Publications by authors named "Hyesik Kong"

20 Publications

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Integrated cell-free DNA and cytokine analysis uncovers distinct tissue injury and immune response patterns in solid organ transplant recipients with COVID-19.

Res Sq 2022 Jan 20. Epub 2022 Jan 20.

COVID-19 pathogenesis is associated with an exuberant inflammatory response. However, the tissue injury pattern and immune response in solid-organ transplant recipients (SOTRs) taking immunosuppressive therapy have not been well characterized. Here, we perform both cfDNA and cytokine profiling on plasma samples to map tissue damage, including allograft injury and delineate underlying immunopathology. We identified injuries from multiple-tissue types, including hematopoietic cells, vascular endothelium, hepatocyte, adipocyte, pancreas, kidney, heart, and lung in SOTRs with COVID-19 that correlates with disease severity. SOTRs with COVID-19 have higher plasma levels of cytokines such as IFN-λ1, IFN-γ, IL-15, IL-18 IL-1RA, IL-6, MCP-2, and TNF-α as compared to healthy controls, and the levels of GM-CSF, IL-15, IL-6, IL-8, and IL-10 were associated with disease severity in SOTRs. Strikingly, IFN-λ and IP-10 were markedly increased in SOTRs compared to immunocompetent patients with COVID-19. Correlation analyses showed a strong association between monocyte-derived cfDNA and inflammatory cytokines/chemokines in SOTRs with COVID-19. Moreover, compared to other respiratory viral infections, COVID-19 induced pronounced injury in hematopoitic, vascular endothelial and endocrine tissues. Allograft injury, measured as donor-derived cfDNA was elevated in SOTRs with COVID-19, including allografts distant from the primary site of infection. Allograft injury correlated with inflammatory cytokines and cfDNA from immune cells. Furthermore, longitudinal analysis identified a gradual decrease of cfDNA and inflammatory cytokine levels in patients with a favorable outcome. Our findings highlight distinct tissue injury and cytokine features in SOTRs with COVID-19 that correlate with disease severity.
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http://dx.doi.org/10.21203/rs.3.rs-1262270/v1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8786231PMC
January 2022

Higher levels of allograft injury in black patients early after heart transplantation.

J Heart Lung Transplant 2021 Dec 23. Epub 2021 Dec 23.

Genomic Research Alliance for Transplantation (GRAfT), Bethesda, Maryland; Laborarory of Applied Precision Omics (APO), Division of Intramural Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland; Department of Medicine, Stanford University School of Medicine, Palo Alto, California. Electronic address:

Black patients suffer higher rates of antibody-mediated rejection and have worse long-term graft survival after heart transplantation. Donor-derived cell free DNA (ddcfDNA) is released into the blood following allograft injury. This study analyzed %ddcfDNA in 63 heart transplant recipients categorized by Black and non-Black race, during the first 200 days after transplant. Immediately after transplant, %ddcfDNA was higher for Black patients (mean [SE]: 8.3% [1.3%] vs 3.2% [1.2%], p = 0.001). In the first week post-transplant, the rate of decay in %ddcfDNA was similar (0.7% [0.68] vs 0.7% [0.11], p = 0.78), and values declined in both groups to a comparable plateau at 7 days post-transplant (0.46% [0.03] vs 0.45% [0.04], p = 0.78). The proportion of Black patients experiencing AMR was higher than non-Black patients (21% vs 9% [hazard ratio of 2.61 [95% confidence interval: 0.651-10.43], p = 0.18). Black patients were more likely to receive a race mismatched organ than non-Black patients (69% vs 35%, p = 0.01), which may explain the higher levels of early allograft injury.
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http://dx.doi.org/10.1016/j.healun.2021.12.006DOI Listing
December 2021

The NIH Lipo-COVID Study: A Pilot NMR Investigation of Lipoprotein Subfractions and Other Metabolites in Patients with Severe COVID-19.

Biomedicines 2021 Aug 26;9(9). Epub 2021 Aug 26.

Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA.

