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Biomedical subjects

Hannelore Ehrenreich

Publications and source records attributed to Hannelore Ehrenreich.

At least 19 recordsLinked to original sources
PubMed2006

Recovery of hippocampus-related functions in chronic alcoholics during monitored long-term abstinence.

AIMS: The hippocampus (HC) is characterized by high vulnerability to noxious influence, but also by a considerable regenerative potential. Although deficits in HC-related functions are among the most commonly reported cognitive sequelae in alcoholism, little and conflicting information is available concerning regeneration upon abstinence. The present study has been designed to evaluate (i) the frequency of measurable dysfunction in so called HC tests and (ii) its predictive value for risk to relapse in a cohort of 50 severely affected chronic alcoholic patients and (iii) to monitor recovery of HC-related functions upon strict abstention from alcohol. METHODS: Patients underwent a 2-year neuropsychological follow-up including HC-associated tests (Verbal Learning Test, VLT; Nonverbal Learning Test, NVLT; 'City Map Test' of Learning and Memory Test, LGT-3), as well as tests of intelligence and attention in the framework of OLITA (Outpatient Long-Term Intensive Therapy for Alcoholics), a programme with careful abstinence monitoring. RESULTS: At study entry, 30/50 (60%) alcoholics had HC dysfunction which tended to predict a lower long-term abstinence probability (P = 0.058). Of the subgroup that could be followed under conditions of strictly monitored alcohol abstinence (n = 32; age 44.7 +/- 6.2 years; 23 men, 9 women), 53% (17/32) exhibited distinct HC dysfunction at inclusion which returned to normal after 2 years. Patients with initially normal HC function (9/32) and patients with additional brain damage of different aetiologies (6/32) failed to show improvement on HC-related tests. While the former displayed stably normal HC test performance, the latter remained on a performance level below normal. CONCLUSIONS: Demonstrating slow but remarkable regeneration of HC functions upon strict abstention from alcohol, our data strongly support abstinence-oriented long-term treatment of alcoholics. The absence of functional recovery in patients with additional causes of brain damage might be explained by the 'dual hit' exhausting the regenerative potential of the HC.

Adult↗
PubMed2006

Cell type specific signalling by hematopoietic growth factors in neural cells.

Correct timing and spatial location of growth factor expression is critical for undisturbed brain development and functioning. In terminally differentiated cells distinct biological responses to growth factors may depend on cell type specific activation of signalling cascades. We show that the hematopoietic growth factors thrombopoietin (TPO) and granulocyte colony-stimulating factor (GCSF) exert cell type specific effects on survival, proliferation and the degree of phosphorylation of Akt1, ERK1/2 and STAT3 in rat hippocampal neurons and cortical astrocytes. In neurons, TPO induced cell death and selectively activated ERK1/2. GCSF protected neurons from TPO- and hypoxia-induced cell death via selective activation of Akt1. In astrocytes, neither TPO nor GCSF had any effect on cell viability but inhibited proliferation. This effect was accompanied by activation of ERK1/2 and inhibition of STAT3 activity. A balance between growth factors, their receptors and signalling proteins may play an important role in regulation of neural cell survival.

Animals↗
PubMed2006

Erythropoietin in the cerebrospinal fluid in neurodegenerative diseases.

Erythropoietin (EPO) and its specific receptor (EPOR) have been proposed to act as an endogenous system protecting against neuronal injury and neurodegeneration. We measured EPO in cerebrospinal fluid (CSF) of patients with neurodegenerative diseases, and tested for a correlation with an established biomarker of neuro-axonal damage, tau protein. Patients with Alzheimer's disease (AD, N=40), vascular dementia (VD, N=19), frontotemporal lobe dementia (FTLD, N=5), ALS (N=30) and controls (N=49) were included. Cerebrospinal fluid and serum levels of EPO and tau were measured using ELISA techniques. We found CSF EPO in ALS to be lower than in controls (p=0.04), while no difference between patients with AD, VD, FTLD and controls was detectable. CSF EPO correlated with age (p<0.001) as well as with tau protein (p=0.002) in all patients pooled. In contrast to the upregulation of the EPO/EPOR system in brain tissue upon various conditions of neuronal distress, CSF EPO concentrations in neurodegenerative disease were found in the same range or even reduced as compared to controls. This may be due to a relative deficiency of endogenous CNS EPO in these conditions and/or to a more efficient extraction of free EPO molecules from brain intercellular fluid by increased numbers of EPOR.

