Oleic acid ameliorates amyloidosis in cellular and mouse models of Alzheimer's disease

Several lines of evidence support protective as well as deleterious effects of oleic acid (OA) on Alzheimer's disease (AD) and other neurological disorders; however, the bases of these effects are unclear. Our investigation demonstrates that amyloid precursor protein (APP) 695 transfected Cos-7 cells supplemented with OA have reduced secreted amyloid-beta (Aβ) levels. An early-onset AD transgenic mouse model expressing the double-mutant form of human APP, Swedish (K670N/M671L) and Indiana (V717F), corroborated our in vitro findings when they were fed a high-protein, low-fat (18% reduction), cholesterol-free diet enriched with OA. These mice exhibited an increase in Aβ40/Aβ42 ratio, reduced levels of beta-site APP cleaving enzyme (BACE) and reduced presenilin levels along with reduced amyloid plaques in the brain. The decrease in BACE levels was accompanied by increased levels of a non-amyloidogenic soluble form of APP (sAPPα). Furthermore, the low-fat/+OA diet resulted in an augmentation of insulin-degrading enzyme and insulin-like growth factor-II. These results suggest that OA supplementation and cholesterol intake restriction in a mouse model of AD reduce AD-type neuropathology.     

Fractal analysis of amyloid plaques in Alzheimer's disease patients and mouse models

The varied morphological and biochemical forms in which amyloid deposits in brain of Alzheimer's disease (AD) patients are complex and their mechanisms of formation are not completely understood. Here we investigated the ability of fractal dimension (FD) to differentiate between the textures of commonly observed amyloid plaques in sporadic and familial AD patients and aged-control individuals as well as in transgenic mouse models of amyloidosis. Studying more than 6000 amyloid plaques immunostained for total Aβ (Aβt), Aβ40 or Aβ42, we show here that Aβ40 FD could efficiently differentiate between (i) AD patients and aged-control individuals (P < 0.001); (ii) sporadic and familial AD due to presenilin-1 or APP (A692G) mutations (P < 0.001); and (iii) three transgenic mouse models of different genotypes (P < 0.001). Furthermore, while diffuse and dense-core plaques present in humans and transgenic mice had comparable FDs, both Aβt and Aβ42 FD could also differentiate diffuse plaques from other plaque types in both species (P < 0.001). Our data suggest that plaque FD could be a valuable tool for objective, computer-oriented AD diagnosis as well as for genotype-phenotype correlations of AD.     

Effect of IL‐6 polymorphism on risk of Alzheimer disease: Genotype‐phenotype association study in Japanese cases

Interleukin‐6 (IL‐6), an inflammatory cytokine might be involved in the pathophysiology of Alzheimer disease (AD); several studies have reported that the “C allele of IL‐6 variable number of tandem repeat polymorphism” (IL‐6vntr) delayed initial onset of AD and also decreased its risk per se. Another polymorphism, G/C allele of IL‐6 gene promoter region (IL‐6prom), is also a candidate because it has an influence on the regulation of plasma IL‐6 concentration. We examined these IL‐6 polymorphisms in 128 Japanese AD cases and 83 control cases using a PCR‐RFLP method. The results showed the frequency of the IL‐6prom G allele was significantly increased in AD, although IL‐6vntr polymorphism was not. Plasma IL‐6 concentration of the AD cases was also significantly higher than that of the control cases. Moreover, the IL‐6prom G allele‐positive AD patients showed a tendency to have higher IL‐6 concentration in the AD group. These findings suggest that the IL‐6prom G allele which may affect plasma IL‐6 concentration might be a risk factor for sporadic AD in Japanese. © 2002 Wiley‐Liss, Inc.     

Multiple‐threshold models for genetic influences on age of onset for Alzheimer disease: Findings in Swedish twins

Twin studies of dementia have typically used relatively simple 2 × 2 contingency tables with one threshold to estimate the relative importance of genetic variance for liability to disease. These designs are inadequate for addressing issues of age at onset, censoring of data, and distinguishing shared environmental effects from age effects. Meyer and Breitner [ 1998 : Am J Med Genet 81:92–97] applied a multiple‐threshold model to the NAS‐NRC Twin Panel (average age of onset, 63.5 years) and report that additive genetic effects and shared environmental effects account for 37% and 35% of the variation, respectively, in age of onset for Alzheimer disease. We apply a modified version of their model to the Study of Dementia in Swedish Twins (average age of onset, 75 years) and find that genetic effects account for 57%–78% of the variance, whereas shared environmental effects are of no importance. Heritability is lower when thresholds are freely estimated rather than fixed to the population prevalences. We interpret the findings to suggest that models with free thresholds confound influences on longevity with influences for the disease. Multiple‐threshold models, however, do not confound age effects with shared environmental influences. © 2001 Wiley‐Liss, Inc.     

