Gastrin-releasing peptide receptor antagonist RC-3095 inhibits Porphyromonas gingivalis lipopolysaccharide-accelerated atherosclerosis by suppressing inflammatory responses in endothelial cells and macrophages.

OBJECTIVE: Porphyromonas gingivalis (P. gingivalis), one of the major periodontopathogens, is associated with the progression and exacerbation of atherosclerosis. In this study, we aimed to investigate whether the gastrin-releasing peptide receptor antagonist, RC-3095, could attenuate P. gingivalis LPS-induced inflammatory responses in endothelial cells and macrophages, as well as atherosclerosis in an ApoE-/- mouse model treated with P. gingivalis LPS. METHODS: The effect of RC-3095 on P. gingivalis LPS-induced endothelial inflammation was examined using HUVECs and rat aortic endothelium. THP-1 cells were polarized into M1 macrophages by exposure to P. gingivalis LPS, with or without RC-3095. The effect of RC-3095 on atherosclerosis progression was assessed in high-fat-fed male ApoE-/- mice through injections of P. gingivalis LPS, RC-3095, or a combination of both. RESULTS: RC-3095 significantly reduced P. gingivalis LPS-induced leukocyte adhesion to endothelial cells and aortic endothelium by suppressing NF-κB-dependent expressions of ICAM-1 and VCAM-1. In addition, RC-3095 inhibited the P. gingivalis LPS-induced polarization of M1 macrophages by blocking the MAPK and NF-κB signaling pathways. Moreover, RC-3095 decreased the area of atherosclerotic lesions in ApoE-/- mice, which was accelerated by P. gingivalis LPS injection, and lowered the expressions of ICAM-1 and VCAM-1 in the aortic tissue of mice with atherosclerosis. CONCLUSIONS: RC-3095 can alleviate P. gingivalis LPS-induced endothelial inflammation, macrophage polarization, and atherosclerosis progression, suggesting its potential as a therapeutic approach for periodontal pathogen-associated atherosclerosis.

The role of spinal cord neuroanatomy and the variances of epidurally evoked spinal responses.

BACKGROUND: Spinal cord stimulation (SCS) has demonstrated multiple benefits in treating chronic pain and other clinical disorders related to sensorimotor dysfunctions. However, the underlying mechanisms are still not fully understood, including how electrode placement in relation to the spinal cord neuroanatomy influences epidural spinal recordings (ESRs). To characterize this relationship, this study utilized stimulation applied at various anatomical sections of the spinal column, including at levels of the intervertebral disc and regions correlating to the dorsal root entry zone. METHOD: Two electrode arrays were surgically implanted into the dorsal epidural space of the swine. The stimulation leads were positioned such that the caudal-most electrode contact was at the level of a thoracic intervertebral segment. Intraoperative cone beam computed tomography (CBCT) images were utilized to precisely determine the location of the epidural leads relative to the spinal column. High-resolution microCT imaging and 3D-model reconstructions of the explanted spinal cord illustrated precise positioning and dimensions of the epidural leads in relation to the surrounding neuroanatomy, including the spinal rootlets of the dorsal and ventral columns of the spinal cord. In a separate swine cohort, implanted epidural leads were used for SCS and recording evoked ESRs. RESULTS: Reconstructed 3D-models of the swine spinal cord with epidural lead implants demonstrated considerable distinctions in the dimensions of a single electrode contact on a standard industry epidural stimulation lead compared to dorsal rootlets at the dorsal root entry zone (DREZ). At the intervertebral segment, it was observed that a single electrode contact may cover 20-25% of the DREZ if positioned laterally. Electrode contacts were estimated to be ~0.75 mm from the margins of the DREZ when placed at the midline. Furthermore, ventral rootlets were observed to travel in proximity and parallel to dorsal rootlets at this level prior to separation into their respective sides of the spinal cord. Cathodic stimulation at the level of the intervertebral disc, compared to an 'off-disc' stimulation (7 mm rostral), demonstrated considerable variations in the features of recorded ESRs, such as amplitude and shape, and evoked unintended motor activation at lower stimulation thresholds. This substantial change may be due to the influence of nearby ventral roots. To further illustrate the influence of rootlet activation vs. dorsal column activation, the stimulation lead was displaced laterally at ~2.88 mm from the midline, resulting in variances in both evoked compound action potential (ECAP) components and electromyography (EMG) components in ESRs at lower stimulation thresholds. CONCLUSION: The results of this study suggest that the ECAP and EMG components of recorded ESRs can vary depending on small differences in the location of the stimulating electrodes within the spinal anatomy, such as at the level of the intervertebral segment. Furthermore, the effects of sub-centimeter lateral displacement of the stimulation lead from the midline, leading to significant changes in electrophysiological metrics. The results of this pilot study reveal the importance of the small displacement of the electrodes that can cause significant changes to evoked responses SCS. These results may provide further valuable insights into the underlying mechanisms and assist in optimizing future SCS-related applications.

