Visfatin/NAMPT (nicotinamide phosphoribosyltransferase) is a protein with several suggested functions. Although the first discovery of this molecule as a pre-B-cell colony-enhancing factor suggested ...primarily a cytokine function, its rediscovery as the key enzyme in nicotinamide adenine dinucleotide generation has considerably widened its potential biological activities. Although originally thought to be produced in adipose tissue (i.e., adipocytes and infiltrating macrophages), its production seems to involve other cells and tissues such as skeletal muscle, liver, immune cells, cardiomyocytes, and the brain. Visfatin/NAMPT has both intracellular and extracellular effects influencing several signaling pathways. Its broad spectrum of effects is mirrored by its potential involvement in a wide range of disorders including human immunodeficiency virus infection, septicemia, myocardial failure, atherosclerosis, metabolic disorders, inflammatory diseases, malignancies, and neurodegenerative disorders and aging. Moreover, studies on visfatin/NAMPT in atherosclerotic disorders suggest a rather complex role of this molecule in pathophysiology, potentially mediating both adaptive and maladaptive responses.
Abstract
Aims
We recently reported five cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) 7–10 days after receiving the first dose of the ChAdOx1 nCoV-19 adenoviral vector vaccine ...against corona virus disease 2019 (COVID-19). We aimed to investigate the pathogenic immunological responses operating in these patients.
Methods and results
We assessed circulating inflammatory markers by immune assays and immune cell phenotyping by flow cytometry analyses and performed immunoprecipitation with anti-platelet factor (PF)4 antibody in plasma samples followed by mass spectrometry from all five patients. A thrombus was retrieved from the sinus sagittal superior of one patient and analysed by immunohistochemistry and flow cytometry. Precipitated immune complexes revealed multiple innate immune pathway triggers for platelet and leucocyte activation. Plasma contained increased levels of innate immune response cytokines and markers of systemic inflammation, extensive degranulation of neutrophils, and tissue and endothelial damage. Blood analyses showed activation of neutrophils and increased levels of circulating H3Cit, dsDNA, and myeloperoxidase–DNA complex. The thrombus had extensive infiltration of neutrophils, formation of neutrophil extracellular traps (NETs), and IgG deposits.
Conclusions
The results show that anti-PF4/polyanion IgG-mediated thrombus formation in VITT patients is accompanied by a massive innate immune activation and particularly the fulminant activation of neutrophils including NETosis. These results provide novel data on the immune response in this rare adenoviral vector-induced VITT.
Graphical Abstract
More than 170 post-transcriptional RNA modifications regulate the localization, processing and function of cellular RNAs, and aberrant RNA modifications have been linked to a range of human diseases. ...The RNA modification landscape in atherosclerosis, the main underlying cause of cardiovascular diseases, is still largely unknown.
We used mass spectrometry to analyse a selection of RNA-modifying enzymes and the N6-methyladenosine (m6A) in carotid atherosclerotic lesion samples representing early and advanced stages of atherosclerosis as compared to non-atherosclerotic arteries from healthy controls.
(i) the detection of different levels of several enzymes involved in methylations occurring in rRNA and mRNA; (ii) these findings included changes in the levels of methyltransferases (‘writers’), binding proteins (‘readers’) and demethylases (‘erasers’) during atherosclerosis as compared to non-atherosclerotic control arteries, with generally the most prominent differences in samples from early atherosclerotic lesions; and (iii) these changes were accompanied by a marked downregulation of m6A in rRNA, the most abundant and well-studied modification in mRNA with a wide range of effects on cell biology.
We show for the first time that RNA-modifying enzymes and the well-studied RNA modification m6A are differentially regulated in atherosclerotic lesions, which potentially could help creating new prognostic and treatment strategies.
•Post-transcriptional RNA-methylation enzymes are regulated in atherosclerosis.•Levels of m6A are reduced in total RNA from human atherosclerotic samples.•These are the first data showing epitranscriptomic modifications in atherosclerosis.
