Construction of Seven-Membered Oxacycles Using a Rh(I)-Catalyzed Cascade C-C Formation/Cleavage of Cyclobutenol Derivatives.

Herein, we describe the synthesis of substituted oxepane derivatives through the skeletal remodeling of 4-hydroxy-2-cyclobutenones, which are readily prepared from commercially available dialkyl squarates upon their reaction with acrylonitrile. Mechanistically, a Rh(I)-catalyzed C-C bond formation and cleavage cascade is proposed. Specifically, a fused [3.2.0] bicycle is proposed to form from dialkyl squarate-derived cyclobutenols via an unusual Rh(I)-catalyzed intermolecular oxa-Michael addition of a tertiary alcohol with acrylonitrile, followed by an intramolecular conjugate addition/migratory insertion. Subsequent C(sp3)-C(sp3) bond cleavage through a Rh-catalyzed ß-carbon elimination is then theorized to furnish the oxepane scaffold. Computational studies support the formation of an intermediate [3.2.0] bicycle but also point to an alternative pathway for the formation of the oxepane products involving a Rh(III) intermediate. Additional studies have shown the overall process to be stereoretentive. The functional groups that are introduced in this process can be leveraged to form fused or bridged ring systems.

Stabilization of Naphthalene Diimide Anions by Ion Pair Formation in Nonaqueous Organic Redox Flow Batteries.

In redox flow batteries, a compelling strategy for enhancing the charge capacity of redox-active organic molecules involves storing multiple electrons within a single molecule. However, this approach poses unique challenges such as chemical instability by forming radicals, elevated energy requirements, and unsustainable charge concentration. Ion pairing is a possible solution to achieve charge neutrality and engineer redox potential shifts but has received limited attention. In this study, we demonstrate that Li+ can stabilize naphthalene diimide (NDI) anions dissolved in acetonitrile and significantly shift the second cathodic potential close to the first. Our findings, supported by density functional theory calculations and Fourier transform infrared spectroscopy, indicate that dimeric NDI species form stable ion pairs with Li+. Conversely, K+ ions exhibit weak interactions, and cyclic voltammograms confirm significant potential shifts when stronger Lewis acids and solvents with lower donor numbers are employed. Galvanostatic examinations reveal a single voltage plateau with Li+, which indicates a rapid redox process involving doubly charged NDI2- with Li+. These aggregated ion pairs offer the additional benefits of hindering crossover events, contributing to excellent cyclability, and suppressing undesirable side reactions even after 1000 redox cycles.

Spin-state crossover in photo-catalyzed nitrile dihydroboration via Mn-thiolate cooperation.

The role of S-donors in ligand-assisted catalysis using first-row metals has not been broadly investigated. Herein is described a combined experimental and computational mechanistic study of the dihydroboration of nitriles with pinacolborane (HBpin) catalyzed by the Mn(i) complex, Mn(κ3-SMeNS)(CO)3, that features thioether, imine, and thiolate donors. Mechanistic studies revealed that catalysis requires the presence of UV light to enter and remain in the catalytic cycle and evidence is presented for loss of two CO ligands. Stoichiometric reactions showed that HBpin reduces the imine N[double bond, length as m-dash]C of the ligand backbone in the absence of nitrile, forming an inactive off-cycle by-product. DFT calculations showed that the bifunctional thiolate donor, coordinative flexibility of the SMeNS ligand, and access to an open-shell intermediate are all crucuial to accessing low-energy intermediates during catalysis.

The Protective Effect of Zebularine, an Inhibitor of DNA Methyltransferase, on Renal Tubulointerstitial Inflammation and Fibrosis.

