Reversal of a hallmark of brain ageing: lipofuscin accumulation

The prospect of removing cellular deposits of lipofuscin is of considerable interest because they may contribute to age related functional decline and disease. Here, we use a decapod crustacean model to circumvent a number of problems inherent in previous studies on lipofuscin loss. We employ (a) validated lipofuscin quantification methods, (b) an in vivo context, (c) essentially natural environmental conditions and (d) a situation without accelerated production of residual material or (e) application of pharmacological compounds. We use a novel CNS biopsy technique that produces both an anti-ageing effect and also permits longitudinal sampling of individuals, thus (f) avoiding conventional purely cross-sectional population data that may suffer from selective mortality biases. We quantitatively demonstrate that lipofuscin, accrued through normal ageing, can be lost from neural tissue. The mechanism of loss probably involves exocytosis and possibly blood transport. If non-disruptive ways to accelerate lipofuscin removal can be found, our results suggest that therapeutic reversal of this most universal manifestation of cellular ageing may be possible.     

Mutations causing aspartylglucosaminuria (AGU): a lysosomal accumulation disease.

This article provides a review of the mutations reported so far in the lysosomal storage disease aspartylglucosaminuria (AGU). The clinical symptoms, biochemical findings, and diagnostic possibilities of the disease are introduced. The prevalence and biological consequences of the found mutations are then described, as well as the availability of a new rapid DNA test suitable for carrier screening. This test will be especially applicable in the genetically isolated Finnish population, where the carrier frequency of AGU was found to be as high as 1:36. Finally, future prospects dealing with the foreseeable therapeutic interventions of the disease are discussed.     

Nuclear retinoid receptor expression in normal human endometrium throughout the menstrual cycle

Previous work has shown that retinoic acid receptors (RARs)and retinoid X receptors (RXRs) are expressed in human endometrialepithelial and stromal cells. These nuclear receptors mediatethe biological effects of retinoic acid, a vitamin A derivativewhich may have an important, though poorly characterized rolein the functional differentiation of secretory eprthelia. Theaim of this study was to find out whether the expression ofRAR and RXR mRNA in endometrial epithelial and stromal cellsvaries in relation to the menstrual cycle. The expression ofRARs and RXRs was investigated by Northern blotting and, forstromal cells, there were no differences in expression of RAR-     

Variation in the expression of cellular retinoid binding proteins in human endometrium throughout the menstrual cycle

Human endometrium is a glandular epithelial tissue with a substantialunderlying stroma. Under the influence of ovarian steroids,endometrium undergoes a cyclical pattern of proliferation followedby secretory differentiation. Since retinoids promote the differentiationof many epithelia to secretory phenotypes they may be involvedin controlling the secretory differentiation of human endometrialepithelium. Cytosolic binding proteins for retinol (cellularretinol binding protein) and retinoic acid (cellular retinoicacid binding protein) may play an important part in regulatingthe availability of retinoic acid to its nuclear receptors andwe have therefore asked whether expression of mRNA for theseproteins varies in relation to endometrial differentiation.In a series of 54 endometrial biopsies, both endometrial epithelialand stromal cells expressed mRNA for cellular retinol bindingprotein type I at a constant level throughout the menstrualcycle. Cellular retinoic acid binding protein type II was alsoexpressed but the level of expression varied dramatically, beingelevated in the proltferative phase and depressed during thesecretory phase of the menstrual cycle in both epithelial andstromal cells. These data suggest that cytosolic binding proteinsmodulate the supply of retinoic acid to the nuclei of endometrialcells during the menstrual cycle and that retinoic acid is involvedin the cyclical control of endometrial differentiation. cellular retinoic acid binding protein/cellular retinol binding protein/endometrium     

