A simple method to determine nanogram levels of 4-hydroxyproline in biological tissues

Jamall, Ijaz S.; Finelli, Vincent N.; Hee, Shane S. Que

doi:10.1016/0003-2697(81)90261-x

Cited by 495 publications

(283 citation statements)

References 9 publications

Supporting

Mentioning

279

Contrasting

Unclassified

Order By: Relevance

“…Our results did not correlate well with the work of Beljaar et al (30), who showed only a trivial accumulation of (M6P) x -HSA in the liver when x was equal to 10 or below, but 59.2% as the hepatic uptake when x was equal to 28. This discrepancy is possibly due to the following two reasons: i) we used M6P-BSA, since it was also shown 52.6% accumulated in the liver for (M6P) 21 -BSA (30); ii) in our case, M6P-BSA was further conjugated with TFO, which is a polyanion with molecular weight of >8000Da, and must have some influence on the biodistribution of M6P-BSA. Apparently, there was a saturation in the hepatic uptake of M6P-BSA-TFO, since (M6P) 20 -BSA-TFO and (M6P) 27 -BSA-TFO were not significantly different in the hepatic uptake (Fig.…”

Section: Discussionmentioning

confidence: 85%

Receptor-Mediated Hepatic Uptake of M6P−BSA-Conjugated Triplex-Forming Oligonucleotides in Rats

Cheng

Guntaka

et al. 2006

Bioconjugate Chem.

View full text Add to dashboard Cite

Excessive production of extracellular matrix, predominantly type I collagen results in liver fibrosis. Earlier we synthesized mannose 6-phosphate-bovine serum albumin (M6P-BSA) and conjugated to the type I collagen specific triplex forming oligonucleotide (TFO) for its enhanced delivery to hepatic stellate cells (HSCs), which is the principle liver fibrogenic cell. In this report, we demonstrate a time-dependent cellular uptake of M6P-BSA-33 P-TFO by HSC-T6 cells. Both cellular uptake and nuclear deposition of M6P-BSA-33 P-TFO were significantly higher than those of 33 P-TFO, leading to enhanced inhibition of type I collagen transcription. Following systemic administration into rats, hepatic accumulation of M6P-BSA-33 P-TFO increased from 55% to 68% with the number of M6P per BSA from 14 to 27. Unlike 33 P-TFO, there was no significant decrease in the hepatic uptake of (M6P) 20 -BSA-33 P-TFO in fibrotic rats. Prior administration of excess M6P-BSA decreased the hepatic uptake of (M6P) 20 -BSA-33 P-TFO from 66% to 40% in normal rats, and from 60% to 15% in fibrotic rats, suggesting M6P/insulin-like growth factor II (M6P/IGF-II) receptor-mediated endocytosis of M6P-BSA-33 P-TFO by HSCs. Almost 82% of the total liver uptake in fibrotic rats was contributed by HSCs. In conclusion, by conjugation with M6P-BSA, the TFO could be potentially used for the treatment of liver fibrosis.

show abstract

Section: Discussionmentioning

confidence: 85%

Receptor-Mediated Hepatic Uptake of M6P−BSA-Conjugated Triplex-Forming Oligonucleotides in Rats

Cheng

Guntaka

et al. 2006

Bioconjugate Chem.

View full text Add to dashboard Cite

show abstract

“…Hepatic hydroxyproline content was determined photometrically in liver hydrolysate as previously described. 26 Quantitative RT-PCR. RNA was isolated from 30 mg of shock-frozen liver tissue with the RNeasy Mini Kit (Qiagen, Hilden, Germany) according to the manufacturer's guidelines.…”

Section: Methodsmentioning

confidence: 99%

Atorvastatin lowers portal pressure in cirrhotic rats by inhibition of RhoA/Rho-kinase and activation of endothelial nitric oxide synthase

