Alberto Gaiti

EFFECT OF EXERCISE TRAINING, SELENIUM AND VITAMIN E ON SOME FREE RADICAL SCAVENGERS IN HORSES (EQUUS CABALLUS)

Physical exercise increases both tissue needs for oxygen and cellular respiration and causes an overproduction of free radicals. When free radical generation exceeds the cells antioxidant capacity tissue-damage develops due to oxidative stress. Therefore, it appears important to increase the scavenger ability of the tissues. Controlled training and dietary supplements may provide ways of doing this. As a model, we used 3-year-old racehorses (Equus caballus) which underwent a series of different physical exercise trials before and after 70 days of daily training and dietary supplements (vitamin E and selenium). The above treatments were able to increase both red blood cell resistance to the peroxidative stress induced in vitro and the glutathione peroxidase activity in lymphocytes. Moreover, they were also able to decrease malondialdehyde (MDA) concentration in the plasma as well as vitamin E consumption and the mobilisation of low molecular weight antioxidants (total peroxyl-radical trapping) following the physical exercise trials. The results obtained indicated that the training and diet supplements we used were able to significantly increase horse antioxidant defences in both the extracellular fluids and blood cells of our horses, thus decreasing peroxidative phenomena following physical exercise.

Physical exercise, oxidative stress and muscle damage in racehorses

Since it has been suggested that lipid peroxidation following free radical overproduction may be one of the causes of physical exercise-induced myopathies and hemolysis in horses, we looked for the possible relationships between these phenomena and muscle fiber damage. We use a homogeneous group of Maremmana stallions which, after a 3-month training period, underwent a series of physical exercises of increasing intensity. We determined the contents of malondialdehyde (MDA), one of the main lipid peroxidation end-products, and glutathione the substrate of one of the most important free radical scavenger enzymes. We also measured creatine phosphokinase and serum lactate dehydrogenase isoenzyme activities whose modification may be indicative of muscle fiber damage. The results obtained indicated that the physical exercise we adopted was able to modify both MDA and glutathione contents in blood. However, its effect on some LDH isoenzyme activities suggested possible damage to tissues other than muscle.

Acute Phase Reactant α1antichymotrypsin Is Increased in Cerebrospinal Fluid and Serum of Patients with Probable Alzheimer Disease

Levels of α1-antichymotrypsin (α1-ACT) in cerebrospinal fluid (CSF) and serum from patients with probable Alzheimer disease (AD) of both early (e-AD) and late (1-AD) onset assessed by a competitive enzyme-linked immunosorbent assay were higher than those found in controls or in patients with vascular dementia (VD). A negative correlation between CSF levels of α1-ACT and the stage of the disease was present in patients with both e-AD and 1-AD. No difference in α1-macroglobulin levels in CSF and serum from patients with e-AD, 1-AD, VD, and nondemented controls was found. Serum concentrations of α1-antitrypsin from 1-AD subjects were within the normal range. Thus, increased levels of α1-ACT in CSF and serum were specifically associated with AD, and the detection of this serpin in CSF may be useful in monitoring the progression of the disease.

Blood-brain-barrier in a geriatric population : barrier function in degenerative and vascular dementias

ABSTRACT Albumin and IgG were determined in serum and cerebrospinal fluid (CSF) of patients with early‐onset Alzheimers disease (AD, n. 13), senile dementia of Alzheimer type (SDAT, n. 33), vascular dementia divided into multi‐infarct (MID, n. 9) and probable vascular (PVD, n. 11) dementia. Albumin and IgG ratio and IgG index were calculated. CSF albumin and albumin ratio were significantly higher in MID patients indicating an increased BBB permeability. IgG ratio and IgG index did not show any significant difference among groups. These results do not provide evidence for BBB damage in AD/SDAT, while in MID the increase of CSF albumin and albumin ratio is suggestive of BBB dysfunction.

The synthesis in vivo of choline and ethanolamine phosphoglycerides in different brain areas during aging.

