Effects of Calcination Temperature on the Synthesis of One-Pot Sol-Gelled Barium Titanate Powder and Its Performance as an Endodontic Radiopacifier.

Barium titanate (BaTiO3, BTO), conventionally used for dielectric and ferroelectric applications, has been assessed for biomedical applications, such as its utilization as a radiopacifier in mineral trioxide aggregates (MTA) for endodontic treatment. In the present study, BTO powders were prepared using the sol-gel process, followed by calcination at 400-1100 °C. The X-ray diffraction technique was then used to examine the as-prepared powders to elucidate the effect of calcination on the phase composition and crystalline size of BTO. Calcined BTO powders were then used as radiopacifiers for MTA. MTA-like cements were investigated to determine the optimal calcination temperature based on the radiopacity and diametral tensile strength (DTS). The experimental results showed that the formation of BTO phase was observed after calcination at temperatures of 600 °C and above. The calcined powders were a mixture of BaTiO3 phase with residual BaCO3 and/or Ba2TiO4 phases. The performance of MTA-like cements with BTO addition increased with increasing calcination temperature up to 1000 °C. The radiopacity, however, decreased after 7 days of simulated oral environmental storage, whereas an increase in DTS was observed. Optimal MTA-like cement was obtained by adding 40 wt.% 1000 °C-calcined BTO powder, with its resulting radiopacity and DTS at 4.83 ± 0.61 mmAl and 2.86 ± 0.33 MPa, respectively. After 7 days, the radiopacity decreased slightly to 4.69 ± 0.51 mmAl, accompanied by an increase in DTS to 3.13 ± 0.70 MPa. The optimal cement was biocompatible and verified using MG 63 and L929 cell lines, which exhibited cell viability higher than 95%.

Live cell pool and rare cell isolation using Enrich TROVO system.

Although several technologies have been developed to isolate cells of interest from a heterogenous sample, clogging and impaired cell viability limit such isolation. We have developed the Enrich TROVO system as a novel, nonfluidic technology to sort live cells. The TROVO system combines imaging-based cell selection and photo-crosslinking of (gelatin methacrylate) gelMA-hydrogel to capture cells. After capture, cells are released by enzymatic digestion of the hydrogel and then retrieved for downstream analysis or further cell culturing. The system can capture cells with a recovery rate of 48% while maintaining 90% viability. Moreover, TROVO can enrich rare cells 506-fold with 93% efficiency using single step isolation from a 1:104 cell mixture, and can also capture one target cell from 1 million cells, reaching an enrichment ratio of 9128. In addition, 100% purity and 49% recovery rate can be achieved by a following negative isolation process. Compared to existing technologies, the TROVO system is clog-resistant, highly biocompatible, and can process a wide range of sample sizes.

Design and Fabrication of Enzymatic Potentiometric Biosensor Based on Flexible Printed Circuit Board for Glucose Detection.

This study investigated the development and optimization of a flexible printed circuit board-based glucose biosensor with an emphasis on high sensitivity, selectivity, and overall performance. Advances in glucose biosensing have highlighted its importance in medical diagnostics, especially diabetes management. The fabrication process involves depositing a RuO2 sensing film on a flexible printed circuit board (FPCB) by radio frequency sputtering. Enzyme-based modification using glucose oxidase (GOx), (3-aminopropyl) triethoxysilane (APTES), and glutaraldehyde (GA) to enhance selectivity and catalytic reactions. And through Scanning Electron Microscopy and electrochemical impedance spectroscopy, the sensing film, and the effect of modification on the charge transfer rate and performance improvement were analyzed. This glucose biosensor has excellent linearity, sensitivity, and reproducibility. The study also assessed response time and selectivity. The response time efficiency of the biosensor solidified its utility in point-of-care monitoring, while selectivity experiments validated its ability to distinguish glucose from interfering substances, ensuring accuracy in practical applications. According to the experimental results, the enzymatic glucose biosensor has the best average sensitivity and linearity of 44.42 mV/mM and 0.999 with a response time of 6 seconds.