Colorimetric Detection of Furfural with Enhanced Visible Absorption of Furfural-DNPH in Basic Conditions.

Furfural is an intermediary toxic aldehyde compound produced during heat-induced food processing and storage. Furfural is also formed by the degradation of cellulosic insulation in oil-immersed electric potential transformers, whose level is an important indicator of aging for replacement. In this study, we report a new means to detect the trace level of furfural in a colorimetric manner. Furfural is reacted with dinitrophenylhydrazine (DNPH) in acid solutions. The colorless furfural-DNPH compound turns orange-colored as the solution changes to basic. The delocalization of the π-electron in the DNPH-aldehyde derivatives at the basic condition causes the shift of the absorption peak from 318 to 470 nm, which renders the solution orange-colored. The color and absorbance are saturated in 20 min of incubation. There is high linearity between the absorbance and the concentration of furfural in the range of 0-0.2 mM, which enables the quantitative detection of furfural. The limit of detection is estimated to be as low as 1.76 µM for the absorbance analysis and 10 µM for the naked eyes. The colorimetric assay protocol is applicable to the detection of various aromatic aldehydes, which show strong π-electron delocalization and is not applicable to aliphatic aldehydes due to lack of delocalization. This simple assay can be conducted in typical 96-well microplates using a microplate reader, which provides a low-cost and high-throughput screening. Therefore, we believe that our method is potentially applicable for the quantitative detection of aromatic aldehydes in various samples from foods, electronic devices, and so on.

Hispidulin Inhibits the Vascular Inflammation Triggered by Porphyromonas gingivalis Lipopolysaccharide.

Hispidulin is a natural bioactive flavonoid that has been studied for its potential therapeutic properties, including its anti-inflammatory, antioxidant, and neuroprotective effects. The aim of this study was to explore whether hispidulin could inhibit the endothelial inflammation triggered by Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS). The adhesion of monocytes to the vascular endothelium was evaluated through in vitro and ex vivo monocyte adhesion assays. We analyzed the migration of monocytes across the endothelial layer using a transmigration assay. The results showed that treatment with hispidulin decreased the P. gingivalis LPS-induced adhesion of monocytes to endothelial cells and their migration by suppressing the P. gingivalis LPS-triggered expression of intercellular adhesion molecule-1 (ICAM-1) through downregulating nuclear factor-қB (NF-қB). In addition, hispidulin inhibited P. gingivalis LPS-induced mitogen-activated protein kinases (MAPKs) and AKT in endothelial cells. Altogether, the results indicate that hispidulin suppresses the vascular inflammation induced by P. gingivalis LPS. Mechanistically, it prevents the adhesion of monocytes to the vascular endothelium and migration and inhibits NF-қB, MAPKs, and AKT signaling in endothelial cells.

Modulation of Kex2p Cleavage Site for In Vitro Processing of Recombinant Proteins Produced by Saccharomyces cerevisiae.

Kex2 protease (Kex2p) is a membrane-bound serine protease responsible for the proteolytic maturation of various secretory proteins by cleaving after dibasic residues in the late Golgi network. In this study, we present an application of Kex2p as an alternative endoprotease for the in vitro processing of recombinant fusion proteins produced by the yeast Saccharomyces cerevisiae. The proteins were expressed with a fusion partner connected by a Kex2p cleavage sequence for enhanced expression and easy purification. To avoid in vivo processing of fusion proteins by Kex2p during secretion and to guarantee efficient removal of the fusion partners by in vitro Kex2p processing, P1', P2', P4, and P3 sites of Kex2p cleavage sites were elaborately manipulated. The general use of Kex2p in recombinant protein production was confirmed using several recombinant proteins.

Naringenin stimulates osteogenic/odontogenic differentiation and migration of human dental pulp stem cells.

