Corrigendum: Anomalous papillary muscle insertion into the mitral valve leaflet in hypertrophic obstructive cardiomyopathy: a lip nevus sign in echocardiography.

[This corrects the article DOI: 10.3389/fcvm.2023.1292142.].

Ferrous/Ferric Ions Crosslinked Type II Collagen Multifunctional Hydrogel for Advanced Osteoarthritis Treatment.

Osteoarthritis (OA) is a highly prevalent and intricate degenerative joint disease affecting an estimated 500 million individuals worldwide. Collagen-based hydrogels have sparked immense interest in cartilage tissue engineering, but substantial challenges persist in developing biocompatible and robust crosslinking strategies, as well as improving their effectiveness against the multifaceted nature of OA. Herein, a novel discovery wherein the simple incorporation of ferrous/ferric ions enables efficient dynamic crosslinking of type II collagen, leading to the development of injectable, self-healing hydrogels with 3D interconnected porous nanostructures, is unveiled. The ferrous/ferric ions crosslinked type II collagen hydrogels demonstrate exceptional physical properties, such as significantly enhanced mechanical strength, minimal swelling ratios, and remarkable resistance to degradation, while also exhibiting extraordinary biocompatibility and bioactivity, effectively promoting cell proliferation, adhesion, and chondrogenic differentiation. Additionally, the hydrogels reveal potent anti-inflammatory effects by upregulating anti-inflammatory cytokines while downregulating pro-inflammatory cytokines. In a rat model of cartilage defects, these hydrogels exhibit impressive efficacy, substantially accelerating cartilage tissue regeneration through enhanced collagen deposition and increased proteoglycan secretion. The innovative discovery of the multifunctional role of ferrous/ferric ions in endowing type II collagen hydrogels with a myriad of beneficial properties presents exciting prospects for developing advanced biomaterials with potential applications in OA.

Anomalous papillary muscle insertion into the mitral valve leaflet in hypertrophic obstructive cardiomyopathy: a lip nevus sign in echocardiography.

Background: Anomalous papillary muscle (APM) insertion into the mitral valve leaflet is rare but clinically important in hypertrophic obstructive cardiomyopathy (HOCM). In this study, we report the detection rate of APM insertion into the mitral valve using preoperative imaging modalities and the surgical outcomes of the patients. Methods: By retrospectively reviewing the clinical records of patients with HOCM who underwent surgical treatment by a single operation group at our center from January 2020 to June 2023, patients with APM insertion into the mitral valve leaflet were identified. Baseline data, image characteristics, and surgical outcomes were analyzed. Results: The incidence of APM insertion into the mitral valve leaflet was 5.1% (8/157). The insertion site was located at A3 in six cases, which was more common than at A2 (n = 2). Preoperative echocardiography was used to identify two patients (25%) with APM insertion. We observed a particular echocardiographic feature for APM in HOCM patients, which was noted as a "lip nevus sign", with a higher detection rate (62.5%). All patients successfully underwent septal myectomy with concomitant APM excision or mitral valve replacement via the transaortic (n = 5) or transmitral (n = 3) approach. The mean age was 49.0 ± 17.4 years and seven patients (87.5%) were female. Interventricular septum thickness (17.0 mm vs. 13.3 mm, P = 0.012) and left ventricular outflow gradient (117.5 mmHg vs. 7.5 mmHg, P = 0.012) were significantly decreased after surgery. Residual outflow obstruction, systolic anterior motion, and ≥3+ mitral regurgitation were negative. During the follow-up of 26.2 ± 12.2 months, there were no reported operations, adverse events, mitral regurgitation aggravations, recurrences of outflow obstruction, or instances of SAM. Conclusions: Papillary muscles inserted into the mitral valve leaflet are a subtype of subvalvular malformation in HOCM that requires surgical correction. The lip nevus sign on echocardiography is a characteristic of APM insertion in HOCM and may improve the preoperative detection rate. Adequate myectomy with anomalous papillary muscle excision has achieved good results in reducing the outflow gradient and eliminating mitral regurgitation, with good outcomes at short-to-intermediate follow-up.

Long-term outcomes of pulmonary atresia with ventricular septal defect by different initial rehabilitative surgical age.

