Treatment strategy after noncurative endoscopic resection for early gastric cancers in patients aged ≥ 85 years: a multicenter retrospective study in a highly aged area of Japan.

BACKGROUND: The guidelines recommend additional gastrectomy after noncurative endoscopic resection for early gastric cancers (EGCs). However, no additional treatment might be acceptable in some patients aged ≥ 85 years. We aimed to identify this patient group using the data in a highly aged area. METHODS: We enrolled patients aged ≥ 85 years after noncurative endoscopic resection for EGCs at 30 institutions of the Tohoku district in Japan between 2002 and 2017. Treatment selection and prognosis after noncurative endoscopic resection were investigated. Fourteen candidates were evaluated using the Cox model to identify risk factors for poor overall survival (OS) in patients with no additional treatment. RESULTS: Of 1065 patients aged ≥ 85 years, 143 underwent noncurative endoscopic resection. Despite the guidelines' recommendation, 88.8% of them underwent no additional treatment. The 5-year OS rates in those with additional gastrectomy and those with no additional treatment were 63.1 and 65.2%, respectively. Multivariate analysis showed independent risk factors for poor OS in patients with no additional treatment were the high-risk category in the eCura system (hazard ratio [HR], 2.91), Charlson comorbidity index (CCI) ≥ 3 (HR, 2.78), and male (HR, 2.04). In patients with no additional treatment, nongastric cancer-specific survival was low (69.0% in 5 years), whereas disease-specific survival rates were very high in the low- and intermediate-risk categories of the eCura system (100.0 and 97.1%, respectively, in 5 years). CONCLUSIONS: No additional treatment may be acceptable in the low- and intermediate-risk categories of the eCura system in patients aged ≥ 85 years with noncurative endoscopic resection for EGCs.

Prognostic Benefit of Additional Treatment After Endoscopic Submucosal Dissection for Esophageal Squamous Cell Carcinoma.

BACKGROUND: Although additional treatment is considered for patients with esophageal squamous cell carcinoma (ESCC) invading into the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic submucosal dissection (ESD), the actual benefits of this method remain to be elucidated. AIMS: We aimed to evaluate the prognostic benefits of additional treatment in such patients. METHODS: Between 2006 and 2017, we enrolled patients with pT1a-MM/pT1b-SM ESCC after ESD at 21 institutions in Japan. Overall survival (OS) and disease-specific survival (DSS) were compared between the additional treatment and follow-up groups after propensity score matching, to reduce the bias of baseline characteristics. A subgroup analysis was performed according to the pathological findings: category A, pT1a-MM but negative for lymphovascular invasion (LVI) and vertical margin (VM); category B, tumor invasion into the submucosa ≤ 200 µm but negative for LVI and VM; category C, others. RESULTS: Of 593 patients with pT1a-MM/pT1b-SM ESCC after ESD, 101 matched pairs were extracted after propensity score matching. The OSs were similar between the additional treatment and follow-up groups (80.6% vs. 78.6% in 5 years; P = 0.972). In a subgroup analysis, the OS in the additional treatment group was significantly lower than that in the follow-up group (65.7% vs. 95.2% in 5 years; P = 0.037) in category A, whereas OS did not significantly differ in category C (76.8% vs. 69.5% in 5 years; P = 0.360). CONCLUSIONS: Additional treatment after ESD in patients with pT1a-MM/pT1b-SM ESCC was not associated with an improved prognosis.

Prediction model of 3-year survival after endoscopic submucosal dissection for early gastric cancer in elderly patients aged ≥ 85 years: EGC-2 model.