Genetics of inflammatory bowel disease: a reappraisal

The advent of advanced molecular biological techniques in the last two decades has allowed the study of genetic factors in inflammatory bowel disease (IBD). A variety of techniques have been employed to elucidate the effects of genes, starting with the clinical observations that IBD is more common in the relatives of patients than the general population, and the consistency of clinical features within families. The situation is likely to be much more complicated than single gene disorders, and it is estimated that between 10 and 20 genes may be involved. Genome scanning techniques using microsatellite markers have been employed to highlight areas of chromosomes linked to disease such as those on chromosomes 12 and 16. In addition association studies of specific genes such as HLA and cytokine genes have been carried out on functional or positional grounds. It is likely that a combination of these techniques will be required to elucidate the role of individual genes. Recently much work has been focused on genes that may determine clinical phenotype such as disease extent or severity or the response to treatment. Identification of these genes may lead to better targeting of therapy and prognostication, and they are likely to be easier to identify than disease susceptibility genes.     

Parcellation of the human pretectal complex: a chemoarchitectonic reappraisal

The pretectum is composed of numerous small nuclei that control various oculomotor functions. In all the non-human mammals investigated, the different pretectal nuclei have been named uniformly according to their structural and functional homology. However, the human pretectal nuclei still bear their traditional, in most cases misleading, nomenclature.In order to reveal the presumed chemoarchitectonic similarities between human and non-human pretectal nuclei, neuropeptide Y (NPY)- and vasoactive intestinal polypeptide (VIP)-immunohistochemistry was performed in the human pretectum, after being utilised successfully for the identification of different pretectal nuclei in the cat. No VIP neurones were observed in the human pretectal area, but numerous NPY cells were found in the 'nucleus lentiformis', and in the anterior bulge of the pretectum, while the 'nucleus sublentiformis' contained an abundant NPY fibre network. Some NPY neurones were present in the 'principal pretectal nucleus' as well. The olivary pretectal nucleus possessed NPY fibres, too. In the accessory optic system, the lateral terminal nucleus contained both NPY and VIP neurones, while in the dorsal terminal nucleus only NPY neurones were found. Our chemoanatomical findings were compared to the standard cytoarchitecture as well.Based on the homotopies in the spatial distribution pattern of NPY neurones in the cat and human pretectum, the current, widely accepted non-human anatomical nomenclature was applied to the morphologically homologous nuclei of the human pretectum. Accordingly, the 'nucleus lentiformis' (which contains numerous NPY cells) corresponds to the nucleus of the optic tract, the 'nucleus sublentiformis' (containing a dense network of NPY fibres) to the posterior pretectal nucleus, and the 'nucleus of the pretectal area' corresponds to the medial pretectal nucleus. We identified the anterior part of the pretectum as the human equivalent of the anterior pretectal nucleus in non-humans, including its two compact and reticular subdivisions. In addition, two accessory optic nuclei were verified chemoarchitectonically in the human brain.     

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) accelerates the accumulation of lipofuscin in mouse adrenal gland

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that causes degeneration of nigrostriatal dopaminergic neurons. Recently, we reported that it also destroys dopaminergic neurons in retina and it induces the accumulation of lipofuscin. We now present morphologic and biochemical evidence that MPTP causes the accumulation of lipofuscin in the adrenal cortex. We speculate, that generation of free radicals during the transformation of MPTP to metabolites might be responsible for lipofuscin formation. MPTP-induced accumulation of lipofuscin may be a useful model for studying the biochemistry of the aging process.     

Distal-proximal somatotopy in the human hand somatosensory cortex: a reappraisal

The distal-proximal representation of the finger and palm in the first somatosensory cortex was reexamined. Somatosensory evoked magnetic fields (SEFs) were measured with a 37-channel first-order axial gradiometer system. Sensory stimulus comprising a 20-ms vibration at a frequency of 200 Hz was delivered to five successive sites in 3-cm increments along the distal-proximal direction over the volar surface of the right index finger and palm. Using a single dipole model, the sources and the signal strengths of the main peak (M50) of the SEFs were estimated. All of the sources were located in the 3b area. There were no statistically significant differences between the locations of dipoles evoked by stimulation of different sites. The results support those of our previous study using a 122-channel whole-head planar gradiometer system that orderly distal-proximal representation of the hand, as described in monkeys, is blurred in the adult human somatosensory cortex. Received: 18 May 99 / Accepted: 28 July 99     