The biosynthesis of choline and ethanolamine phosphoglycerides was tested in vivo in different brain areas of the rat during aging. Mixtures of [2−3H] glycerol and [Me-14C] choline or [2-3H] glycerol and [2-14H] ethanolamine were injected into lateral ventricle of the brain as lipid precursors and their incorporation into corresponding phospholipid was examined. A significant decrease of synthesis of both phosphoglycerides takes place in cerebral cortex and in the striatum, and is already apparent at 9 months of age with no further decrease or change therafter. No significant change takes place in the cerebellum. The unchanged absorption of injected water-soluble precursors, together with the lack of any significant change of phospholipid/protein ratio in all examined brain areas, suggests that the incorporation of both glycerol and nitrogen bases are affected by aging.

Phospholipid metabolism in neuronal and glial cells during aging

The incorporation of cytidine-containing precursors (CDP-Cho and CDP-Etn) into the main phospholipid classes of cellular fractions enriched in neurons and glial cells from whole rat brains of different ages was examined. The rate of synthesis of choline phosphoglycerides in neuronal homogenates significantly decreased with age up to 18 months; after this time no additional decrease was found. The decrease of CDP-Etn incorporation in neurons was found to be less significantly affected by age up to 18 months, but the enzymic activity decreased after 18 months of age. No changes were found in the corresponding glial activity at any age. Biochemical phenomena that occur in 18-month-old rat brain (aged animals) were compared with phenomena occurring in 2-month-old rat brain (adult animals). No significant variations of lipid composition were found in neurons from either 18-month-old or 2-month-old rat brain. These results, together with some kinetic parameters, suggest that ethanolamine and choline phosphotransferases are affected differently by aging.

Platelet MAO-B activity as a marker of behavioural characteristics in dementia disorders

Both low and high platelet MAO-B (pMAO-B) activity is considered an indicator of increased vulnerability in psychopathology. How the activity of this peripheral enzyme can be linked with the sophisticated functions of the central nervous system (CNS) is not clear; in man, evidence exists that the genetic mechanisms determining the size or capacity of the central serotonin system are common to platelet and brain MAO. In the present study pMAO- B activity was evaluated in demented patients suffering from early- onset Alzheimer’s disease (AD), late- onset Alzheimer’s disease (SDAT), vascular dementia (VD), and controls. In these dementia categories, the relationship between pMAO- B activity and clinical features, and between pMAO- B activity and cerebrospinal fluid (CSF) monoamine metabolites (3-methoxy-4-hydroxyphenyl-glycol, MHPG; 5-hydroxy-in-doleacetic acid, 5-HIAA; homovanillic acid, HVA) was also investigated. pMAO-B activity was significantly higher in SDAT patients, compared to controls and AD. Age, as covariate, failed to show any significant effect, and no association was found between pMAO-B activity and CSF monoamine metabolites. The correlation analysis between pMAO-B and neuropsychological scores showed a highly significant positive relationship with GBS- emotional impairment (N=40, r=0.72, p<0.01 in the SDAT group. This result suggests the importance of platelet MAO- B activity as biological marker also in old- age dementias, namely senile dementia of Alzheimer type, where the increased activity of this enzyme might constitute a marker for vulnerability toward behavioural disturbance, i.e., emotional deterioration. (Aging Clin. Exp. Res. 6: 201–207, 1994)

Plasma protein changes in horse after prolonged physical exercise: a proteomic study.