In vivo detection of poststroke cerebral cell proliferation in rodents and humans.

OBJECTIVE: F-18-fluorothymidine (FLT) is a positron emission tomography (PET) tracer for imaging cell proliferation in vivo. We aimed to assess FLT uptake as a marker for cerebral cell proliferation in a rat model of ischemic stroke and patients with cerebral infarct, correlating with disease severity and outcomes. METHODS: Cerebral FLT PET was performed in rats subjected to transient middle cerebral artery occlusion (MCAO) and patients with cerebral infarct. PET data were analyzed and expressed as average standardized uptake value ratios (SUVRs) using cerebellar cortex as reference. Infarct volume was analyzed by 2,3,5-triphenyltetrazolium chloride staining in rats and by magnetic resonance imaging in patients. Neurological function was assessed using modified Neurological Severity Score (mNSS) for rats and National Institutes of Health Stroke Scale (NIHSS) for patients. RESULTS: Seven days post-MCAO, rats' FLT PET displayed higher SUVRs in the infarcted brain, declining gradually until Day 28. FLT-binding ratio (SUVR in the infarcted brain divided by that in contralateral side) correlated positively with stroke severity (p < 0.001), and to early mNSS decline in rats with mild to moderate stroke severity (p = 0.031). In 13 patients with cerebral infarct, FLT PET showed high SUVR in the infarcted regions. FLT-binding ratio correlated positively with infarct volume (p = 0.006). Age-adjusted initial NIHSS (p = 0.035) and early NIHSS decline (p = 0.076) showed significance or a trend toward positive correlation with the FLT-binding ratio. INTERPRETATION: In vivo FLT PET detects poststroke cerebral cell proliferation, which is associated with stroke severity and/or outcomes in MCAO rats and patients with cerebral infarct.

Selective expansion of target cells using the Enrich TROVO platform.

Enriching target cell clones from diverse cell populations is vital for many life science applications. We have developed a novel method to rapidly and efficiently purify specific clonal cell populations from a larger, heterogeneous group using the Enrich TroVo system (Enrich Biosystems Inc., CT, USA). This system takes advantage of microfabrication and optical technologies by utilizing small hydrogel wells to separate desired cell populations and an innovative patching technique to selectively eliminate undesired cells. This method allows the isolation and growth of desired cells with minimal impact on their viability and proliferation. We successfully isolated and expanded clonal cell populations of desired cells using two model cells. Compared with fluorescence-activated cell sorting, Enrich TroVo system offers a promising alternative for isolating of sensitive, adherent cells, that is, patient-derived cells.

Improved electrical properties of micro light-emitting diode displays by ion implantation technology.

Generally, the inductively coupled plasma-reactive ion etching (ICP-RIE) mesa technology was used to remove p-GaN/MQWs and expose n-GaN for electrical contact in a fabricated micro light-emitting diode (µLED). In this process, the exposed sidewalls were significantly damaged which result in small-sized µLED presenting a strong size-dependent influence. Lower emission intensity was observed in the µLED chip, which can be attributed to the effect of sidewall defect during etch processing. To reduce the non-radiative recombination, the ion implantation using an As+ source to substitute the ICP-RIE mesa process was introduced in this study. The ion implantation technology was used to isolate each chip to achieve the mesa process in the µLED fabrication. Finally, the As+ implant energy was optimized at 40 keV, which exhibited excellent current-voltage characteristics, including low forward voltage (3.2 V @1 mA) and low leakage current (10-9 A@- 5 V) of InGaN blue µLEDs. The gradual multi-energy implantation process from 10 to 40 keV can further improve the electrical properties (3.1 V @1 mA) of µLEDs, and the leakage current was also maintained at 10-9 A@- 5 V.

ATM Inhibition-Induced ISG15/IFI27/OASL Is Correlated with Immunotherapy Response and Inflamed Immunophenotype.