Background: There is a lack of evidence guiding the surgical timing selection in pulmonary atresia with ventricular septal defect. This study aims to compare the long-term outcomes of different initial rehabilitative surgical ages in patients with pulmonary atresia with ventricular septal defect (PAVSD). Methods: From January 2011 to December 2020, a total of 101 PAVSD patients undergoing the initial rehabilitative surgery at our center were retrospectively reviewed. Receiver-operator characteristics curve analysis was used to identify the cutoff age of 6.4 months and therefore to classify the patients into two groups. Competing risk models were used to identify risk factors associated with complete repair. The probability of survival and complete repair were compared between the two groups using the Kaplan-Meier curve and cumulative incidence curve, respectively. Results: The median duration of follow-up was 72.76 months. There were similar ΔMcGoon ratio and ΔNakata index between the two groups. Multivariate analysis showed that age ≤6.4 months (hazard ratio (HR) = 2.728; 95% confidence interval (CI):1.122-6.637; p = 0.027) and right ventricle-to-pulmonary artery connection (HR = 4.196; 95% CI = 1.782-9.883; p = 0.001) were associated with increased probability of complete repair. The cumulative incidence curve showed that the estimated complete repair rates were 64% ± 8% after 3 years and 69% ± 8%% after 5 years in the younger group, significantly higher than 28% ± 6% after 3 years and 33% ± 6% after 5 years in the elder group (p < 0.001). There was no significant difference regarding the estimated survival rate between the two groups. Conclusion: Compared with those undergoing the initial rehabilitative surgery at the age >6.4 months, PAVSD patients at the age ≤6.4 months had an equal pulmonary vasculature development, a similar probability of survival but an improved probability of complete repair.

Efficient degradation of 2,4-dichlorophenol by heterogeneous electro-Fenton using bulk carbon aerogels modified in situ with FeCo-LDH as cathodes: Operational parameters and mechanism exploration.

In this study, an in situ grown FeCo-Layered double hydroxide anchored to the surface of a bulk carbon aerogel (FeCo-LDH/CA) for contaminant degradation during the heterogeneous electro-Fenton (EF) process. The results exhibited that the FeCo-LDH/CA cathode achieved 100% of 2,4-dichlorophenol (2,4-DCP = 20 mg/L) degradation within 120 min at pH = 3, application current 20 mA, and Na2SO4 concentration 0.05 M. Moreover, the degradation efficiency was impressive in the range of pH = 2-9. The coexistence of the Fe (III)/Fe (II) and Co (III)/Co (II) as active sites on the cathode surface promoted the in-situ decomposition of H2O2 to form reactive oxygen species (ROS). •OH and O2- were confirmed to be the major degradation pollutants of ROS. Furthermore, density functional theory (DFT) was used to predict the reaction sites of 2,4-DCP, and its possible degradation pathways were proposed. The toxicity of intermediate products was evaluated and decreased after degradation. In addition, the eight cycle experiments and the degradation of other typical contaminants demonstrated the satisfactory stability and applicability of the synthetic cathode. This study presents the preparation of an efficient and stable EF cathode, further promoting the application of iron-based composites in wastewater treatment.

The impact of mulberry leaf extract at three different levels on reducing the glycemic index of white bread.

In this study, the influences of mulberry leaf extract (MLE) addition on the physicochemical properties including the specific volume, texture and sensory features of white bread (WB) were evaluated by the sensory analysis technology. A double-blind, randomised, repeat-measure design was used to study the impact of MLE addition on the postprandial blood glucose response as well as the satiety index of WB. Results showed that the addition of MLE showed no significant effects on the physicochemical properties of WB except for the slight changes of color and bitterness. The addition of MLE significantly reduced the total blood glucose rise after ingestion of WB over 120 minutes, and reduced the GI value of WB in a dose-effect relationship. When the concentration of MLE reached 1.5 g per 100 g available carbohydrate, the GI value of WB could be reduced from 77 to 43. This study provides important information in terms of the appropriateness of MLE when added to more complex real food, the dose-dependent relationship could supply a reference for the application of MLE.

Outcomes of minimally invasive isolated tricuspid valve reoperation after left-side valve surgery: A single-center experience.

