Reprogramming biocatalytic futile cycles through computational engineering of stereochemical promiscuity to create an amine racemase

Repurposing the intrinsic properties of natural enzymes can offer a viable solution to current synthetic challenges through the development of novel biocatalytic processes. Although amino acid racemases are ubiquitous in living organisms, an amine racemase (AR) has not yet been discovered despite its synthetic potential for producing chiral amines. Here, we report the creation of an AR based on the serendipitous discovery that amine transaminases (ATAs) can perform stereoinversion of 2-aminobutane. Kinetic modeling revealed that the unexpected off-pathway activity results from stereochemically promiscuous futile cycles due to incomplete stereoselectivity for 2-aminobutane. This finding motivated us to engineer an S-selective ATA through in silico alanine scanning and empirical combinatorial mutations, creating an AR with broad substrate specificity. The resulting AR, carrying double point mutations, enables the racemization of both enantiomers of diverse chiral amines in the presence of a cognate ketone. This strategy may be generally applicable to a wide range of transaminases, paving the way for the development of new-to-nature racemases.

222Radon reduction in small-scale water supply systems using low-technology reduction methods in the Republic of Korea: A field research and mass balance model approach

In rural areas, low-technology radon reduction methods are essential for safe access to clean groundwater. This study monitored the radon reduction rates in small-scale groundwater-based water supply systems in the Republic of Korea and also presented a mass balance equation using physical environmental conditions from three radon reduction methods. The mass balance results showed that the radon reduction rate would be affected by the groundwater flow rate (m³/day), capacity of the drainage facility (m³), surface area of air-water interface (m²), air-water ratio (dimensionless), and ventilation system. The radon reduction order was as follows: simultaneously powered and non-powered aeration method (free-fall (60.0 %) > aeration (19.6 %) > decay (0.9 %) > diffusion (0.2 %)), low-technology non-powered aeration (free-fall (60.0 %) > decay (3.4 %) > diffusion (0.9 %)), and only storage (free-fall (35.5 %) > decay (4.4 %) > diffusion (1.1 %)). Overall, non-powered aeration using the maximum free-fall effect has the potential for use as a low-technology reduction method and natural decay during water storage is the most important factor underlying seasonal variations in the reduction effect.

Synthesis and structure-activity relationship study of saponin-based membrane fusion inhibitors against SARS-CoV-2

We previously discovered that triterpenoid saponin platycodin D inhibits the SARS-CoV-2 entry to the host cell. Herein, we synthesized various saponin derivatives and established a structure-activity relationship of saponin-based antiviral agents against SARS-CoV-2. We discovered that the C3-glucose, the C28-oligosaccharide moiety that consist of (→3)-β-d-Xyl-(1 → 4)-α-l-Rham-(1 → 2)-β-d-Ara-(1 → ) as the last three sugar units, and the C16-hydroxyl group were critical components of saponin-based coronavirus cell entry inhibitors. These findings enabled us to develop minimal saponin-based antiviral agents that are equipotent to the originally discovered platycodin D. We found that our saponin-based antiviral agents inhibited both the endosomal and transmembrane protease serine 2-mediated cell surface viral entries. Cell fusion assay experiment revealed that our newly developed compounds inhibit the SARS-CoV-2 entry by blocking the fusion between the viral and host cell membranes. The effectiveness of the newly developed antiviral agents over various SARS-CoV-2 variants hints at the broad-spectrum antiviral efficacy of saponin-based therapeutics against future coronavirus variants.

Optimal application of compressive palatal stents following mesiodens removal in pediatric patients: A Randomized Controlled Trial

Background

There is no scientific evidence supporting the choice of a palatal stent in patients who underwent removal of an impacted supernumerary tooth. We aimed to investigate the effects of palatal stents in patients who underwent supernumerary tooth removal through a palatal approach and to suggest the optimal stent thickness and material.

Material and Methods

We recruited 144 patients who underwent extraction of a supernumerary tooth between the maxillary anterior teeth. Subjects were assigned to a control group (CG) or one of four compressive palatal stent groups (CPSGs) classified by the thickness and material of the thermoplastic acrylic stent used. Palatal gingival swelling and objective indices (healing, oral hygiene, gingival, and plaque) were evaluated before surgery and on postoperative days (PODs) 3, 7, and 14; pain/discomfort and the Child Oral Health Impact Profile (COHIP) were assessed as subjective indices of the effects of the stent.

Results

The CPSGs showed faster healing than did the CG on PODs 7 (P<0.001) and 14 (P=0.043); swelling was measured by 1.64±0.88 mm and 4.52±0.39 mm, respectively. Although swelling was least in the 4-mm hard group (0.92±0.33 mm), the difference compared with that in the 2-mm hard group (1.01±0.18 mm) was not significant (P=0.077). The CPSGs showed better COHIP (P<0.001-0.036) and pain scores (P<0.001) than did the CG on PODs 1-3.

Conclusions

Compressive palatal stents reduce discomfort by decreasing pain and alleviating swelling. Although a stent is effective regardless of its thickness and material, 2-mm hard stents maximized such positive effects with minimal discomfort.

Key words:Supernumerary tooth, tooth Extraction, postoperative care, oral Health, pediatric dentistry.