Mutations of signal-transducing G proteins in human disease

Heterotrimeric guanine nucleotide binding proteins (G proteins) couple a large number of cell surface receptors to their intracellular effector molecules, such as enzymes or ion channels. Mutations of G proteins can lead to either activation or inactivation of the corresponding signal transduction pathway and thus cause clinical symptoms. Mutations of heterotrimeric G proteins have been found in a number of endocrine tumors, the McCune-Albright syndrome, Albright's hereditary osteodystrophy, and a combination of precocious puberty and pseudohypoparathyroidism Ia. The identification of the molecular defects underlying the above disorders and the investigation of their functional consequences for metabolism and growth regulation have been the subject of many studies over the past few years. A close understanding of these pathophysiologic mechanisms is crucial for the development of therapeutic strategies.Abbreviations AHO Albright's hereditary osteodystrophy - G protein Guanine nucleotide binding proteins - Gs protein Stimulatory G protein - Gi protein Inhibitory G protein - GHRH Growth hormone releasing hormone - MAS McCune-Albright syndrome - PHP Pseudohypoparathyroidism - PPHP Pseudopseudohypoparathyroidismus - PTH Parathormone     

Molecular aspects of implantation: Variation in the expression of cellular retinoid binding proteins in human endometrium throughout the menstrual cycle

Human endometrium is a glandular epithelial tissue with a substantialunderlying stroma. Under the influence of ovarian steroids,endometrium undergoes a cyclical pattern of proliferation followedby secretory differentiation. Since retinoids promote the differentiationof many epithelia to secretory phenotypes they may be involvedin controlling the secretory differentiation of human endometrialepithelium. Cytosolic binding proteins for retinol (cellularretinol binding protein) and retinoic acid (cellular retinoicacid binding protein) may play an important part in regulatingthe availability of retinoic acid to its nuclear receptors andwe have therefore asked whether expression of mRNA for theseproteins varies in relation to endometrial differentiation.In a series of 54 endometrial biopsies, both endometrial epithelialand stromal cells expressed mRNA for cellular retinol bindingprotein type I at a constant level throughout the menstrualcycle. Cellular retinoic acid binding protein type II was alsoexpressed but the level of expression varied dramatically, beingelevated in the proliferative phase and depressed during thesecretory phase of the menstrual cycle in both epithelial andstromal cells. These data suggest that cytosolic binding proteinsmodulate the supply of retinoic acid to the nuclei of endometrialcells during the menstrual cycle and that retinoic acid is involvedin the cyclical control of endometrial differentiation.     

Age changes in the lipofuscin content of the human heart muscle

summary Ontogenetic dynamics of lipfuscin in the human heart muscle were studied by the method of planimetric measurements. The hearts of one hundred cadavers of the age from 28 weeks up to 82 years were investigated. Beginning with the second decade of life lipofuscin is present on the myocardium of every individual, no matter what the cause of his death was: an occasional trauma or an infectious disease. Deposition of lipofuscin is most intense during the first half of the life span (up to 40 years), most of all, at the beginning of its appearance. Data collected indicate that lipofuscin deposition is a physiological phenomenon and is not caused by aging processes of the organism.Presented by V. A. Engelhardt, Active Member of the USSR Academy of Medical Sciences     

Molecular analysis of the ABCA4 gene in Turkish patients with Stargardt disease and retinitis pigmentosa

The clinical importance of sequence variations in the ABCA4 gene has been extensively discussed during the last decade. Mutations in the ABCA4 gene are involved in several forms of inherited retinal degenerations. We screened all 50 exons of the ABCA4 gene in a cohort of 5 Stargardt Disease (STGD) and 35 autosomal recessive retinitis pigmentosa (arRP) patients of Turkish descent to assess the nature of ABCA4 mutant alleles in this population. Our results revealed the presence of three novel mutations: c.160T>G (p.C54G), c.2486C>T (p.T829M), and c.973-6C>A; two mutations previously reported, c.634C>T (p.R212C) and c.4253+4C>T, and several polymorphic changes in the ABCA4 gene among Turkish patients affected with Stargardt and arRP. To our knowledge this report represents the first published study of ABCA4 mutations in the Turkish population resulting in STGD.     