A complex interplay exists between plasma lipoproteins and inflammation, as evidenced from studies on atherosclerosis. Alterations in plasma lipoprotein levels in the context of infectious diseases, particularly respiratory viral infections, such as SARS-CoV-2, have become of great interest in recent years, due to their potential utility as prognostic markers. Patients with severe COVID-19 have been reported to have low levels of total cholesterol, HDL-cholesterol, and LDL-cholesterol, but elevated levels of triglycerides. However, a detailed characterization of the particle counts and sizes of the different plasma lipoproteins in patients with COVID-19 has yet to be reported. In this pilot study, NMR spectroscopy was used to characterize lipoprotein particle numbers and sizes, and various metabolites, in 32 patients with severe COVID-19 admitted to the intensive care unit. Our study revealed markedly reduced HDL particle (HDL-P) numbers at presentation, especially low numbers of small HDL-P (S-HDL-P), and high counts of triglyceride-rich lipoprotein particle (TRL-P), particularly the very small and small TRL subfractions. Moreover, patients with severe COVID-19 were found to have remarkably elevated GlycA levels, and elevated levels of branched-chain amino acids and beta-hydroxybutyrate. Finally, we detected elevated levels of lipoproteins X and Z in most participants, which are distinct markers of hepatic dysfunction, and that was a novel finding.
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http://dx.doi.org/10.3390/biomedicines9091090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8471250PMC
August 2021

Response by Shah et al to Letter Regarding Article, "Cell-Free DNA to Detect Heart Allograft Acute Rejection".

Circulation 2021 09 7;144(10):e198-e199. Epub 2021 Sep 7.

Genomic Research Alliance for Transplantation (GRAfT), Bethesda, MD (P.S., S.A-E., I.T., S.H., E.F., K.S., M.E.R., S.S.N., H.K., U.F., A.B., A.M., K.B., Y.Y., M.K.J., C.Marboe, G.J.B., H.A.V.).

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http://dx.doi.org/10.1161/CIRCULATIONAHA.121.055697DOI Listing
September 2021

Donor-derived cell-free DNA accurately detects acute rejection in lung transplant patients, a multicenter cohort study.

J Heart Lung Transplant 2021 08 24;40(8):822-830. Epub 2021 Apr 24.

Genomic Research Alliance for Transplantation (GRAfT), 10 Center Drive, 7S261, Bethesda, Maryland; Division of Intramural Research, National Heart, Lung and Blood Institute, 10 Center Drive, 7S261, Bethesda, Maryland; Division of Pulmonary and Critical Care Medicine, The Johns Hopkins School of Medicine, 1830 East Monument Street, Baltimore, Maryland. Electronic address:

Background: Acute rejection, which includes antibody-mediated rejection and acute cellular rejection, is a risk factor for lung allograft loss. Lung transplant patients often undergo surveillance transbronchial biopsies to detect and treat acute rejection before irreversible chronic rejection develops. Limitations of this approach include its invasiveness and high interobserver variability. We tested the performance of percent donor-derived cell-free DNA (%ddcfDNA), a non-invasive blood test, to detect acute rejection.

Methods: This multicenter cohort study monitored 148 lung transplant subjects over a median of 19.6 months. We collected serial plasma samples contemporaneously with TBBx to measure %ddcfDNA. Clinical data was collected to adjudicate for acute rejection. The primary analysis consisted of computing the area-under-the-receiver-operating-characteristic-curve of %ddcfDNA to detect acute rejection. Secondary analysis determined %ddcfDNA rule-out thresholds for acute rejection.

Results: ddcfDNA levels were high after transplant surgery and decayed logarithmically. With acute rejection, ddcfDNA levels rose six-fold higher than controls. ddcfDNA levels also correlated with severity of lung function decline and histological grading of rejection. %ddcfDNA area-under-the-receiver-operating-characteristic-curve for acute rejection, AMR, and ACR were 0.89, 0.93, and 0.83, respectively. ddcfDNA levels of <0.5% and <1.0% showed a negative predictive value of 96% and 90% for acute rejection, respectively. Histopathology detected one-third of episodes with ddcfDNA levels ≥1.0%, even though >90% of these events were coincident to clinical complications missed by histopathology.

Conclusions: This study demonstrates that %ddcfDNA reliably detects acute rejection and other clinical complications potentially missed by histopathology, lending support to its use as a non-invasive marker of allograft injury.
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http://dx.doi.org/10.1016/j.healun.2021.04.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8319066PMC
August 2021

Use of donor-derived-cell-free DNA as a marker of early allograft injury in primary graft dysfunction (PGD) to predict the risk of chronic lung allograft dysfunction (CLAD).

J Heart Lung Transplant 2021 06 20;40(6):488-493. Epub 2021 Feb 20.