Immune checkpoint blockade (ICB) therapy can improve the survival of cancer patients with a high tumor mutation burden (TMB-H) or deficiency in DNA mismatch repair (dMMR) in their tumors. However, most cancer patients without TMB-H and dMMR do not benefit from ICB therapy. The inhibition of ATM can increase DNA damage and activate the interferon response, thus modulating the tumor immune microenvironment (TIME) and the efficacy of ICB therapy. In this study, we showed that ATM inhibition activated interferon signaling and induced interferon-stimulated genes (ISGs) in cisplatin-resistant and parent cancer cells. The ISGs induced by ATM inhibition were correlated with survival in cancer patients who received ICB therapy. In oral cancer, high expressions of ISG15, IFI27, and OASL were associated with low expressions of ATM, the activation of inflamed immune pathways, and increased tumor-infiltrating scores of CD8+ T, natural killer, and dendritic cells. The high expressions of ISG15, IFI27, and OASL were also correlated with complete remission in patients with cervical cancer treated with cisplatin. These results suggest that ATM inhibition can induce the interferon response and inflamed TIME, which may benefit ICB therapy.

Comparing outcomes of ovarian cystectomy by vaginal natural orifice transluminal endoscopic surgery versus laparoendoscopic single-site surgery: A retrospective cohort study.

BACKGROUND: We aimed to compare the outcomes of ovarian cystectomy (OC) performed by vaginal natural orifice transluminal endoscopic surgery (vNOTES) vs transumbilical laparoendoscopic single-site surgery (LESS). METHODS: We retrospectively analyzed the data of patients in our hospital who underwent OC either by vNOTES or LESS between January 2015 and September 2021. Demographic data were collected. The primary outcome was the conversion rate. The secondary outcomes were the duration of surgery, length of hospital stay, estimated blood loss, maximum body temperature within 48 hours after operation, and duration of maximum body temperature (hours), among others. Statistical analysis was done using the SPSS software. RESULTS: Exactly 284 patients were screened. The vNOTES and LESS groups consisted of 21 and 47 patients, respectively. There was no significant difference in the conversion rates between the two groups (0 vs 8.5% in vNOTES and LESS, respectively; p = 0.303). Compared with the vNOTES group, the LESS group had a larger cyst diameter (6.00 ± 2.32 vs 4.69 ± 1.29 cm; p = 0.004), more endometriotic cysts (42.6% vs 9.5%; p < 0.001), and more pelvic adhesions requiring adhesiolysis (57.4% vs 19.0%; p = 0.003). At baseline, there were no other differences between the groups. The secondary outcomes included a shorter duration of surgery (70.14 ± 27.30 vs 99.57 ± 36.26 minutes; p = 0.001) and lower estimated blood loss (64.29 ± 39.19 vs 163.43 ± 251.20 mL; p = 0.011) in the vNOTES group. Regression analysis showed the diameter of the ovarian cyst correlated with surgical time. The complication was comparable between the two groups. CONCLUSION: Above all, the advantages of vNOTES include an absence of visible scars, shorter surgical duration, and less blood loss when compared with LESS. Further large-scale prospective trials should confirm the results of our study.

Design and Measurement of Microelectromechanical Three-Axis Magnetic Field Sensors Based on the CMOS Technique.

The design, fabrication, and measurement of a microelectromechanical system (MEMS) three-axis magnetic field sensor (MFS) based on the commercial complementary metal oxide semiconductor (CMOS) process are investigated. The MFS is a magnetic transistor type. The performance of the MFS was analyzed employing the semiconductor simulation software, Sentaurus TCAD. In order to decrease the cross-sensitivity of the three-axis MFS, the structure of the MFS is planed to accommodate two independent sensing components, a z-MFS utilized to sense magnetic field (M-F) in the z-direction and a y/x-MFS composed of a y-MFS and a x-MFS to be utilized to sense M-F in the y- and x-directions. The z-MFS incorporates four additional collectors to increase its sensitivity. The commercial 1P6M 0.18 µm CMOS process of the Taiwan Semiconductor Manufacturing Company (TSMC) is utilized to manufacture the MFS. Experiments depict that the MFS has a low cross-sensitivity of less than 3%. The sensitivities of z-, y-, and x-MFS are 237 mV/T, 485 mV/T, and 484 mV/T, respectively.

