The impacts of dietary sphingomyelin supplementation on metabolic parameters of healthy adults: a systematic review and meta-analysis of randomized controlled trials.

Background: Studies have shown that sphingomyelin (SM) and its metabolites play signaling roles in the regulation of human health. Endogenous SM is involved in metabolic syndrome (MetS), while dietary SM supplementation may maintain lipid metabolism and prevent or alleviate MetS. Therefore, we hypothesized that dietary SM supplementation is beneficial for human health. Aims: In order to examine the impacts of dietary SM on metabolic indexes in adults without MetS, we performed a meta-analysis to test our hypothesis. Methods: A comprehensive search was performed to retrieve randomized controlled trials that were conducted between 2003 and 2023 to examine the effects of dietary SM supplementation on metabolic parameters in the Cochrane Library, PubMed, Web of Science, Embase, and ClinicalTrials.gov databases. RevMan 5.4 and Stata 14.0 software were used for meta-analysis, a sensitivity analysis, the risk of bias, and the overall quality of the resulted evidence. Results: Eventually, 10 articles were included in this meta-analysis. Dietary SM supplementation did not affect the endline blood SM level. When compared to the control, SM supplementation reduced the blood total cholesterol level [MD: -12.97, 95% CI: (-14.57, -11.38), p < 0.00001], low-density lipoprotein cholesterol level [MD: -6.62, 95% CI: (-10.74, -2.49), p = 0.002], and diastolic blood pressure [MD: -3.31; 95% CI (-4.03, -2.58), p < 0.00001] in adults without MetS. The supplementation also increased high-density lipoprotein level [MD:1.41, 95% CI: (0.94, 1.88), p < 0.00001] and muscle fiber conduction velocity [MD: 95% 1.21 CI (0.53, 1.88), p = 0.0005]. The intake of SM had no effect on the blood phospholipids and lyso-phosphatidylcholine, but slightly decreased phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol concentrations. Dietary SM supplementation reduced insulin level [MD: -0.63; 95% CI (-0.96, -0.31), p = 0.0001] and HOMA-IR [MD: -0.23; 95% CI (-0.31, -0.16), p < 0.00001] without affecting blood levels of glucose and inflammatory cytokines. Conclusion: Overall, dietary SM supplementation had a protective effect on blood lipid profiles and insulin level, but had limited impacts on other metabolic parameters in adults without MetS. More clinical trials and basic research are required. Systematic review registration: PROSPERO, identifier CRD42023438460.

Urotensin II level is elevated in inflammatory bowel disease patients.

It was reported that the urotensin II (U-II) level in inflammatory bowel disease (IBD) patients are significantly higher than in controls. To provide future guidance for the management of cardiovascular risk factors in IBD patients, the sample size of the current study appears to be limited, and more clinical samples to compare U-II levels in IBD patients and controls are needed. This will clarify the possible roles of inflammation factors and related signaling pathways (like EPK1/2, NF-κB and Rho/ROCK) in the pathophysiology of IBD. Therefore, large multicenter studies should be done to confirm the findings and underlying mechanisms in the future.

Roles of vitamin A in the regulation of fatty acid synthesis.

Dietary macronutrients and micronutrients play important roles in human health. On the other hand, the excessive energy derived from food is stored in the form of triacylglycerol. A variety of dietary and hormonal factors affect this process through the regulation of the activities and expression levels of those key player enzymes involved in fatty acid biosynthesis such as acetyl-CoA carboxylase, fatty acid synthase, fatty acid elongases, and desaturases. As a micronutrient, vitamin A is essential for the health of humans. Recently, vitamin A has been shown to play a role in the regulation of glucose and lipid metabolism. This review summarizes recent research progresses about the roles of vitamin A in fatty acid synthesis. It focuses on the effects of vitamin A on the activities and expression levels of mRNA and proteins of key enzymes for fatty acid synthesis in vitro and in vivo. It appears that vitamin A status and its signaling pathway regulate the expression levels of enzymes involved in fatty acid synthesis. Future research directions are also discussed.

Current understanding of glucose transporter 4 expression and functional mechanisms.

Glucose is used aerobically and anaerobically to generate energy for cells. Glucose transporters (GLUTs) are transmembrane proteins that transport glucose across the cell membrane. Insulin promotes glucose utilization in part through promoting glucose entry into the skeletal and adipose tissues. This has been thought to be achieved through insulin-induced GLUT4 translocation from intracellular compartments to the cell membrane, which increases the overall rate of glucose flux into a cell. The insulin-induced GLUT4 translocation has been investigated extensively. Recently, significant progress has been made in our understanding of GLUT4 expression and translocation. Here, we summarized the methods and reagents used to determine the expression levels of Slc2a4 mRNA and GLUT4 protein, and GLUT4 translocation in the skeletal muscle, adipose tissues, heart and brain. Overall, a variety of methods such real-time polymerase chain reaction, immunohistochemistry, fluorescence microscopy, fusion proteins, stable cell line and transgenic animals have been used to answer particular questions related to GLUT4 system and insulin action. It seems that insulin-induced GLUT4 translocation can be observed in the heart and brain in addition to the skeletal muscle and adipocytes. Hormones other than insulin can induce GLUT4 translocation. Clearly, more studies of GLUT4 are warranted in the future to advance of our understanding of glucose homeostasis.

Clinical use of low-dose aspirin for elders and sensitive subjects.

