Publications by authors named "Hyung-Jin Yoo"

12 Publications

  • Page 1 of 1

A Randomized Phase 2 Study of Pembrolizumab With or Without Radiation in Patients With Recurrent or Metastatic Adenoid Cystic Carcinoma.

Int J Radiat Oncol Biol Phys 2021 Jan 8;109(1):134-144. Epub 2020 Aug 8.

Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts. Electronic address:

Purpose: We evaluated the safety and efficacy of pembrolizumab (pembro) ± radiation therapy (RT) in a phase 2 study among patients with progressive, metastatic adenoid cystic carcinoma (ACC).

Methods And Materials: Eligible patients had metastatic ACC with progression within the last year and ≥1 measurable lesion. Patients were randomized to pembro alone or with RT to 30 Gy in 5 fractions (pembroRT). The primary endpoint was objective response rate outside the RT field. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and local RT responses.

Results: We randomized 20 patients (10 per arm) from 2017 to 2018. We did not observe objective response outside of the radiation treatment field; stable disease (SD) was the best response in 12 (60%) patients and was not different per arm (7 pembro, 5 pembroRT, P = .65). A tumor growth rate decrease (TGR) of >25% was noted among 7 of 12 patients and >75% in 4 patients. There were local responses in the irradiated field among all evaluable pembroRT patients. Median PFS and OS were 4.5/not reached for pembroRT and 6.6 / 27.2 months for pembro patients. One patient developed grade 3 liver enzyme elevation after 27 cycles of therapy. Correlative analyses confirm low levels of programmed death-ligand 1 expression (PD-L1), and CD8 infiltrating T-cells. We identified associations between local response and both MYB/NFIB translocation and PD-L1 expression and between changes in systemic immune populations and RT.

Conclusions: Pembrolizumab and pembroRT were well tolerated. We observed no objective responses, but 60% of patients with PD before the study achieved SD, the majority with decreased TGR and half (n = 10) with clinical benefit (SD >6 months). We observed favorable local responses within the RT field. Additional strategies are needed to further delay progression and effect response.
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http://dx.doi.org/10.1016/j.ijrobp.2020.08.018DOI Listing
January 2021

Systemically Administered Hemostatic Nanoparticles for Identification and Treatment of Internal Bleeding.

ACS Biomater Sci Eng 2019 May 2;5(5):2563-2576. Epub 2019 May 2.

Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.

Internal bleeding is an injury that can be difficult to localize and effectively treat without invasive surgeries. Injectable polymeric nanoparticles have been developed that can reduce clotting times and blood loss, but they have yet to incorporate sufficient diagnostic capabilities to assist in identifying bleeding sources. Herein, polymeric nanoparticles were developed to simultaneously treat internal bleeding while incorporating tracers for visualization of the nanoparticles by standard clinical imaging modalities. Addition of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate (DiD; a fluorescent dye), biotin functionality, and gold nanoparticles to hemostatic polymeric nanoparticles resulted in nanoparticles amenable to imaging with near-infrared (NIR) imaging, immunohistochemistry, and X-ray computed tomography (CT), respectively. Following a lethal liver resection injury, visualization of accumulated nanoparticles by multiple imaging methods was achieved in rodents, with the highest accumulation observed at the liver injury site, resulting in improved survival rates. Tracer addition to therapeutic nanoparticles allows for an expansion of their applicability, during stabilization by first responders to diagnosis and identification of unknown internal bleeding sites by clinicians using standard clinical imaging modalities.
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http://dx.doi.org/10.1021/acsbiomaterials.9b00054DOI Listing
May 2019

Revascularization and muscle adaptation to limb demand ischemia in diet-induced obese mice.

J Surg Res 2016 09 8;205(1):49-58. Epub 2016 Jun 8.

Division of Vascular and Endovascular Surgery, Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts.

Background: Obesity and type 2 diabetes are major risk factors for peripheral arterial disease in humans, which can result in lower limb demand ischemia and exercise intolerance. Exercise triggers skeletal muscle adaptation including increased vasculogenesis. The goal of this study was to determine whether demand ischemia modulates revascularization, fiber size, and signaling pathways in the ischemic hind limb muscles of mice with diet-induced obesity (DIO).

