scholarly journals Pretreatment with melatonin improves ovarian tissue cryopreservation for transplantation.

2020 ◽  
Author(s):  
Marcos Eiji Shiroma ◽  
Luciana Lamarão Damous ◽  
Fernanda Pereira Cotrim ◽  
Cristiane Lima Roa ◽  
José Cipolla-Neto ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Von Willebrand Factor ◽  
Caspase 3 ◽  
Collagen Type ◽  
Female Rats ◽  
Corpora Lutea ◽  
Ki 67 ◽  
Ovarian Graft ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Background: Melatonin has anti-inflammatory and antioxidative actions at the mitochondrial level. This indole may protect the ovarian graft during the cryopreservation process. Therefore, our study aimed to determine whether melatonin pretreatment improves rat ovarian graft quality. Methods: Twenty female rats were allocated to two study groups of ten animals each: 1) control group: ovaries cryopreserved using the standard protocol; and 2) melatonin group: ovaries cryopreserved in a medium with melatonin. Following 24-h freezing, whole ovaries underwent autologous and avascular transplants with retroperitoneal placement. After postoperative (PO) day 15, daily vaginal smears were obtained for estrous cycle characterization. Between PO days 30 and 35, animals were euthanized and ovarian grafts were recovered for histological and immunohistochemical (Ki-67, cleaved caspase-3, TUNEL, von Willebrand factor, estrogen, and progesterone receptors) analysis. The ovaries of the three remaining rats from each group were studied immediately after thawing to assess cryopreservation effects. The ANOVA and the Tukey tests were used, and the rejection level of the null hypothesis was set at 0.05 or 5% (p<0.05).Results: Melatonin promoted faster restart of the estrous cycle and increased the expression of mature follicles, collagen type I, von Willebrand factor, Ki-67, and cleaved caspase-3 on corpora lutea and estrogen receptors in the ovaries. There was a reduction in apoptosis by TUNEL on follicles, corpora lutea, and collagen type III. Conclusion: Melatonin may promote the quality of ovarian grafts through the evaluated parameters. Reproductive function enhancement could be further studied.

scholarly journals Pretreatment with melatonin improves ovarian tissue cryopreservation for transplantation

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Marcos Eiji Shiroma ◽  
Luciana Lamarão Damous ◽  
Fernanda Pereira Cotrim ◽  
Cristiane Lima Roa ◽  
José Cipolla-Neto ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Von Willebrand Factor ◽  
Caspase 3 ◽  
Collagen Type ◽  
Female Rats ◽  
Ovarian Tissue Cryopreservation ◽  
Corpora Lutea ◽  
Ki 67 ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Backgroud Melatonin has anti-inflammatory and antioxidative actions at the mitochondrial level. This indole-containing molecule may protect ovarian grafts during the process of cryopreservation. Therefore, we aimed to determine whether melatonin pretreatment improves rat ovarian graft quality. Methods Twenty-six female rats were allocated to two study groups of thirteen animals each: 1) control group: ovaries cryopreserved using the standard protocol; and 2) melatonin group: ovaries cryopreserved in a medium with melatonin. Ten rats of each group were submitted to 24-h freezing, and whole ovaries autologous and avascular transplantation with retroperitoneal placement. After postoperative (PO) day 15, daily vaginal smears were obtained for estrous cycle characterization. Between PO days 30 and 35, the animals were euthanized and ovarian grafts were recovered for histological and immunohistochemical (Ki-67, cleaved caspase-3, TUNEL, von Willebrand factor, estrogen, and progesterone receptors) analyses. The ovaries of the three remaining rats from each group were studied immediately after thawing to assess the effects of cryopreservation. ANOVA and Tukey’s tests were used and the rejection level of the null hypothesis was set at 0.05 or 5% (p < 0.05). Results Melatonin promoted faster restart of the estrous cycle and increased the expression of mature follicles, collagen type I, von Willebrand factor, Ki-67, and cleaved caspase-3 on corpora lutea and estrogen receptors in the ovaries as compared to control. There was a reduction in apoptosis by TUNEL on follicles, corpora lutea, and collagen type III. Conclusion Based on the evaluated parameters, melatonin may promote the quality of ovarian grafts. Reproductive function enhancement should be further studied.

PRIMARY BINDING SITE OF VON WILLEBRAND FACTOR IN THE SUBENDOTHELIUM WHICH MEDIATES PLATELET ADHESION IS NOT COLLAGEN

1987 ◽  
Author(s):  
Philip G de Groot ◽  
Jan A van Mourik ◽  
Jan J Sixma
Keyword(s):  
Monoclonal Antibody ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type I ◽  
Extracellular Matrices ◽  
Type I ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