Background: Late severe tricuspid regurgitation (TR) after left-side valve surgery (LSVS) is not uncommon. However, the tricuspid valve has been deemed the forgotten valve because the isolated TR is well tolerated with medication, and reoperation has a higher rate of adverse events. With the advancement of minimally invasive techniques, isolated tricuspid valve reoperation (ITVR) via totally endoscopy or transcatheter approach brings the tricuspid valve into spotlight. Our aim is to report the safety and efficacy of minimally invasive ITVR using endoscopic and transcatheter approaches. Methods: From October 2020 to October 2021, 21 patients with LSVS history and secondary massive TR underwent minimally invasive ITVR in our institution. Baseline characteristics, surgical outcomes and follow-up results were analyzed, and data between the totally endoscopy approach and the transcatheter approach were compared. Results: Of the 21 cases, totally endoscopic isolated tricuspid valve surgery (EITVS) accounts for 16 (76.2%) cases, with 14 tricuspid valvuloplasty cases, and 2 tricuspid valve replacement cases; the remaining 5 (23.8%) cases underwent transcatheter tricuspid valve replacement (TTVR). The mean age was (60.0 ± 8.4) years, with 15 (71.4%) being female. Minimally invasive ITVR procedures were 100% successfully performed in all patients without any perioperative mortality, sternotomy conversion, or reoperation. During the median follow-up of 16.8 months (IQR, 13.0-20.6 months), New York Heart Association Class improved significantly from baseline (P = 0.004). TR severity was significantly improved during postoperative and follow-up period (both P < 0.001). Compared with the EITVS group, the TTVR group had a higher clinical risk score [8.00 (8.00, 9.00) vs. 5.00 (3.25, 5.00), P = 0.001], but a higher success rate in reducing TR to less than grade 1+ (100 vs. 43.8%, P = 0.045) at follow-up. Conclusion: In our series, minimally invasive ITVR, including EITVS and TTVR, is a safe and feasible option for severe TR after LSVS, and presents excellent early outcomes in selected patients. TTVR is a reliable alternative for patients with high surgical risk. To improve the results of ITVR, it is necessary to improve patient's preoperative status or perform reoperation before the onset of significant right heart failure. Further studies with a larger sample size and a longer follow-up period are awaited.

Generalized anxiety disorder among rural primary and middle school students during the outbreak of COVID-19: a multicenter study in three southern Chinese cities.

BACKGROUND: The major public health crisis caused by the rapid spread of the coronavirus disease 2019 (COVID-19) and the large-scale public health measures such as social isolation and school closures enforced by some countries have severely affected on the physical and mental wellbeing of children and adolescents globally. This study aimed to estimate the prevalence of the psychological impact and investigate the similarities and differences in the influential factors for generalized anxiety disorder among rural adolescents as a relatively lesser noticed population the outbreak of COVID-19. METHODS: From May 11 to 22, 2020, a total of 1,179 adolescents, including Grade 5-6 in primary school and Grade 7-8 in middle school, were selected by multistage sampling in three Southern Chinese cities (Shantou, Guangdong Province; Hezhou, Guangxi Province; Nanchong, Sichuan Province), and completed the questionnaires including sociodemographic, generalized anxiety disorder, academic stress, coronaphobia, knowledge of COVID-19, and precautionary measures. ANOVA, Chi-square test, Kruskalwallis H test and multivariate linear regression were performed in the statistical analysis. RESULTS: The average scores of generalized anxiety disorder during the past two weeks were 3.43 (SD 4.46), 4.47 (SD 5.15), and 4.10 (SD 4.94) in Shantou, Hezhou and Nanchong, respectively. For the pooled data, academic stress (P < 0.001), coronaphobia (P < 0.001), and precautionary measures (P = 0.002) contributed to the prediction of anxiety scores. Academic stress was significantly associated to anxiety symptoms in all cities (P all < 0.001). Coronaphobia was also significantly associated to anxiety symptoms in all cities (P all < 0.001). CONCLUSION: This study highlights the urgent need for researchers and policymakers to focus on the mental health of rural children and adolescents during the COVID-19 epidemic. The adolescents with academic stress and coronaphobia, the greater the risk that adolescents will suffer from anxiety, suggesting mental health counseling and professional family support are needed.

Microbiota affects mitochondria and immune cell infiltrations via alternative polyadenylation during postnatal heart development.

