Characterization of the L-Arginine/Nitric Oxide Pathway and Oxidative Stress in Pediatric Patients with Atopic Diseases

Liangxue-Qushi-Zhiyang Decoction Ameliorates DNCB-Induced Atopic Dermatitis in Mice through the MAPK Signaling Pathway Based on Network Pharmacology

The traditional prescription of Liangxue-Qushi-Zhiyang decoction (LQZ) has been demonstrated to be efficacious in treating atopic dermatitis (AD), a chronic inflammatory skin disorder marked by intense itching, redness, rashes, and skin thickening. Nevertheless, there has been an inadequate systematic exploration of the potential targets, biological processes, and pathways for AD treatment through LQZ. The study objective was to evaluate the efficacy and possible mechanism of LQZ in AD mice. In our study, we identified the primary compounds of LQZ, analyzed hub targets, and constructed a network. Subsequently, the predicted mechanisms of LQZ in AD were experimentally studied and validated in vivo, as determined by network pharmacological analysis. A total of 80 serum components of LQZ were identified through ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS), among which 49 compounds were absorbed into the bloodstream. Our results indicated that LQZ targets six putative key factors in the MAPK signaling pathway, which play essential roles in AD, namely, EGFR, p-MAPK1/3, p-MAPK14, IL-1β, IL-6, and TNF-α. We observed spleen coefficient, dermatitis scores, and ear thickness were all downregulated in 2,4-dinitrochlorobenzene (DNCB)-induced mice after LQZ treatment. Histological analysis of the dorsal and ear skin further revealed that LQZ significantly decreased skin inflammation, epidermal thickness, and mast cell numbers compared to the DNCB group. Our study demonstrated the effectiveness of LQZ in reducing epidermal and dermal damage in a mouse model of AD. Furthermore, our findings suggest that downregulating the MAPK signaling pathway could be a potential therapeutic strategy for the treatment of AD.

Risk prediction model construction for asthma after allergic rhinitis by blood immune T effector cells

BACKGROUND

Allergic rhinitis (AR) and asthma (AS) are prevalent and frequently co-occurring respiratory diseases, with mutual influence on each other. They share similar etiology, pathogenesis, and pathological changes. Due to the anatomical continuity between the upper and lower respiratory tracts, allergic inflammation in the nasal cavity can readily propagate downwards, leading to bronchial inflammation and asthma. AR serves as a significant risk factor for AS by potentially inducing airway hyperresponsiveness in patients. Currently, there is a lack of reliable predictors for the progression from AR to AS.

METHODS

In this exhaustive investigation, we reexamined peripheral blood single cell RNA sequencing datasets from patients with AS following AR and healthy individuals. In addition, we used the bulk RNA sequencing dataset as a validation lineup, which included AS, AR, and healthy controls. Using marker genes of related cell subtype, signatures predicting the progression of AR to AS were generated.

RESULTS

We identified a subtype of immune-activating effector T cells that can distinguish patients with AS after AR. By combining specific marker genes of effector T cell subtype, we established prediction models of 16 markers. The model holds great promise for assessing AS risk in individuals with AR, providing innovative avenues for clinical diagnosis and treatment strategies.

CONCLUSION

Subcluster T effector cells may play a key role in post-AR AS. Notably, ACTR3 and HSPA8 genes were significantly upregulated in the blood of AS patients compared to healthy patients.

Exhaled Nitric Oxide as Biomarker of Type 2 Diseases

Nitric oxide (NO) is a short-lived gas molecule which has been studied for its role as a signaling molecule in the vasculature and later, in a broader view, as a cellular messenger in many other biological processes such as immunity and inflammation, cell survival, apoptosis, and aging. Fractional exhaled nitric oxide (FeNO) is a convenient, easy-to-obtain, and non-invasive method for assessing active, mainly Th2-driven, airway inflammation, which is sensitive to treatment with standard anti-inflammatory therapy. Consequently, FeNO serves as a valued tool to aid the diagnosis and monitoring of several asthma phenotypes. More recently, FeNO has been evaluated in several other respiratory and/or immunological conditions, including allergic rhinitis, chronic rhinosinusitis with/without nasal polyps, atopic dermatitis, eosinophilic esophagitis, and food allergy. In this review, we aim to provide an extensive overview of the current state of knowledge about FeNO as a biomarker in type 2 inflammation, outlining past and recent data on the application of its measurement in patients affected by a broad variety of atopic/allergic disorders.

Paper-based electrochemical immunosensor for the determination of symmetric dimethylarginine

In this work, we present the development of an immunosensor for the direct, selective, and sensitive determination of symmetric dimethylarginine (SDMA) in urine, in view of the emerging role of this molecule as a biomarker for renal disease. SDMA is almost completely excreted by the kidneys, hence in renal dysfunction, the excretion is decreased, resulting in accumulation in plasma. Reference values for plasma or serum have already been established in small animal practice. Values < 15 μg/dL are considered normal, 15-19 μg/dL are values of concern, and at values > 20 μg/dL kidney disease is likely. The proposed electrochemical paper-based sensing platform uses anti-SDMA antibodies for targeted detection of SDMA. Quantification is related to a decrease in the signal of a redox indicator due to the formation of an immunocomplex that interferes with electron transfer. Square wave voltammetry measurements showed a linear correlation of the peak decline for 50 nM - 1 μM SDMA with a detection limit of 15 nM. The influence of common physiological interferences caused no significant peak reduction, indicating excellent selectivity. The proposed immunosensor was successfully applied for the quantification of SDMA in human urine of healthy individuals. Surveillance of SDMA concentration in urine could prove to be very valuable in the diagnosis or monitoring of renal disease.

