Photonically active bowtie nanoassemblies with chirality continuum.

Chirality is a geometrical property described by continuous mathematical functions1-5. However, in chemical disciplines, chirality is often treated as a binary left or right characteristic of molecules rather than a continuity of chiral shapes. Although they are theoretically possible, a family of stable chemical structures with similar shapes and progressively tuneable chirality is yet unknown. Here we show that nanostructured microparticles with an anisotropic bowtie shape display chirality continuum and can be made with widely tuneable twist angle, pitch, width, thickness and length. The self-limited assembly of the bowties enables high synthetic reproducibility, size monodispersity and computational predictability of their geometries for different assembly conditions6. The bowtie nanoassemblies show several strong circular dichroism peaks originating from absorptive and scattering phenomena. Unlike classical chiral molecules, these particles show a continuum of chirality measures2 that correlate exponentially with the spectral positions of the circular dichroism peaks. Bowtie particles with variable polarization rotation were used to print photonically active metasurfaces with spectrally tuneable positive or negative polarization signatures for light detection and ranging (LIDAR) devices.

Noncanonical autophagy promotes the visual cycle.

Phagocytosis and degradation of photoreceptor outer segments (POS) by retinal pigment epithelium (RPE) is fundamental to vision. Autophagy is also responsible for bulk degradation of cellular components, but its role in POS degradation is not well understood. We report that the morning burst of RPE phagocytosis coincided with the enzymatic conversion of autophagy protein LC3 to its lipidated form. LC3 associated with single-membrane phagosomes containing engulfed POS in an Atg5-dependent manner that required Beclin1, but not the autophagy preinitiation complex. The importance of this process was verified in mice with Atg5-deficient RPE cells that showed evidence of disrupted lysosomal processing. These mice also exhibited decreased photoreceptor responses to light stimuli and decreased chromophore levels that were restored with exogenous retinoid supplementation. These results establish that the interplay of phagocytosis and autophagy within the RPE is required for both POS degradation and the maintenance of retinoid levels to support vision.

Chiral assemblies of pinwheel superlattices on substrates.

The unique topology and physics of chiral superlattices make their self-assembly from nanoparticles highly sought after yet challenging in regard to (meta)materials1-3. Here we show that tetrahedral gold nanoparticles can transform from a perovskite-like, low-density phase with corner-to-corner connections into pinwheel assemblies with corner-to-edge connections and denser packing. Whereas corner-sharing assemblies are achiral, pinwheel superlattices become strongly mirror asymmetric on solid substrates as demonstrated by chirality measures. Liquid-phase transmission electron microscopy and computational models show that van der Waals and electrostatic interactions between nanoparticles control thermodynamic equilibrium. Variable corner-to-edge connections among tetrahedra enable fine-tuning of chirality. The domains of the bilayer superlattices show strong chiroptical activity as identified by photon-induced near-field electron microscopy and finite-difference time-domain simulations. The simplicity and versatility of substrate-supported chiral superlattices facilitate the manufacture of metastructured coatings with unusual optical, mechanical and electronic characteristics.

Enantiomer-dependent immunological response to chiral nanoparticles.