Renal fibrosis, the final pathway of chronic kidney disease, is caused by genetic and epigenetic mechanisms. Although DNA methylation has drawn attention as a developing mechanism of renal fibrosis, its contribution to renal fibrosis has not been clarified. To address this issue, the effect of zebularine, a DNA methyltransferase inhibitor, on renal inflammation and fibrosis in the murine unilateral ureteral obstruction (UUO) model was analyzed. Zebularine significantly attenuated renal tubulointerstitial fibrosis and inflammation. Zebularine decreased trichrome, α-smooth muscle actin, collagen IV, and transforming growth factor-ß1 staining by 56.2%. 21.3%, 30.3%, and 29.9%, respectively, at 3 days, and by 54.6%, 41.9%, 45.9%, and 61.7%, respectively, at 7 days after UUO. Zebularine downregulated mRNA expression levels of matrix metalloproteinase (MMP)-2, MMP-9, fibronectin, and Snail1 by 48.6%. 71.4%, 31.8%, and 42.4%, respectively, at 7 days after UUO. Zebularine also suppressed the activation of nuclear factor-κB (NF-κB) and the expression of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-1ß, and IL-6, by 69.8%, 74.9%, and 69.6%, respectively, in obstructed kidneys. Furthermore, inhibiting DNA methyltransferase buttressed the nuclear expression of nuclear factor (erythroid-derived 2)-like factor 2, which upregulated downstream effectors such as catalase (1.838-fold increase at 7 days, p < 0.01), superoxide dismutase 1 (1.494-fold increase at 7 days, p < 0.05), and NAD(P)H: quinone oxidoreduate-1 (1.376-fold increase at 7 days, p < 0.05) in obstructed kidneys. Collectively, these findings suggest that inhibiting DNA methylation restores the disrupted balance between pro-inflammatory and anti-inflammatory pathways to alleviate renal inflammation and fibrosis. Therefore, these results highlight the possibility of DNA methyltransferases as therapeutic targets for treating renal inflammation and fibrosis.

Allene C(sp2)-H Activation and Alkenylation Catalyzed by Palladium.

The selective transition-metal-mediated activation of C(sp2)-H bonds of allenes is a formidable challenge because of the competitive, intrinsic reactivity of cumulated double bonds. Herein, we report a Pd-catalyzed C-H alkenylation of electronically unbiased allenes, affording penta-1,2,4-triene products in up to 94% yield. A picolinamide directing group enables the formation of putative allenyl-palladacycles, which subsequently participate in a turnover-limiting Heck-type reaction with electron-deficient alkene coupling partners. This mechanistic proposal is consistent with experimental and computational investigations. Additionally, we report for the first time the use of picolinamide N,O-acetals as readily removable auxiliaries for C-H activation reactions, allowing the efficient alkenylation of allenyl carbinol derivatives. Successful removal of the directing groups without affecting the reactive penta-1,2,4-triene substructure of the products is demonstrated.

Fabry disease exacerbates renal interstitial fibrosis after unilateral ureteral obstruction via impaired autophagy and enhanced apoptosis.

BACKGROUND: Fabry disease is a rare X-linked genetic lysosomal disorder caused by mutations in the GLA gene encoding alpha-galactosidase A. Despite some data showing that profibrotic and proinflammatory cytokines and oxidative stress could be involved in Fabry disease-related renal injury, the pathogenic link between metabolic derangement within cells and renal injury remains unclear. METHODS: Renal fibrosis was triggered by unilateral ureteral obstruction (UUO) in mice with Fabry disease to investigate the pathogenic mechanism leading to fibrosis in diseased kidneys. RESULTS: Compared to kidneys of wild-type mice, lamellar inclusion bodies were recognized in proximal tubules of mice with Fabry disease. Sirius red and trichrome staining revealed significantly increased fibrosis in all UUO kidneys, though it was more prominent in obstructed Fabry kidneys. Renal messenger RNA levels of inflammatory cytokines and profibrotic factors were increased in all UUO kidneys compared to sham-operated kidneys but were not significantly different between UUO control and UUO Fabry mice. Protein levels of Nox2, Nox4, NQO1, catalase, SOD1, SOD2, and Nrf2 were not significantly different between UUO control and UUO Fabry kidneys, while the protein contents of LC3-II and LC3-I and expression of Beclin1 were significantly decreased in UUO kidneys of Fabry disease mouse models compared with wild-type mice. Notably, TUNEL-positive cells were elevated in obstructed kidneys of Fabry disease mice compared to wild-type control and UUO mice. CONCLUSION: These findings suggest that impaired autophagy and enhanced apoptosis are probable mechanisms involved in enhanced renal fibrosis under the stimulus of UUO in Fabry disease.