There is a growing body of evidence supporting the significant impact of microbiota on heart development. Alternative polyadenylation (APA) is a crucial mechanism for gene expression regulation and has been implicated in postnatal heart development. Nonetheless, whether microbiota can influence postnatal heart development through the regulation of APA remains unclear. Therefore, we conducted APA sequencing on heart tissues collected from specific pathogen-free (SPF) mice and germ-free (GF) mice at three different developmental stages: within the first 24 h after birth (P1), 7-day-old SPF mice, and 7-day-old GF mice. This approach allowed us to obtain a comprehensive genome-wide profile of APA sites in the heart tissue samples. In this study, we made a significant observation that GF mice exhibited noticeably longer 3' untranslated region (3' UTR) lengths. Furthermore, we confirmed significant alterations in the 3' UTR lengths of mitochondria-related genes, namely Rala, Timm13, and Uqcc3. Interestingly, the GF condition resulted in a marked decrease in mitochondrial cristae density and a reduction in the level of Tomm20 in postnatal hearts. Moreover, we discovered a connection between Rala and Src, which further implicated their association with other differentially expressed genes (DEGs). Notably, most of the DEGs were significantly downregulated in GF mice, with the exceptions being Thbs1 and Egr1. Importantly, the GF condition demonstrated a correlation with a lower infiltration of immune cells, whereby the levels of resting NK cells, Th17 cells, immature dendritic cells, and plasma cells in GF mice were comparable to those observed in P1 mice. Furthermore, we established significant correlations between these immune cells and Rala as well as the related DEGs. Our findings clearly indicated that microbiota plays a vital role in postnatal heart development by affecting APA switching, mitochondria and immune cell infiltrations.

Mitral Valve Replacement Adopting Chimney Technique in Mitral Insufficiency And Extensive Mitral Annular Calcification: A Case Report.

Extensive and serious mitral annular calcification represents a troublesome obstacle in intracardiac mitral valve replacement due to time-consuming requirements and the potential of decalcification-associated complications. We report the case of a high-risk patient with extremely severe mitral insufficiency and difficult-to-debride annular calcification who received mitral replacement using a chimney technique. This approach enabled not only the minimization of mitral calcification debridement but also the reduction of surgery time. Consequently, the surgery was successful with a great postoperative outcome. Thus, this technique is a safe and feasible option to deal with intractable mitral annular calcification during mitral valve surgery.

Case report: Total thoracoscopic repair of sinus of Valsalva aneurysm combined with ventricular septal defect.

The sinus of Valsalva aneurysm (SVA) is a rare cardiac anomaly. It can develop into the heart failure if it ruptures, which requires early intervention. However, such congenital anomalies are usually treated using a median sternotomy approach. Here, we report a rare case of SVA combined with a ventricular septal defect in which the patient underwent patch repair of the defects under a total thoracoscopy approach. She was discharged uneventfully and showed no residual shunt or aortic regurgitation postoperatively or at the 12-month follow-up. The total thoracoscopic approach for SVA repair is technically feasible.

Two-photon endomicroscopy with microsphere-spliced double-cladding antiresonant fiber for resolution enhancement.

We demonstrate a miniature fiber-optic two two-photon endomicroscopy with microsphere-spliced double-cladding antiresonant fiber for resolution enhancement. An easy-to-operate process for fixing microsphere permanently in an antiresonant fiber core, by arc discharge, is proposed. The flexible fiber-optic probe is integrated with a parameter of 5.8 mm × 49.1 mm (outer diameter × rigid length); the field of view is 210 µm, the resolution is 1.3 µm, and the frame rate is 0.7 fps. The imaging ability is verified using ex-vivo mouse kidney, heart, stomach, tail tendon, and in-vivo brain neural imaging.

Complications and management of functional single ventricle patients with Fontan circulation: From surgeon's point of view.

Fontan surgery by step-wise completing the isolation of originally mixed pulmonary and systemic circulation provides an operative approach for functional single-ventricle patients not amenable to biventricular repair and allows their survival into adulthood. In the absence of a subpulmonic pumping chamber, however, the unphysiological Fontan circulation consequently results in diminished cardiac output and elevated central venous pressure, in which multiple short-term or long-term complications may develop. Current understanding of the Fontan-associated complications, particularly toward etiology and pathophysiology, is extremely incomplete. What's more, ongoing efforts have been made to manage these complications to weaken the Fontan-associated adverse impact and improve the life quality, but strategies are ill-defined. Herein, this review summarizes recent studies on cardiac and non-cardiac complications associated with Fontan circulation, focusing on significance or severity, etiology, pathophysiology, prevalence, risk factors, surveillance, or diagnosis. From the perspective of surgeons, we also discuss the management of the Fontan circulation based on current evidence, including post-operative administration of antithrombotic agents, ablation, pacemaker implantation, mechanical circulatory support, and final orthotopic heart transplantation, etc., to standardize diagnosis and treatment in the future.

Primeval outcomes of thoracoscopic transmitral myectomy with anterior mitral leaflet extension for hypertrophic obstructive cardiomyopathy.