Chirality is a unifying structural metric of biological and abiological forms of matter. Over the past decade, considerable clarity has been achieved in understanding the chemistry and physics of chiral inorganic nanoparticles1-4; however, little is known about their effects on complex biochemical networks5,6. Intermolecular interactions of biological molecules and inorganic nanoparticles show some commonalities7-9, but these structures differ in scale, in geometry and in the dynamics of chiral shapes, which can both impede and strengthen their mirror-asymmetric complexes. Here we show that achiral and left- and right-handed gold biomimetic nanoparticles show different in vitro and in vivo immune responses. We use irradiation with circularly polarized light (CPL) to synthesize nanoparticles with controllable nanometre-scale chirality and optical anisotropy factors (g-factors) of up to 0.4. We find that binding of nanoparticles to two proteins from the family of adhesion G-protein-coupled receptors (AGPCRs)-namely cluster-of-differentiation 97 (CD97) and epidermal-growth-factor-like-module receptor 1 (EMR1)-results in the opening of mechanosensitive potassium-efflux channels, the production of immune signalling complexes known as inflammasomes, and the maturation of mouse bone-marrow-derived dendritic cells. Both in vivo and in vitro immune responses depend monotonically on the g-factors of the nanoparticles, indicating that nanoscale chirality can be used to regulate the maturation of immune cells. Finally, left-handed nanoparticles show substantially higher (1,258-fold) efficiency compared with their right-handed counterparts as adjuvants for vaccination against the H9N2 influenza virus, opening a path to the use of nanoscale chirality in immunology.

Astrocytes phagocytose adult hippocampal synapses for circuit homeostasis.

In the adult hippocampus, synapses are constantly formed and eliminated1,2. However, the exact function of synapse elimination in the adult brain, and how it is regulated, are largely unknown. Here we show that astrocytic phagocytosis3 is important for maintaining proper hippocampal synaptic connectivity and plasticity. By using fluorescent phagocytosis reporters, we find that excitatory and inhibitory synapses are eliminated by glial phagocytosis in the CA1 region of the adult mouse hippocampus. Unexpectedly, we found that astrocytes have a major role in the neuronal activity-dependent elimination of excitatory synapses. Furthermore, mice in which astrocytes lack the phagocytic receptor MEGF10 show a reduction in the elimination of excitatory synapses; as a result, excessive but functionally impaired synapses accumulate. Finally, Megf10-knockout mice show defective long-term synaptic plasticity and impaired formation of hippocampal memories. Together, our data provide strong evidence that astrocytes eliminate unnecessary excitatory synaptic connections in the adult hippocampus through MEGF10, and that this astrocytic function is crucial for maintaining circuit connectivity and thereby supporting cognitive function.

Direct-write 3D printing of plasmonic nanohelicoids by circularly polarized light.

Chiral plasmonic surfaces with 3D "forests" from nanohelicoids should provide strong optical rotation due to alignment of helical axis with propagation vector of photons. However, such three-dimensional nanostructures also demand multi-step nanofabrication, which is incompatible with many substrates. Large-scale photonic patterns on polymeric and flexible substrates remain unattainable. Here, we demonstrate the substrate-tolerant direct-write printing and patterning of silver nanohelicoids with out-of-plane 3D orientation using circularly polarized light. Centimeter-scale chiral plasmonic surfaces can be produced within minutes using inexpensive medium-power lasers. The growth of nanohelicoids is driven by the symmetry-broken site-selective deposition and self-assembly of the silver nanoparticles (NPs). The ellipticity and wavelength of the incident photons control the local handedness and size of the printed nanohelicoids, which enables on-the-fly modulation of nanohelicoid chirality during direct writing and simple pathways to complex multifunctional metasurfaces. Processing simplicity, high polarization rotation, and fine spatial resolution of the light-driven printing of stand-up helicoids provide a rapid pathway to chiral plasmonic surfaces, accelerating the development of chiral photonics for health and information technologies.

Unidirectional cross-activation of GRPR by MOR1D uncouples itch and analgesia induced by opioids.

Spinal opioid-induced itch, a prevalent side effect of pain management, has been proposed to result from pain inhibition. We now report that the µ-opioid receptor (MOR) isoform MOR1D is essential for morphine-induced scratching (MIS), whereas the isoform MOR1 is required only for morphine-induced analgesia (MIA). MOR1D heterodimerizes with gastrin-releasing peptide receptor (GRPR) in the spinal cord, relaying itch information. We show that morphine triggers internalization of both GRPR and MOR1D, whereas GRP specifically triggers GRPR internalization and morphine-independent scratching. Providing potential insight into opioid-induced itch prevention, we demonstrate that molecular and pharmacologic inhibition of PLCß3 and IP3R3, downstream effectors of GRPR, specifically block MIS but not MIA. In addition, blocking MOR1D-GRPR association attenuates MIS but not MIA. Together, these data suggest that opioid-induced itch is an active process concomitant with but independent of opioid analgesia, occurring via the unidirectional cross-activation of GRPR signaling by MOR1D heterodimerization.

