IL-33/Vitamin D Crosstalk in Psoriasis-Associated Osteoporosis

Targeting bone homeostasis regulation: potential of traditional Chinese medicine flavonoids in the treatment of osteoporosis

Osteoporosis is a systemic metabolic disease characterized by disrupted bone formation/resorption and homeostasis. Flavonoids extracted from traditional Chinese medicinal plants regulate bone homeostasis by intervening in differentiating bone marrow mesenchymal stem cells, balancing the bone immune system, inhibiting oxidative stress response, and reversing iron overload. The target molecules and signaling pathways, such as Wnt/β-catenin and OPG/RANKL/RANK, directly affect osteoblast/osteoclast activity, exhibiting significant potential in the treatment of OP. Therefore, this study presents a systematic review of the recent literature to provide comprehensive information on the traditional Chinese medicine flavonoids involved in the regulation of bone homeostasis. Also, the molecular mechanisms and pharmacological uses of these metabolites are summarized, and their clinical translation and development potential are discussed.

Global Publication Trends and Research Hotspots of the Immune System and Osteoporosis: A Bibliometric and Visualization Analysis from 2012 to 2022

BACKGROUND

Osteoporosis (OP) is a systemic bone metabolism disorder in which the immune system and bone metabolism interact.

OBJECTIVE

The purpose of this study was to explore the research status, hot spots and trends regarding the influence of the immune system on OP and to provide a basis for research directions and applications in this field.

METHODS

We searched and collected literature about the immune system and OP published from 2012 to 2022 in the Web of Science Core Collection database. All the included studies were subjected to bibliometrics analysis using Hiplot Pro, VOSviewer and CiteSpace software to produce statistics and visual analyses of the literature output, countries, institutions, authors, keywords and journals.

RESULTS

A total of 1201 papers were included, and the number of citations of these articles reached 31,776. The number of publications and citations on the immune system and OP has increased year by year. The top three countries with the greatest number of papers published were China, the United States of America (USA) and Italy. The two institutions with the largest number of papers published were Sichuan University and Soochow University, both located in China. De Martinis Massimo (Italy) and Ginaldi Lia (Italy) are prolific authors in this field. The representative academic journals are Osteoporosis International, Frontiers in Immunology, Journal of Bone and Mineral Research, PloS One and Bone. The results of the keyword cooccurrence analysis showed that the research topics in this field mainly focused on T cells, cytokines, signaling pathways, vitamin D, postmenopausal OP and immune diseases. The keyword burst results showed that zoledronic acid, chain fatty acids and gut microbiota are the frontiers and trends of future research on this topic.

CONCLUSION

The influence of the immune system on OP has been widely studied, and the current research in this field focuses on the effect or mechanism of immune-related cytokines, signaling pathways and vitamin D on OP. Future research trends in this field should focus on the immune regulation mechanism and clinical transformation of zoledronic acid, chain fatty acids and the gut microbiota in OP.

Vitamin D Influences the Activity of Mast Cells in Allergic Manifestations and Potentiates Their Effector Functions against Pathogens

Mast cells (MCs) are abundant at sites exposed to the external environment and pathogens. Local activation of these cells, either directly via pathogen recognition or indirectly via interaction with other activated immune cells and results in the release of pre-stored mediators in MC granules. The release of these pre-stored mediators helps to enhance pathogen clearance. While MCs are well known for their protective role against parasites, there is also significant evidence in the literature demonstrating their ability to respond to viral, bacterial, and fungal infections. Vitamin D is a fat-soluble vitamin and hormone that plays a vital role in regulating calcium and phosphorus metabolism to maintain skeletal homeostasis. Emerging evidence suggests that vitamin D also has immunomodulatory properties on both the innate and adaptive immune systems, making it a critical regulator of immune homeostasis. Vitamin D binds to its receptor, called the vitamin D receptor (VDR), which is present in almost all immune system cells. The literature suggests that a vitamin D deficiency can activate MCs, and vitamin D is necessary for MC stabilization. This manuscript explores the potential of vitamin D to regulate MC activity and combat pathogens, with a focus on its ability to fight viruses.

