Tomoharu Yokooji

Long-term l-3,4-dihydroxyphenylalanine (l-DOPA) therapy for Parkinson’s disease increases plasma concentrations of 3-O-methyldopa (3-OMD), a major metabolite of l-DOPA. This study aimed to investigate the role of 3-OMD in the central nervous system (CNS)-mediated behavioral effects associated with chronic l-DOPA treatment in rats. The effects of 3-OMD on CNS function were examined using two rat models: repeated oral co-administration of l-DOPA/benserazide and single or repeated intraperitoneal (i.p.) administration of 3-OMD. Behavioral assessments included spontaneous locomotor activity, spontaneous alternation behavior (SAB), spatial learning, and depression-like behavior. Plasma and brain concentrations of 3-OMD were also measured. Repeated oral administration of l-DOPA/benserazide maintained plasma 3-OMD concentrations at 1.57–3.50 μg/mL and brain concentrations at 1.68–3.23 μg/g. This treatment reduced SAB by up to 30% and showed a trend toward reduced spatial learning, whereas locomotor activity was unaffected. Repeated i.p. administration of 3-OMD produced comparable plasma and brain concentrations of 3-OMD, reduced SAB, and showed a trend toward reduced spatial learning, without affecting other behaviors. The reduction in SAB was reversed after a 7-d washout period. In contrast, a single administration of 3-OMD had no detectable behavioral effects. In conclusion, sustained, but not transient, exposure to 3-OMD may contribute to reduced working memory performance during chronic l-DOPA therapy.

Nonsteroidal anti-inflammatory drugs have been reported to enhance oral sensitization to food allergens, potentially through disruption of the intestinal epithelial barrier. Epithelial-derived cytokines, including thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25, promote immunoglobulin E (IgE) production by inducing T helper type 2 immune responses and may contribute to allergen sensitization following epithelial injury. This study aimed to investigate oral sensitization to ovalbumin (OVA) in a rat model of intestinal epithelial injury induced by dextran sulfate sodium (DSS) or indomethacin (IND), focusing on the involvement of TSLP in relation to the anatomical site of epithelial injury. Rats were orally immunized with OVA by gavage every other day for 6 weeks. DSS was administered in drinking water from 2 weeks before immunization, whereas IND was administered orally at a dose of 6 mg/kg 30 min before each OVA administration. To explore the involvement of TSLP, anti-TSLP antibodies were administered intraperitoneally once a week throughout the immunization period. Histological analysis showed that DSS induced epithelial injury in both the jejunum and proximal colon, whereas IND caused milder epithelial injury limited to the jejunum. Plasma OVA-specific IgE (OVA-sIgE) levels were elevated in both models. Anti-TSLP antibody treatment attenuated DSS-enhanced OVA-sIgE production, but had limited effects in the IND model. In conclusion, intestinal epithelial injury may enhance oral sensitization through mechanisms that differ according to the anatomical site and extent of injury. TSLP appears to contribute predominantly to sensitization associated with epithelial damage involving both the jejunum and proximal colon.

Sensitisation leading to food allergy may occur through the skin. Quantitative data on epidermal allergen penetration as a prerequisite for this remain limited. This study quantifies epidermal penetration of gluten and hydrolysed wheat protein (HWP) in 18 patients with challenge-confirmed WALDA (wheat allergy dependent on augmentation factors) and 12 healthy controls (HC). After 1 h of epicutaneous wheat application, 20 consecutive tape strips (TS) were collected, and wheat protein concentration was quantified by gliadin-specific ELISA. Skin barrier status was assessed by electrical impedance spectroscopy (EIS). Serum gliadin levels were measured before and 90 min after wheat application. Gliadin was detected across all TS layers for gluten and HWP. Penetration levels did not differ between patients and controls. Skin barrier status assessed by EIS did not differ significantly between individuals with and without a history of atopic dermatitis (p = 0.27). No correlation was observed between EIS-assessed skin barrier status and gliadin penetration. Serum gliadin was not increased after epicutaneous wheat application. This study using TS demonstrates for the first time that wheat allergens penetrated into the epidermis but could not be detected in the serum. Neither wheat allergy nor skin barrier status was associated with increased stratum corneum penetration. These findings suggest that epidermal uptake alone may not be sufficient to explain sensitisation.

