Effects of moderate‐ and high‐intensity chronic exercise on brain‐derived neurotrophic factor expression in fast and slow muscles

Introduction: Brain‐derived neurotrophic factor (BDNF) protein expression is sensitive to cellular activity. In the sedentary state, BDNF expression is affected by the muscle phenotype. Methods: Eighteen Wistar rats were divided into the following 3 groups: sedentary (S); moderate‐intensity training (MIT); and high‐intensity training (HIT). The training protocol lasted 8 weeks. Forty‐eight hours after training, total RNA and protein levels in the soleus and plantaris muscles were obtained. Results: In the plantaris, the BDNF protein level was lower in the HIT than in the S group (P < 0.05). A similar effect was found in the soleus (without significant difference). In the soleus, higher Bdnf mRNA levels were found in the HIT group (P < 0.001 vs. S and MIT groups). In the plantaris muscle, similar Bdnf mRNA levels were found in all groups. Conclusions: These results indicate that high‐intensity chronic exercise reduces BDNF protein level in fast muscles and increases Bdnf mRNA levels in slow muscles. Muscle Nerve 53: 446–451, 2016     

Regression of retinal capillaries following N‐methyl‐D‐aspartate‐induced neurotoxicity in the neonatal rat retina

Degeneration of retinal capillaries occurs following N‐methyl‐D ‐aspartate (NMDA)‐induced retinal neurotoxicity, and the degree of capillary degeneration decreases in an age‐dependent manner. To determine the role of vascular endothelial growth factor (VEGF) in the high susceptibility of capillaries to neuronal damage during the early postnatal stage, this study compares the vascular regression patterns between NMDA‐treated retinas and retinas treated with N‐[2‐chloro‐4‐{(6,7‐dimethoxy‐4‐quinazolinyl)oxy}phenyl]‐N′‐propylurea (KRN633), a VEGF receptor tyrosine kinase inhibitor, in neonatal rats. Two days after a single intravitreal injection of NMDA (200 nmol/eye) on postnatal day (P) 7, substantial retinal neuron loss and delayed expansion of the retinal vascular bed were observed. The reduction in the capillary density in the central retina reached statistical significance 4 days after NMDA treatment. In retinas of rats injected subcutaneously with KRN633 (10 mg/kg) on P7 and P8, simplified vasculature attributable to capillary regression and prevention of endothelial cell growth were seen on P9, whereas no visible changes in the morphology of the retinal layers were observed. The degree of capillary degeneration in NMDA‐treated retinas was less than that in KRN633‐treated retinas. No apparent changes in immunoreactivities for VEGF were found 2 days after NMDA treatment. These results indicate that neuronal cell loss in the retina precedes retinal capillary degeneration following NMDA treatment, and VEGF‐dependent immature capillaries might be more susceptible to NMDA‐induced neuronal damage. © 2014 Wiley Periodicals, Inc.     

Acute exercise adjustments of cardiovascular autonomic control in diabetic rats

Introduction: We evaluated the role of cardiovascular autonomic changes in hemodynamics at rest and in response to exercise in streptozotocin‐induced diabetic rats. Methods: Male Wistar rats were divided into nondiabetic (ND, n = 8) and diabetic (D, n = 8) groups. Arterial pressure signals were recorded in the basal state and after atropine or propranolol injections at rest, during exercise and during recovery. Results: At rest, vagal tonus was reduced in D (37 ± 3 bpm) in comparison with the ND group (61 ± 9 bpm). Heart rate during exercise was lower in D in relation to ND rats associated with reduced vagal withdrawal in the D group. The D rats had an increase in vagal tonus in the recovery period (49 ± 6 bpm). Conclusions: Exercise‐induced hemodynamic adjustment impairment in diabetic rats was associated with reduced cardiac vagal control. The vagal dysfunction was attenuated after aerobic exercise, reinforcing the positive role of this approach in the management of cardiovascular risk in diabetics. Muscle Nerve 46: 96–101, 2012     