PURPOSE: Little is known about the prognostic factors for survival after endoscopic submucosal dissection (ESD) in elderly patients with early gastric cancer (EGC). The aim of this study is to determine prognostic factors and a prediction model of 3-year survival after ESD for EGC in patients aged ≥ 85 years. METHODS: We retrospectively evaluated the clinical outcomes of 740 patients with EGC aged ≥ 85 years, who were treated by ESD at 30 institutions in Japan. Overall survival (OS) and disease-specific survival (DSS) were calculated with the Kaplan-Meier method. Prediction models for 3-year OS after ESD were estimated using the Cox proportional hazards model based on Uno's C-statistics. RESULTS: During the follow-up period, 309 patients died of any cause and 10 patients died of gastric cancer. OS and DSS after 3 years were 82.7% and 99.2%, respectively. No significant differences in OS were found among curability categories. The Cox proportional hazards model revealed the geriatric nutritional risk index (GNRI) and the Charlson comorbidity index (CCI) to be predictors of 3-year survival. We established a final model (EGC-2 model) expressed by GNRI - (2.2×CCI) with a cutoff value of 96. The overall survival rate was significantly lower in the model value < 96 group than in the model value ≥ 96 group (P < 0.001). CONCLUSIONS: The prediction model using GNRI and CCI will be useful to support decision-making for the treatment of EGC in elderly patients aged ≥ 85 years.

Combined assessment of clinical and pathological prognostic factors for deciding treatment strategies for esophageal squamous cell carcinoma invading into the muscularis mucosa or submucosa after endoscopic submucosal dissection.

OBJECTIVES: We aimed to clarify the prognostic factors for patients with esophageal squamous cell carcinoma (ESCC) invading into the muscularis mucosa (pT1a-MM) or submucosa (pT1b-SM) after endoscopic submucosal dissection (ESD). METHODS: This retrospective study enrolled such patients at 21 institutions in Japan between 2006 and 2017. We evaluated 15 factors, including pathological risk categories for ESCC-specific mortality, six non-cancer-related indices, and treatment strategies. RESULTS: In the analysis of 593 patients, the 5-year overall and disease-specific survival rates were 83.0% and 97.6%, respectively. In a multivariate Cox analysis, male sex (hazard ratio [HR] 3.56), Charlson comorbidity index (CCI) ≥3 (HR 2.53), ages of 75-79 (HR 1.61) and ≥80 years (HR 2.04), prognostic nutrition index (PNI) <45 (HR 1.69), and pathological intermediate-risk (HR 1.63) and high-risk (HR 1.89) were prognostic factors. Subsequently, we developed a clinical risk classification for non-ESCC-related mortality based on the number of prognostic factors (age ≥75 years, male sex, CCI ≥3, PNI <45): low-risk, 0; intermediate-risk, 1-2; and high-risk, 3-4. The 5-year non-ESCC-related mortality rates for patients without additional treatment were 0.0%, 10.2%, and 45.8% in the low-, intermediate-, and high-risk groups, respectively. Meanwhile, the 5-year ESCC-specific mortality rates for the pathological low-, intermediate-, and high-risk groups were 0.3%, 5.3%, and 18.2%, respectively. CONCLUSIONS: We clarified prognostic factors for patients with pT1a-MM/pT1b-SM ESCC after ESD. The combined assessment of non-ESCC- and ESCC-related mortalities by the two risk classifications might help clinicians in deciding treatment strategies for such patients.

Risk of metastatic recurrence after endoscopic resection for esophageal squamous cell carcinoma invading into the muscularis mucosa or submucosa: a multicenter retrospective study.