We have studies the binding of von Willebrand factor (vWF) to extracellular matrices of endothelial cells and smooth muscle cells and to the vessel wall of human umbilical arteries in relation to its function in supporting platelet adhesion at high shear rates. CLB-RAg 38, a monoclonal antibody directed against vWF inhibits the binding of 125I-vWF extracellular matrices completely. The binding of 125I-vWF to subendothelium is not inhibited, because there are many different binding sites. CLB-RAg 38 inhibits platelet adhesion to extracellular matrices and subendothelium, in sofar as it is dependent on plasma vWF. CLB-RAg 38 has no effect on adhesion depending on vWF already bound to the matrix or subendothelium. CLB-RAg 38 does not inhibit binding of vWF to collagen type I and type III. Another monoclonal antibody against vWF, CLB-RAg 201, completely inhibits binding of vWF to collagen type I and type III. CLB-RAg 201 does not inhibit binding of 125I-vWF ot the extracellular matrices. CLB-RAg 201 partly inhibits platelet adhesion but this inhibition is also present when the adhesion depends on vWF already present in matrix or subendothelium, indicating that CLB-RAg 201 also inhibits the adhesion of platelets directly, this in contrast to CLB-RAg 38. The epitopes for CLB-RAg 201 and 38 were found on different tryptic fragments of vWF. These data indicate that vWF binds to subendothelium and to matrices of cultured cells by mechanism that is different from binding to collagen.

scholarly journals Platelet adhesion to collagen in healthy volunteers is influenced by variation of both α2β1 density and von Willebrand factor

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1433-1437 ◽  
Author(s):  
Mark Roest ◽  
Jan J. Sixma ◽  
Ya-Ping Wu ◽  
Martin J. W. Ijsseldijk ◽  
Mariëlle Tempelman ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Normal Subjects ◽  
Collagen Type Iv ◽  
Collagen Types ◽  
Platelet Surface ◽  
Type Iv ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Platelet thrombus formation on collagen is initiated by platelet GPIb interaction with von Willebrand factor (vWF) bound to collagen, followed by firm attachment of the platelet to collagen by the integrin α2β1. Platelet and plasma vWF levels and α2β1 density on the platelet surface are highly variable among normal subjects; however, little is known about the consequences of this variability on platelet adhesion to collagen. A population of 32 normal subjects was studied to evaluate the relation between genetic and phenotypic variations of α2β1 density on the platelet surface, plasma vWF levels, platelet vWF levels, and adenosine diphosphate and adenosine triphosphate concentrations on the one hand and platelet adhesion to collagen under flow on the other hand. Platelet adhesion to collagen types I and III under flow was correlated with plasma levels of vWF (r2 = 0.45 and 0.42, respectively) and α2β1 density on the platelet surface (r2 = 0.35 and 0.17, not significant). Platelet adhesion to collagen type IV under flow was significantly correlated with platelet vWF levels (r2 = 0.34) and α2β1 density on the platelet surface (r2 = 0.42). Platelet adhesion to collagen types I and III depends on both plasma levels of vWF and α2β1 density on the platelet surface, whereas platelet adhesion to collagen type IV is mediated by both platelet vWF levels and α2β1 density on the platelet surface.

scholarly journals Platelet adhesion to collagen in healthy volunteers is influenced by variation of both α2β1 density and von Willebrand factor

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1433-1437 ◽  
Author(s):  
Mark Roest ◽  
Jan J. Sixma ◽  
Ya-Ping Wu ◽  
Martin J. W. Ijsseldijk ◽  
Mariëlle Tempelman ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Normal Subjects ◽  
Collagen Type Iv ◽  
Collagen Types ◽  
Platelet Surface ◽  
Type Iv ◽  
Von Willebrand ◽  
Willebrand Factor

Platelet thrombus formation on collagen is initiated by platelet GPIb interaction with von Willebrand factor (vWF) bound to collagen, followed by firm attachment of the platelet to collagen by the integrin α2β1. Platelet and plasma vWF levels and α2β1 density on the platelet surface are highly variable among normal subjects; however, little is known about the consequences of this variability on platelet adhesion to collagen. A population of 32 normal subjects was studied to evaluate the relation between genetic and phenotypic variations of α2β1 density on the platelet surface, plasma vWF levels, platelet vWF levels, and adenosine diphosphate and adenosine triphosphate concentrations on the one hand and platelet adhesion to collagen under flow on the other hand. Platelet adhesion to collagen types I and III under flow was correlated with plasma levels of vWF (r2 = 0.45 and 0.42, respectively) and α2β1 density on the platelet surface (r2 = 0.35 and 0.17, not significant). Platelet adhesion to collagen type IV under flow was significantly correlated with platelet vWF levels (r2 = 0.34) and α2β1 density on the platelet surface (r2 = 0.42). Platelet adhesion to collagen types I and III depends on both plasma levels of vWF and α2β1 density on the platelet surface, whereas platelet adhesion to collagen type IV is mediated by both platelet vWF levels and α2β1 density on the platelet surface.

scholarly journals Platelet Adhesion to Multimeric and Dimeric von Willebrand Factor and to Collagen Type III Preincubated With von Willebrand Factor

1996 ◽  
Vol 16 (5) ◽  
pp. 611-620 ◽  
Author(s):  
Ya-Ping Wu ◽  
Hans H.F.I. van Breugel ◽  
Hanneke Lankhof ◽  
Robert J. Wise ◽  
Robert I. Handin ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type Iii ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

scholarly journals Microparticles adhere to collagen type I, fibrinogen, von Willebrand factor and surface immobilised platelets at physiological shear rates

