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Research Interests

Regulation of liver microcirculation: Role of stress-inducible vasoactive mediators (endothelin, nitric oxide synthase, heme oxygenase) in altering vascular responsiveness in the liver following oxidative or inflammatory stress. Mechanisms of control of sinusoid perfusion by hepatic Clemens 2014 squarestellate cells, especially related to components of phenotypic transformation in response to injury.

Hepatic metabolic response to infection. Mechanisms of altered carbohydrate metabolism during sepsis, especially related to differentiation between inflammation-induced changes in gene expression and perfusion supply/demand ratio as mediators of decreased gluconeogenesis.

Application of imaging techniques to biological research. In vivo video microscopy for study of liver microcirculation; application of quantitative fluorescence techniques to monitoring of cellular processes in intact organs or in vivo.

Engineered liver support systems: Bioengineering Research Partnership BRP page
Professional Experience

Research Scientist, Department of Surgery,Yale University, 1981-86

Assistant Professor, Departments of Surgery and Physiology, Johns Hopkins School of Medicine, 1986-91

Associate Professor, Departments of Surgery and Physiology, Johns Hopkins School of Medicine, 1992-96

Robert Garrett Scholar, Johns Hopkins School of Medicine, 1986-96

Director of Pediatric Surgery Research, Johns Hopkins School of Medicine, 1986-96

Professor and Chair, Department of Biological Sciences, UNC Charlotte, 1996-2005

Professor of Biological Sciences, UNC Charlotte 2005 – present

Vice President and Chief Scientific Officer, HepatoSys Inc


Education

B.S., Physical Therapy; St. Louis University, 1975

Ph.D., Physiology; St. Louis University, 1979

Postdoctoral Fellowship, Physiology and Metabolism; Yale University, 1980-81
Courses Taught (*offered for Graduate Credit)