4-Methoxyphenyl (E)-3-(Furan-3-yl) Acrylate Inhibits Vascular Smooth Muscle Cell Proliferation.

The Cordyceps extract exhibits antiproliferative potential in vascular smooth muscle cells (SMCs) through the mitogen-activated protein kinase signaling pathway. In this study, we aimed to identify the active compounds in the Cordyceps extract and analyze their role in remodeling the arterial wall. On investigation, we discovered the following active compound: 4-methoxyphenyl (E)-3-(furan-3-yl) acrylate and synthesized it. We performed antiproliferation and antimigration assays in addition to an in vivo vessel wall remodeling experiment. Investigation of the mechanism adopted by the active compound to remodel the vessel was performed. The newly synthesized compound inhibited the proliferation and migration of SMCs. Treatment with the synthesized compound reduced neointima formation in the balloon-injured Sprague-Dawley rat model. In addition, this compound inhibited the activation of matrix metalloproteinase-2 and matrix metalloproteinase-9 in type I collagen-activated SMCs. Moreover, this compound suppressed the expression of cycloxygenase-2 (COX-2) in SMCs. Therefore, this compound can exert potential antiarteriosclerotic effects by modulating vessel wall remodeling. In conclusion, the newly synthesized 4-methoxyphenyl (E)-3-(furan-3-yl) acrylate might be an alternative therapeutic intervention for the treatment of atherosclerosis.

C-H/C-C Functionalization Approach to N-Fused Heterocycles from Saturated Azacycles.

Herein we report the synthesis of substituted indolizidines and related N-fused bicycles from simple saturated cyclic amines through sequential C-H and C-C bond functionalizations. Inspired by the Norrish-Yang Type II reaction, C-H functionalization of azacycles is achieved by forming α-hydroxy-ß-lactams from precursor α-ketoamide derivatives under mild, visible light conditions. Selective cleavage of the distal C(sp2)-C(sp3) bond in α-hydroxy-ß-lactams using a Rh-complex leads to α-acyl intermediates which undergo sequential Rh-catalyzed decarbonylation, 1,4-addition to an electrophile, and aldol cyclization, to afford N-fused bicycles including indolizidines. Computational studies provide mechanistic insight into the observed positional selectivity of C-C cleavage, which depends strongly on the groups bound to Rh trans to the phosphine ligand.

Empagliflozin Contributes to Polyuria via Regulation of Sodium Transporters and Water Channels in Diabetic Rat Kidneys.

Besides lowering glucose, empagliflozin, a selective sodium-glucose cotransporter-2 (SGLT2) inhibitor, have been known to provide cardiovascular and renal protection due to effects on diuresis and natriuresis. However, the natriuretic effect of SGLT2 inhibitors has been reported to be transient, and long-term data related to diuretic change are sparse. This study was performed to assess the renal effects of a 12-week treatment with empagliflozin (3 mg/kg) in diabetic OLETF rats by comparing it with other antihyperglycemic agents including lixisenatide (10 µg/kg), a glucagon-like peptide receptor-1 agonist, and voglibose (0.6 mg/kg), an α-glucosidase inhibitor. At 12 weeks of treatment, empagliflozin-treated diabetic rats produced still high urine volume and glycosuria, and showed significantly higher electrolyte-free water clearance than lixisenatide or voglibose-treated diabetic rats without significant change of serum sodium level and fractional excretion of sodium. In empagliflozin-treated rats, renal expression of Na+-Cl- cotransporter was unaltered, and expressions of Na+/H+ exchanger isoform 3, Na+-K+-2Cl- cotransporter, and epithelial Na+ channel were decreased compared with control diabetic rats. Empagliflozin increased an expression of aquaporin (AQP)7 but did not affect AQP3 and AQP1 protein expressions in diabetic kidneys. Despite the increased expression in vasopressin V2 receptor, protein and mRNA levels of AQP2 in empagliflozin-treated diabetic kidneys were significantly decreased compared to control diabetic kidneys. In addition, empagliflozin resulted in the increased phosphorylation of AQP2 at S261 through the increased cyclin-dependent kinases 1 and 5 and protein phosphatase 2B. These results suggest that empagliflozin may contribute in part to polyuria via its regulation of sodium channels and AQP2 in diabetic kidneys.