Tumoural activation of TLR3-SLIT2 axis in endothelium drives metastasis.

Blood vessels support tumours by providing nutrients and oxygen, while also acting as conduits for the dissemination of cancer1. Here we use mouse models of breast and lung cancer to investigate whether endothelial cells also have active 'instructive' roles in the dissemination of cancer. We purified genetically tagged endothelial ribosomes and their associated transcripts from highly and poorly metastatic tumours. Deep sequencing revealed that metastatic tumours induced expression of the axon-guidance gene Slit2 in endothelium, establishing differential expression between the endothelial (high Slit2 expression) and tumoural (low Slit2 expression) compartments. Endothelial-derived SLIT2 protein and its receptor ROBO1 promoted the migration of cancer cells towards endothelial cells and intravasation. Deleting endothelial Slit2 suppressed metastatic dissemination in mouse models of breast and lung cancer. Conversely, deletion of tumoural Slit2 enhanced metastatic progression. We identified double-stranded RNA derived from tumour cells as an upstream signal that induces expression of endothelial SLIT2 by acting on the RNA-sensing receptor TLR3. Accordingly, a set of endogenous retroviral element RNAs were upregulated in metastatic cells and detected extracellularly. Thus, cancer cells co-opt innate RNA sensing to induce a chemotactic signalling pathway in endothelium that drives intravasation and metastasis. These findings reveal that endothelial cells have a direct instructive role in driving metastatic dissemination, and demonstrate that a single gene (Slit2) can promote or suppress cancer progression depending on its cellular source.

A dual-action niclosamide-based prodrug that targets cancer stem cells and inhibits TNBC metastasis.

Chemotherapy typically destroys the tumor mass but rarely eradicates the cancer stem cells (CSCs) that can drive metastatic recurrence. A key current challenge is finding ways to eradicate CSCs and suppress their characteristics. Here, we report a prodrug, Nic-A, created by combining a carbonic anhydrase IX (CAIX) inhibitor, acetazolamide, with a signal transducer and transcriptional activator 3 (STAT3) inhibitor, niclosamide. Nic-A was designed to target triple-negative breast cancer (TNBC) CSCs and was found to inhibit both proliferating TNBC cells and CSCs via STAT3 dysregulation and suppression of CSC-like properties. Its use leads to a decrease in aldehyde dehydrogenase 1 activity, CD44high/CD24low stem-like subpopulations, and tumor spheroid-forming ability. TNBC xenograft tumors treated with Nic-A exhibited decreased angiogenesis and tumor growth, as well as decreased Ki-67 expression and increased apoptosis. In addition, distant metastases were suppressed in TNBC allografts derived from a CSC-enriched population. This study thus highlights a potential strategy for addressing CSC-based cancer recurrence.

Sex-specific differences in ectopic fat and metabolic characteristics of paediatric nonalcoholic fatty liver disease.