Physical exercise during muscle regeneration improves recovery of the slow/oxidative phenotype

Introduction: As skeletal muscle mass recovery after extensive injury is improved by contractile activity, we explored whether concomitant exercise accelerates recovery of the contractile and metabolic phenotypes after muscle injury. Methods: After notexin‐induced degeneration of a soleus muscle, Wistar rats were assigned to active (running exercise) or sedentary groups. Myosin heavy chains (MHC), metabolic enzymes, and calcineurin were studied during muscle regeneration at different time points. Results: The mature MHC profile recovered earlier in active rats (21 days after injury) than in sedentary rats (42 days). Calcineurin was higher in the active degenerated than in the sedentary degenerated muscles at day 14. Citrate synthase and total lactate dehydrogenase (LDH) activity decreased after injury and were similarly recovered in both active and sedentary groups at 14 or 42 days, respectively. H‐LDH isozyme activity recovered earlier in the active rats. Conclusions: Exercise improved recovery of the slow/oxidative phenotype after soleus muscle injury. Muscle Nerve 55 : 91–100, 2017     

High Intensity Physical Exercise before the Brain Ischemia Promotes Increase in Brain Injury

Studies have demonstrated the beneficial effects of light- and moderate-intensity physical exercise on the nervous system of animals with cerebral ischemia. To investigate the effects of two high-intensity physical exercise protocols, standardized for resistance and strength gain, in rats trained before cerebral ischemia induced by Bilateral Common Carotid Artery Occlusion (BCCAO). Forty-eight male Wistar rats were divided into two groups: with ischemia and without ischemia (sham). Both groups were subdivided into animals that performed high-intensity exercises in the muscle strength modality (I+Ex2; Sham+Ex2; n=16); animals submitted to high-intensity exercises in the aerobic modality (I+Ex1; Sham+Ex1; n=16), and animals that did not practice physical exercises - sedentary (I+Sed; Sham+Sed, n=16). Cerebral ischemia was induced using the BCCAO model. The physical training program used before the procedure was of high intensity, in the aerobic and muscular strength modalities, and was performed using a vertical ladder, for 4 weeks, 5 days per week. In order to process and stain the brain tissue, the Nissl method was used for neuron labeling and quantification in the cortex, striatum, and hippocampus. As for the animals’ body weight and the heart weight differences were found between the groups I+Ex2 and Sham+Ex2 (p<0.05). Data on neuron quantification in the cerebral cortex, dentate gyrus, and right and left striatum revealed significant differences between groups. High-intensity physical training in the strength gain modality promotes significant damage to the animal's brain when performed prior to BCCAO-induced cerebral ischemia.     

Selectively reshaping a muscle phenotype: functional overload of cat plantaris

Introduction: Functional overload (FO) of the fast plantaris muscle was studied in treadmill‐exercised (FO‐Ex) or sedentary (FO‐Sed) adult cats. Methods: Mechanical, phenotype, and kinematics analyses were performed. Results: Plantigrade vs. normal digitigrade posture was observed early post‐FO. Relative plantaris mass was greater in FO‐Sed (10%) and FO‐Ex (60%) cats than in controls 12 weeks post‐FO. Specific tension was similar across groups, indicating functional hypertrophy. Fiber size was greater, percent slow fibers higher, percent IIa myosin heavy chain (MHC) higher, and IIx MHC lower in FO‐Ex than controls. Twitch and half‐relaxation times were longer, and the frequency–tension curve shifted toward that observed in slow muscles. Electromyography (EMG) and tendon force amplitudes during stepping were larger, and the yield (lengthening) phase occurred at a longer muscle length before compared with after FO. Discussion: Reshaping the plantaris phenotype was highly dependent on the overload stimulus, indicating that electrical stimulation paradigms used during rehabilitation should be performed with the muscles under “loaded” conditions. Muscle Nerve, 2011     

Tumor cell‐associated neuropilin‐1 and vascular endothelial growth factor expression as determinants of tumor growth in neuroblastoma

