Skin Inflammation and Testicular Function: Dermatitis Causes Male Infertility via Skin-Derived Cytokines

Amelioration of Systemic Amyloidosis by Blocking IL-17A and Not by IL-17F, and Arteriosclerosis by Blocking Both IL-17A and IL-17F in an Inflammatory Skin Mouse Model

There are comorbidities and complications in atopic dermatitis and psoriasis that often occur after the appearance of skin inflammation. Statistically, data show that patients with psoriasis and atopic dermatitis have a shorter life expectancy than patients without psoriatic dermatitis, due to the occurrence of arteriosclerosis, myocardial infarction, and cerebral infarction. Many types of skin inflammation are treated with various antibody preparations, and marked improvement in patients' quality of life can be achieved. The next theme is to understand the pathogenesis of arteriosclerosis, myocardial infarction, stroke, and other complications associated with dermatitis and to find treatments and drugs to reduce their occurrence. The skin, a crucial immune organ, generates large amounts of inflammatory cytokines in response to various stimuli, leading to systemic inflammation and potential damage to internal organs. The link between inflammatory skin conditions like psoriasis and atopic dermatitis with serious health complications such as vascular disorders and systemic amyloidosis has been increasingly recognized. In psoriasis, biological treatments targeting Interleukin (IL)-17A, a key cytokine, have shown promise in reducing cardiovascular risks. Recent developments include treatments that target both IL-17A and IL-17F in the psoriasis field, though each cytokine's impact on internal organ damage is still under debate. Among visceral complications secondary to dermatitis, systemic amyloidosis and atherosclerosis have been reported to be controlled by suppressing IL-17 in the early stages of dermatitis. Still, it remains unclear whether suppressing IL-17 prevents organ damage in the late stages of persistent severe dermatitis. A study using a long-lasting dermatitis mouse model that overexpressed human caspase-1 in keratinocytes (Kcasp1Tg) investigated the effects of deleting IL-17A and IL-17F on visceral complications. Cross-mating Kcasp1Tg with IL-17A-, IL-17F-, and IL-17AF-deficient mice assessed the skin and visceral organs histologically, and RT-PCR analysis of aortic sclerosis markers was performed. Despite less improvement in dermatitis, deletion of IL-17A in Kcasp1Tg mice showed promising results in reducing multiple organ amyloidosis. On the other hand, the effect was observed in both IL-17A and IL-17F deleted mice for aortic sclerosis. The inhibition of IL-17A and IL-17F was suggested to reduce the risk of developing comorbidities in internal organs. IL-17A and IL-17F were found to act similarly or produce very different results, depending on the organ.

Tissue engineering studies in male infertility disorder

Infertility is an important issue among couples worldwide which is caused by a variety of complex diseases. Male infertility is a problem in 7% of all men. In vitro spermatogenesis (IVS) is the experimental approach that has been developed for mimicking seminiferous tubules-like functional structures in vitro. Currently, various researchers are interested in finding and developing a microenvironmental condition or a bioartificial testis applied for fertility restoration via gamete production in vitro. The tissue engineering (TE) has developed new approaches to treat male fertility preservation through development of functional male germ cells. This makes TE a possible future strategy for restoration of male fertility. Although 3D culture systems supply the perception of the effect of cellular interactions in the process of spermatogenesis, formation of a native gradient of autocrine/paracrine factors in 3D culture systems have not been considered. These results collectively suggest that maintaining the microenvironment of testicular cells even in the form of a 3D-culture system is crucial in achieving spermatogenesis ex vivo. It is also possible to engineer the testicular structures using biomaterials to provide a supporting scaffold for somatic and stem cells. The insemination of these cells with GFs is possible for temporally and spatially adjusted release to mimic the microenvironment of the in situ seminiferous epithelium. This review focuses on recent studies and advances in the application of TE strategies to cell-tissue culture on synthetic or natural scaffolds supplemented with growth factors.

Inflammatory Skin Disease Causes Anxiety Symptoms Leading to an Irreversible Course

Intense itching significantly reduces the quality of life, and atopic dermatitis is associated with psychiatric conditions, such as anxiety and depression. Psoriasis, another inflammatory skin disease, is often complicated by psychiatric symptoms, including depression; however, the pathogenesis of these mediating factors is poorly understood. This study used a spontaneous dermatitis mouse model (KCASP1Tg) and evaluated the psychiatric symptoms. We also used Janus kinase (JAK) inhibitors to manage the behaviors. Gene expression analysis and RT-PCR of the cerebral cortex of KCASP1Tg and wild-type (WT) mice were performed to examine differences in mRNA expression. KCASP1Tg mice had lower activity, higher anxiety-like behavior, and abnormal behavior. The mRNA expression of S100a8 and Lipocalin 2 (Lcn2) in the brain regions was higher in KCASP1Tg mice. Furthermore, IL-1β stimulation increased Lcn2 mRNA expression in astrocyte cultures. KCASP1Tg mice had predominantly elevated plasma Lcn2 compared to WT mice, which improved with JAK inhibition, but behavioral abnormalities in KCASP1Tg mice did not improve, despite JAK inhibition. In summary, our data revealed that Lcn2 is closely associated with anxiety symptoms, but the anxiety and depression symptoms caused by chronic skin inflammation may be irreversible. This study demonstrated that active control of skin inflammation is essential for preventing anxiety.

