Serum amyloid A, a host-derived DAMP in pregnancy?

CiteSpace-based visual analysis on transcutaneous electrical acupoint stimulation of clinical randomized controlled trial studies and its mechanism on perioperative disorders

To systematically present an overview of randomized controlled trials on transcutaneous electrical acupoint stimulation (TEAS) using bibliometric methods, and describe the role and mechanisms of TEAS in most prevalent diseases. Relevant literature was searched in China National Knowledge Infrastructure, Wanfang Data, VIP, SinoMed, PubMed, and Web of Science. The literature was imported and screened into NoteExpress, screened according to inclusion and exclusion criteria, and analyzed using Excel and CiteSpace 6.3R1 software. A total of 1296 documents were included. The number of publications increased annually after 2012. Junlu Wang was the most prolific author. The main research institutions were Peking University, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Shuguang Hospital, and Tongde Hospital of Zhejiang Province. The research hotspots in this field include perioperative care, cancer, pain management, and stroke, primarily focusing on analgesia, immune enhancement, antihypertension, and reduction of gastrointestinal disorders. The main regulatory mechanisms of TEAS include the control of inflammation, oxidative stress, and regulation of the autonomic nervous system. TEAS is most widely used in the elderly, with PC6, ST36, and LI4 being the most frequently studied acupoints in clinical randomized controlled trials. The concept of accelerated rehabilitation is gradually being applied to TEAS, representing an emerging trend for future development. Clinical research on TEAS is rapidly developing, with a focus on applications in cancer and perioperative care. Future research should expand collaboration and conduct high-level clinical and mechanistic studies, which will contribute to the development of standardized protocols and clinical practice.

Differences in HDL Remodeling during Healthy Pregnancy and Pregnancy with Cardiometabolic Complications

This study investigated the longitudinal trajectory of changes in antioxidative and anti-inflammatory high-density lipoprotein (HDL) components during healthy pregnancy and pregnancy with cardiometabolic complications. We recruited and longitudinally followed 84 women with healthy pregnancies and 46 pregnant women who developed cardiometabolic pregnancy complications (gestational diabetes mellitus and hypertensive disorders of pregnancy). Their general lipid profiles, oxidative stress status, inflammatory status, and antioxidative and anti-inflammatory HDL components were analyzed. The results of our study confirmed the expected trajectory for the routine lipid parameters. Our study results indicate more intensive oxidative stress and a higher level of inflammation in the group with complications compared with the control group. Sphingosine-1-phosphate (S1P) was significantly lower in the first trimester in the group with complications compared with the control group (p < 0.05). We did not find significant differences in the apolipoprotein A1 (Apo A1) concentrations in the first trimester between the control group and the group with complications, but in the second and third trimesters, the group with complications had significantly higher concentrations (p < 0.001, p < 0.05, respectively). The S1P, paraoxonase 1 (PON1), and serum amyloid A (SAA) concentrations were significantly lower in the group with complications in the first trimester. During the second trimester, only the SAA concentrations were identified as significantly lower in the group with complications compared with the control group, while in the third trimester, the PON1, apolipoprotein M (Apo M), and SAA concentrations were all significantly lower in the group with complications. Through a multivariate binary logistic regression analysis, the S1P concentration in the first trimester was distinguished as an HDL-associated marker independently associated with cardiometabolic pregnancy complications. In conclusion, our study results showed that HDL remodeling differs between healthy pregnancies and pregnancies with maternal cardiometabolic complications, with changed HDL composition and functionality consequently impacting its biological functionality in the latter case.

