[Treatment of cervical ossification of posterior longitudinal ligament with titanium alloy trabecular bone three-dimensional printed artificial vertebral body].

Objective: To evaluate the effectiveness of using titanium alloy trabecular bone three-dimensional (3D) printed artificial vertebral body in treating cervical ossification of the posterior longitudinal ligament (OPLL). Methods: A retrospective analysis was conducted on clinical data from 45 patients with cervical OPLL admitted between September 2019 and August 2021 and meeting the selection criteria. All patients underwent anterior cervical corpectomy and decompression, interbody bone graft fusion, and titanium plate internal fixation. During operation, 21 patients in the study group received titanium alloy trabecular bone 3D printed artificial vertebral bodies, while 24 patients in the control group received titanium cages. There was no significant difference in baseline data such as gender, age, disease duration, affected segments, or preoperative pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), vertebral height, and C 2-7Cobb angle ( P>0.05). Operation time, intraoperative blood loss, and occurrence of complications were recorded for both groups. Preoperatively and at 3 and 12 months postoperatively, the functionality and symptom relief were assessed using JOA scores, VAS scores, and NDI evaluations. The vertebral height and C 2-7 Cobb angle were detected by imaging examinations and the implant subsidence and intervertebral fusion were observed. Results: The operation time and incidence of complications were significantly lower in the study group than in the control group ( P<0.05), while the difference in intraoperative blood loss between the two groups was not significant ( P>0.05). All patients were followed up 12-18 months, with the follow-up time of (14.28±4.34) months in the study group and (15.23±3.54) months in the control group, showing no significant difference ( t=0.809, P=0.423). The JOA score, VAS score, and NDI of the two groups improved after operation, and further improved at 12 months compared to 3 months, with significant differences ( P<0.05). At each time point, the study group exhibited significantly higher JOA scores and improvement rate compared to the control group ( P<0.05); but there was no significantly difference in VAS score and NDI between the two groups ( P>0.05). Imaging re-examination showed that the vertebral height and C 2-7Cobb angle of the two groups significantly increased at 3 and 12 months after operation ( P<0.05), and there was no significant difference between 3 and 12 months after operation ( P>0.05). At each time point, the vertebral height and C 2-7Cobb angle of the study group were significantly higher than those of the control group ( P<0.05), and the implant subsidence rate was significantly lower than that of the control group ( P<0.05). However, there was no significant difference in intervertebral fusion rate between the two groups ( P>0.05). Conclusion: Compared to traditional titanium cages, the use of titanium alloy trabecular bone 3D-printed artificial vertebral bodies for treating cervical OPLL results in shorter operative time, fewer postoperative complications, and lower implant subsidence rates, making it superior in vertebral reconstruction.

PARP1 Is Upregulated by Hyperglycemia Via N6-methyladenosine Modification and Promotes Diabetic Retinopathy.

Poly (ADP-ribose) polymerase 1 (PARP1) plays an irreplaceable role in the progression of diabetic retinopathy (DR). The m6A methylation in mRNA controls gene expression under various physiological and pathological conditions. However, effects of m6A methylation on PARP1 expression and DR progression at molecular level have not been documented. This study shows that the levels of PARP1, inflammatory factors, and fibrosis markers were significantly upregulated via evaluation by real-time PCR, western blotting, and immunofluorescence in both in vivo and in vitro experiments. EdU, CCK8, and apoptosis assays demonstrate that knockdown of PARP1 not only significantly improved the vitality of hRMECs (human retinal microvascular endothelial cells) even under high glucose conditions but also prevented glucose-induced inflammation, fibrosis, and angiogenesis in vivo. Mechanistically, dot blot, RNA pull-down, and immunoblots were implemented to explore the mechanism of m6A-mediated PARP1 stability and function. PARP1 is identified as a target of YTHDF2-mediated m6A modification. Overexpression of YTHDF2 substantially suppressed PARP1 mRNA m6A modification and inhibited its mRNA expression. Collectively, it has been demonstrated that PARP1 is frequently upregulated in human retinas and contributes to DR progression, and that YTHDF2-mediated m6A modification epigenetically regulates diabetes-induced PARP1 expression. Findings from this work may engender therapeutic targets for treating diabetic retinopathy.