BACKGROUND: The transaortic Morrow procedure is the current gold standard for hypertrophic obstructive cardiomyopathy (HOCM) patients who are resistant to maximum drug therapy. It is controversial whether concomitant mitral valve intervention is necessary. Only a few centers apply for concomitant anterior mitral leaflet extension with a bovine or autologous pericardial patch to further decrease systolic anterior motion. Our aim is to assess the primeval outcomes of thoracoscopic transmitral myectomy with anterior mitral leaflet extension (TTM-AMLE) in symptomatic HOCM patients. METHODS: Between April 2019 and November 2020, 18 consecutive HOCM patients who underwent TTM-AMLE were enrolled in this study. Preoperative, postoperative, and follow-up outcomes were compared and statistically analyzed. RESULTS: The mean age was (50.17 ± 6.18) years and 10 (55.56%) were males. 18 (100%) patients had mitral regurgitation preoperatively, and they all successfully underwent TTM-AMLE with a median cardiopulmonary bypass and aortic cross-clamp time of 200.0 (150.8, 232.0), and 127.5 (116.0, 149.0) min, respectively. The median length of ICU stay was 2.7 (1.4, 5.2) days. The interventricular septum thickness was significantly reduced (from 18.03 ± 3.02 mm to 11.91 ± 1.66 mm, p < .001). There was no perioperative mortality, perforation of ventricular septum, or conversion to sternotomy observed. During a median follow-up of 18 months (IQR, 5-24 months), 1 (5.56%) patient had severe mitral regurgitation due to patch detachment and received reoperation. Moderate degree of mitral regurgitation and more than 50 mmHg in left ventricular outflow tract gradient were found in 2 (11.11%), and 1 (5.56%) patients, respectively. 1 (5.56%) patient who had second-degree atrioventricular block received permanent pacemaker implantation postoperatively. Overall, the maximum left ventricular outflow tract gradient (88.50 [59.50, 112.75] mmHg vs. 10.50 [7.00, 15.50] mmHg, p = .002), left ventricular outflow tract velocity (4.70 [3.86, 5.33] m/s vs. 1.60 [1.33, 1.95] m/s, p < .001) and the degree of mitral regurgitation (6.99 ± 4.47 cm2 vs. 2.22 ± 1.51 cm2 , p = .001) were significantly decreased, with a significant reduction in the proportion of systolic anterior motion (94.44% vs. 16.67%, p < .001). CONCLUSIONS: The TTM-AMLE is a safe and effective surgical approach for selected patients with HOCM. In our series, it provides excellent relief of left ventricular outflow tract obstruction, while significantly eliminating mitral regurgitation. The early outcomes of TTM-AMLE are satisfactory, but further studies and longer follow-ups are awaited.

Apple-like Zinc-Oxide Mesocrystals as Robust and Versatile Photocatalysts for Efficient Degradation of Eight Different Organic Dyes.

The discovery of efficient photocatalysts is a promising key approach to solve the environmental crisis caused by hazardous organic dyes. Herein, we have for the first time created ZnO mesocrystals with a novel apple-like morphology. We have developed a one-pot biomineralization route to synthesize ZnO nanostructures at room temperature by using the rod-like protein collagen as the template. The shape of ZnO mesocrystals can be conveniently tuned from fusiform-like and kiwi-like to orange-like, apple-like, and snack-like structures. The apple-like ZnO mesocrystals show a significantly better photodegradation efficiency than the commercial ZnO powder as well as other nanostructured ZnO materials for both rhodamine B (RhB) and methyl orange (MO). Furthermore, the apple-like zinc-oxide mesocrystals can degrade all of the tested eight different types of organic dyes (RhB, rhodamine 6G, methylene blue, Coomassie brilliant blue R250, BPB, MO, Li Chunhong S, and carmine) simply under the exposure of sunlight, demonstrating their superior photodegradation prowess, environmental amiability, and energy-saving features. The novel robust and versatile photocatalyst has greatly advanced our abilities for the elimination of organic dyes. The green, one-pot strategy provides a convenient method for the construction of novel metal-oxide nanostructures with promising applications in environmental protection.

End-diastolic forward flow in repaired tetralogy of Fallot: Mid-term outcomes from a single center.

