Association of serum lipids and abnormal lipid score with cancer risk: a population-based prospective study

BACKGROUND

Serum lipid levels are associated with cancer risk. However, there still have uncertainties about the single and combined effects of low lipid levels on cancer risk.

METHODS

A prospective cohort study of 33,773 adults in Shanghai between 2016 and 2017 was conducted. Total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels were measured. Cox proportional hazard models were used to assess the association of single and combined lipids with overall, lung, colon, rectal, thyroid gland, stomach, and female breast cancers. The effect of the combination of abnormal lipid score and lifestyle on cancer was also estimated.

RESULTS

A total of 926 incident cancer cases were identified. In the RCS analysis, hazard ratios (HRs) of overall cancer for individuals with TC < 5.18 mmol/L or with LDL-C < 3.40 mmol/L were higher. Low TC was associated with higher colorectal cancer risk (HR [95% CI] = 1.76 [1.09-2.84]) and low HDL-C increased thyroid cancer risk by 90%. Abnormal lipid score was linearly and positively associated with cancer risk, and smokers with high abnormal lipid scores had a higher cancer risk, compared to non-smokers with low abnormal lipid scores (P < 0.05).

CONCLUSIONS

Low TC levels were associated with an increased risk of overall and colorectal cancer. More attention should be paid to participants with high abnormal lipid scores and unhealthy lifestyles who may have a higher risk of developing cancer. Determining the specific and comprehensive lipid combinations that affect tumorigenesis remains a valuable challenge.

Functional Potassium Channels in Macrophages

Macrophages are the predominant component of innate immunity, which is an important protective barrier of our body. Macrophages are present in all organs and tissues of the body, their main functions include immune surveillance, bacterial killing, tissue remodeling and repair, and clearance of cell debris. In addition, macrophages can present antigens to T cells and facilitate inflammatory response by releasing cytokines. Macrophages are of high concern due to their crucial roles in multiple physiological processes. In recent years, new advances are emerging after great efforts have been made to explore the mechanisms of macrophage activation. Ion channel is a class of multimeric transmembrane protein that allows specific ions to go through cell membrane. The flow of ions through ion channel between inside and outside of cell membrane is required for maintaining cell morphology and intracellular signal transduction. Expressions of various ion channels in macrophages have been detected. The roles of ion channels in macrophage activation are gradually caught attention. K⁺ channels are the most studied channels in immune system. However, very few of published papers reviewed the studies of K⁺ channels on macrophages. Here, we will review the four types of K⁺ channels that are expressed in macrophages: voltage-gated K⁺ channel, calcium-activated K⁺ channel, inwardly rectifying K⁺ channel and two-pore domain K⁺ channel.

Kir2.1 channel regulates macrophage polarization via Ca2+/CaMK II/ERK/NF-κB signaling pathway

Macrophage polarization plays a key role in inflammatory response. Various ion channels expressed in macrophages has been documented, but very little is known about their roles in macrophage polarization. We find that knockdown or blockade of Kir2.1 channel significantly inhibits M1 polarization, but promotes M2 polarization. LPS induced M1 polarization is also remarkably suppressed in high extracellular K+ solutions (70 mM K+), and this inhibition is partially abolished by adding Ca2+ in the culture medium. Calcium imaging shows that Ca2+ influx is dependent on the hyperpolarized membrane potential generated by Kir2.1 channel. The upregulation of p-CaMK II, p-ERK1/2, and p-NF-κB proteins in RAW264.7 macrophages stimulated with LPS are significantly reversed by blocking Kir2.1 channel or culturing the cells with 70 mM K+ medium. Furthermore, in vivo study shows that mice treated with Kir2.1 channel blocker are protected from LPS-induced peritonitis. In summary, our data reveal the essential role of Kir2.1 channel in regulating macrophage polarization via Ca2+ / CaMK II / ERK1/2 / NF-κB pathway.

