Diabetic microangiopathy: pathology and current understanding of its pathogenesis

Recent drastic increase in diabetic population poses serious problems in both health sciences and socioeconomic conditions. The most important issue in the clinical practice of diabetic patients is the treatment and care of chronic complications. It is not fully clear, however, as to the pathophysiology of diabetic microangiopathy and its pathogenesis. Recent studies on microvessel pathology in diabetic patients and molecular analyses on the diabetic animal models disclosed novel features of the dynamic changes of specific organ pathology affected by diabetes and factors involved in its pathogenesis. Under long-term hyperglycemia, early stimuli elicit adaptive reactions of tissues showing acute inflammatory processes of vessel walls and then late irreversible and regressive changes of microangiopathy. Consequently, remodeling of vascular cells and excessive matrix production are cardinal feature. The precise mechanisms of how these tissue changes occur remain speculative; increased polyol pathway, excessive non-enzymatic glycation, increased protein kinase C activity, as well as oxidative stress are all interrelated for the cause and development of the microangiopathy.

Rapidity dependence of charged antihadron to hadron ratios in Au+Au collisions at sqrt[s(NN)]=200 GeV

We present ratios of the numbers of charged antihadrons to hadrons (pions, kaons, and protons) in Au+Au collisions at sqrt[s(NN)]=200 GeV as a function of rapidity in the range y=0-3. While the ratios at midrapidity are approaching unity, the K(-)/K(+) and p;/p ratios decrease significantly at forward rapidities. An interpretation of the results within the statistical model indicates a reduction of the baryon chemical potential from mu(B) approximately 130 MeV at y=3 to mu(B) approximately 25 MeV at y=0.

Limiting temperatures and the equation of state of nuclear matter

From experimental observations of limiting temperatures in heavy ion collisions we derive the critical temperature of infinite nuclear matter Tc=16.6+/-0.86. Theoretical model correlations between Tc, the compressibility modulus K, the effective mass m*, and the saturation density rho s are then exploited to derive the quantity (K/m*)1/2 rho -1/3 s. This quantity together with calculations employing Skyrme and Gogny interactions indicates a value of K in moderately excited nuclei that is in excellent agreement with the value determined from giant monopole resonance data.

Equine herpesvirus-1-induced encephalomyelitis in mice: a comparative study of neuroadapted virus and its parental strain

Little is known about the neuropathogenicity of equine herpesvirus-1 (EHV-1) in mice. No neurological signs were observed in 6-day-old mice inoculated intracerebrally with the HH1 strain (HH1) of EHV-1. However,6-day-old mice inoculated intracerebrally with a variant derived by serial passage of HH1 in mouse brain showed severe neurological symptoms and eventually died. Histological analyses were performed on 6-day-old mice inoculated with the neuroadapted HH1 (NHH1) and the parental HH1 strain by the intracerebral, intranasal or intraperitoneal route. All routes of inoculation with NHH1 caused encephalitis, but myelitis was observed only in mice inoculated intraperitoneally. Prominent histological findings were perivascular cuffing sometimes associated with small fibrin thrombi, neuronal and glial degeneration and necrosis, and intranuclear inclusion bodies in neurons, glial cells and ependymal cells. Intracerebral and intranasal inoculation, but not intraperitoneal inoculation, with HH1 induced central nervous system (CNS) lesions that were milder than those in mice inoculated with NHH1. The distribution of viral antigen was more widespread in mice inoculated with NHH1 than with HH1. No viral antigen was detected in the CNS of mice inoculated intraperitoneally with HH1. These results indicate that increased viral multiplication and spreading in the CNS were responsible for the enhanced neurovirulence of NHH1. Although EHV-1 has been considered to be primarily endotheliotropic in horses, both NHH1 and HH1 showed tropism for the parenchymal cells of the CNS in mice, namely neurons, glial cells and ependymal cells.

Pseudorapidity distributions of charged particles from Au + Au collisions at the maximum RHIC energy, square root[s(NN)] = 200 GeV

We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at square root[s(NN)] = 200 GeV. For the 5% most central events we obtain dN(ch)/deta/(eta = 0) = 625+/-55 and N(ch)/(-4.7< or =eta < or =4.7) = 4630 +/- 370, i.e., 14% and 21% increases, respectively, relative to square root[s(NN)] = 130 GeV collisions. Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity. These results constrain current models of particle production at the highest RHIC energy.

