Systemic administration of high-molecular weight hyaluronan stimulates wound healing in genetically diabetic mice

Hyaluronic acid (HA), an essential component of the extracellular matrix, is an efficient space filler that maintains hydration, serves as a substrate for assembly of proteoglycans and is involved in wound healing. Although numerous pieces of evidence demonstrate beneficial effects in promoting wound healing in diabetes, a systemic approach has never been tested. We used an incisional wound healing model in genetically diabetic mice to test the effects of systemic injection of HA. Diabetic (n = 56) and normoglycemic (n = 56) mice were subjected to incision and randomized (8 groups of 7 animals each) to receive HA at different doses, 7.5, 15 and 30 mg/kg/i.p., or vehicle (0.9% NaCl solution) for 12 days. At the end of the experiment animals were sacrificed and skin wounds were excised for histological, biochemical and molecular analysis. Histology revealed that the most effective dose to improve wound repair and angiogenesis in diabetic mice was 30 mg/kg. Furthermore HA injection (30 mg/kg) improved the altered healing pattern in diabetic animals, increased skin remodeling proteins TGF-β and transglutaminase-II and restored the altered expression of cyclin B1/Cdc2 complex. Evaluation of skin from diabetic animals injected with HA revealed also an increase in HA content, suggesting that systemic injection may be able to restore the reduced intracellular HA pool of diabetic mice. Finally HA markedly improved skin mechanical properties. These promising results, if confirmed in a clinical setting, may improve the care and management of diabetic patients.     

Activation of the EPOR-β common receptor complex by cibinetide ameliorates impaired wound healing in mice with genetic diabetes

Diabetes is characterized by poor wound healing which currently lacks an efficacious treatment. The innate repair receptor (IRR) is a master regulator of tissue protection and repair which is expressed as a response injury or metabolic stress, including in diabetes. Activation of the IRR might provide benefit for diabetic wound healing. A specific IRR agonist cibinetide was administered in an incisional wound healing model performed mice with genetic diabetes (db⁺/db⁺) and compared to the normal wild-type. Animals were treated daily with cibinetide (30 μg/kg/s.c.) or vehicle and euthanized 3, 7, and 14 days after the injury to quantitate vascular endothelial growth factor (VEGF), malondialdehyde (MAL), phospho-Akt (pAkt), phospho e-NOS (p-eNOS), and nitrite/nitrate content within the wound. Additional evaluations included quantification of skin histological change, angiogenesis, scar strength, and time to complete wound closure. Throughout the wound healing process diabetic animals treated with vehicle exhibited increased wound MAL with reduced VEGF, pAkt, peNOS and nitrite/nitrate, all associated with poor re-epitheliziation, angiogenesis, and wound breaking strength. Cibenitide administration significantly improved these abnormalities. The results suggest that cibinetide-mediated IRR activation may represent an interesting strategy to treat diabetes-associated wound healing.     

Distribution and abundance of fish larvae in the northern Ionian Sea (Eastern Mediterranean)

The purpose of this paper was to study the spatial distribution, abundance and composition of fish larvae in the northern Ionian Sea. Samples were collected to the 600 m depth with an electronic multinet BIONESS during the “INTERREG Italia-Grecia” oceanographic cruise carried out in March 2000 off the Apulian Italian coast. A total of 46 species of teleost early stages were collected, belonging to 38 genera and 22 families. Over 52% of the larvae identified were mesopelagic species, almost 27% were demersal and about 21% pelagic. A total of 307 myctophids, 69 clupeids and 61 gadid post-larvae dominated the community. Benthosema glaciale (mean 6.1 mm SL) was the most abundant species (21.6%), the most frequent in the samples (28.8%), and dominant in the whole study area (mean 1.4 ind/100 m³). Particular attention was given to the horizontal and vertical distribution and abundance of the three dominant post-larval species: Benthosema glaciale, Sprattus sprattus sprattus and Notoscopelus elongatus. The Pearson coefficient (R = 0.734) showed a high correlation between total zooplankton and fish larval assemblages in terms of spatial distribution abundance values. Regarding the vertical distribution of fish larvae, Sorensen’s index (S = 0.69) showed that fish larvae and total zooplankton abundance peaks co-occurred along the water column.     