Background/purpose: Naringenin, a naturally occurring flavanone in citrus fruits, regulates bone formation by bone marrow-derived mesenchymal stem cells. The purpose of this study was to characterize the effects of naringenin on some biological behaviors of human dental pulp stem cells (HDPSCs). Materials and methods: HDPSCs were cultured in osteogenic differentiation medium and osteo/odontogenic differentiation and mineralization were analyzed by alkaline phosphatase (ALP) staining and Alizarin Red S (ARS) staining. The migration of HDPSCs was evaluated by transwell chemotactic migration assays and scratch wound healing migration assay. Using tooth slice/scaffold model, we assessed the in vivo odontogenic differentiation potential of HDPSCs. Results: We have demonstrated that naringenin increases the osteogenic/odontogenic differentiation of HDPSCs through regulation of osteogenic-related proteins and the migratory ability of HDPSCs through stromal cell derived factor-1 (SDF-1)/C-X-C chemokine receptor type 4 (CXCR4) axis. Moreover, naringenin promotes the expression of dentin matrix acidic phosphoprotein-1 (DMP-1) and dentin sialophosphoprotein (DSPP) in HDPSCs seeded on tooth slice/scaffolds that are subcutaneously implanted into immunodeficient mice. Conclusion: Our present study suggests that naringenin promotes migration and osteogenic/odontogenic differentiation of HDPSCs and may serve as a promising candidate in dental tissue engineering and bone regeneration.

Characterization and applications of evoked responses during epidural electrical stimulation.

BACKGROUND: Epidural electrical stimulation (EES) of the spinal cord has been FDA approved and used therapeutically for decades. However, there is still not a clear understanding of the local neural substrates and consequently the mechanism of action responsible for the therapeutic effects. METHOD: Epidural spinal recordings (ESR) are collected from the electrodes placed in the epidural space. ESR contains multi-modality signal components such as the evoked neural response (due to tonic or BurstDR™ waveforms), evoked muscle response, stimulation artifact, and cardiac response. The tonic stimulation evoked compound action potential (ECAP) is one of the components in ESR and has been proposed recently to measure the accumulative local potentials from large populations of neuronal fibers during EES. RESULT: Here, we first review and investigate the referencing strategies, as they apply to ECAP component in ESR in the domestic swine animal model. We then examine how ECAP component can be used to sense lead migration, an adverse outcome following lead placement that can reduce therapeutic efficacy. Lastly, we show and isolate concurrent activation of local back and leg muscles during EES, demonstrating that the ESR obtained from the recording contacts contain both ECAP and EMG components. CONCLUSION: These findings may further guide the implementation of recording and reference contacts in an implantable EES system and provide preliminary evidence for the utility of ECAP component in ESR to detect lead migration. We expect these results to facilitate future development of EES methodology and implementation of use of different components in ESR to improve EES therapy.

Inhibition of the Semaphorin 4D-Plexin-B1 axis prevents calcification in vascular smooth muscle cells.

Vascular calcification is common in cardiovascular diseases including atherosclerosis, and is associated with an increased risk of pathological events and mortality. Some semaphorin family members play an important role in atherosclerosis. In the present study, we show that Semaphorin 4D/Sema4D and its Plexin-B1 receptor were significantly upregulated in calcified aorta of a rat chronic kidney disease model. Significantly higher Sema4D and Plexin-B1 expression was also observed during inorganic phosphate-induced calcification of vascular smooth muscle cells. Knockdown of Sema4D or Plexin-B1 genes attenuated both the phosphate-induced osteogenic phenotype of vascular smooth muscle cells, through regulation of SMAD1/5 signaling, as well as apoptosis of vascular smooth muscle cells, through modulation of the Gas6/Axl/Akt survival pathway. Taken together, our results offer new insights on the role of Sema4D and Plexin-B1 as potential therapeutic targets against vascular calcification. [BMB Reports 2023; 56(3): 160-165].

A new platform host for strong expression under GAL promoters without inducer in Saccharomyces cerevisiae.

