Aquaporins and glia

Glial cells coordinate the differentiation, metabolism, and excitability of neurons; they modulate synaptic transmission and integrate signals emanating from neurons and other glial cells. Several evidences underlying the relation between these pathways and the regulatory mechanisms of ion concentration, supporting the role of Aquaporins (AQPs) in these processes. The goal of this review is to summarize the localization of different isoforms of AQPs in relation to glial cells both in central and peripheral nervous system, underlying AQP involvement in physiological and in pathophysiological conditions such as brain edema, glioma and epilepsy.

Use of NaCl saline hydration and N-Acetyl Cysteine to prevent contrast induced nephropathy in different populations of patients at high and low risk undergoing coronary artery angiography

AIM

Contrast-induced nephropathy (CIN) is most commonly defined as acute renal failure occurring within 48-72 h of exposure to intravascular radiographic contrast medium that is not attributable to other causes. In international literature a 25% increase in serum creatinine levels or an increase in absolute values of 0.5 mg/dL from baseline has been suggested to define CIN. The reported incidence of CIN varies widely, ranging from 2% to 50%. This variability results from differences in the presence or absence of risk factors. With a retrospective analysis authors evaluated the use of NaCl saline hydration and N-acetyl cysteine (NAC) to prevent CIN in different populations of patients at high and low risk undergoing coronary artery angiography.

METHODS

From January 2007 to December 2008, 597 patients underwent coronary artery angiography with a low osmolarity contrast agent. Nephrotoxic drugs such as diuretics, metformin, ACE-I and ARBs were stopped at least 24 h before the procedure. The population was divided into two groups: group A (high risk 342 patients, 57.2%) identified for the presence of at least one risk factor such as diabetes, age >65 years, baseline creatinine >1.4 mg/dL and group B (low risk 255 patients, 42.8%) for the absence of any of the risk mentioned above. Only group A was treated with a saline hydration (1 mL/kg/h) plus NAC 600 mg 12 h before and 12 h after the procedure.

RESULTS

The overall incidence of CIN was 6.7% (40 patients). In particular, the incidence of CIN was 4.4% (15 patients) in the group A and 9.8% (25 patients) in the group B respectively (P=0.017). Interestingly, the Contrast Index (volume administrated/theoretical maximum volume) was significantly lower in group B (P<0.005). In the multivariate analysis, including risk factors such as age, diabetes, hypertension, hypercholesterol-mia, current smoke, baseline creatinine level, Contrast Index and hydration, the last variable was the only one inversely correlated independently with the incidence of CIN (P=0.001).

CONCLUSIONS

The hydration with saline and NAC is an effective and low-cost tool in preventing CIN in patients undergoing coronary artery angiography and, according to the current guidelines, should be used in all high-risk patients. Present results show that even in patients at low risk for CIN, hydration could be useful: in fact, despite the Contrast Index was significantly lower in this population, the incidence of CIN was greater, thus suggesting a potential role for hydration also in the low-risk population.

Regression of diabetic complications by islet transplantation in the rat

AIMS/HYPOTHESIS

Type 1 diabetes is a chronic disease leading to complications such as peripheral neuropathies, nephropathy and cardiovascular disease. Pancreatic islet transplantation is being extensively investigated for blood glucose control in animals and in human type 1 diabetic patients, but the question of whether it can reverse long-term diabetic complications has not been fully explored. We investigated the effects of islet transplantation on diabetic complications in a rat model of streptozotocin-induced diabetes.

METHODS

Three groups of rats were used: healthy controls, diabetic and diabetic rats transplanted with microencapsulated islets at 2 months after diabetes induction, when neuropathy was detectable by a decrease in tail nerve conduction velocity (NCV) and impaired nociceptive thresholds. Blood glucose levels and body weight were measured weekly. The variables considered were: thermal (hot plate test) and mechanical sensitivity (Randal-Selitto paw withdrawal test), NCV and Na+, K+-ATPase activity in the sciatic nerve. At the end of the experiments hearts were removed for morphometric determination and myocyte number, and kidneys removed for histological examination.

RESULTS

Islet transplantation in diabetic rats induced normoglycaemia in a few days, accompanied by a rapid rise in body weight and amelioration of impaired nociceptive thresholds, as well as normalisation of NCV and Na(+), K(+)-ATPase, which were both about 25% below normal in diabetic rats. Myocyte loss was reduced (-34%) by islet transplantation and the observed mild kidney damage of diabetic rats was prevented.

CONCLUSIONS/INTERPRETATION

Besides controlling glycaemia, transplantation of microencapsulated pancreatic islets induced almost complete regression of neuropathy and prevented cardiovascular alterations.

Effects of olmesartan and enalapril at low or high doses on cardiac, renal and vascular interstitial matrix in spontaneously hypertensive rats

We have evaluated the effects of different doses of an angiotensin-converting enzyme (ACE) inhibitor, enalapril (ENA) and of an angiotensin II type 1 receptor blocker olmesartan (OLM), on extracellular matrix of the heart, kidney, aorta and mesenteric artery of spontaneously hypertensive rats (SHR). Forty SHR and eight Wistar-Kyoto controls (WKY) were included in the study. Eight SHR were treated with high-dose OLM 15 mg/kg per day, eight with high-dose ENA 25 mg/kg per day, eight with low-dose OLM 1 mg/kg per day and eight with low-dose ENA (2 mg/kg per day). Eight SHR and eight WKY were kept untreated as controls. Treatment was from age 4 to 12 weeks. Systolic blood pressure (SBP) was measured non-invasively every week. The left ventricular weight to body weight (RLVM) was measured, and the cardiac, aortic and glomerular interstitial collagen content was evaluated using Sirius red staining and image analysis. Mesenteric small arteries were dissected and mounted on a micromyograph, and the media:lumen ratio (M/L) was calculated. Collagen subtypes were evaluated by polarized light microscopy. The SHR treated with high-dose OLM or ENA showed a normalization of SBP. The RLVM was significantly increased in untreated SHR compared with untreated WKY, whereas significantly lower values were observed in the groups of SHR treated with high-dose OLM or ENA. A significant increase in cardiac and glomerular collagen content was observed in untreated SHR. Both high- or low-dose OLM and ENA normalized collagen content in the heart and the kidney. Both high-dose OLM and high-dose ENA normalized M/L ratio; however, OLM proved to be more effective than ENA in normalizing collagen pattern. In fact, aortic collagen content was normalized by both high-dose and low-dose OLM, but only by high-dose ENA. In conclusion, both OLM and ENA were significantly and equally effective in the prevention of cardiac and renal damage in SHR, whereas OLM was more effective than ENA in terms of effects on vascular extracellular matrix.