Materials And Methods: DIO mice (n = 7) underwent unilateral femoral artery ligation and recovered for 2 wks followed by 4 wks with daily treadmill exercise to induce demand ischemia. A parallel sedentary ischemia (SI) group (n = 7) had femoral artery ligation without exercise. The contralateral limb muscles of SI served as control. Muscles were examined for capillary density, myofiber cross-sectional area, cytokine levels, and phosphorylation of STAT3 and ERK1/2.

Results: Exercise significantly enhanced capillary density (P < 0.01) and markedly lowered cross-sectional area (P < 0.001) in demand ischemia compared with SI. These findings coincided with a significant increase in granulocyte colony-stimulating factor (P < 0.001) and interleukin-7 (P < 0.01) levels. In addition, phosphorylation levels of STAT3 and ERK1/2 (P < 0.01) were increased, whereas UCP1 and monocyte chemoattractant protein-1 protein levels were lower (P < 0.05) without altering vascular endothelial growth factor and tumor necrosis factor alpha protein levels. Demand ischemia increased the PGC1α messenger RNA (P < 0.001) without augmenting PGC1α protein levels.

Conclusions: Exercise-induced limb demand ischemia in the setting of DIO causes myofiber atrophy despite an increase in muscle capillary density. The combination of persistent increase in tumor necrosis factor alpha, lower vascular endothelial growth factor, and failure to increase PGC1α protein may reflect a deficient adaption to demand ischemia in DIO.
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http://dx.doi.org/10.1016/j.jss.2016.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5021992PMC
September 2016

Effect of limb demand ischemia on autophagy and morphology in mice.

J Surg Res 2015 Oct 9;198(2):515-24. Epub 2015 Apr 9.

Division of Vascular and Endovascular Surgery, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.

Background: Obesity is a major risk factor for diabetes and peripheral arterial disease, which frequently leads to lower limb demand ischemia. Skeletal muscle autophagy and mitochondrial biogenesis are important processes for proper oxidative capacity and energy metabolism, which are compromised in diabetes. This study compares autophagy, mitochondrial biogenesis, energy metabolism, and morphology in the hind limbs of obese diabetic mice subjected to demand or sedentary ischemia.

Materials And Methods: Unilateral hind limb demand ischemia was created in a group of diet-induced obese mice after femoral artery ligation and 4 wk of daily exercise. A parallel group of mice underwent femoral artery ligation but remained sedentary for 4 wk. Hind limb muscles were analyzed for markers of autophagy, mitochondrial biogenesis, adenosine triphosphate, and muscle tissue morphology.

Results: At the end of the 4-wk exercise period, demand ischemia increased the autophagy mediator Beclin-1, but it did not alter the autophagy indicator, LC3B-II/I ratio, or markers of mitochondrial biogenesis, optic atrophy/dynamin-related protein. In contrast, exercise significantly increased the level of mitochondrial protein-succinate dehydrogenase subunit-A and reduced adipocyte accumulation and the percentage of centrally nucleated myofibers in the demand ischemia limb. In addition, demand ischemia resulted in decreased uncoupling protein-3 levels without altering muscle adenosine triphosphate or pS473-Akt levels.

Conclusions: Limb demand ischemia markedly decreased adipocyte accumulation and enhanced muscle regeneration in obese mice, but it did not appear to enhance autophagy, mitochondrial biogenesis, energy metabolism, or insulin sensitivity. Future studies aimed at evaluating novel therapies that enhance autophagy and mitochondrial biogenesis in diabetes with peripheral arterial disease are warranted.
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http://dx.doi.org/10.1016/j.jss.2015.04.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4560984PMC
October 2015

Reduced hind limb ischemia-reperfusion injury in Toll-like receptor-4 mutant mice is associated with decreased neutrophil extracellular traps.

J Vasc Surg 2013 Dec 14;58(6):1627-36. Epub 2013 May 14.

Division of Vascular Imaging and Intervention, Harvard Medical School, Massachusetts General Hospital, Boston, Mass.