Background: Pulmonary arterial end-diastolic forward flow (EDFF) following repaired tetralogy of Fallot (rTOF) is recognized as right ventricular (RV) restrictive physiology, which is closely related to poor prognosis. This study sought to review mid-term experience and investigate the risk factors of EDFF in the rTOF patients. Methods: From September 2016 to January 2019, 100 patients (age < 18 years old) who underwent complete tetralogy of Fallot (TOF) repair were enrolled and were divided into EDFF group (n = 52) and non-EDFF group (n = 48) based on the presence of postoperative EDFF. Elastic net analysis was performed for variable selection. Univariate and multivariate logistic analyses were used to analyze the correlation between risk factors and EDFF. Results: End-diastolic forward flow group had lower systolic blood pressure (P = 0.037), diastolic blood pressure (P = 0.027), and higher vasoactive-inotrope score within 24 h after surgery (P = 0.022) than non-EDFF group. Transannular patch (TAP) was an independent predictor of postoperative EDFF [P = 0.029, OR: 2.585 (1.102∼6.061)]. Patients were followed up for a median of 2.6 years [interquartile range (IQR) 1.6] after the first TOF repair. During follow-up, the prevalence of the EDFF was lower in those with pulmonary valve (PV) reconstructions than that in those undergoing patch enlargement without PV reconstructions in the primary TOF repair (P < 0.001). Conclusion: End-diastolic forward flow was associated with TAP. Patients with EDFF might have a transient hemodynamic instability in the early postoperative period. PV reconstructions in the TOF repair might reduce the incidence of EDFF in the mid-term follow-up.

Surfactant-free self-assembly to the synthesis of MoO3 nanoparticles on mesoporous SiO2 to form MoO3/SiO2 nanosphere networks with excellent oxidative desulfurization catalytic performance.

Recently, oxidative desulfurization (ODS) is favoured by researchers because it is based on mild conditions and does not consume hydrogen. However, the preparation process of catalyst for ODS was not green or costly, which limits its further industrial applications. In this study, a facile route has been explored to grow the mesoporous MoO3/SiO2 nanosphere networks (MoO3/SiO2 NN) using low-cost air without surfactants. Herein, the air not only served as the template to self-assemble and form the nanosphere network structure but acted as a mesopore-directing agent to make mesopores on the MoO3/SiO2 nanosphere. Moreover, the recovered waste mother liquor was also successfully applied to prepare nanomaterials. Gratifyingly, the nanocomposites of MoO3/SiO2 NN displayed remarkable pore structure, large specific surface area (201 m2  g-1) and excellent amphipathy (CA = 24.7° and 13.6° of water and n-octane, respectively) making it a promising catalyst for two-phase ODS reaction with H2O2 as an oxidant. Meanwhile, the high TOF value (56.6 h-1) and outstanding durability were obtained under optimum conditions (Yield > 99 % at 70 °C and O/S = 8:1 for 1 h, 20 mg catalyst) and the products were detected by GC-MS and 1H NMR. Therefore, an environmentally benign self-assembly procedure can facilely prepare more types of mesoporous catalysts for large-scale industrial application.

Composition and Mechanism of Three-Dimensional Hydrogel System in Regulating Stem Cell Fate.

Three-dimensional (3D) hydrogel systems integrating different types of stem cells and scaffolding biomaterials have an important application in tissue engineering. The biomimetic hydrogels that pattern cell suspensions within 3D configurations of biomaterial networks allow for the transport of bioactive factors and mimic the stem cell niche in vivo, thereby supporting the proliferation and differentiation of stem cells. The composition of a 3D hydrogel system determines the physical and chemical characteristics that regulate stem cell function through a biological mechanism. Here, we discuss the natural and synthetic hydrogel compositions that have been employed in 3D scaffolding, focusing on their characteristics, fabrication, biocompatibility, and regulatory effects on stem cell proliferation and differentiation. We also discuss the regulatory mechanisms of cell-matrix interaction and cell-cell interaction in stem cell activities in various types of 3D hydrogel systems. Understanding hydrogel compositions and their cellular mechanisms can yield insights into how scaffolding biomaterials and stem cells interact and can lead to the development of novel hydrogel systems of stem cells in tissue engineering and stem cell-based regenerative medicine. Impact statement Three-dimensional hydrogel system of stem cell mimicking the stemcell niche holds significant promise in tissue engineering and regenerative medicine. Exactly how hydrogel composition regulates stem cell fate is not well understood. This review focuses on the composition of hydrogel, and how the hydrogel composition and its properties regulate the stem cell adhesion, growth, and differentiation. We propose that cell-matrix interaction and cell-cell interaction are important regulatory mechanisms in stem cell activities. Our review provides key insights into how the hydrogel composition regulates the stem cell fate, untangling the engineering of three-dimensional hydrogel systems for stem cells.