A substantial proportion of patients with common variable immunodeficiency (CVID) have inflammatory and autoimmune complications of unknown etiology. We have previously shown that systemic ...inflammation in CVID correlates with their gut microbial dysbiosis. The gut microbiota dependent metabolite trimethylamine N-oxide (TMAO) has been linked to several metabolic and inflammatory disorders, but has hitherto not been investigated in relation to CVID. We hypothesized that TMAO is involved in systemic inflammation in CVID. To explore this, we measured plasma concentrations of TMAO, inflammatory markers, and lipopolysaccharide (LPS) in 104 CVID patients and 30 controls. Gut microbiota profiles and the bacterial genes
and
, which encode enzymes that can convert dietary metabolites to trimethylamine in the colon, were examined in fecal samples from 40 CVID patients and 86 controls. Furthermore, a food frequency questionnaire and the effect of oral antibiotic rifaximin on plasma TMAO concentrations were explored in these 40 patients. We found CVID patients to have higher plasma concentrations of TMAO than controls (TMAO 5.0 2.9-8.6 vs. 3.2 2.2-6.3,
= 0.022, median with IQR). The TMAO concentration correlated positively with tumor necrosis factor (
= 0.008, rho = 0.26), interleukin-12 (
= 0.012, rho = 0.25) and LPS (
= 0.034, rho = 0.21). Dietary intake of meat (
= 0.678), fish (
= 0.715), egg (
= 0.138), dairy products (
= 0.284), and fiber (
= 0.767) did not significantly impact on the TMAO concentrations in plasma, nor did a 2-week course of the oral antibiotic rifaximin (
= 0.975). However, plasma TMAO concentrations correlated positively with gut microbial abundance of
(
= 0.021, rho = 0.36). Bacterial gene
was present in significantly more CVID samples (75%) than controls (53%),
= 0.020, potentially related to the increased abundance of
in these samples. The current study demonstrates that elevated TMAO concentrations are associated with systemic inflammation and increased gut microbial abundance of
in CVID patients, suggesting that TMAO could be a link between gut microbial dysbiosis and systemic inflammation. Gut microbiota composition could thus be a potential therapeutic target to reduce systemic inflammation in CVID.
Purpose
Triglycerides (TG) and their major transport lipoprotein in the circulation (VLDL) appear to be related to inflammation. Patients with common variable immunodeficiency (CVID) have ...inflammatory complications associated with gut microbial dysbiosis. We hypothesized that CVID patients have disturbed TG/VLDL profiles associated with these clinical characteristics.
Methods
We measured plasma concentrations of TGs, inflammatory markers, and lipopolysaccharide (LPS) in 95 CVID patients and 28 healthy controls. Additionally, in 40 CVID patients, we explored plasma lipoprotein profiling, fatty acid, gut microbial dysbiosis, and diet.
Results
TG levels were increased in CVID patients as compared to healthy controls (1.36 ± 0.53 mmol/l versus 1.08 ± 0.56 mean, SD, respectively,
P
= 0.008), particularly in the clinical subgroup “
Complications
,” characterized by autoimmunity and organ-specific inflammation, compared to “
Infection only
” (1.41 mmol/l, 0.71median, IQR versus 1.02 mmol/l, 0.50,
P
= 0.021). Lipoprotein profile analyses showed increased levels of all sizes of VLDL particles in CVID patients compared to controls. TG levels correlated positively with CRP (rho = 0.256,
P
= 0.015), IL-6 (rho = 0.237,
P
= 0.021), IL-12 (rho = 0.265,
P
= 0.009), LPS (
r
= 0.654,
P
= 6.59 × 10
−13
), CVID-specific gut dysbiosis index (
r
= 0.315,
P
= 0.048), and inversely with a favorable fatty acid profile (docosahexaenoic acid rho = − 0.369,
P
= 0.021 and linoleic acid rho = − 0.375,
P
= 0.019). TGs and VLDL lipids did not appear to be associated with diet and there were no differences in body mass index (BMI) between CVID patients and controls.
Conclusion
We found increased plasma levels of TGs and all sizes of VLDL particles, which were associated with systemic inflammation, LPS, and gut dysbiosis in CVID, but not diet or BMI.
Atherosclerosis is a major cause of cerebrovascular disease. Matrix metalloproteinases (MMPs) play an important role in matrix degradation within the atherosclerotic lesion leading to plaque ...destabilization and ischemic stroke. We hypothesized that MMP-7 could be involved in this process.
Plasma levels of MMP-7 were measured in 182 consecutive patients with moderate (50-69%) or severe (≥70%) internal carotid artery stenosis, and in 23 healthy controls. The mRNA levels of MMP-7 were measured in atherosclerotic carotid plaques with different symptomatology, and based on its localization to macrophages, the in vitro regulation of MMP-7 in primary monocytes was examined.
Our major findings were (i) Patients with carotid atherosclerosis had markedly increased plasma levels of MMP-7 compared to healthy controls, with particularly high levels in patients with recent symptoms (i.e., within the last 2 months). (ii) A similar pattern was found within carotid plaques with markedly higher mRNA levels of MMP-7 than in non-atherosclerotic vessels. Particularly high protein levels of MMP-7 levels were found in those with the most recent symptoms. (iii) Immunhistochemistry showed that MMP-7 was localized to macrophages, and in vitro studies in primary monocytes showed that the inflammatory cytokine tumor necrosis factor-α in combination with hypoxia and oxidized LDL markedly increased MMP-7 expression. (iv) During the follow-up of patients with carotid atherosclerosis, high plasma levels of MMP-7 were independently associated with total mortality.
Our findings suggest that MMP-7 could contribute to plaque instability in carotid atherosclerosis, potentially involving macrophage-related mechanisms.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Soluble lectin‐like oxidized low‐density lipoprotein receptor‐1 (sLOX‐1) has been shown to be increased in patients with acute ischemic stroke. Here, we evaluated plasma sLOX‐1 levels and ...vascular carotid plaque LOX‐1 (ie, OLR1) gene expression in patients with ischemic stroke and transient ischemic attack (TIA) with particular focus on their relation to time since symptom onset.