Objective: Ischemia-reperfusion (IR) injury is a significant problem in the management of patients with acute limb ischemia. Despite rapid restoration of blood flow after technically successful open and endovascular revascularization, complications secondary to IR injury continue to occur and limit clinical success. Our aim was to create a murine model of hind limb IR injury to examine the role of Toll-like receptor-4 (TLR4) and to determine whether inactive TLR4 led to a decrease in the detection of neutrophil extracellular traps (NETs), which are known to be highly thrombogenic and may mediate microvascular injury.

Methods: A calibrated tension tourniquet was applied to unilateral hind limb of wild-type (WT) and TLR4 receptor mutant (TLR4m) mice for 1.5 hours to induce ischemia and then removed to initiate reperfusion. At the end of 48 hours of reperfusion, mice were euthanized and hind limb tissue and serum specimens were collected for analysis. Hematoxylin and eosin-stained sections of hind limb skeletal muscle tissue were examined for fiber injury. For immunohistochemistry, mouse monoclonal antihistone H2A/H2B/DNA complex antibody to detect NETs and rabbit polyclonal antimyeloperoxidase antibody were used to identify infiltrating cells containing myeloperoxidase. Muscle adenosine triphosphate levels, nuclear factor (NF)-κB activity, the α-subunit of inhibitor of NF-κB light polypeptide gene enhancer, poly (adenosine diphosphate-ribose) polymerase activity, and inducible nitric oxide synthase expression were measured. Systemic levels of keratinocyte-derived chemokine, monocyte chemotactic protein-1, and vascular endothelial growth factor in the serum samples were also examined.

Results: IR injury in the hind limb of WT mice demonstrated significant levels of muscle fiber injury, decreased energy substrates, increased NF-κB activation, decreased levels of α-subunit of inhibitor of NF-κB light polypeptide gene enhancer, increased inducible nitric oxide synthase expression, and increased poly (adenosine diphosphate-ribose) polymerase activity levels compared with the TLR4m samples. Additionally, there was marked decrease in the level of neutrophil and monocyte infiltration in the TLR4m mice, which corresponded to similar levels of decreased NET detection in the interstitial space and in microvascular thrombi. In situ nuclease treatment of WT tissue sections significantly diminished the level of NET immunostaining, demonstrating the specificity of the antibody to detect NETs and suggesting a potential role for nuclease treatment in IR injury.

Conclusions: These results suggest a pivotal role for TLR4 in mediating hind limb IR injury and suggest that NETs may contribute to muscle fiber injury.
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http://dx.doi.org/10.1016/j.jvs.2013.02.241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3825746PMC
December 2013

Poly-ADP-ribose-polymerase inhibition ameliorates hind limb ischemia reperfusion injury in a murine model of type 2 diabetes.

Ann Surg 2013 Dec;258(6):1087-95

*Division of Vascular and Endovascular Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, and The University of Tennessee Medical Center, Knoxville, TN †Department of Surgery, The University of Tennessee Graduate School of Medicine, Knoxville, TN ‡Department of Surgery, Sinai Hospital, Baltimore, MD §Division of Vascular Imaging and Intervention, Massachusetts General Hospital, Harvard Medical School, Boston, MA, and The University of Tennessee Medical Center, Knoxville, TN; and ¶Division of Vascular and Endovascular Surgery, Massachusetts General Hospital, Boston, MA.

Introduction: Diabetes is known to increase poly-ADP-ribose-polymerase (PARP) activity and posttranslational poly-ADP-ribosylation of several regulatory proteins involved in inflammation and energy metabolism. These experiments test the hypothesis that PARP inhibition will modulate hind limb ischemia reperfusion (IR) in a mouse model of type-II diabetes and ameliorate the ribosylation and the activity/transnuclear localization of the key glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH).

Methods: db/db mice underwent 1.5 hours of hind limb ischemia followed by 1, 7, or 24 hours of reperfusion. The treatment group received the PARP inhibitor PJ34 (PJ34) over a 24-hour period; the untreated group received Lactated Ringer (LR) at the same time points. IR muscles were analyzed for indices of PARP activity, fiber injury, metabolic activity, inflammation, GAPDH activity/intracellular localization, and poly-ADP-ribosylation of GAPDH.