Transplantation of adipose-derived mesenchymal stromal/stem cells (ASCs) has successfully alleviated the severity of psoriasis. Although several therapeutic mechanisms of mesenchymal stromal/stem cells (MSCs) for psoriasis have been elucidated using the imiquimod (IMQ)-induced psoriasis-like dermatitis model, the effects of MSC transplantation on pathways other than the interleukin (IL)-23/T helper 17 (Th17) axis, including the IL-36 pathway, remain unclear. In this study, we aimed to investigate the efficacy of ASC transplantation for the IMQ-induced psoriasis-like dermatitis in male C57BL/6J mice, and to elucidate its effects on the IL-36 pathway as well as the IL23/Th17 axis. ASCs (2.0 × 106 cells) from mouse inguinal white adipose tissue were subcutaneously injected into the dorsal skin of mice. After the topical application of IMQ cream for 5 consecutive days, objective severity scores, cytokine gene expression levels, and neutrophil infiltration grade were determined to evaluate their efficacy. Anti-IL-23p19 antibody treatment was used for comparison. ASCs slightly ameliorated IMQ-induced epidermal thickening, although anti-IL-23p19 antibodies had no effect on any skin manifestations. Anti-IL-23p19 antibody and ASC suppressed the expressions of Il17a, Il17f, and Il22 mRNAs and neutrophil infiltration in IMQ-applied skin, but not the expression of Il1f6 and Il1f9. ASC also suppressed the expressions of Il23, Il6, Il1b, Tnfa, Lipocalin-2, and Cxcl5 mRNAs, which were not suppressed by anti-IL-23p19 antibody treatment. In conclusion, ASC transplantation suppressed activation of the IL-23/Th17 axis and neutrophil infiltration, and inhibited the activation of a broader range of inflammatory mediators except for IL-36 expression in IMQ-applied skin compared with anti-IL-23p19 antibody treatment.

Oral immunotherapy (OIT) is a promising approach for treating food allergy. Here, we elucidated the mechanisms of desensitization induced by OIT in rats sensitized to ovalbumin (OVA). The desensitization was induced by ingestion of OVA three times per week after sensitization in rats. OIT suppressed the decrease in rectal temperature and increase in plasma histamine levels induced by OVA injection immediately and 4 weeks after OIT completion. Plasma OVA-specific IgE (sIgE) levels did not differ between the non-OIT and OIT groups, but OVA-specific IgG₁ levels were higher in the OIT group than in the non-OIT group at both timepoints. To evaluate IgG’s effect on IgE crosslinking with OVA, amplified luminescence proximity homogeneous assay involving crosslinking (AlphaCL) was performed. When IgG was removed using a Protein G column, the AlphaCL signal was significantly increased, especially in the OIT group, indicating that OIT-induced IgG inhibited the sIgE response. The proportions of cluster of differentiation (CD)4⁺ cells and CD4⁺CD25⁺FoxP3⁺ cells in mesenteric lymph nodes and spleen were similar between the two groups. These findings indicate that OIT attenuates systemic allergic responses by inhibiting sIgE binding to OVA through increased IgG. Our model is useful for understanding the mechanisms of OIT and optimizing therapeutic strategies for ameliorating food allergies.

Despite the high frequency of pregnancies complicated by abnormal glucose metabolism associated with obesity, methylmercury (MeHg) metabolism in pregnant women with abnormal glucose metabolism is unclear. We aimed to elucidate the MeHg tissue distribution in obese female mice with abnormal glucose metabolism and their fetuses. Female C57BL/6J mice were fed a high‐fat diet (HFD) or a standard diet (Ctrl) for 12 weeks and mated. HFD mice showed mild glucose metabolism abnormalities as assessed by an oral glucose tolerance test. Maternal tissues (brain, liver, and kidney) and blood (plasma and blood cells) and fetal tissues (brain, liver, kidney, and placenta) were collected from these mice 24 h after oral administration of MeHg (a single dose of 1 or 5 mg Hg/kg) on Day 16 of mating. The total mercury level was determined in each sample, and its distribution to each tissue was estimated using K_p values (total mercury in each tissue/total mercury in maternal plasma). The K_p values for the maternal brain and liver were lower in HFD mice than in Ctrl mice, but no significant difference between groups was observed in the kidney or blood cells. The K_p values for all fetal tissues were lower in HFD mice than in Ctrl mice. Pregnant mice showed higher K_p values for the brain and lower K_p values for the kidney than those in nonpregnant mice, regardless of diet. These results will provide useful information to assess the risk of MeHg in obese mothers with glucose metabolism abnormalities and their fetuses.