BACKGROUND: We aimed to elucidate the risk of metastatic recurrence after endoscopic resection (ER) without additional treatment for esophageal squamous cell carcinomas (ESCCs) with tumor invasion into the muscularis mucosa (pT1a-MM) or submucosa (T1b-SM). METHODS: We retrospectively enrolled patients with pT1a-MM/pT1b-SM ESCC after ER at 21 institutions in Japan between 2006 and 2017. We compared metastatic recurrence between patients with and without additional treatment, stratified into category A (pT1a-MM with negative lymphovascular invasion [LVI] and vertical margin [VM]), B (tumor invasion into the submucosa ≤ 200 µm [pT1b-SM1] with negative LVI and VM), and C (others). Subsequently, using multivariate Cox analysis, we evaluated risk factors for metastatic recurrence after ER without additional treatment. RESULTS: We enrolled 593 patients, and metastatic recurrence occurred in 38 patients. Metastatic recurrence after additional treatment was significantly lower than that after no additional treatment in category C (9.1% vs. 23.6% in 5 years, p = 0.001), whereas no significant difference was noted in categories A (0.0% vs. 2.6%) and B (0.0% vs. 4.3%). In patients without additional treatment after ER, risk factors for metastatic recurrence were lymphatic invasion (hazard ratio [HR], 5.61), positive VM (HR, 4.55), and tumor invasion into the submucosa > 200 µm (HR, 3.25), and, but near half of the patients with metastatic recurrence had no further recurrence after salvage treatment, resulting in excellent 5-year disease-specific survival in categories A (99.6%) and B (100.0%). CONCLUSIONS: Closed follow-up with no additional treatment may be an acceptable option after ER in pT1a-MM/pT1b-SM1 ESCC with negative LVI and VM.

Vimentin-positive gastric adenocarcinoma arising in a hyperplastic polyp.

We report a case of vimentin-positive early gastric adenocarcinoma arising in a hyperplastic polyp (HP). A 72-year-old Japanese man was admitted for the detailed examination of a gastric polyp. He had a subtotal gastrectomy due to acute abdomen 12 years ago. Upper endoscopy revealed a pedunculated polyp measuring approximately 2 cm on the greater curvature of upper body of the remnant stomach. Magnifying endoscopy revealed that the microsurface pattern was irregular and partially absent accompanied with irregular microvessels at the upper end of the polyp. We speculated that the lesion was an adenocarcinoma arising in the HP. Endoscopic submucosal dissection (ESD) was performed. Histological examination of the ESD specimen revealed that the lesion consisted of well- to poorly differentiated adenocarcinoma at the protruding lesion and foveolar hyperplastic epithelia at the base of the polyp. Immunohistochemically, most of tumor cells that comprised poorly-differentiated adenocarcinoma were positive for both cytokeratin and vimentin. Although carcinomas have occasionally been found in HPs, the histological features of the present case are considered extremely unusual. To the best of our knowledge, this is the first case of vimentin-positive early gastric carcinoma arising in a HP.

Radiosensitization by Liposome-Encapsulated Fullerenes to Mitochondria/DNA-Damages on Human Melanoma Cells.

The polyhydroxy small-gap fullerenes [C120O30(OH)30 · 30H2O · 25Na+: SGFs] were encapsulated in multilamellar liposomes (Lpsm) composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS), which are designated as LpsmSGFs (DOPC/DOPS/SGFs = 35 mM:15 mM:246-445 µM, diameter = 141.2 nm, ζ-potential = -35.65 mV). Radiosensitization by LpsmSGFs under X-ray irradiation was evaluated on human melanoma HMV-II cells. On 7th day after X-ray irradiation, cell proliferation degree assessed by WST-8 decreased more markedly on cells pretreated with LpsmSGFs than Lpsm or free-SGFs. Fluorescent imaging of cells with Rhodamine123, dihydroethidium or anti-8-hydroxydeoxyguanosine antibody was monitored as an indicator for mitochondrial membrane potentials, intracellular superoxide anion radicals (O˙-2) or oxidative DNA-damages, respectively. After X-ray irradiation, LpsmSGFs obviously exhibited more augmented mitochondrial membrane potentials on perinuclear region of cells than Lpsm or free-SGFs. Without X-ray irradiation, superoxide anion radicals were found principally in the cytoplasm, but, when exposed to X-ray, they were found in cell nuclei associated with oxidative DNA-damages on cells pretreated with LpsmSGFs. Meanwhile, the oxidation-reduction potentials of SGFs aqueous solution increased by X-ray irradiation. These results suggest that LpsmSGFs-mediated generation of reactive oxygen species results in damages to cellular components such as mitochondria and DNA on cells, and thereby cell proliferation decreased. The LpsmSGFs has a potential as a pro-oxidative type radiosensitizer.