Aged↗
PubMed2006

Arginine challenge unravels persistent disturbances of urea cycle and gluconeogenesis in abstinent alcoholics.

AIMS: Data on recovery from hormonal and metabolic sequelae of alcoholism in strictly controlled alcohol abstinence are mainly restricted to short-term abstention. Our previous findings of persistently decreased plasma and urinary urea concentrations in long-term abstinent alcoholics prompted us to further elucidate this unexplained phenomenon. METHODS: The response of circulating urea cycle metabolites and glucose-regulating hormones to an intravenous load (30 g) of arginine hydrochloride was investigated in abstinent male alcoholics (n = 14) after complete recovery of all routine liver parameters and compared with that in healthy male controls (n = 15). RESULTS: The arginine challenge provoked (i) higher peak concentrations of arginine and increased arginine/ornithine and ornithine/citrulline ratios in the plasma of abstinent alcoholics; (ii) augmented plasma glutamine concentrations in alcoholics in the presence of comparable levels in both experimental groups of plasma glutamate, ammonia, and nitrate/nitrite; (iii) parallel increases in plasma urea concentrations over the respective baseline levels but distinctly higher urinary urea excretion in controls; (iv) a blunted blood glucose response to arginine in alcoholics together with a reduced insulin and glucagon surge; and (v) an elevated growth hormone peak as compared with controls. CONCLUSIONS: Application of an intravenous arginine challenge reveals profound and lasting metabolic and hormonal disturbances in abstinent alcoholics, affecting urea cycle and gluconeogenesis. The common denominator of many of these changes may be an acquired irreversible deficiency in cellular energy regulation.

Adult↗
PubMed2006

The brain erythropoietin system and its potential for therapeutic exploitation in brain disease.

The discovery of the broad neuroprotective potential of erythropoietin (EPO), an endogenous hematopoietic growth factor, has opened new therapeutic avenues in the treatment of brain diseases. EPO expression in the brain is induced by hypoxia. Practically all brain cells are capable of production and release of EPO and expression of its receptor. EPO exerts multifaceted protective effects on brain cells. It protects neuronal cells from noxious stimuli such as hypoxia, excess glutamate, serum deprivation or kainic acid exposure in vitro by targeting a variety of mechanisms and involves neuronal, glial and endothelial cell functions. In rodent models of ischemic stroke, EPO reduces infarct volume and improves functional outcome, but beneficial effects have also been observed in animal models of subarachnoid hemorrhage, intracerebral hemorrhage, traumatic brain injury, and spinal cord injury. EPO has a convenient therapeutic window upon ischemic stroke and favorable pharmacokinetics. Results from first therapeutic trials in humans are promising, but will need to be validated in larger trials. The safety profile and effectiveness of EPO in a wide variety of neurologic disease models make EPO a candidate compound for a potential first-line therapeutic for neurologic emergencies.

Animals↗
PubMed2006

Follow-up of 180 alcoholic patients for up to 7 years after outpatient treatment: impact of alcohol deterrents on outcome.

OBJECTIVE: (1) To perform a 9-year study of abstinence, lapse, and relapse in 180 chronic alcoholic patients, participants of the Outpatient Longterm Intensive Therapy for Alcoholics (OLITA); (2) To investigate the role of supervised alcohol deterrents (AD) in relapse prevention and as an adjunct for maintenance of long-term abstinence. METHOD: This prospective open treatment study evaluates the long-term course of drinking outcomes and AD use of 180 chronic alcoholics consecutively admitted from 1993 to 2002. Subsamples are compared for (1) sham-AD versus verum-AD (disulfiram/calcium carbimide), (2) coped lapses versus finally detrimental lapses versus malignant relapses, and (3) AD use for 13 to 20 versus >20 months. RESULTS: In this 9-year study, the cumulative probability of not having relapsed was 0.52, and that of not having consumed any alcohol was 0.26. Despite long-term use, disulfiram/calcium carbimide was well tolerated. Patients on sham-AD (due to contraindications to verum-AD) showed higher cumulative abstinence probability than patients on verum (S = 0.86 vs. S = 0.49, p = 0.03). Detrimental lapses and malignant relapses occurred earlier than successfully coped lapses (p < 0.001); patients with detrimental lapse and with malignant relapse had fewer days of AD intake and less subsequent days without AD than patients with coped lapse (p < 0.001). The cumulative abstinence probability was S = 0.75 for patients with long-term intake compared with S = 0.50 for patients who stopped AD between months 13 and 20 (p < 0.001). CONCLUSIONS: An abstinence rate of >50% in this 9-year study strongly supports the concept of comprehensive, long-term outpatient treatment of alcoholics. Supervised, guided intake of AD, also over extended periods, can be used as a predominantly psychologically acting ingredient of successful alcoholism therapy.