The gal80 mutant of yeast Saccharomyces cerevisiae is used for the constitutive expression under strong GAL promoters without galactose induction. To enhance productivity of gal80 mutant, an alternative strain, allgal, was developed by removing all galactose-utilizing genes that consume significant cellular resources in the gal80 strain when cultured in non-galactose conditions. The efficacy of the allgal mutant (gal80, gal1, gal2, gal7, and gal10) was verified by assessing the secretory expression of three recombinant proteins, Candida antarctica lipase B (CalB), human serum albumin (HSA), and human epidermal growth factor (hEGF), using the GAL10 promoter. The growth of the allgal mutant was enhanced by 15-38% compared to the gal80 mutant, and the secretion of recombinant proteins also increased by 16-22% in fed-batch fermentation. Thus, the expression of recombinant proteins using GAL10 promoter in the allgal mutant is suitable for the economical production of recombinant proteins in S. cerevisiae.

Tonic, Burst, and Burst-Cycle Spinal Cord Stimulation Lead to Differential Brain Activation Patterns as Detected by Functional Magnetic Resonance Imaging.

OBJECTIVE: The objective of this preclinical study was to examine the responses of the brain to noxious stimulation in the presence and absence of different modes of spinal cord stimulation (SCS) using blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD-fMRI). MATERIALS AND METHODS: Sprague-Dawley rats were randomized to groups based on the mode of SCS delivered which included tonic stimulation (n = 27), burst stimulation (n = 30), and burst-cycle stimulation (n = 29). The control (sham) group (n = 28) received no SCS. The SCS electrode was inserted between T10 and T12 spinal levels prior to fMRI session. The experimental protocol for fMRI acquisition consisted of an initial noxious stimulation phase, a treatment phase wherein the SCS was turned on concurrently with noxious stimulation, and a residual effect phase wherein the noxious stimulation alone was turned on. The responses were statistically analyzed through paired t-test and the results were presented as z-scores for the quantitative analysis of the fMRI data. RESULTS: The treatment with different SCS modes attenuated the BOLD brain responses to noxious hindlimb stimulation. The tonic, burst, and burst-cycle SCS treatment attenuated BOLD responses in the caudate putamen (CPu), insula (In), and secondary somatosensory cortex (S2). There was little to no corresponding change in sham control in these three regions. The burst and burst-cycle SCS demonstrated greater attenuation of BOLD signals in CPu, In, and S2 compared to tonic stimulation. CONCLUSION: The high-resolution fMRI study using a rat model demonstrated the potential of different SCS modes to act on several pain-matrix-related regions of the brain in response to noxious stimulation. The burst and burst-cycle SCS exhibited greater brain activity reduction in response to noxious hindlimb stimulation in the caudate putamen, insula, and secondary somatosensory cortex compared to tonic stimulation.

Analgesic Effects of Tonic and Burst Dorsal Root Ganglion Stimulation in Rats With Painful Tibial Nerve Injury.

OBJECTIVES: Dorsal root ganglion (DRG) stimulation is effective in treating chronic pain. While burst stimulation has been proven to enhance the therapeutic efficacy in spinal cord stimulation, currently only a tonic stimulation waveform is clinically used in DRG stimulation. We hypothesized that burst DRG stimulation might also produce analgesic effect in a preclinical neuropathic pain model. We evaluated both the therapeutic effects of burst DRG stimulation and the possible effects of DRG stimulation upon inflammation within the DRG in a preclinical neuropathic pain model. MATERIALS AND METHODS: Rats received either a painful tibial nerve injury or sham surgery. Analgesic effects of DRG stimulation were evaluated by testing a battery of evoked pain-related behaviors as well as measuring the positive affective state associated with relief of spontaneous pain using conditioned place preference. Histological evidence for neuronal trauma or neuroinflammation was evaluated. RESULTS: All of the waveforms tested (20 Hz-tonic, 20 Hz-burst, and 40 Hz-burst) have similar analgesic effects in sensory tests and conditioned place preference. Long-term DRG stimulation for two weeks does not change DRG expression of markers for nerve injury and neuroinflammation. CONCLUSIONS: DRG stimulation using burst waveform might be also suitable for treating neuropathic pain.

Neuromedin B modulates phosphate-induced vascular calcification.

Vascular calcification is the heterotopic accumulation of calcium phosphate salts in the vascular tissue and is highly correlated with increased cardiovascular morbidity and mortality. In this study, we found that the expression of neuromedin B (NMB) and NMB receptor is upregulated in phosphate-induced calcification of vascular smooth muscle cells (VSMCs). Silencing of NMB or treatment with NMB receptor antagonist, PD168368, inhibited the phosphate-induced osteogenic differentiation of VSMCs by inhibiting Wnt/ß-catenin signaling and VSMC apoptosis. PD168368 also attenuated the arterial calcification in cultured aortic rings and in a rat model of chronic kidney disease. The results of this study suggest that NMB-NMB receptor axis may have potential therapeutic value in the diagnosis and treatment of vascular calcification. [BMB Reports 2021; 54(11): 569-574].