We sought to characterize the expression of vascular endothelial growth factor (VEGF) and its receptors in neuroblastoma (NBL) and to correlate the results with N‐myc (MYCN) expression and in vivo growth of these tumors. Two representative human‐derived NBL cell lines, SK‐N‐AS (AS) with low and SK‐N‐DZ (DZ) with a high MYCN copy number, were used for the study. We examined their proliferation, VEGF and VEGF receptor expression in vitro and xenograft tumor growth in vivo. In parallel, human NBL specimens were analyzed for expression of VEGF and neuropilin‐1 (NRP‐1). DZ cells exhibited a 4‐fold higher proliferation rate than AS. In contrast, VEGF protein expression was significantly higher in AS cells. NRP‐1 was the only VEGF receptor produced in AS and DZ cells in vitro and in vivo. Both AS and DZ cells formed tumors in athymic mice but AS tumors grew 3.5 times larger than DZ tumors and had larger diameter tumor vessels. VEGF and NRP‐1 expression was also demonstrated in human NBL specimens. Our studies indicate that VEGF and VEGF receptor expression in NBL tumor cells are associated with tumor growth and that angiogenic factors may serve as a biological marker together with already established MYCN amplification.     

Load‐controlled moderate and high‐intensity resistance training programs provoke similar strength gains in young women

Introduction: While current exercise guidelines recommend progressive, high‐intensity resistance training (RT) to promote muscle hypertrophy and strength gains, controversy exists regarding the efficacy of lighter‐load RT. We compared 2 work‐matched RT interventions that differed in training intensity. Methods: Fifteen women underwent 10 weeks of unilateral knee extensor RT. One leg was trained at increasing intensity (intensity leg, InL, 50–80% 1‐repetition maximum [1‐RM]), and training progression in the contralateral leg (volume leg, VoL, 50% 1‐RM) was based on increasing training volumes. Quadriceps muscle size (ultrasound, dual energy X‐ray absorptiometry) and strength (isokinetic dynamometry) were assessed on 4 occasions. Results: Both training programs induced significant, yet comparable increases in muscle size (InL: +4.6–12%, VoL: +3.1–11%) and strength (InL: +10–16%, VoL: +10–14%). Conclusions: Training at lower than commonly suggested intensities may be an equally effective alternative form of RT. Factors other than training intensity, such as the total mechanical work during training, may strongly affect the training response. Muscle Nerve 51 : 92–101, 2015     

Effects of exercise training on hippocampus concentrations of insulin and IGF‐1 in diabetic rats

The present study investigated the role of swimming training on cerebral metabolism and hippocampus concentrations of insulin and IGF‐1 in diabetic rats. Wistar rats were divided in sedentary control (SC), trained control (TC), sedentary diabetic (SD), and trained diabetic (TD). Diabetes was induced by Alloxan (35 mg kg^?1 b.w.). Training program consisted in swimming 5 days/week, 1 h/day, 8 weeks, supporting a load corresponding to 90% of maximal lactate steady state (MLSS). For MLSS determination, rats were submitted to three sessions of 25‐min supporting loads of 4, 5, or 6% of body wt, with intervals of 1 week. Blood samples were collected every 5 min for lactate determination. An acute exercise test (25 min to 90% of MLSS) was done in 7th week to confirm the efficacy of training. All dependent variables were analyzed by one‐way analysis of variance (ANOVA) and a significance level of P < 0.05 was used for all comparisons. The Bonferroni test was used for post hoc comparisons. At the end of the training period, rats were sacrificed and sample blood was collected for determinations of serum glucose, insulin, GH, and IGF‐1. Samples of gastrocnemius muscle and liver were removed to evaluate glycogen content. Hippocampus was extracted to determinate glycogen, insulin, and IGF‐1 contents. Diabetes decreased serum GH, IGF‐1, and liver glycogen stores in SD. Diabetes also increased hippocampus glycogen and reduced hippocampus IGF‐1 content. Physical training recovered liver and hippocampus glycogen stores and promoted increases in serum IGF‐1 in TD group. Physical training restored hippocampus IGF‐1 content in diabetic group. It was concluded that in diabetic rats, physical training induces important metabolic and hormonal alterations that areassociated with an improvement in glucose homeostasis and with an increased activity in the systemic and hippocampus IGF‐1 peptide. © 2009 Wiley‐Liss, Inc.     

