RESUMO
An established method for the cryopreservation of human femoral arteries for subsequent transplantation as allografts has been studied with particular attention to preservation of smooth muscle and endothelium. Human femoral arteries (HFAs) were harvested from multi-organ donors. Two groups were established; a control group of unfrozen HFAs and a group of cryopreserved HFAs. Cryopreservation was performed using RPMI solution containing dimethyl sulfoxide and the rate of cooling was 1 degrees C/min to -40 degrees C and faster thereafter until -150 degrees C was reached. The contraction and relaxation responses of unfrozen and frozen/thawed arteries were assessed by measurement of the isometric force generated by the HFAs in an organ bath. After thawing (warming was at 15 degrees C/min) the maximal contractile response to noradrenaline was 43% of the response of unfrozen HFAs. The endothelium-independent response to sodium nitroprusside was not altered, whereas the endothelium-dependent relaxation response to acetylcholine was slightly altered. The cryopreservation method used provided limited preservation of the contractility of human femoral arteries, and good preservation of both endothelium-independent and endothelium-dependent relaxation responses.
Assuntos
Criopreservação/métodos , Artéria Femoral , Acetilcolina/farmacologia , Crioprotetores , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/lesões , Endotélio Vascular/fisiopatologia , Artéria Femoral/efeitos dos fármacos , Artéria Femoral/lesões , Artéria Femoral/fisiopatologia , Humanos , Técnicas In Vitro , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/lesões , Músculo Liso Vascular/fisiopatologia , Nitroprussiato/farmacologia , Norepinefrina/farmacologia , Soluções , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
An established method for cryopreservation that might preserve the vascular and endothelial responses of human femoral arteries (HFAs) to be transplanted as allografts was studied. HFAs were harvested from multiorgan donors and stored at 4 degrees C in saline solution before cryostorage. Thirty HFA rings were isolated and randomly assigned to one control group of unfrozen HFAs (eight rings) and one group of cryopreserved HFAs (22 rings). Cryopreservation was performed in RPMI solution containing dimethylsulfoxide (DMSO) and the rate of cooling was -1 degrees C/min until -40 degrees C and faster rates until -150 degrees C was reached. The contractile and relaxant responses of unfrozen and frozen/thawed arteries were assessed in organ bath by measurement of isometric force generated by the HFAs. After thawing, the maximal contractile responses to the contracting agonist tested (noradrenaline) were in the range of 43% of the responses in unfrozen HFAs. The endothelium-independent responses to sodium nitroprusside were not altered whereas the endothelium-dependent relaxant responses to acetylcholine were weakly altered. The cryopreservation method used provided a limited preservation of contractility of HFAs, a good preservation of the endothelium-independent relaxant responses, and a good preservation of endothelium-dependent relaxation. It is possible that further refinements of the cryopreservation protocol, such as a slower rate of cooling and a more controlled stepwise addition of DMSO, might allow better post-thaw functional recovery.
Assuntos
Criopreservação , Artéria Femoral , Preservação de Tecido , Acetilcolina/farmacologia , Crioprotetores , Dimetil Sulfóxido , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Feminino , Artéria Femoral/efeitos dos fármacos , Artéria Femoral/fisiologia , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Norepinefrina/farmacologia , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
Several in vitro studies have demonstrated diminished post-thaw functional activity. Therefore, the aim of this study was to investigate the consequences of thawing and storage method used on the post-thaw functional activity of cryopreserved pig aortas with the aim of adjusting the freezing and thawing protocol so that the vascular segments are preserved in the best possible state, maintaining structure and functionality so that they can later be transplanted with success. In vitro responses of frozen, thawed pig aortas were used to investigate the functional activity after thawing at 15 degrees C and 100 degrees C/min and after storage in gas or liquid phase of liquid nitrogen. Cryopreservation was performed in RPMI 1640 medium + 10% dimethylsulfoxide and the rate of cooling was -1 degrees C/min, until -150 degrees C was reached. After thawing the maximal contractile responses to all the contracting agonists tested (KCl, noradrenaline) were in the ranges of 13-27% compared with the responses in unfrozen pig aortas. Contractile responses were slightly better when thawing was performed at 15 degrees C/min compared with 100 degrees C/min. The endothelium independent relaxant responses to sodium nitroprusside were reduced ( P < 0.05). Cryostorage of pig arteries also resulted in a loss of the endothelium-dependent relaxant response to acetylcholine. The cryopreservation method used provided a limited preservation of pig aorta contractibility, a reduction of the endothelium independent relaxant responses, and no apparent preservation of the endothelium-dependent relaxation. It is possible that further refinements of the cryopreservation protocol might allow better post-thaw functional recovery of pig aortas.
Assuntos
Aorta Abdominal , Criopreservação , Preservação de Tecido , Animais , Aorta Abdominal/efeitos dos fármacos , Aorta Abdominal/fisiologia , Crioprotetores , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Técnicas In Vitro , Nitroprussiato/farmacologia , Norepinefrina/farmacologia , Cloreto de Potássio/farmacologia , Suínos , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
We evaluated the impact of standard cryopreservation on functional properties of human aortic homografts. From seven human donors, the thoracic descending aorta was obtained. Effects of cryopreservation on contractibility and endothelium function were tested. After cryopreservation no endothelium-dependent or endothelium-independent relaxation was found and the contractibility was strongly affected. Arteries showed no function and loss of endothelial integrity after cryopreservation and thawing.