Developmental dynamics of homoarginine, ADMA and SDMA plasma levels from birth to adolescence

Guanidino compounds such as dimethylarginines (SDMA, ADMA) and L-homoarginine ((L-)hArg) can interfere with bioavailability and function of the main NO-donor L-arginine (L-Arg). High ADMA and SDMA but low L-hArg concentrations have been associated with cardio- and cerebrovascular events and mortality in adults. The role of guanidino compounds in paediatric patients remains less clear. We, therefore, compared guanidino compound levels in plasma samples of 57 individuals with chronic kidney disease (CKD) and 141 individuals without CKD from the age of 0 to 17 years, including patients with different comorbidities by correlation and regression analyses. We found highest hArg, SDMA and ADMA concentrations in neonates (Kruskal-Wallis, p < 0.001 for all). From the age of 1 year on, hArg levels increased, whereas SDMA und ADMA levels further decreased in children. SDMA and ADMA are higher in children with CKD independent of GFR (mean factor 1.92 and 1.38, respectively, p < 0.001 for both), and SDMA is strongly correlated with creatinine concentration in children with CKD (Spearman's rho 0.74, p < 0.001). We provide guanidino compound levels in a large sample covering all paediatric age groups for the first time. Our data can be used to assess the role of guanidino compounds such as hArg in disease states, i.e. cerebro- and cardiovascular disorders in childhood and adolescence.

Malondialdehyde as a Potential Oxidative Stress Marker for Allergy-Oriented Diseases: An Update

Malondialdehyde (MDA) is a compound that is derived from the peroxidation of polyunsaturated fatty acids. It has been used as a biomarker to measure oxidative stress in various biological samples in patients who are affected by a wide range of diseases. The aim of our work is to provide an updated overview of the role of MDA as a marker of oxidative stress in allergy-related diseases. We considered studies involving both paediatric and adult patients affected by rhinitis, asthma, urticaria and atopic dermatitis. The measurement of MDA was performed on different types of samples. The reported data highlight the role of serum MDA in inflammatory airway diseases. According to the literature review, the oxidative stress status in asthmatic patients, assessed via MDA determination, appears to worsen in the presence of other allergic airway diseases and in relation to the disease severity. This suggests that MDA can be a suitable marker for monitoring the disease status. However, there are several limitations in the considered studies due to the different samples used and the lack of phenotyping and description of the clinical period of patients examined. In cutaneous allergic diseases, the role of MDA is controversial because of the smallness of the studies and the heterogeneity of the samples and patients.

Metabolomics identifies disturbances in arginine, phenylalanine, and glycine metabolism as differentiating features of exacerbating atopic asthma in children

Background

Asthma exacerbations are highly prevalent in children, but only a few studies have examined the biologic mechanisms underlying exacerbations in this population.

Objective

High-resolution metabolomics analyses were performed to understand the differences in metabolites in children with exacerbating asthma who were hospitalized in a pediatric intensive care unit for status asthmaticus. We hypothesized that compared with a similar population of stable outpatients with asthma, children with exacerbating asthma would have differing metabolite abundance patterns with distinct clustering profiles.

Methods

A total of 98 children aged 6 through 17 years with exacerbating asthma (n = 69) and stable asthma (n = 29) underwent clinical characterization procedures and submitted plasma samples for metabolomic analyses. High-confidence metabolites were retained and utilized for pathway enrichment analyses to identify the most relevant metabolic pathways that discriminated between groups.

Results

In all, 118 and 131 high-confidence metabolites were identified in positive and negative ionization mode, respectively. A total of 103 unique metabolites differed significantly between children with exacerbating asthma and children with stable asthma. In all, 8 significantly enriched pathways that were largely associated with alterations in arginine, phenylalanine, and glycine metabolism were identified. However, other metabolites and pathways of interest were also identified.

Conclusion

Metabolomic analyses identified multiple perturbed metabolites and pathways that discriminated children with exacerbating asthma who were hospitalized for status asthmaticus. These results highlight the complex biology of inflammation in children with exacerbating asthma and argue for additional studies of the metabolic determinants of asthma exacerbations in children because many of the identified metabolites of interest may be amenable to targeted interventions.

Amino Acids in Health and Disease: The Good, the Bad, and the Ugly

The Special Issue "Amino Acid Metabolism and Regulation in Health and Disease 2 [...].

Homoarginine in health and disease

PURPOSE OF REVIEW

Homoarginine (hArg) is an endogenous, nonproteinogenic amino acid. It is enzymatically synthesized from L-arginine and L-lysine. Low hArg concentrations appear to be a risk factor in the renal and cardiovascular systems. This review discusses advances in-vitro and in-vivo experimental and clinical research on hArg in health and disease.

RECENT FINDINGS

Recent studies indicate that low circulating and low urinary concentrations of hArg are associated with morbidity and worse outcome. Although the biological activities of hArg remain still unexplored, hArg supplementation is intensely investigated as a strategy to increase hArg concentration to reach normal levels in cases of low hArg concentrations. The greatest changes in circulating hArg concentrations are observed during pregnancy and after delivery. In healthy adults, a daily dose of 125 mg hArg seems to be optimum to normalize circulating levels. Short-term supplementation of inorganic nitrate enhances hArg biosynthesis in healthy young men. Apart from hArg supplementation, dietary L-arginine and L-citrulline appear to be a promising alternative.

SUMMARY

Considerable progress has been made in recent years, but hArg remains still enigmatic. Further research is required to explore the biological activities of hArg. Supplementation of hArg or its precursors L-citrulline/L-arginine seem to be promising strategies to prevent and overcome altered hArg synthesis.