The effect of cytokines on osteoblasts and osteoclasts in bone remodeling in osteoporosis: a review

The complicated connections and cross talk between the skeletal system and the immune system are attracting more attention, which is developing into the field of Osteoimmunology. In this field, cytokines that are among osteoblasts and osteoclasts play a critical role in bone remodeling, which is a pathological process in the pathogenesis and development of osteoporosis. Those cytokines include the tumor necrosis factor (TNF) family, the interleukin (IL) family, interferon (IFN), chemokines, and so on, most of which influence the bone microenvironment, osteoblasts, and osteoclasts. This review summarizes the effect of cytokines on osteoblasts and osteoclasts in bone remodeling in osteoporosis, aiming to providing the latest reference to the role of immunology in osteoporosis.

The influence of vitamin D supplementation on the expression of mediators of inflammation in knee osteoarthritis

This trial aimed to determine the possible therapeutic and immunomodulatory effects of vitamin D3 in patients with knee OA. In this open-label clinical trial, symptoms were assessed over 3 months in patients with primary knee OA receiving oral vitamin D3 4000 IU/day. Clinical response was evaluated at baseline and 3 months using WOMAC subscores and VAS. Serum levels of cytokines IL-1β, TNF-α, IL-13, IL-17, IL-33, IL-4, and IL-10 were determined by ELISA method. Eighty patients with knee OA were included. All 80 completed the study; the median 25(OH)D3 level was 23.1 ng/ml at baseline and increased by 12.3 ng/ml after treatment. Vitamin D3 after 3 months of supplementation induced a significant reduction in VAS pain and WOMAC subscores. Using OMERACT-OARSI criteria, 86.7% of patients treated with vitamin D3 responded to treatment. At the end of 3 months, systemic values of IL-1β (p < 0.01), IL-23 (p < 0.01), and IL-33 (p < 0.01) were significantly increased, values of TNF-α (p < 0.01), IL-13 (p < 0.01), and IL-17 (p < 0.01) were significantly decreased, while value of IL-4 was not significantly changed. No adverse events were detected. Treatment with vitamin D is associated with improvement in pain, as well as stiffness and physical function. Vitamin D supplementation increased systemic values of IL-33. Our results indicate that vitamin D3 supplementation may be used as a novel therapeutic in knee OA. Future studies are needed to investigate a potential role of IL-33 in the pathogenesis of knee OA.

Impact of Chronic Inflammation in Psoriasis on Bone Metabolism

Psoriasis is a chronic inflammatory disease of the skin and joints associated with several comorbidities such as arthritis, diabetes mellitus and metabolic syndrome, including obesity, hypertension and dyslipidaemia, Crohn's disease, uveitis and psychiatric and psychological diseases. Psoriasis has been described as an independent risk factor for cardiovascular diseases and thus patients with psoriasis should be monitored for the development of cardiovascular disease or metabolic syndrome. However, there is mounting evidence that psoriasis also affects the development of osteoporosis, an important metabolic disease with enormous clinical and socioeconomic impact. At present, there are still controversial opinions about the role of psoriasis in osteoporosis. A more in depth analysis of this phenomenon is of great importance for affected patients since, until now, bone metabolism is not routinely examined in psoriatic patients, which might have important long-term consequences for patients and the health system. In the present review, we summarize current knowledge on the impact of psoriatic inflammation on bone metabolism and osteoporosis.

Osteoporosis in patients with rheumatoid arthritis is associated with serum immune regulatory cellular factors

OBJECTIVE

Osteoporosis (OP) is a comorbidity of rheumatoid arthritis (RA) that largely causes disability. This study discussed the expression patterns of serum immunoregulatory factors and their clinical significance in RA patients complicated with OP.

