Role of immunoproteasomes and thymoproteasomes in health and disease

The proteasome is a multisubunit protease that degrades intracellular proteins into small peptides. Besides playing a pivotal role in many cellular processes indispensable for survival, it is involved in the production of peptides presented by major histocompatibility complex class I molecules. In addition to the standard proteasome shared in all eukaryotes, jawed vertebrates have two specialized forms of proteasome known as immunoproteasomes and thymoproteasomes. The immunoproteasome, which contains cytokine-inducible catalytic subunits with distinct cleavage specificities, produces peptides presented by class I molecules more efficiently than the standard proteasome. The thymoproteasome, which contains a unique catalytic subunit β5t, is a tissue-specific proteasome expressed exclusively in cortical thymic epithelial cells. It plays a critical role in CD8⁺ cytotoxic T cell development via positive selection. This review provides a brief overview on the structure and function of these specialized forms of proteasome and their involvement in human disease.     

Evaluation of bioartificial renal tubule device prepared with human renal proximal tubular epithelial cells cultured in serum-free medium

Bioartificial renal tubule devices (BTD) use cell therapy to improve conditions commonly observed in recipients of artificial kidneys for treatment of kidney diseases. We previously reported significant improvement of the condition of acute kidney injury (AKI) animals after treatment with BTD prepared with lifespan-extended human renal proximal tubular cells (hRPTEC). However, a major obstacle to use of BTD for patients is their biological safety, because hRPTEC are cultured in medium containing fetal calf serum. To establish the biological safety of BTD, we prepared BTD with lifespan-extended hRPTEC cultured in a newly developed serum-free medium and compared these with BTD prepared with hRPTEC cultured in serum-containing conventional medium. Lifespan-extended hRPTEC cultured in serum-free medium (hRPTEC-SFM) can proliferate similar to hRPTEC cultured in serum-containing conventional medium (hRPTEC-CM). Comparison of leakage and of reabsorption of small molecules for BTD prepared with hRPTEC-SFM (BTD-SFM) with those for our previous BTD prepared with hRPTEC-CM (BTD-CM) showed transportation in these two types of BTD was almost identical. When AKI goats were treated with BTD-SFM for 26 h, increase of survival time and reduction of cytokine expression in blood cells were almost same as for AKI goats treated with BTD-CM. Quantification of the expression of some genes of hRPTEC in BTD revealed significant changes during BTD treatment for AKI goats. In conclusion, lifespan-extended hRPTEC-SFM work as well as hRPTEC-CM, and the biological safety of BTD for patients could be elevated without loss of function by preparation from hRPTEC-SFM.     

Stenosing ureteritis in Henoch–Schönlein purpura: Report of two cases

Stenosing ureteritis (SU), a rare complication of Henoch–Schönlein purpura (HSP), typically presents with severe symptoms. We report the cases of two HSP patients presenting with gross hematuria, blood clotting, and colicky flank pain, followed by purpura on the lower extremities. Early‐stage ultrasonography indicated hydronephrosis, thickened renal pelvic mucous membrane, and ureteral dilatation (UD), suggesting HSP complicated with SU. After early SU treatment with prednisolone, kidney function, thickened renal pelvic mucous membrane, and UD progressively normalized and the pain gradually disappeared. Regular ultrasonography of HSP patients from the onset of gross hematuria can be useful to detect early SU and facilitate conservative therapy with prednisolone. Diagnosis of SU can be easily missed by assuming HSP nephritis, particularly owing to the non‐specific symptoms. Common characteristics as well as treatment methods and prognosis of SU are given in the literature review.     

Some considerations on the biology of pancreatic serous cystadenoma.

Five cases of pancreatic serous cystadenoma were examined pathologically, and their nuclear DNA ploidy patterns were determined. Four were unifocal tumors, and one was a multifocal tumor. The four unifocal tumors were typical serous cystadenomas. However, the multifocal tumor exhibited an increased N/C ratio, irregular nuclear margins, various-sized nuclei, coarse nuclear chromatin, and neural invasion. All tumor cells were stained with antiCA19-9 but none with antiCEA. In the antiCA19-9 staining, the four unifocal tumors and the tumors of the pancreatic tail in the multifocal case were positive only on the apical membrane, whereas the tumor cells of the pancreatic head in the multifocal case were positive within the whole cytosol. The unifocal tumors were diploid with a DNA Index (DI) of 1.0 and proliferation indices (PI) from 4.9 to 20.9% with a mean of 14.4%. In the multifocal case, the tumor in the pancreatic head was aneuploid (DI = 1.9) and had a PI of 27.8%. The multifocal sites in the pancreatic body were aneuploid (DI = 1.9) with a PI of 22.4%. We suggest that the biological property of serous cystadenoma should be revisited.     

Reconstruction of bilateral branch pulmonary artery stenosis caused by Takayasu's aortitis.

