Reduced insulin-induced phosphatidylinositol-3-kinase activation in peripheral blood mononuclear leucocytes from patients with Alzheimer's disease

The epidemiological finding of an increased risk of dementia in patients with diabetes mellitus has raised the hypothesis that a dysfunction of the insulin receptors plays a role in the pathogenesis of Alzheimer's disease (AD). A possible link is suggested by the evidence that the insulin-stimulated phosphatidylinositol-3-kinase (PI-3-K)/phospho-Akt pathway negatively controls the glycogen synthase kinase-3beta. The activation of this enzyme mediates the hyperphosphorylation of the tau protein, a relevant step in the formation of the neurofibrillary tangles associated with AD. We hypothesized that the neurodegeneration associated with AD is related to an impairment of the intracellular signalling stimulated by insulin receptors. To test this hypothesis we assessed the PI-3-K/phospho-Akt pathway following in-vitro challenge with insulin in peripheral blood mononuclear cells from subjects with AD (n = 20) and controls (n = 20). We found that the stimulation of PI-3-K is blunted in patients with AD with respect to control. The reduction did not correlate with the extent of cognitive decline or with scores at neuropsychological tests exploring attention, memory, language or visuospatial abilities. The study supports the hypothesis that an impaired control of glycogen synthase kinase-3beta activity by insulin receptor-mediated signalling plays a role in the pathogenesis of AD, facilitating tau protein phosphorylation and neurofibrillary tangle formation.     

GA2LEN skin test study I: GA²LEN harmonization of skin prick testing: novel sensitization patterns for inhalant allergens in Europe

Background:  Skin prick testing is the standard for diagnosing IgE-mediated allergies. However, different allergen extracts and different testing procedures have been applied by European allergy centres. Thus, it has been difficult to compare results from different centres or studies across Europe. It was, therefore, crucial to standardize and harmonize procedures in allergy diagnosis and treatment within Europe.
Aims:  The Global Asthma and Allergy European Network (GA²LEN), with partners and collaborating centres across Europe, was in a unique position to take on this task. The current study is the first approach to implement a standardized procedure for skin prick testing in allergies against inhalant allergens with a standardized pan-European allergen panel.
Methods:  The study population consisted of patients who were referred to one of the 17 participating centres in 14 European countries ( n  = 3034, median age = 33 years). Skin prick testing and evaluation was performed with the same 18 allergens in a standardized procedure across all centres.
Results:  The study clearly shows that many allergens previously regarded as untypical for some regions in Europe have been underestimated. This could partly be related to changes in mobility of patients, vegetation or climate in Europe.
Conclusion:  The results of this large pan-European study demonstrate for the first time sensitization patterns for different inhalant allergens in patients across Europe. The standardized skin prick test with the standardized allergen battery should be recommended for clinical use and research. Further EU-wide monitoring of sensitization patterns is urgently needed.     

Recommendations for women with lobular carcinoma in situ (LCIS)

Atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS) represent a spectrum of breast disease referred to as "lobular neoplasia" (LN). Although LN occurs relatively infrequently, it is associated with an increased risk of breast cancer, ranging from a three- to four-fold increased risk with ALH up to an eight- to ten-fold increased risk with LCIS. Initially regarded as a direct precursor to invasive lobular carcinoma, LCIS used to be treated by mastectomy. Subsequent studies demonstrating that the risk of invasive disease was conferred bilaterally and that subsequent cancers were of both the ductal and lobular phenotype led to the acceptance of LCIS as a marker of increased risk rather than a true precursor. Today, a diagnosis of LCIS remains one of the greatest identifiable risk factors for the subsequent development of breast cancer. As such, patients are offered one of three options: (1) lifelong surveillance with the goal of detecting subsequent malignancy at an early stage; (2) chemoprevention; or (3) bilateral prophylactic mastectomy. Paralleling changes in the management of invasive breast cancer, trends in the management of LCIS have moved toward more conservative management. However, we have made little progress in understanding the biology of LCIS and therefore remain unable to truly optimize recommendations for individual patients.     

Adenovirus type 5 <Emphasis Type="Italic">E1A</Emphasis>-induced apoptosis in COX-2-overexpressing breast cancer cells

Introduction  

Suppression of Bcl-2 expression can overcome cellular resistance to apoptosis induced by the adenovirus type 5 gene E1A in models of ovarian and breast cancer. Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, is known to downregulate Bcl-2 expression. We hypothesized that celecoxib would enhance E1A-induced apoptosis by suppressing Bcl-2 through suppressing COX-2 expression. If successful, this strategy could represent a means of overcoming resistance to E1A gene therapy.     