BACKGROUND/OBJECTIVES: Sex-specific differences in obesity-related metabolic characteristics of non-alcoholic fatty liver disease (NAFLD) have rarely been explored, particularly in children with biopsy-verified NAFLD. The influence of sex hormones on ectopic fat disposition may cause inter-sex differences in various metabolic factors. This study aimed to assess the sex-based differences in ectopic fat and metabolic characteristics in children with NAFLD. SUBJECT/METHODS: We enrolled 63 children with biopsy-verified NAFLD (48 boys; mean age, 12.9 ± 3.2 years; mean body mass index z-score [BMI-z], 2.49 ± 1.21). Ectopic fat in the liver and pancreas was quantified based on magnetic resonance imaging within 2 days of the liver biopsy. Laboratory tests, body composition, blood pressure, and anthropometric measurements were also assessed. RESULTS: Sex-based differences were neither observed in age, BMI-z, or total body fat percentage nor in the proportions of obesity, abdominal obesity, diabetes, dyslipidaemia, hypertension, or metabolic syndrome. Furthermore, liver enzyme levels, lipid profiles, and pancreatic fat did not differ between the sexes. However, boys had significantly higher fasting insulin (median 133.2 vs. 97.8 pmol/L; p = 0.039), fasting plasma glucose (median 5.30 vs. 4.83 mmol/L; p = 0.013), homeostasis model assessment of insulin resistance (median 5.4 vs. 3.6; p = 0.025), serum uric acid (404.1 ± 101.2 vs. 322.4 ± 87.1 µmol/L; p = 0.009), and liver fat (median 26.3% vs. 16.3%; p = 0.014). CONCLUSIONS: Male-predominant hepatic steatosis and insulin resistance caused by sex-specific ectopic fat accumulation may contribute to higher uric acid levels in boys than in girls with NAFLD.

Predictive cut-off values for the triglyceride-to-high-density lipoprotein cholesterol ratio to predict metabolic syndrome in the middle-aged Korean population.

BACKGROUND AND AIMS: The triglyceride-to-high density lipoprotein cholesterol (TG/HDL) ratio is associated with insulin resistance related diseases, including metabolic syndrome (MetS). However, specific TG/HDL values that can predict MetS have not been well identified. In this study, we analyzed both cross-sectional and longitudinal data from two national Korean datasets to obtain TG/HDL cut-off values that can identify MetS and predict its occurrence. METHODS AND RESULTS: To distinguish the presence and occurrence of MetS, the cut-off values were determined using the maximum F-score calculated through a logistic regression analysis. To predict new-onset MetS within 10 years, Cox proportional hazard models were used to consider the time of occurrence. The TG/HDL cut-off values of 3.97, 3.24, and 3.24 were optimal for identifying current MetS and predicting new-onset MetS within 10 years and five years, respectively, in Korean men. In Korean women, the optimal values for each task were 3.18, 2.38, and 2.26, respectively. CONCLUSIONS: We suggest the TG/HDL ratio as a potential candidate predictor for MetS. Therefore, we anticipate that future studies will apply individual lipid levels as well as their combinatory values to establish models that predict the prevalence and occurrence of MetS, diabetes, and cardiovascular disease.

Graph-theoretical chirality measure and chirality-property relations for chemical structures with multiscale mirror asymmetries.

Chirality is an essential geometric property unifying small molecules, biological macromolecules, inorganic nanomaterials, biological microparticles, and many other chemical structures. Numerous chirality measures have attempted to quantify this geometric property of mirror asymmetry and to correlate these measures with physical and chemical properties. However, their utility has been widely limited because these correlations have been largely notional. Furthermore, chirality measures also require prohibitively demanding computations, especially for chiral structures comprised of thousands of atoms. Acknowledging the fundamental problems with quantification of mirror asymmetry, including the ambiguity of sign-variable pseudoscalar chirality measures, we revisit this subject because of the significance of quantifying chirality for quantitative biomimetics and describing the chirality of nanoscale materials that display chirality continuum and scale-dependent mirror asymmetry. We apply the concept of torsion within the framework of differential geometry to the graph theoretical representation of chiral molecules and nanostructures to address some of the fundamental problems and practical limitations of other chirality measures. Chiral gold clusters and other chiral structures are used as models to elaborate a graph-theoretical chirality (GTC) measure, demonstrating its applicability to chiral materials with different degrees of chirality at different scales. For specific cases, we show that GTC provides an adequate description of both the sign and magnitude of mirror asymmetry. The direct correlations with macroscopic properties, such as chiroptical spectra, are enhanced by using the hybrid chirality measures combining parameters from discrete mathematics and physics. Taking molecular helices as an example, we established a direct relation between GTC and optical activity, indicating that this chirality measure can be applied to chiral metamaterials and complex chiral constructs.

