Bridging Pico-to-Nanonewtons with a Ratiometric Force Probe for Monitoring Nanoscale Polymer Physics Before Damage

Understanding the transmission of nanoscale forces in the pico-to-nanonewton range is important in polymer physics. While physical approaches have limitations in analyzing the local force distribution in condensed environments, chemical analysis using force probes is promising. However, there are stringent requirements for probing the local forces generated before structural damage. The magnitude of those forces corresponds to the range below covalent bond scission (from 200 pN to several nN) and above thermal fluctuation (several pN). Here, we report a conformationally flexible dual-fluorescence force probe with a theoretically estimated threshold of approximately 100 pN. This probe enables ratiometric analysis of the distribution of local forces in a stretched polymer chain network. Without changing the intrinsic properties of the polymer, the force distribution was reversibly monitored in real time. Chemical control of the probe location demonstrated that the local stress concentration is twice as biased at crosslinkers than at main chains, particularly in a strain-hardening region. Due to the high sensitivity, the percentage of stressed force probes was estimated to be more than 1000 times higher than the activation rate of a conventional mechanophore.Comment: 21 pages and 5 figures in the main text, and 73 pages and 68 figures in the supplementary material

Bridging pico-to-nanonewtons with a ratiometric force probe for monitoring nanoscale polymer physics before damage

ピンと張られた分子鎖を定量する「羽ばたき型蛍光Force Probe」の開発 --高分子材料の中で力のかかった分子鎖の比率を蛍光イメージングで計測する--. 京都大学プレスリリース. 2022-01-14.Understanding the transmission of nanoscale forces in the pico-to-nanonewton range is important in polymer physics. While physical approaches have limitations in analyzing the local force distribution in condensed environments, chemical analysis using force probes is promising. However, there are stringent requirements for probing the local forces generated before structural damage. The magnitude of those forces corresponds to the range below covalent bond scission (from 200 pN to several nN) and above thermal fluctuation (several pN). Here, we report a conformationally flexible dual-fluorescence force probe with a theoretically estimated threshold of approximately 100 pN. This probe enables ratiometric analysis of the distribution of local forces in a stretched polymer chain network. Without changing the intrinsic properties of the polymer, the force distribution was reversibly monitored in real time. Chemical control of the probe location demonstrated that the local stress concentration is twice as biased at crosslinkers than at main chains, particularly in a strain-hardening region. Due to the high sensitivity, the percentage of the stressed force probes was estimated to be more than 1000 times higher than the activation rate of a conventional mechanophore

Association between KIR-HLA combination and ulcerative colitis and Crohn's disease in a Japanese population

ArticlePloS One. 13(4) :e0195778(2018)journal articl

Impact of cardiac support device combined with slow-release prostacyclin agonist in a canine ischemic cardiomyopathy model

BackgroundThe cardiac support device supports the heart and mechanically reduces left ventricular (LV) diastolic wall stress. Although it has been shown to halt LV remodeling in dilated cardiomyopathy, its therapeutic efficacy is limited by its lack of biological effects. In contrast, the slow-release synthetic prostacyclin agonist ONO-1301 enhances reversal of LV remodeling through biological mechanisms such as angiogenesis and attenuation of fibrosis. We therefore hypothesized that ONO-1301 plus a cardiac support device might be beneficial for the treatment of ischemic cardiomyopathy.MethodsTwenty-four dogs with induced anterior wall infarction were assigned randomly to 1 of 4 groups at 1 week postinfarction as follows: cardiac support device alone, cardiac support device plus ONO-1301 (hybrid therapy), ONO-1301 alone, or sham control.ResultsAt 8 weeks post-infarction, LV wall stress was reduced significantly in the hybrid therapy group compared with the other groups. Myocardial blood flow, measured by positron emission tomography, and vascular density were significantly higher in the hybrid therapy group compared with the cardiac support device alone and sham groups. The hybrid therapy group also showed the least interstitial fibrosis, the greatest recovery of LV systolic and diastolic functions, assessed by multidetector computed tomography and cardiac catheterization, and the lowest plasma N-terminal pro-B-type natriuretic peptide levels (P < .05).ConclusionsThe combination of a cardiac support device and the prostacyclin agonist ONO-1301 elicited a greater reversal of LV remodeling than either treatment alone, suggesting the potential of this hybrid therapy for the clinical treatment of ischemia-induced heart failure

Skeletal myoblast sheet transplantation improves the diastolic function of a pressure-overloaded right heart