Aspects of the bionomics of Phlebotomus sergenti sandflies from an endemic area of anthroponotic cutaneous leishmaniasis in Aleppo Governorate, Syria

Aspects of the bionomics of phlebotomine sandflies (Diptera: Psychodidae) were studied from June to November 2005 in three foci of anthroponotic cutaneous leishmaniasis (ACL) in Aleppo Governorate, Syria, where the agent Leishmania tropica (Wright) (Kinetoplastida: Trypanosomatidae) is transmitted by Phlebotomus sergenti Parrot. Syria has been designated by the World Health Organization as one of four countries in the Old World where cutaneous leishmaniasis is hyperendemic, but little is known about the biology of local vector populations. Standard collections by sticky traps showed two peaks in density, in June and late August. In total, 1840 sandflies were caught, comprising five species: Phlebotomus papatasi (Scopoli) (68.0%); P. sergenti (25.4%); Sergentomyia minuta (Rondani) (6.4%); Phlebotomus tobbi Adler & Theodor (0.1%), and Phlebotomus mascittii canaaniticus Adler & Theodor (0.1%). Similar numbers of P. sergenti were caught indoors (246 specimens) and outdoors (222), whereas P. papatasi was significantly more abundant indoors (1096 specimens) than outdoors (156) (chi(2) = 241, P < 0.01). In total, 212 blood-fed females were tested for host blood determination, of which 176 (83.0%) reacted with anti-species reagent. Results from 20 P. sergenti suggest that this species is an opportunistic feeder, imbibing human, ovine, avian, bovine and feline blood, although more bloodmeals were taken from humans and cattle than expected in relation to the relative proportions of potential hosts present (the forage ratio, FR). The bionomics of P. sergenti are discussed in relation to the inefficacy of control campaigns based on indoor spraying with residual insecticides that have been implemented by the Syrian Ministry of Health to control the epidemics of ACL in the Aleppo Governorate.

Development and Preliminary Experience with an Ease of Extractability Rating System for Prescription Opioids

One important factor in the abuse potential of an opioid product is the ease with which active drug can be extracted. There are currently no standards for testing or reporting extractability. This article describes the development of an Extractability Rating System for use by the pharmaceutical industry and regulators. Despite several limitations, this effort serves as a call for standardized testing and reporting so that products can be accurately rated, and should help establish goals for drug developers who wish to develop "abuse-resistant" opioid products.

Red wine polyphenols prevent cyclosporine-induced nephrotoxicity at the level of the intrinsic apoptotic pathway

Flavonoids, polyphenol derivatives of plant origin, possess a broad range of pharmacological properties. A number of studies have found both pro/anti-apoptotic effects for many of these compounds. For these reasons we investigated whether Provinols flavonoids obtained from red wine, have anti-apoptotic properties. The investigations have been carried out in rats treated with Cyclosporine A (CsA). In particular, four groups of rats have been treated for 21 days with either olive oil (control group), with CsA, with Provinols, or with CsA and Provinols simultaneously. Oxidative stress, systolic blood pressure, body weight, biochemical parameters and different markers of pro/anti-apoptotic pathway were measured. CsA produced an increase of systolic blood pressure, a decrease in body weight, serum creatinine levels, urinary total protein concentration and creatinine clearance. Moreover, CsA induced renal alterations and the translocation of Bax and cytochrome c from cytoplasm to mitochondria and vice versa. These changes activated the caspase cascade pathway, that leads to morphological and biochemical features of apoptosis. Provinols restored morphological and biochemical alterations and prevented nephrotoxicity. In conclusion, this study may augment our current understanding of the controversial pro-/anti-apoptotic properties of flavonoids and their molecular mechanisms.

Morphometric changes induced by amino acid supplementation in skeletal and cardiac muscles of old mice

Aging is associated with progressive structural disorganization of muscular and cardiac fibers, decreasing functional capacity, and increased rates of disease and death. Aging is also characterized by disturbances in protein synthesis with impaired cellular organelle functions, particularly in the mitochondria. The availability of amino acids is a key factor for the overall metabolism of mammals and exogenous supplements of amino acid mixtures (AAm) could be a valid therapeutic strategy to improve quality of life, avoiding malnutrition and muscle wasting in the elderly. We investigated the morphoquantitative effects of long-term AAm supplementation on the mitochondria and sarcomeres (by electron microscope) and on collagen matrix deposition (by histologic techniques) in both skeletal and cardiac muscles of young and aged mice. Our data showed that old animals have fewer mitochondria and massive fibrosis in both muscles. Long-term AAm supplementation increased the number and volume of mitochondria and sarcomeres and decreased fibrosis in both skeletal muscle and hearts in old rats. These findings indicate that AAm restored muscular morphologic parameters and probably improved the mechanical performance of these organs.

Aluminium exposure induces Alzheimer's disease-like histopathological alterations in mouse brain

Aluminium (Al) is a neurotoxic metal and Al exposure may be a factor in the aetiology of various neurodegenerative diseases such as Alzheimer's disease (AD). The major pathohistological findings in the AD brain are the presence of neuritic plaques containing beta-amyloid (Abeta) which may interfere with neuronal communication. Moreover, it has been observed that GRP78, a stress-response protein induced by conditions that adversely affect endoplasmic reticulum (ER) function, is reduced in the brain of AD patients. In this study, we investigated the correlation between the expression of Abeta and GRP78 in the brain cortex of mice chronically treated with aluminium sulphate. Chronic exposure over 12 months to aluminium sulphate in drinking water resulted in deposition of Abeta similar to that seen in congophilic amyloid angiopathy (CAA) in humans and a reduction in neuronal expression of GRP78 similar to what has previously been observed in Alzheimer's disease. So, we hypothesise that chronic Al administration is responsible for oxidative cell damage that interferes with ER functions inducing Abeta accumulation and neurodegenerative damage.