Platycodin D, a natural component of Platycodon grandiflorum, prevents both lysosome- and TMPRSS2-driven SARS-CoV-2 infection by hindering membrane fusion

An ongoing pandemic of coronavirus disease 2019 (COVID-19) is now the greatest threat to global public health. Herbal medicines and their derived natural products have drawn much attention in the treatment of COVID-19, but the detailed mechanisms by which natural products inhibit SARS-CoV-2 have not been elucidated. Here, we show that platycodin D (PD), a triterpenoid saponin abundant in Platycodon grandiflorum (PG), a dietary and medicinal herb commonly used in East Asia, effectively blocks the two main SARS-CoV-2 infection routes via lysosome- and transmembrane protease serine 2 (TMPRSS2)-driven entry. Mechanistically, PD prevents host entry of SARS-CoV-2 by redistributing membrane cholesterol to prevent membrane fusion, which can be reinstated by treatment with a PD-encapsulating agent. Furthermore, the inhibitory effects of PD are recapitulated by the pharmacological inhibition or gene silencing of NPC1, which is mutated in patients with Niemann-Pick type C (NPC) displaying disrupted membrane cholesterol distribution. Finally, readily available local foods or herbal medicines containing PG root show similar inhibitory effects against SARS-CoV-2 infection. Our study proposes that PD is a potent natural product for preventing or treating COVID-19 and that briefly disrupting the distribution of membrane cholesterol is a potential novel therapeutic strategy for SARS-CoV-2 infection.

Platycodin D, a natural component of Platycodon grandiflorum, prevents both lysosome- and TMPRSS2-driven SARS-CoV-2 infection by hindering membrane fusion

An ongoing pandemic of coronavirus disease 2019 (COVID-19) is now the greatest threat to global public health. Herbal medicines and their derived natural products have drawn much attention in the treatment of COVID-19, but the detailed mechanisms by which natural products inhibit SARS-CoV-2 have not been elucidated. Here, we show that platycodin D (PD), a triterpenoid saponin abundant in Platycodon grandiflorum (PG), a dietary and medicinal herb commonly used in East Asia, effectively blocks the two main SARS-CoV-2 infection routes via lysosome- and transmembrane protease serine 2 (TMPRSS2)-driven entry. Mechanistically, PD prevents host entry of SARS-CoV-2 by redistributing membrane cholesterol to prevent membrane fusion, which can be reinstated by treatment with a PD-encapsulating agent. Furthermore, the inhibitory effects of PD are recapitulated by the pharmacological inhibition or gene silencing of NPC1, which is mutated in patients with Niemann-Pick type C (NPC) displaying disrupted membrane cholesterol distribution. Finally, readily available local foods or herbal medicines containing PG root show similar inhibitory effects against SARS-CoV-2 infection. Our study proposes that PD is a potent natural product for preventing or treating COVID-19 and that briefly disrupting the distribution of membrane cholesterol is a potential novel therapeutic strategy for SARS-CoV-2 infection.

Biochemical characterization and synthetic application of aromatic L-amino acid decarboxylase from Bacillus atrophaeus

Aromatic L-amino acid decarboxylases (AADCs) are ubiquitously found in higher organisms owing to their physiological role in the synthesis of neurotransmitters and alkaloids. However, bacterial AADC has not attracted much attention because of its rather limited availability and narrow substrate range. Here, we examined the biochemical properties of AADC from Bacillus atrophaeus (AADC-BA) and assessed the synthetic feasibility of the enzyme for the preparation of monoamine neurotransmitters. AADC-BA was expressed in Escherichia coli BL21(DE3) and the purified enzyme showed a specific activity of 2.6 ± 0.4 U/mg for 10 mM L-phenylalanine (L-Phe) at 37 °C. AADC-BA showed optimal pH and temperature ranges at 7-8 and 37-45 °C, respectively. The K_M and k_cat values for L-Phe were 7.2 mM and 7.4 s^-1, respectively, at pH 7.0 and 37 °C. Comparison of the kinetic constants at different temperatures revealed that the temperature dependency of the enzyme was mainly determined by catalytic turnover rather than substrate binding. AADC-BA showed a broad substrate scope for various aromatic amino acids, including L-Phe, L-tryptophan (610% relative to L-Phe), L-tyrosine (12%), 3,4-dihydroxyphenyl-L-alanine (24%), 5-hydroxy-L-tryptophan (L-HTP, 71%), 4-chloro-L-phenylalanine (520%), and 4-nitro-L-phenylalanine (450%). Homology modeling and docking simulations were carried out and were consistent with the observed substrate specificity. To demonstrate the synthetic potential of AADC-BA, we carried out the production of serotonin by decarboxylation of L-HTP. The reaction yield of serotonin reached 98% after 1 h at the reaction conditions of 50 mM L-HTP and 4 U/mL AADC-BA. Moreover, we carried out preparative-scale decarboxylation of L-Phe (100 mM in 40-mL reaction mixture) and isolated the resulting 2-phenylethylamine (51% recovery yield). We expect that the broad substrate specificity of AADC-BA can be exploited to produce various aromatic biogenic amines. KEY POINTS: • AADC-BA showed broad substrate specificity for various aromatic amino acids. • The substrate specificity was elucidated by in silico structural modeling. • The synthetic potential of AADC-BA was demonstrated for the production of biogenic amines.