ObjectiveThe development of right ventricular dysfunction has become a common problem after surgical repair of complex congenital heart disease. A recent study reported that tissue-engineered skeletal myoblast sheet transplantation improves left ventricular function in patients with dilated and ischemic cardiomyopathy. Therefore myoblast sheet transplantation might also improve ventricular performance in a rat model of a pressure-overloaded right ventricle.MethodsSeven-week-old male Lewis rats underwent pulmonary artery banding. Four weeks after pulmonary artery banding, myoblast sheet transplantation to the right ventricle was performed in the myoblast sheet transplantation group (n = 20), whereas a sham operation was performed in the sham group (n = 20).ResultsFour weeks after performing the procedure, a hemodynamic assessment with a pressure–volume loop showed a compensatory increase in systolic function in both groups. However, only the myoblast sheet transplantation group showed a significant improvement in the diastolic function: end-diastolic pressure (sham vs myoblast sheet transplantation, 10.3 ± 3.1 vs 5.0 ± 3.7 mm Hg; P < .001), time constant of isovolumic relaxation (11.1 ± 2.5 vs 7.6 ± 1.2 ms, P < .001), and end-diastolic pressure–volume relationship (16.1 ± 4.5 vs 7.6 ± 2.4/mL, P < .005). The right ventricular weight and cell size similarly increased in both groups. A histologic assessment demonstrated significantly suppressed ventricular fibrosis and increased capillary density in the myoblast sheet transplantation group in comparison with those in the sham group. Reverse transcription–polymerase chain reaction demonstrated an increased myocardial gene expression of hepatocyte growth factor and vascular endothelial growth factor in the myoblast sheet transplantation group but not in the sham group.ConclusionsSkeletal myoblast sheet transplantation improved the diastolic dysfunction and suppressed ventricular fibrosis with increased capillary density in a rat model of a pressure-overloaded right ventricle. This method might become a novel strategy for the myocardial regeneration of right ventricular failure in patients with congenital heart disease

Correlation analysis between gut microbiota alterations and the cytokine response in patients with coronavirus disease during hospitalization

The role of the intestinal microbiota in coronavirus disease 2019 (COVID-19) is being elucidated. Here, we analyzed the temporal changes in microbiota composition and the correlation between inflammation biomarkers/cytokines and microbiota in hospitalized COVID-19 patients. We obtained stool specimens, blood samples, and patient records from 22 hospitalized COVID-19 patients and performed 16S rRNA metagenomic analysis of stool samples over the course of disease onset compared to 40 healthy individual stool samples. We analyzed the correlation between the changes in the gut microbiota and plasma proinflammatory cytokine levels. Immediately after admission, differences in the gut microbiota were observed between COVID-19 patients and healthy subjects, mainly including enrichment of the classes Bacilli and Coriobacteriia and decrease in abundance of the class Clostridia. The bacterial profile continued to change throughout the hospitalization, with a decrease in short-chain fatty acid-producing bacteria including Faecalibacterium and an increase in the facultatively anaerobic bacteria Escherichia-Shigella. A consistent increase in Eggerthella belonging to the class Coriobacteriia was observed. The abundance of the class Clostridia was inversely correlated with interferon-γ level and that of the phylum Actinobacteria, which was enriched in COVID-19, and was positively correlated with gp130/sIL-6Rb levels. Dysbiosis was continued even after 21 days from onset. The intestines tended to be an aerobic environment in hospitalized COVID-19 patients. Because the composition of the gut microbiota correlates with the levels of proinflammatory cytokines, this finding emphasizes the need to understand how pathology is related to the temporal changes in the specific gut microbiota observed in COVID-19 patients. IMPORTANCE There is growing evidence that the commensal microbiota of the gastrointestinal and respiratory tracts regulates local and systemic inflammation (gut-lung axis). COVID-19 is primarily a respiratory disease, but the involvement of microbiota changes in the pathogenesis of this disease remains unclear. The composition of the gut microbiota of patients with COVID-19 changed over time during hospitalization, and the intestines tended to be an aerobic environment in hospitalized COVID-19 patients. These changes in gut microbiota may induce increased intestinal permeability, called leaky gut, allowing bacteria and toxins to enter the circulatory system and further aggravate the systemic inflammatory response. Since gut microbiota composition correlates with levels of proinflammatory cytokines, this finding highlights the need to understand how pathology relates to the gut environment, including the temporal changes in specific gut microbiota observed in COVID-19 patients