Two Cases of Primary Sclerosing Cholangitis Overlapping with Autoimmune Hepatitis in Adults.

Overlap syndrome between primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) is extremely rare in Japan. We herein report two adult patients with PSC-AIH overlap syndrome. They were diagnosed with PSC-AIH overlap syndrome based on the findings of endoscopic retrograde cholangiography and liver biopsy, and using the International Autoimmune Hepatitis Group scoring system. In both cases, PSC preceded AIH, and combination therapy with steroid and ursodeoxycholic acid was effective. Because there are few reported cases in Japan, it is important to study more cases to shed light on the clinical and pathological features of PSC-AIH overlap syndrome.

Incorporation of adenylate cyclase into membranes of giant liposomes using membrane fusion with recombinant baculovirus-budded virus particles.

Recombinant transmembrane adenylate cyclase (AC) was incorporated into membranes of giant liposomes using membrane fusion between liposomes and baculovirus-budded virus (BV). AC genes were constructed into transfer vectors in a form fused with fluorescent protein or polyhistidine at the C-terminus. The recombinant BVs were collected by ultracentrifugation and AC expression was verified using western blotting. The BVs and giant liposomes generated using gentle hydration were fused under acidic conditions; the incorporation of AC into giant liposomes was demonstrated by confocal laser scanning microscopy through the emission of fluorescence from their membranes. The AC-expressing BVs were also fused with liposomes containing the substrate (ATP) with/without a specific inhibitor (SQ 22536). An enzyme immunoassay on extracts of the sample demonstrated that cAMP was produced inside the liposomes. This procedure facilitates direct introduction of large transmembrane proteins into artificial membranes without solubilization.

Multiple gastric G1 neuroendocrine tumors with venous and lymphatic invasion.

A 60-year-old woman was admitted for the treatment of a gastric neuroendocrine tumor (NET) associated with type A chronic atrophic gastritis. The lesion measured 10 mm in diameter, and a computed tomography scan did not reveal any metastatic lesions. Endoscopic submucosal dissection (ESD) was subsequently performed. A histological examination revealed three gastric NETs, two of which exhibited vessel invasion. Endocrine cell micronests associated with a high risk of recurrence were also observed. Therefore, the patient underwent total gastrectomy with lymph node dissection. Because vessel invasion can occur in patients with small gastric NET G1, the use of ESD should be considered to carefully estimate the presence of invasion.

Aortoesophageal fistula after thoracic endovascular aortic repair diagnosed and followed with endoscopy.

A 70-year-old man reported dysphagia two months after undergoing thoracic endovascular aortic repair (TEVAR). An endoscopic examination revealed a fistula between the esophagus and the thoracic aortic aneurysm, and computed tomography (CT) showed that the thoracic aortic aneurysm had increased in size. The patient was diagnosed with an aortoesophageal fistula (AEF), and surgical replacement of the thoracic aorta was performed. AEFs are a rare but typically fatal complication after TEVAR. Physicians should consider a diagnosis of AEF and perform endoscopic examinations and CT in patients who undergo TEVAR and subsequently complain of dysphagia.

[A case of graft-duodenal fistula 25 years after operation for aortic coarctation].

A 40-year-old man who underwent extra-anatomical bypass for aortic coarctation 25 years ago was admitted to another hospital with hematemesis and melena. Esophagogastroduodenoscopy revealed no bleeding site in the stomach or the first and second portion of the duodenum. He was transferred to our hospital due to hemorrhagic shock. Angiography showed the extravasation of the contrast medium from the graft. Emergency operation was performed due to graft-duodenal fistula. In patients with previous aortic graft surgery and present gastrointestinal bleeding, graft-enteric fistula should be suspected.