Multicentre, clinical trial of burst spinal cord stimulation for neck and upper limb pain NU-BURST: a trial protocol.

BACKGROUND: Spinal cord stimulation (SCS) is an established therapy for chronic neuropathic pain and most frequently utilised for Failed Back Surgery Syndrome (FBSS). BurstDR™ also known as DeRidder Burst-SCS, a novel waveform, has demonstrated superiority to conventional tonic stimulation of the thoracic spine in FBSS. There are case reports of an improvement in multidimensional pain outcomes using DeRidder Burst-SCS in the cervical spine for chronic neck and cervical radicular pain. The safety and efficacy of cervical DeRidder Burst-SCS stimulation still however remain undetermined. METHODS/DESIGN: This is a prospective, multicentre feasibility trial evaluating the safety and therapeutic efficacy of DeRidder Burst-SCS stimulation for the treatment of chronic intractable neck pain with or without radiation to the arm, shoulder, and upper back. After baseline evaluation, subjects will undergo an SCS trial using the Abbott Invisible Trial system according to standard clinical procedures. During the trial phase, SCS leads will be implanted in the cervical epidural space. At the end of the SCS trial, subjects experiencing at least 50% pain relief will be considered for permanent implant. Pain intensity, medication usage, and other multidimensional pain outcomes will be collected. The timing of these will be at baseline, end of the SCS trial and at 3-, 6-, and 12-month visits. Incidence of adverse events will be collected throughout the study duration. DISCUSSION: The results of this feasibility study will validate the efficacy and safety of DeRidder Burst-SCS stimulation in the cervical spine. The results obtained in this study will potentially be used to generate a level 1 evidence-based study with formal statistical hypotheses testing. TRIAL REGISTRATION: www.clinicaltrials.gov Identifier: NCT03159169.

The role of a suburban forest in controlling vertical trace gas and OH reactivity distributions - a case study for the Seoul metropolitan area.

We present trace gas vertical profiles observed by instruments on the NASA DC-8 and at a ground site during the Korea-US air quality study (KORUS) field campaign in May to June 2016. We focus on the region near the Seoul metropolitan area and its surroundings where both anthropogenic and natural emission sources play an important role in local photochemistry. Integrating ground and airborne observations is the major research goal of many atmospheric chemistry field campaigns. Although airborne platforms typically aim to sample from near surface to the free troposphere, it is difficult to fly very close to the surface especially in environments with complex terrain or a populated area. A detailed analysis integrating ground and airborne observations associated with specific concentration footprints indicates that reactive trace gases are quickly oxidized below an altitude of 700 m. The total OH reactivity profile has a rapid decay in the lower part of troposphere from surface to the lowest altitude (700 m) sampled by the NASA DC-8. The decay rate is close to that of very reactive biogenic volatile organic compounds such as monoterpenes. Therefore, we argue that photochemical processes in the bottom of the boundary layer, below the typical altitude of aircraft sampling, should be thoroughly investigated to properly assess ozone and secondary aerosol formation.

Infection of Porphyromonas gingivalis Increases Phosphate-Induced Calcification of Vascular Smooth Muscle Cells.

Accumulating evidence suggests a link between periodontal disease and cardiovascular diseases. Vascular calcification is the pathological precipitation of phosphate and calcium in the vasculature and is closely associated with increased cardiovascular risk and mortality. In this study, we have demonstrated that the infection with Porphyromonas gingivalis (P. gingivalis), one of the major periodontal pathogens, increases inorganic phosphate-induced vascular calcification through the phenotype transition, apoptosis, and matrix vesicle release of vascular smooth muscle cells. Moreover, P. gingivalis infection accelerated the phosphate-induced calcium deposition in cultured rat aorta ex vivo. Taken together, our findings indicate that P. gingivalis contributes to the periodontal infection-related vascular diseases associated with vascular calcification.

Semaphorin-3C Is Upregulated in Polycystic Kidney Epithelial Cells and Inhibits Angiogenesis of Glomerular Endothelial Cells.