Laborarory of Applied Precision Omics (APO), Lung and Blood Institute (NHLBI), National Institutes of Health, Bethesda, Maryland; Genomic Research Alliance for Transplantation (GRAfT), National Heart, Lung and Blood Institute, Bethesda, Maryland; Department of Surgery, Johns Hopkins Hospital, Baltimore, Maryland. Electronic address:

Background: Primary graft dysfunction (PGD) is a risk factor for chronic lung allograft dysfunction (CLAD). However, the association between PGD and degree of allograft injury remains poorly defined. In this study, we leverage a novel biomarker for allograft injury, percentage donor-derived cell-free DNA (%ddcfDNA), to study the association between PGD, degree of allograft injury, and the development of CLAD.

Methods: This prospective cohort study recruited 99 lung transplant recipients and collected plasma samples on days 1, 3, and 7 for %ddcfDNA measurements. Clinical data on day 3 was used to adjudicate for PGD. %ddcfDNA levels were compared between PGD grades. In PGD patients, %ddcfDNA was compared between those who developed CLAD and those who did not.

Results: On posttransplant day 3, %ddcfDNA was higher in PGD than in non-PGD patients (median [IQR]: 12.2% [8.2, 22.0] vs 8.5% [5.6, 13.2] p = 0.01). %ddcfDNA correlated with the severity grade of PGD (r = 0.24, p = 0.02). Within the PGD group, higher levels of %ddcfDNA correlated with increased risk of developing CLAD (log OR(SE) 1.38 (0.53), p = 0.009). PGD patients who developed CLAD showed ∼2-times higher %ddcfDNA levels than patients who did not develop CLAD (median [IQR]: 22.4% [11.8, 27.6] vs 9.9% [6.7, 14.9], p = 0.007).

Conclusion: PGD patients demonstrated increased early posttransplant allograft injury, as measured by %ddcfDNA, in comparison to non-PGD patients, and these high %ddcfDNA levels were associated with subsequent development of CLAD. This study suggests that %ddcfDNA identifies PGD patients at greater risk of CLAD than PGD alone.
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http://dx.doi.org/10.1016/j.healun.2021.02.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8169618PMC
June 2021

Cell-free DNA maps COVID-19 tissue injury and risk of death and can cause tissue injury.

JCI Insight 2021 04 8;6(7). Epub 2021 Apr 8.

Genomic Research Alliance for Transplantation (GRAfT) and Laboratory of Applied Precision Omics, National Heart, Lung, and Blood Institute (NHLBI), NIH, Bethesda, Maryland, USA.

INTRODUCTIONThe clinical course of coronavirus 2019 (COVID-19) is heterogeneous, ranging from mild to severe multiorgan failure and death. In this study, we analyzed cell-free DNA (cfDNA) as a biomarker of injury to define the sources of tissue injury that contribute to such different trajectories.METHODSWe conducted a multicenter prospective cohort study to enroll patients with COVID-19 and collect plasma samples. Plasma cfDNA was subject to bisulfite sequencing. A library of tissue-specific DNA methylation signatures was used to analyze sequence reads to quantitate cfDNA from different tissue types. We then determined the correlation of tissue-specific cfDNA measures to COVID-19 outcomes. Similar analyses were performed for healthy controls and a comparator group of patients with respiratory syncytial virus and influenza.RESULTSWe found markedly elevated levels and divergent tissue sources of cfDNA in COVID-19 patients compared with patients who had influenza and/or respiratory syncytial virus and with healthy controls. The major sources of cfDNA in COVID-19 were hematopoietic cells, vascular endothelium, hepatocytes, adipocytes, kidney, heart, and lung. cfDNA levels positively correlated with COVID-19 disease severity, C-reactive protein, and D-dimer. cfDNA profile at admission identified patients who subsequently required intensive care or died during hospitalization. Furthermore, the increased cfDNA in COVID-19 patients generated excessive mitochondrial ROS (mtROS) in renal tubular cells in a concentration-dependent manner. This mtROS production was inhibited by a TLR9-specific antagonist.CONCLUSIONcfDNA maps tissue injury that predicts COVID-19 outcomes and may mechanistically propagate COVID-19-induced tissue injury.FUNDINGIntramural Targeted Anti-COVID-19 grant, NIH.
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http://dx.doi.org/10.1172/jci.insight.147610DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8119224PMC
April 2021

Cell-Free DNA to Detect Heart Allograft Acute Rejection.

Circulation 2021 03 13;143(12):1184-1197. Epub 2021 Jan 13.

Genomic Research Alliance for Transplantation, Bethesda, MD (S.A.-E., P.S., I.T., S.H., E.F., K.S., M.E.R., S.S.N., H.K., U.F., A.B., A.M., K.B., Y.Y., M.K.J., C.M., G.J.B., H.A.V.).