Anxiety and plasma cortisol at the crest of the circadian cycle:reappraisal of a classical hypothesis.

Near-maximal anxiety by subjective and behavioral criteria was evoked and terminated in phobic patients by initiation and termination of rapid live confrontation ("flooding in vivo") with the specific stimulus that each avoided, at a time approximating the crest of the circadian cycle of adrenal cortical function. The procedure was associated with moderate, but not marked, elevations of plasma cortisol above control levels in some, but not all, subjects. Differences in anxiety levels as self-rated by the patients did not account for differences in cortisol response. The findings should stimulate further reevaluation of the hypothesis that affective arousal is the key psychological determinant of adrenal cortical function. Dissociation between subjective-behavioral arousal and plasma cortisol during flooding may be a manifestation of what behavior therapists call "desynchrony of fear."     

Coexpression of intermediate filaments in normal and neoplastic human tissues: a reappraisal

The current view that coexpression of intermediate filaments (IFs) must be considered a bizarre and unpredictable phenomenon, which seriously jeopardizes the use of their localization in diagnostic applications, is critically reviewed in light of the evidence so far acquired by investigations in vivo and in vitro. A less dogmatic approach, which considers IF expression the result of a series of interactions between cells and their microenvironment instead of a function of their histogenesis, not only justifies the complex variety of coexpressions observed in normal and neoplastic tissues but also confirms the usefulness of IF expression in diagnostic applications and offers new opportunities for investigations, with special regard to immunoelectron microscopy.     

Changes in nerve cells of the nucleus basalis of Meynert in Alzheimer's disease and their relationship to ageing and to the accumulation of lipofuscin pigment

The number of nerve cells in the nucleus basalis of Meynert in normally aged persons is reduced by 30% by 90 years of age and cytoplasmic RNA content and nucleolar volume by about 20%. In Alzheimer's disease the changes are greatly exacerbated, with the cell number being depleted by a further 60% and cytoplasmic RNA content and nucleolar volume by an extra 35%. Moreover, younger patients with Alzheimer's disease show a much greater difference from controls of the same age than do older patients; indeed, by 90 years of age the levels of these changes are similar in Alzheimer's disease and in old age alone. Lipofuscin content is increased to a similar extent with age in both Alzheimer's disease and control patients and was associated with loss of cytoplasmic RNA content and nucleolar volume in both groups. It is suggested that mechanisms which result in the accumulation of this pigment during life also lower the capability of cells of the nucleus basalis of Meynert to withstand disease pathogens, leading to a certain degree of change in old age alone and one which in other persons may be compounded by secondary factors giving the extreme degeneration of Alzheimer's disease.     

Mutations and nuclear accumulation of beta-catenin correlate with intestinal phenotypic expression in human gastric cancer

AIMS: Abnormal localization of beta-catenin is frequently observed in human gastric cancers. The aim of the present study was to evaluate relationships among gastrointestinal differentiation phenotypes, beta-catenin localization and mutations of Wnt signalling genes. METHODS AND RESULTS: Seventy-seven regions in 39 gastric adenocarcinomas were classified according to beta-catenin localization and gastric and intestinal phenotypes. Cases with membranous beta-catenin localization showed a gradual decrease from gastric (G) (55% = 6/11) and gastric-and-intestinal-mixed (GI) (17% = 5/29) to intestinal (I) (0% = 0/21) phenotypes, while those with nuclear localization showed a concomitant increase: 18% (2/11), 41% (12/29), 95% (20/21) and 63% (10/16) for G, GI, I and null type (N), respectively (P < 0.001, membranous versus nuclear localization in G, GI through I). Mutations in exon 3 of the beta-catenin gene were found in G (50% = 1/2), GI (67% = 8/12), I (45% = 9/20) and N (0% = 0/10) regions with nuclear beta-catenin localization (GI versus N, P < 0.01; I versus N, P < 0.05). Adenomatous polyposis coli (APC) gene mutations were demonstrated only in GI, I and N types, irrespective of beta-catenin localization. Molecular analysis of these genes revealed 10 tumours to be heterogeneous out of 16 informative cases (62.5%). CONCLUSION: Intestinal phenotypic expression is accompanied by a shift from membranous to cytoplasmic/nuclear accumulation of beta-catenin. In contrast, N-type regions may progress along a different pathway.     