[Mechanism of silk hydrates on modulating the blood glucose metabolism in rats with experimental diabetes]

Thirty eight adult male Wistar rats injected with streptozotocin(STZ) 30 mg/kg BW via tail vein and fed on a diet of high fat, high sucrose and high calorie for 3 weeks and then for another 8 weeks were successfully established as the diabetes model(type II diabetes mellitus). The effects of feeding silk hydrates(SH) for 12 weeks on the activities of insulin receptors and postreceptors were observed. The results showed that: 1) SH greatly improved the glucose tolerance of diabetic rats, but no effect on the secretion of insulin in rats with or without diabetes; 2) Only the low-affinity constant of insulin binding rates(K2) in skeletal muscle cell membranes of diabetic rats fed with SH were obviously increased, the high-affinity binding constant and the number of receptors were not changed; 3) the uptake of glucose in skeletal muscle of diabetic rats fed on SH was significantly increased. 4) SH partly improved the metabolism of serum lipids. The results indicated that SH could modulate the metabolism of blood glucose mainly through the mechanism on the activity of insulin postreceptor.

[Effects of silk hydrates on the blood glucose metabolism in rats with experimental diabetes]

Male Wistar rats were divided into two groups by random. One group was injected with streptozotocin(STZ) 30 mg/kg BW via tail vein. Three weeks later, the rats were fed on diet of high fat, high sucrose and high calorie for another 8 weeks. There were 38 rats with impaired glucose tolerance and insulin level higher or equal to the control group selected as the diabetic model group. Another 36 rats not injected with STZ and fed on normal diet were selected as controls. The two groups were divided into two subgroups and fed with normal diet for another 4 weeks. The four subgroups were normal control group, normal +SH group, diabetes control group and diabetes +SH group. The rats in normal +SH group and diabetes +SH group were tube feeding every day with silk hydrate (SH) 1.0 g/kg BW for 4 weeks. The results showed that in the diabetes +SH group, the glucose tolerance, blood lipid and the predictive index of coronary heart disease were significantly improved, but no effect on their blood insulin level. There was no change in the normal +SH group. The results suggested that SH could modulate the metabolism of blood glucose and partly improve the disorder of the serum lipid of diabetic rats.

[The cytologic ultrastructure and cytochemical features of human dendritic cells from peripheral blood]

OBJECTIVE

To observe the cytomorphological, cellular ultrastructure and cytochemical features of the dendritic cell (DC) enriched populations in vitro.

METHODS

Fresh peripheral blood from healthy volunteers was collected and mononuclear cells (PBMC) were isolated on lymphocyte separating solution. The PBMC were cultured in mediums containing rhGM-CSF, rhIL-4 and rhTNF-alpha 9-12 days to generate DC-enriched populations, the morphological features and numbers of DC were identified and counted respectively by light microscope (LM) and confirmed by immunofluorescence assay (IFA), the ultrastructure characteristics of the DC populations were observed by transmission electron microscope, and the cytochemical features of them were also examined.

RESULTS

The percentage of DCs was 70%-80% in the DC-enriched populations as confirmed by IFA using mABXII. Transmission electron microscopy revealed that the DC populations contained two subsets of DC, one was considered as precursor cell derived DC(PC-DC), the cell surface of which had many irregular dendrites with a irregular nucleus, small nucleoli, numerous mitochondria, but scanty lysosomes, ribosome, rough endoplasmic reticulum and free polysomes. Cytochemical staining showed the DCs were both peroxidase (POX) and non-specific esterase (NSE) negative. The other was indentified as monocyte-derived DC(MO-DC), the features of which included: irregular shape, many ruffles and some rough lames on cell surfaces, nephritic or horseshoe nuclei with a thick rim of heterochromatin, numerous mitochondria, much more lysosomes, ribosomes, rough endoplasmic reticulum and Golgiosome. The cytochemical reactions indicated that most of them had POX-positive granules, and were NSE slightly positive.

CONCLUSION

Cytokines in vitro induced DCs from human peripheral blood are heterogeneous.