Background: After heart transplantation, endomyocardial biopsy (EMBx) is used to monitor for acute rejection (AR). Unfortunately, EMBx is invasive, and its conventional histological interpretation has limitations. This is a validation study to assess the performance of a sensitive blood biomarker-percent donor-derived cell-free DNA (%ddcfDNA)-for detection of AR in cardiac transplant recipients.

Methods: This multicenter, prospective cohort study recruited heart transplant subjects and collected plasma samples contemporaneously with EMBx for %ddcfDNA measurement by shotgun sequencing. Histopathology data were collected to define AR, its 2 phenotypes (acute cellular rejection [ACR] and antibody-mediated rejection [AMR]), and controls without rejection. The primary analysis was to compare %ddcfDNA levels (median and interquartile range [IQR]) for AR, AMR, and ACR with controls and to determine %ddcfDNA test characteristics using receiver-operator characteristics analysis.

Results: The study included 171 subjects with median posttransplant follow-up of 17.7 months (IQR, 12.1-23.6), with 1392 EMBx, and 1834 %ddcfDNA measures available for analysis. Median %ddcfDNA levels decayed after surgery to 0.13% (IQR, 0.03%-0.21%) by 28 days. Also, %ddcfDNA increased again with AR compared with control values (0.38% [IQR, 0.31-0.83%], versus 0.03% [IQR, 0.01-0.14%]; <0.001). The rise was detected 0.5 and 3.2 months before histopathologic diagnosis of ACR and AMR. The area under the receiver operator characteristic curve for AR was 0.92. A 0.25%ddcfDNA threshold had a negative predictive value for AR of 99% and would have safely eliminated 81% of EMBx. In addition, %ddcfDNA showed distinctive characteristics comparing AMR with ACR, including 5-fold higher levels (AMR ≥2, 1.68% [IQR, 0.49-2.79%] versus ACR grade ≥2R, 0.34% [IQR, 0.28-0.72%]), higher area under the receiver operator characteristic curve (0.95 versus 0.85), higher guanosine-cytosine content, and higher percentage of short ddcfDNA fragments.

Conclusions: We found that %ddcfDNA detected AR with a high area under the receiver operator characteristic curve and negative predictive value. Monitoring with ddcfDNA demonstrated excellent performance characteristics for both ACR and AMR and led to earlier detection than the EMBx-based monitoring. This study supports the use of %ddcfDNA to monitor for AR in patients with heart transplant and paves the way for a clinical utility study. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02423070.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.120.049098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8221834PMC
March 2021

Preclinical studies of the potent and selective nicotinic α4β2 receptor ligand VMY-2-95.

Mol Pharm 2015 Feb 20;12(2):393-402. Epub 2015 Jan 20.

Department of Oncology, ‡Center for Drug Discovery, and §Lombardi Comprehensive Cancer Center, Georgetown University Medical Center , 3970 Reservoir Road, Washington D.C. 20057, United States.

The discovery and development of small molecules that antagonize neuronal nicotinic acetylcholine receptors may provide new ligands for evaluation in models of depression or addiction. We discovered a small molecule, VMY-2-95, a nAChR ligand with picomolar affinity and high selectivity for α4β2 receptors. In this study, we investigated its preclinical profile in regards to solubility, lipophilicity, metabolic stability, intestinal permeability, bioavailability, and drug delivery to the rat brain. Metabolic stability of VMY-2-95·2HCl was monitored on human liver microsomes, and specific activity of VMY-2-95·2HCl on substrate metabolism by CYP1A2, 2C9, 2C19, 2D6, and 3A4 was tested in a high-throughput manner. The intestinal transport of VMY-2-95·2HCl was studied through Caco-2 cell monolayer permeability. VMY-2-95·2HCl was soluble in water and chemically stable, and the apparent partition coefficient was 0.682. VMY-2-95·2HCl showed significant inhibition of CYP2C9 and 2C19, but weak or no effect on 1A2, 2D6, and 3A4. The Caco-2 cell model studies revealed that VMY-2-95·2HCl was highly permeable with efflux ratio of 1.11. VMY-2-95·2HCl achieved a maximum serum concentration of 0.56 mg/mL at 0.9 h and was orally available with a half-life of ∼9 h. Furthermore, VMY-2-95·2HCl was detected in the rat brain after 3 mg/kg oral administration and achieved a maximal brain tissue concentration of 2.3 μg/g within 60 min. Overall, the results demonstrate that VMY-2-95·2HCl has good drug like properties and can penetrate the blood-brain barrier with oral administration.
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http://dx.doi.org/10.1021/mp5003569DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4319692PMC
February 2015

Susceptibility of glucocorticoids to colonic metabolism and pharmacologic intervention in the metabolism: implication for therapeutic activity of colon-specific glucocorticoid 21-sulfate sodium at the target site.