Inhibition of p300/CBP-Associated Factor Attenuates Renal Tubulointerstitial Fibrosis through Modulation of NF-kB and Nrf2.

p300/CBP-associated factor (PCAF), a histone acetyltransferase, is involved in many cellular processes such as differentiation, proliferation, apoptosis, and reaction to cell damage by modulating the activities of several genes and proteins through the acetylation of either the histones or transcription factors. Here, we examined a pathogenic role of PCAF and its potential as a novel therapeutic target in the progression of renal tubulointerstitial fibrosis induced by non-diabetic unilateral ureteral obstruction (UUO) in male C57BL/6 mice. Administration of garcinol, a PCAF inhibitor, reversed a UUO-induced increase in the renal expression of total PCAF and histone 3 lysine 9 acetylation and reduced positive areas of trichrome and α-smooth muscle actin and collagen content. Treatment with garcinol also decreased mRNA levels of transforming growth factor-ß, matrix metalloproteinase (MMP)-2, MMP-9, and fibronectin. Furthermore, garcinol suppressed nuclear factor-κB (NF-κB) and pro-inflammatory cytokines such as tumor necrosis factor-α and IL-6, whereas it preserved the nuclear expression of nuclear factor erythroid-derived 2-like factor 2 (Nrf2) and levels of Nrf2-dependent antioxidants including heme oxygense-1, catalase, superoxide dismutase 1, and NAD(P)H:quinone oxidoreductase 1. These results suggest that the inhibition of inordinately enhanced PCAF could mitigate renal fibrosis by redressing aberrant balance between inflammatory signaling and antioxidant response through the modulation of NF-κB and Nrf2.

Dielectric imaging for differentiation between cancer and inflammation in vivo.

In this study, we develop an in vivo dielectric imaging technique that measures capacitance using pin-type electrode arrays. Compared to normal tissues, cancer tissues exhibit higher capacitance values, allowing us to image the cancer region and monitor the chemotherapeutic effects of cancer in real-time. A comparison with the histopathological results shows that the in vivo dielectric imaging technique is able to detect small tumors (<3 mm) and tumor-associated changes. In addition, we demonstrate that cancer and inflammation may be distinguished by measuring the capacitance images at different frequencies. In contrast, the positron emission tomography using 2-[18F]-fluoro-2-deoxy-D-glucose was not capable of discriminating between cancer and inflammation.

Angiogenic characteristics of human stromal vascular fraction in ischemic hindlimb.

INTRODUCTION: In this study, we sought to characterize the angio-vasculogenic property of human adipose tissue-derived stromal vascular fraction (SVF) and to determine the therapeutic potential of SVF in the context of experimental ischemia. Although human SVF is used for cell therapy, its angiogenic and vasculogenic characteristics have not been fully elucidated. METHODS AND RESULTS: We conducted flow cytometry, microarray, quantitative (q)-PCR, Matrigel tube formation assays and in vivo therapeutic assays using an ischemic hind limb mouse model. Gene/micro RNA microarray, quantitative (q)-PCR results revealed that the representative pro-angiogenic factors were highly upregulated in SVF compared with human adipose-derived mesenchymal stem cells (ASCs). In addition, SVF exhibited high expression of endothelium-specific genes and showed robust in vitro micro-vascular formation. SVF was transplanted into ischemic mouse hind limbs and compared with ASC transplantation. SVF transplantation prevented limb loss and augmented blood perfusion, indicating that SVF promotes neovascularization in hind limb ischemia. Transplanted SVF showed high vasculogenic potential in vivo compared with transplanted ASCs. CONCLUSIONS: Our data indicate that SVF has remarkable therapeutic effects on hind limb ischemia via robust angiogenic and vasculogenic activity.