Spatial memory in sedentary and trained diabetic rats: Molecular mechanisms

Diabetes mellitus is a chronic disease that has been associated with memory loss, neurological disorders, and Alzheimer's disease. Some studies show the importance of physical exercise to prevent and minimize various neurological disorders. It is believed that the positive effects of exercise on brain functions are mediated by brain insulin and insulin‐like growth factor‐1 (IGF‐1) signaling. In this study, we investigate the role of swimming exercise training on hippocampus proteins related to insulin/IGF‐1 signaling pathway in Type 1 diabetic rats and its effects on spatial memory. Wistar rats were divided into four groups namely sedentary control, trained control, sedentary diabetic (SD), and trained diabetic (TD). Diabetes was induced by Alloxan (ALX) (32 mg/kg b.w.). The training program consisted in swimming 5 days/week, 1 h/day, per 6 weeks, supporting an overload corresponding to 90% of the anaerobic threshold. We employed ALX‐induced diabetic rats to explore learning and memory abilities using Morris water maze test. At the end of the training period, the rats were sacrificed 48 h after their last exercise bout when blood samples were collected for serum glucose, insulin, and IGF‐1 determinations. Hippocampus was extracted to determinate protein expression (IR, IGF‐1R, and APP) and phosphorylation (AKT‐1, AKT‐2, Tau, and β‐amyloide proteins) by Western Blot analysis. All dependent variables were analyzed by two‐way analysis of variance with significance level of 5%. Diabetes resulted in hyperglycemia and hypoinsulinemia in both SD and TD groups (P < 0.05); however, in the training‐induced group, there was a reduction in blood glucose in TD. The average frequency in finding the platform decreased in SD rats; however, exercise training improved this parameter in TD rats. Aerobic exercise decreased Tau phosphorylation and APP expression, and increased some proteins related to insulin/IGF‐1 pathway in hippocampus of diabetic rats. Thus, these molecular adaptations from exercise training might contribute to improved spatial learning and memory in diabetic organisms. © 2014 Wiley Periodicals, Inc.     

Mitochondrial function following downhill and/or uphill exercise training in rats

Introduction: The goal of this study was to compare the effects of downhill (DH), uphill (UH), and UH‐DH exercise training, at the same metabolic rate, on exercise capacity and skeletal muscle mitochondrial function. Methods: Thirty‐two Wistar rats were separated into a control and 3 trained groups. The trained groups exercised for 4 weeks, 5 times per week at the same metabolic rate, either in UH, DH, or combined UH‐DH. Twenty‐four hours after the last training session, the soleus, gastrocnemius, and vastus intermedius muscles were removed for assessment of mitochondrial respiration. Results: Exercise training, at the same metabolic rate, improved maximal running speed without specificity for exercise modalities. Maximal fiber respiration was enhanced in soleus and vastus intermedius in the UH group only. Conclusions: Exercise training, performed at the same metabolic rate, improved exercise capacity, but only UH‐trained rats enhanced mitochondrial function in both soleus and vastus intermedius skeletal muscle. Muscle Nerve 54 : 925–935, 2016     

Evaluation of potential synergistic action of a combined treatment with alpha‐methyl‐prednisolone and taurine on the mdx mouse model of Duchenne muscular dystrophy

