Transplantation of Human Amniotic Mesenchymal Stem Cells Up-Regulates Angiogenic Factor Expression to Attenuate Diabetic Kidney Disease in Rats

BACKGROUND AND AIMS

Diabetic kidney disease (DKD) is a prevalent and intractable microvascular complication of diabetes mellitus (DM), the process of which is closely related to abnormal expression of angiogenesis-regulating factors (ARFs). Stem cell transplantation might be a novel strategy for treating DKD. This study aims to explore the effect of transplantation of human amniotic mesenchymal stem cells (hAMSCs) on renal microangiopathy in a type 1 DKD rat model (T1DRM).

METHODS

Seventy-two rats were randomly divided into three groups, including normal control group, DKD group, and hAMSCs transplantation group. T1DRM was established using a rat tail vein injection of streptozotocin (STZ) (55 mg/kg). hAMSCs were obtained from placental amniotic membranes during cesarean delivery and transplanted at 3 and 4 weeks through penile veins. At 6, 8, and 12 weeks following transplantation, blood glucose levels, renal function, pathological kidney alterations, and the expressions of ARFs' mRNA and protein were analyzed.

RESULTS

In T1DRM, transplanted hAMSCs that were homed at the injured site of kidneys increased ARFs' expression and decreased blood glucose levels. Compared to the DKD group, the levels of 24-h urinary protein, serum creatinine, urea, and kidney injury molecule-1 (KIM-1) were reduced in hAMSCs transplantation group. In terms of renal pathology such as the degree of basement membrane thickening, hAMSCs transplantation was also less severe than the DKD group, thereby alleviating kidney injury.

CONCLUSION

hAMSCs transplantation might ameliorate STZ-induced chronic kidney injury through increasing ARFs' expression in kidneys and lowering blood glucose levels.

Blind nasoenteric tube placement risks: A case report of misplacement into the pleural cavity

RATIONALE

Enteral nutrition is a critical component of care for critically ill patients. However, the blind insertion of a nasoenteric tube, despite being a simple procedure, carries inherent risks that necessitate a reevaluation of the technique.

PATIENT CONCERNS

A case of a 60-year-old female experienced the rare yet critical complication of a misplaced nasoenteric tube entering the thoracic cavity during a blind insertion procedure for enteral nutrition following a liver transplant.

DIAGNOSIS

Following liver transplantation, the patient was diagnosed with severe pneumonia, a right-sided hydropneumothorax, and severe malnutrition.

INTERVENTIONS

After the misplacement of the nasoenteric tube into the pleural cavity was detected from the chest X-ray, the tube was immediately removed, and the pneumothorax was actively managed. Subsequently, with the support of contrast radiography, the nasoenteric tube was successfully reinserted to provide the patient with nutritional support and promote rehabilitation.

OUTCOMES

The patient responded well to the intervention and was discharged in stable condition following complete recovery.

LESSONS

The case prompts a reevaluation of blind placement techniques and calls for the adoption of more reliable technologies to prevent similar incidents and ensure patient safety, such as electromagnetic and visualized guided placement technique.

Functional gradient characteristics analysis of preschool-aged children with autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by social and behavioral impairments, emerging in early childhood with unclear causes. The primary aim of this study is to investigate shifts in the functional gradients underlying hierarchical brain network organization in ASD and to assess their potential contribution to clinical symptom severity. Resting-state functional magnetic resonance imaging was used to examine changes in functional gradients across seven major brain networks in a cohort of 52 individuals with ASD and 40 healthy controls. In the somatomotor network, neither the first nor third gradient showed significant group differences; however, two regions-right paracentral lobule and right postcentral gyrus-exhibited significant differences in the second gradient. In the frontoparietal network, only the left middle frontal gyrus in the second gradient showed a significant group difference. For the ventral attention network, only the primary gradient exhibited significant differences in the left insula, the right insula, and the right median cingulate and paracingulate gyri. In the default mode network, all three gradients showed statistically significant differences. These results suggest potential neuroimaging biomarkers for assessing the severity of ASD in preschool-aged children.

Research progress on the regulatory mechanism of integrin-mediated mechanical stress in cells involved in bone metabolism

Mechanical stress is an internal force between various parts of an object that resists external factors and effects that cause an object to deform, and mechanical stress is essential for various tissues that are constantly subjected to mechanical loads to function normally. Integrins are a class of transmembrane heterodimeric glycoprotein receptors that are important target proteins for the action of mechanical stress stimuli on cells and can convert extracellular physical and mechanical signals into intracellular bioelectrical signals, thereby regulating osteogenesis and osteolysis. Integrins play a bidirectional regulatory role in bone metabolism. In this paper, relevant literature published in recent years is reviewed and summarized. The characteristics of integrins and mechanical stress are introduced, as well as the mechanisms underlying responses of integrin to mechanical stress stimulation. The paper focuses on integrin-mediated mechanical stress in different cells involved in bone metabolism and its associated signalling mechanisms. The purpose of this review is to provide a theoretical basis for the application of integrin-mediated mechanical stress to the field of bone tissue repair and regeneration.