Serum amyloid A aggravates endotoxin-induced ocular inflammation through the regulation of retinal microglial activation

Serum amyloid A (SAA) are major acute-phase response proteins which actively participate in many inflammatory diseases. This study was designed to explore the function of SAA in acute ocular inflammation and the underlying mechanism. We found that SAA3 was upregulated in endotoxin-induced uveitis (EIU) mouse model, and it was primarily expressed in microglia. Recombinant SAA protein augmented intraocular inflammation in EIU, while the inhibition of Saa3 by siRNA effectively alleviated the inflammatory responses and rescued the retina from EIU-induced structural and functional damage. Further study showed that the recombinant SAA protein activated microglia, causing characteristic morphological changes and driving them further to pro-inflammatory status. The downregulation of Saa3 halted the amoeboid change of microglia, reduced the secretion of pro-inflammatory factors, and increased the expression of tissue-reparative genes. SAA3 also regulated the autophagic activity of microglial cells. Finally, we showed that the above effect of SAA on microglial cells was at least partially mediated through the expression and signaling of Toll-like receptor 4 (TLR4). Collectively, our study suggested that microglial cell-expressed SAA could be a potential target in treating acute ocular inflammation.

Maternal Serum Amyloid A as a Marker of Preterm Birth/PROM: A Systematic Review and Meta-Analysis

Background and Objectives: Preterm birth, one of the leading causes of neonatal mortality, occurs in between 5 and 18% of births. Premature birth can be induced by a variety of triggers, including infection or inflammation. Serum amyloid A, a family of apolipoproteins, increases significantly and rapidly at the onset of inflammation. This study aims to systematically review the results of studies in the literature that have examined the correlation between SAA and PTB/PROM. Materials and Methods: To examine the correlation between serum amyloid A levels in women who gave birth prematurely, a systematic analysis was performed according to PRISMA guidelines. Studies were retrieved by searching the electronic databases PubMed and Google Scholar. The primary outcome measure was the standardized mean difference in serum amyloid A level comparing the preterm birth or premature rupture of membranes groups and the term birth group. Results: Based on the inclusion criteria, a total of 5 manuscripts adequately addressed the desired outcome and were thus included in the analysis. All included studies showed a statistically significant difference in serum SAA levels between the preterm birth or preterm rupture of membranes groups and the term birth group. The pooled effect, according to the random effects model, is SMD = 2.70. However, the effect is not significant (p = 0.097). In addition, the analysis reveals an increased heterogeneity with an I² = 96%. Further, the analysis of the influence on heterogeneity found a study that has a significant influence on heterogeneity. However, even after outline exclusion, heterogeneity remained high I² = 90.7%. Conclusions: There is an association between increased levels of SAA and preterm birth/PROM, but studies have shown great heterogeneity.

Amnion-derived serum amyloid A1 participates in sterile inflammation of fetal membranes at parturition

OBJECTIVES

Sterile inflammation of fetal membranes is an indispensable event of normal parturition. However, triggers of sterile inflammation are not fully resolved. Serum amyloid A1 (SAA1) is an acute phase protein produced primarily by the liver. Fetal membranes can also synthesize SAA1 but its functions are not well defined. Given the role of SAA1 in the acute phase response to inflammation, we postulated that SAA1 synthesized in the fetal membranes may be a trigger of local inflammation at parturition.

METHODS

The changes of SAA1 abundance in parturition were studied in the amnion of human fetal membranes. The role of SAA1 in chemokine expression and leukocyte chemotaxis was examined in cultured human amnion tissue explants as well as primary human amnion fibroblasts. The effects of SAA1 on monocytes, macrophages and dendritic cells were investigated in cells derived from a human leukemia monocytic cell line (THP-1).

RESULTS

SAA1 synthesis increased significantly in human amnion at parturition. SAA1 evoked multiple chemotaxis pathways in human amnion fibroblasts along with upregulation of a series of chemokines via both toll-like receptor 4 (TLR4) and formyl peptide receptor 2 (FPR2). Moreover, SAA1-conditioned medium of cultured amnion fibroblasts was capable of chemoattracting virtually all types of mononuclear leukocytes, particularly monocytes and dendritic cells, which reconciled with the chemotactic activity of conditioned medium of cultured amnion tissue explants collected from spontaneous labor. Furthermore, SAA1 could induce the expression of genes associated with inflammation and extracellular matrix remodeling in monocytes, macrophages and dendritic cells derived from THP-1.

CONCLUSIONS

SAA1 is a trigger of sterile inflammation of the fetal membranes at parturition.