Stromal vascular fraction shows robust wound healing through high chemotactic and epithelialization property.

BACKGROUND: Although human stromal vascular fraction (SVF) has been regarded as an attractive stem cell source, its therapeutic mechanism in wound healing has not been fully elucidated. AIMS: In this study, we investigated the molecular characteristics and therapeutic property of SVF for wound healing. METHODS: Microarray data showed that SVF cells are enriched with a higher level of wound healing or epithelium development-related genes and micro RNA. RESULTS: Quantitative polymerase chain reaction (PCR) and reverse transcriptase PCR results revealed that the epithelialization growth factor, epidermal growth factor (EGF), chemokines, stromal cell-derived factor (SDF-1 or CXCL12), neutrophil-activating protein-2 (NAP-2 or CXCL7), chemokine receptors (CXCR1, CCR2 and CCR3) and wound healing genes were up-regulated in SVF compared with those in adipose-derived mesenchymal stem cells (ASCs). An in vitro scratch wound closure experiment demonstrated that co-culture with SVF substantially accelerated the wound closure of fibroblasts. Wounds in nude mice were created by skin excisions followed by injections of SVF with Pluronic hydrogel. SVF implantation highly accelerated wound closure and increased cellularity and re-epithelialization. In addition, the transplanted SVF exhibited high engraftment rates in the wound area, suggesting direct benefits for cutaneous closure. CONCLUSIONS: Taken together, these data suggest that SVF possesses high therapeutic capability for wound healing via the secretion of epithelialization and chemotactic growth factors and enhanced engraftment properties.

Erratum: In Vitro Evaluation of Allergen Potencies of Commercial House Dust Mite Sublingual Immunotherapy Reagents.

This corrects the article on p. 124 in vol. 7, PMID: 25729619.

Cross-Reactivity between Oak and Birch Pollens in Korean Tree Pollinosis.

Oak and birch trees belong to Fagales order. Specific IgE to pollen allergens of both trees are frequently found in Korea pollinosis patients. Oak trees which comprise 40% of forest area are common in Korea. However, birch trees are sparse. We compared the allergenicity of pollen extracts of white oak, sawtooth and Mongolian oaks which are prevalent species in Korea, with the pollen extract of birch. The cross-reactivity of four pollen extracts was examined with pooled sera of 12 patients by ELISA, immunoblotting and CAP inhibitions. A protein of 17 kDa, putatively homologous to a major birch allergen Bet v 1, displayed strong IgE reactivity from white oak and sawtooth oak pollen extract but not from Mongolian oak pollen. Notably, a 23-kDa protein from sawtooth and white oaks showed strong IgE reactivity and inhibited by Bet v 1. IgE binding to white oak was inhibited a maximum of 94.6% by white oak, 93.4% by sawtooth oak, 83.2% by Mongolian oak, and 68.8% by birch. Furthermore, sawtooth oak, white oak, and Mongolian oak extracts were able to inhibit up to 78.5%, 76.6% and 67.3% of IgE binding to birch extract, while birch extract itself inhibited up to 94.3%. Specific IgE to Bet v 1 was inhibited a maximum of 79.1% by sawtooth oak, 77.4% by white oak, and 72.7% by Mongolian oak, while 81.5% inhibition was shown by birch. Bet v 1 was able to partially inhibit its homologous molecules from sawtooth oak and white oak in immunoblotting. Birch pollen extract was found to be cross-reactive primarily with Bet v 1-homologous allergen from oak pollens in Korea pollinosis patients. Considering the sparseness of birch tree in Korea, oak, especially sawtooth oak may be the main cause of tree pollinosis in Korea, rather than birch.

