Hypermethylated SFRP2 and WIF-1 genes in fecal DNA are novel and promising molecular biomarkers that have great diagnostic potential for early CRC.

Stool-based DNA testing may be useful for noninvasively diagnosing colorectal tumours and SFRP2 methylation is a promising marker that has great potential in early CRC diagnosis.

This is an open access article under the terms of the Creat ive Commo ns Attri butio n-NonCo mmerc ial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.Abbreviations: ACD, acid citrate dextrose; aCSF, artificial cerebrospinal fluids; ATP, adenosine triphosphate; BBB, blood-brain barrier; BCRP, breast cancer resistance protein; C csf , concentration in cerebrospinal fluids; CL, clearance; C m,blood/brain , unbound concentration in blood/brain measured by microdialysis; CNS, central nervous system; CSF, cerebrospinal fluids; C ss , steady-state concentration; C u,brain , unbound concentration in brain measured by equilibrium dialysis; DMEM, Dulbecco's Modified Eagle's Medium; DMSO, dimethyl sulfoxide; EDTA-K 2 , ethylenediaminetetraacetic acid dipotassium; ER, efflux ratio; FBS, Fetal bovine serum; f u,brain , unbound fraction in brain; HBSS, Hank's balanced salt solution;HPLC/MS/MS, high-performance liquid chromatography combined with tandem mass spectrometry; HP-β-CD, hydroxypropyl-β-cyclodextrin; IACUC, institutional animal care and use committee; ISF, interstitial fluids; K p,uu,brain , ratio of unbound brain concentration to unbound blood AbstractIn clinical pharmacology, the free drug hypothesis has been widely applied in the interpretation of the relationship between pharmacokinetics and pharmacodynamics (PK/ PD). The free drug hypothesis assumes that the unbound drug concentration in blood is the same as that in the site of action at steady state. The objective of this study is to demonstrate whether the free drug hypothesis is universally applicable for all drugs.The unbound concentrations of the 18 compounds in blood and in brain interstitial fluids (ISF) at steady state following constant intravenous infusion were simultaneously monitored up to 6 hours via in vivo microdialysis technique. Based on the permeability and efflux ratio (ER), the test compounds can be divided into two classes.Class I includes the compounds with good membrane permeability that are not substrates of efflux transporters (eg, P-gp, BCRP, and MRPs), whereas Class II includes the compounds that are substrates of efflux transporters. The steady-state unbound drug concentrations in blood, brain, and CSF are quantitatively very similar for Class I compounds, whereas the steady-state unbound concentrations in the brain and CSF are significantly lower than those in blood for Class II compounds. These results strongly suggest that the free drug hypothesis is not universal for all drugs but is only applicable for drugs with good permeability that are not substrates of efflux transporters. K E Y W O R D SBBB, efflux transporter, microdialysis, permeability, unbound concentration

Salt-sensitive hypertension is associated with severe organ damage. Generating oxygen radicals is an integral component of salt-induced kidney damage, and activated leukocytes are important in oxygen radical biosynthesis. We hypothesized that a high-salt diet causes the upregulation of immune-related mechanisms, thereby contributing to the susceptibility of Dahl salt-sensitive rats to hypertensive kidney damage. For verifying the hypothesis, we investigated leukocytes adhering to retinal vessels when Dahl salt-sensitive rats were challenged with a high-salt (8% NaCl) diet using acridine orange fluoroscopy and a scanning laser ophthalmoscope. The high-salt diet increased leukocyte adhesion after 3 days and was associated with a significant increase in mRNA biosynthesis of monocyte chemotactic protein-1 and intercellular adhesion molecule-1 (ICAM-1) -related molecules in the kidney. Losartan treatment did not affect increased leukocyte adhesion during the early, pre-hypertensive phase of high salt loading; however, losartan attenuated the adhesion of leukocytes during the hypertensive stage. Moreover, the inhibition of leukocyte adhesion in the pre-hypertensive stage by anti-CD18 antibodies decreased tethering of leukocytes and was associated with the attenuation of functional and morphological kidney damage without affecting blood pressure elevation. In conclusion, a high-salt challenge rapidly increased leukocyte adhesion through the over-expression of ICAM-1. Increased leukocyte adhesion in the pre-hypertensive stage is responsible for subsequent kidney damage in Dahl salt-sensitive rats. Immune system involvement may be a key component that initiates kidney damage in a genetic model of salt-induced hypertension.

Dahl salt-sensitive (Dahl S) rats are prone to salt-dependent hypertension with severe organ damage, including stroke, cardiac failure and renal insufficiency. The mechanism for this susceptibility to kidney injury has not been elucidated. The present study proposed that an upregulation of intracellular signaling of angiotensin II (Ang-II) is responsible for the susceptibility to hypertensive kidney injury in Dahl S rats. Spontaneously hypertensive rats exhibited higher systolic blood pressure (SBP) and lower kidney damage than Dahl S rats fed a high-salt diet for 2 weeks. Ang-II infusion for 4 weeks significantly increased SBP in Dahl S and Dahl salt-resistant (Dahl R) rats fed a low-salt diet. The increase in SBP in Dahl S rats was associated with significant kidney injury with greater glomerular sclerosis (P<0.001). The expression of regulatory protein of Gαq signaling-2 (RGS2) mRNA in the aortic walls in response to Ang-II infusion was lower in Dahl S than Dahl R rats (P<0.05). Ang-II significantly increased RGS2 mRNA in the aorta in Dahl R rats, but the response was apparently blunted in Dahl S rats. These results suggest that Dahl S rats exhibit a blunted RGS2 response to Ang-II, and this blunted response may be partially responsible for the susceptibility to renal injury in Dahl S rats.