Reduced beta-cell mass and expression of oxidative stress-related DNA damage in the islet of Japanese Type II diabetic patients

AIMS/HYPOTHESIS

We examined the pancreatic islet lesions in Japanese patients with Type II diabetes mellitus to determine if the damage was related to oxidative stress.

METHODS

Morphometric analyses were performed on immunostained sections of the tail portion of the pancreas from 14 diabetic and 15 non-diabetic patients. Amyloid deposition and oxidative stress-induced tissue damage were evaluated by Congo-red staining and immunostaining. Resistance to oxidative stress was assessed from immunostaining results for Cu, Zn-superoxide dismutase (SOD). Expression of (pro)insulin mRNA was assessed by in situ hybridisation.

RESULTS

The pancreas from diabetic patients had amyloid deposition in about 15 % of the islets, intensified reactions of 8-OHdG and HNE, as well as reduced expression of SOD. Islet volume density of beta cells and total beta-cell mass in the pancreas from diabetic patients were reduced by 22 % (p < 0.001) and 30 % (p < 0.05). Islet volume density and total mass of (pro)insulin mRNA-positive cells were similarly reduced in diabetic patients by 22 % (p < 0.001) and 39 % (p < 0.05), respectively. Islet volume density of A cells was increased by 20 % (p < 0.001) but total mass did not change. There were no changes in volume densities of islet, D and PP cells. Reduced beta-cell volume density correlated with increased positive staining of 8-OHdG.

CONCLUSION/INTERPRETATION

Japanese Type II diabetic patients show a reduction of beta-cell mass and evidence of increased oxidative stress-related tissue damage that is correlated with the extent of the beta-cell lesions.

Reduced beta-cell mass and expression of oxidative stress-related DNA damage in the islet of Japanese Type II diabetic patients

AIMS/HYPOTHESIS

We examined the pancreatic islet lesions in Japanese patients with Type II diabetes mellitus to determine if the damage was related to oxidative stress.

METHODS

Morphometric analyses were performed on immunostained sections of the tail portion of the pancreas from 14 diabetic and 15 non-diabetic patients. Amyloid deposition and oxidative stress-induced tissue damage were evaluated by Congo-red staining and immunostaining. Resistance to oxidative stress was assessed from immunostaining results for Cu, Zn-superoxide dismutase (SOD). Expression of (pro)insulin mRNA was assessed by in situ hybridisation.

RESULTS

The pancreas from diabetic patients had amyloid deposition in about 15 % of the islets, intensified reactions of 8-OHdG and HNE, as well as reduced expression of SOD. Islet volume density of beta cells and total beta-cell mass in the pancreas from diabetic patients were reduced by 22 % (p < 0.001) and 30 % (p < 0.05). Islet volume density and total mass of (pro)insulin mRNA-positive cells were similarly reduced in diabetic patients by 22 % (p < 0.001) and 39 % (p < 0.05), respectively. Islet volume density of A cells was increased by 20 % (p < 0.001) but total mass did not change. There were no changes in volume densities of islet, D and PP cells. Reduced beta-cell volume density correlated with increased positive staining of 8-OHdG.

CONCLUSION/INTERPRETATION

Japanese Type II diabetic patients show a reduction of beta-cell mass and evidence of increased oxidative stress-related tissue damage that is correlated with the extent of the beta-cell lesions.

Granulomatous colitis associated with botryomycosis of Propionibacterium acnes

Propionibacterium acnes, an anaerobic, non-spore-forming, gram-positive bacillus, is a common inhabitant of the skin, and its virulence is considered to be low in humans. This report describes an unusual case of granulomatous colitis associated with P acnes infection in a 46-year-old woman. The affected cecum exhibited a tumor histologically characterized by massive transmural infiltrates of small lymphocytes and noncaseating epithelioid granulomas with multinucleated giant cells. Botryomycotic granules were also found in the muscular layer and paracolic connective tissues and consisted of gram-positive bacilli with filamentous growth. Polymerase chain reaction confirmed the presence of P acnes 16S ribosomal DNA in the surgical specimen of the colon. The patient developed a postoperative P acnes-induced peritonitis, which subsided with treatment with antibiotics and surgical drainage. The present case indicates that P acnes is one of the possible pathogens for granulomatous colitis.