Adult↗
PubMed2006

Reduced oxidative damage in ALS by high-dose enteral melatonin treatment.

Amyotrophic lateral sclerosis (ALS) is the collective term for a fatal motoneuron disease of different etiologies, with oxidative stress as a common molecular denominator of disease progression. Melatonin is an amphiphilic molecule with a unique spectrum of antioxidative effects not conveyed by classical antioxidants. In preparation of a possible future clinical trial, we explored the potential of melatonin as neuroprotective compound and antioxidant in: (1) cultured motoneuronal cells (NSC-34), (2) a genetic mouse model of ALS (SOD1(G93A)-transgenic mice), and (3) a group of 31 patients with sporadic ALS. We found that melatonin attenuates glutamate-induced cell death of cultured motoneurons. In SOD1(G93A)-transgenic mice, high-dose oral melatonin delayed disease progression and extended survival. In a clinical safety study, chronic high-dose (300 mg/day) rectal melatonin was well tolerated during an observation period of up to 2 yr. Importantly, circulating serum protein carbonyls, which provide a surrogate marker for oxidative stress, were elevated in ALS patients, but were normalized to control values by melatonin treatment. This combination of preclinical effectiveness and proven safety in humans suggests that high-dose melatonin is suitable for clinical trials aimed at neuroprotection through antioxidation in ALS.

Adult↗
PubMed2006

Personality disorder and chronicity of addiction as independent outcome predictors in alcoholism treatment.

OBJECTIVE: A prospective four-year study examined which components of addiction severity predicted time to relapse among 112 adults with chronic alcoholism who participated in a comprehensive outpatient treatment program. METHODS: Recruited from emergency, inpatient, and outpatient facilities, patients were admitted into the program consecutively between March 1998 and June 2002. Alcohol abstinence was carefully monitored for four years from admission by regular contacts and urine and blood analyses. Alcoholism characteristics and personality disorders were assessed with structured interviews and the International Diagnostic Checklists for Personality Disorders. RESULTS: Among a variety of potential variables, only presence of a personality disorder and chronicity of addiction were independently associated with a decrease of cumulative four-year abstinence probability. CONCLUSIONS: Their high predictive values suggest that chronicity and personality disorder rank among the most important characteristics of addiction severity.

Alcoholism↗
PubMed2005

Global brain atrophy after unilateral parietal lesion and its prevention by erythropoietin.

In humans, neurotrauma is suspected to cause brain atrophy and accelerate slowly progressive neurodegenerative disorders, such as Alzheimer's disease or schizophrenia. However, a direct link between brain injury and subsequent delayed global neurodegeneration has remained elusive. Here we show that juvenile (4-week-old) mice that are given a discrete unilateral lesion of the parietal cortex, develop to adulthood without obvious clinical symptoms. However, when monitored 3 and 9 months after lesioning, using high-resolution three-dimensional MRI and behavioural testing, the same mice display global neurodegenerative changes. Surprisingly, erythropoietin, a haematopoietic growth factor with potent neuroprotective activity, prevents behavioural abnormalities, cognitive dysfunction and brain atrophy when given for 2 weeks after acute brain injury. This demonstrates that a localized brain lesion is a primary cause of delayed global neurodegeneration that can be efficiently counteracted by neuroprotection.

Acute Disease↗
PubMed2005

Expression patterns of erythropoietin and its receptor in the developing spinal cord and dorsal root ganglia.