Risk Factors for Treatment Failure in Skin and Soft Tissue Infections Caused by Nontuberculous Mycobacteria.

BACKGROUND: This study investigated the characteristics of patients with skin and soft tissue infections (SSTIs) caused by nontuberculous mycobacteria (NTM) and identified the risk factors for treatment failure in these patients. MATERIAL AND METHODS: Data of patients with NTM SSTIs who received treatment between January 2014 and December 2019 at Taipei Veterans General Hospital were collected retrospectively. Possible risk factors were determined using univariate and multivariate analysis with logistic regression models. RESULTS: A total of 47 patients (24 male, 23 female; age, 57.1 ± 15.2 years) were enrolled. Type 2 diabetes mellitus was the most common comorbidity. The most common mycobacterial species was the Mycobacterium abscessus complex, and the most commonly affected site was the axial trunk. Treatment was successful in 38 patients (81%). Six patients had recurrent infections (13%) after the treatment course was completed, and 3 patients (6.4%) died of NTM-related infection. Delayed treatment for more than 2 months and antibiotic-alone treatment were 2 independent risk factors for treatment failure of NTM SSTIs. CONCLUSIONS: Delayed treatment for more than 2 months and antibiotic-alone treatment were associated with a higher failure rate in patients with NTM SSTIs. Therefore, the differential diagnosis of NTM infection should always be considered when the treatment course is prolonged but not effective. Early identification of causative NTM species and appropriate antibiotic treatment may lower the risk of treatment failure. Prompt surgical treatment is suggested if available.

The Addition of a Temporary Intramedullary K-wire to Facilitate Plating for Metacarpal Fractures.

Open reduction internal fixation with plate fixation is commonly used in treating metacarpal fractures to facilitate early rehabilitation. However, it is sometimes challenging to maintain a satisfactory 3-dimensional alignment during the plating process. We present a method using a temporary centrally placed intramedullary k-wire to maintain a fundamental stability for reduction of metacarpal fractures. This method facilitates the plating process and simplifies the open reduction internal fixation of the metacarpal fractures.

Transient ischemic attack after mRNA-based COVID-19 vaccination during pregnancy: A case report.

BACKGROUND: Thrombocytopenia with thrombosis syndrome has been reported after vaccination against severe acute respiratory syndrome coronavirus 2 with two mRNA vaccines. The syndrome is characterized by thrombosis, especially cerebral venous sinus thrombosis, and may lead to stroke. Pregnant women with stroke show higher rates of pregnancy loss and experience serious pregnancy complications. We present the case of a 24-year-old pregnant woman with a transient ischemic attack (TIA) that developed after vaccination with the Moderna mRNA-1273 vaccine (at 37 2/7 wk). CASE SUMMARY: TIA occurred 13 d following the coronavirus disease vaccination. At 39 1/7 wk of pregnancy, the patient presented with sudden onset of right eye blurred vision with headache, dizziness with nausea, right-hand weakness, anomia, and alexia. The symptoms lasted 3 h; TIA was diagnosed. Blood test results revealed elevated D-dimer, cholesterol, and triglyceride levels. Brain magnetic resonance imaging showed no acute hemorrhagic or ischemic stroke. At pregnancy 37 6/7 wk, she was admitted for cesarean delivery to reduce subsequent risk of stroke during labor. Body mass index on admission was 19.8 kg/m2. Magnetic resonance angiography and transesophageal echocardiography showed no abnormalities. The next day, a mature female baby weighing 2895 g and measuring 50 cm was delivered. Apgar scores were 8 and 9 in the first and fifth minutes. D-dimer levels decreased on postoperative day 4. After discharge, the autoimmune panel was within normal limits, including antinuclear and antiphospholipid antibodies. CONCLUSION: TIA might be developed after the mRNA vaccines in pregnant women.