beta-Lactoglobulin A with N-ethylmaleimide-modified sulfhydryl residue, polymerized through intermolecular disulfide bridge on heating in the presence of dithiothreitol

Roles of sulfhydryl groups on thermal aggregation of beta-lactoglobulin A (betaLG A) at pH 7.5 were investigated. It is known that betaLG A modified at Cys(121) with N-ethylmaleimide (NEM-betaLG A) does not form an aggregate by heating and that dithiothreitol (DTT) reduces cystine residues and induces the intermolecular sulfhydryl/disulfide interchange reaction and/or oxidation. NEM-betaLG A was heated in the presence of DTT. The molecules were linked together with an intermolecular disulfide bridge, and the polymer formed increased with increase in DTT concentration. The largest portion of polymer was formed when DTT was added at around the same molar concentration as that of NEM-betaLG A. Then, polymer formation decreased with further increase in DTT concentration. The results suggest that sulfhydryl/disulfide residues other than Cys(121), generated from cysteine residues, can induce intermolecular sulfhydryl/disulfide interchange reactions to polymer and that thiol compounds, for example, added DTT, are capable of starting such reactions.

Rapidity dependence of antiproton-to-proton ratios in Au+Au collisions at square root of (sNN) = 130 GeV

Measurements, with the BRAHMS detector, of the antiproton-to-proton ratio at midrapidities and forward rapidities, are presented for Au+Au reactions at square root of [s(NN)] = 130 GeV, and for three different collision centralities. For collisions in the 0%-40% centrality range, we find N(&pmacr;)/N(p) = 0.64+/-0.04((stat))+/-0.06((syst)) at y approximately 0, 0.66+/-0.03+/-0.06 at y approximately 0.7, and 0.41+/-0.04+/-0.06 at y approximately 2. The ratios are found to be nearly independent of collision centrality and transverse momentum. The antiproton and proton rapidity densities vary differently with rapidity, and indicate a significant degree of collision transparency, although a net-baryon free midrapidity plateau (Bjorken limit) is not yet reached.

Reversible conformational change in beta-lactoglobulin A modified with N-ethylmaleimide and resistance to molecular aggregation on heating

beta-Lactoglobulin A (beta LG A) modified with N-ethylmaleimide (NEM-beta LG A) was purified by ion exchange chromatography, and modification of beta LG A by NEM was confirmed by time of flight mass spectrometry and 5,5'-dithiobis(2-nitrobenzoic acid) methods. The fluorescent spectrum of NEM-beta LG A was slightly different from that of native beta LG A. NEM-beta LG A gave no polymerization after heating at 80 degrees C and pH 7.5, as shown by polyacrylamide gel electrophoresis. Conformational change of NEM-beta LG A was observed at 80 degrees C by ultraviolet differential spectra, whereas after cooling it recovered to its original state as before heating, indicating apparent reversible thermal denaturation. Native beta LG A is resistant to pepsin hydrolysis, whereas heated beta LG A was easily hydrolyzed by pepsin. NEM-beta LG A before heating was also resistant to pepsin hydrolysis, and after heating NEM-beta LG A was still resistant to pepsin hydrolysis. These results indicate that NEM-beta LG A maintained a conformation similar to its native form even after heating. Addition of 0.2 M NaCl to the beta LG A heated under salt-free condition induced polymerization of heated beta LG A molecules, but not that of heated NEM-beta LG A. This seemed to indicate that the formation of inter- or intramolecular disulfide linkage made the heat-induced conformational change of beta LG A irreversible.

Effects of OPB-9195, anti-glycation agent, on experimental diabetic neuropathy

BACKGROUND

Nonenzymatic glycation of neural proteins and their end-products (advanced glycation end-products, AGE) have been implicated in the pathogenesis of diabetic neuropathy. We need a development of effective ant-glycation agents for future clinical use.