Results: PARP activity was significantly lower in the PJ34-treated groups than in the Lactated Ringer group at 7 and 24 hours of reperfusion. There was significantly less muscle fiber injury in the PJ34-treated group than in the Lactated Ringer-treated mice at 24 hours of reperfusion. PJ34 lowered levels of select proinflammatory molecules at 7 hours and 24 hours of IR. There were significant increases in metabolic activity only at 24 hours of IR in the PJ34 group, which temporally correlated with increase in GAPDH activity, decreased GAPDH poly-ADP-ribosylation, and nuclear translocation of GAPDH.

Conclusions: PJ34 reduced PARP activity, GAPDH ribosylation, and GAPDH translocation; ameliorated muscle fiber injury; and increased metabolic activity after hind limb IR injury in a murine model of type-II diabetes. PARP inhibition might be a therapeutic strategy after IR in diabetic humans.
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http://dx.doi.org/10.1097/SLA.0b013e31828cced3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3773522PMC
December 2013

Divergent systemic and local inflammatory response to hind limb demand ischemia in wild-type and ApoE-/- mice.

J Surg Res 2013 Aug 15;183(2):952-62. Epub 2013 Mar 15.

Division of Vascular and Endovascular Surgery, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.

Background: We designed studies to determine whether the ApoE-/- phenotype modulates the local skeletal muscle and systemic inflammatory (plasma) responses to lower extremity demand ischemia. The ApoE-/- phenotype is an experimental model for atherosclerosis in humans.

Methods: Aged female ApoE-/- and C57BL6 mice underwent femoral artery ligation, then were divided into sedentary and demand ischemia (exercise) groups on day 14. We assessed baseline and postexercise limb perfusion and hind limb function. On day 14, animals in the demand ischemia group underwent daily treadmill exercise through day 28. Sedentary mice were not exercised. On day 28, we harvested plasma and skeletal muscle from ischemic limbs from sedentary and exercised mice. We assayed muscle for angiogenic and proinflammatory proteins, markers of skeletal muscle regeneration, and evidence of skeletal muscle fiber maturation.

Results: Hind limb ischemia was similar in ApoE-/- and C57 mice before the onset of exercise. Under sedentary conditions, plasma vascular endothelial cell growth factor and interleukin-6, but not keratinocyte chemoattractant factor (KC) or macrophage inflammatory protein-2 (MIP-2), were higher in ApoE (P < 0.0001). After exercise, plasma levels of vascular endothelial cell growth factor, KC, and MIP-2, but not IL-6, were lower in ApoE (P < 0.004). The cytokines KC and MIP-2 in muscle were greater in exercised ApoE-/- mice compared with C57BL6 mice (P = 0.01). Increased poly-ADP-ribose activity and mature muscle regeneration were associated with demand ischemia in the C57BL6 mice, compared with the ApoE-/- mice (P = 0.01).

Conclusions: Demand limb ischemia in the ApoE-/- phenotype exacerbated the expression of select systemic cytokines in plasma and blunted indices of muscle regeneration.
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http://dx.doi.org/10.1016/j.jss.2013.02.042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3713180PMC
August 2013

Differential effect of zoledronic acid on human vascular smooth muscle cells.

J Surg Res 2013 Jun 8;182(2):339-46. Epub 2012 Nov 8.

Division of Vascular and Endovascular Surgery, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.

Introduction: The activation of human vascular smooth muscle cell proliferation, adhesion and migration is essential for intimal hyperplasia formation. These experiments were designed to test whether zoledronic acid (ZA) would modulate indices of human smooth muscle cell activation, exert differential effects on proliferating versus quiescent cells, and determine whether these effects were dependent on GTPase binding proteins prenylation. ZA was chosen for testing in these experiments because it is clinically used in humans with cancer, and has been shown to modulate rat smooth muscle cell proliferation and migration.

Methods: Human aortic smooth muscle cells (HASMC) were cultured under either proliferating or growth arrest (quiescent) conditions in the presence or absence of ZA for 48 hours, whereupon the effect of ZA on HASMC proliferation, cellular viability, metabolic activity, and membrane integrity were compared. In addition, the effect of ZA on adhesion and migration were assessed in proliferating cells. The effect of increased concentration of ZA on the mevalonate pathway and genomic/cellular stress related poly-adenosine diphosphate ribose polymerase enzyme activity were assessed using the relative prenylation of Rap-1A/B protein and the formation of poly adenosine diphosphate-ribosylated protein, respectively.