Directed transforming of coke to active intermediates in methanol-to-olefins catalyst to boost light olefins selectivity.

Methanol-to-olefins (MTO), the most important catalytic process producing ethylene and propylene from non-oil feedstocks (coal, natural gas, biomass, CO2, etc.), is hindered by rapid catalyst deactivation due to coke deposition. Common practice to recover catalyst activity, i.e. removing coke via air combustion or steam gasification, unavoidably eliminates the active hydrocarbon pool species (HCPs) favoring light olefins formation. Density functional theory calculations and structured illumination microscopy reveal that naphthalenic cations, active HCPs enhancing ethylene production, are highly stable within SAPO-34 zeolites at high temperature. Here, we demonstrate a strategy of directly transforming coke to naphthalenic species in SAPO-34 zeolites via steam cracking. Fluidized bed reactor-regenerator pilot experiments show that an unexpectedly high light olefins selectivity of 85% is achieved in MTO reaction with 88% valuable CO and H2 and negligible CO2 as byproducts from regeneration under industrial-alike continuous operations. This strategy significantly boosts the economics and sustainability of MTO process.

Restoration of Hydrogen Sulfide Production in Diabetic Mice Improves Reparative Function of Bone Marrow Cells.

BACKGROUND: Bone marrow cell (BMC)-based treatment for critical limb ischemia in diabetic patients yielded a modest therapeutic effect resulting from cell dysfunction. Therefore, approaches that improve diabetic stem/progenitor cell functions may provide therapeutic benefits. Here, we tested the hypothesis that restoration of hydrogen sulfide (H2S) production in diabetic BMCs improves their reparative capacities. METHODS: Mouse BMCs were isolated by density-gradient centrifugation. Unilateral hind limb ischemia was conducted in 12- to 14-week-old db/+ and db/db mice by ligation of the left femoral artery. The H2S level was measured by either gas chromatography or staining with florescent dye sulfidefluor 7 AM. RESULTS: Both H2S production and cystathionine γ-lyase (CSE), an H2S enzyme, levels were significantly decreased in BMCs from diabetic db/db mice. Administration of H2S donor diallyl trisulfide (DATS) or overexpression of CSE restored H2S production and enhanced cell survival and migratory capacity in high glucose (HG)-treated BMCs. Immediately after hind limb ischemia surgery, the db/+ and db/db mice were administered DATS orally and/or given a local intramuscular injection of green fluorescent protein-labeled BMCs or red fluorescent protein-CSE-overexpressing BMCs (CSE-BMCs). Mice with hind limb ischemia were divided into 6 groups: db/+, db/db, db/db+BMCs, db/db+DATS, db/db+DATS+BMCs, and db/db+CSE-BMCs. DATS and CSE overexpression greatly enhanced diabetic BMC retention in ischemic hind limbs followed by improved blood perfusion, capillary/arteriole density, skeletal muscle architecture, and cell survival and decreased perivascular CD68+ cell infiltration in the ischemic hind limbs of diabetic mice. It is interesting to note that DATS or CSE overexpression rescued high glucose-impaired migration, tube formation, and survival of BMCs or mature human cardiac microvascular endothelial cells. Moreover, DATS restored nitric oxide production and decreased endothelial nitric oxide synthase phosphorylation at threonine 495 levels in human cardiac microvascular endothelial cells and improved BMC angiogenic activity under high glucose condition. Last, silencing CSE by siRNA significantly increased endothelial nitric oxide synthase phosphorylation at threonine 495 levels in human cardiac microvascular endothelial cells. CONCLUSIONS: Decreased CSE-mediated H2S bioavailability is an underlying source of BMC dysfunction in diabetes mellitus. Our data indicate that H2S and overexpression of CSE in diabetic BMCs may rescue their dysfunction and open novel avenues for cell-based therapeutics of critical limb ischemia in diabetic patients.