Short-term changes in zooplankton community in Paso Ancho basin (Strait of Magellan): functional trophic structure and diel vertical migration

Knowledge on community structure oriented to describe energy flow during late summer season in Paso Ancho basin (Strait of Magellan) is scarce and particularly affected by vertical diel migration (VDM). The main aim of this work is to identify the VDM patterns of selected species and functional feeding groups of mesozooplankton, collected by the electronic multinet BIONESS in 1995. Detailed studies were carried out on keystone components of the community: 7 species of copepods (Ctenocalanus citer, Drepanopus forcipatus, Metridia lucens, Clausocalanus brevipes, Scolecithricella minor, Paraeuchaeta antarctica, Calanus simillimus), one ostracod (Discoconchoecia elegans), one chaetognath (Sagitta tasmanica), one euphausiid (Euphausia vallentini), and two polychaetes (Pelagobia longicirrata, Tomopteris planktonis). Unexpected deviations from the classic pattern reported in literature were uncovered. The shallow layer mesozooplankton at night, although dominated by exclusively or preferentially herbivores, particularly by E. vallentini, was not represented by several species known as herbivores that remained in the deep layer throughout the day cycle. The deep-layer zooplankton throughout the day cycle was well represented by carnivores, detritivores, and omnivores. It is suggested that during low-chlorophyll summer conditions, the composition of functional groups and diet, and VDM patterns changed to take advantage of sinking phytoplankton and picoplankton in deep layers. Pelagic-benthic coupling would be strengthened due to animals that suppressed their vertical daily rise to the shallow layer at nights but remained in the deep layers to feed on a rain of particulate organic matter and other non-migrant zooplankton.     

Species diversity, spatial distribution, and assemblages of zooplankton within the Strait of Magellan in austral summer

The main aim of this work was to identify zooplankton assemblages by means of statistical testing and associate them with hydrographic properties of the Strait of Magellan and its microbasins. Zooplankton samples were collected by the R/V Cariboo in late austral summer 1991. Nineteen stations were sampled by BIONESS from the surface layer to 900 m depth, along the main longitudinal axis of the Strait of Magellan. There was a marked regional-scale pattern in zooplankton species diversity and richness, related to the hydrographical features of the Strait and its sub-basins. Six groups of samples were identified by cluster analysis in terms of zooplankton structure, and related to sea-water properties of temperature, salinity, and Chl a (Sperman’s correlation coefficient). Plankton assemblages of the Strait of Magellan seem closely linked to the remote sub-Antarctic and adjacent ocean biota, but populations may have independent evolutionary lines and population dynamics.     

The reduction of myocardial damage and leukocyte polymorphonuclear accumulation following coronary artery occlusion by the tyrosine kinase inhibitor tyrphostin AG 556

We investigated the effects of tyrophostin AG 556, a tyrosine kinase inhibitor, on the phenomenon of leukocyte accumulation during ischaemia and reperfusion of the myocardium. Male anaesthetized rats were subjected to total occlusion (45 min) of the left main coronary artery followed by 5 h reperfusion (MI/R). Sham myocardial ischaemia-reperfusion rats (Sham MI/R) were used as controls. Myocardial necrosis, myocardial myeloperoxidase activity (MPO), serum creatinine phosphokinase activity (CPK) serum Tumor Necrosis Factor (TNF-alpha) and Interleukin 6 (IL-6), cardiac intercellular adhesion molecule-1 (ICAM-1) and TNF-alpha expression and myocardial contractility (left ventricle dP/dt(max)) were evaluated. Myocardial ischaemia plus reperfusion in untreated rats produced marked myocardial necrosis, increased serum CPK activity (196.5 +/- 19 U/100 ml, at the end of reperfusion) and myeloperoxidase activity (MPO, a marker of leukocyte accumulation) both in the area-at-risk (4.5 +/- 0.5 U/g/tissue) and in necrotic area (8.2 +/- 1.2 U/g/tissue), reduced myocardial contractility (1,706 +/- 52 mmHg/s, at the end of reperfusion) and induced a marked increase in the serum levels of TNF-alpha (1,950 +/- 97 pg/ml, at 1 h of reperfusion) and IL-6 (998 +/- 16 U/ml, at the end of reperfusion). Finally, myocardial ischaemia-reperfusion injury also increased cardiac mRNA for TNF-alpha and ICAM-1 in the myocardium-at risk. Tyrphostin AG 556 (0.5, 1 and 2 mg/kg subcutaneously 5 min after the onset of reperfusion) lowered myocardial necrosis and myeloperoxidase activity in the area-at-risk (1.5 +/- 0.2 U/g/tissue, following the highest dose) and in necrotic area (2.9 +/- 0.3 U/g/tissue following the highest dose), decreased serum CPK activity (96 +/- 9 U/100 ml, at the end of reperfusion), lowered serum TNF-alpha and IL-6, increased myocardial contractility (2,096 +/- 88 mmHg s, at the end of reperfusion) and reduced cardiac mRNA levels for TNF-alpha and ICAM-1. The present data suggest that tyrosine kinase inhibitors protect against myocardial ischaemia-reperfusion injury by reducing leukocyte accumulation to the ischaemic myocardium.     