Results: There was a dose dependent inhibition of cellular proliferation, adhesion and migration following ZA treatment. ZA treatment decreased indices of cellular viability and significantly increased membrane injury in proliferating versus quiescent cells. This was correlated with the appearance of unprenylated Rap-1A protein and dose dependent down regulation of activity.

Conclusions: These data suggest that ZA is effective in inhibiting HASMC proliferation, adhesion, and migration, which coincide with the appearance of unprenylated RAP-1A/B protein, thereby suggesting that the mevalonate pathway may play a role in the inhibition of HASMC activation.
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http://dx.doi.org/10.1016/j.jss.2012.10.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3618863PMC
June 2013

Inhalation of carbon monoxide reduces skeletal muscle injury after hind limb ischemia-reperfusion injury in mice.

Am J Surg 2012 Apr;203(4):488-95

Division of Vascular and Endovascular Surgery, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.

Background: The purpose of this study was to determine if inhaled carbon monoxide (CO) can ameliorate skeletal muscle injury, modulate endogenous heme oxygenase-1 expression, and improve indexes of tissue integrity and inflammation after hind limb ischemia reperfusion.

Methods: C57BL6 mice inhaling CO (250 ppm) or room air were subjected to 1.5 hours of ischemia followed by limb reperfusion for either 3 or 6 hours (total treatment time, 4.5 or 7.5 h). After the initial period of reperfusion, all mice breathed only room air until 24 hours after the onset of ischemia. Mice were killed at either the end of CO treatment or at 24 hours' reperfusion. Skeletal muscle was subjected to histologic and biochemical analysis.

Results: CO treatment for 7.5 hours protected skeletal muscle from histologic and structural evidence of skeletal muscle injury. Serum and tissue cytokines were reduced significantly (P < .05) in mice treated with CO for 7.5 hours. Tubulin, heme oxygenase, and adenosine triphosphate levels were higher in CO-treated mice.

Conclusions: Inhaled CO protected muscle from structural injury and energy depletion after ischemia reperfusion.
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http://dx.doi.org/10.1016/j.amjsurg.2011.05.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3315834PMC
April 2012

The effects of systemic hypothermia on a murine model of thoracic aortic ischemia reperfusion.

J Vasc Surg 2010 Aug 11;52(2):435-43. Epub 2010 Jun 11.

Division of Vascular and Endovascular Surgery, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Mass, USA.

Introduction: Hypothermia is widely used to mediate ischemia-reperfusion injury associated with repair of the thoracoabdominal aorta. Experiments were designed in a murine model of thoracic aortic ischemia-reperfusion (TAR) to evaluate the effect of moderate systemic hypothermia on neurologic function, spinal cord morphology, and indices of inflammation in critical organs.

Methods: C57BL/6 mice were subjected to TAR under hypothermic (34 degrees C) or normothermic (38 degrees C) conditions, followed by 24 or 48 hours of normothermic reperfusion. Neurologic functions were assessed during reperfusion. Spinal cords were examined at 24 and 48 hours after reperfusion, and the degree of injury qualified by counting the number of viable motor neurons within the anterior horns. Keratinocyte chemokine, interleukin-6, and myeloperoxidase levels were measured from lung, liver, and kidney at 24 and 48 hours.

Results: Normothermic TAR resulted in a dense neurologic deficit in all mice throughout the reperfusion period. Mice subjected to TAR under hypothermic conditions had transient, mild neurologic deficit during the initial periods of reperfusion. Between 24 and 48 hours, delayed paralysis developed in half of these mice, whereas the other half remained neurologically intact. Spinal cord histology showed a graded degree of injury that correlated with neurologic function. There was no correlation between markers of inflammation in various organs and neurologic outcomes following TAR.

Conclusion: Systemic moderate hypothermia was protective against immediate paralysis after TAR in all cases and was associated with delayed paralysis in 50% of mice. This study suggests that delayed-onset paralysis may be the result of a local insult, rather than a systemic inflammatory event, precipitating spinal cord injury.
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http://dx.doi.org/10.1016/j.jvs.2010.03.021DOI Listing
August 2010

Postischemic poly (ADP-ribose) polymerase (PARP) inhibition reduces ischemia reperfusion injury in a hind-limb ischemia model.