Effects of aluminium sulphate in the mouse liver: similarities to the aging process

Aluminium (Al) is a ubiquitous metal that is potentially toxic to the brain. Its effects on other fundamental organs are not completely understood. This morphological in vivo study sought to compare sublethal hepatotoxic changes and Al deposition in adult mice that orally ingested Al sulphate daily for 10 months, in age matched control mice that drank tap water and in senescent mice (24 months old). Livers were examined for collagen deposition using Sirius red and Masson, for iron accumulation using Perls' stain. Light, electron microscopy and morphometry were used to assess fibrosis and vascular changes. Scanning transmission electron microscopy and EDX microanalysis were used to detect in situ elemental Al. Iron deposition, transferrin receptor expression were significantly altered following Al exposure and in the aged liver but were unaffected in age matched control mice. In Al treated mice as in senescent mice, endothelial thickness was increased and porosity was decreased like perisinusoidal actin. Furthermore, Al stimulated the deposition of collagen and laminin, mainly in acinar zones 1 and 3. Pseudocapillarization and periportal laminin in senescent mice were similar to Al treated adult liver. In conclusion, prolonged Al sulphate intake accelerates features of senescence in the adult mice liver.

Atherosclerosis and oxidative stress

This review focuses on the morphological features of atherosclerosis and the involvement of oxidative stress in the initiation and progression of this disease. There is now consensus that atherosclerosis represents a state of heightened oxidative stress characterized by lipid and protein in the vascular wall. Reactive oxygen species (ROS) are key mediators of signaling pathways that underlie vascular inflammation in atherogenesis, starting from the initiation of fatty streak development, through lesion progression, to ultimate plaque rupture. Plaque rupture and thrombosis result in the acute clinical complications of myocardial infarction and stroke. Many data support the notion that ROS released from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, myeloperoxidase (MPO), xanthine oxidase (XO), lipoxygenase (LO), nitric oxide synthase (NOS) and enhanced ROS production from dysfunctional mitochondrial respiratory chain, indeed, have a causatory role in atherosclerosis and other vascular diseases. Moreover, oxidative modifications in the arterial wall can contribute to the arteriosclerosis when the balance between oxidants and antioxidants shifts in favour of the former. Therefore, it is important to consider sources of oxidants in the context of available antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase and transferases thiol-disulfide oxidoreductases and peroxiredoxins. Here, we review also the mechanisms in which they are involved in order to accelerate the pace of the discovery and facilitate development of novel therapeutic approaches.

Effects of acute caffeine administration on NOS and Bax/Bcl2 expression in the myocardium of rat

Caffeine is the most frequently ingested neuroactive drug in the world and it is largely used to delay fatigue and improve physical activity. Caffeine can modulate NO synthesis in cells and may influence muscular function by modifying the cellular cycle life-death. There is little data concerning the relationship between caffeine in the heart, NOS expression and apoptosis and no data regarding the acute effect of high doses of caffeine in the in vivo myocardium. We therefore studied hemodynamic NOS and Bax/Bcl2 expression in the rat myocardium after a single cafffeine administration. Thirty-two male rats were divided into six groups: the first was iv-injected with caffeine (16 mg/kg), the second with caffeine + L-NAME (30 mg/kg), the third with caffeine + L-arg (0.5 g/kg), the fourth with caffeine + L-NAME + L-arg and finally the fifth with saline. Mean arterial blood pressure (MAP) was monitored for 30 min, then the animals were killed. The sixth group was injected with caffeine and killed after 2 h. The hearts were isolated and processed by immunohistochemistry. We found that caffeine increased MAP temporarily while caffeine + L-NAME increased it for a longer period. In the control myocardium, all NOS isoforms were expressed. The Bcl2 were strongly expressed inside the perinuclear cytoplasm whereas Bax was very faintly detectable in the peripheral cytoplasm. In caffeine and caffeine + L-NAME treated animals, NOS expression disappeared. Bax and Bcl2 expression did not vary. The l-arg administration reversed these caffeine and L-NAME effects on NOS expression. Two hours after caffeine, NOS expression increased and Bax and Bcl2 expression did not vary, although Bcl2 was mainly expressed in the peripheral cytoplasm. We conclude that improved caffeine-induced physical performance could also be related to caffeine's ability to interfere with endogenous myocardial NO synthesis. Furthermore, we suggest that myocardial cell plays an effective anti-apoptotic role against acute caffeine administration.

Chest wall kinematics during cough in healthy subjects

AIM

The study of kinematics of the chest wall (CW) could allow us to define the relative deflationary contribution of its compartments during fits of coughing. We hypothesized that if forces applied to the lung apposed rib cage are not commensurate with those applied to the abdomen-apposed rib cage, cough could result in rib cage distortion.

METHODS

In 12 (five women) healthy subjects we evaluated the volumes of CW (Vcw) and its compartments: the lung apposed rib cage, the abdomen apposed rib cage and the abdomen, by optoelectronic plethysmography. The loop of volume of the lung apposed rib cage/volume of the abdomen apposed rib cage allowed the calculation of mean rib cage distortion, resulting in a dimensionless number which, when multiplied by 100, gives percentage distortion. Each subject performed voluntary single and prolonged coughing efforts at functional residual capacity (FRC) and after maximal inspiration (max). The normal level of mean distortion was set at <0.5%.

RESULTS

The three compartments contributed to reducing end-expiratory Vcw during cough at FRC and prolonged maximum cough, with the latter resulting in the greatest CW deflation. Mean rib cage distortion did not differ between men and women (P > 0.1), but tended to significantly increase from single to prolonged Cough Max (1.3% +/- 1.0 vs. 2.3% +/- 1.6, respectively; P = 0.06).

CONCLUSION

Rib cage distortion may ensue during coughing, probably as a result of uneven distribution of forces applied to the rib cage.

