolution MRN, prominently contrast-enhancing epineural sleeves were present in vivo, which corresponded to histologically confirmed EFA (ratio of EFA to nerve area MRN 1.512 ± 0.106 vs histological ratio 1.459 ± 0.208, nonsignificant). As expected, average EFA in IG (0.310 ± 0.118 mm2) was smaller than in PC (0.909 ± 0.212 mm2, P < 0.01). Also, the average EFA in sham (0.386 ± 0.030 mm2) was less pronounced than in PC (P < 0.01). There was no significant difference in the average EFA between IG und sham. The EFA correlated with the functional outcome, which was measured by visual static sciatic index (correlation coefficient -0.59, P < 0.05). The results of the present study for the first time confirm the clinical observation that epineural thickening on contrast-enhanced T1w imaging following manipulation to a nerve indeed corresponds to overshooting epineural scarring, which may be linked to impaired nerve function. This can be followed noninvasively in vivo over time providing an important basis for clinical decision-making in cases where further invasive therapies may be necessary.

Life-long functional regeneration of in vivo airway epithelium by the engraftment of airway basal stem cells.

Durable and functional regeneration of the airway epithelium in vivo with transplanted stem cells has the potential to reconstitute healthy tissue in diseased airways, such as in cystic fibrosis or primary ciliary dyskinesia. Here, we present detailed protocols for the preparation and culture expansion of murine primary and induced pluripotent stem cell-derived airway basal stem cells (iBCs) and methods for their intra-airway transplantation into polidocanol-conditioned murine recipients to achieve durable in vivo airway regeneration. Reconstitution of the airway tissue resident epithelial stem cell compartment of immunocompetent mice with syngeneic donor cells leverages the extensive self-renewal and multipotent differentiation properties of basal stem cells (BCs) to durably generate a broad diversity of mature airway epithelial lineages in vivo. Engrafted donor-derived cells re-establish planar cell polarity as well as functional ciliary transport. By using this same approach, human primary BCs or iBCs transplanted into NOD-SCID gamma recipient mice similarly display engraftment and multilineage airway epithelial differentiation in vivo. The time to generate mouse or human iBCs takes ~60 d, which can be reduced to ~20 d if previously differentiated cells are thawed from cryopreserved iBC archives. The tracheal conditioning regimen and cell transplantation procedure is completed in 1 d. A competent graduate student or postdoctoral trainee should be able to perform the procedures listed in this protocol.

Pressure Ulcers and Nutrients: From Established Evidence to Gaps in Knowledge.

Pressure ulcers (PUs) are caused by continuous pressure or friction on the skin that damages tissue, especially over bony prominences. A critical factor in the development and progression of PUs is poor nutritional status, which often involves deficiencies in essential nutrients such as proteins, vitamins (A, C, D, E, K, and the B complex), and trace elements (including zinc, selenium, copper, iron, and manganese). These micronutrients are vital for effective wound healing, as they play significant roles in cellular repair, immune function, and tissue regeneration. Laboratory tests for serum albumin, prealbumin, transferrin, retinol-binding protein, and anthropometric measures like height, weight, and body mass index (BMI) are used to evaluate a patient's nutritional status. Screening tools such as the Mini Nutritional Assessment (MNA), Malnutrition Universal Screening Tool (MUST), LPZ questionnaire, and Subjective Global Assessment (SGA) are commonly employed. Emerging evidence from various studies, including in vitro, in vivo, and clinical trials, underscores the importance of personalized nutritional interventions in managing PUs. Unlike generic dietary plans, tailored nutrition that addresses the specific needs of individuals shows greater potential in promoting wound healing and improving clinical outcomes. This synthesis of existing research highlights the critical influence of micronutrients on the healing process of PUs. It suggests that a personalized approach to nutrition, which takes into account individual patient requirements and deficiencies, is likely to be more effective than a one-size-fits- all strategy in the management of these complex wounds.

Controlled release of hydrogel-encapsulated mesenchymal stem cells-conditioned medium promotes functional liver regeneration after hepatectomy in metabolic dysfunction-associated steatotic liver disease