Arteriosclerosis Derived from Cutaneous Inflammation Is Ameliorated by the Deletion of IL-17A and IL-17F

The skin is one of the major immune organs producing large amounts of proinflammatory and inflammatory cytokines in response to internal or exogenous stimuli, inducing systemic inflammation in various internal organs. In recent years, organ damage associated with inflammatory skin diseases such as psoriasis and atopic dermatitis has received increasing attention, and vascular disorder such as arteriosclerosis is one of the serious complications of chronic inflammatory skin diseases. However, the detailed mechanism of arteriosclerosis in dermatitis and the role of cytokines have not been clarified so far. In the current study, using a spontaneous dermatitis model, we investigated the pathophysiology of arteriosclerosis and the treatment option for inflammatory skin conditions. We employed spontaneous dermatitis model mice overexpressing human caspase-1 in the epidermal keratinocyte (Kcasp1Tg). The thoracic and abdominal aorta was investigated histologically. GeneChip and RT-PCR analysis were performed to measure the changes in mRNA levels in the aorta. To elucidate the direct effect on the artery by major inflammatory cytokines, endothelial cells, vascular smooth muscle cells, and fibroblast cells were co-cultured with several cytokines, and mRNA expression levels were measured. In order to observe the efficacy of IL-17A/F in arteriosclerosis, cross-mating with IL-17A, IL-17F, and IL-17A/F deficient mice was performed. Finally, we also measured snap tension in the abdominal aorta in WT, Kcasp1Tg, and IL17A/F-deficient mice. Kcasp1Tg showed a decrease in the diameter of the abdominal aorta compared to wild-type mice. mRNA levels for six genes including Apol11b, Camp, Chil3, S100a8, S100a9, and Spta1 were increased in the abdominal aorta of Kcasp1Tg. Some of the above mRNA levels were also increased in the co-culture with major inflammatory cytokines, IL-17A/F, IL-1β, and TNF-α. Dermatitis improved and mRNA levels were partially ameliorated in Kcasp1Tg with IL-17A/F deletion. Arterial fragility was also evidenced in the inflammatory model, but arterial flexibility was revealed in the IL-17A/F deletion model. Severe dermatitis is closely related to secondary arteriosclerosis caused by the persistent release of inflammatory cytokines. The results also proved that treatment against IL-17A and F may ameliorate arteriosclerosis.

The Interplay of Type 1, Type 2, and Type 3 Lymphocytes and Cytokines in Atopic Dermatitis

Atopic dermatitis (AD) is classified as a type 2 disease owing to the majority of type 2 lymphocytes that constitute the skin-infiltrating leukocytes. However, all of the type 1-3 lymphocytes intermingle in inflamed skin lesions. Here, using an AD mouse model where caspase-1 was specifically amplified under keratin-14 induction, we analyzed the sequential changes in type 1-3 inflammatory cytokines in lymphocytes purified from the cervical lymph nodes. Cells were cultured and stained for CD4, CD8, and γδTCR, followed by intracellular cytokines. Cytokine production in innate lymphocyte cells (ILCs) and the protein expression of type 2 cytokine IL-17E (IL-25) were investigated. We observed that, as inflammation progresses, the cytokine-producing T cells increased and abundant IL-13 but low levels of IL-4 are produced in CD4-positive T cells and ILCs. TNF-α and IFN-γ levels increased continuously. The total number of T cells and ILCs peaked at 4 months and decreased in the chronic phase. In addition, IL-25 may be simultaneously produced by IL-17F-producing cells. IL-25-producing cells increased in a time-dependent manner during the chronic phase and may work specifically for the prolongation of type 2 inflammation. Altogether, these findings suggest that inhibition of IL-25 may be a potential target in the treatment of inflammation.

Treatment in Patients with Psoriatic Disease and Rheumatoid Arthritis: Seven Case Reports

The incidence of psoriasis, an intractable long-lasting inflammatory skin disease, is increasing and has many complications and comorbidities. Approximately 14% of patients have psoriatic arthritis (PsA). Rheumatoid arthritis (RA) is not a rare disease worldwide, and some patients may have both PsA and RA. In the present study, we encountered seven patients with concurrent diagnoses of RA and psoriatic disease and reported the details of clinical data, treatment efficacy, and X-ray findings. The diagnosis may require not only classification criteria but also a comprehensive judgment in collaboration with rheumatology over time. In addition to methotrexate as an anchor drug, anti-tumor necrosis factor-α agents are the first choice of biological agents for treatment, and interleukin (IL)-17 inhibitors may be effective, as IL-17 is also involved in the pathogenesis of RA. When treating patients with both PsA and RA, it may be essential to consider the treatment strategy, depending on which disease is more active.