Enhanced expression of interferon‐inducible protein‐10 correlates with disease activity and clinical manifestations in systemic lupus erythematosus

Our objective was to investigate the serum levels of interferon‐inducible protein‐10 (IP‐10) in systemic lupus erythematosus (SLE) and their correlation with disease activity and organ manifestations. Serum IP‐10 levels were assessed in 464 SLE patients and 50 healthy donors. Disease activity was assessed by the revised SLE Activity Measure, and the concomitant active organ manifestations, anti‐ds DNA antibody titres, complement levels and erythrocyte sedimentation rates recorded. Peripheral blood mononuclear cell (PBMC) synthesis of IP‐10 in SLE patients and controls was determined by in vitro cultures stimulated with mitogen or lipopolysaccharide. Elevated serum IP‐10 levels were observed in SLE patients, which were significantly higher in the presence of active haematological and mucocutaneous manifestations. SLE PBMCs exhibited enhanced spontaneous IP‐10 production in vitro. Serial IP‐10 levels correlated with longitudinal change in SLE activity, even at low levels where anti‐dsDNA antibody and complement levels remain unchanged. These data demonstrate that IP‐10 levels are increased in SLE and serum IP‐10 may represent a more sensitive marker for monitoring disease activity than standard serological tests.     

Genetic association study between α 1‐antichymotrypsin polymorphism and Alzheimer disease in Chinese Han population

We investigated a common signal peptide polymorphism in the α 1‐antichymotrypsin (ACT) gene in 125 sporadic Alzheimer disease (AD) patients and 141 healthy control subjects in Chinese Han population. We found no significant difference in the distribution of ACT polymorphism between AD cases and controls, and failed to detect any effects of ACT genotypes associated with AD. Thus, our data do not support the involvement of ACT polymorphism in the risk of AD in Chinese Han population. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:133–135, 2000. © 2000 Wiley‐Liss, Inc.     

Prognostic value of COX‐2 immunohistochemical expression evaluated by quantitative image analysis in colorectal cancer

Epidemiological studies have shown that the inducible form of cyclooxygenase (COX‐2) may be involved in colorectal carcinogenesis, but it is controversial whether its expression is a prognostic factor for colorectal cancer. The aim of the study was to examine the expression of COX‐2 in colorectal cancer and investigate its prognostic relevance. Tissue sections of primary tumors from 132 patients undergoing curative resection for colorectal cancer were immunohistochemically examined for COX‐2 expression. The levels of intensity and extent of COX‐2 staining were quantified by use of a computerized image analysis system and correlated with various clinicopathological characteristics and survival. COX‐2 immunoreactivity was observed in the cytoplasm of tumour epithelial cells of all colorectal cancer tissues examined. No significant correlation was found between levels of intensity and extent of COX‐2 staining and various clinicopathological characteristics, including age, gender, tumor location, tumor size, tumor grade, depth of invasion, lymph node status and TNM stage. There was an inverse correlation between intensity and extent of COX‐2 staining scores (Spearman's rho=?0.414; p<0.001). To analyze the prognostic value of intensity and extent of COX‐2 staining, the patients were divided into four groups with respect to quartiles (≤25; >25 to ≤50; >50 to ≤75; and >75). No significant disease‐specific survival difference among the quartiles was found based on analysis of intensity (p=0.689) and extent (p=0.975) of COX‐2 staining. These results suggest that the expression of COX‐2 protein has no significant impact on the outcome of patients with colorectal cancer.     