Liposome-incorporated Grb2 antisense oligodeoxynucleotide increases the survival of mice bearing bcr-abl-positive leukemia xenografts

We previously demonstrated that liposome-incorporated antisense oligodeoxynucleotide specific for the grb2 mRNA (L-Grb2) inhibited Grb2 protein expression and the proliferation of bcr-abl-positive leukemia cell lines. To determine whether L-Grb2 has the potential of being a therapeutic modality against bcr-abl-positive leukemia, we studied the tissue distribution of L-Grb2 in normal mice before studying its effects in mice bearing bcr-abl-positive leukemia xenografts. L-Grb2 was widely distributed in the body. The highest tissue concentrations of L-Grb2 were found in the spleen and liver, which are the organs where the tumor mass of bcr-abl-positive leukemia is mainly found. At 4 h post-injection, the amount of L-Grb2 detected per g of tissue was 64 microg in spleen and 50 microg in liver. Intravenous injection of bcr-abl-positive 32D mouse leukemia cells into radiated NOD/scid mice caused a lethal leukemia syndrome; we determined whether L-Grb2 could prolong the survival of mice bearing such xenografts. One day after leukemia cell inoculation, mice received twice weekly intravenous injections of L-Grb2. At an injection dose of 15 mg of L-Grb2 per kg of mouse body weight, 80% of mice treated with L-Grb2 survived to 48 days (end of study) whereas 0% of mice treated with the same dose of liposomal control oligonucleotide survived; the mean survival duration of these groups was 44 and 20 days, respectively. Our data indicate that L-Grb2 prolonged the survival of mice bearing bcr-abl-positive leukemia xenografts. L-Grb2 may be used as a novel cancer therapeutic modality.     

"Mitotic drive" of expanded CTG repeats in myotonic dystrophy type 1 (DM1)

In myotonic dystrophy type 1 (DM1), an expanded CTG repeat shows repeat size instability in somatic and germ line tissues with a strong bias toward further expansion. To investigate the mechanism of this expansion bias, 29 DM1 and six normal lymphoblastoid cell lines (LBCLs) were single-cell cloned from blood cells of 18 DM1 patients and six normal subjects. In all 29 cell lines, the expanded CTG repeat alleles gradually shifted toward further expansion by "step-wise" mutations. Of these 29 cell lines, eight yielded a rapidly proliferating mutant with a gain of large repeat size that became the major allele population, eventually replacing the progenitor allele population. By mixing cell lines with different repeat expansions, we found that cells with larger CTG repeat expansion had a growth advantage over those with smaller expansions in culture. This growth advantage was attributable to increased cell proliferation mediated by Erk1,2 activation, which is negatively regulated by p21(WAF1). This phenomenon, which we designated "mitotic drive" , is a novel mechanism which can explain the expansion bias of DM1 CTG repeat instability at the tissue level, on a basis independent of the DNA-based expansion models. The lifespans of the DM1 LBCLs were significantly shorter than normal cell lines. Thus, we propose a hypothesis that DM1 LBCLs drive themselves to extinction through a process related to increased proliferation.     

Ovalbumin‐specific immunoglobulins A and G levels at age 2 years are associated with the occurrence of atopic disorders

Background Humoral responses to food antigens may reflect the propensity of a child's immune system to develop tolerance to innocuous antigens. Early nutrition as well as probiotics may influence these immunological responses. Objective To study the association of humoral responses to early food antigens with the administration of prebiotics and probiotics, with the occurrence of allergy, and with the length of exclusive breastfeeding. Methods In a randomized double‐blind allergy prevention trial in high‐risk children, 1018 mothers took probiotics or placebo from the 36th week of gestation, and their newborn infants received probiotics and prebiotics or placebo during 6 months. At 2 and 5 years, we evaluated the cumulative incidence of allergic diseases (food allergy, eczema, asthma, rhinitis) and sensitization (skin prick test ?3 mm or serum antigen‐specific IgE>0.7 kU/L). In 688 infants at age 2, we measured in sera‐specific IgA, IgG, IgG1, and IgG4 antibody levels to cow's milk (CM), α‐casein (CAS), β‐lactoglobulin (BLG), and ovalbumin (OVA) with ELISA, and specific IgE levels to CM and hen's egg with UniCap. Results Probiotic treatment (n=342) compared with placebo (n=346) showed no effect on serum food‐specific IgA, IgG, IgG1, or IgG4 concentrations at age 2. Atopic children had higher OVA‐IgA (P<0.001), OVA‐IgG (P=0.001), OVA‐IgG1 (P<0.001), and egg‐IgE but lower OVA‐IgG4/egg‐IgE ratio (P<0.001) than non‐atopic children. Longer duration of exclusive breastfeeding (?4 vs. <4 months) was associated with reduced CM‐ and CAS‐specific serum IgA (P<0.001) and IgG levels (P<0.001; P=0.003). Conclusion and Clinical Relevance Allergy was associated with more intense IgA and IgG responses to OVA. Breastfeeding depressed humoral responses, whereas prebiotics and probiotics supplementation showed no immunomodulatory effect. The effect of probiotics on allergies is not mediated through food‐specific antibody responses. Furthermore, OVA‐specific IgA and IgG antibodies may help in assessing the risk for atopy. [Trial registration: Clinicaltrials.gov NCT00298337] Cite this as: A. K. Kukkonen, E. M. Savilahti, T. Haahtela, E. Savilahti and M. Kuitunen, Clinical & Experimental Allergy, 2011 (41) 1414–1421.