J Pharm Pharmacol 2012 Jan 18;64(1):128-38. Epub 2011 Nov 18.

Laboratory of Biomedicinal/Medicinal Chemistry, College of Pharmacy, Pusan National University, Busan, Korea.

Objectives: The systemic side effects of glucocorticoids have prevented their long-term use for treatment of inflammatory bowel disease. Colon-specific delivery of glucocorticoids has been adopted as a strategy to circumvent the toxicological trouble. Glucocorticoids delivered to the large intestine might undergo metabolisms by colonic microflora, which should affect therapeutic availability at the target site. It was investigated whether the susceptibility of glucocorticoids to the colonic metabolisms and pharmacologic intervention in the metabolism could modulate the therapeutic availability of colon-targeted glucocorticoids.

Methods: Various glucocorticoids and their derivatives, glucocorticoid 21-sulfate sodium compounds, were incubated in the cecal contents in the presence or absence of reduction inhibitors and the change in the levels of the drugs was monitored.

Key Findings: The accumulation profiles of the corresponding glucocorticoids liberated from glucocorticoid 21-sulfate sodium compounds vary, depending on the metabolic susceptibility of glucocorticoids. Reduction inhibitors prevented the cecal metabolisms of glucocorticoids, which was most prominent for prednisolone (PD) and methylprednisolone (MP). Moreover, reduction inhibitors increased the accumulated amount of MP and PD released from PD- and MP-21-sulfate sodium in the cecal contents.

Conclusions: Our data provide information useful for selection of a glucocorticoid and a pharmacologic strategy for the design of an efficient colon-specific glucocorticoid prodrug.
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http://dx.doi.org/10.1111/j.2042-7158.2011.01386.xDOI Listing
January 2012

Synthesis and evaluation of sulfate conjugated metronidazole as a colon-specific prodrug of metronidazole.

J Drug Target 2012 Apr 26;20(3):255-63. Epub 2011 Nov 26.

Laboratory of Biomedicinal/Medicinal Chemistry, College of Pharmacy, Pusan National University, Busan, Korea.

For an effort to improve therapeutic property of metronidazole (MTZ) which is a drug of choice for protozoal infections such as luminal amoebiasis, sulfate conjugated metronidazole (MTZS) was prepared and evaluated as a colon-specific prodrug of MTZ. The apparent partition coefficient of MTZ was greatly reduced by the sulfate conjugation. While (bio)chemically stable in the contents of the upper intestine, MTZS was rapidly cleaved to liberate MTZ on incubation with the cecal contents of rats. MTZ liberated from MTZS metabolized quickly at least partly by a microbial nitroreductase, suggesting the relevance of the metabolism to bioactivation of MTZ for antimicrobial action. Consistent with the hypothesis, MTZS elicited antibacterial activity in the cecal contents, which was as potent as free MTZ. The systemic absorption of MTZS was very low after oral administration of MTZS. In parallel with this, whereas MTZ disappeared mostly during the transit of the proximal small intestine, a substantial amount of MTZS remained in the small intestine, moving down to the large intestine where it metabolized rapidly. In addition to the efficient colonic delivery of MTZS, MTZS markedly reduced the systemic absorption of MTZ. Taken together, MTZS may be a potential colon-specific prodrug of MTZ which possesses improved therapeutic and toxicological properties.
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http://dx.doi.org/10.3109/1061186X.2011.639024DOI Listing
April 2012

Structural effects of N-aromatic acyl-amino acid conjugates on their deconjugation in the cecal contents of rats: implication in design of a colon-specific prodrug with controlled conversion rate at the target site.

Biopharm Drug Dispos 2011 Sep 29;32(6):343-54. Epub 2011 Jul 29.

Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, Republic of Korea.