Methods and Results
Plasma sLOX‐1 (n=232) and carotid plaque OLR1 gene expression (n=146) were evaluated in patients who were referred to evaluation for carotid endarterectomy, as well as in healthy control plasma (n=81). Patients were categorized according to presence of acute ischemic stroke or transient ischemic attack (n=35) ≤7 days, >7 days ≤3 months (n=90), >3 months (n=40), or no reported symptoms before study inclusion (n=67). Our major findings were the following: (1) Patients with carotid atherosclerosis had increased plasma sLOX‐1 levels as compared with controls. (2) Plaque OLR1 mRNA levels were increased in carotid plaques (n=146) compared with nonatherosclerotic vessels (ie, common iliac arteries of organ donors, n=10). (3) There were no differences in sLOX plasma levels or OLR1 gene expression when analyzed according to the time since relevant cerebral ischemic symptoms. (4) Also patients with severe carotid atherosclerosis without any previous ischemic events had raised sLOX‐1 levels. (5) Immunostaining showed colocalization between LOX‐1 and macrophages within the carotid plaques. (6) Also patients with acute stroke (within 7 days) caused by atrial fibrillation (n=22) had comparable raised sLOX‐1 levels.
Conclusions
sLOX‐1 levels are elevated in patients with ischemic stroke and transient ischemic attack independent of cause and time since the ischemic event.
The global risk of cardiovascular disease, including ischemic disease such as stroke, remains high, and cardiovascular disease is the cause of one-third of all deaths worldwide. The main subjacent ...cause, atherosclerosis, is not fully understood. To improve early diagnosis and therapeutic strategies, it is crucial to unveil the key molecular mechanisms that lead to atherosclerosis development. The field of epitranscriptomics is blossoming and quickly advancing in fields like cancer research, nevertheless, poorly understood in the context of cardiovascular disease. Epitranscriptomic modifications are shown to regulate the metabolism and function of RNA molecules, which are important for cell functions such as cell proliferation, a key aspect in atherogenesis. As such, epitranscriptomic regulatory mechanisms can serve as novel checkpoints in gene expression during disease development. In this review, we describe examples of the latest research investigating epitranscriptomic modifications, in particular A-to-I editing and the covalent modification
-methyladenosine and their regulatory proteins, in the context of cardiovascular disease. We additionally discuss the potential of these mechanisms as therapeutic targets and novel treatment options.
ObjectiveFetuin A has been associated with insulin resistance and the metabolic syndrome. We therefore explored the role of fetuin A in nonalcoholic fatty liver disease (NAFLD).DesignCross-sectional ...and intervention studies.MethodsWe included 111 subjects with histologically proven NAFLD of whom 44 participated in a randomized, controlled trial with metformin. One hundred and thirty-one healthy subjects and 13 subjects undergoing hepatic surgery for metastatic cancer served as controls. Main outcome variables were circulating levels of fetuin A according to the presence of NAFLD, hepatic gene expression of fetuin A and key enzymes in glucose and lipid metabolism, and the effect of metformin on fetuin A levels in vivo and in vitro (HepG2 cells).ResultsFetuin A levels were significantly higher in NAFLD patients compared with controls (324±98 vs 225±75 mg/l, P<0.001). NAFLD was a significant predictor of elevated fetuin A levels (β=174 (95% confidence interval: 110–234)) independent of body mass index, age, sex, fasting glucose, and triglycerides. Hepatic fetuin A mRNA levels correlated significantly with hepatic mRNA levels of key enzymes in lipid (sterol regulatory element-binding protein 1c, carnitine palmitoyltransferase 1) and glucose (phosphoenol pyruvate kinase 1, glucose-6-phosphatase) metabolism. Plasma fetuin A levels decreased significantly after metformin treatment compared with placebo (−40±47 vs 15±82 mg/l, P=0.008). Metformin induced a dose-dependent decrease in fetuin A secretion in vitro.ConclusionsFetuin A levels were elevated in NAFLD. Hepatic expression of fetuin A correlated with key enzymes in glucose and lipid metabolism. Metformin decreased fetuin A levels in vitro.
The Omicron variant of SARS-CoV-2 spreads more easily than earlier variants, possibly as a result of a higher viral load in the upper respiratory tract and oral cavity. Hence, we investigated whether ...the Omicron variant generates a higher viral load than that of the Delta variant in saliva and nasopharynx. Both specimens were collected from 52 Omicron and 17 Delta cases at two time points one week apart and analyzed by qRT-PCR. Viral load was measured as 10 log RNA genome copies per 1000 human cells according to the WHO reference standard. We found that Omicron cases carried a higher viral load and had more sustained viral shedding compared to the Delta cases, especially in the nasopharynx.
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