Cardiomyocyte-specific deletion of Gsk3α mitigates post-myocardial infarction remodeling, contractile dysfunction, and heart failure.

BACKGROUND: Injury due to myocardial infarction (MI) is largely irreversible. Once an infarct has occurred, the clinical goal becomes limiting remodeling, preserving left ventricular function, and preventing heart failure. Although traditional approaches (e.g., ß-blockers) partially preserve left ventricular function, novel strategies are needed to limit ventricular remodeling post-MI. OBJECTIVES: The aim of this study was to determine the role of glycogen synthase kinase-3α (GSK-3α) in post-MI remodeling. METHODS: Mice with cardiomyocyte-specific conditional deletion of Gsk3α and littermate controls underwent sham or MI surgery. Heart function was assessed using serial M-mode echocardiography. RESULTS: Gsk3α deletion in the heart markedly limits remodeling and preserves left ventricular function post-MI. This is due at least in part to dramatic thinning and expansion of the scar in the control hearts, which was less in the heart of knockout (KO) mice. In contrast, the border zone in the KO mice demonstrated a much thicker scar, and there were more viable cardiomyocytes within the scar/border zone. This was associated with less apoptosis and more proliferation of cardiomyocytes in the KO mice. Mechanistically, reduced apoptosis was due, at least in part, to a marked decrease in the Bax/Bcl-2 ratio, and increased cardiomyocyte proliferation was mediated through cyclin E1 and E2F-1 in the hearts of the KO mice. CONCLUSIONS: Taken together, these findings show that reducing GSK-3α expression in cardiomyocytes limits ventricular remodeling and preserves cardiac function post-MI. Specifically targeting GSK-3α could be a novel strategy to limit adverse remodeling and heart failure.

Upregulation of gamma-catenin compensates for the loss of beta-catenin in adult cardiomyocytes.

Recent progresses in signal transduction have revealed that beta-catenin signaling controls embryonic development, tumorigenesis, cell shape, and polarity. The role of this pathway in myocyte shape regulation during cardiac hypertrophy and failure is, however, not clearly defined. Since homozygous knockout of beta-catenin is embryonically lethal, we have deleted beta-catenin genes specifically in the heart of adult mice by crossing loxP-flanked beta-catenin mice with transgenic mice expressing tamoxifen-activated MerCreMer protein (MCM) driven by the alpha-myosin heavy chain promoter. Administration of tamoxifen to homozygous loxP-flanked beta-catenin mice positive for MCM induces the deletion of beta-catenin only in cardiomyocytes. Immunolabeling with beta-catenin antibody demonstrates that 90% of cardiomyocytes completely lose their beta-catenin expression but maintain normal rod-shaped morphology. The intercalated disk of cardiomyocytes lacking beta-catenin is morphologically unremarkable with normal distribution of vinculin, N-cadherin, desmoplakin, ZO-1, connexin43, and alpha-, gamma-, and p120 catenins. The expression level of these proteins, except that of gamma-catenin, is also similar in tamoxifen-treated and control mice with both homozygous loxP-flanked beta-catenin genes and the MCM transgene. Western blot analyses reveal that gamma-catenin increases in the heart of beta-catenin knockout mice compared with controls. Confocal microscopy also demonstrates that gamma-catenin has significantly increased in the intercalated disk of cardiomyocytes lacking beta-catenin. Echocardiographic data indicate that the knockout mice maintain normal ventricular geometry and cardiac function. The results suggest that upregulation of gamma-catenin can compensate for the loss of beta-catenin in cardiomyocytes to maintain normal cardiac structure and function.