Cadherin-integrated liposomes with potential application in a drug delivery system.

N-cadherin (CDH2) proteins were reconstituted with liposomes using a baculovirus expression-liposome fusion method. CDH2 budded viruses were fused with giant liposomes containing dioleoylphophogycerol/dioleoylphosphatidylcholine (DOPG/DOPC) at pH 4.5 and the localization of CDH2 on the liposome membrane was observed by confocal laser scanning microscopy. CDH2 liposomes showed Ca(2+)-dependent association. CDH2-mediated association/dissociation in CDH2 liposomes was specific to Ca(2+) and reversible. CDH2-expressing LN-229 cells (human glioblastoma cell) adhered to CDH2 liposomes and small CDH2 liposomes (diameter approximately 150 nm), in particular, were internalized by endocytosis and partly escaped endosomes. Cadherin-containing liposomes show high potential as a new cell-specific proteoliposome. The baculovirus expression-liposome fusion method is useful as a new enabling technology for biomedical applications of functional proteoliposomes.

Morphometry for microvessels in early gastric cancer by narrow band imaging-equipped magnifying endoscopy.

BACKGROUND AND AIM: Microvascular architecture is a variable characterizing early gastric cancer (EGC) against the background. The aims of the present study were to measure morphological variables of the microvessels and to compare the variables between EGC and the background. METHODS: Narrow band imaging (NBI)-equipped magnifying endoscopic pictures from 32 patients with EGC were used. The endoscopic pictures were taken under maximal magnification and processed for the microvessels in an in-focus area after correction of image distortion. The segmented microvessels were numbered for microvessel density (counts/mm(2)) and vascular bed area (% ratio of vascular bed against the region of interest). The microvessels were further processed for a set of skeletonized pixels to count the characteristic points, including end-points, crossing points, branching points and connecting points. RESULTS: Microvessels in cancer were found to have a significantly larger connected point number (20.5 ± 6.1, P = 0.0002) than those in the background (17.4 ± 3.9). Numbers of the end-points and branching points were found to be significantly larger in cancer than in the background (end-points 3.6 ± 0.7 for cancer vs 3.3 ± 0.4 for background, P = 0.0005; branching points 0.8 ± 0.4 for cancer vs 0.7 ± 0.2 for background, P = 0.0014). However, microvessel density, vascular bed area and mean diameter did not significantly differ between cancer and the background. CONCLUSION: This finding can be considered to reflect the reported observation of an irregular vascular pattern in gastric cancer. This method may provide a means for microvessel morphometry, regardless of the organ studied.

Histopathological phenotypes of early gastric cancer and its background mucosa.

Recent advances in endoscopic submucosal dissection (ESD) techniques contribute to endoscopic treatment of early gastric cancer (EGC). Recognition of chronic atrophic gastritis as the background is important for high-quality detection and diagnosis of EGC. But, relationships between EGC and atrophy of the background gastric mucosa caused by Helicobacter pylori are not well understood. The present study demonstrated histopathological phenotypes of EGC, as well as chronic atrophic gastritis as background mucosa of EGC. We evaluated mucosal heights, number of glands, and degree of intestinal metaplasia (IM) of the background gastric mucosa, using 81 cases of EGC resected by ESD. Gastric phenotype cancer cases showed IM of the background gastric mucosa less frequently, compared with intestinal phenotype cancer cases (score of IM, 1.15 vs. 1.65, P = 0.012). The average mucosal heights around EGC were lower in moderately to poorly differentiated adenocarcinoma cases than well differentiated adenocarcinoma cases (442.6 µm vs. 500.2 µm, P = 0.011). The mucosal atrophy indicated by average heights of background mucosa was low in the gastric phenotype cancer cases, compared with the intestinal phenotype cancercases (452.8 µm vs. 505.6 µm, P = 0.018). In the fundic gland area, the mucosal heights were low in the gastric phenotype cancer cases, compared with the intestinal phenotype cancer cases (413.2 µm vs. 495.5 µm, P = 0.015). Our results using EGC specimens indicated that gastric phenotype cancer and moderately to poorly differentiated adenocarcinoma had atrophic background mucosa with lower mucosal heights and less IM. The atrophic gastric mucosa with less IM is thought to play an important role in gastric carcinogenesis, especially tumoriogenesis of gastricphenotype cancer.