Ebastine impairs metastatic spread in triple-negative breast cancer by targeting focal adhesion kinase.

We sought to investigate the utility of ebastine (EBA), a second-generation antihistamine with potent anti-metastatic properties, in the context of breast cancer stem cell (BCSC)-suppression in triple-negative breast cancer (TNBC). EBA binds to the tyrosine kinase domain of focal adhesion kinase (FAK), blocking phosphorylation at the Y397 and Y576/577 residues. FAK-mediated JAK2/STAT3 and MEK/ERK signaling was attenuated after EBA challenge in vitro and in vivo. EBA treatment induced apoptosis and a sharp decline in the expression of the BCSC markers ALDH1, CD44 and CD49f, suggesting that EBA targets BCSC-like cell populations while reducing tumor bulk. EBA administration significantly impeded BCSC-enriched tumor burden, angiogenesis and distant metastasis while reducing MMP-2/-9 levels in circulating blood in vivo. Our findings suggest that EBA may represent an effective therapeutic for the simultaneous targeting of JAK2/STAT3 and MEK/ERK for the treatment of molecularly heterogeneous TNBC with divergent profiles. Further investigation of EBA as an anti-metastatic agent for the treatment of TNBC is warranted.

The effects of long-pulsed alexandrite laser therapy on facial redness and skin microbiota compositions in rosacea: A prospective, multicentre, single-arm clinical trial.

BACKGROUND: Rosacea is a chronic skin disorder characterised by abnormal neurovasculature and inflammation in the central region of the face. The efficacy of pulsed-dye laser and intense pulsed light treatments for rosacea have been demonstrated in several clinical trials. However, there is currently no research on the efficacy of long-pulsed alexandrite laser (LPAL) therapy alone for rosacea-related facial redness and its effect on skin microbiota. AIM: To evaluate the efficacy of LPAL therapy on facial redness in rosacea and assess changes in skin microbiota composition. METHODS: Subjects with rosacea (n = 21, mean age: 39.2 ± 11.3 years) were recruited from two medical institutions and received monthly LPAL treatments (Clarity II™, Lutronic Corp.) for 3 months. At each visit, clinical photographs were taken, and erythema was measured using a spectrometer. At the initial and final visits, the Dermatology Life Quality Index (DLQI) and Skin Sensitivity Questionnaire (SSQ) were evaluated. Skin swabs were obtained at the initial and final visit, and facial microbiome composition was analysed using 16S rRNA amplicon sequencing. RESULTS: After three LPAL treatment sessions, the average facial erythema index, measured using Mexameter® decreased significantly from 360.0 ± 96.7 at baseline to 312.0 ± 94.5 at the final visit (p < .05). The DLQI and SSQ showed significant improvement of symptoms. Skin microbiome diversity and relative abundance were altered significantly, particularly in the genera Clostridium, Lawsonella, Bacteroides, and Lactobacillus. CONCLUSIONS: LPAL therapy alone showed favourable efficacy for the treatment of facial redness in rosacea, with some impacts on the skin microbiota composition.

Squamous Cell Carcinoma Arising From Epidermal Cyst: A Case Series of 9 Patients With a Literature Review.