The use of low-dose aspirin (LDA) has been a common preventive measure to reduce the risk of cardiovascular events. This is attributed to aspirin's ability to inhibit platelet activation. On the other hand, the use of LDA in human subjects has been associated with the development of gastrointestinal injuries like ulcer and bleeding, especially for those sensitive subjects such as elder human subjects. This opinion review will summarize the recent clinical reports regarding the use of LDA and the development of gastrointestinal conditions in China. Based on these reports, it seems that the use of LDA is commonly associated with gastrointestinal injuries, and stopping its use leads to recovery in elderly subjects. Therefore, we would like to suggest that gastroduodenal health and conditions should be seriously taken into consideration when LDA is recommended to the elderly, or other alternative means to reduce the risk of cardiovascular events such as nutritional interventions should be suggested.

Production of extracellular lysophosphatidic acid in the regulation of adipocyte functions and liver fibrosis.

Lysophosphatidic acid (LPA), a glycerophospholipid, consists of a glycerol backbone connected to a phosphate head group and an acyl chain linked to sn-1 or sn-2 position. In the circulation, LPA is in sub-millimolar range and mainly derived from hydrolysis of lysophosphatidylcholine, a process mediated by lysophospholipase D activity in proteins such as autotaxin (ATX). Intracellular and extracellular LPAs act as bioactive lipid mediators with diverse functions in almost every mammalian cell type. The binding of LPA to its receptors LPA1-6 activates multiple cellular processes such as migration, proliferation and survival. The production of LPA and activation of LPA receptor signaling pathways in the events of physiology and pathophysiology have attracted the interest of researchers. Results from studies using transgenic and gene knockout animals with alterations of ATX and LPA receptors genes, have revealed the roles of LPA signaling pathways in metabolic active tissues and organs. The present review was aimed to summarize recent progresses in the studies of extracellular and intracellular LPA production pathways. This includes the functional, structural and biochemical properties of ATX and LPA receptors. The potential roles of LPA production and LPA receptor signaling pathways in obesity, insulin resistance and liver fibrosis are also discussed.

Case report and review of the literature of primary gastrointestinal amyloidosis diagnosed with enteroscopy and endoscopic ultrasonography.

Here, we report a rare case of primary gastrointestinal amyloidosis in a stable condition after being followed up for three years. The patient was admitted to the hospital in 2014. Tests showed decreased levels of hemoglobin and ferritin. Transoral and transanal enteroscopy showed multiple nodular protuberances in the esophagus, ileum, colon and rectum. Endoscopic ultrasonography indicated the nodular protuberances stemmed from the submucosa and partially invaded the intrinsic myometrium. Pathological examinations found multiple small nodules in the submucosa and dyed structures, which were positive for special Congo red dyeing. After treatment with oral iron supplements, the levels of hemoglobin and ferritin became normal. It is concluded that the patient represents a case of primary gastrointestinal amyloidosis with multiple nodular protuberances in the digestive tract with controllable moderate abdominal discomfort and anemia and a benign course. Enteroscopy and endoscopic ultrasonography play an important role in the diagnosis of primary gastrointestinal amyloidosis.

Increased Eating Frequency Is Associated with Lower Obesity Risk, But Higher Energy Intake in Adults: A Meta-Analysis.

Body weight is regulated by energy intake which occurs several times a day in humans. In this meta-analysis, we evaluated whether eating frequency (EF) is associated with obesity risk and energy intake in adults without any dietary restriction. Experimental and observational studies published before July 2015 were selected through English-language literature searches in several databases. These studies reported the association between EF and obesity risk (odd ratios, ORs) in adults who were not in dietary restriction. R software was used to perform statistical analyses. Ten cross-sectional studies, consisting of 65,742 participants, were included in this analysis. ORs were considered as effect size for the analysis about the effect of EF on obesity risk. Results showed that the increase of EF was associated with 0.83 time lower odds of obesity (i.e., OR = 0.83, 95% confidence intervals (CI) 0.70-0.99, p = 0.040). Analysis about the effect of EF on differences in participants' energy intake revealed that increased EF was associated with higher energy intake (ß = 125.36, 95% CI 21.76-228.97, p = 0.017). We conclude that increased EF may lead to lower obesity risk but higher energy intake. Clinical trials are warranted to confirm these results and to assess the clinical practice applicability.

Changes of osteocalcin and IGF-I during bone lengthening.

OBJECTIVE: To examine the changes of osteocalcin and insulin-like growth factor I (IGF-I) during bone lengthening, and to clarify the mechanism of bone healing. METHODS: Thirty-two shepherd dogs were divided into five groups randomly. Their tibiae were lengthened by Ilvzarov's external fixator at the rate of 1 mm/day. The lengthening area was the experimental side and the opposite side was the control. Samples were obtained on the 2nd, 4th, 6th, 8th, 12th weekend respectively. The samples were defatted, dried, powdered, centrifuged and measured by radioimmunoassay. RESULTS: The osteocalcin concentration increased at the subsequent periods, but it was significantly lower in the experimental side than that of the control side, P<0.05 and the IGF-I concentration was not significantly lowered. CONCLUSIONS: Different noncollagenous bone growth factors may be different at different stage.

Component changes of calcium and phosphorus in osteogenesis by lengthening procedures in adult canines.

OBJECTIVE: To explore chemical component changes of dog bone at different lengthening time and in different bone regions of interest, and to evaluate the mineralization during Ilizarov lengthening process. METHODS: The ash weight, the concentrations of calcium, phosphorus and the calcium/phosphorus ratio were measured at different intervals (2, 4, 6, 8, 12 weeks) since lengthening and the lengthened part was compared with a control area at each interval. RESULTS: The ash weight, the concentrations of calcium and phosphorus in the lengthened area differed at all development time. The calcium/phosphorus (Ca/P) ratio in the lengthened region remained significantly lower than that in the control region up to 12 weeks after the lengthening. CONCLUSIONS: These results suggest that also other inorganic ions play an important role in the mineralization process and that they become relatively more important since 8 weeks after the lengthening.