A self-renewing, tissue-engineered vascular graft for arterial reconstruction

ObjectiveVarious tissue-engineered vascular grafts have been studied to overcome the clinical disadvantages of conventional prostheses. Previous tissue-engineered vascular grafts have generally required preoperative cellular manipulation or use of bioreactors to improve performance, and their mechanical properties have been insufficient. We focused on the concept of in situ cellularization and developed a tissue-engineered vascular graft for arterial reconstruction that would facilitate renewal of autologous tissue without any pretreatment.MethodsThe graft comprised an interior of knitted polyglycolic acid compounded with collagen to supply a scaffold for tissue growth and an exterior of woven poly-l-lactic acid for reinforcement. All components were biocompatible and biodegradable, with excellent cellular affinity. The grafts, measuring 10 mm in internal diameter and 30 mm in length, were implanted into porcine aortas, and their utility was evaluated to 12 months after grafting.ResultsAll explants were patent throughout the observation period, with no sign of thrombus formation or aneurysmal change. Presence in the neomedia of endothelialization with proper integrity and parallel accumulation of functioning smooth muscle cells, which responded to vasoreactive agents, was confirmed in an early phase after implantation. Sufficient collagen synthesis and lack of elastin were quantitatively demonstrated. Dynamic assessment and long-term results of the in vivo study indicated adequate durability of the implants.ConclusionThe graft showed morphologic evidence of good in situ cellularization, satisfactory durability to withstand arterial pressure for 12 postoperative months, and the potential to acquire physiologic vasomotor responsiveness. These results suggest that our tissue-engineered vascular graft shows promise as an arterial conduit prosthesis

Antibody titers against SARS-CoV-2 decline, but do not disappear for several months

Background: To develop an effective vaccine against a novel viral pathogen, it is important to understand the longitudinal antibody responses against its first infection. Here we performed a longitudinal study of antibody responses against SARS-CoV-2 in symptomatic patients. Methods: Sequential blood samples were collected from 39 individuals at various timepoints between 0 and 154 days after onset. IgG or IgM titers to the receptor binding domain (RBD) of the S protein, the ectodomain of the S protein, and the N protein were determined by using an ELISA. Neutralizing antibody titers were measured by using a plaque reduction assay. Findings: The IgG titers to the RBD of the S protein, the ectodomain of the S protein, and the N protein peaked at about 20 days after onset, gradually decreased thereafter, and were maintained for several months after onset. Extrapolation modeling analysis suggested that the IgG antibodies were maintained for this amount of time because the rate of reduction slowed after 30 days post-onset. IgM titers to the RBD decreased rapidly and disappeared in some individuals after 90 days post-onset. All patients, except one, possessed neutralizing antibodies against authentic SARS-CoV-2, which they retained at 90 days after onset. The highest antibody titers in patients with severe infections were higher than those in patients with mild or moderate infections, but the decrease in antibody titer in the severe infection cohort was more remarkable than that in the mild or moderate infection cohort. Interpretation: Although the number of patients is limited, our results show that the antibody response against the first SARS-CoV-2 infection in symptomatic patients is typical of that observed in an acute viral infection

A case of paraneoplastic optic neuropathy and outer retinitis positive for autoantibodies against collapsin response mediator protein-5, recoverin, and alpha-enolase

Background: Specific cross-reacting autoimmunity against recoverin or collapsin response mediator protein (CRMP)-5 is known to cause cancer-associated retinopathy or paraneoplastic optic neuropathy, respectively. We report a rare case with small cell lung carcinoma developing bilateral neuroretinitis and unilateral focal outer retinitis positive for these antibodies. Case presentation: A 67-year-old man developed bilateral neuroretinitis and foveal exudation in the right eye. Optical coherence tomography showed a dome-shaped hyperreflective lesion extending from inner nuclear layer to the photoreceptor layer at the fovea in the right eye. Single-flash electroretinography showed normal a-waves in both eyes and slightly reduced b-wave in the left eye. Results of serological screening tests for infection were within normal limits. The patient's optic disc swelling and macular exudation rapidly improved after oral administration of prednisolone. Systemic screening detected lung small cell carcinoma and systemic chemotherapy was initiated. Immunoblot analyses using the patient's serum detected autoantibodies against recoverin, CRMP-5, and a-enolase, but not carbonic anhydrase II. Neuroretinitis once resolved after almost remission of carcinoma on imaging but it recurred following the recurrence of carcinoma. Conclusions: The development of neuroretinitis in this cancer patient with anti-retinal and anti-optic nerve antibodies depended largely on the cancer activity, suggesting the possible involvement of paraneoplastic mechanisms. Patients with paraneoplastic optic neuropathy and retinopathy are likely to develop autoimmune responses against several antigens, thus leading to various ophthalmic involvements