Low expression of nucleus accumbens‐associated protein 1 predicts poor prognosis for patients with pancreatic ductal adenocarcinoma

Nucleus accumbens‐associated protein 1 (NAC1) is overexpressed in various carcinomas including ovarian, cervical, breast, and pancreatic carcinomas. High expression of NAC1 is considered to have adverse effects on prognosis through negative regulation of growth arrest and DNA‐damage–inducible 45‐γ interacting protein 1 (GADD45GIP1) in ovarian and cervical carcinomas. In the present study, the expression of NAC1 in pancreatic ductal adenocarcinoma (PDA) was measured using immunohistochemistry and computer‐assisted image analysis in order to investigate its correlation with various clinicopathological parameters and prognosis. Patients with low‐NAC1 PDA had worse overall survival (P = 0.0010) and a shorter disease‐free survival (P = 0.0036) than patients with high‐NAC1 PDA. This was a clinical effect opposite to that reported in ovarian and cervical carcinomas. Furthermore, knockdown of NAC1 in pancreatic carcinoma cell lines did not increase expression of the GADD45GIP1 protein. These results indicate that the gene(s) regulated by NAC1 vary depending on the types of carcinoma or originating tissue, and that low expression of NAC1 predicts poor prognosis for patients with PDA.     

Human herpesvirus‐6 in patients with Crohn’s disease

Sura R, Gavrilov B, Flamand L, Ablashi D, Cartun R, Colombel J‐F, Van Kruiningen HJ. Human herpesvirus‐6 in patients with Crohn’s disease. APMIS 2010; 118: 394–400. Human herpesvirus‐6 (HHV‐6) infections are usually asymptomatic reactivations in immunocompetent persons, but may be severe in immunocompromised individuals. Although primary HHV‐6 infection is mainly associated with roseola infantum, it has also been associated with gastroenteritis, diarrhea, and nausea in children. In this study, we investigated the potential role of HHV‐6 in Crohn’s disease (CD). Evidence of HHV‐6 infection in CD patients and controls was determined by immunohistochemistry (IHC), polymerase chain reaction (PCR), and quantitative real‐time PCR (qPCR). Fifty‐one tissue blocks from 23 CD patients and 20 tissue blocks from 20 controls were examined. Quantitativereal‐time PCR was used to assess HHV‐6 viral loads. IHC, PCR and qPCR indicated the presence of HHV‐6 in both CD patients and controls. Immunohistochemistry of tissues revealed an almost equal frequency and distribution of positive cells; however, non‐specific immunostaining confounded interpretation. HHV‐6 DNA was detected in 52% (12/23) of CD and 55% (11/20) of control patients by PCR and in 69.5% (16/23) of CD cases and 65% (13/20) of controls by qPCR. Mean viral load in intestinal tissues was similar in CD and controls (33.4 and 57.9 copies μg^?1 DNA, respectively). Finding equal evidence of HHV‐6 in patients and controls by multiple methods suggests that this virus is ubiquitous and probably not a cause of CD.     

Exosome reduction in vivo is associated with lower amyloid plaque load in the 5XFAD mouse model of Alzheimer's disease

We present evidence here that exosomes stimulate aggregation of amyloid beta (Aβ)1−42 in vitro and in vivo and interfere with uptake of Aβ by primary cultured astrocytes and microglia in vitro. Exosome secretion is prevented by the inhibition of neutral sphingomyelinase 2 (nSMase2), a key regulatory enzyme generating ceramide from sphingomyelin, with GW4869. Using the 5XFAD mouse, we show that intraperitoneal injection of GW4869 reduces the levels of brain and serum exosomes, brain ceramide, and Aβ1−42 plaque load. Reduction of total Aβ1–42 as well as number of plaques in brain sections was significantly greater (40% reduction) in male than female mice. Our results suggest that GW4869 reduces amyloid plaque formation in vivo by preventing exosome secretion and identifies nSMase2 as a potential drug target in AD by interfering with exosome secretion.     

Systematic genetic study of Alzheimer disease in Latin America: Mutation frequencies of the amyloid β precursor protein and presenilin genes in Colombia*

Nearly all mutations in the presenilin 1 (PSEN1), presenilin 2 (PSEN2), and amyloid β precursor protein (APP) genes lead to early‐onset Alzheimer disease (EOAD, onset age at or before 65 years). In order to assess the genetic contribution of these genes in a series of Colombian AD cases, we performed a systematic mutation analysis in 11 autosomal dominant, 23 familial, and 42 sporadic AD patients (34% with age of onset ≤ 65 years). No APP missense mutations were identified. In three autosomal dominant cases (27.2%), two different PSEN1 missense mutations were identified. Both PSEN1 mutations are missense mutations that occurred in early‐onset autosomal AD cases: an I143T mutation in one case (onset age 30 years) and an E280A mutation in two other cases (onset ages 35 and 42 years). In addition, a novel PSEN1 V94M mutation was present in one early‐onset AD case without known family history (onset age 53 years) and absent in 53 controls. The E318G polymorphism was present in five AD cases and absent in controls. In PSEN2, two different silent mutations were detected, including one not reported elsewhere (P129). The majority of the Colombian AD cases, predominantly late‐onset, were negative for PSEN and APP mutations. © 2001 Wiley‐Liss, Inc.     