IgE Reactivity of Recombinant Pac c 3 from the Asian Needle Ant (Pachycondyla chinensis).

BACKGROUND: Stings from the Asian needle ant are an important cause of anaphylaxis in East Asia. A 23-kDa protein homologous to antigen 5 is the major allergen produced by these ants. In this study, we aimed to produce a recombinant antigen 5 allergen, Pac c 3. METHODS: Recombinant Pac c 3 allergen from the Asian needle ant was expressed in Pichia pastoris and purified by ammonium sulfate precipitation and Ni affinity chromatography. IgE reactivity was demonstrated by ELISA and immunoblotting. RESULTS: The recombinant protein was recognized in 5 of 6 (83.3%) serum samples from patients with demonstrated anaphylaxis to ants. IgE reactivity to an antigen 5 allergen from Asian needle ant venom sac extract was specifically inhibited by the recombinant protein. It was also able to inhibit IgE binding to the vespid allergen Ves v 5 by ImmunoCAP analysis, indicating the presence of cross-reactivity. CONCLUSION: A recombinant Pac c 3, cross-reactive with Ves v 5, from the Asian needle ant was successfully produced in the methylotrophic yeast P. pastoris. This protein could be useful for the development of component-resolved diagnostics.

Standardization of Weed Pollen Extracts, Japanese Hop and Mugwort, in Korea.

PURPOSE: Japanese hop (Humulus spp.) and mugwort (Artemisia spp.) are notable causes of autumn pollinosis in East Asia. However, Japanese hop and mugwort pollen extracts, which are widely used for the diagnosis, have not been standardized. This study was performed to standardize Japanese hop and mugwort pollen extracts. MATERIALS AND METHODS: Allergen extracts were prepared in a standardized way using locally collected Humulus japonicus and purchased Artemisia vulgaris pollens. The immunoglobulin E (IgE) reactivities of prepared extracts were compared with commercial extracts via IgE immunoblotting and inhibition analyses. Intradermal skin tests were performed to determine the bioequivalent allergy unit (BAU). RESULTS: The IgE reactive components of the extracts via IgE immunoblotting were similar to those of commercial extracts. A 11-kDa allergen showed the strongest IgE reactivity in Japanese hop, as did a 28-kDa allergen in mugwort pollen extracts. Allergenic potencies of the investigatory Japanese hop and mugwort extracts were essentially indistinguishable from the commercial ones. Sums of erythema of 50 mm by the intradermal skin test (ΣED50) were calculated to be 14.4th and 13.6th three-fold dilutions for Japanese hop and mugwort extracts, respectively. Therefore, the allergenic activity of the prepared extracts was 90827.4 BAU/mg for Japanese hop and 34412 BAU/mg for mugwort. CONCLUSION: We produced Japanese hop and mugwort pollen extracts using a standardized method. Standardized Japanese hop and mugwort pollen extracts will facilitate the production of improved diagnostic and immunotherapeutic reagents.

Allergenic Characterization of 27-kDa Glycoprotein, a Novel Heat Stable Allergen, from the Pupa of Silkworm, Bombyx mori.