METHODS

A total of 116 RA patients were enrolled. Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry to allocate patients to OP group (N = 62) and non-OP group (N = 54). CRP, rheumatoid factor, IgG, IgA, and IgM were detected using rate nephelometry. Erythrocyte sedimentation rate (ESR) and bone metabolic indexes were detected using Microsed automatic ESR analyzer and Cobas e601 automated immunoassay systems and reagents. IL-17, IL-6, TNF-α, IL-10, and IL-4 levels were determined using ELISA kit and their prediction values on OP were analyzed using the ROC curve. Influencing factors of OP incidence were analyzed using logistic regression model.

RESULTS

RA patients with OP showed increased age, disease course, tender and swollen joints, ESR, CRP, DAS28 scores, β-CTX, IL-17, IL-6, and TNF-α, and decreased 25(OH)D3, IL-10, and IL-4. DAS28 was positively correlated with IL-17, IL-6, and TNF-α, and negatively correlated with IL-10 and IL-4. DAS28, IL-17, IL-10, and IL-4 were independently correlated with OP in RA patients. The combination of DAS28, IL-17, IL-10, and IL-4 can better predict the incidence of OP complication in RA patients.

CONCLUSION

IL-17, IL-6, TNF-α, IL-10, and IL-4 were associated with disease activity of RA patients complicated with OP. A combination of DAS28, IL-17, IL-10, and IL-4 might predict OP incidence in RA patients.

The Microbiota-Bone-Allergy Interplay

Emerging knowledge suggests an increasing importance of gut microbiota in health and disease. Allergy and bone metabolism are closely interconnected, and the possible negative effects of common therapies are not the only aspects of this relationship. The immune system is influenced by the microbiota-host interactions, and several pieces of evidence suggest the existence of an interplay between microbiota, bone metabolism, and allergies. Understanding these inter-relationships is essential for the development of new potential strategies of treatment and prevention targeting microbiota. A wide range of substances and germs, prebiotics and probiotics, are capable of influencing and modifying the microbiota. Prebiotics and probiotics have been shown in several studies to have different actions based on various factors such as sex, hormonal status, and age. In this review, we summarize the latest knowledge on the topic, and we discuss practical implications and the need for further studies.

Extra-Articular Manifestations and Comorbidities in Psoriatic Disease: A Journey Into the Immunologic Crosstalk

Psoriatic arthritis (PsA) is a chronic inflammatory disease primarily affecting peripheral and axial joints, with the possible presence of extra-articular manifestations (EAMs), such as psoriasis, uveitis, and inflammatory bowel disease. Recently, the concept of psoriatic disease (PsD) has been proposed to define a systemic condition encompassing, in addition to joints and EAMs, some comorbidities (e.g., metabolic syndrome, type II diabetes, hypertension) that can affect the disease outcome and the achievement of remission. EAMs and comorbidities in PsA share common immunopathogenic pathways linked to the systemic inflammation of this disease; these involve a broad variety of immune cells and cytokines. Currently, various therapeutics are available targeting different cytokines and molecules implicated in the inflammatory response of this condition; however, despite an improvement in the management of PsA, comprehensive disease control is often not achievable. There is, therefore, a big gap to fill especially in terms of comorbidities and EAMs management. In this review, we summarize the clinical aspects of the main comorbidities and EAMs in PsA, and we focus on the immunopathologic features they share with the articular manifestations. Moreover, we discuss the effect of a diverse immunomodulation and the current unmet needs in PsD.