N-aromatic acyl-amino acid conjugates possess a colon-targeted property, implying that such conjugates are stable and are not absorbable until reaching the large intestine in which they are microbially converted (hydrolysed) to the parent drugs that are therapeutically active. To investigate the structural effect of N-aromatic acyl-amino acid conjugates on the large intestinal deconjugation, the hydrolysis of various N-aromatic acyl-amino acid conjugates was examined in the cecal contents. On incubation of conjugates with glycine, D or/and L forms of alanine or phenylalanine in the cecal contents, the conjugates with D amino acids were not hydrolysed. The other conjugates are susceptible to the hydrolysis, the rates of which decreased as the size of the substituent on the 2-position of the amino acids increased. The conjugates with alkyl analogs (2-4 carbons) of glycine and taurine were resistant to the hydrolysis, while taurine- and glycine-conjugates were hydrolysed effectively. The hydrolysis of N-aromatic acyl-glycine conjugates was enhanced by para-substitution of electron withdrawing groups on the aromatic acyl moiety and vice versa for electron-donating groups. While a methyl, methoxy or chloro group on the ortho-position retarded the hydrolysis, a hydroxyl group on the position accelerated it. Our data may provide useful information for the design of a colon-specific prodrug with controlled conversion rate in the large intestine.
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http://dx.doi.org/10.1002/bdd.763DOI Listing
September 2011

Sulfate-conjugated methylprednisolone as a colon-targeted methylprednisolone prodrug with improved therapeutic properties against rat colitis.

J Drug Target 2009 Jul;17(6):450-8

Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA.

Methylprednisolone (MP) is one of the most widely used corticosteroids for the treatment of inflammatory bowel disease (IBD). However, systemic adverse effects of MP limit its availability for the disease. In present study, sulfate-conjugated methylprednisolone (MPS) was evaluated in vivo as a colon-targeted prodrug of MP and its therapeutic properties against 2,4,6-trinitrobenzenesulfonic acid-induced rat colitis were investigated. Upon oral administration, a large fraction of MPS reached the large intestine, where MPS was converted to MP implying that MPS would deliver MP effectively to the large intestine. The fecal recovery of MP (after MPS administration) was much greater than that after MP administration and the urinary recovery of MP (after MPS administration) was much less than that after MP administration, suggesting that MPS should exhibit enhanced therapeutic activity and reduced systemic adverse effects. Consistent with this notion, MPS was more effective than MP in ameliorating rat colitis. Moreover, the adverse effects of MPS on adrenal function and thymus were much lower than those of MP. Taken together, MPS may be therapeutically superior to MP in IBD treatment.
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http://dx.doi.org/10.1080/10611860902974077DOI Listing
July 2009

Sulfate-conjugated methylprednisolone: evaluation as a colon-specific methylprednisolone prodrug and comparison with sulfate-conjugated prednisolone and dexamethasone.

J Drug Target 2009 Feb;17(2):159-67

Urologic Oncology Branch, National Cancer Institute, Center for Cancer Research, Bethesda, MD 20892, USA.

Methylprednisolone 21-sulfate sodium (MPS) was prepared and evaluated as a colon-specific methylprednisolone prodrug and its colon-specific property was compared with prednisolone 21-sulfate sodium (PDS) and dexamethasone 21-sulfate sodium (DS), reported previously as colon-specific prodrugs of the glucocorticoids. The synthetic process and yield of MPS was simple and high. The apparent partition coefficient of methylprednisolone (MP) was greatly reduced by sulfate conjugation. The sulfate conjugates MPS, PDS, and DS were (bio)chemically stable in the homogenates of the upper intestine. In marked contrast, the sulfate conjugates were deconjugated to liberate the corresponding glucocorticoids in the cecal contents. Although the rates of deconjugation were not significantly different, the corresponding glucocorticoids were accumulated with distinct profiles depending on the metabolic susceptibility of the unconjugated glucocorticoids to microbial reductase(s). Upon oral administration of the sulfate conjugates to rats, the plasma concentrations of the conjugates were extremely low and the urinary recoveries were less than 5% of the doses. These results suggest that, like PDS and DS, MPS administered orally is delivered efficiently to the large intestine followed by deconjugation to liberate MP and the metabolic susceptibility of the unconjugated glucocorticoids may affect therapeutic availability of the sulfate conjugates.
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http://dx.doi.org/10.1080/10611860802546637DOI Listing
February 2009

Dexamethasone 21-sulfate improves the therapeutic properties of dexamethasone against experimental rat colitis by specifically delivering the steroid to the large intestine.

Pharm Res 2009 Feb 29;26(2):415-21. Epub 2008 Oct 29.

Laboratory of Biomedicinal/Medicinal Chemistry, College of Pharmacy, Pusan National University, Pusan, 609-735, Republic of Korea.

Purpose: We investigated in vivo-colon targetability and therapeutic properties of DS against experimental rat colitis.