Applicability of a rapid stool antigen test, using monoclonal antibody to catalase, for the management of Helicobacter pylori infection.

BACKGROUND: Most monoclonal antibody-based stool antigen tests are of the "send-out" format. Rapid Testmate pylori antigen (Rapid TPAg) uses monoclonal antibody and is an "in-the-office" test. The aim of this study was to examine the usefulness of Rapid TPAg for the management of H. pylori infection. METHODS: One-hundred and two consecutive patients who received H. pylori eradication therapy underwent both urea breath test (UBT) and Rapid TPAg at 5-6 weeks after finishing the eradication therapy. Stool samples were maintained at -20, 5, 25, and 40°C and subjected to Rapid TPAg after 1-7 days. Stool samples were also tested by enzyme immunoassay (EIA) to quantify antigenicity. RESULTS: The agreement between Rapid TPAg and UBT in the evaluation of the results of H. pylori eradication treatment was 94.1%. The overall accuracy of Rapid TPAg and UBT to determine H. pylori eradication was 98.0 and 96.0%, respectively. The results of Rapid TPAg were not altered after storage of samples at -20 to 40°C for 7 days. Antigenicity quantified by EIA did not decrease significantly after 7 days. CONCLUSIONS: Rapid TPAg is a useful diagnostic test for immediate and accurate determination of the results of H. pylori eradication therapy. The antigenicity of stool sample suspensions was preserved for 7 days in the collection devices.

Preparation of connexin43-integrated giant Liposomes by a baculovirus expression-liposome fusion method.

Connexin-43 (Cx43) containing giant liposomes (GL) were prepared by a baculovirus expression-liposome fusion method. Recombinant budded viruses expressing Cx43 were prepared and then fused with GLs containing DOPG/DOPC at pH 4.5. Connexon formation on the GL membrane was observed by transmission electron microscope. Hydrophilic fluorescent dye transfers were observed through a Cx43-mediated pathway not only between Sf9 (Spodoptera frugiperda) cells with Cx43 but also from giant Cx43 liposomes to Cx43-expressing U2OS cells (human osteosarcoma cell). The functional connexin-containing liposome is expected to be useful for cellular cytosolic delivery systems. The original orientation and function of Cx43 was maintained after integration into the liposomes. The liposome fusion method will create new opportunities as a tool for analysis of channel membrane proteins.

Confocal microscopic observation of fusion between baculovirus budded virus envelopes and single giant unilamellar vesicles.

We assayed fusion events between giant unilamellar vesicles (GUVs) and budded viruses (BVs) of baculovirus (Autographa californica nucleopolyhedrovirus), the envelopes of which have been labeled with the fluorescent dye Alexa Fluor 488. This involves observing the intensity of fluorescence emitted from the lipid bilayer of single GUVs after fusion using laser scanning microscopy. Using this assay system, we found that fusion between single GUVs and BV envelopes was significantly enhanced at around pH 5.0-6.0, which suggests that: (1) envelope glycoprotein GP64-mediated membrane fusion within the endosome of insect cells was reproduced in our artificial system; (2) acidic phospholipids in GUVs are necessary for this fusion, which are in agreement with the previous results with conventional small liposomes including large unilamellar vesicles and multilamellar vesicles; and (3) the efficiency of fusion is significantly affected by membrane properties that can be modulated by adding cholesterol to GUV lipid bilayers. In addition, the microscopic observation of BV-fused single GUVs showed that a weak interaction occurred between BVs and GUVs containing dioleoylphosphatidylserine at pH 6.0-6.5, and components of BV envelopes were unevenly distributed upon fusion with GUVs containing saturated phospholipid with cholesterol. We further demonstrated that when the recombinant membrane protein, adrenergic beta(2) receptor, was expressed on recombinant BV envelopes, the protein distribution on BV-fused GUVs was also affected by their lipid contents.