ABSTRACT: Epidermal cysts are among the most common benign subcutaneous tumors. However, malignant transformation of benign epidermal cysts into squamous carcinomas has been reported. Owing to its low incidence rate, the clinical and pathological features of this condition are not well understood. This study aimed to analyze the clinical and pathological characteristics of the malignant transformation of epidermal cysts, which could suggest an appropriate treatment strategy. We conducted a retrospective study of 9 patients diagnosed with squamous cell carcinoma arising from epidermal cysts. All patients underwent surgical excision, and clinical information regarding patient demographics, tumor characteristics, treatment, and outcomes was analyzed. The average age at diagnosis was 57.3 years, with an average latency period of 15.4 years. Five patients had undergone prior cyst excision or drainage, with an average of 2.3 episodes of recurrence. Surgical excision was the primary treatment in all cases, and 2 patients with margin involvement at the final pathology underwent re-excision with additional resection margins. No recurrence was observed during the follow-up period. Four patients had immune dysregulation due to an underlying chronic kidney disease or cancer. Our study emphasizes the need for increased awareness of squamous cell carcinoma arising from epidermal cysts in patients with a history of cyst existence or recurrence, especially those with immune deficiencies. We expect these findings to contribute to early suspicion of malignant transformation and guide adequate clinical decision-making.

The Effect of Rho Kinase Inhibitors on In Vitro Human Orbital Preadipocytes.

PURPOSE: To identify the effects of Rho Kinase (ROCK) inhibitor medications on human orbital adipogenesis, fibroblast proliferation, and fibrosis. METHODS: Orbital adipose tissue was obtained from patients with Graves' ophthalmopathy (GO) as well as controls (non-GO or normal) after informed consent was done. These tissue samples were cultured and adipogenesis was initiated. Levels of Rho Kinase as well as cellular mediators of orbital inflammation and fibrosis. The same cultures and measurements were then repeated with the use of a ROCK inhibitor (KD025-ROCK2) to assess for changes in adipogenesis as well as markers associated with inflammation and fibrosis. RESULTS: Rho Kinase levels in GO tissue were more highly expressed than in controls. These levels were suppressed with the use of the ROCK inhibitor KD025. There was a dose-dependent reduction in differentiation of orbital adipocytes with the use of KD025. KD025 reduced the levels of fibrosis-related gene expression. Finally, there was a significant reduction of transforming growth factor beta mediated phosphorylation signaling pathways in the KD025-treated GO tissue. CONCLUSION: This study shows that the ROCK inhibitor, KD025, helps to reduce the expression of ROCK in GO tissue along with reducing orbital adipocyte differentiation as well as cell mediators involved in fibrosis that occurs in GO.

Thickness of melanocytes in giant congenital melanocytic nevus for complete surgical excision: clinicopathological evaluation of 117 lesions according to the area and size.

BACKGROUND: Giant congenital melanocytic nevi (GCMN) are usually defined as nevi that exceed 20 cm in maximal diameter or 15% of the total body surface area. There have been reports of life-long malignant change risks arising from GCMN, leading to surgical excision of GCMN. This study aims to evaluate the thickness of melanocytes based on clinical factors in order to provide objective information for the complete resection of the lesion. METHODS: Overall, 75 patients diagnosed with GCMN between 2000 and 2021 were included, and their clinical records were collected retrospectively. 117 pathologic slides obtained during excision were reviewed to measure nevus thickness. Clinical factors were assessed with a generalized estimated equation model for association with nevus thickness. RESULTS: The thickness of nevus was significantly associated with the location and size. Nevus thickness was more superficial in the distal extremity than in the head and trunk (P = 0.003 [head]; P < 0.001 [trunk]; P = 0.091 [Proximal extremity]). Nevi sized 60 cm or more were significantly deeper than those measuring 20-29.9 cm (P = 0.035). An interaction between size and location existed (P < 0.001). Trunk and distal extremity lesions consistently exhibited uniform thickness regardless of lesion size, whereas head and proximal extremity lesions showed variations in thickness based on lesion size. CONCLUSION: GCMNs have differences in thickness according to location and size. Therefore, it is necessary to devise an approach optimized for each patient to treat GCMN. In the study, it was emphasized that the thickness of GCMN is correlated with clinical factors, specifically the location and size of the nevus. Consequently, these findings underscore the need for individualized treatment plans for effective surgical intervention.