2007 ◽  
Vol 138 (4) ◽  
pp. 527-533 ◽  
Author(s):  
J. F. W. Keuren ◽  
E. J. P Magdeleyns ◽  
A. Bennaghmouch ◽  
E. M. Bevers ◽  
J. Curvers ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Collagen Type ◽  
Collagen Type I ◽  
Type I ◽  
Shear Rates ◽  
Von Willebrand ◽  
Willebrand Factor

A3 Domain Is Essential for Interaction of von Willebrand Factor with Collagen Type III

1996 ◽  
Vol 75 (06) ◽  
pp. 950-958 ◽  
Author(s):  
Hanneke L Lankhof ◽  
Maggy van Hoeij ◽  
Marion E Schiphorst ◽  
Madelon Bracke ◽  
Ya-Ping Wu ◽  
...  
Keyword(s):  
Binding Site ◽  
Von Willebrand Factor ◽  
Binding Sites ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Collagen Type Iii ◽  
Collagen Binding ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

Summaryvon Willebrand factor (vWF) mediates platelet adhesion at sites of vascular damage. It acts as a bridge between receptors on platelets and collagens present in the connective tissue. Two collagen binding sites have been identified on the A1 and A3 domain of the vWF subunit. To study the functional importance of these binding sites, we have made two deletion mutants that lack the A1 domain (residues 478-716; ΔA1-vWF; Sixma et al. Eur. J. Biochem. 196,369,1991 [1]) or the A3 domain (residues 910-1113; ΔA3-vWF). After transfection in baby hamster kidney cells overexpressing furin, the mutants were processed and secreted efficiently. Ristocetin or botrocetin induced platelet binding was normal for ΔA3-vWF as was binding to heparin and factor VIII. As reported by Sixma et al. (1) ΔAl-vWF still binds to collagen type III, indicating that the A3 domain is sufficient for the interaction. In the current study, we investigated the binding of ΔA3-vWF to collagen type III. When preincubated on collagen type III it did not support platelet adhesion under flow conditions, whereas it was able to support platelet adhesion when coated directly to a glass surface. The binding of 125I-ΔA3-vWF to collagen was specific but maximal binding was about 40 times less compared to 125I-vWF. When added at 25 times excess, ΔA3-vWF did not compete with 125I-vWF for binding to collagen type III, whereas ΔAl-vWF did. The binding of 125I-ΔA3-vWF could be blocked by excess unlabeled vWF but not by ΔA1-vWF. In conclusion, we demonstrate that the A3 domain in vWF contains the major collagen binding site. The major binding site present on the A3 domain and the minor site present on A1 bind to different sites on collagen.

scholarly journals Functional Studies on Platelet Adhesion With Recombinant von Willebrand Factor Type 2B Mutants R543Q and R543W Under Conditions of Flow

Blood ◽  
1997 ◽  
Vol 89 (8) ◽  
pp. 2766-2772 ◽  
Author(s):  
Hanneke Lankhof ◽  
Conchi Damas ◽  
Marion E. Schiphorst ◽  
Martin J.W. IJsseldijk ◽  
Madelon Bracke ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Von Willebrand Factor ◽  
Platelet Adhesion ◽  
Collagen Type ◽  
Cell Culture Supernatant ◽  
Collagen Type Iii ◽  
Type Iii ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Type 2B von Willebrand disease (vWD) is characterized by the absence of the very high molecular weight von Willebrand factor (vWF ) multimers from plasma, which is caused by spontaneous binding to platelet receptor glycoprotein Ib (GPIb). We studied two mutations in the A1 domain at position 543 in which arginine (R) was replaced by glutamine (Q) or tryptophan (W), respectively. Both mutations were previously identified in vWD type 2B patients. The mutations R543Q and R543W were cloned into a eukaryotic expression vector and subsequently transfected in baby hamster kidney cells overexpressing furin (fur-BHK). Stable cell lines were established by which the mutants were secreted in the cell culture supernatant. The subunit composition and multimeric structure of R543Q and R543W were similar to wild-type (WT) vWF. The mutants showed a spontaneous binding to GPIb. R543Q and R543W showed normal binding to collagen type III or heparin. Both mutants supported platelet adhesion under conditions of flow, usually when preincubated on a collagen type III surface. A low dose (2.5% of the concentration present in normal pooled plasma) of recombinant R543Q or R543W added to normal whole blood inhibited platelet adhesion to collagen type III. No inhibition was found when vWF was used as an adhesive surface. These results indicate that point mutations identified in vWD type 2B cause bleeding symptoms by two mechanisms: (1) the mutants cause platelet aggregation, which in vivo is followed by removal of the aggregates leading to the loss of high molecular weight multimers and thrombocytopenia, (2) on binding to circulating platelets the mutants block platelet adhesion. Relatively few molecules are required for the latter effect.

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