Altered immunolocalization of heat-shock proteins in human peri-implant gingiva

It has been suggested that heat-shock proteins (HSPs) might be involved in autoimmune disease mechanisms in humans, considering the high degree of sequence homology between bacterial and human HSPs. Several authors have postulated that HSPs might be involved in periodontal disease processes, but not specifically in peri-implantitis. Consequently, using immunohistochemical techniques, we studied the distribution of HSP25, HSP32, HSP60 and HSP72 in three groups of patients: (1) subjects with natural teeth (healthy periodontal tissue), (2) subjects with normal peri-implant mucosa and (3) subjects with clinically evident peri-implantitis. The immunolabelling for HSP25 and HSP60 was increased in the peri-implantitis group HSP32 immunolabelling slightly decreased in peri-implant and peri-implantitis gingiva. Labelling for HSP72 was undetectable in all three groups. In conclusion, we observed in peri-implantitis a clearly enhanced immunolabelling of two specific HSPs, HSP25 and HSP60, restricted to gingival epithelium and this could indicate a signal of local altered homeostasis.

Testosterone derivatives are neuroprotective agents in experimental diabetic neuropathy

In this study we have assessed the effect of testosterone (T), dihydrotestosterone (DHT) and 5alphaandrostan-3alpha, 17beta-diol (3alpha-diol) therapies on diabetic neuropathy. Diabetes was induced in adult male rats by the injection of streptozotocin and resulted in decreased T and increased 3alpha-diol levels in plasma and in decreased levels of pregnenolone and DHT in the sciatic nerve. Moreover, a reduced expression of the enzyme converting Tinto DHT (i.e., the 5alpha-reductase) also occurs at the level of sciatic nerve, suggesting that the decrease of DHT levels could be due to an impairment of this enzyme. Chronic treatment for 1 month with DHT or 3alpha-diol increased tail nerve conduction velocity and partially counteracted the increase of thermal threshold induced by diabetes. Treatment with DHT increased tibial Na(+),K(+)-ATPase activity and the expression of myelin protein P0 in the sciatic nerve.DHT, 3alpha-diol and T reversed the reduction of intra-epidermal nerve fiber density induced by diabetes. These observations indicate that T metabolites can reverse behavioral, neurophysiological, morphological and biochemical alterations induced by peripheral diabetic neuropathy.

Professional clinical bleaching with Pola Office: 6-month clinical results with spectrophotometric analysis

AIM

The aim of the study was to evaluate the efficacy of the professional bleaching treatment with Pola Office (SDI): the shade, chroma and value parameters of the anterior upper elements were analysed.

METHODS

At the Prosthetic Unit of the Modena and Reggio Emilia University, 10 patients were selected. All patients underwent oral hygiene treatment and spectrophotometric analysis (Spectro-Shade) of the 6 front elements: the variables L (value), c (chroma), and h (shade) were examined in the cervical, mesial and incisal sections. Spectrophotometric analysis was repeated 6 months after initial bleaching. The patients were asked to report the degree of sensitivity after 3, 6, 12 and 24 h and after 3, 6, 7, and 10 days.

RESULTS

The value (L) of the treated elements increases after bleaching, the chroma parameter (c) showed lower values than those prior to treatment (except for the first patient); this means a shift towards a lower degree of saturation. The course of the shade parameter is uniform and constant for all patients, with a shift towards yellow chroma values. Postoperative sensitivity was confined to the first 3 h after treatment, after which it showed a steady decrease over 24 h.

CONCLUSIONS

Esthetic results obtained using the Pola Office bleaching procedure were visibly significant; confirmed by colorimeter analysis. The harmony between chroma, shade and value remained 6 months after the bleaching treatment; the sensitivity is particularly high in the first hour, however after 24 h sensitivity is greatly reduced.

AM404 decreases Fos-immunoreactivity in the spinal cord in a model of inflammatory pain

Cannabinoids, such as anandamide, are involved in pain transmission. We evaluated the effects of AM404 (N-(4-hydroxyphenyl)-5Z,8Z,11Z,14Z-eicosatetraenamide), an anandamide reuptake inhibitor, monitoring the expression of c-fos, a marker of activated neurons and the pain-related behaviours using formalin test. The study was carried out in an experimental model of inflammatory pain made by a single injection of formalin in rat hind paws. Formalin test showed that the antinociceptive effect of AM404 was evident in phase I. We found that Fos-positive neurons in dorsal superficial and deep laminae of the lumbar spinal cord increased in formalin-injected animals and that AM404 significantly reduced Fos induction. Co-administration of cannabinoid CB(1) receptor antagonist (AM251), cannabinoid CB(2) receptor antagonist (AM630) and transient receptor potential vanilloid type 1 (TRPV-1) antagonist (capsazepine), attenuate the inhibitory effect of AM404 and this effect was higher using cannabinoid CB(2) and vanilloid TRPV-1 receptor antagonists. These results suggest that AM404 could be a useful drug to reduce inflammatory pain in our experimental model and that cannabinoid CB(2) receptor and vanilloid TRPV-1 receptor, and to a lesser extent, the cannabinoid CB(1) receptor are involved.

Atherosclerosis and the protective role played by different proteins in apolipoprotein E-deficient mice

The aim of the present study was to analyze the early events in atherogenesis and the role of pro- or anti-atherosclerotic proteins in the development of atherosclerotic lesions. We used apolipoprotein E-deficient (E(0)) mice that spontaneously develop hypercholesterolemia and atherosclerotic lesions in the aorta in a time-dependent manner. Aortas of mice aged 6, 8, 10 and 12 weeks were examined to determine histopathological changes. In mice aged 8-12 weeks, developing atherosclerotic lesions were present in different regions of the aortas. These lesions protruded into the lumen of the vessel and showed lipid deposits, lipid-filled macrophages and extensive accumulation of collagen and elastic fibers throughout the entire arterial wall. A parallel immunohistochemical study included analysis of three proteins known to be involved in atherosclerosis, i.e. inducible nitric oxide synthase (iNOS, NOS2), vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP2). Increased immunolabelling of iNOS and VEGF accompanied atherosclerosis development in E(0) mice aged 8, 10 and 12 weeks. On the contrary, immunolabelling for MMP2 was negative in E(0) mice aged 10 and 12 weeks. Our results indicate morphological alterations in the Tunica intima and Tunica media of atherosclerotic aortas and possible protective roles for iNOS and VEGF proteins against atherosclerosis development. These data may be relevant for developing therapeutic strategies for atherosclerosis development.