Vitamin D and Rheumatic Diseases: A Review of Clinical Evidence

Vitamin D plays an important role in maintaining a healthy mineralized skeleton. It is also considered an immunomodulatory agent that regulates innate and adaptive immune systems. The aim of this narrative review is to provide general concepts of vitamin D for the skeletal and immune health, and to summarize the mechanistic, epidemiological, and clinical evidence on the relationship between vitamin D and rheumatic diseases. Multiple observational studies have demonstrated the association between a low level of serum 25-hydroxyvitamin D [25(OH)D] and the presence and severity of several rheumatic diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), spondyloarthropathies, and osteoarthritis (OA). Nevertheless, the specific benefits of vitamin D supplements for the treatment and prevention of rheumatic diseases are less accepted as the results from randomized clinical trials are inconsistent, although some conceivable benefits of vitamin D for the improvement of disease activity of RA, SLE, and OA have been demonstrated in meta-analyses. It is also possible that some individuals might benefit from vitamin D differently than others, as inter-individual difference in responsiveness to vitamin D supplementation has been observed in genomic studies. Although the optimal level of serum 25(OH)D is still debatable, it is advisable it is advisable that patients with rheumatic diseases should maintain a serum 25(OH)D level of at least 30 ng/mL (75 nmol/L) to prevent osteomalacia, secondary osteoporosis, and fracture, and possibly 40–60 ng/mL (100–150 nmol/L) to achieve maximal benefit from vitamin D for immune health and overall health.

Inhibition of NF-κB/IL-33/ST2 Axis Ameliorates Acute Bronchiolitis Induced by Respiratory Syncytial Virus

Background/Aim

Bronchiolitis is a common acute lower respiratory tract infectious disease in infants. Respiratory syncytial virus (RSV) infection is one of the main causes. Bronchiolitis can lead to a significant increase in the incidence of asthma in young children, but the mechanism of bronchiolitis transforming into asthma is still unclear. The study was aimed at investigating the role of NF-κB/IL-33/ST2 axis on RSV-induced acute bronchiolitis.

Methods

A total of 40 infants diagnosed with acute bronchiolitis infected by RSV, and 20 normal infants were included in this study. BALB/c mice (6-8 weeks old, 20 ± 1.1 g) were used as study models. Enzyme-linked immunosorbent assay (ELISA), quantitative real time PCR, western blot analysis, immunohistochemical staining, and flow cytometry analysis were performed to examine relevant indicators.

Results

IL-33 level was significantly elevated, and Th1/Th2 ratio is imbalance after in infants with acute bronchiolitis. In vivo study, we found that NF-κB/IL-33/ST2 axis is mediated the Th2 cytokine levels and BAL cell number induced by RSV. Acute bronchiolitis induced by RSV in a mouse model is attenuated after inhibition of NF-κB/IL-33/ST2 pathway. Moreover, we also confirmed that macrophages are important sources of IL-33 and are regulated by NF-κB pathway in RSV-induced mice.

Conclusion

We confirmed that inhibition of NF-κB/IL-33/ST2 axis could attenuate acute bronchiolitis by RSV infected. Our findings not only demonstrate the potential role of IL-33 antibody in attenuating RSV-induced lung damage but also provide a new insight into better prevention of RSV-induced asthma by mediating NF-κB/IL-33/ST2 axis.

Reviewing the Significance of Vitamin D Substitution in Monoclonal Gammopathies

Vitamin D is a steroid hormone that is essential for bone mineral metabolism and it has several other effects in the body, including anti-cancer actions. Vitamin D causes a reduction in cell growth by interrupting the cell cycle. Moreover, the active form of vitamin D, i.e., 1,25-dihydroxyvitamin D, exerts various effects via its interaction with the vitamin D receptor on the innate and adaptive immune system, which could be relevant in the onset of tumors. Multiple myeloma is a treatable but incurable malignancy characterized by the growth of clonal plasma cells in protective niches in the bone marrow. In patients affected by multiple myeloma, vitamin D deficiency is commonly correlated with an advanced stage of the disease, greater risk of progression, the development of pathological fractures, and a worse prognosis. Changes in the vitamin D receptor often contribute to the occurrence and progress of deficiencies, which can be overcome by supplementation with vitamin D or analogues. However, in spite of the findings available in the literature, there is no clear standard of care and clinical practice varies. Further research is needed to better understand how vitamin D influences outcomes in patients with monoclonal gammopathies.