A. Cozzoli, J.‐F. Rolland, R. F. Capogrosso, V. T. Sblendorio, V. Longo, S. Simonetti, B. Nico and A. De Luca (2011) Neuropathology and Applied Neurobiology 37, 243–256
Evaluation of potential synergistic action of a combined treatment with alpha‐methyl‐prednisolone and taurine on the mdx mouse model of Duchene muscular dystrophy Aims: Glucocorticoids are the sole drugs clinically used in Duchenne muscular dystrophy, in spite of the relevant side effects. Combination of glucocorticoids with synergistic drugs may be one strategy to lower doses and control side effects, meanwhile providing wider control of the complex pathology. This study is a preclinical evaluation of the effect of a combined treatment of α‐methyl‐prednisolone (PDN) with taurine, a safe aminoacid with positive effects on some pathology‐related events. Methods: PDN (1 mg/kg/day i.p.) and taurine (1 g/kg/day orally) were administered either alone or in combination, for 4–8 weeks to male dystrophic mdx mice chronically exercised on a treadmill. Effects were assessed in vivo and ex vivo with a variety of methodological approaches. Results: In vivo, each treatment significantly increased fore limb strength, a marked synergistic effect being observed with the combination PDN + taurine. Ex vivo, PDN + taurine completely restored the mechanical threshold, an electrophysiological index of calcium homeostasis, of extensor digitorum longus myofibres and the benefit was greater than for PDN alone. In parallel, the overactivity of voltage‐independent cation channels in dystrophic myofibres was reduced. No effects were observed on plasma levels of creatine kinase, while lactate dehydrogenase was decreased by taurine and, to a minor extent, by PDN + taurine. A similar histology profile was observed in PDN and PDN + taurine‐treated muscles. PDN + taurine significantly increased taurine level in fast‐twitch muscle and brain, by high‐pressure liquid chromatography analysis. Conclusions: The combination PDN + taurine has additive actions on in vivo and ex vivo functional end points, with less evident advantages on histopathology and biochemical markers of the disease.     

Low‐intensity treadmill exercise‐related changes in the rat stellate ganglion neurons

Stellate ganglion (SG) represents the main sympathetic input to the heart. This study aimed at investigating physical exercise–related changes in the quantitative aspects of SG neurons in treadmill‐exercised Wistar rats. By applying state‐of‐the‐art design‐based stereology, the SG volume, total number of SG neurons, mean perikaryal volume of SG neurons, and the total volume of neurons in the whole SG have been examined. Arterial pressure and heart rate were also measured at the end of the exercise period. The present study showed that a low‐intensity exercise training program caused a 12% decrease in the heart rate of trained rats. In contrast, there were no effects on systolic pressure, diastolic pressure, or mean arterial pressure. As to quantitative changes related to physical exercise, the main findings were a 21% increase in the fractional volume occupied by neurons in the SG, and an 83% increase in the mean perikaryal volume of SG neurons in treadmill‐trained rats, which shows a remarkable neuron hypertrophy. It seems reasonable to infer that neuron hypertrophy may have been the result of a functional overload imposed on the SG neurons by initial posttraining sympathetic activation. From the novel stereological data we provide, further investigations are needed to shed light on the mechanistic aspect of neuron hypertrophy: what role does neuron hypertrophy play? Could neuron hypertrophy be assigned to the functional overload induced by physical exercise? © 2008 Wiley‐Liss, Inc.     

Degeneration of retinal neuronal processes and pigment epithelium in the early stage of the streptozotocin‐diabetic rats

Early pathological and electro‐physiological changes of the retina in the streptozotocin (STZ)‐diabetic rats were investigated through optical and electron microscopy in two strains and electro‐retinography in one strain. In Sprague–Dawley (SD) rats 1 month after the onset of diabetes, the thickness of the inner plexiform layer (IPL) and photoreceptor segment layer (PSL) was significantly reduced by 9.9% and 18.9%, respectively (P < 0.01, P < 0.05). In Brown–Norway (BN) rats STZ‐diabetic for 1 month, the thickness of the IPL was also significantly reduced by 15.7% (P < 0.05). Cytochemical study using peanut agglutinin (PNA), a lectin binding selectively to the cone photoreceptor‐associated domains of the inter‐photoreceptor matrix, revealed a marked reduction in intensity, number and length of the PNA‐binding cone photoreceptors. Electron microscopy showed deepened hollows in the basal infoldings of the retinal pigment epithelium (RPE) of STZ‐rats diabetic for 1 month and large concavities into the cytoplasm in STZ‐rats diabetic for 6 months. Blood vessels in the retina and choroid were unremarkable. Single‐flash electro‐retinogram revealed a reduction in the amplitudes of a‐ and b‐waves of electro‐retinogram (ERG) of 1 month STZ BN rats (P < 0.05). These findings indicate that the degeneration of rods/cones in the PSL and RPE are the most prominent pathological alteration sites in the early stage of diabetic rats.     

