scholarly journals Role of 1,25-dihydroxycholecalciferol in growth-plate cartilage: inhibition of terminal differentiation of chondrocytes in vitro and in vivo.

1990 ◽  
Vol 87 (17) ◽  
pp. 6522-6526 ◽  
Author(s):  
Y. Kato ◽  
A. Shimazu ◽  
M. Iwamoto ◽  
K. Nakashima ◽  
T. Koike ◽  
...  
1989 ◽  
Vol 257 (2) ◽  
pp. 399-405 ◽  
Author(s):  
R Négrel ◽  
D Gaillard ◽  
G Ailhaud

The terminal differentiation of Ob1771 pre-adipose cells induced by arachidonic acid in serum-free hormone-supplemented medium containing insulin, transferrin, growth hormone, tri-iodothyronine and fetuin (5F medium) was strongly diminished in the presence of inhibitors of prostaglandin synthesis, namely aspirin or indomethacin. Carbaprostacyclin, a stable analogue of prostacyclin (prostaglandin I2) known to be synthesized by pre-adipocytes and adipocytes, behaved as an efficient activator of cyclic AMP production and was able, when added to 5F medium, to mimic the adipogenic effect of arachidonic acid. Prostaglandins E2, F2 alpha and D2, unable to affect the cyclic AMP production, failed to substitute for carbaprostacyclin. However, prostaglandin F2 alpha, which is another metabolite of arachidonic acid in pre-adipose and adipose cells, able to promote inositol phospholipid breakdown and protein kinase C activation, potentiated the adipogenic effect of carbaprostacyclin. In addition, carbaprostacyclin enhanced both a limited proliferation and terminal differentiation of adipose precursor cells isolated from rodent and human adipose tissues maintained in primary culture. These results demonstrate the critical role of prostacyclin and prostaglandin F2 alpha on adipose conversion in vitro and suggest a paracrine/autocrine role of both prostanoids in the development of adipose tissue in vivo.


2007 ◽  
Vol 93 (3) ◽  
pp. 1039-1050 ◽  
Author(s):  
Rebecca M. Williams ◽  
Warren R. Zipfel ◽  
Michelle L. Tinsley ◽  
Cornelia E. Farnum

2021 ◽  
pp. 088532822199989
Author(s):  
Christopher Erickson ◽  
Michael Stager ◽  
Michael Riederer ◽  
Karin A Payne ◽  
Melissa Krebs

The growth plate is a cartilage tissue near the ends of children’s long bones and is responsible for bone growth. Injury to the growth plate can result in the formation of a ‘bony bar’ which can span the growth plate and result in bone growth abnormalities in children. Biomaterials such as chitosan microgels could be a potential treatment for growth plate injuries due to their chondrogenic properties, which can be enhanced through loading with biologics. They are commonly fabricated via an emulsion method, which involves solvent rinses that are cytotoxic. Here, we present a high throughput, non-cytotoxic, non-emulsion-based method to fabricate chitosan–genipin microgels. Chitosan was crosslinked with genipin to form a hydrogel network, and then pressed through a syringe filter using mesh with various pore sizes to produce a range of microgel particle sizes. The microgels were then loaded with chemokines and growth factors and their release was studied in vitro. To assess the applicability of the microgels for growth plate cartilage regeneration, they were injected into a rat growth plate injury. They led to increased cartilage repair tissue and were fully degraded by 28 days in vivo. This work demonstrates that chitosan microgels can be fabricated without solvent rinses and demonstrates their potential for the treatment of growth plate injuries.


2019 ◽  
Vol 133 (3) ◽  
pp. 425-441 ◽  
Author(s):  
Yinlan Hu ◽  
Guoqing Jin ◽  
Bing Li ◽  
Yanmei Chen ◽  
Lintao Zhong ◽  
...  

Abstract MiRNAs regulate the cardiomyocyte (CM) cell cycle at the post-transcriptional level, affect cell proliferation, and intervene in harmed CM repair post-injury. The present study was undertaken to characterize the role of let-7i-5p in the processes of CM cell cycle and proliferation and to reveal the mechanisms thereof. In the present study, we used real-time qPCR (RT-qPCR) to determine the up-regulated let-7i-5p in CMs during the postnatal switch from proliferation to terminal differentiation and further validated the role of let-7i-5p by loss- and gain-of-function of let-7i-5p in CMs in vitro and in vivo. We found that the overexpression of let-7i-5p inhibited CM proliferation, whereas the suppression of let-7i-5p significantly facilitated CM proliferation. E2F2 and CCND2 were identified as the targets of let-7i-5p, mediating its effect in regulating the cell cycle of CMs. Supperession of let-7i-5p promoted the recovery of heart function post-myocardial infarction by enhancing E2F2 and CCND2. Collectively, our results revealed that let-7i-5p is involved in the regulation of the CM cell cycle and further impacts proliferation, which may offer a new potential therapeutic strategy for cardiac repair after ischemic injury.


2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.


Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
HM Lee ◽  
TG Ahn ◽  
CW Kim ◽  
HJ An
Keyword(s):  

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.


1971 ◽  
Vol 66 (3) ◽  
pp. 558-576 ◽  
Author(s):  
Gerald Burke

ABSTRACT A long-acting thyroid stimulator (LATS), distinct from pituitary thyrotrophin (TSH), is found in the serum of some patients with Graves' disease. Despite the marked physico-chemical and immunologic differences between the two stimulators, both in vivo and in vitro studies indicate that LATS and TSH act on the same thyroidal site(s) and that such stimulation does not require penetration of the thyroid cell. Although resorption of colloid and secretion of thyroid hormone are early responses to both TSH and LATS, available evidence reveals no basic metabolic pathway which must be activated by these hormones in order for iodination reactions to occur. Cyclic 3′, 5′-AMP appears to mediate TSH and LATS effects on iodination reactions but the role of this compound in activating thyroidal intermediary metabolism is less clear. Based on the evidence reviewed herein, it is suggested that the primary site of action of thyroid stimulators is at the cell membrane and that beyond the(se) primary control site(s), there exists a multifaceted regulatory system for thyroid hormonogenesis and cell growth.


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