Methods: The systemic absorption and colonic delivery of D after oral administration of DS was analyzed by examining the concentration of drugs in the GI tract, plasma, urine and feces. Therapeutic activity of DS was determined using a TNBS-induced rat colitis model. Adrenal suppression by DS administration was evaluated by monitoring the concentration of ACTH and corticosterone in the plasma.

Results: DS administered orally was delivered efficiently to the large intestine resulting in D accumulation at the target site. In addition, DS was not detectable in the plasma and was detected very low in the urine after DS administration. The fecal and urinary recovery of D (after DS administration) was much greater and less than that after D administration, suggesting that DS should exhibit enhanced therapeutic activity and reduced systemic side effects. Consistent with this notion, DS was more effective than D in healing rat colitis. Moreover, oral administration of either D or DS reduced the plasma corticosterone and ACTH levels from the normal levels, which is significantly greater for D.

Conclusion: DS is a promising colon specific prodrug that improves therapeutic properties of D.
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http://dx.doi.org/10.1007/s11095-008-9758-1DOI Listing
February 2009

Synthesis and properties of N,N'-bis(5-aminosalicyl)-L-cystine as a colon-specific deliverer of 5-aminosalicylic acid and cystine.

Drug Deliv 2008 Jan;15(1):37-42

Laboratory of Biomedicinal, College of Pharmacy, Pusan National University, Busan, Korea.

N,N(')-bis(5-aminosalicyl)-L-cystine (5-ASA-Cys) was prepared by a simple synthetic route. 5-ASA-Cys was not degraded in pH 1.2 and 6.8 buffer solutions, and in the homogenates of the upper intestine. In marked contrast, 5-ASA-Cys was deconjugated extensively to liberate 5-ASA in the cecal contents. Upon oral administration of 5-ASA-Cys to rats, the plasma concentration of 5-ASA-Cys was extremely low and the urinary recovery of 5-ASA-Cys was approximately 10% of the dose. These results suggest that 5-ASA-Cys administered orally is delivered efficiently to the large intestine followed by deconjugation to liberate 5-ASA and cystine.
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http://dx.doi.org/10.1080/10717540701828806DOI Listing
January 2008

Synthesis and in vitro evaluation of N-nicotinoylglycyl-2-(5-fluorouracil-1-yl)-D,L-glycine as a colon-specific prodrug of 5-fluorouracil.

J Drug Target 2007 Apr;15(3):199-205

Bioengineering Department, Clemson University, Clemson, SC 29634, USA.

N-Nicotinoylglycyl-2-(5-fluorouracil-1-yl)-D,L-glycine (NGFG) was synthesized as a colon-specific prodrug of 5-fluorouracil (5-FU) expecting that hydrolysis of nicotinoyl and glycyl moieties by microbial enzymes in the colon will give 2-(5-fluorouracil-1-yl)-D,L-glycine, which releases 5-FU spontaneously. To in vitro-evaluate colon targetability of NGFG, apparent partition coefficient and chemical/biochemical stability of NGFG in the contents or/and tissue of the various segments of the gastrointestinal tract were determined. Low partition coefficient and stability of NGFG in the upper intestinal condition suggested its delivery to the colon in intact form after oral administration. Incubation with rat cecal contents produced 5-FU and its metabolite about 16%. Structural modification to enhance amide hydrolysis, the rate determining step in NGFG bioactivation, is suggested.
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http://dx.doi.org/10.1080/10611860701197508DOI Listing
April 2007

Evaluation of 5-aminosalicyltaurine as a colon-specific prodrug of 5-aminosalicylic acid for treatment of experimental colitis.

Eur J Pharm Sci 2006 May 7;28(1-2):26-33. Epub 2006 Feb 7.

Lab of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea.

We previously reported that 5-aminosalicyltaurine (taurine-conjugated 5-ASA, 5-ASA-Tau) showed a potential as a colon-specific prodrug of 5-aminosalicylic acid (5-ASA) by in vitro evaluation. In this report, we in vivo-evaluated 5-ASA-Tau as a colon-specific prodrug for treatment of experimental colitis. Taurine conjugation of 5-ASA greatly reduced absorption of 5-ASA from the intestine. Oral administration of taurine-conjugated 5-ASA not only increased the colonic delivery efficiency of 5-ASA but also decreased the systemic absorption of free 5-ASA as compared with that of 5-ASA and, moreover, taurine is similarly effective to known colon-specific carriers for 5-ASA, glycine and aspartic acid, suggesting that taurine conjugation is an efficient way to increase the therapeutic effect and to reduce the adverse effects of 5-ASA. Intracolonic treatment with combined 5-ASA/taurine additively ameliorated TNBS-induced colitis rats indicating that taurine acted as not only a promoiety but also a therapeutically active agent. Furthermore, 5-ASA-Tau is slightly more effective than sulfasalazine in alleviating the colonic inflammation induced by TNBS. Taken together, our data suggest that 5-ASA-Tau is a potential colon-specific prodrug of 5-aminosalicylic acid with improved therapeutic activity against inflammatory bowel disease.
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http://dx.doi.org/10.1016/j.ejps.2005.12.005DOI Listing
May 2006