MATERIALS AND METHODS

We examined the effects of OPB-9195 (OPB), a new inhibitor of glycation, on the peripheral nerve structure and function in diabetic rats. Eight-week-old Wistar rats were made diabetic by streptozotocin (40 mg kg(-1), i.v.) and OPB (60 mg kg(-1) day(-1)) was given by gavage for 24 weeks. Age- and sex-matched normal Wistar rats were used for comparison.

RESULTS

During the experimental period, OPB treatment did not affect the reduced body weight, elevated levels of blood glucose and glycated haemoglobin in diabetic rats. At the end of the experiment, delayed tibial motor nerve conduction velocity was significantly improved (by 60%) in treated diabetic rats, with reduction of serum AGE levels. Expression of immunoreactive AGE in the sciatic nerve was reduced in treated diabetic rats compared with those in untreated rats. Sciatic nerve (Na+, K+)-ATPase activity was also restored in treated diabetic rats. On the cross-sectioned sciatic nerves, positive cells with oxidative stress-related DNA damage, as expressed by 8-hydroxy-2'-deoxyguanosine, were less in the peripheral nerve of treated diabetic rats compared with those of untreated rats.

CONCLUSION

The current study suggested that OPB is beneficial for the reduction of serum AGE and the prevention of diabetic neuropathy.

Pseudolymphoma of the liver associated with Sjögren's syndrome

Sjögren's syndrome (SS) is known to be associated with pseudolymphoma in several organs. We describe a patient with SS complicated by a hepatic pseudolymphoma. Although the development of a hepatic pseudolymphoma is extremely rare, this disorder should be taken into consideration in the differential diagnosis of space occupying lesions related to autoimmune diseases such as SS.

Mice expressing only monosialoganglioside GM3 exhibit lethal audiogenic seizures

Gangliosides are a family of glycosphingolipids that contain sialic acid. Although they are abundant on neuronal cell membranes, their precise functions and importance in the central nervous system (CNS) remain largely undefined. We have disrupted the gene encoding GD3 synthase (GD3S), a sialyltransferase expressed in the CNS that is responsible for the synthesis of b-series gangliosides. GD3S-/- mice, even with an absence of b-series gangliosides, appear to undergo normal development and have a normal life span. To further restrict the expression of gangliosides, the GD3S mutant mice were crossbred with mice carrying a disrupted GalNAcT gene encoding beta1,4-N-acetylgalactosaminyltransferase. These double mutant mice expressed GM3 as their major ganglioside. In contrast to the single mutant mice, the double mutants displayed a sudden death phenotype and were extremely susceptible to induction of lethal seizures by sound stimulus. These results demonstrate unequivocally that gangliosides play an essential role in the proper functioning of the CNS.

Histomorphometric characteristics and cellular kinetics of colorectal polyps with epithelial serrated proliferation adjacent to carcinoma

Four cases of colorectal polyps with epithelial serrated proliferation (CP-ESP) with malignant transformation were studied. In CP-ESP adjacent to carcinoma, if the nuclear size in the surface layer was significantly smaller than those in the bottom and the middle layers of the crypts, the specimen was defined as zone formation positive. If there was no significant difference among the layers, the specimen was defined as zone formation negative. Cell kinetics were evaluated using Ki-67 immunostaining. The CP-ESP regions of cases 1 and 2 showed zone formation with inferior and lateral glandular branching, and were qualitatively hyperplastic on cell kinetics. Cases 3 and 4 showed inferior and lateral glandular branching with no zone formation, and were kinetically neoplastic (adenoma). The histogenesis of hyperplastic polyps with atypia (cases 1 and 2) involves the hyperplastic polyp-carcinoma sequence. In contrast, the development of tubulovillous adenoma or serrated adenoma (cases 3 and 4) may involve the tubulovillous adenoma-carcinoma or serrated adenoma-carcinoma sequence.

[Clinicopathological studies of small-sized advanced large bowel cancer less than 2 cm in diameter]

The small sized lesion of the large bowel advanced cancer has been noticed in the development of the large bowel cancer. In this study, 17 lesions of the large bowel advanced cancer within less than 2 cm in diameter were studied clinicopathologically and histologically, according with PG(polypoid growth), NPG(non polypoid growth) classification and the subclassification of NPG, in which NPG-1 was defined that the height of the adjacent mucosa to the carcinomatous lesion was taller than that of the cancerous lesion, and the NPG except for NPG-1 was defined as NPG-2. And all of 17 lesions were NPG type(NPG-1:9 lesions, NPG-2:8 lesions). The results revealed that NPG-1 lesions were significantly smaller in maximum diameter, the invasion depth of its were deeper, these degree of venous invasion were higher and these carcinomatous differentiation were lower, comparing with those of NPG-2 lesions. In conclusion, it was indicated that the NPG-1 lesion was the large bowel advanced cancer which deeply invaded at the small-sized condition.