Machine learning for predicting fractional flow reserve based on optical coherence tomography in intermediate coronary stenosis

Background

Machine learning approaches using intravascular optical coherence tomography (OCT) to predict fractional flow reserve (FFR) have not been previously investigated. The objective of the study was to evaluate a machine learning method to estimate FFR based on intravascular OCT images in intermediate coronary lesions.

Methods

Data from both OCT- and wire-based FFR methods were obtained for lesions of the left anterior descending artery in 125 patients. Based on the total number of lesions, training and testing groups were partitioned at a ratio of 5:1. For the training group, 36 features, including 16 clinical and lesion characteristics, and 21 OCT features, were used to model machine learning-FFR. machine learning-FFR values were then derived for the testing group and compared with wire-based FFR values in terms of a diagnosis of ischemia (FFR &lt;0.8).

Results

Clinical and lesion characteristics and OCT features between the training and testing groups were similar. During the machine learning modeling of the training group, six important features of machine learning-FFR were identified: minimal luminal area, percentage of the stenotic area, lesion length, proximal luminal area, pre-procedural platelet count, and hypertension. machine learning-FFR values showed a good correlation (r=0.853, P&lt;0.001) with wire-based FFR values (Figure 1A). The diagnostic power of an FFR value less than 0.8, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of machine learning-FFR values for the testing group were 85.7%, 100%, 100%, 77.8%, and 90.5%, respectively (Figure 1B). Additionally, OCT-based machine learning-FFR values showed a good diagnostic accuracy compared with other image-based FFR values.

Conclusions

The OCT-based machine learning-FFR method can be used to simultaneously acquire information on both image and functional modalities using one invasive procedure, suggesting that it may be used to optimize treatments for intermediate coronary artery stenosis, as well as save time and cost.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Funded by the Korean government (MSIT) (no. 2017R1A2B2003191)

Total Synthesis of Cinnamodial-Based Dimer (-)-Capsicodendrin

We describe the first total synthesis of cinnamodial-based dimer (-)-capsicodendrin. First, we developed a 12-step synthetic route to access (-)-cinnamodial from 1-vinyl-2,6,6-trimethylcyclohexene. We then showed that (-)-cinnamodial can selectively dimerize to (-)-capsicodendrin under kinetically controlled basic conditions. Our observations regarding a facile conversion of (-)-capsicodendrin back to (-)-cinnamodial hint at the possibility that (-)-capsicodendrin is a chemical reservoir of insecticidal (-)-cinnamodial and Cinnamosma genus plants release it upon environmental stresses.

Modification of the RANKL-RANK-binding site for the immunotherapeutic treatment of osteoporosis

Here, we proposed the use of mutated RANKL as an immunogen for active immunization and to induce anti-cytokine antibodies for osteoporosis treatment.

INTRODUCTION

Osteoclasts are responsible for bone resorption in bone-related disorders. Anti-cytokine therapeutic antibodies such as denosumab are effective for the treatment of osteoporosis. However, problems with antibody manufacturing and the immunogenicity caused by multiple antibody doses have led to the use of auto-cytokines as immunogens to induce anti-cytokine antibodies.

METHODS

RANKL was point-mutated based on the crystal structure of the complex of RANKL and its receptor RANK.

RESULTS

As a proof of concept, immunization with RANKL produced high levels of specific antibodies and blocked osteoclast development in vitro and inhibited osteoporosis in RANKL-treated or ovariectomized mouse models.

CONCLUSIONS

The results demonstrate the successful use of mutated RANKL as an immunogen for the induction of anti-RANKL immune response. This strategy is useful in general anti-cytokine immunotherapy to avoid toxic side effects of osteoporosis treatment.

P4393Current smoking and gender difference in South Korean AMI patients who underwent PCI with DES

Background

There is some debate on whether or not there is a gender difference is present between current smoking and cardiovascular disease.

Purpose

We decide to evaluate the impact of sex difference on the 2-year clinical outcomes in Korean acute myocardial infarction (AMI) patients who currently smoke and who underwent percutaneous coronary intervention (PCI) with drug-eluting stents (DES).

Methods

The data of this study was obtained from the Korea Acute Myocardial Infarction (KAMIR) registry. More than fifty high-volume universites or community hospitals with facilities for primary PCI and onsite cardiac surgery participated in this KAMIR registry. A total of 12565 current smoker AMI patients were enrolled and divided into the male (n=11767, 93.6%) or female (n=798, 6.4%) group. The clinical endpoint was the occurrence of major adverse cardiac events (MACE) defined as all-cause death, recurrent myocardial infarction (re-MI), and total repeat revascularization.

Results

Before risk adjustment, the cumulative incidences of MACE (7.2% vs. 10.0%, hazard ratio [HR], 1.419; 95% confidence interval [CI], 1.125–1.790; P=0.003), all-cause death (HR, 1.988; 95% CI, 1.417–2.789; P<0.001), and re-MI (HR, 1.885; 95% CI, 1.154–3.078; P=0.011) were significantly higher in the female group compared with the male group. However, after adjustment the cumulative incidences of MACE (adjusted HR, 1.047; 95% CI, 0.756–1.450; P=0.782), all-cause death, re-MI, total repeat revascularization, TLR, TVR, and non-TVR were similar between the two groups.