BIOL 3273 Animal Physiology

*BIOL 6104/8104 Integrated Systems Physiology

*BIOL 8201 PhD Seminar

*BIOL 6050 Advanced Human Physiology

*BIOL 8000 Hypothesis Testing

*BIOL 4000 / 5000 Cardiovascular Physiology
Selected Recent Publications

  1. Christoph Sponholz1 Q2 , Katja Matthes1 , Dina Rupp1 , Wolf Backaus1 , Sebastian Klammt2 , Diana Karailieva3,4, 7 Astrid Bauschke5 , Utz Settmacher5 , Matthias Kohl6 , Mark G. Clemens4,7,8, Steffen Mitzner9,10, Michael Bauer1,4 8 and Andreas Kortgen1,4*. Molecular adsorbent recirculating system and single-pass albumin dialysis in liver failure – a prospective, randomised crossover study. Critical Care (in press).
  2. Deepak Gopalakrishna1, Samantha Pennington1, Amel Karaa1 and Mark G.Clemens1,2 ET-1 stimulates superoxide production by eNOS following exposure of vascular endothelial cells to endotoxin. Shock (in press).
  3. Adrian T. Press, Luisa Ungelenk, Alexandra C. Rinkenauer, Marko Gröger, Frank Lehmann, Alexander Mosig, Ulrich S. Schubert, Mark G. Clemens, Michael Bauer. A new fluorescent dye for cell tracing and mitochondrial imaging in vitro and in vivo.  Journal of Biophotonics 2015 Nov 13. doi: 10.1002/jbio.201500190. [Epub ahead of print]  PMID: 26563981
  4. Press AT, Traeger A, Pietsch C, Mosig A, Wagner M, Clemens MG, Jbeily N, Koch N, Gottschaldt M, Bézière N, Ermolayev V, Ntziachristos V, Popp J, Kessels MM, Qualmann B, Schubert US, Bauer M. Cell type-specific delivery of short interfering RNAs by dye-functionalised theranostic nanoparticles. Nat Commun. 2014 Dec 3;5:5565. doi: 10.1038/ncomms6565. PMID: 25470305
  5. Sendi H, Mehrab-Mohseni M, Foureau DM, Ghosh S, Walling TL, Steuerwald N, Zamor PJ, Kaplan KJ, Jacobs C, Ahrens WA, Russo MW, Clemens MG, Schrum LW, Bonkovsky HL. miR-122 decreases HCV entry into hepatocytes through binding to the 3′ UTR of OCLN mRNA. Liver Int. 2014 Oct 10. doi: 10.1111/liv.12698. [Epub ahead of print] PMID: 25302477
  6. Kwok W, Clemens MG. Rho-kinase activation contributes to Lps-induced impairment of endothelial nitric oxide synthase activation by endothelin-1 in cultured hepatic sinusoidal endothelial cells. Shock. 2014 Dec;42(6):554-61. doi: 10.1097/SHK.0000000000000252. PMID: 25243430
  7. Norris EJ,Feilen NNguyen NHCulberson CRShin MCFish MClemens MG. Hydrogen sulfide modulates sinusoidal constriction and contributes to hepatic microcirculatory dysfunction during endotoxemia. Am J Physiol Gastrointest Liver Physiol. 2013 Jun 15;304(12):G1070-8
  8. Norris EJ, Larion S, Culberson CR,Clemens MG.Hydrogen sulfide differentially affects the hepatic vasculature in response to phenylephrine and endothelin 1 during endotoxemia. Shock. 2013 Feb;39(2):168-75
  9. Norris EJ, Culberson CR, Narasimhan S, Clemens MG. The Liver as a Central Regulator of Hydrogen Sulfide.  Shock. 2011 Sep;36(3):242-50
  10. Nguyen N, Keller S, Norris E, Huynh T, Clemens M, Shin M. Tracking Colliding Cells in vivo Microscopy. IEEE Trans Biomed Eng. 2011 May 31. [Epub ahead of print]
  11. Day SA, Lakner AM, Moore CC, Yen MH, Clemens MG, Wu ES, Schrum LW. Opioid-like compound exerts anti-fibrotic activity via decreased hepatic stellate cell activation and inflammation.  Biochem Pharmacol. 2011 Apr 15;81(8):996-1003.
  12. Kwok W, Clemens MG. Targeted mutation of Cav-1 alleviates the effect of endotoxin in the inhibition of ET-1-mediated eNOS activation in the liver. 2010 Apr;33(4):392-8
  13. Kwok W, Lee SH, Culberson C, Korneszczuk K, Clemens MG. Caveolin-1 mediates endotoxin inhibition of endothelin-1-induced endothelial nitric oxide synthase activity in liver sinusoidal endothelial cells.  Am J Physiol Gastrointest Liver Physiol. 2009 297(5):G930-9
  14. Kamoun WS, Schmugge SJ, Kraftchick JP, Clemens MG, Shin MC. Liver microcirculation analysis by red blood cell motion modeling in intravital microscopy images.  IEEE Trans Biomed Eng. 2008 Jan;55(1):162-70.
  15. Lee SH, Culberson C, Korneszczuk K, Clemens MG. Differential Mechanisms of Hepatic Vascular Dysregulation with Mild vs Moderate Ischemia / Reperfusion.  Am J Physiol Gastrointest Liver Physiol. 2008 294(5):G1219-26.
  16. Lee SH, Coger RN and Clemens MG. Antioxidant functionality in hepatocytes using enhanced collagen extracellular matrix under different oxygen tensions.  Tissue Engineering 2006 Oct;12(10):2825-34.
  17. Zinchenko YS, Schrum LW, Clemens M, Coger RN. Hepatocyte and kupffer cells co-cultured on micropatterned surfaces to optimize hepatocyte function.
    Tissue Eng. 2006 Apr;12(4):751-61
  18. Karaa A, Kamoun WS, Xu H, Zhang J, Clemens MG. Differential effects of oxidative stress on hepatic endothelial and Kupffer cell eicosanoid release in response to endothelin-1. 2006 Sep;13(6):457-66.
  19. Merkel SM, Kamoun W,  Karaa A,  Korneszczuk K, . Schrum LW and Mark G. Clemens.  LPS Inhibits Endothelin-1-Mediated eNOS Translocation to the Cell Membrane in Sinusoidal Endothelial Cells.  Microcirculation 12: 433-442, 2005.
  20. Keller SA, Paxian M, Ashburn JH , Clemens MG, and Toan Huynh.  Kupffer Cell Ablation Improves Hepatic Microcirculation after Trauma and Sepsis.   Trauma 58(4):740-9 2005.
  21. Keller SA, Paxian M, Lee SM, Clemens MG, and Toan Huynh. Kupffer Cell Ablation Attenuates Cyclooxygenase-2 Expression after Trauma and Sepsis.  J Surg Res 124(1): 126-33, 2005.
  22. Kamoun WS, Shin MC, Karaa A, Clemens MG. Quantification of hepatic microcirculation heterogeneity of perfusion: Effects of endothelin-1. Microvasc Res. 2005 May;69(3):180-6.
  23. Xu H, Korneszczuk K, Karaa A ,  Lin T, Clemens MG, and Jian X. Zhang Thromboxane A2 from Kupffer cells contributes to the hyperresponsiveness of hepatic portal circulation to endothelin-1 in endotoxemic rats. Am J Physiol Gastrointest Liver Physiol 288: G277-G283, 2005
  24. Jain S, Lee CY, Baicu S, Duncan H, Xu H, Jones JW Jr, Clemens MG, Brassil J, Taylor MJ, Brockbank KG. Hepatic function in hypothermically stored porcine livers: comparison of hypothermic machine perfusion vs cold storage. Transplant Proc. 37(1):340-1, 2005.
  25. Xu H, Zhang JX, Jones JW, Southard JH, Clemens MG, Lee CY. Hypothermic machine perfusion of rat livers preserves endothelial cell function.  Transplant Proc.37(1):335-7, 2005.
  26. Karaa A, Kamoun W and Clemens MG. Oxidative stress disrupts nitric oxide synthase activation in liver endothelial cells.  Free Radical Biology and Medicine 39(10):1320-31, 2005
  27. Kamoun WS, Shin MC., Keller S, Karaa A, Huynh T, Clemens MG. Induction of Biphasic Changes in Perfusion Heterogeneity of Rat Liver Following Sequential Stress in Vivo.  Shock 24(4):324-331, 2005.
  28. Mark G. CLEMENS, Walid KAMOUN, Amel KARAA, and Sandra MERKEL. Altered caveolae-associated signalling in liver sinusoidal endothelial cells following inflammation.  Microcirculation Annual 21: 7-10, 2005
  29. Karaa A, Kamoun WS, Clemens MG. Chronic Ethanol Sensitizes the Liver to Endotoxin via Effects on Endothelial Nitric Oxide Synthase Regulation.  Shock  24(5):447-54, 2005
  30. Paxian M,. Keller S, Cross B, Huynh T, and Mark G. Clemens.  High resolution visualization of oxygen distribution in the liver in vivo.  Am J Physiol Gastrointest Liver Physiol.  Jan; 286(1): G37-44, 2004.
  31. Rensing H, Bauer I, Zhang JX, Paxian M, Pannen BH, Yokoyama Y, Clemens MG, Bauer M. Endothelin-1 and heme oxygenase-1 as modulators of sinusoidal tone in the stress-exposed rat liver.  Hepatology 2002 Dec;36(6):1453-65

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