Edg-1, the G protein-coupled receptor for sphingosine-1-phosphate, is essential for vascular maturation

Sphingolipid signaling pathways have been implicated in many critical cellular events. Sphingosine-1-phosphate (SPP), a sphingolipid metabolite found in high concentrations in platelets and blood, stimulates members of the endothelial differentiation gene (Edg) family of G protein-coupled receptors and triggers diverse effects, including cell growth, survival, migration, and morphogenesis. To determine the in vivo functions of the SPP/Edg signaling pathway, we disrupted the Edg1 gene in mice. Edg1(-/-) mice exhibited embryonic hemorrhage leading to intrauterine death between E12.5 and E14.5. Vasculogenesis and angiogenesis appeared normal in the mutant embryos. However, vascular maturation was incomplete due to a deficiency of vascular smooth muscle cells/pericytes. We also show that Edg-1 mediates an SPP-induced migration response that is defective in mutant cells due to an inability to activate the small GTPase, Rac. Our data reveal Edg-1 to be the first G protein-coupled receptor required for blood vessel formation and show that sphingolipid signaling is essential during mammalian development.

Microglial activation precedes acute neurodegeneration in Sandhoff disease and is suppressed by bone marrow transplantation

Sandhoff disease is a lysosomal storage disorder characterized by the absence of beta-hexosaminidase and storage of G(M2) ganglioside and related glycolipids in the central nervous system. The glycolipid storage causes severe neurodegeneration through a poorly understood pathogenic mechanism. In symptomatic Sandhoff disease mice, apoptotic neuronal cell death was prominent in the caudal regions of the brain. cDNA microarray analysis to monitor gene expression during neuronal cell death revealed an upregulation of genes related to an inflammatory process dominated by activated microglia. Activated microglial expansion, based on gene expression and histologic analysis, was found to precede massive neuronal death. Extensive microglia activation also was detected in a human case of Sandhoff disease. Bone marrow transplantation of Sandhoff disease mice suppressed both the explosive expansion of activated microglia and the neuronal cell death without detectable decreases in neuronal G(M2) ganglioside storage. These results suggest a mechanism of neurodegeneration that includes a vigorous inflammatory response as an important component. Thus, this lysosomal storage disease has parallels to other neurodegenerative disorders, such as Alzheimer's and prion diseases, where inflammatory processes are believed to participate directly in neuronal cell death.

Pathogenicity of Rhodococcus equi expressing a virulence-associated 20 kDa protein (VapB) in foals

Rhodococcus equi strains of intermediate virulence (IMV) for mice possess a 20kDa protein designated Virulence Associated Protein B (VapB) and a virulence plasmid of 79-100kb, and can be recovered from the submaxillary lymph nodes of pigs. The pathogenicity of such R. equi strains for foals is unknown. In this study, two foals, 42 and 43 days of age, were infected intratracheally with 10(6) and 10(9) cells of R. equi IMV strain A5, respectively. The foal infected with 10(9) cells of strain A5 became clinically ill, with the onset of illness (pyrexia and depression) occurring 21 days after inoculation. R. equi was isolated from the feces and tracheal washings of the foal from 14 to 28 days after inoculation. The foal infected with 10(6) cells of A5 showed no clinical signs, and no R. equi was isolated from any of the samples of feces or tracheal washings during the 28 days of observation. Two foals of 45 and 50 days of age were infected with 10(5) or 10(6) of virulent R. equi ATCC 33701 having 15-17kDa surface proteins designated VapA. Both exhibited severe clinical signs (pyrexia, depression and anorexia) at 12 and 13 days after inoculation. Histopathological examination revealed that strain A5 caused focal granulomatous pneumonia in the foals. R. equi IMV strain A5 was isolated from lung lesions of both foals and from the contents of the intestinal tracts of the foal infected with 10(9) bacteria. These results suggest that IMV R. equi having VapB is less virulent than virulent R. equi having VapA in foals. This finding supports our previous results on the pathogenicities of R. equi strains having these virulence-associated antigens assessed by mouse pathogenicity tests.

