Limits...
Novel Sensor-Enabled Ex Vivo Bioreactor: A New Approach towards Physiological Parameters and Porcine Artery Viability.

Mundargi R, Venkataraman D, Kumar S, Mogal V, Ortiz R, Loo J, Venkatraman S, Steele T - Biomed Res Int (2015)

Bottom Line: The aim of the present work is to design and construct an ex vivo bioreactor system to assess the real time viability of vascular tissue.Histological evaluations with hematoxylin and eosin and Masson's trichrome staining show intact endothelium with fresh porcine tissue whereas tissues after incubation in ex vivo bioreactor studies indicate denuded endothelium supporting the viability results from real time measurements.Hence, this novel viability sensor-enabled ex vivo bioreactor acts as model to mimic in vivo system and record vascular responses to biopharmaceutical molecules and biomedical devices.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798.

ABSTRACT
The aim of the present work is to design and construct an ex vivo bioreactor system to assess the real time viability of vascular tissue. Porcine carotid artery as a model tissue was used in the ex vivo bioreactor setup to monitor its viability under physiological conditions such as oxygen, pressure, temperature, and flow. The real time tissue viability was evaluated by monitoring tissue metabolism through a fluorescent indicator "resorufin." Our ex vivo bioreactor allows real time monitoring of tissue responses along with physiological conditions. These ex vivo parameters were vital in determining the tissue viability in sensor-enabled bioreactor and our initial investigations suggest that, porcine tissue viability is considerably affected by high shear forces and low oxygen levels. Histological evaluations with hematoxylin and eosin and Masson's trichrome staining show intact endothelium with fresh porcine tissue whereas tissues after incubation in ex vivo bioreactor studies indicate denuded endothelium supporting the viability results from real time measurements. Hence, this novel viability sensor-enabled ex vivo bioreactor acts as model to mimic in vivo system and record vascular responses to biopharmaceutical molecules and biomedical devices.

No MeSH data available.


Related in: MedlinePlus

Representative graph showing effect of shear stress on tissue viability. Real time tissue viability monitored after tissues stored for 24 h (32 dynes/cm2) and 48 h (8 dynes/cm2) to demonstrate ex vivo bioreactor functionality to record variations in tissue responses at given conditions.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4644552&req=5

fig4: Representative graph showing effect of shear stress on tissue viability. Real time tissue viability monitored after tissues stored for 24 h (32 dynes/cm2) and 48 h (8 dynes/cm2) to demonstrate ex vivo bioreactor functionality to record variations in tissue responses at given conditions.

Mentions: To study the real time tissue response, the harvested artery was fixed to the bioreactor and circulating media from bioreactor were aligned to flow via flow cells situated in fluorimeter. The florescence intensity of resorufin as cell viability indicator was measured at specific time intervals (Figure 2(a)). In the present bioreactor system resazurin (50 μM) converts to fluorescent resorufin in the cell mitochondria; the real time fluorescent values recorded during ex vivo perfusion were computed to slope values for control (silicon tube) and tissue. Figure 4 depicts the tissue response at different shear stress in the ex vivo perfusion system and approximate vascular wall shear stress at artery wall was determined by using Hagen-Poiseuille approximation by computing flow rate, vessel diameter, and viscosity of the medium [21]. The real time response from the tissue at shear stress of 8 dynes/cm2 and 32 dynes/cm2 indicates effect of shear stress induced by the perfusion system. In case of control (silicon tube) the real time measurements show constant fluorescent values due to absence of any metabolic activity. In case of relatively higher vascular shear stress (32 dynes/cm2) the tissue viability dropped higher compared to low vascular stress of 8 dynes/cm2 and this could lead to denudation of endothelium [23]. Thus, initiation of SMC death as well as luminal and abluminal progression of cell death could suggest the damage to the endothelium initiating chain of reactions leading to cell death [16]. Hence, the physiological parameters along with shear stress, tissue harvest time are vital in deciding the rate of tissue metabolism and viability in ex vivo perfusion system [19].