A molecular mechanism for the anti-inflammatory effect of taurine-conjugated 5-aminosalicylic acid in inflamed colon.

Mol Pharmacol 2006 Apr 11;69(4):1405-12. Epub 2006 Jan 11.

Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Busan, Korea 609-735.

In previous reports, a novel colon-specific prodrug, 5-aminosalicyltaurine (5-ASA-Tau) administered orally, is successfully delivered to and liberates 5-aminosalicylic acid (5-ASA) and taurine in the inflamed large intestine of rats. Furthermore, the prodrug ameliorates the 2,4,6-trinitrobenzene-sulfonic acid-induced colitis, and taurine acts not only as a carrier but also as an active therapeutic agent. In this study, we investigated the anti-inflammatory properties of the prodrug at a molecular level. After rectal administration of taurine, formation of taurine chloramine (TauCl) in the inflamed colonic tissue was examined using high-performance liquid chromatography. In human colon epithelial cell lines, nuclear factor-kappaB (NF-kappaB) activity was accessed using an NF-kappaB-dependent luciferase reporter gene. Protein levels were monitored by Western blotting. DNA binding activity of the NF-kappaB subunit p65 was determined using a DNA binding assay kit. A millimolar level of TauCl was formed in the inflamed tissue. TauCl inhibited tumor necrosis factor (TNF)-dependent NF-kappaB activation by modifying thiol(s) on p65 and blocking DNA binding. In addition, 5-ASA inhibited phosphorylation of p65 at serine 536, which is critical for transcriptional activity of NF-kappaB. Furthermore, combined TauCl/5-ASA treatment additively inhibited TNF-dependent NF-kappaB activation. Together, our data suggest that the colon-specific carrier taurine contributes to the clinical effect of the prodrug by potentiating the inhibitory effect of the active ingredient 5-ASA on a major proinflammatory signal, TNF-dependent NF-kappaB activation in the inflamed large intestine.
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http://dx.doi.org/10.1124/mol.105.020578DOI Listing
April 2006

Metabolic and pharmacological properties of rutin, a dietary quercetin glycoside, for treatment of inflammatory bowel disease.

Pharm Res 2005 Sep 24;22(9):1499-509. Epub 2005 Aug 24.

Laboratory of Biomedicinal Chemistry, College of Pharmacy, Pusan National University, Jangjeon-Dong, Keumjung-Gu, Pusan 609-735, Republic of Korea.

Purpose: Orally administered rutin reportedly ameliorates 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis of rats. We investigated the metabolic and pharmacological properties of rutin underlying the rutin-mediated amelioration of the rat colitis.

Methods: Apparent partition coefficients of rutin and its aglycone quercetin were compared. The biochemical/chemical stability of rutin was examined in the contents of various segments of gastrointestinal tracts of rats. Inflammatory indices were determined in the colitis rats after oral administration of rutin or rectal administration of quercetin. In human colon epithelial cells, the effect of quercetin on tumor necrosis factor-alpha (TNF-alpha)-induced nuclear factor kappa B (NFkappaB) activation was examined.

Results: The sugar residue in rutin greatly lowered the apparent partition coefficient and was rapidly deglycosylated to liberate quercetin in the cecal contents, whereas it was stable in the contents of the upper intestine. Not only oral administration of rutin but also rectal administration of quercetin remarkably ameliorated TNBS-induced colitis rats, indicating that quercetin liberated from rutin is therapeutically active. Furthermore, quercetin dose-dependently inhibited an inflammatory signal TNF-alpha-dependent NFkappaB activation.

Conclusions: Our data suggest that rutin acted as a quercetin deliverer to the large intestine and its anti-inflammatory action in TNBS-induced colitis rats may be through quercetin-mediated inhibition of TNF-alpha-induced NFkappaB activation.
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http://dx.doi.org/10.1007/s11095-005-6250-zDOI Listing
September 2005
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