Recombinant human erythropoietin (EPO) is neuroprotective in animal models of adult spinal cord injury, and reduces apoptosis in adult dorsal root ganglia after spinal nerve crush. The present work demonstrates that spinal cord and dorsal root ganglia share dynamic expression patterns of EPO and its receptor (EPOR) during development. C57Bl mice from embryonic days (E) 8 (E8) to E19 were studied. In spinal cord and dorsal root ganglia, EPOR expression in all precursor cells preceded the expression of EPO in subsets of neurons. On E11, EPO-immunoreactive spinal motoneurons and ganglionic sensory neurons resided adjacent to EPOR-expressing radial glial cells and satellite cells, respectively. From E12 onwards, EPOR-immunoreactivity decreased in radial glial cells and, transiently, in satellite cells. Simultaneously, large-scale apoptosis of motoneurons and sensory neurons started, and subsets of neurons were labelled by antibodies against EPOR. Viable neurons expressed EPO and EPOR. Up to E12.5, apoptotic cells were EPOR-immunopositive, but variably EPO-immunonegative or EPO-immunopositive. Thereafter, EPO-immunonegative and EPOR-immunopositive apoptotic cells predominated. Our findings suggest that EPO-mediated neuron-glial and, later, neuron-neuronal interactions promote the differentiation and/or the survival of subsets of neurons and glial cells in central as well as in peripheral parts of the embryonic nervous system. Correspondingly, expression of phospho-Akt-1/protein-kinase B extensively overlapped expression sites of EPO and EPOR, but was absent from apoptotic cells. Identified other sites of EPO and/or EPOR expression include radial glial cells that transform to astrocytes, cells of the floor plate and notochord as well as neural crest-derived boundary cap cells at motor exit points and cells of the primary sympathetic chain.

Animals↗
PubMed2005

A hematopoietic growth factor, thrombopoietin, has a proapoptotic role in the brain.

Central nervous and hematopoietic systems share developmental features. We report that thrombopoietin (TPO), a stimulator of platelet formation, acts in the brain as a counterpart of erythropoietin (EPO), a hematopoietic growth factor with neuroprotective properties. TPO is most prominent in postnatal brain, whereas EPO is abundant in embryonic brain and decreases postnatally. Upon hypoxia, EPO and its receptor are rapidly reexpressed, whereas neuronal TPO and its receptor are down-regulated. Unexpectedly, TPO is strongly proapoptotic in the brain, causing death of newly generated neurons through the Ras-extracellular signal-regulated kinase 1/2 pathway. This effect is not only inhibited by EPO but also by neurotrophins. We suggest that the proapoptotic function of TPO helps to select for neurons that have acquired target-derived neurotrophic support.

Animals↗
PubMed2005

Hippocampal cannabinoid-1 receptor upregulation upon endothelin-B receptor deficiency: a neuroprotective substitution effect?

Endothelin (ETB)-receptors mediate anti-apoptotic actions. Lack of functional ETB-receptors leads to increased neuronal apoptosis in the hippocampus. The increased apoptosis must be compensated by other mechanisms, however, as ETB-deficient rats display normal overall brain morphology. To illuminate on brain plasticity in ETB-receptor deficiency, we studied the expression and function of another neuroprotective system, the cannabinoid CB1-receptors, in ETB-deficient hippocampus. We show that CB1 expression in hippocampus increases postnatally in all rats but that the increase in CB1-receptor expression is significantly higher in ETB-deficient compared to wildtype littermates. Neuronal apoptosis decreases during brain maturation but remains on a significantly higher level in the ETB-deficient compared to wildtype dentate. When investigating survival of hippocampal neurons in culture, we found significant protection against hypoxia-induced cell death with CB1-analogs (noladin, (9-tetrahydrocannabinol) only in ETB-deficient neurons. We suggest that CB1-receptor upregulation in the ETB-mutant hippocampus reflects an attempt to compensate for the lack of ETB-receptors.

Animals↗
PubMed2005

Mast cells and endothelin-1: a life-saving biological liaison?

Over a decade ago endothelin-1 (ET-1) was described as belonging to the assortment of mast cell-derived and mast cell-bound cytokines. Mast cell subtype- and environment-dependent, ET-1 acts as a potent non-immunological mast-cell activator, which leads to degranulation and mediator release. The biological significance of this phenomenon remained obscure; however, a recent report sheds new light on this delicate mast cell-ET-1 connection. The authors of this report use mast cell-deficient mice to provide convincing evidence that mast cells counteract the toxicity induced by high concentrations of ET-1, and thereby promote homeostasis.