Radiopharmaceuticals for Skeletal Muscle PET Imaging.

The skeletal muscles account for approximately 40% of the body weight and are crucial in movement, nutrient absorption, and energy metabolism. Muscle loss and decline in function cause a decrease in the quality of life of patients and the elderly, leading to complications that require early diagnosis. Positron emission tomography/computed tomography (PET/CT) offers non-invasive, high-resolution visualization of tissues. It has emerged as a promising alternative to invasive diagnostic methods and is attracting attention as a tool for assessing muscle function and imaging muscle diseases. Effective imaging of muscle function and pathology relies on appropriate radiopharmaceuticals that target key aspects of muscle metabolism, such as glucose uptake, adenosine triphosphate (ATP) production, and the oxidation of fat and carbohydrates. In this review, we describe how [18F]fluoro-2-deoxy-D-glucose ([18F]FDG), [18F]fluorocholine ([18F]FCH), [11C]acetate, and [15O]water ([15O]H2O) are suitable radiopharmaceuticals for diagnostic imaging of skeletal muscles.

Development and Evaluation of a Post-Traumatic Growth Program for Teachers Victimized by Students or Parents in South Korea: A Quasi-Experimental Study.

This quasi-experimental, nonequivalent control group study developed an eight-session post-traumatic growth program for teachers who had experienced violence from students and/or parents and examined its effects on rumination, burnout, and post-traumatic growth. A convenience sample was recruited from 11 elementary schools in Jeonbuk province, South Korea. The experimental group (n = 27) participated in bi-weekly sessions over four weeks, whereas the control group (n = 27) read educational materials on post-traumatic growth during the same period. The experimental group exhibited significantly greater decreases in intrusive rumination and higher post-traumatic growth than the control group. The program could be an effective intervention to assist traumatized teachers.

Effect of Remimazolam- versus Propofol-Based Total Intravenous General Anesthesia on Intraoperative Hemodynamic Stability for Major Spine Surgery in the Prone Position: A Randomized Controlled Trial.

Background and Objectives: Remimazolam offers advantages over propofol in terms of hemodynamic stability. However, it remains unclear whether remimazolam-based total intravenous anesthesia (TIVA) can reduce intraoperative hypotension compared to propofol-based TIVA, especially after prone positioning. In this study, we compared the effects of remimazolam- and propofol-based TIVA on intraoperative hemodynamic stability in patients undergoing surgery in the prone position. Materials and Methods: This study randomly assigned patients undergoing major spinal surgery in the prone position to the propofol or remimazolam group. Target-controlled infusion (2-3.5 µg/mL for induction and 2-3 µg/mL for maintenance) was used in the propofol group and continuous infusion (6 mg/kg/h for induction and 1-2 mg/kg/h for maintenance) was used in the remimazolam group; target-controlled infusion (3-5 ng/mL) of remifentanil was performed in both groups. The primary outcomes were the incidence of hypotensive episodes during the first hour after prone positioning. The secondary outcomes included the incidence of severe hypotension and the total amount of inotropic or vasopressor medication. Systolic and mean arterial pressure, heart rate, cardiac index and output, stroke volume, stroke volume variation, and pleth variability index were also evaluated. These variables were recorded per minute for the first 10 min after prone positioning, and every 10 min thereafter. Results: The study enrolled 94 patients (47 patients in each group). The incidence of hypotension or severe hypotension did not differ significantly between the two groups during the first hour after prone positioning. The total amount of ephedrine administered during the first hour after prone positioning was lesser (p = 0.020) and the mean arterial pressure during the initial 10 min after prone positioning was higher in the remimazolam group (p = 0.003). Conclusions: Our study uncovered no significant differences in the incidence of hypotension between remimazolam- and propofol-based TIVA in patients undergoing major spine surgery in prone position.