Clinical outcomes at 2-year Outcomes Cumulative Events at 2-year (%) Unadjusted Adjusted* Propensity-score adjusted Male Female Log-rank Hazard Ratio (95% CI) p value Hazard Ratio (95% CI) p value Hazard Ratio (95% CI) p value MACE 819 (7.2) 78 (10.0) 0.003 1.419 (1.125–1.790) 0.003 1.047 (0.756–1.450) 0.782 1.133 (0.871–1.473) 0.352 All-cause death 283 (2.5) 38 (4.8) <0.001 1.988 (1.417–2.789) <0.001 0.764 (0.457–1.279) 0.306 1.105 (0.744–1.641) 0.620 Cardiac death 224 (1.9) 25 (3.2) 0.016 1.654 (1.094–2.500) 0.017 0.512 (0.261–1.005) 0.052 0.822 (0.511–1.322) 0.419 Re-MI 142 (1.3) 18 (2.4) 0.010 1.885 (1.154–3.078) 0.011 1.741 (0.887–3.419) 0.107 1.835 (1.109–3.375) 0.062 Total revascularization 444 (4.0) 27 (3.6) 0.594 0.900 (0.610–1.327) 0.594 1.069 (0.654–1.748) 0.789 0.956 (0.627–1.458) 0.835 TLR 121 (1.1) 8 (1.1) 0.956 0.980 (0.479–2.004) 0.956 0.955 (0.366–2.497) 0.926 0.868 (0.395–1.910) 0.726 TVR 228 (2.1) 14 (1.9) 0.726 0.908 (0.529–1.558) 0.726 1.051 (0.518–2.135) 0.890 0.935 (0.519–1.684) 0.823 Non-TVR 223 (2.0) 13 (1.7) 0.602 0.862 (0.493–1.508) 0.602 1.060 (0.536–2.097) 0.867 0.942 (0.514–1.726) 0.847

Conclusion

Before risk adjustment, a gender difference was suggested in the female group compared with the male in these current smoker South Korean AMI patients during a 2-year follow-up period. However, after adjustment, gender difference was not observed in these AMI patients with a history of current smoking.

P833Two-year clinical outcomes between statin with ACE inhibitor or ARB in patients with ST-segment elevation myocardial infarction after successful PCI with DES

Background

Limited comparative data are available.

Purpose

We decided to compare 2-year major clinical outcomes between statin with ACEI and statin ARB therapy in patients with STEMI after PCI with drug-eluting stents (DES).

Methods

A total 11706 STEMI patients who underwent PCI with DES and who prescribed statin were enrolled and they were divided into two groups, the statin with ACEI group (n=8705) and the statin with ARB group (n=3001). The primary endpoint was the major adverse cardiac events (MACE) defined as all-cause death, recurrent myocardial infarction (re-MI), target lesion revascularization (TLR), target vessel revascularization (TVR), non-TVR. The secondary endpoints were the cumulative incidences of individual components of MACE and target vessel failure (TVF), a composite of death related to the target vessel, re-MI, or clinically driven TVR.

Results

Two PSM groups (2835 pairs, n=5670, C-statistic = 0.680) were generated. The relative risk of MACE was higher in the statin with ARB group compared to statin with ACEI groups after propensity score-matched (PSM) analysis (hazard ratio [HR]: 1.323, 95% confidence interval [CI]: 1.085–1.613, p=0.006). The relative risks of cardiac death (HR: 1.831, 95% CI: 1.199–2.740, p=0.005), total repeat revascularization (HR: 1.487, 95% CI: 1.133–1.950, p=0.004), and non-TVR (HR: 1.696, 95% CI: 1.122–2.564, p=0.012) were also higher in the statin with ARB group after PSM.

Outcomes Cumulative Events at 2-year (%) Hazard Ratio (95% CI) p value Statin + ACEI Statin + ARB Log-rank Propensity score matched Patients MACE 173 (6.5) 225 (8.5) 0.006 1.323 (1.085–1.613) 0.006 All-cause death 58 (2.2) 80 (3.0) 0.054 1.391 (0.992–1.950) 0.056 Cardiac death 35 (1.3) 63 (2.3) 0.004 1.831 (1.199–2.740) 0.005 Re-MI 39 (1.5) 44 (1.7) 0.548 1.141 (0.742–1.756) 0.548 Total repeat revascularization 88 (3.4) 128 (4.9) 0.004 1.487 (1.133–1.950) 0.004 TLR 26 (1.0) 40 (1.5) 0.075 1.561 (0.953–2.558) 0.077 TVR 53 (2.0) 71 (2.8) 0.086 1.364 (0.955–1.946) 0.088 Non-TVR 36 (1.4) 60 (2.3) 0.011 1.696 (1.122–2.564) 0.012 TVF 140 (5.3) 173 (6.6) 0.050 1.249 (1.000–1.561) 0.050

Conclusions

In this study, we suggest that the combination of statin with ACEI may be beneficial for reducing the cumulative incidences of MACE, total repeat revascularization rate, and non-TVR rather than the statin with ARB after PCI with DES in STEMI patients.