BACKGROUND: Polycystic kidney disease (PKD) is a hereditary disease characterized by cyst formation in the kidneys bilaterally. It has been observed that semaphorin-3C (SEMA3C) is overexpressed in polycystic kidney epithelial cells. It is hypothesized that upregulated SEMA3C would contribute to survival of polycystic kidney epithelial cells. Furthermore, as the kidney is a highly vascularized organ, the secreted SEMA3C from PKD epithelial cells will affect glomerular endothelial cells (GECs) in a paracrine manner. METHODS: To evaluate the effect of SEMA3C on renal cells, siSEMA3C-treated PKD epithelial cells were used for further analysis, and GECs were exposed to recombinant SEMA3C (rSEMA3C). Also, co-culture and treatment of conditioned media were employed to confirm whether PKD epithelial cells could influence on GECs via SEMA3C secretion. RESULTS: SEMA3C knockdown reduced proliferation of PKD epithelial cells. In case of GECs, exposure to rSEMA3C decreased angiogenesis, which resulted from suppressed migratory ability not cell proliferation. CONCLUSIONS: This study indicates that SEMA3C is the aggravating factor in PKD. Thus, it is proposed that targeting SEMA3C can be effective to mitigate PKD.

Inhibition of Gastrin-Releasing Peptide Attenuates Phosphate-Induced Vascular Calcification.

Vascular calcification is the pathological deposition of calcium/phosphate in the vascular system and is closely associated with cardiovascular morbidity and mortality. Here, we investigated the role of gastrin-releasing peptide (GRP) in phosphate-induced vascular calcification and its potential regulatory mechanism. We found that the silencing of GRP gene and treatment with the GRP receptor antagonist, RC-3095, attenuated the inorganic phosphate-induced calcification of vascular smooth muscle cells (VSMCs). This attenuation was caused by inhibiting phenotype change, apoptosis and matrix vesicle release in VSMCs. Moreover, the treatment with RC-3095 effectively ameliorated phosphate-induced calcium deposition in rat aortas ex vivo and aortas of chronic kidney disease in mice in vivo. Therefore, the regulation of the GRP-GRP receptor axis may be a potential strategy for treatment of diseases associated with excessive vascular calcification.

Pentraxin-3 Modulates Osteogenic/Odontogenic Differentiation and Migration of Human Dental Pulp Stem Cells.

Pentraxin-3 (PTX3) is recognized as a modulator of inflammation and a mediator of tissue repair. In this study, we characterized the role of PTX3 on some biological functions of human dental pulp stem cells (HDPSCs). The expression level of PTX3 significantly increased during osteogenic/odontogenic differentiation of HDPSCs, whereas the knockdown of PTX3 decreased this differentiation. Silencing of PTX3 in HDPSCs inhibited their migration and C-X-C chemokine receptor type 4 (CXCR4) expression. Our present study indicates that PTX3 is involved in osteogenic/odontogenic differentiation and migration of HDPSCs, and may contribute to the therapeutic potential of HDPSCs for regeneration and repair.

Three-Dimensional Shapes and Cell Deformability of Rat Red Blood Cells during and after Asphyxial Cardiac Arrest.

Changes in microcirculation are believed to perform an important role after cardiac arrest. In particular, rheological changes in red blood cells (RBCs) have been observed during and after ischemic-reperfusion injury. Employing three-dimensional laser interferometric microscopy, we investigated three-dimensional shapes and deformability of RBCs during and after asphyxial cardiac arrest in rats at the individual cell level. Rat cardiac arrest was induced by asphyxia. Five rats were maintained for 7 min of no-flow time, and then, cardiopulmonary resuscitation (CPR) was started. Blood samples were obtained before cardiac arrest, during CPR, and 60 min after return of spontaneous circulation (ROSC). Quantitative phase imaging (QPI) techniques based on laser interferometry were used to measure the three-dimensional refractive index (RI) tomograms of the RBC, from which structural and biochemical properties were retrieved. Dynamic membrane fluctuations in the cell membrane were also quantitatively and sensitively measured in order to investigate cell deformability. Mean corpuscular hemoglobin, mean cell volume, mean corpuscular hemoglobin concentration, and red blood cell distribution width remained unchanged during CPR and after ROSC compared with those before cardiac arrest. QPI results revealed that RBC membrane fluctuations, sphericity, and surface area did not change significantly during CPR or after ROSC compared with initial values. In conclusion, no three-dimensional shapes and cell deformability changes in RBCs were detected.