Treadmill Exercise Prevents Increase of Neuroinflammation Markers Involved in the Dopaminergic Damage of the 6-OHDA Parkinson’s Disease Model

Parkinson’s disease (PD) involves loss of dopaminergic neurons in the substantia nigra (SN), which can be correlated to neuroinflammatory changes with the aging of the nervous system. On the other hand, exercise can reduce the deleterious effects promoted by age, but the mechanism involved is still unclear. This study investigated the preventive exercise-induced changes on neuroinflammatory processes in a rat model of PD induced by unilateral striatal injections of 6-hydroxydopamine (6-OHDA). Adult male Wistar rats were divided into two groups: (1) sedentary (SED) or (2) exercised (EX), animals that did treadmill exercise three times per week, every other day, for 4 weeks prior to 6-OHDA or saline injection. The rats were then divided into four sub-groups: (1) sedentary saline (SED), (2) sedentary 6-OHDA (SED + 6-OHDA), (3) exercised saline (EX), and (4) exercised 6-OHDA (EX + 6-OHDA). Seven and 30 days after surgery, brains were collected for immunohistochemistry and immunoblotting for dopaminergic and neuroinflammatory markers into SN and striatum. The SED + 6-OHDA animals presented an increase in the astrocyte, microglial, and oxidative species activation. On the other hand, EX + 6-OHDA animals did not present neuroinflammatory responses and performed better apormorphine test. Our data suggest that treadmill exercise throughout life can markedly reduce the chances of dopamine decrease, reinforcing studies that showed a lower incidence of Parkinson’s disease in patients who were active during life.     

An internet‐based physical activity intervention for adolescents with cerebral palsy: a randomized controlled trial

Aim To determine the effectiveness of an 8‐week internet‐based, lifestyle physical‐activity intervention for adolescents with cerebral palsy (CP). Method A randomized controlled trial using concealed allocation with blinded assessments at baseline, 10, and 20 weeks. Forty‐one adolescents with CP participated (26 males, 15 females; mean age 13y 7mo, SD 1y 8mo, range 11–17y; Gross Motor Function Classification System levels: I, n=21; II, n=17; III, n=3; unilateral distribution n=16, bilateral n=25). Primary outcome was physical activity (NL‐1000 accelerometers and self‐report [Multimedia Activity Recall for Children and Adolescents: MARCA]). Secondary outcomes were exercise knowledge (a purpose‐designed scale), attitudes, intention and self‐efficacy (Lifestyle Education for Activity Program II scales), self‐reported sedentary behaviour (MARCA), and functional capacity (6‐min walk test). Results At 10 weeks the intervention group showed no increased physical activity compared with the comparison group (weekly steps: change of +2420 vs ?12189 steps p=0.06; weekly moderate‐to‐vigorous physical activity: change of +70 vs +8min, p=0.06; weekly distance walked: change of +3 vs ?9.1km, p=0.05) and exercise knowledge (12% vs 1% improvement, p=0.08). There were no statistically significant differences for these outcomes at 20 weeks, or in self‐reported physical activity at 10 or 20 weeks. Interpretation There was a positive short‐term pattern for improvement in physical activity and knowledge. Internet‐based programs may offer an alternative for participants unable to attend regular face‐to‐face physical activity programs.     