Distribution of immunoglobulin isotypes and subisotypes in equine guttural pouch (auditory tube diverticulum)

To clarify the functions of the equine guttural pouch, the distribution of various immunoglobulin isotypes and subisotypes in the guttural pouch mucosa were examined in healthy horses. IgGa was present in the mucosa of guttural pouch, mucosal lymph nodules and submucosal lymph nodules. IgM was scattered in the mucosal lymph nodules and in the germinal centers of the submucosal lymph nodules. IgGc was recognized only in the submucosal lymph nodules. These immunoglobulin isotypes and subisotypes were found in lymphocytes and plasma cells. On the other hand, IgA was detected in glandular epithelial cells and the surface layer of the mucosal epithelium, as well as in free cells. This finding suggests that IgA is secreted through the glandular epithelium. Based on the above findings, we conclude that the guttural pouch has phylactic ability.

Demonstration of equine herpesvirus-1 gene expression in the placental trophoblasts of naturally aborted equine fetuses

Equine herpesvirus-1 (EHV-1) infection was demonstrated in the lung tissue of seven aborted fetuses by immunohistochemical labelling and polymerase chain reaction. The placentas of the fetuses were also examined by non-isotopic in-situ hybridization for the EHV-1 glycoprotein B (gB) gene. Positive hybridization signals were observed in the cytoplasm of trophoblasts, especially in microcotyledons, of all seven placentas, and in villous epithelium of the allantochorion of six placentas. Despite the presence of EHV-1 RNA, EHV-1 antigens were not detected in placentas by immunohistochemical examination. The present study represents the first in-vivo demonstration of the EHV-1 gene in equine trophoblasts. The findings suggest direct cell-to-cell spread of EHV-1 from endometrial cells to trophoblasts.

Histological and morphometrical studies on the mucosa of the equine guttural pouch (auditory tube diverticulum)

The present study attempted to clarify the characteristics of the guttural pouch mucosa in equines and to evaluate its foreign substance clearance ability. The specimens were collected from nine regions (eight in the guttural pouch mucosa, and one in the nasopharynx mucosa). We first examined the pouch mucosa by light and electron microscopy. We then measured the frequency of goblet cells per 200 epithelial cells, the length of the cilia, the thickness of the epithelial cell layer and lamina propria and statistically analyzed the data. The guttural pouch mucosa consisted of stratified columnar epithelia with brush-like cilia, and there were almost no histological differences between adults and foals. The morphometrical study revealed significant differences in goblet cell frequency (p < 0.001) and the thickness of lamina propria (p < 0.05). By contrast, no statistically significant difference was detected in the length of the cilia or the thickness of the epithelial cell layer. These findings suggest that the guttural pouch mucosa provides foreign substance clearance ability, but that its ability varies among different regions of the epithelium.

Conditional up-regulation of MHC class I in skeletal muscle leads to self-sustaining autoimmune myositis and myositis-specific autoantibodies

In the human inflammatory myopathies (polymyositis and dermatomyositis), the early, widespread appearance of MHC class I on the surface of muscle cells and the occurrence of certain myositis-specific autoantibodies are striking features. We have used a controllable muscle-specific promoter system to up-regulate MHC class I in the skeletal muscles of young mice. These mice develop clinical, biochemical, histological, and immunological features very similar to human myositis. The disease is inflammatory, limited to skeletal muscles, self-sustaining, more severe in females, and often accompanied by autoantibodies, including, in some mice, autoantibodies to histidyl-tRNA synthetase, the most common specificity found in the spontaneous human disease, anti-Jo-1. This model suggests that an autoimmune disease may unfold in a highly specific pattern as the consequence of an apparently nonspecific event-the sustained up-regulation of MHC class I in a tissue-and that the specificity of the autoantibodies derives not from the specificity of the stimulus, but from the context, location, and probably the duration of the stimulus. This model further suggests that the presumed order of events as an autoimmune disease develops needs to be reconsidered.