Acute caffeine administration decreased NOS and Bcl2 expression in rat skeletal muscles

Caffeine (Caf) is largely used to delay fatigue, improving physical activity. However, its role remains elusive, and there are no hemodynamic or immunohistochemical data regarding its effects on skeletal muscle. We studied the hemodynamic and NOS expression of Bax/Bcl2 in skeletal muscle after single Caf administration. Thirty-two male rats were divided into six groups: the first was iv-injected with Caf (16mg/kg), the second with Caf+L-NAME, the third with Caf+L-arg, the fourth with Caf+L-NAME+L-arg, fifth with saline. Mean arterial blood pressure (MAP) was monitored for 30', then the animals were killed. The sixth group was injected with Caf and killed after 2h. The quadriceps were isolated and processed by immunohistochemistry. We found that Caf increased MAP temporarily, while Caf+L-NAME increased it for a longer period. In untreated muscle, all NOS isoforms was expressed with different intensity and localisation, and Bcl2 was strongly expressed among the myofibrils. In Caf and Caf+L-NAME treated animals, NOS expression was lost; Bcl2 expression decreased among myofibrils but increased inside the subsarcolemma. The L-arg administration reversed these Caf and L-NAME effects. Two hours after Caf, NOS expression increased. We concluded that improved physical performance could be related to Caf's ability to interfere with the endogenous muscular synthesis of NO.

Progesterone and its derivatives are neuroprotective agents in experimental diabetic neuropathy: a multimodal analysis

One important complication of diabetes is damage to the peripheral nervous system. However, in spite of the number of studies on human and experimental diabetic neuropathy, the current therapeutic arsenal is meagre. Consequently, the search for substances to protect the nervous system from the degenerative effects of diabetes has high priority in biomedical research. Neuroactive steroids might be interesting since they have been recently identified as promising neuroprotective agents in several models of neurodegeneration. We have assessed whether chronic treatment with progesterone (P), dihydroprogesterone (DHP) or tetrahydroprogesterone (THP) had neuroprotective effects against streptozotocin (STZ)-induced diabetic neuropathy at the neurophysiological, functional, biochemical and neuropathological levels. Using gas chromatography coupled to mass-spectrometry, we found that three months of diabetes markedly lowered P plasma levels in male rats, and chronic treatment with P restored them, with protective effects on peripheral nerves. In the model of STZ-induced of diabetic neuropathy, chronic treatment for 1 month with P, or with its derivatives, DHP and THP, counteracted the impairment of nerve conduction velocity (NCV) and thermal threshold, restored skin innervation density, and improved Na(+),K(+)-ATPase activity and mRNA levels of myelin proteins, such as glycoprotein zero and peripheral myelin protein 22, suggesting that these neuroactive steroids, might be useful protective agents in diabetic neuropathy. Interestingly, different receptors seem to be involved in these effects. Thus, while the expression of myelin proteins and Na(+),K(+)-ATPase activity are only stimulated by P and DHP (i.e. two neuroactive steroids interacting with P receptor, PR), NCV, thermal nociceptive threshold and intra-epidermal nerve fiber (IENF) density are also affected by THP, which interacts with GABA-A receptor. Because, a therapeutic approach with specific synthetic receptor ligands could avoid the typical side effects of steroids, future experiments will be devoted to evaluating the role of PR and GABA-A receptor in these protective effects.

Beneficial effects of melatonin in protecting against cyclosporine A-induced cardiotoxicity are receptor mediated

Melatonin, the chief product secreted by pineal gland, is capable of reducing free radical damage by acting directly as a free radical scavenger, and indirectly, by stimulating of antioxidant enzymes. Cyclosporine A (CsA) is the most widely used immunosuppressive drug, but its therapeutic use has several side effects including, i.e. nephrotoxicity and cardiotoxicity. This study was designed to examine the beneficial effects of melatonin in preventing CsA-induced cardiotoxicity. Additionally, we investigated the ability of melatonin to protect the rat heart via melatonin receptor. In one group of Wistar rats, melatonin (1 mg/kg/day i.p.) was administered concurrently with CsA (15 mg/kg/day s.c.) for 21 days. In another group of animals, melatonin was injected with CsA and luzindole, an antagonist of melatonin receptors. Oxidative stress in heart tissue homogenates was estimated using thiobarbituric acid reactive substances (TBARS), reduced glutathione levels and antioxidant enzyme activities including catalase and superoxide dismutase. CsA administration for 21 days produced elevated levels of TBARS, marked depletion of cardiac antioxidant enzymes and caused morphological alterations in myocardial fibers. Melatonin markedly reduced TBARS levels, increased the antioxidant enzyme levels and normalized altered cardiac morphology. The protective effects of melatonin were lost when the animals received the melatonin receptor antagonist. In conclusion our study shows that, (a) melatonin significantly reduces CsA cardiotoxicity, and (b) the reduction in CsA-induced cardiotoxicity was mediated by the binding of melatonin to its membrane receptors.

Role of mast cells in wound healing process after glass-fiber composite implant in rats

Glass-fiber composites are frequently used in dentistry. In order to evaluate their biocompatibility we tested, in an experimental model "in vivo", their tissue response pointing our attention on presence of mast cells (MCs) and fibrotic process. Sprague Dawley rats were used for the experimental design. The fibers were introduced in a subcutaneous pocket along the middle dorsal line between the two scapulas for 7, 14 or 21 days. At the end of the treatments the skins were excised and then processed for Toluidine Blue, to determine the presence of MCs, and Picrosirius Red staining, to evaluate the presence of fibrotic tissue. Our preliminary results showed and increase of both MC number and deposition of collagen type I, which characterized the fibrotic tissue. So, subsequent aims of our study were to evaluate the role played by MCs in tissue fibrosis and to give a possible explanation regarding the mechanisms that were responsible of biological response observed, through the analyses of some proteins, such as metalloproteinase-2 (MMP-2), its inhibitor (TIMP-2) and transforming growth factor-beta (TGF-beta). Our data confirmed the involvement of TGF-beta, released by MCs, in the disruption of the equilibrium between MMP-2 and TIMP-2 that were implicated in the enhancement of fibrosis. In summary, this study demonstrate that this type of materials induced an inflammatory response at the site of implant and help to clarify what type of mechanism and which proteins are involved in this biological response. Nevertheless, more extensive investigations are in progress to better evaluate the inflammatory process.