Surgery 2010 Jul 4;148(1):110-8. Epub 2010 Feb 4.

Division of Vascular and Endovascular Surgery, Massachusetts General Hospital, Boston, MA 02114, USA.

Background: Several experiments were designed to determine whether the systemic, postischemic administration of PJ34,which is a poly-adenosine diphosphate (ADP)-ribose polymerase inhibitor, decreased tissue injury and inflammation after hind-limb ischemia reperfusion (I/R).

Methods: C57BL6 mouse limbs were subjected to 1.5 h ischemia followed by 24-h reperfusion. The treatment group (PJ) received intraperitoneal PJ34 (30 mg/kg) immediately before reperfusion, as well as 15 min and 2 h into reperfusion. The control group (CG) received lactated Ringer's alone at the same time intervals as PJ34 administration. The skeletal muscle levels of adenosine triphosphate (ATP), macrophage inflammatory protein-2 (MIP-2), keratinocyte derived chemokine (KC), and myeloperoxidase (MPO) were measured. Quantitative measurement of skeletal muscle tissue injury was assessed by microscopic analysis of fiber injury.

Results: ATP levels were higher in limbs of PJ versus CG mice (absolute ATP: 4.7 +/- 0.35 vs 2.3 +/- 0.15-ng/mg tissue, P = .002). The levels of MIP-2, KC, and MPO were lower in PJ versus CG mice (MIP-2: 1.4 +/- 0.34 vs 3.67 +/- 0.67-pg/mg protein, P = .014; KC: 4.97 +/- 0.97 vs 12.65 +/- 3.05-pg/mg protein, P = .037; MPO: 46.27 +/- 10.53 vs 107.34 +/- 13.58-ng/mg protein, P = .008). Muscle fiber injury was markedly reduced in PJ versus CG mice (4.25 +/- 1.9% vs 22.68 +/- 3.0% total fibers, P = .0004).

Conclusion: Systemic postischemic administration of PJ34 preserved skeletal muscle energy levels, decreased inflammatory markers, and preserved tissue viability post-I/R. These results support PARP inhibition as a viable treatment for skeletal muscle I/R in a clinically relevant post hoc scenario.
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http://dx.doi.org/10.1016/j.surg.2009.12.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886175PMC
July 2010

The characteristics of integrins expression in decidualized human endometrial stromal cell induced by 8-Br-cAMP in in vitro.

Exp Mol Med 2002 Jul;34(3):194-200

Department of Obstetrics and Gynecology, College of Medicine, Hanyang University, Seoul, Korea.

Integrins are heterodimeric glycoproteins that have been found to undergo dynamic temporal and spatial changes in the endometrium during the menstrual cycle and in early pregnancy. Specificity of integrins is known to be different in human endometrial stromal cells and decidual cells. These shifts of integrins suggested to play an important role in embryo implantation and can be modulated by progesterone, cAMP derivatives, and cytokines. The mechanisms of decidualization and its precise physiological role are still not clearly understood and in vitro systems could provide an alternative that overcomes limitations of studying such complex biological phenomena in vivo at the time of implantation. This study was undertaken to establish an in vitro model system for human decidualization using 8-bromo-cAMP and to investigate the characteristics of stromal integrin expression in vitro by 8-Br-cAMP. Endometrial stromal cells were isolated and cultured, and then were induced to decidualize by 0.5 mM 8-Br-cAMP for 15 days. Immunofluorescence staining and flow cytometric analyses of the integrin subunits (alpha1, alpha4, alpha5, alpha6, beta1 and alphavbeta3) were performed at day 9. In the presence of 8-Br-cAMP, the staining intensity of alphavbeta3 was significantly higher than control and measurements for alpha1, alpha4, alpha5, alpha6, and beta1 were similar. Immunofluorescent localization of the integrins reflected the differences obtained from the flow cytometric analyses described above. In summary, the expression of alphavbeta3 integrin increased in stromal cells in vitro decidualized by 8-Br-cAMP and this up-regulation of alphavbeta3 integrin expression during decidualization might influence on human implantation.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626578PMC
http://dx.doi.org/10.1038/emm.2002.28DOI Listing
July 2002