Trebicka

Hennenberg

Laleman³

et al. 2007

Hepatology

279

338

View full text Add to dashboard Cite

In cirrhosis, increased RhoA/Rho-kinase signaling and decreased nitric oxide (NO) availability contribute to increased intrahepatic resistance and portal hypertension. Hepatic stellate cells (HSCs) regulate intrahepatic resistance. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) inhibit synthesis of isoprenoids, which are necessary for membrane translocation and activation of small GTPases like RhoA and Ras. Activated RhoA leads to Rho-kinase activation and NO synthase inhibition. We therefore investigated the effects of atorvastatin in cirrhotic rats and isolated HSCs. Rats with secondary biliary cirrhosis (bile duct ligation, BDL) were treated with atorvastatin (15 mg/kg per day for 7 days) or remained untreated. Hemodynamic parameters were determined in vivo (colored microspheres). Intrahepatic resistance was investigated in in situ perfused livers. Expression and phosphorylation of proteins were analyzed by RT-PCR and immunoblots. Three-dimensional stress-relaxed collagen lattice contractions of HSCs were performed after incubation with atorvastatin. Atorvastatin reduced portal pressure without affecting mean arterial pressure in vivo. This was associated with a reduction in intrahepatic resistance and reduced responsiveness of in situ-perfused cirrhotic livers to methoxamine. Furthermore, atorvastatin reduced the contraction of activated HSCs in a 3-dimensional stress-relaxed collagen lattice. In cirrhotic livers, atorvastatin significantly decreased Rho-kinase activity (moesin phosphorylation) without affecting expression of RhoA, Rho-kinase and Ras. In activated HSCs, atorvastatin inhibited the membrane association of RhoA and Ras. Furthermore, in BDL rats, atorvastatin significantly increased hepatic endothelial nitric oxide synthase (eNOS) mRNA and protein levels, phospho-eNOS, nitrite/nitrate, and the activity of the NO effector protein kinase G (PKG). Conclusion: In cirrhotic rats, atorvastatin inhibits hepatic RhoA/Rhokinase signaling and activates the NO/PKG-pathway. This lowers intrahepatic resistance, resulting in decreased portal pressure. Statins might represent a therapeutic option for portal hypertension in cirrhosis. (HEPATOLOGY 2007;46:242-253.)

show abstract

“…Fibrosis was also assessed biochemically by the quantification of the collagen-specific amino-acid hydroxyproline as described by Jamall et al 12 The liver concentration of hydroxyproline was determined from a standard curve generated from known quantities of hydroxyproline.…”

Section: Histological and Biochemical Assessment Of Liver Fibrosismentioning

confidence: 99%

Reversal of liver fibrosis by the antagonism of endocannabinoid CB1 receptor in a rat model of CCl4-induced advanced cirrhosis

Giannone

Baldassarre

Domenicali

et al. 2012

Laboratory Investigation

View full text Add to dashboard Cite

The endocannabinoid system is involved in the pathogenesis of liver fibrosis. Although many substances have been proved to reduce fibrosis in experimental models of chronic liver injury, most of them appear to be effective only if given as a prophylactic or early treatment. This study aimed to explore the effect of pharmacological antagonism of the endocannabinoid cannabinoid type 1 (CB1) receptor started after the stage of full-blown cirrhosis had been reached. Wistar-Han rats with carbon tetrachloride (CCl 4 )-induced cirrhosis were randomized to receive the CB1 receptor antagonist Rimonabant (10 mg/kg/day) or the vehicle for 2 weeks. Age-matched healthy rats served as controls. Liver fibrosis was assessed using Sirius red staining, hydroxyproline concentration and a-smooth muscle actin expression. Hepatic gene expression of mediators of fibrogenesis and inflammation were evaluated by real-time PCR. We also assessed the hepatic expression of CB1 and CB2 receptors and that of the enzymes implicated in the endocannabinoid metabolism. Fibrosis was significantly reduced in rats treated with Rimonabant compared with rats receiving the vehicle. CB1 receptor antagonism limited the gene upregulation of fibrogenic and inflammatory mediators occurring in untreated cirrhotic rats. CB1 and CB2 receptor expression was increased in cirrhotic animals. Interestingly, pharmacological CB1 receptor antagonism was associated with a further induction of the CB2 receptor expression. Regression of fibrosis can be achieved by pharmacological blockade of the CB1 receptor even when started in an advanced stage of the disease. This effect is associated with the suppression of pro-fibrogenic and inflammatory mediators and may have been indirectly favoured by the induction of CB2 receptor expression.

show abstract

A simple method to determine nanogram levels of 4-hydroxyproline in biological tissues

Cited by 495 publications

References 9 publications

Receptor-Mediated Hepatic Uptake of M6P−BSA-Conjugated Triplex-Forming Oligonucleotides in Rats

Receptor-Mediated Hepatic Uptake of M6P−BSA-Conjugated Triplex-Forming Oligonucleotides in Rats

Atorvastatin lowers portal pressure in cirrhotic rats by inhibition of RhoA/Rho-kinase and activation of endothelial nitric oxide synthase

Reversal of liver fibrosis by the antagonism of endocannabinoid CB1 receptor in a rat model of CCl4-induced advanced cirrhosis

Contact Info

Product

Resources

About