Chest wall kinematics, respiratory muscle action and dyspnoea during arm vs. leg exercise in humans

AIM

We hypothesize that different patterns of chest wall (CW) kinematics and respiratory muscle coordination contribute to sensation of dyspnoea during unsupported arm exercise (UAE) and leg exercise (LE).

METHODS

In six volunteer healthy subjects, we evaluated the volumes of chest wall (V(cw)) and its compartments, the pulmonary apposed rib cage (V(rc,p)), the diaphragm-abdomen apposed rib cage (V(rc,a)) and the abdomen (V(ab)), by optoelectronic plethysmography. Oesophageal, gastric and trans-diaphragmatic pressures were simultaneously measured. Chest wall relaxation line allowed the measure of peak rib cage inspiratory muscle, expiratory muscle and abdominal muscle pressures. The loop V(rc,p)/V(rc,a) allowed the calculation of rib cage distortion. Dyspnoea was assessed by a modified Borg scale.

RESULTS

There were some differences and similarities between UAE and LE. Unlike LE with UAE: (i) V(cw) and V(rc,p) at end inspiration did not increase, whereas a decrease in V(rc,p) contributed to decreasing CW end expiratory volume; (ii) pressure production of inspiratory rib cage muscles did not significantly increase from quiet breathing. Not unlike LE, the diaphragm limited its inspiratory contribution to ventilation with UAE with no consistent difference in rib cage distortion between UAE and LE. Finally, changes in abdominal muscle pressure, and inspiratory rib cage muscle pressure predicted 62% and 41.4% of the variability in Borg score with UAE and LE, respectively (P < 0.01).

CONCLUSION

Leg exercise and UAE are associated with different patterns of CW kinematics, respiratory muscle coordination, and production of dyspnoea.

Role of carbon monoxide and biliverdin in renal ischemia/reperfusion injury

Heme oxygenase (HO) isoforms catalyze the conversion of heme to carbon monoxide (CO) and biliverdin/bilirubin with a concurrent release of iron. There is strong evidence that HO activity and products play a major role in renoprotection, however the exact molecular mechanisms underlying the beneficial effects exerted by this pathway are not fully understood. This review is aimed at illustrating the possible mechanism/s by which HO is renoprotective in the context of ischemia/reperfusion. We will first analyze the effects of exogenous administration of bilirubin/biliverdin and CO and then describe their biological activities once generated endogenously following stimulation of the HO pathway by either pharmacological means or gene targeting-mediated approaches.

Changes in extracellular matrix in subcutaneous small resistance arteries of patients with primary aldosteronism

CONTEXT AND OBJECTIVE

It has been previously demonstrated that aldosterone may possess a strong profibrotic action in vitro and in animal models of genetic or experimental hypertension. Our aim was to evaluate whether such a profibrotic action is present also in the human microcirculation.

DESIGN AND PATIENTS

We investigated 13 patients with primary aldosteronism, seven patients with essential hypertension, and 10 normotensive controls. All subjects were submitted to a biopsy of gluteal sc fat tissue. Small resistance arteries were dissected and mounted on an isometric myograph, and the tunica media to internal lumen ratio was measured.

MAIN OUTCOME MEASURES

The total collagen content within the tunica media was detected (Sirius red staining and image analysis), and collagen subtypes were evaluated using polarized light microscopy; under this condition thicker type I collagen fibers appear orange or red, whereas thinner type III collagen fibers are yellow or green.

RESULTS

Tunica media to internal lumen ratio was significantly increased in primary aldosteronism and in essential hypertension compared with normotensive controls. Clinic blood pressure values were similar in primary aldosteronism and in essential hypertension, and greater than in normotensive controls. Normotensive controls had less total and type III collagen (3.23 +/- 0.58 and 1.60 +/- 0.22%, respectively) in respect to the two hypertensive groups (P < 0.001). Total collagen and type III vascular collagen were significantly greater in primary aldosteronism (total collagen, 8.17 +/- 1.38%; type III collagen, 6.06 +/- 0.74%; P < 0.05) than in essential hypertension (total collagen, 6.84 +/- 1.15%; type III collagen, 5.25 +/- 0.80%).

CONCLUSIONS

Our results indicate that, in small resistance arteries of patients with primary aldosteronism, a pronounced fibrosis may be detected, even more evident than in blood-pressure-matched patients with essential hypertension.

Bimoclomol ameliorates mercuric chloride nephrotoxicity through recruitment of stress proteins

Bimoclomol (BIM), is a stress proteins coinducer, that acts synergistically with a mild stressor to activate cytoprotective stress proteins. BIM has been successfully utilized in animal models for the treatment of various nervous, cardiac and cerebrovascular diseases. Mercuric chloride (HgCl(2)) induces acute renal failure in rats by a single dosage. The present in vivo study was conducted to assess the efficacy of BIM against acute HgCl(2) nephrotoxicity. At different times after BIM and/or HgCl(2) exposure we evaluated renal morphology and the localization/abundance of three stress proteins (HSP72, GRP75, HSP60) by electron microscopy, immunohistochemistry and Western blot analysis. BIM delivery to rats 6h before mercury, ameliorated damage to renal ultrastructure, with recovery of tubular and mitochondrial membranes 24h after mercury treatment. In rats pretreated with BIM prior to HgCl(2) exposure, HSP72 was significantly overexpressed in proximal tubules in a time-dependent manner. In contrast, the amounts of GRP75 and HSP60 after BIM pretreatment were comparable to the group treated with mercury alone, but these stress proteins had translocated to the nuclei at 14 and 24h, respectively. These novel findings suggest that BIM mitigates HgCl(2) nephrotoxicity in rats through the early recruitment of stress proteins in midcortical proximal tubules that are the main renal mercury-targets.

