Examining the central effects of chronic stressful social isolation on rats.

Stress-related disorders are extremely complex and current treatment strategies have limitations. The present study investigated alternative pathological mechanisms using a combination of multiple environmental approaches with biochemical and molecular tools. The aim of the present study was to evaluate blood-brain-barrier (BBB) integrity in socially manipulated animal housing conditions. Multiple environmentally-related models were employed in the current study. The main model proposed (chronically isolated rats) was biochemically validated using the level of peripheral corticosterone. The current study examined and compared the mRNA levels of certain inflammatory and BBB markers in the hippocampal tissue of chronically isolated rats, including claudin-5 (cldn5) and tight junction protein (tjp). Animals were divided into four groups: i) Standard housed rats (controls); ii) chronically isolated rats; iii) control rats treated with fluoxetine, which is a standard selective serotonin reuptake inhibitor; and iv) isolated rats treated with fluoxetine. To further examine the effect of environmental conditions on BBB markers, the current study assessed BBB markers in enriched environmental (EE) housing and short-term isolation conditions. The results demonstrated a significant increase in cldn5 and tjp levels in the chronically isolated group. Despite some anomalous results, alterations in mRNA levels were further confirmed in EE housing conditions compared with chronically isolated rats. This trend was also observed in rats subjected to short-term isolation compared with paired controls. Additionally, levels of IL-6, an inflammatory marker associated with neuroinflammation, were markedly increased in the isolated group. However, treatment with fluoxetine treatment reversed these effects. The results indicated that BBB integrity may be compromised in stress-related disorders, highlighting a need for further functional studies on the kinetics of BBB in stress-related models.

Triglyceride-Rich Lipoproteins Modulate the Distribution and Extravasation of Ly6C/Gr1(low) Monocytes.

Monocytes are heterogeneous effector cells involved in the maintenance and restoration of tissue integrity. However, their response to hyperlipidemia remains poorly understood. Here, we report that in the presence of elevated levels of triglyceride-rich lipoproteins, induced by administration of poloxamer 407, the blood numbers of non-classical Ly6C/Gr1(low) monocytes drop, while the number of bone marrow progenitors remains similar. We observed an increased crawling and retention of the Gr1(low) monocytes at the endothelial interface and a marked accumulation of CD68(+) macrophages in several organs. Hypertriglyceridemia was accompanied by an increased expression of tissue, and plasma CCL4 and blood Gr1(low) monocyte depletion involved a pertussis-toxin-sensitive receptor axis. Collectively, these findings demonstrate that a triglyceride-rich environment can alter blood monocyte distribution, promoting the extravasation of Gr1(low) cells. The behavior of these cells in response to dyslipidemia highlights the significant impact that high levels of triglyceride-rich lipoproteins may have on innate immune cells.

The coagulopathy of liver disease: does vitamin K help?

Vitamin K is frequently administered in cirrhotic patients to correct their coagulopathy, but evidence for such practice is lacking. We aimed to assess whether vitamin K administration increases the levels of the vitamin K-dependent factor VII (FVII), protein C, and protein S in patients with different stages of liver dysfunction. Eighty-nine patients were recruited into four groups: group 1 [hepatitis B virus (HBV) inactive carriers, n = 23]; group 2 [chronic HBV and hepatitis C virus (HCV) hepatitis, n = 21]; group 3 (cirrhosis, n = 24); group 4 (hepatocellular carcinoma, n = 21); and a healthy control group (n = 39). A single dose of 10 mg of vitamin K1 was administered subcutaneously to all patients. Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, FVII, protein C, total and free protein S, and proteins induced by vitamin K absence (PIVKA)-II (des-gamma-carboxy prothrombin) were measured at baseline and 72 h after vitamin K administration. There was progressive increment in baseline PIVKA-II, and decrements in fibrinogen, FVII, protein C, and protein S across study groups (P < 0.0001). Compared to baseline, vitamin K administration did not affect the measured parameters, whereas TT showed no reduction in any of the groups. Protein C levels declined in group 2, whereas FVII, total and free protein S did not increase in any group, for all parameters. Vitamin K therapy does not cause significant improvements in the majority of coagulation parameters and hence does not seem to be routinely indicated in patients with liver disease.