Animals↗
PubMed2005

In vitro gender differences in neuronal survival on hypoxia and in 17beta-estradiol-mediated neuroprotection.

Gender differences in neuropsychiatric disease are recognized but not well understood. Investigating the survival of primary rat hippocampal neurons in culture, we found significant and inverted gender differences on normoxia versus hypoxia. Male cells were more resistant under normoxia but more vulnerable under hypoxia than female cells. Male vulnerability pattern was acquired in cells from neonatally testosterone-primed females. Estrogens, acting via membrane receptors, had a higher neuroprotective power in male neurons, explained at least in part by the pronounced increase in estrogen receptor beta/alpha ratio during hypoxia in male cells only.

Animals↗
PubMed2004

Combined therapy with methylprednisolone and erythropoietin in a model of multiple sclerosis.

Neurodegenerative processes determine the clinical disease course of multiple sclerosis, an inflammatory autoimmune CNS disease that frequently manifests with acute optic neuritis. None of the established multiple sclerosis therapies has been shown to clearly reduce neurodegeneration. In a rat model of experimental autoimmune encephalomyelitis, we recently demonstrated increased neuronal apoptosis under methylprednisolone therapy, although CNS inflammation was effectively controlled. In the present study, we combined steroid treatment with application of erythropoietin to target inflammatory as well as neurodegenerative aspects. After immunization with myelin oligodendrocyte glycoprotein (MOG), animals were randomly assigned to six treatment groups receiving different combinations of erythropoietin and methylprednisolone, or respective monotherapies. After MOG-induced experimental autoimmune encephalomyelitis became clinically manifest, optic neuritis was monitored by recording visual evoked potentials. The function of retinal ganglion cells, the neurons that form the axons of the optic nerve, was measured by electroretinograms. Functional and histo pathological data of retinal ganglion cells and optic nerves revealed that neuron and axon protection was most effective when erythropoietin treatment that was started at immunization was combined with high-dose methylprednisolone therapy given from days 1 to 3 of MOG-induced experimental autoimmune encephalomyelitis. In contrast, isolated neuronal or axonal protection without clinical benefit was achieved under monotherapy with erythropoietin or methylprednisolone, respectively.

Animals↗
PubMed2004

A novel role for an established player: anemia drug erythropoietin for the treatment of cerebral hypoxia/ischemia.

Erythropoietin, a hematopoietic growth-factor possessing manifold, potent neuroprotective properties, after multiple testing in cell culture and animal studies now gradually finds its way into clinical neuroscience. The first time this took place was in 1998 with a pilot study in stroke patients, the "Göttingen EPO-Stroke-Trial". This study was able to demonstrate that EPO is perfectly well tolerated and safe with this indication. Furthermore, the EPO-treated patients showed a significantly better outcome regarding their clinical progress as well as regarding the infarct size as observed by MRI, when compared to the placebo treated patients. At the moment a multicenter study is being carried out in Germany.

Anemia↗
PubMed2004

Erythropoietin: novel approaches to neuroprotection in human brain disease.

With the increased life expectancy in western industrialized countries, the incidence and prevalence of brain diseases dramatically increased. Stroke and a wide spectrum of neuropsychiatric illnesses such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, traumatic head injury, and schizophrenia all lead to severe disability. However, targeted effective therapies for treatment of these diseases are lacking. Even more frustrating is the fact that we do not yet clearly understand the basic mechanisms underlying the disease processes in these conditions. We propose a hypothesis of loss of neuronal function via a final common deleterious pathway in this clinically very heterogeneous disease group. This review presents a novel neuroprotective concept for treatment of brain disease: Erythropoietin (EPO). EPO is a natural body-own-protein hormone that has been used for treatment of anemia for more than a decade. The neuroprotective approach using EPO in brain disease represents a totally new frontier. The "Göttingen EPO-stroke trial" represents the first effective use in man of a neuroprotective therapy in an acute brain disease while the experimental EPO therapy to combat cognitive decline in patients with schizophrenia will be introduced as an example of a neuroprotective strategy for a chronic brain disease.

Animals↗