Identical distribution of the α2‐macroglobulin pentanucleotide deletion in subjects with alzheimer disease and controls in a German population

Recently, an association between a deletion polymorphism in the α2‐macroglobulin gene (A2M) and Alzheimer disease (AD) has been reported. The aim of the present study was to corroborate this association in a German population of 102 AD patients and two control samples of 191 healthy subject and 160 depressed patients. The frequency of the A2M genotype in AD patients was almost identical to that in both control samples. Logistic regression analysis revealed an effect of age and the APOE genotype on AD risk, but no effect of the A2M genotype. Our findings do not support the fact that the previously reported positive association between A2M deletion polymorphism and AD modifies the disease risk in the studied population. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:775–777, 2000. © 2000 Wiley‐Liss, Inc.     

Distribution of the hematopoietic growth factor G‐CSF and its receptor in the adult human brain with specific reference to Alzheimer's disease

The granulocyte colony‐stimulating factor (G‐CSF), being a member of the hematopoietic growth factor family, is also critically involved in controlling proliferation and differentiation of neural stem cells. Treatment with G‐CSF has been shown to result in substantial neuroprotective and neuroregenerative effects in various experimental models of acute and chronic diseases of the central nervous system. Although G‐CSF has been tested in a clinical study for treatment of acute ischemic stroke, there is only fragmentary data on the distribution of this cytokine and its receptor in the human brain. Therefore, the present study was focused on the immunohistochemical analysis of the protein expression of G‐CSF and its receptor (G‐CSF R) in the adult human brain. Since G‐CSF has been shown not only to exert neuroprotective effects in animal models of Alzheimer's disease (AD) but also to be a candidate for clinical treatment, we have also placed an emphasis on the regulation of these molecules in this neurodegenerative disease. One major finding is that both G‐CSF and G‐CSF R were ubiquitously but not uniformly expressed in neurons throughout the CNS. Protein expression of G‐CSF and G‐CSF R was not restricted to neurons but was also detectable in astrocytes, ependymal cells, and choroid plexus cells. However, the distribution of G‐CSF and G‐CSF R did not substantially differ between AD brains and control, even in the hippocampus, where early neurodegenerative changes typically occur.     

Elevated TGFβ–Smad signalling in experimental Pkd1 models and human patients with polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited renal disease characterized by many fluid‐filled cysts and interstitial fibrosis in the kidneys, leading to chronic renal failure. During cystogenesis the renal tubules undergo extensive structural alterations that are accompanied by altered cellular signalling, directly and/or indirectly regulated by the PKD1 and PKD2 proteins. Since transforming growth factor (TGF)‐β signalling modulates cell proliferation, differentiation, apoptosis, adhesion and migration of various cell types, we studied the activation of this signalling pathway in Pkd1‐mutant mouse models at different stages of the disease. Therefore, we analysed expression of the TGFβ–Smad signalling pathway and its target genes in different Pkd1 mutant mouse models in various stages of polycystic disease. Nuclear accumulation of P‐Smad2 in cyst lining epithelial cells was not observed in the initiation phase but was observed at mild and more advanced stages of PKD. This coincides with mild fibrosis and increased mRNA levels of TGFβ target genes, such as fibronectin, collagen type I, plasminogen activator inhibitor 1 and matrix metalloproteinase‐2. At this stage many interstitial fibroblasts were found around cysts, which also showed nuclear localization for P‐Smad2. However, bone morphogenetic protein (BMP) signalling, which can antagonize TGFβ signalling, is not affected, since nuclear expression of P‐Smad1/5/8 and expression of the BMP target gene, inhibitor of DNA binding/differential‐1 (ID‐1) is not altered compared to wild‐type controls. Also, human kidneys with progressive ADPKD showed increased nuclear localization of P‐Smad2, while in general expression of P‐Smad1/5/8 was weak. These results exclude TGFβ signalling at the initiation of cystogenesis, but indicate an important role during cyst progression and in fibrogenesis of progressive ADPKD. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.