Novel Sensor-Enabled Ex Vivo Bioreactor: A New Approach towards Physiological Parameters and Porcine Artery Viability.

Mundargi R, Venkataraman D, Kumar S, Mogal V, Ortiz R, Loo J, Venkatraman S, Steele T - Biomed Res Int (2015)

Representative graph showing effect of shear stress on tissue viability. Real time tissue viability monitored after tissues stored for 24 h (32 dynes/cm2) and 48 h (8 dynes/cm2) to demonstrate ex vivo bioreactor functionality to record variations in tissue responses at given conditions.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644552&req=5

fig4: Representative graph showing effect of shear stress on tissue viability. Real time tissue viability monitored after tissues stored for 24 h (32 dynes/cm2) and 48 h (8 dynes/cm2) to demonstrate ex vivo bioreactor functionality to record variations in tissue responses at given conditions.
Mentions: To study the real time tissue response, the harvested artery was fixed to the bioreactor and circulating media from bioreactor were aligned to flow via flow cells situated in fluorimeter. The florescence intensity of resorufin as cell viability indicator was measured at specific time intervals (Figure 2(a)). In the present bioreactor system resazurin (50 μM) converts to fluorescent resorufin in the cell mitochondria; the real time fluorescent values recorded during ex vivo perfusion were computed to slope values for control (silicon tube) and tissue. Figure 4 depicts the tissue response at different shear stress in the ex vivo perfusion system and approximate vascular wall shear stress at artery wall was determined by using Hagen-Poiseuille approximation by computing flow rate, vessel diameter, and viscosity of the medium [21]. The real time response from the tissue at shear stress of 8 dynes/cm2 and 32 dynes/cm2 indicates effect of shear stress induced by the perfusion system. In case of control (silicon tube) the real time measurements show constant fluorescent values due to absence of any metabolic activity. In case of relatively higher vascular shear stress (32 dynes/cm2) the tissue viability dropped higher compared to low vascular stress of 8 dynes/cm2 and this could lead to denudation of endothelium [23]. Thus, initiation of SMC death as well as luminal and abluminal progression of cell death could suggest the damage to the endothelium initiating chain of reactions leading to cell death [16]. Hence, the physiological parameters along with shear stress, tissue harvest time are vital in deciding the rate of tissue metabolism and viability in ex vivo perfusion system [19].

Bottom Line: The aim of the present work is to design and construct an ex vivo bioreactor system to assess the real time viability of vascular tissue.Histological evaluations with hematoxylin and eosin and Masson's trichrome staining show intact endothelium with fresh porcine tissue whereas tissues after incubation in ex vivo bioreactor studies indicate denuded endothelium supporting the viability results from real time measurements.Hence, this novel viability sensor-enabled ex vivo bioreactor acts as model to mimic in vivo system and record vascular responses to biopharmaceutical molecules and biomedical devices.

View Article: PubMed Central - PubMed

Affiliation: School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798.

ABSTRACT
The aim of the present work is to design and construct an ex vivo bioreactor system to assess the real time viability of vascular tissue. Porcine carotid artery as a model tissue was used in the ex vivo bioreactor setup to monitor its viability under physiological conditions such as oxygen, pressure, temperature, and flow. The real time tissue viability was evaluated by monitoring tissue metabolism through a fluorescent indicator "resorufin." Our ex vivo bioreactor allows real time monitoring of tissue responses along with physiological conditions. These ex vivo parameters were vital in determining the tissue viability in sensor-enabled bioreactor and our initial investigations suggest that, porcine tissue viability is considerably affected by high shear forces and low oxygen levels. Histological evaluations with hematoxylin and eosin and Masson's trichrome staining show intact endothelium with fresh porcine tissue whereas tissues after incubation in ex vivo bioreactor studies indicate denuded endothelium supporting the viability results from real time measurements. Hence, this novel viability sensor-enabled ex vivo bioreactor acts as model to mimic in vivo system and record vascular responses to biopharmaceutical molecules and biomedical devices.

No MeSH data available.


Related in: MedlinePlus