Boiled silkworm pupa is a traditional food in Asia, and patients with silkworm pupa food allergy are common in these regions. Still now only one allergen from silkworm, arginine kinase, has been identified. The purpose of this study was to identify novel food allergens in silkworm pupa by analyzing a protein extract after heat treatment. Heat treated extracts were examined by proteomic analysis. A 27-kDa glycoprotein was identified, expressed in Escherichia coli, and purified. IgE reactivity of the recombinant protein was investigated by ELISA. High molecular weight proteins (above 100 kDa) elicited increased IgE binding after heat treatment compared to that before heat treatment. The molecular identities of these proteins, however, could not be determined. IgE reactivity toward a 27-kDa glycoprotein was also increased after heating the protein extract. The recombinant protein was recognized by IgE antibodies from allergic subjects (33.3%). Glycation or aggregation of protein by heating may create new IgE binding epitopes. Heat stable allergens are shown to be important in silkworm allergy. Sensitization to the 27-kDa glycoprotein from silkworm may contribute to elevation of IgE to silkworm.

Cordyceps bassiana inhibits smooth muscle cell proliferation via the ERK1/2 MAPK signaling pathway.

Cordyceps belongs to a genus of acormycete fungi and is known to exhibit various pharmacological effects. The aim of this study was to investigate the effect of Cordyceps species on the proliferation of vascular smooth muscle cells (VSMC) and their underlying molecular mechanism. A cell proliferation assay showed that Cordyceps bassiana ethanol extract (CBEE) significantly inhibited VSMC proliferation. In addition, neointimal formation was significantly reduced by treatment with CBEE in the carotid artery of balloon-injured rats. We also investigated the effects of CBEE on the extracellular signal-regulated kinase (ERK) signal pathway. Western blot analysis revealed increased ERK 1/2 phosphorylation in VSMCs treated with CBEE. Pretreatment with U0126 completely abrogated CBEE-induced ERK 1/2 phosphorylation. In conclusion, CBEE exhibited anti-proliferative properties that affected VSMCs through the ERK1/2 MAPK signaling pathway. Our data may elucidate the inhibitory mechanism of this natural product.

In vitro evaluation of allergen potencies of commercial house dust mite sublingual immunotherapy reagents.

PURPOSE: The clinical efficacy of allergen-immunotherapy is known to be dose dependent. However, optimal maintenance dosage has not yet been determined for sublingual immunotherapy (SLIT). Furthermore, since companies adopt their own units for expression of allergenicity, the allergen concentrations of individual reagents cannot be compared easily. We sought to measure and compare the allergenicities of 3 commercially available house dust mite (HDM) SLIT regents and a subcutaneous immunotherapy reagent. METHODS: We measured the HDM allergenic potency of the maintenance dosages of three SLIT reagents: Staloral® (300 index of reactivity [IR] /mL, recommended maintenance dosage [MD]: 120 IR), SLITone® (1,000 standard therapeutic unit [STU]/mL, recommended MD: 200 STU), Wolwopharma® (100 µg/mL, recommended MD: 20 µg), and subcutaneous immunotherapy regents of Hollister-Stier (10,000 allergy unit [AU] /mL). The allergenic potency was assessed by measuring the total protein concentrations, mite group 1 and 2 allergens using 2-site ELISA, and an inhibition test against IgE specific to Dermatophagoides farinae and Dermatophagoides pteronyssinus. RESULTS: The protein content of the Wolwopharma® reagent was 1.5-261.4 times higher than that of the other 2 SLIT reagents. The concentration of group 1 major allergens in Staloral® (132.03 µg/mL) was 33- to 44.5-fold higher than in SLITone® (4.00 µg/mL) and Wolwopharma® (2.97 µg/mL). The concentration of group 2 major allergen was also 8.9- to 10.5-fold higher in Staloral® (15.7 µg/mL) than in SLITone® (1.8 µg/mL) or Wolwopharma® (1.5 µg/mL). An ELISA inhibition study against HDM-specific IgE showed that the allergen potency of Staloral® reagent is 8.5-fold and 21-fold higher than that of SLITone® or Wolwopharma®, respectively. The differences between the maintenance dosages are further exaggerated by the differences in the recommended volumes of SLIT reagents. CONCLUSIONS: The allergen potencies of commercially available HDM SLIT reagents are markedly different. Consensus regarding the optimal allergen concentration for SLIT reagents used to treat HDM respiratory allergies is needed.