Physical exercise induces various stress responses and metabolic adaptations that have not yet been completely elucidated. Novel biomarkers are needed in sport veterinary medicine to monitor training levels and to detect subclinical conditions that can develop into exercise-related diseases. In this study, protein modifications in horse plasma induced by prolonged, aerobic physical exercise were investigated by using a proteomic approach based on 2-DE and combined mass spectrometry procedures. Thirty-eight protein spots, associated with expression products of 13 genes, showed significant quantitative changes; spots identified as membrane Cu amine oxidase, α-1 antitrypsin, α-1 antitrypsin-related protein, caeruloplasmin, α-2 macroglobulin and complement factor C4 were augmented in relative abundance after the race, while haptoglobin β chain, apolipoprotein A-I, transthyretin, retinol binding protein 4, fibrinogen γ chain, complement factor B and albumin fragments were reduced. These results indicate that prolonged physical exercise affects plasma proteins involved in pathways related to inflammation, coagulation, immune modulation, oxidant/antioxidant activity and cellular and vascular damage, with consequent effects on whole horse metabolism.

Gambling on putative biomarkers of osteoarthritis and osteochondrosis by equine synovial fluid proteomics.

Osteoarthritis (OA) and osteochondrosis (OC) are two of the main challenges in orthopedics, whose definitive diagnosis is usually based on radiographic/arthroscopic evidences. Their early diagnosis should allow preventive or timely therapeutic actions, which are generally precluded from the poor relationships occurring between symptomatologic and radiographic evidences. These limitations should be overcome by improving the knowledge on articular tissue metabolism and on molecular factors regulating its normal homeostasis, also identifying novel OA and OC biomarkers suitable for their earlier diagnoses, whenever clinical/pathological inflammatory scenarios between these joint diseases seem somewhat related. To identify proteins involved in their aetiology and progression, we undertook a differential proteomic analysis of equine synovial fluid (SF), which compared the protein pattern of OA or OC patients with that of healthy individuals. Deregulated proteins in OA and OC included components related to inflammatory state, coagulation pathways, oxidative stress and matrix damage, which were suggestive of pathological alterations in articular homeostasis, plasma-SF exchange, joint nutritional status and vessel permeability. Some proteins seemed commonly deregulated in both pathologies indicating that, regardless of the stimulus, common pathways are affected and/or the animal joint uses the same molecular mechanisms to restore its homeostasis. On the other hand, the increased number of deregulated proteins observed in OA with respect to OC, together with their nature, confirmed the high inflammatory character of this disease. Some deregulated proteins in OA found a verification by analyzing the SF of injured arthritic joints following autologous conditioned serum treatment, an emergent therapy that provides positive results for both human and equine OA. Being the horse involved in occupational/sporting activities and considered as an excellent animal model for human joint diseases, our data provide suggestive information for tentative biomedical extrapolations, allowing to overcome the limitations in joint size and workload that are typical of other small animal models.

Enzymic synthesis of plasmalogen and O-alkyl glycerolipid by base-exchange reaction in the rat brain

It has been demonstrated recently that a Ca2+-dependent bassexchange system occurs in subcellular fractions of brain which can convert in vitro, at the expenses of endogenous phospholipid, labelled ethanolamine, serine, choline or other nitrogenous bases into EPG, SPG, CPG or other lipids [l-3]. Membranes from the endoplasmic reticulum of chick, rat and rabbit brains were found to possess the highest rate of incorporation, and the requirement for Ca2+ appeared to be absolute. The reaction, which takes place also in non-nervous tissue (see [2]), is regarded as an exchange process, not requiring energy, between the bound-base of the exchanging membrane phospholipid and the free base [2,3], and cannot be compared for several reasons with any of the known pathways of lipid synthesis. On studying this system we obtained evidence that the greater part of the incorporated ethanolamine or serine (about 85%) was confined to labelled diacylGPE or diacyl-GPS, respectively; the remainder of the radioactivity was not accounted for. The experiments described here were aimed at examining whether alkenylacyl-GPE and alkenylacyl-GPS could also be produced by similar mechanisms. It is shown that the microsomal fraction from rat brain converts by base-exchange labelled L-serine or ethanolamine into the plasmalogen derivatives [l-3], and the reaction restem are similar to those described for the synthesis of the diacyl derivative [l-3], and the reaction requires Ca2+ as the only factor to obtain the exchange.