Demonstration of a side-pumped cross-seeded thin-slab pre-amplifier for high-power Ti:Sa laser systems.

We demonstrate a room-temperature Ti:Sapphire (Ti:Sa) amplifier that uses a cross pump-seed geometry (cross-thin-slab) to generate 30-mJ output pulses at 0.5-kHz repetition rate, and 25 mJ at 1 kHz when pumped by 100-mJ, 515-nm pulses from a diode-pumped Yb:YAG laser. The geometry allows to maintain a crystal temperature of ∼30°C using cooling water at 10°C. The amplifier is an attractive solution for use in the first stages of amplification in high peak and high average power chirped pulse amplification laser systems.

Development of di(2-ethylhexyl) phthalate-containing thioglycolic acid immobilized chitosan mucoadhesive gel as an alternative hormone therapy for menopausal syndrome.

Menopausal syndrome includes the symptoms that most women experience owing to hormone changes after menopause. Although hormone replacement therapy is a common treatment for menopausal syndrome, there are still many side effects and challenges hindering research. In this study, thioglycolic acid (TGA)-immobilized chitosan mucoadhesive gel was synthesized by a new method of low concentration of 1,4-butanediol diglycidyl ether (BDDE) would encapsulate di(2-ethylhexyl) phthalate (DEHP) as an alternative hormone replacement therapy for menopausal syndrome. The efficacies of the DEHP-containing TGA-chitosan gel (CT-D) were confirmed and evaluated by materials characterization and in vitro study. Results showed that CT-D was not cytotoxic and had better mucoadhesive ability than chitosan. The animal model was constructed 1 month after bilateral ovariectomy in SD rats. CT-D was administered intravaginally every 3 days. Bodyweight, wet weight of the uterus and vagina, vaginal smears, histology, blood element analysis, and serological analysis was used to assess the ability of the material to relieve menopausal syndrome. The results indicated that the combination of the sustained release of DEHP and mucoadhesive TGA-immobilized chitosan allows the developed CT-D to relieve the menopausal syndrome through low concentrations of DEHP, which falls in the safety level of the tolerable daily intake of DEHP.

Engineered cell-laden thermosensitive poly(N-isopropylacrylamide)-immobilized gelatin microspheres as 3D cell carriers for regenerative medicine.

Several studies have focused on using cell carriers to solve the problem of mesenchymal stem cell expansion on regenerative medicine. However, the disadvantages of using prolonged enzymatic treatment and low cell harvest efficiency still trouble researchers. In this study, PNIPAAm-immobilized gelatin microspheres (abbreviated as GNMS) were synthesized using a simple power-driven flow-focusing microinjection system. The developed thermosensitive GNMS can allow easier harvesting of cells from the microspheres, requiring only 10 â€‹min of low-temperature treatment and 5 â€‹min of trypsin treatment. The developed GNMS was characterized by Fourier-transform infrared spectroscopy, optical microscopy, and scanning electron microscopy. Further, live/dead staining, F-actin staining, and PrestoBlue cell viability assays were used to evaluate cytotoxicity, cell morphology, cell proliferation, and harvest efficiency. The gene expression of stem cell markers was determined by real-time quantitative PCR (Q-PCR) analysis to investigate the stemness and phenotypic changes in Wharton's jelly-derived mesenchymal stem cells. The results showed that the engineered cell-laden thermosensitive GNMS could significantly increase the cell harvest rate with over 99% cell survival rate and no change in the cell phenotype. Thus, the described strategy GNMS could be the suitable 3D cell carriers in the therapeutic application and opens new avenues for regenerative medicine.

The Production of Fat-Containing Cultured Meat by Stacking Aligned Muscle Layers and Adipose Layers Formed From Gelatin-Soymilk Scaffold.