P5362Impact of statin therapy on long-term clinical outcomes between STEMI and NSTEMI after stent implantation

Background

Although European guideline recommends that statin should be given to all patients with acute myocardial infarction (AMI), irrespective of cholesterol concentration, limited studies were focused on the long-term effects of statin therapy between ST-segment elevation MI (STEMI) and non-ST-segment elevation MI (NSTEMI).

Purpose

The authors conducted the study to compare the relative beneficial role of statin on 2-year major clinical outcomes between STEMI and NSTEMI in patients who underwent successful PCI with DES.

Methods

Finally, a total of 26317 AMI patients who underwent stent implantation and who were prescribed the statin were enrolled and they were separated into two groups; the STEMI group (n=15002) and the NSTEMI group (n=11315). The clinical endpoint was the occurrence of major adverse cardiac events (MACE) defined as all-cause death, recurrent myocardial infarction (re-MI), total coronary revascularization (target lesion revascularization [TLR], target vessel revascularization [TVR], non-TVR) during 2-year follow-up period.

Results

After propensity score-matched (PSM) analysis, two PSM groups (7746 pairs, n=15492, C-statistic = 0.766) were generated. In the total study population, the cumulative incidences of MACE, all-cause death, and cardiac death were significantly higher in the NSTEMI group. However, after PSM, the cumulative incidence of all-cause death (Hazard ratio, 1.386; 95% CI, 1.133–1.696; p=0.002) was significantly higher in the NSTEMI group. The cumulative incidences of MACE, cardiac death, re-MI, total revascularization, TLR, TVR, and non-TVR were similar between the two groups (Table 1).

Outcomes Cumulative Events at 2-year (%) Hazard Ratio (95% CI) p value STEMI NSTEMI Log-rank Propensity score matched patients MACE 532 (7.2) 584 (8.1) 0.092 1.106 (0.984–1.244) 0.092 All-cause death 163 (2.2) 224 (3.1) 0.001 1.386 (1.133–1.696) 0.002 Cardiac death 121 (1.5) 148 (2.0) 0.088 1.232 (0.969–1.566) 0.089 Re-MI 117 (1.6) 107 (1.5) 0.545 0.922 (0.710–1.199) 0.545 Total revascularization 291 (4.1) 307 (4.4) 0.422 1.068 (0.910–1.254) 0.423 TLR 92 (1.3) 89 (1.2) 0.880 0.978 (0.731–1.309) 0.880 TVR 173 (2.4) 184 (2.6) 0.478 1.078 (0.876–1.327) 0.478 Non-TVR 123 (1.7) 130 (1.9) 0.593 1.070 (0.836–1.369) 0.539

Conclusion

The mortality reduction capability of statin was more prominent in the STEMI group compared with the NSTEMI group.

P5494Impact of the gender difference on long-term clinical outcomes in dyslipidemic South Korean AMI patients who underwent PCI with new-generation DES

Background

There are limited comparative data concerning long-term major clinical outcomes between male and female in dyslipidemic AMI patients after PCI with new-generation DES.

Purpose

We thought to investigate the impact of gender difference on the 2-year clinical outcomes.

Methods

Finally, a total of 2403 eligible dyslipidemic AMI patients who underwent PCI with new-generation DES were enrolled and they were separated into two groups; the male group (n=1800) and the female group (n=603). The primary endpoint was major adverse cardiac events (MACE) defined as all-cause death, recurrent myocardial infarction (re-MI), target lesion revascularization (TLR), and target vessel revascularization (TVR). The secondary endpoints were the incidence of the individual components of MACE and target vessel failure (TVF), a composite of death related to the target vessel, re-MI, or clinically driven TVR

Results

Two propensity score-matched (PSM) groups (422 pairs, n=844, C-statistic = 0.850) were generated. In the total study population, the cumulative incidences of MACE, all-cause death, re-MI, and TVF were significantly higher in the female group compared with the male group. However, after propensity score-matched (PSM) analysis, the cumulative incidences of MACE (HR, 0.971; 95% CI, 0.628–1.501; p=0.895), all-cause death (HR, 1.061; 95% CI, 0.536–2.100; p=0.865), re-MI (HR, 1.212; 95% CI, 0.433–2.907; p=0.813), and TVF (HR, 0.764; 95% CI, 0.474–1.229; p=0.267) were similar between the two groups. In addition, the cumulative incidences of cardiac death, TLR, TVR were not significantly different between the two groups (Table 1).