An Osteoimmunomodulatory Biopatch Potentiates Stem Cell Therapies for Bone Regeneration by Simultaneously Regulating IL-17/Ferroptosis Signaling Pathways

Currently, there are still great challenges in promoting bone defect healing, a common health problem affecting millions of people. Herein an osteoimmunity-regulating biopatch capable of promoting stem cell-based therapies for bone regeneration is developed. A totally biodegradable conjugate is first synthesized, which can self-assemble into bioactive nano micelles (PPT NMs). This nanotherapy effectively improves the osteogenesis of periodontal ligament stem cells (PDLSCs) under pathological conditions, by simultaneously regulating IL-17 signaling and ferroptosis pathways. Incorporation of PPT NMs into biodegradable electrospun nanofibers affords a bioactive patch, which notably improves bone formation in two rat bone defect models. A Janus bio patch is then engineered by integrating the bioactive patch with a stem cell sheet of PDLSCs. The obtained biopatch shows additionally potentiated bone regeneration capacity, by synergistically regulating osteoimmune microenvironment and facilitating stem cell differentiation. Further surface functionalization of the biopatch with tannic acid considerably increases its adhesion to the bone defect, prolongs local retention, and sustains bioactivities, thereby offering much better repair effects in rats with mandibular or cranial bone defects. Moreover, the engineered bioactive patches display good safety. Besides bone defects, this osteoimmunity-regulating biopatch strategy can be applied to promote stem cell therapies for spinal cord injury, wound healing, and skin burns.

[Prospective study on the influence of dobutamine on blood perfusion in free flap repair of diabetic foot wounds]

Objective: To investigate the influence of clinical administration of dobutamine on blood perfusion in free flap repair of diabetic foot wounds. Methods: A prospective self-controlled study was conducted. From January to November 2022, 20 patients with diabetic foot who met the inclusion criteria were hospitalized in the Department of Burns and Plastic Surgery of Affiliated Hospital of Zunyi Medical University, including 9 males and 11 females, aged from 44 to 75 years, with the foot wounds area ranging from 5 cm×4 cm to 20 cm×10 cm, which were repaired by free anterolateral thigh flaps. Heart rate (HR) and mean arterial pressure (MAP) were recorded before anesthesia induction, 10 minutes after vascular recanalization, when the target blood pressure (i.e., MAP being 6-10 mmHg (1 mmHg=0.133 kPa) higher than that before anesthesia induction) was reached after infusion of dobutamine, and 10 minutes after tracheal catheter removal. Additionally, indocyanine green, a contrast agent, was injected intravenously at 10 minutes after vascular recanalization and when the target blood pressure was reached after infusion of dobutamine to assess flap blood perfusion using infrared imager, and the area ratio of flaps with hyperperfusion and hypoperfusion was calculated. Other recorded variables included flap harvesting area, surgical duration, total fluid infusion amount, infusion dose and total usage of dobutamine, intraoperative adverse events, postoperative flap complications, and follow-up outcomes. Data were statistically analyzed with paired sample t test, analysis of variance for repeated measurement, Bonferroni method, and generalized estimating equation. Results: Compared with those before anesthesia induction, HR and MAP of patients were significantly decreased at 10 minutes after vascular recanalization (P<0.05), while HR and MAP of patients were significantly increased when the target blood pressure was reached after infusion of dobutamine (P<0.05). Compared with those at 10 minutes after vascular recanalization, HR and MAP of patients were significantly increased when the target blood pressure was reached after infusion of dobutamine and at 10 minutes after tracheal catheter removal (P<0.05). Compared with those when the target blood pressure was reached after infusion of dobutamine, HR and MAP of patients were significantly decreased at 10 minutes after tracheal catheter removal (P<0.05). The area ratio of flaps with hyperperfusion of patients was 0.63±0.11 when the target blood pressure was reached after infusion of dobutamine, which was significantly higher than 0.31±0.09 at 10 minutes after vascular recanalization (t=-9.92, P<0.05). The area ratio of flaps with hypoperfusion of patients was 0.12±0.05 when the target blood pressure was reached after infusion of dobutamine, which was significantly lower than 0.45±0.10 at 10 minutes after vascular recanalization (t=17.05, P<0.05). The flap harvesting area of patients was (174±35) cm², the surgical duration was (372±52) min, the total fluid infusion amount was (2 485±361) mL, the infusion dose of dobutamine was 3-13 μg·kg⁻¹·min⁻¹, and the total usage of dobutamine was 5.7 (2.1, 9.7) mg. Two patients showed a significant increase in MAP during the infusion of dobutamine compared with that at 10 minutes after vascular recanalization, but before reaching 6 mmHg higher than that before anesthesia induction, their HR had reached the maximum (over 130 beats/min). The HR gradually returned to around 90 beats/min after the infusion of dobutamine was stopped. On post operation day 2, one patient had partial necrosis at the distal part of the flap, which was repaired by transplantation of thin split-thickness skin graft from the opposite thigh. During the follow-up of 3 to 6 months after operation, all the flaps survived well, with soft texture and well-formed shape, and no adverse cardiovascular events of patients were reported. Conclusions: The administration of dobutamine in free flap repair of diabetic foot wounds can significantly improve the MAP of patients, expand the area of hyperperfusion, reduce the area of hypoperfusion, and enhance the flap viability, with promising short-term follow-up results, which is suitable for promotion in clinical applications.