Tissue engineered cultured meat has been proposed as an emerging innovative process for meat production to overcome the severe consequences of livestock farming, climate change, and an increasing global population. However, currently, cultured meat lacks organized tissue structure, possesses insufficient fat content, and incurs high production costs, which are the major ongoing challenges. In this study, a developed scaffold was synthesized using gelatin and soymilk to create a friendly environment for myogenesis and adipogenesis in C2C12 and 3T3-L1 cells, respectively. The fat containing cultured meat was fabricated with an aligned muscle-like layer and adipose-like layer by stacking these layers alternately. The muscle-like layer expressing myosin and the adipose-like layer abundant in fat were sandwiched to form fat containing muscle tissue. The cytotoxicity and cell survival rate were evaluated using the WST-1 assay and live/dead staining. Myogenesis was confirmed by the expression of myogenin and myosin. The myotubes, myofibrils, and sarcomeres were observed under an inverted microscope, fluorescence microscope, and scanning electron microscope. Adipogenesis was evaluated by protein expression of the peroxisome proliferator-activated receptor γ, and oil droplet accumulation was determined by fluorescence microscopy with Nile Red stain. Extracellular matrix secretion was examined by safranin-O staining. In this study, the cultured meat was prepared with muscle-like texture with the addition of pre-adipocyte, where the multilayered muscle-like tissues with fat content would produce juicy cultured meat.

Real-world Afatinib Outcomes in Advanced Non-small Cell Lung Cancer Harboring EGFR Mutations.

BACKGROUND/AIM: Afatinib is a standard treatment for patients with advanced non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. Osimertinib can overcome the treatment resistance-associated EGFR T790M mutation, and the sequence of afatinib followed by osimertinib is an effective therapeutic strategy for NSCLC patients. This study comprehensively evaluated the outcomes of sequential therapy following frontline afatinib and identified predictive factors for T790M mutation acquisition. PATIENTS AND METHODS: Data from patients with advanced NSCLC treated with frontline afatinib at a Taiwanese hospital group from June 2014 to March 2018 were retrospectively reviewed. The EGFR T790M mutation was detected by tissue sequencing or liquid biopsy. The patients' clinicopathological features were collected, and univariate and multivariate analyses were performed to identify potential predictive and prognostic factors. RESULTS: A total of 635 patients treated with afatinib were enrolled in this study. Until August 2021, 553 patients experienced progression, and 225 patients underwent T790M mutation testing. The T790M positive rate was 54.2%. Both exon 19 deletion and progression-free survival were associated with T790M positivity. Osimertinib was found to be effective in T790M-positive but not T790M-negative NSCLC. The median overall survival (OS) was 61.8 months for patients with T790M mutation undergoing later-line osimertinib compared with 30.1 months for patients without T790M mutation undergoing chemotherapy only. Osimertinib independently prolonged OS after afatinib progression. CONCLUSION: This study confirmed the efficacy of sequential afatinib and osimertinib treatment. T790M mutation detection and osimertinib availability are important for prolonging survival in patients with NSCLC harboring EGFR mutations.

Natural Compounds Targeting Cancer-Associated Fibroblasts against Digestive System Tumor Progression: Therapeutic Insights.

Cancer-associated fibroblasts (CAFs) are critical for cancer occurrence and progression in the tumor microenvironment (TME), due to their versatile roles in extracellular matrix remodeling, tumor-stroma crosstalk, immunomodulation, and angiogenesis. CAFs are the most abundant stromal component in the TME and undergo epigenetic modification and abnormal signaling cascade activation, such as transforming growth factor-ß (TGF-ß) and Wnt pathways that maintain the distinct phenotype of CAFs, which differs from normal fibroblasts. CAFs have been considered therapeutic targets due to their putative oncogenic functions. Current digestive system cancer treatment strategies often result in lower survival outcomes and fail to prevent cancer progression; therefore, comprehensive characterization of the tumor-promoting and -restraining CAF activities might facilitate the design of new therapeutic approaches. In this review, we summarize the enormous literature on natural compounds that mediate the crosstalk of CAFs with digestive system cancer cells, discuss how the biology and the multifaceted functions of CAFs contribute to cancer progression, and finally, pave the way for CAF-related antitumor therapies.