The specific detection of serum IgE antibodies specific to allergens (sIgE Abs) that can crosslink the plural high-affinity IgE receptor (FcεRIα) molecules on the surface of mast cells or basophils with a multivalent allergen can reduce the false-positive diagnoses observed in chemiluminescent and fluorescence enzyme immunoassays for type-I allergic patients. In this study, we detected sIgE Abs to the egg-allergen ovalbumin (OVA) and the wheat-allergen gluten in the sera of rats sensitized with each allergen using an amplified luminescence proximity homogeneous assay by crosslinking (AlphaCL). OVA and gluten were reacted with each sIgE Ab in the sera. Then, acceptor and donor beads labeled with the human FcεRIα were added to the reacted solution. The luminescence intensity for anti-OVA IgE Abs in the sera with the removal of IgG Abs was observed in five of seven (71.4%) of the sensitized rats, whereas no signals were observed in any of the unsensitized rats. The AlphaCL could also detect anti-gluten sIgE Abs in the sera of sensitized rats, but not of unsensitized rats. In conclusion, we successfully detected sIgE Abs in the sera of rats sensitized to two allergens using the AlphaCL. This detection method has the potential to be used as a new diagnostic tool for type-I allergic patients.

Immunoglobulin E (IgE)-mediated food allergies to wheat that develop after school age typically shows a type of wheat-dependent exercise-induced anaphylaxis (WDEIA). At present, avoidance of wheat products or postprandial rest after ingesting wheat is recommended for patients with WDEIA, depending on the severity of the allergy symptoms. ω5-Gliadin has been identified as the major allergen in WDEIA. In addition, α/β-, γ-, and ω1,2-gliadins, high and low molecular weight-glutenins, and a few water-soluble wheat proteins have been identified as IgE-binding allergens in a small proportion of patients with IgE-mediated wheat allergies. A variety of approaches have been manufactured to develop hypoallergenic wheat products that can be consumed by patients with IgE-mediated wheat allergies. In order to analyze such approaches, and to contribute to the further improvement, this study outlined the current status of these hypoallergenic wheat productions, including wheat lines with a reduced allergenicity that are mostly constructed for the patients sensitized to ω5-gliadin, hypoallergenic wheat by enzymic degradation/ion exchanger deamidation, and hypoallergenic wheat by thioredoxin treatment. The wheat products obtained by these approaches significantly reduced the reactivity of Serum IgE in wheat-allergic patients. However, either these were not effective on some populations of the patients, or low-level IgE-reactivity to some allergens of the products was observed in the patients. These results highlight some of the difficulties faced in creating hypoallergenic wheat products or hypoallergenic wheat lines through either traditional breeding or biotechnology approaches in developing hypoallergenic wheat completely safe for all the patients allergic to wheat.

The early ingestion of food can prevent the onset of food allergy related to inducing oral tolerance (OT). We developed the Hokushin wheat line as a hypoallergenic wheat (1BS-18H) lacking ω5-gliadin, a major allergen of wheat-dependent exercise-induced anaphylaxis (WDEIA). The 1BS-18H wheat had lower ability of sensitization for ω5-gliadin compared with Hokushin wheat. Here, we evaluated the induction of OT to gluten and ω5-gliadin by the early consecutive ingestion of 1BS-18H gluten using a rat model of wheat allergy. Rats were subcutaneously immunized with commercial gluten or native ω5-gliadin following the daily oral administration of gluten. The daily oral administration of 1BS-18H gluten for 5 days before immunization suppressed the increase in gluten- or ω5-gliadin-specific IgE and IgG₁ antibodies induced by immunization to a level similar to Hokushin gluten. Intravenous challenge with gluten or ω5-gliadin did not decrease the rectal temperature in rats with OT induced by 1BS-18H or Hokushin gluten, although it was decreased in non-OT rats. In conclusion, the early consecutive ingestion of 1BS-18H wheat before sensitization induced OT to gluten and ω5-gliadin. These findings support the benefit of 1BS-18H wheat to prevent wheat allergy including WDEIA by consecutive ingestion in humans.

Secondary lymphedema is a common complication of lymph node dissection or radiation therapy for cancer treatment. Conventional therapies such as compression sleeve therapy, complete decongestive physiotherapy, and surgical therapies decrease edema; however, they are not curative because they cannot modulate the pathophysiology of lymphedema. Recent advances reveal that the activation and accumulation of CD4+ T cells are key in the development of lymphedema. Based on this pathophysiology, the efficacy of pharmacotherapy (tacrolimus, anti-IL-4/IL-13 antibody, or fingolimod) and cell-based therapy for lymphedema has been demonstrated in animal models and pilot studies. In addition, mesenchymal stem/stromal cells (MSCs) have attracted attention as candidates for cell-based lymphedema therapy because they improve symptoms and decrease edema volume in the long term with no serious adverse effects in pilot studies. Furthermore, MSC transplantation promotes functional lymphatic regeneration and improves the microenvironment in animal models. In this review, we focus on inflammatory cells involved in the pathogenesis of lymphedema and discuss the efficacy and challenges of pharmacotherapy and cell-based therapies for lymphedema.