Outcomes Cumulative Events at 2-year (%) Hazard Ratio (95% CI) p value Male Female Log-rank Propensity score matched patients MACE 41 (10.4) 40 (10.3) 0.895 0.971 (0.628–1.501) 0.895 All-cause death 16 (4.0) 17 (4.2) 0.865 1.061 (0.536–2.100) 0.865 Cardiac death 13 (3.3) 9 (2.2) 0.391 0.691 (0.295–1.616) 0.393 Re-MI 8 (2.0) 9 (2.4) 0.813 1.212 (0.433–2.907) 0.813 TLR 7 (1.8) 6 (1.6) 0.781 0.857 (0.298–2.550) 0.781 TVR 16 (4.3) 10 (2.7) 0.236 0.623 (0.283–1.373) 0.241 TVF 39 (10.2) 30 (7.8) 0.265 0.764 (0.474–1.229) 0.267

Conclusion

The gender difference was not apparent in these dyslipidemic South Korean AMI patients who underwent PCI with new-generation DES during 2-year follow-up period.

Hypoxia improves hair inductivity of dermal papilla cells via nuclear NADPH oxidase 4-mediated reactive oxygen species generation'

BACKGROUND

Dermal papilla cells (DPCs) play a key role in hair regeneration and morphogenesis. Therefore, tremendous efforts have been made to promote DPC hair inductivity.

OBJECTIVES

The aim of this study was to investigate the mitogenic and hair inductive effects of hypoxia on DPCs and examine the underlying mechanism of hypoxia-induced stimulation of DPCs.

METHODS

DPCs' hair inductivity was examined under normoxia (20% O₂ ) and hypoxia (2% O₂ ).

RESULTS

Hypoxia significantly increased the proliferation and delayed senescence of DPCs via Akt phosphorylation and downstream pathways. Hypoxia upregulated growth factor secretion of DPCs through the mitogen-activated protein kinase pathway. Hypoxia-preconditioned DPCs induced the telogen-to-anagen transition in C₃ H mice, and also enhanced hair neogenesis in a hair reconstitution assay. Injected green fluorescent protein-labelled DPCs migrated to the outer root sheath of the hair follicle, and hypoxia-preconditioning increased survival and migration of DPCs in vivo. Conditioned medium obtained from hypoxia increased the hair length of mouse vibrissa follicles via upregulation of alkaline phosphatase, vascular endothelial growth factor, and glial cell line-derived neurotrophic factor. We examined the mechanism of this hypoxia-induced stimulation, and found that reactive oxygen species (ROS) play a key role. For example, inhibition of ROS generation by N-acetylcysteine or diphenyleneiodonium treatment attenuated DPCs' hypoxia-induced stimulation, but treatment with ROS donors induced mitogenic effects and anagen transition. NADPH oxidase 4 is highly expressed in the DPC nuclear region, and NOX4 knockout by CRISPR-Cas9 attenuated the hypoxia-induced stimulation of DPCs.

CONCLUSIONS

Our results suggest that DPC culture under hypoxia has great advantages over normoxia, and is a novel solution for producing DPCs for cell therapy. What's already known about this topic? Dermal papilla cells (DPCs) play a key role in hair regeneration and morphogenesis, but they are difficult to isolate and expand for use in cell therapy. Tremendous efforts have been made to increase proliferation of DPCs and promote their hair formation ability. What does this study add? Hypoxia (2% O₂ ) culture of DPCs increases proliferation, delays senescence and enhances hair inductivity of DPCs. Reactive oxygen species play a key role in hypoxia-induced stimulation of DPC. What is the translational message? Preconditioning DPCs under hypoxia improves their hair regenerative potential, and is a novel solution for producing DPCs for cell therapy to treat hair loss.

Associations of a social network typology with physical and mental health risks among older adults in South Korea

OBJECTIVES

The objectives of this study were to (1) develop an empirical typology of social networks in older Koreans; and (2) examine its effect on physical and mental health.

METHOD

A sample of 6900 community-dwelling older adults in South Korea was drawn from the 2014 Korean National Elderly Survey. Latent profile analysis (LPA) was conducted to derive social network types using eight common social network characteristics (marital status, living arrangement, the number and frequency of contact with close family/relatives, the number and frequency of contact with close friends, frequency of participation in social activities, and frequency of having visitors at home). The identified typologies were then regressed on self-rated health and depressive symptoms to explore the health risks posed by the group membership.

RESULTS

The LPA identified a model with five types of social network as being most optimal (BIC = 153,848.34, entropy = .90). The groups were named diverse/family (enriched networks with more engagement with family), diverse/friend (enriched networks with more engagement with friends), friend-focused (high engagement with friends), distant (structurally disengaged), and restricted (structurally engaged but disengaged in family/friends networks). A series of regression analyses showed that membership in the restricted type was associated with more health and mental health risks than all types of social networks except the distant type.

CONCLUSION

Findings demonstrate the importance of family and friends as a source of social network and call attention to not only structural but also non-structural aspects of social isolation. Findings and implications are discussed in cultural contexts.

Cardioprotective Effect of the SDF-1α/CXCR4 Axis in Ischemic Postconditioning in Isolated Rat Hearts

BACKGROUND AND OBJECTIVES

Information about the role of the stromal cell-derived factor-1α (SDF-1α)/chemokine receptor type 4 (CXCR4) axis in ischemic postconditioning (IPOC) is currently limited. We hypothesized that the SDF-1α/CXCR4 signaling pathway is directly involved in the cardioprotective effect of IPOC.