BackgroundGlobally, prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing, and there is an urgent need to develop innovative therapies that promote liver regeneration following hepatectomy for this disease. Surgical excision is a key therapeutic approach with curative potential for liver tumors. However, hepatic steatosis can lead to delayed liver regeneration and higher post-operative complication risk. Mesenchymal stem cells-conditioned medium (MSC-CM) is considered a rich source of paracrine factors that can repair tissues and restore function of damaged organs. Meanwhile, hydrogels have been widely recognized to load MSC secretome and achieve sustained release. This study aimed to evaluate the therapeutic effect of hydrogel-encapsulated MSC-CM on liver regeneration following partial hepatectomy (PHx) in a rodent model of diet-induced hepatic steatosis.MethodsMale Lewis rats were fed with a methionine and choline–deficient diet. After 3 weeks of feeding, PHx was performed and rats were randomly allocated into two groups that received hydrogel-encapsulated MSC-CM or vehicle via the intra-mesenteric space of the superior mesenteric vein (SMV).ResultsThe regeneration of the remnant liver at 30 and 168 h after PHx was significantly accelerated, and the expressions of proliferating cell nuclear antigen were significantly enhanced in the MSC-CM group. MSC-CM treatment significantly increased hepatic ATP and β-hydroxybutyrate content at 168 h after PHx, indicating that MSC-CM fosters regeneration not only in volume but also in functionality. The number of each TUNEL- and cleaved caspase-3 positive nuclei in hepatocytes at 9 h after PHx were significantly decreased in the MSC-CM group, suggesting that MSC-CM suppressed apoptosis. MSC-CM increased serum immunoregulatory cytokine interleukin-10 and interleukin-13 at 30 h after PHx. Additionally, mitotic figures and cyclin D1 expression decreased and hepatocyte size increased in the MSC-CM group, implying that this mode of regeneration was mainly through cell hypertrophy rather than cell division.ConclusionsMSC-CM represents a novel therapeutic approach for patients with MASLD requiring PHx.

Neurotrophic and synaptic effects of GnRH and/or GH upon motor function after spinal cord injury in rats

Thoracic spinal cord injury (SCI) profoundly impairs motor and sensory functions, significantly reducing life quality without currently available effective treatments for neuroprotection or full functional regeneration. This study investigated the neurotrophic and synaptic recovery potential of gonadotropin-releasing hormone (GnRH) and growth hormone (GH) treatments in ovariectomized rats subjected to thoracic SCI. Employing a multidisciplinary approach, we evaluated the effects of these hormones upon gene expression of classical neurotrophins (NGF, BDNF, and NT3) as well as indicative markers of synaptic function (Nlgn1, Nxn1, SNAP25, SYP, and syntaxin-1), together with morphological assessments of myelin sheath integrity (Klüver-Barrera staining and MBP immunoreactivity) and synaptogenic proteins (PSD95, SYP) by immunohystochemistry (IHC) , and also on the neuromotor functional recovery of hindlimbs in the lesioned animals. Results demonstrated that chronic administration of GnRH and GH induced notable upregulation in the expression of several neurotrophic and synaptogenic activity genes. Additionally, the treatment showed a significant impact on the restoration of functional synaptic markers and myelin integrity. Intriguingly, while individual GnRH application induced certain recovery benefits, the combined treatment with GH appeared to inhibit neuromotor recovery, suggesting a complex interplay in hormonal regulation post-SCI. GnRH and GH are bioactive and participate in modulating neurotrophic responses and synaptic restoration under neural damage conditions, offering insights into novel therapeutic approaches for SCI. However, the intricate effects of combined hormonal treatment accentuate the necessity for further investigation that conduce to optimal and novel therapeutic strategies for patients with spinal cord lesions.

LCZ696 (sacubitril/valsartan) alleviates residual cardiac remodeling of large ventricular aneurysms after surgical ventricular reconstruction by mediating circMap4k2/LIN28A/PDK1 pathway

Abstract Introduction The treatment of refractory heart failure (HF) with large ventricular aneurysms (LVA) faces difficulties and requires effective therapy. Surgical ventricular reconstruction (SVR) is used to reverse cardiac remodeling for these patients, however, residual remodeling and dysfunction after SVR limits the improvement of HF. Recently, we reported that circMap4k2 promoted cardiac regeneration in the plication zone and attenuated residual remodeling after SVR. LCZ696 (sacubitril/valsartan) can reduce cardiac remodeling in early HF, while efficacy is poor in refractory HF with severe remodeling. It is unclear whether LCZ696 could improve residual remodeling and regulate circMap4k2 after SVR attenuates partial cardiac remodeling. Purpose We aimed to explore whether LCZ696 would reverse residual remodeling after SVR and related mechanisms. Methods Adult Male C57BL/6 mice were subjected to myocardial infarction (MI) or sham surgery. Four weeks later, MI mice with a LVA underwent SVR or a second open-chest operation and were randomized to LCZ696 or vehicle for four-week. Echocardiography and histological analysis were used to evaluate heart function, cardiac remodeling, and myocardial regeneration. Bioinformatics analysis, molecular docking analysis, RNA immunoprecipitation (RIP) and RNA pulldown were used to explore the underlying mechanisms. Results Compared with vehicle-treated SVR and LCZ696-treated non-SVR mice, LCZ696-treated SVR mice had significantly smaller left ventricular volume, better ejection fraction, lower heart-to-body weight ratio, less myocardial fibrosis and more positive staining of Ki-67, phospho-histone H3, and Aurora B in the plication zone. LCZ696 up-regulated the cardiac expression of circMap4k2 in SVR mice. Silencing of circMap4k2 markedly blocked the curative effects of LCZ696 on SVR mice, while overexpression of circMap4k2 enhanced these effects. We predicted 22 proteins that may bind to circMap4k2, among which lin-28 homolog A (LIN28A) had the highest binding potential, and confirmed the combination between circMap4k2 and LIN28A. Mechanistically, LCZ696-induced circMap4k2 bound to LIN28A, increased downstream pyruvate dehydrogenase kinase 1 (PDK1) expression, which activated glycolysis in injured myocardium and ultimately promoted cardiomyocyte proliferation. Conclusions LCZ696 improves cardiac metabolism and increases cardiac regeneration in the plication zone by mediating circMap4k2/LIN28A/PDK1 pathway, thereby attenuating residual remodeling and restoring heart function after SVR.