Tubular stress proteins and nitric oxide synthase expression in rat kidney exposed to mercuric chloride and melatonin

Stress proteins such as HSP70 members (HSP72 and GRP75) and metallothionein (MT) protect the kidney against oxidative damage and harmful metals, whereas inducible nitric oxide synthase (iNOS) regulates tubular functions. A single dose of mercuric chloride (HgCl(2)) can cause acute renal failure in rats, its main target being the proximal tubule. Oxidative damage has been proposed as one of its pathogenic mechanisms. In this study we tested whether melatonin (MEL), a powerful antioxidant compound, is effective against HgCl(2) nephrotoxicity. Rats were treated with saline, HgCl(2) (3.5 mg/kg), MEL (5 mg/kg), and MEL + HgCl(2) and examined after 24 hr for HSP72, GRP75, MT, and iNOS by immunohistochemistry and immunoblotting. Tubular effects of the treatment were then characterized by ultrastructure. In the HgCl(2) group, all markers were overexpressed in convoluted proximal tubules and sometimes in distal tubules. In the MEL + HgCl(2) group, GRP75 and iNOS decreased in convoluted and straight proximal tubules, whereas HSP72 and MT persisted more than the saline and MEL-only groups. Tubular damage and mitochondrial morphometry were improved by MEL pretreatment. In conclusion, the beneficial effect of MEL against HgCl(2) nephrotoxicity was outlined morphologically and by the reduction of the tubular expression of stress proteins and iNOS. These markers could represent sensitive recovery index against mercury damage.

Expression of non-muscle myosin heavy chain in rat heart after immunosuppressive treatment

Myosins constitute a large family of molecular motors, hydrolyzing ATP and producing cellular movement. To date, a large number of novel isoforms have been found in muscle and non-muscle cells. Among non-muscle myosins, non-muscle myosin heavy chain (NMHC) II-A and II-B have been well characterized. An additional member of NMHC II-B, with a molecular weight of 220 kDa, was recently identified in bovine skeletal muscle. NMHC II-B proteins, in particular, have been suggested to be a useful early molecular marker for the detection of pathological conditions during acute or chronic organ rejection in which fibrotic changes occur. Since it is known that treatment with cyclosporine A (CsA), an immunosuppressive drug successfully used for preventing organ rejection and autoimmune diseases, is often associated with several side effects (hypertension and nephrotoxicity), the aims of this study were: (1) to demonstrate the homology of the new NMHC protein (220 kDa) in other mammalian species, such as Wistar rats; (2) to evaluate, by morphological and immunohistochemical studies, the possible changes induced by CsA treatment in NMHC protein (220 kDa) cellular localization and/or in its expression levels in myocardial tissue. First of all, our results showed a greater homology of the new NMHC within the same isoforms across species and between isoforms in the same specie; moreover, we observed that this protein increased following CsA treatment. This could be explained as a tentative of cardiac tissue to maintain the structural integrity of intercalated disks and so the contraction/relaxation process.

Protective Role of Polyphenols in Cyclosporine A-induced Nephrotoxicity During Rat Pregnancy

The aim of this study was to evaluate the adverse effects of cyclosporine A (CsA) toward renal morphogenesis and to test the renoprotective natural antioxidants such as provinol (PV). Pregnant rats were divided into four groups. Group I was injected SC with olive oil. Group II was treated with oral administration of PV and was used as control. Group III animals were injected SC daily with CsA, and group IV animals were injected daily with CsA and PV for 21 days of pregnancy. Five pups per litter were killed and the kidneys removed and treated by morphological and immunohistochemical (IHC) methods. IHC analysis considered two proteins responsible for nephrotoxicity in adult rats: inducible nitric oxide (iNOS) and matrix metalloproteinase-2 (MMP2). Pregnancy outcomes among CsA-treated rats demonstrated a reduced number of pups. Pups that were exposed antenatally to CsA presented several pathologic findings in all immature parenchyma and an increase in iNOS and MMP2 expression. These side effects were not observed in kidney of litters born from CsA + PV-treated mothers. Our study indicates that CsA induces morphological alterations in renal parenchyma of neonates and that PV plays a protective role against these side effects.

Breathing pattern and kinematics in normal subjects during speech, singing and loud whispering

AIMS

We used for the first time a non-invasive optoelectronic plethysmography to assess breathing movements and to provide a quantitative description of chest wall kinematics during phonation.

METHODS

Volumes of different chest wall compartments (abdomen and lung apposed to rib cage and abdomen) were assessed using optoelectronic plethysmography in 16 normal Italians (eight men) during reading, singing and high-effort whispering (HW).

RESULTS

During phonation the breathing pattern was different from quiet breathing and exercise. (1) During phonation, tidal volume and expiratory time increased while inspiratory time decreased. The expiratory volume changes and flows during HW were considerably greater than during vocalization. During HW, the overall end-expiratory thoracic volume significantly decreased as a result of decreased volume of all compartments and essentially impinged on the maximal expiratory flow-volume curve. (2) While, as previously shown, during exercise the expired volume is due entirely to the abdomen, during phonation all three chest wall compartments contribute to it. Under all conditions studied breathing was, on average, more costal in females than in males but this was mainly related to different size rather than gender per se.

CONCLUSIONS

Physical characteristics have a greater importance than gender in determining breathing pattern and chest wall kinematics during phonation. The activity of the control of expiration during phonation is more complex than during exercise.

Stress proteins expression in rat kidney and liver chronically exposed to aluminium sulphate

Aluminium (Al) is the third most widespread metal in the environment. It is toxic for the brain, bone and haematological system but unfortunately very little data exist for other organs. Stress proteins are induced or enhanced against metal toxicity with an essential role in the recovery of organules and other cellular proteins. This immunohistochemical study was performed to analyze the distribution of three stress proteins (HSP25, HSP72, GRP75) in rat kidney and liver orally exposed to Al sulphate daily for 3 and 6 months. Al-induced alterations were further studied by histopathology (H-E, PAS, Perl's, Masson) and ultrastructural morphometry. In the kidney: HSP25 was enhanced in proximal tubules after 6 months Al-exposure when abnormal brush borders were observed; HSP72 was induced in proximal tubules only after long Al-treatment; GRP75 was raised in midcortical area sometimes within nuclei. Furthermore, lysosomal and lipofuscins densities increased in the juxtamedullary tubules after 3 months Al exposure with respect to controls. In the liver: Perl's-positive deposits and fibrosis became evident after Al treatment. HSP25 was very weak; HSP72 focal in pericentral hepatocytes at 3 months and induced also in Kupffer cells at 6 months; GRP75 diffuse in periportal hepatocytes and non parenchymal cells at 6 months. Prolonged Al exposure stimulated stress proteins strictly organ-dependently in the rat. Their distribution in kidney and liver seems related to cumulative sublethal effects induced by metal and could be a sensitive index of Al susceptibility of these organs.