METHODS

Isolated rat hearts were divided into four groups. The control group was subjected to 30-min of regional ischemia and 2-hour of reperfusion (n=12). The IPOC group was induced with 6 cycles of 10-second reperfusion and 10-second global ischemia (n=8) in each cycle. The CXCR4 antagonist, AMD3100, was applied before reperfusion in the IPOC group (AMD+IPOC group, n=11) and control group (AMD group, n=9). Hemodynamic changes with electrocardiography were monitored and infarct size was measured. The SDF-1α, lactate dehydrogenase (LDH) and creatine kinase (CK) concentrations in perfusate were measured. We also analyzed extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt phosphorylation state expression.

RESULTS

IPOC significantly reduced infarct size, but AMD3100 attenuated the infarct reducing effect of IPOC. IPOC significantly decreased LDH and CK, but these effects were reversed by AMD3100. ERK1/2 and Akt phosphorylation increased with IPOC and these effects were blocked by AMD3100.

CONCLUSION

Based on the results of this study, SDF-1α/CXCR4 signaling may be involved in IPOC cardioprotection and this signaling pathway couples to the ERK1/2 and Akt pathways.

Effect of Insufficient Light Exposure on Polymerization Kinetics of Conventional and Self-adhesive Dual-cure Resin Cements

Objectives: The purpose of this study was to investigate the influence of insufficient light exposure on the polymerization of conventional and self-adhesive dual-cure resin cements under ceramic restorations.

Methods: Two conventional dual-cure resin cements (Rely-X ARC, Duolink) and two self-adhesive resin cements (Rely-X U200, Maxcem Elite) were polymerized under different curing modes (dual-cure or self-cure), curing times (20 and 120 seconds), and thickness of a ceramic overlay (2 and 4 mm). Polymerization kinetics was measured by Fourier transform infrared spectroscopy for the initial 10 minutes and after 24 hours. Data were analyzed using mixed model analysis of variance (ANOVA), one-way ANOVA/Student-Newman-Keuls post hoc test, and paired t-test (α=0.05).

Results: When light-curing time was set to 20 seconds, the presence of the ceramic block significantly affected the degree of conversion (DC) of all resin cements. Especially, the DC of the groups with 20 seconds of light-curing time under 4 mm of ceramic thickness was even lower than that of the self-cured groups at 24 hours after polymerization (p&lt;0.05). However, when light-curing time was set to 120 seconds, a similar DC compared with the group with direct light exposure (p&gt;0.05) was achieved in all dual-cure groups except Maxcem Elite, at 24 hours after polymerization.

Conclusions: For both conventional and self-adhesive dual-cure resin cements, insufficient light exposure (20 seconds of light-curing time) through thick ceramic restoration (4 mm thick) resulted in a DC even lower than that of self-curing alone.

Distribution of Porcine Endogenous Retrovirus in Different Organs of the Hybrid of a Landrace and a Jeju Domestic Pig in Korea

Xenotransplantation offers a solution to the shortage of available organs for transplantation, and the pig represents an ideal source of such organs. However, porcine endogenous retrovirus (PERV), whose genome is integrated in pigs, has been suggested to pose a potential risk of xenotransmission. Expression of PERVs in different organs of pigs was carefully measured at DNA, mRNA, and protein levels, providing information valuable for the application of pig organs in xenotransplantation. An analysis of PERV DNA showed that a very similar number of PERV copies was present in the genome of all organs, whereas mRNA and protein levels of PERV varied depending on the organ, with kidney, liver, and spleen expressing high levels of both mRNA and protein. In contrast, mRNA and protein levels were dissimilar in the lung and brain, where mRNA levels were low but protein levels were high. This discrepancy indicates that mRNA levels are not always reflected in protein expression. In addition, the difference between mRNA and protein highlights the importance of choosing the proper analysis method for diagnosing viral infection. In summary, this study provides insight into the distribution of PERV in various organs at the DNA, mRNA, and protein levels, and also informs the proper selection of tissues or organs for future clinical xenotransplantation.

Effects of Palm Kernel Expellers on Productive Performance, Nutrient Digestibility, and White Blood Cells of Lactating Sows

This experiment was conducted to investigate the effects of palm kernel expellers on productive performance, nutrient digestibility, and changes in white blood cells (WBC) of lactating sows. A total of 14 sows (200±12 kg of average body weight [BW]; 2.5 of average parity) were used and moved from gestation room to farrowing room on d 109 of gestation. Sows were randomly assigned to 2 dietary treatments in a completely randomized design. The treatments were a diet based on corn and soybean meal (CON) and CON added with 20% of palm kernel expellers (PKE). Sows were fed the treatments for 28 days (weaning) after farrowing. Blood was collected from each sow and 4 randomly selected piglets from each sow before farrowing or on d 3, 7, or 14 of lactation. Sows were fed respective treatments containing 0.2% chromic oxide from d 15 to 21 of lactation. Fecal samples were collected daily for the last 3 days after the 4-d adjustment period. Measurements were performances and WBC changes of sows and litter, nutrient digestibility of sows, and daily diarrhea of litter. Sows fed PKE had greater average daily feed intake (7.38 vs 7.10 kg/d; p<0.05) and lost less BW (−6.85 vs −8.54 kg; p<0.05) and backfat depth (−0.42 vs −0.71 mm; p<0.05) than those fed CON. However, there were no differences on digestibility of dry matter, nitrogen, and energy and weaning to estrus interval of sows fed either CON or PKE. Piglets from sows fed PKE gained more BW (203 vs 181 g/d; p = 0.08) and had less frequency of diarrhea (6.80 vs 8.56%; p = 0.07) than those from sows fed CON. On the other hand, no difference was found on preweaning mortality of piglets from sows fed either CON or PKE. Sows fed PKE had lower number of WBC (9.57 vs 11.82 ×10³/μL; p = 0.09) before farrowing than those fed CON, but no difference on d 3 and 7. Similarly, piglets from sows fed PKE had also lower number of WBC (7.86 vs 9.80 ×10³/μL; p<0.05) on d 14 of lactation than those from sows fed CON, but no difference on d 3 and 7. In conclusion, addition of 20% palm kernel expellers to lactation diet based on corn and soybean meal had no negative effects on productive performance, nutrient digestibility, and WBC changes of lactating sows.