A 63 year-old female presented with dyspnea on exertion. Her chest X-ray showed cardiomegaly, and right ventricular overload and tricuspid regurgitation were detected. Her pulmonary ventilation and blood flow scintigraphy findings were suspicious of pulmonary vascular disease; the diagnosis was pulmonary hypertension and bilateral branch pulmonary artery stenosis. After the inflammation settled, the stenotic bilateral branch pulmonary artery was reconstructed with a prosthetic vessel and the pulmonary pressure normalized immediately. A resected specimen revealed that the stenotic changes were from Takayasu's disease. The patient's postoperative course was uneventful, and pulmonary ventilation and blood scintigraphy returned to an almost normal range. At follow-up 5 years and 6 months after the operation, there was no evidence of pulmonary artery disease (eg, stenosis and/or ischemia) or of any change in the central vessels of the retina, the so-called Takayasu's retinopathy.     

Hepatic Circulation and Hepatic Oxygen Consumption in Alcoholic and Nonalcoholic Fatty Liver

The purpose of this study was to determine the differences in hepatic circulation and oxygen consumption in two groups: those with nonalcoholic obesity-related fatty live and those with alcoholic fatty liver. Although the histological degree of fatty infiltration was equal in the two groups, the delta Er569-650, as an index of the regional liver blood flow estimated by spectrophotometric method, was significantly lower in alcoholic fatty liver than in nonalcoholic fatty liver, and the in vivo hepatic oxygen consumption (VO2), also determined by hepatic reflectance spectrophotometry during peritoneoscopy, tended to be lower in alcoholic fatty liver than in nonalcoholic fatty liver. The oxygen saturation of hemoglobin in local liver blood (SO2) was, however, significantly higher in alcoholic fatty liver than in nonalcoholic fatty liver. These results suggest that an increase in oxygen extraction to maintain oxygen consumption, which was indicated by the lowering of the SO2, was not found in alcoholic fatty liver, in spite of a reduction of oxygen supply to the liver. It is concluded that the impairment of hepatic circulation and hepatic oxygen consumption was more serious in alcoholic fatty liver than in nonalcoholic fatty liver, possibly contributing to a different prognosis for the two forms of fatty liver.     

A case of pulmonary sarcoidosis with usual interstitial pneumonia-like lesions distributed predominantly in the lower lung fields]

In 2000, in a 75-year-old man, nodular and reticular opacities were detected in both lower lung fields. He was admitted to our hospital for further examination of these abnormal shadows. Bronchoscopic examination revealed pulmonary sarcoidosis. Prednisolone was prescribed because cardiac sarcoidosis was diagnosed as a clinical complication. In April 2002, the patient visited our hospital for dyspnea on effort. Chest radiography and computed tomography showed nodular and reticular opacities in the right upper lobe, and video-assisted thoracoscopic surgery was performed on the basis of a histological diagnosis. The histological findings of the biopsied specimens revealed a lesion of the type seen in usual interstitial pneumonia, whereas non-caseous granulomas were not detected. His symptoms and chest radiographic findings improved and stabilized with prednisolone and azathioprine. In the present case of pulmonary sarcoidosis, the reticular and nodular opacities predominantly distributed in both lower lung fields, and the histological findings obtained by video-assisted thoracoscopic surgery showed a usual interstitial pneumonia-like lesion. These findings may assist in the understanding of the process of development of pulmonary sarcoidosis.     

Impact of cytomegalovirus serostatus on outcome of unrelated cord blood transplantation for adults: a single-institute experience in Japan

Cytomegalovirus (CMV) disease is one of the major infectious complications after allogeneic hematopoietic stem cell transplantation (SCT). Several studies have shown that CMV-seropositive patients have a substantial survival disadvantage after bone marrow transplantation (BMT) or peripheral blood SCT (PBSCT). Between August 1998 and February 2006, 101 adult patients underwent myeloablative cord blood transplantation (CBT) from unrelated donors at our institution. Sixteen and 85 patients were CMV-seronegative and CMV-seropositive, respectively, prior to CBT. Outcomes of CBT were compared between CMV-seronegative and CMV-seropositive patients. The cumulative incidences of neutrophil engraftment at 60 d after CBT did not differ between CMV-seronegative and CMV-seropositive patients (100% and 94%, P = 0.09); however, the cumulative incidence of platelet engraftment at 100 d was higher in CMV-seronegative patients than CMV-seropositive patients (100% vs. 86%, P < 0.005). The cumulative incidence of CMV antigenemia at 100 d was lower in CMV-seronegative patients than CMV-seropositive patients (0% vs. 77%, P < 0.001); however, the cumulative incidences of CMV disease did not differ between CMV-seronegative and CMV-seropositive patients (0% vs. 1%, P = 0.84). The probabilities of disease-free survival at 2 yr also did not differ between CMV-seronegative and CMV-seropositive patients (92% vs. 72%, P = 0.16). The outcomes of CBT for CMV-seropositive patients as well as CMV-seronegative patients in our series were favorable. This might be due to effective antiviral therapy for CMV infection. Large-scale studies are needed to determine the impact of recipient CMV serostatus on the outcome of CBT for adults.