Metformin enhances the therapeutic effects of extracellular vesicles derived from human periodontal ligament stem cells on periodontitis

Metformin has shown outstanding anti-inflammatory and osteogenic abilities. Mesenchymal stem cell-derived extracellular vesicles (EVs) reveal promising therapeutic potency by carrying various biomolecules. This study explored the effects of metformin on the therapeutic potential of EVs derived from human periodontal ligament stem cells (PDLSCs) for periodontitis. PDLSCs were cultured in osteogenic medium with or without metformin, and the supernatant was then collected separately to extract EVs and metformin-treated EVs (M-EVs). After identifying the characteristics, we evaluated the anti-inflammatory and osteogenic effects of EVs and M-EVs in vivo and in vitro. Osteogenic differentiation of PDLSCs was markedly enhanced after metformin treatment, and the effect was dramatically inhibited by GW4896, an inhibitor of EVs' secretion. Metformin significantly increased EVs' yields and improved their effects on cell proliferation, migration, and osteogenic differentiation. Moreover, metformin significantly enhanced the osteogenic ability of EVs on inflammatory PDLSCs. Animal experiments revealed that alveolar bone resorption was dramatically reduced in the EVs and M-EVs groups when compared to the periodontitis group, while the M-EVs group showed the lowest levels of alveolar bone loss. Metformin promoted the osteogenic differentiation of PDLSCs partly through EVs pathway and significantly enhanced the secretion of PDLSCs-EVs with superior pro-osteogenic and anti-inflammatory potential, thus improving EVs' therapeutic potential on periodontitis.

Nonlinear dynamic characteristics of modified variable hyperbolic circular arc tooth trace cylindrical gears

Nonlinear dynamic characteristics is one of the important performance indexes for the variable hyperbolic circular arc tooth trace (VH-CATT) cylindrical gear system. And accurate analysis of the nonlinear dynamic characteristics is of great significance to investigate service life of the VH-CATT cylindrical gear system. Therefore, the nonlinear dynamics study of the VH-CATT cylindrical gear is proposed. Firstly, the calculation methods or formulas of the time-varying stiffness, transmission error and meshing impact were given. Next, the mathematical model of the modified VH-CATT cylindrical gear was deduced based on the forming theory. Then, the controllable design model and tooth surface optimization design model were developed to calculate the best values of the modified parameters. Finally, a bending-torsion coupling dynamic model of the VH-CATT cylindrical gear pair was developed to investigate influence of the modification design on the nonlinear dynamic characteristics of the modified VH-CATT cylindrical gear, and the research conclusion was verified by the transmission experiments. Research shows that the tooth surface load reduces, the stiffness increases, the LTE and fluctuation range of the LTE decrease after modification. Modification makes the bifurcation diagram shift to the right and the complex motion of the unmodified VH-CATT cylindrical gear pair with the dimensionless frequency between 0.72 and 1.11 become a periodic motion. The vibration displacement of the modified VH-CATT cylindrical gear pair less than that of the unmodified VH-CATT cylindrical gear pair. The experiment also shows that the transmission error of the modified gear pair is less than that of the unmodified gear pair and the tooth surface modification design of the VH-CATT cylindrical gear improves the transmission efficiency. The tooth surface modification is beneficial to reduce the vibration and noise of the VH-CATT cylindrical gear pair. The research results provide a basis for improving the bearing capacity of the VH-CATT cylindrical gear.

Low-intensity pulsed ultrasound enhances the osteogenic potential of PDLSCs-derived extracellular vesicles through COMP/PI3K/AKT

The therapeutic potential of extracellular vesicles (EVs) in bone regeneration is noteworthy; however, their clinical application is impeded by low yield and limited efficacy. This study investigated the effect of low-intensity pulsed ultrasound (LIPUS) on the therapeutic efficacy of EVs derived from periodontal ligament stem cells (PDLSCs) and preliminarily explored its mechanism. PDLSCs were cultured with osteogenic media and stimulated with or without LIPUS, and then EVs and LIPUS-stimulated EVs (L-EVs) were isolated separately. We investigated the biological characteristics and effects of these two EVs on cell proliferation, migration, osteogenic differentiation, and bone regeneration in vivo and in vitro, and explored the potential mechanism by analyzing protein profiles. LIPUS significantly stimulated the secretion of PDLSCs-EVs, and L-EVs exhibited stronger efficacy in promoting cell proliferation, migration, and osteogenic differentiation, thereby enhancing new bone formation. LIPUS stimulation affected the protein profile of PDLSCs-EVs, and 42 proteins were upregulated and 4 proteins downregulated in L-EVs when compared with EVs. LIPUS significantly upregulated the level of cartilage oligomeric matrix protein (COMP) in EVs, which enhanced EVs' osteogenic ability via the PI3K/AKT pathway. This study proposes that LIPUS has potential as an optimization method for enhancing the therapeutic effects of EVs in tissue regeneration.