IL-17A Is the Critical Cytokine for Liver and Spleen Amyloidosis in Inflammatory Skin Disease

Systemic amyloidosis is recognized as a serious complication of rheumatoid arthritis or inflammatory bowel disease, but also of inflammatory skin disease. However, the detailed molecular mechanism of amyloidosis associated with cutaneous inflammation remains unclear, and therapeutic approaches are limited. Here, we investigated the pathophysiology of amyloidosis secondary to cutaneous inflammation and the therapeutic effects of Janus kinase (JAK) inhibitors by examining a mouse model of spontaneous dermatitis (KCASP1Tg mice). Moreover, KCASP1Tg mice were crossed with interleukin-17A (IL-17A) knockout mice to generate IL-17A-/KCASP1Tg and examine the role of IL-17A in amyloidosis under cutaneous inflammation. KCASP1Tg mice showed severe amyloid deposition in the liver and spleen. Increased serum-neutral fat levels and decreased lymphocyte production were observed in the spleen. Overproduction of amyloidosis was partially ameliorated by the administration of JAK inhibitors and was further improved in IL-17A-/KCASP1Tg mice. IL-17A-producing cells included CD4, gamma delta, and CD8 T cells. In summary, our results from the analysis of a mouse model of dermatitis revealed that skin-derived inflammatory cytokines can induce amyloid deposition in the liver and spleen, and that the administration of JAK inhibitors and, even more, IL-17A ablation, reduced amyloidosis. This study demonstrates that active control of skin inflammation is essential to prevent internal organ amyloidosis.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection by Intranasal or Intratesticular Route Induces Testicular Damage

BACKGROUND

The role of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the pathogenesis of testicular damage is uncertain.

METHODS

We investigated the virological, pathological, and immunological changes in testes of hamsters challenged by wild-type SARS-CoV-2 and its variants with intranasal or direct testicular inoculation using influenza virus A(H1N1)pdm09 as control.

RESULTS

Besides self-limiting respiratory tract infection, intranasal SARS-CoV-2 challenge caused acute decrease in sperm count, serum testosterone and inhibin B at 4-7 days after infection; and chronic reduction in testicular size and weight, and serum sex hormone at 42-120 days after infection. Acute histopathological damage with worsening degree of testicular inflammation, hemorrhage, necrosis, degeneration of seminiferous tubules, and disruption of orderly spermatogenesis were seen with increasing virus inoculum. Degeneration and death of Sertoli and Leydig cells were found. Although viral loads and SARS-CoV-2 nucleocapsid protein expression were markedly lower in testicular than in lung tissues, direct intratesticular injection of SARS-CoV-2 demonstrated nucleocapsid expressing interstitial cells and epididymal epithelial cells, While intranasal or intratesticular challenge by A(H1N1)pdm09 control showed no testicular infection or damage. From 7 to 120 days after infection, degeneration and apoptosis of seminiferous tubules, immune complex deposition, and depletion of spermatogenic cell and spermatozoa persisted. Intranasal challenge with Omicron and Delta variants could also induce similar testicular changes. This testicular damage can be prevented by vaccination.

CONCLUSIONS

SARS-CoV-2 can cause acute testicular damage with subsequent chronic asymmetric testicular atrophy and associated hormonal changes despite a self-limiting pneumonia in hamsters. Awareness of possible hypogonadism and subfertility is important in managing convalescent coronavirus disease 2019 in men.

Janus Kinase Inhibitors Ameliorated Gastrointestinal Amyloidosis and Hypoalbuminemia in Persistent Dermatitis Mouse Model

Malnutrition is not only regarded as a complication of rheumatoid arthritis and inflammatory bowel disease but also that of inflammatory skin disease; however, the mechanisms and efficacy of its treatment have not been elucidated. Using a mouse model of dermatitis, we investigated the pathophysiology of malnutrition in inflammatory skin conditions and efficacy of its treatment. We employed spontaneous skin inflammation mice models overexpressing human caspase-1 in the epidermal keratinocytes. Body weight, nutrition level, and α1-antitrypsin fecal concentration were measured. The gastrointestinal tract was histologically and functionally investigated. Fluorescein isothiocyanate (FITC)-dextran was forcibly fed on an empty stomach, and plasma FITC-dextran was measured. The treatment efficacy of antibodies against tumor necrosis factor-α (TNF-α) and interleukin (IL)-α/β as well as Janus kinase (JAK) inhibitors was investigated. Compared with wild-type littermates, the inflammatory skin mice models showed a lowered body weight, reduction of serum albumin level, amyloid deposition in the stomach, small intestine, and large intestine, and increased α1-antitrypsin fecal concentration. However, the plasma FITC-dextran was unchanged between the dermatitis models and wild-type littermates. The over-produced serum amyloid A1 in the liver was detected in the plasma in the dermatitis model. Antibodies against TNF-α and IL-α/β showed partial effects on amyloid deposition; however, JAK inhibitors improved gastrointestinal amyloidosis with the improvement of skin symptoms. Chronic dermatitis is closely related to secondary amyloidosis in the gastrointestinal tract, resulting in hypoalbuminemia. Therefore, active control of skin inflammation is essential for preventing gastrointestinal complications.