Effects of Palm Kernel Expellers on Growth Performance, Nutrient Digestibility, and Blood Profiles of Weaned Pigs

This experiment was conducted to investigate the effects of palm kernel expellers on growth performance, nutrient digestibility, and blood profiles of weaned pigs. A total of 88 weaned pigs (6.94±0.76 kg body weight [BW]; 28 d old) were randomly allotted to 2 dietary treatments (4 pigs/pen; 11 replicates/treatment) in a randomized complete block design (sex as a block). The dietary treatments were a typical nursery diet based on corn and soybean meal (CON) and CON added with 20% of palm kernel expellers (PKE). Pigs were fed for 6 wk using a 3-phase feeding program with declining diet complexity and with phases of 1, 2, and 3 wk, respectively. Blood was collected from randomly selected 2 pigs in each pen before weaning and on d 7 after weaning. Pigs were fed respective dietary treatments containing 0.2% chromic oxide from d 29 to 35 after weaning. Fecal samples were collected from randomly selected 2 pigs in each pen daily for the last 3 days after the 4-d adjustment period. Measurements were growth performances, digestibility of dry matter, nitrogen and energy, white and red blood cell counts, packed cell volume, and incidence of diarrhea. The PKE increased average daily gain (ADG) (246 vs 215 g/d; p = 0.06) and average daily feed intake (ADFI) (470 vs 343 g/d; p<0.05) and decreased gain-to-feed ratio (G:F) (0.522 vs 0.628 g/g; p<0.05) during phase 2 compared with CON, but did not affect growth performance during phase 1 and 3. During overall experimental period, PKE increased ADG (383 vs 362 g/d; p = 0.05) and ADFI (549 vs 496 g/d; p<0.05) compared with CON, but did not affect G:F. However, no differences were found on digestibility of dry matter, nitrogen, and energy between CON and PKE. The PKE reduced frequency of diarrhea (15% vs 25%; p = 0.08) for the first 2 wk after weaning compared with CON. Similarly, PKE decreased white blood cells (8.19 vs 9.56×10(3)/μL; p = 0.07), red blood cells (2.92 vs 3.25×10(6)/μL; p = 0.09), and packed cell volume (11.1% vs 12.6%; p = 0.06) on d 7 after weaning compared with CON. In conclusion, addition of 20% palm kernel expellers to nursery diet based on corn and soybean meal had no negative effects on growth performance, nutrient digestibility, and blood profiles of weaned pigs.

γ-Secretase inhibition promotes fibrotic effects of albumin in proximal tubular epithelial cells

BACKGROUND AND PURPOSE

Albuminuria is an important biomarker of renal dysfunction and is a major mediator of renal damage and fibrosis during kidney disease. The mechanisms underlying albumin-induced renal fibrosis remain unclear. There has been significant interest in γ-secretase activity in tubular epithelial cells in recent times; however, its potential role in albumin-induced fibrosis has not been investigated.

EXPERIMENTAL APPROACH

The primary aim of this study was to examine the role of γ-secretase in albumin-induced fibrotic effects in proximal tubular cells. The effects of increasing albumin concentrations on fibrosis indicators and mediators in the human HK-2 cell line were examined in the presence and absence of a γ-secretase inhibitor, compound E.

KEY RESULTS

Treatment with albumin resulted in a number of pro-fibrotic effects, including up-regulation of fibronectin, TGF-β1 and the EGF-R. Interestingly, similar effects were observed in response to treatment with the γ-secretase inhibitor, compound E. Co-treatment of cells with albumin and an EGF-R inhibitor, AG-1478, resulted in significant inhibition of the observed pro-fibrotic effects, suggesting a major role for the EGF-R in albumin-induced fibrotic events. Albumin-induced effects on the EGF-R appeared to be mediated through inhibition of γ-secretase activity and were dependent on ERK-MAPK signalling.

CONCLUSIONS AND IMPLICATIONS

These results provide novel insights into the mechanisms of albumin-induced fibrotic effects in tubular epithelial cells, suggesting important roles for the γ-secretase and the EGF-R. These results suggest that the proposed use of γ-secretase inhibitors as anti-fibrotic agents requires further investigation.