Compared with SFA intake, n-6 PUFAs reduce liver fat and modestly improve metabolic status, without weight loss. A high n-6 PUFA intake does not cause any signs of inflammation or oxidative stress. Downregulation of PCSK9 could be a novel mechanism behind the cholesterol-lowering effects of PUFAs. This trial was registered at clinicaltrials.gov as NCT01038102.

Objective-To gain insight into the function of proprotein convertase subtilisin kexin type 9 (PCSK9) in humans by establishing whether circulating levels are influenced by diurnal, dietary, and hormonal changes. Methods and Results-We monitored circulating PCSK9 in a set of dynamic human experiments and could show that serum PCSK9 levels display a diurnal rhythm that closely parallels that of cholesterol synthesis, measured as serum lathosterol. In contrast to these marked diurnal changes in cholesterol metabolism, serum low-density lipoprotein (LDL) cholesterol levels remained stable during the diurnal cycle. Depletion of liver cholesterol by treatment with the bile acid-binding resin, cholestyramine, abolished the diurnal rhythms of both PCSK9 and lathosterol. Fasting (Ͼ18 hours) strongly reduced circulating PCSK9 and lathosterol levels, whereas serum LDL levels remained unchanged. Growth hormone, known to be increased during fasting in humans, reduced circulating PCSK9 in parallel to LDL cholesterol levels. Conclusion-Throughout the day, and in response to fasting and cholesterol depletion, circulating PCSK9 displays marked variation, presumably related to oscillations in hepatic cholesterol that modify its activity in parallel with cholesterol synthesis. In addition to this sterol-mediated regulation, additional effects on LDL receptors may be mediated by hormones directly influencing PCSK9. Key Words: circulating PCSK9 Ⅲ cholesterol synthesis Ⅲ LDL cholesterol Ⅲ diurnal rhythm Ⅲ growth hormone Ⅲ cholesterol-lowering drugs Ⅲ lipoproteins G enetic variants of proprotein convertase subtilisin kexin type 9 (PCSK9) influence plasma low-density lipoprotein (LDL) cholesterol in humans, accounting for both hypercholesterolemia and hypocholesterolemia and altered coronary risk. 1,2 PCSK9 modulates the number of LDL receptors (LDLRs) by triggering the degradation of LDLRs. 3 Gain-offunction mutations in the PCSK9 gene produce a phenotype of familial hypercholesterolemia, 1 whereas loss-of-function mutations reduce plasma LDL cholesterol levels. 2 Circulating PCSK9 is largely derived from the liver, 4,5 and plasma levels relate to the hepatic expression of PCSK9. 6 -9 It is still unclear to what extent PCSK9 is physiologically regulated and if such regulation may influence plasma LDL cholesterol levels in humans. Novel therapies aiming at lowering serum LDL cholesterol by interfering with PCSK9 activity are under development. 10 Fasting plasma levels of PCSK9 correlate positively with LDL cholesterol levels in healthy and diabetic patients 7,[11][12][13][14] ; however, in the most extensive study, 7 with Ͼ3000 subjects, PCSK9 levels only predicted 7% of the variation in LDL cholesterol. In animals, the hepatic gene expression of PCSK9 is partly under hormonal control: treatment with glucagon or high-dose estrogen reduces PCSK9 mRNA and increases the number of LDLRs, 15 whereas insulin 15,16 and growth hormone (GH) 17 both increase PCSK9 mRNA levels in rat liver.The gene expressions of PCSK9, the LDLR and 3-hydroxy-3-...

— The influence of cigarette smoking on the vascular reaction during plaque induced gingivitis was studied in humans for 28 days. Sixteen healthy dental students, 8 smokers and 8 non‐smokers, aged 19–42 yr, volunteered for the experiment. A numerical method was used for the evaluation of the vascular reaction. With the aid of stereophotographs changes in the number of gingival vessels were followed during the experiment. It was found that the number of vessels identified increased over time during the experiment in both smokers and non‐smokers. However, in spite of the fact that the plaque accumulation rate was equal, the vascular reaction was less pronounced in smokers. At the end of the experiment after 28 days the intensity of the vascular reaction in smokers was only 50% of that observed in non‐smokers. The difference was statistically significant at the P‐level of 0.05. One week after termination of the experiment and reinstitution of oral hygiene the number of gingival vessels equaled the pre‐experimental values in both groups. The results indicate that the vascular reaction associated with plaque induced gingivitis is suppressed in smokers.