Gene Therapy for Inflammatory Cascade in Intrauterine Injury with Engineered Extracellular Vesicles Hybrid Snail Mucus-enhanced Adhesive Hydrogels.

Early hyper-inflammation caused by intrauterine injury triggered subsequent intrauterine adhesion (IUA). STAT1-mediated M1 macrophages are confirmed to secrete pro-inflammatory cytokines to accelerate inflammatory cascade and IUA formation by multi-omics analysis and experimental verification. However, clinically used hyaluronic acid (HA) hydrogels are prone to slip out of injury sites due to poor bio-adhesion properties. Therefore, there are still challenges in applying hydrogels for M1 macrophage intervention in IUA treatment. Herein, an engineered extracellular vesicles (EVs) hybrid snail mucus (SM)-enhanced adhesive hydrogels to improve bio-adhesion property is fabricated and M1 macrophage intervention through targeting delivery and STAT1 silencing is achieved. First, inspired by the high bio-adhesion capacity of SM, SM and gelatin methacrylate (GelMA) solution are mixed to construct GelMA/SM (GS) hydrogel. Then, folic acid-modified extracellular vesicles (FA-EVs) are synthesized for targeting the delivery of STAT1-siRNA. Upon injection of FA-EVs hybrid GS hydrogel into the uterine cavity, a protective hydrogel layer forms on the surface of injury sites and sustains the release of STAT1-siRNA-loaded FA-EVs to curtail M1 macrophages generation through inhibiting STAT1 phosphorylation, resulting in reduction of myofibroblasts activation and collagen deposition. In addition, the pregnancy rate and the number of fetuses in rats treated with this hydrogel were much higher than those in other groups, suggesting that the hydrogel could promote functional endometrial regeneration and restore fertility. Overall, this study presents a promising strategy for employing FA-EVs hybrid adhesive hydrogel with superior bio-adhesion properties and M1 macrophage targeting delivery for IUA treatment and uterus recovery.

Programmable Artificial Skins Accomplish Antiscar Healing with Multiple Appendage Regeneration.

Functional appendage regeneration is essential for skin rehabilitation, but it has always failed by current existing healing approaches, owing to their inefficacy in preventing disfiguring scars. In this study, a novel regeneration-directing artificial skin (RDAS) system is presented, which is based on the rational design of multi-layered hydrogels that closely mimic natural skin matrices. By leveraging the programmability and architectural rigidity of DNA components, without the need for exogenous cell transplantation, such RDAS effectively minimizes tissue fibrosis by accurately guiding the regenerative process in wound fibroblasts, enabling rapid scarless wound repair, restoration of dermal function, and successful in situ regeneration of multiple appendages, such as hair follicles (HFs), sebaceous glands (SGs), and sweat glands (SwGs). Therefore, the RDAS offers a cell-free antiscarring therapeutic strategy for regenerative wound healing, resulting in improved outcomes. This innovative approach holds great potential for future clinical applications and burn rehabilitation.

Oriented artificial nanofibers and laser induced periodic surface structures as substrates for Schwann cells alignment.

People with injuries to the peripheral nervous system suffer from paralysis of the facial muscles, fingers and hands or toes and feet, often for the rest of their lives, due to its poor functional regeneration. Therefore, to improve patients' quality of life, there is an urgent need for conduits that effectively support the healing of large defects in nerve pathways through specific guidance of nerve cells. This paper describes two specific methods for achieving directed growth of Schwann cells, a type of glial cells that can support the regeneration of the nerve pathway by guiding the neuronal axons in the direction of their alignment. One method uses aligned polyamide-6 (PA-6) nanofibers produced via electrospinning on a very fast rotating structured collector, which enables easy nanofiber detachment, without additional effort. The other method implies the exposure of a poly(ethylene terephthalate) (PET) foil to a KrF* laser beam, that renders a nanorippled surface topography. Schwann cell growth on these substrates was inspected after one week of cultivation by means of scanning electron microscopy (SEM). For both methods we show that Schwann cells grow in a certain direction, predetermined by nanofiber and nanoripple orientation. In contrast, cells cultivated on randomly oriented nanofibers or unstructured surfaces, show an omnidirectional growth behavior. These two methods can be used to produce nerve conduits for the treatment of injuries to the peripheral nervous system.