Exposure to aluminium changes the NADPH-diaphorase/ NPY pattern in the rat cerebral cortex

Aluminium (Al) impairs the glutamate-nitric oxide-cGMP pathway and reduces the number of nitroxidergic neurons in the rat somatosensory cortex. To understand better the effect of the time of exposure, we monitored the effect of aluminium administration on nitroxidergic neurons, identified by NADPH-diaphorase (NADPH-d) or by nitric oxide synthase (NOS) staining, after 0.5, 1, 2, 3, 6 and 12 months of aluminium administration. Since neuropeptide Y (NPY) is known to be colocalised with nitric oxide synthase in cortical neurons, the aim of this work was to study the effects of Al administration on the cortical expression of NADPH-d, nNOS, and NPY. NADPH-d or NOS positive neurons were found scattered in the cortex where they constituted about 1% of all neurons. Double staining using NADPH-d and NPY showed that almost all nitroxidergic neurons were co-localised with NPY neurons (NADPH-d/NPY double stained neurons) whereas some neurons were stained only with NPY (NPY single stained neurons) ; these were more numerous than NADPH-d/NPY double stained neurons. Al significantly reduced NADPH-d and nNOS positive neurons in the cerebral cortex time dependently, with the greatest effect appearing after 3 months. Also measured was the integrated optical density (IOD) of nNOS positive neurons showing a significant decrease of NOS immunostaining even in the remaining NOS positive neurons. The double staining experiment exhibited a decrease in NADPH-d/NPY double stained neurons with an apparent increase in NPY single stained neurons; these then decreased after 6-12 months. On the whole, the results confirm that Al impairs nitroxidergic pathways time dependently; moreover, the transient increase in NPY single stained neurons from 1 to 3 months suggests that there is an intraneuronal down-regulation of NOS, without affecting neuronal viability. In addition, the decrease in the NPY system found at 6 and 12 months may indicate that Al affected nitroxidergic and NPY systems at different times.

Protective role of melatonin in cyclosporine A-induced oxidative stress in rat liver

Cyclosporine A (CsA) is the most widely used immunosuppressive drug for preventing graft rejection and autoimmune disease. However, the therapeutic treatment induces several side effects such as nephrotoxicity, cardiotoxicity, hypertension and hepatotoxicity. Among possible mechanisms of CsA-induced hepatic damage, oxidative stress has been suggested. Melatonin (Mel) has been successfully used as a potent antioxidant against many pathophysiological states. This experimental study was performed to test, during CsA treatment, the alterations of some heat shock proteins (HSP) and the Mel antioxidant properties against CsA-induced injury. Rats were divided into four groups, which were treated respectively with olive oil, Mel alone, CsA and CsA plus Mel for 30 days. At the end of the treatments, the animals were killed and hepatic tissue was treated for morphological (haematoxylin-eosin), biochemical (reduced glutathione, GSH and malondialdehyde, MDA) and immunohistochemical (HSP60, HSP72, GRP75 and MT) analyses. The results indicate that CsA-induced hepatotoxicity was characterised by morphological alterations in tissue architecture, changes in GSH and MDA levels and increase in stress protein expression. In conclusion, our data suggest that the imbalance between production of free oxygen radicals and antioxidant defence systems, due to CsA administration, is a mechanism responsible for oxidative stress. Moreover, we show that Mel plays a protective action against CsA-induced oxidative stress, as supported by biochemical and immunohistochemical results.

Histochemical and immunohistochemical evaluation of gingival collagen and metalloproteinases in peri-implantitis

The extra-cellular matrix of the gingival tissue plays an important role in the homeostasis of dental implants. In this work we have studied immunohistochemically the distribution of collagen I-III-IV-V, tenascin, metalloproteinases (MMP) 1-3-8-13 and TIMP-1 in three groups of patients: (1) subjects with natural teeth (healthy periodontal tissue), (2) subjects with normal peri-implant mucosa and (3) subjects with clinically evident peri-implantitis. The immunolabelling for collagen I-III-IV showed a similar pattern in all three groups. The labelling for collagen V increased in lamina propria of healthy peri-implant tissue and peri-implantitis. Tenascin immunolabelling in healthy and peri-implant tissues was scattered in lamina propria. In peri-implantitis tenascin immunolabelling increased mainly near to the basal lamina. The MMP-1-3-8 and TIMP-1 immunolabelling were very faint and localized in the stroma in all three groups. In healthy and peri-implant tissues MMP-13 immunolabelling was found in the lamina propria whereas in peri-implantitis MMP-13 immunolabelling was also in epithelium. On the whole, these data suggest that in the extracellular matrix of peri-implantitis there are alterations of collagen V, tenascin and MMP-13 patterns.

The protective effect of caffeic acid phenethyl ester against cyclosporine A-induced cardiotoxicity in rats

Cyclosporine A (CsA) is the immunosuppressor, which is most frequently used in transplant surgery and in the treatment of autoimmune diseases. Oxidative stress has been considered as one of the possible mechanisms of CsA-induced cardiotoxicity. The present investigation examines the ability of caffeic acid phenethyl ester (CAPE), which is an active component of propolis extracts, as a natural antioxidant to protect against CsA-induced oxidative stress and cardiotoxicity. CsA cardiotoxicity was induced by subcutaneous injection of CsA at a dose of 15 mg/kg/body weight daily for 21 days in rats. Cardiotoxicity was evaluated by morphological and biochemical studies. CsA treated rats showed degenerative changes with cardiac fibrosis localized around the fibers. These latters were disorganised and the network was disappeared. The ROS production was increased whereas cytochrome-c-oxidase decreased. The expression and levels of matrix metalloproteinase 2 (MMP2) were increased whereas those of its inhibitor were downregulated. CAPE subcutaneous administration (15 micromol/kg/day) improved cardiac cytoarchitecture, decreased the levels and the expression of MMP2, and increased those of TIMP2 proteins. Moreover, it increased cytochrome-c-oxidase activity and decreased ROS production. These results suggest that CAPE could have protective effect against CsA-induced cardiotoxicity.