Recombinant proteoliposomes prepared using baculovirus expression systems.

Proteoliposomes are useful for investigating the functions and properties of membrane proteins. We have established a novel method to prepare proteoliposomes using a baculovirus (Autographa californica nuclear polyhedrosis virus; AcNPV) gene expression system producing the recombinant membrane proteins to be reconstituted. This method consists of two key steps for production of recombinant proteoliposomes: (1) The cDNA of the recombinant membrane protein on a baculovirus vector is transfected into insect cells, and recombinant AcNPV budded viruses (BVs), which express the targeted proteins on their own envelopes, are collected, and (2) the BV envelopes are subjected to fusion with liposomes containing acidic phospholipids by activating the viral glycoprotein gp64 at low pH. In this chapter, we describe the reconstitution of the transmembrane proteins, thyroid-stimulating hormone receptor (TSHR, a member of G protein-coupled receptor family) and acetylcholine receptor alpha-subunit (AChRalpha), in various types of liposomes, including large unilamellar vesicles (LUVs), multilamellar vesicles (MLVs), and giant unilamellar vesicles (GUVs). Enzyme-linked immunosorbent assay (ELISA) shows that the reconstituted proteins (TSHR and AChRalpha) specifically bind their ligands (TSH and alpha-bungarotoxin), respectively, as well as antibodies against the recombinant proteoliposomes. In addition, TSHRs reconstituted on proteo-GUVs are successfully visualized using a confocal laser scanning microscope with fluorescence immunostain. These data suggest that recombinant proteoliposomes prepared using the novel method have the potential to be applied for reconstitution of complicated multicomponent membrane protein systems.

Diagnosis and discrimination of autoimmune Graves' disease and Hashimoto's disease using thyroid-stimulating hormone receptor-containing recombinant proteoliposomes.

Graves' disease (GD) is an autoimmune disease of the thyroid gland caused by autoantibodies against thyroid-stimulating hormone receptor (TSHR). Currently, the diagnostic test for TSHR autoantibodies is based on an indirect competitive binding assay that measures the ability of TSHR autoantibodies to inhibit the binding of thyroid-stimulating hormone (TSH) to TSHR. Here, we have developed a specific and direct diagnostic method for autoantibodies in GD that incorporates immobilized TSHR-containing recombinant proteoliposomes into an enzyme-linked immunosorbent assay (ELISA). To reduce non-specific binding of autoantibodies to recombinant proteoliposomes, we investigated the effect of polyethylene glycol (PEG)-lipid on the binding of commercially available anti-TSHR antibodies (aTSHRAb). The incorporation of PEG-lipids into liposomes decreased non-specific binding, as compared to liposomes that did not contain PEG-lipids, and the addition of blocking reagents further decreased non-specific reactivity. aTSHRAb exhibited higher reactivity towards PEG-modified TSHR recombinant proteoliposomes than PEG-modified liposomes without TSHR (bare liposomes). Importantly, serum autoantibodies from patients with GD, which is associated with hyperthyroidism, exhibited remarkably specific binding to TSHR recombinant proteoliposomes. Serum autoantibodies from patients with Hashimoto's disease (HD), which is associated with hypothyroidism, also reacted specifically with proteoliposomal TSHR. These results suggest that immobilized TSHR recombinant proteoliposomes can serve as a direct diagnostic test for GD and HD. Furthermore, given that there is no competition test currently available for detecting autoantibodies in HD, the combination of TSHR recombinant proteoliposome ELISA and indirect competitive TSHR binding assay might be an effective way to discriminate between GD and HD.