The establishment of CDK9/RNA PolII/H3K4me3/DNA methylation feedback promotes HOTAIR expression by RNA elongation enhancement in cancer.

Long non-coding RNA HOX Transcript Antisense RNA (HOTAIR) is overexpressed in multiple cancers with diverse genetic profiles. Importantly, since HOTAIR heavily contributes to cancer progression by promoting tumor growth and metastasis, HOTAIR becomes a potential target for cancer therapy. However, the underlying mechanism leading to HOTAIR deregulation is largely unexplored. Here, we performed a pan-cancer analysis using more than 4,200 samples and found that intragenic exon CpG island (Ex-CGI) was hypermethylated and was positively correlated to HOTAIR expression. Also, we revealed that Ex-CGI methylation promotes HOTAIR expression through enhancing the transcription elongation process. Furthermore, we linked up the aberrant intragenic tri-methylation on H3 at lysine 4 (H3K4me3) and Ex-CGI DNA methylation in promoting transcription elongation of HOTAIR. Targeting the oncogenic CDK7-CDK9-H3K4me3 axis downregulated HOTAIR expression and inhibited cell growth in many cancers. To our knowledge, this is the first time that a positive feedback loop that involved CDK9-mediated phosphorylation of RNA Polymerase II Serine 2 (RNA PolII Ser2), H3K4me3, and intragenic DNA methylation, which induced robust transcriptional elongation and heavily contributed to the upregulation of oncogenic lncRNA in cancer has been demonstrated. Targeting the oncogenic CDK7-CDK9-H3K4me3 axis could be a novel therapy in many cancers through inhibiting the HOTAIR expression.

Frozen Fat Grafts Maintain Vascular Endothelial Growth Factor Expression and Mediate Angiogenesis During Adipose-Derived Stem Cell Enrichment for Soft Tissue Augmentation.

BACKGROUND: Fresh fat grafts are commonly used in both esthetic and reconstructive surgeries, but the graft resorption rate varies. Cryopreservation of unused fat for later touch-up is one option to resolve this variation. In our previous studies, we found that fat cryopreservation may be a practical strategy for storing fat tissue. To explore the cryopreservation method, we evaluated the role of vascular endothelial growth factor (VEGF) in human frozen fat grafts. METHODS: The concentration of VEGF in human frozen fat grafts subjected to different preservation times was determined using Western blotting and enzyme-linked immunosorbent assay. The angiogenic effect of frozen fat grafts was evaluated using a chorioallantoic membrane assay. Furthermore, the impact of adding human adipose-derived stem cells (hADSCs) or different concentrations of avastin (bevacizumab) to frozen fat grafts on angiogenesis was assessed. The viability of frozen fat grafts with or without hADSCs was evaluated using a nude mouse implantation study. Explanted fat tissues were examined on days 1, 4, 7, 14, 28, and 90, and morphological and histological analyses, immunohistochemistry, and enzyme-linked immunosorbent assay (VEGF concentration) were carried out. RESULTS: No significant difference in VEGF concentration between fresh and frozen fat was observed with respect to preservation duration. In the chorioallantoic membrane assay, frozen fat grafts with hADSCs displayed significantly enhanced angiogenesis. Avastin was found to decrease angiogenesis in frozen fat grafts. However, in the nude mouse implantation study, frozen fat grafts displayed VEGF maintenance, with the highest concentration observed on day 7. Adding hADSCs to the graft further increased the VEGF concentration and CD31 expression. Fat graft viability was found to be higher in the frozen fat grafts containing hADSCs than in grafts without hADSCs. CONCLUSIONS: Human fat grafts can maintain VEGF expression under frozen conditions for at least 12 months. The addition of hADSCs to the frozen fat graft could further enhance angiogenesis, VEGF expression, and fat cell viability.