Composition,abundance and distribution of holoplanktonic polychaetes within the Strait of Magellan (southern America) in austral summer

This study enlarge the knowledge on species composition, distribution and community structure of pelagic polychaetes on the basis of finely stratified spatial sampling representing austral summer conditions in the Strait of Magellan. Zooplankton samples were collected in late austral summer 1995. A total of 56,489 pelagic polychaete specimens were collected. Eight holopelagic polychaete taxa were recorded in addition to Spionidae and Terebellidae larvae and reproductive stolons of Autolytinae. Pelagobia longicirrata (Lopadorhynchidae) was the most abundant species, representing about 96 % (54,092 specimens, 184.6 ind. 100 m^?3) of all individuals, followed by Tomopteris planktonis (Tomopteridae) at 3 % (1,725 specimens, 5.9 ind. 100 m^?3). The longest measured individuals belonged to T. planktonis, which also showed the largest size range, whereas the smallest individuals belonged to P. longicirrata. Spatial distribution of polychaetes in terms of abundance was not related to bottom depth, but rather the number of taxa was lower in the central part of the Strait. P. longicirrata and T. planktonis were negatively related to chlorophyll a. In addition, the first was negatively related to temperature instead the second was positively affected by salinity. Polychaetes were widely distributed in both epi- and mesopelagic realms, whereas they were almost absent above 80 m depth. Both of the most abundant species were concentrated in the deepest layers sampled (below 100 m) throughout day and night hours without showing any specific migratory behavior.     

Protective effects of SP600125 a new inhibitor of c-jun N-terminal kinase (JNK) and extracellular-regulated kinase (ERK1/2) in an experimental model of cerulein-induced pancreatitis

Extracellular regulated kinases (ERK1/2) and c-Jun N-terminal Kinases (JNK), are generally considered to play a key role in signal transduction pathways activated by a wide range of stimuli. We studied the effects of SP600125, a novel inhibitor of both JNK and ERK1/2, in male C57/BL6 mice given with an hyper-stimulating dose of cerulein (50 microg/kg for each of four injections at hourly intervals) to elicit secretagogue-induced pancreatitis. A control group received four intra-peritoneal injections of 0.9% saline at hourly intervals. Animals were randomized to receive either SP600125 (15 mg/kg i.p. administered 2 h before and 30 min after the first injection of cerulein) or its vehicle (1 ml/kg of a 10% DMSO/NaCl solution). A group of animals was killed 30 minutes after the last cerulein injection to evaluate pancreatic JNK and ERK1/2 activation by Western Blot analysis. Another group was sacrificed 2 hours after the last cerulein injection to evaluate serum lipase and amylase levels, pancreas oedema, pancreatic content of Tumor Necrosis Factor-alpha (TNF-alpha) and Intercellular adhesion molecule-1 (ICAM-1) and the histological alterations. SP600125 inhibited almost totally JNK activation (90%) and partially ERK1/2 activation (45%), reduced the serum lipase and amylase levels and the degree of oedema, blunted the increased pancreatic content of TNF-alpha and ICAM-1 and protected against the histological damage. Our data confirm that both JNK and ERK1/2 activation plays a key role in acute pancreatitis and that SP600125 may represent a potential therapeutic approach to the treatment of patients at high risk of developing this life-threatening condition.     

Levetiracetam protects against kainic acid-induced toxicity

We investigated the Levetiracetam (LVT) ability to protect the brain against kainic acid (KA) induced neurotoxicity. Brain injury was induced by intraperitoneal administration of KA (10 mg/kg). Sham brain injury rats were used as controls. Animals were randomized to receive either LVT (50 mg/kg) or its vehicle (1 ml/kg) 30 min. before KA administration. Animals were sacrificed 6 hours after KA injection to measure brain malonildialdehyde (MDA), glutathione levels (GSH) and the mRNA for interleukin-1beta (IL-1beta) in the cortex and in the diencephalon. Behavioral changes were also monitored. Intraperitoneal administration of LVT decreased significantly MDA in the cortex (KA + vehicle = 0.25 +/- 0.03 nmol/mg protein; KA + LVT = 0.13 +/- 0.01 nmol/mg protein; P < 0.005), and in the diencephalons (KA + vehicle = 1,01 +/- 0.2 nmol/mg protein; KA + LVT = 0,33 +/- 0,08 nmol/mg protein; P < 0.005), prevented the brain loss of GSH in both cortex (KA + vehicle = 5 +/- 1 micromol/g protein; KA + LVT = 15 +/- 2 micromol/g protein; P < 0.005) and diencephalons (KA + vehicle = 9 +/- 0.8 micromol/g protein; KA + LVT = 13 +/- 0.3 micromol/g protein; P < 0.05), reduced brain IL-1beta mRNA and markedly controlled seizures. Histological analysis showed a reduction of cell damage in LVT treated samples. The present data indicate that LVT displays neuro-protective effects against KA induced brain toxicity and suggest that these effects are mediated, at least in part, by inhibition of lipid peroxidation.