Mutations and sequence variation in the human myosin heavy chain IIa gene (MYH2)

We recently described a new autosomal dominant myopathy associated with a missense mutation in the myosin heavy chain (MyHC) IIa gene (MYH2). In this study, we performed mutation analysis of MYH2 in eight Swedish patients with familial myopathy of unknown cause. In two of the eight index cases, we identified novel heterozygous missense mutations in MYH2, one in each case: V970I and L1061V. The mutations were located in subfragment 2 of the MyHC and they changed highly conserved residues. Most family members carrying the mutations had signs and symptoms consisting mainly of mild muscle weakness and myalgia. In addition, we analyzed the extent and distribution of nucleotide variation in MYH2 in 50 blood donors, who served as controls, by the complete sequencing of all 38 exons comprising the coding region. We identified only six polymorphic sites, five of which were synonymous polymorphisms. One variant, which occurred at an allele frequency of 0.01, was identical to the L1061V that was also found in one of the families with myopathy. The results of the analysis of normal variation indicate that there is strong selective pressure against mutations in MYH2. On the basis of these results, we suggest that MyHC genes should be regarded as candidate genes in cases of hereditary myopathies of unknown etiology.     

Induction of the ganglion cell differentiation program in human retinal progenitors before cell cycle exit

Background: Despite the disease relevance, understanding of human retinal development lags behind that of other species. We compared the kinetics of gene silencing or induction during ganglion cell development in human and murine retina. Results: Induction of POU4F2 (BRN3B) marks ganglion cell commitment, and we detected this factor in S‐phase progenitors that had already silenced Cyclin D1 and VSX2 (CHX10). This feature was conserved in human and mouse retina, and the fraction of Pou4f2⁺ murine progenitors labeled with a 30 min pulse of BrdU matched the fraction of ganglion cells predicted to be born in a half‐hour period. Additional analysis of 18 markers revealed many with conserved kinetics, such as the POU4F2 pattern above, as well as the surprising maintenance of “cell cycle” proteins KI67, PCNA, and MCM6 well after terminal mitosis. However, four proteins (TUBB3, MTAP1B, UCHL1, and RBFOX3) showed considerably delayed induction in human relative to mouse retina, and two proteins (ISL1, CALB2) showed opposite kinetics, appearing on either side of terminal mitosis depending on the species. Conclusion: With some notable exceptions, human and murine ganglion cell differentiation show similar kinetics, and the data add weight to prior studies supporting the existence of biased ganglion cell progenitors. Developmental Dynamics 243:712–729, 2014. © 2013 Wiley Periodicals, Inc.     

Accumulation of cardiac lipofuscin in mammals: correlation between sexual maturation and the first appearance of lipofuscin

Accumulation of lipofuscin is an important phenomenon of the cellular aging process. The first appearance of cardiac lipofuscin showed a good correlation with sexual maturation, which was correlated with maximum life-span of mammals. Large metabolic changes occurred at sexual maturation. From these results, it is suggested that sexual maturation of mammals is the initiation period of the aging process. Correlation between sexual maturation and longevity was re-evaluated using many mammals. Domestic and laboratory animals showed an earlier sexual maturation than other mammals, including rodents.     

In vitro synthesis of human IgE: reappraisal of a 5-year study

In the last 5 years some models of human IgE production in vitro have been investigated in our laboratory. Spontaneous IgE synthesis was found in cultures of B cells from most patients with atopic dermatitis or atopic patients with multiple sensitivities and from some patients with pollenosis, but only during the pollination period. A small and variable increase of the spontaneous IgE synthesis was induced by soluble factor(s) produced by T cells from patients with severe atopy. Selected helper T cell clones were also able to induce IgE synthesis in vitro by both atopic and normal B cells.