The effects of strength,aerobic, and concurrent exercise on skeletal muscle damage in rats

Introduction: In this study we examined oxidative stress and skeletal muscle damage resulting from acute strength, aerobic, or concurrent exercise in rats. Methods: The animals were divided into control (C), strength (SE), aerobic (AE), and combined (CE) exercise groups. They were euthanized at 3 different time‐points (6, 24, and 48 h) after acute exercise. Results: SE exercise rats had increased dichlorofluorescein oxidation at 6 h post‐exercise and decreased superoxide dismutase activity at all time‐points. Glutathione peroxidase activity and sulfhydryl levels were increased in the AE group at 48 h post‐exercise. Serum lactate dehydrogenase activity was increased in the SE and CE groups at 24 h and in the AE group at 48 h. Echo intensity was elevated at 24 h for all groups. Conclusions: Forty‐eight hours was sufficient for complete recovery from oxidative stress and muscle damage in the SE and CE groups, but not in the AE group. Muscle Nerve 50 : 79–86, 2014     

Angiogenesis and expression of PDGF‐C,VEGF, CD105 and HIF‐1α in human glioblastoma

Glioblastoma (GBM), the most frequent and aggressive brain tumor, is characterized by marked angiogenesis directly related to invasiveness and poor prognosis. Hypoxia is considered to be an important stimulus for angiogenesis by inducing hypoxia‐inducible factor 1‐alpha (HIF‐1α) overexpression that activates platelet‐derived growth factor (PDGF) and VEGF. The aim of this study is to analyze the expression of PDGF‐C, VEGF in endothelial and tumor cells of GBM and their relation to HIF‐1α expression. Two hundred and eight GBM cases were studied by tissue microarray immunohistochemical preparation. Expression of HIF‐1α, VEGF and PDGF‐C was observed in 184 (88.5%), 131 (63%) and 160 (76.9%) tumor cases, respectively. The numbers of vessels were quantified by CD34, PDGF‐C, VEGF and CD105 staining, and were in median 20, 16, 5 and 6, respectively. The GBMs that showed positive or negative expression for HIF‐1α showed a median vascular density of 30 and 14, respectively, for CD34 (P < 0.015). Positive expression for HIF‐1α was correlated with VEGF and PDGF‐C expression in tumors (P < 0.001). There was a significant correlation between VEGF and PDGF‐C expression in the cytoplasm of GBM tumor cells (P < 0.0001). We showed that VEGF expression in tumor cells was correlated with its expression in blood vessels (P < 0.0001). Endothelial cells with PDGF‐C and VEGF positive expression were also positive for CD105 and their nuclei for Ki‐67, confirming the neoangiogenic and proliferative influence of VEGF and PDGF‐C. VEGF nuclear staining in tumor cells (P = 0.002) as well as nuclear staining for HIF‐1α and VEGF (P = 0.005) correlated with survival. In summary, our present findings of the concomitant upregulation of PDGF‐C with VEGF in GBM tumor cells and vessels further reinforce the benefit of using combined anti‐angiogenic approaches to potentially improve the therapeutic response for GBM.     

Physical (in)activity‐dependent structural plasticity in bulbospinal catecholaminergic neurons of rat rostral ventrolateral medulla

Increased activity of the sympathetic nervous system is thought to play a role in the development and progression of cardiovascular disease. Recent work has shown that physical inactivity versus activity alters neuronal structure in brain regions associated with cardiovascular regulation. Our physiological studies suggest that neurons in the rostral ventrolateral medulla (RVLM) are more responsive to excitation in sedentary versus physically active animals. We hypothesized that enhanced functional responses in the RVLM may be due, in part, to changes in the structure of RVLM neurons that control sympathetic activity. We used retrograde tracing and immunohistochemistry for tyrosine hydroxylase (TH) to identify bulbospinal catecholaminergic (C1) neurons in sedentary and active rats after chronic voluntary wheel‐running exercise. We then digitally reconstructed their cell bodies and dendrites at different rostrocaudal levels. The dendritic arbors of spinally projecting TH neurons from sedentary rats were more branched than those of physically active rats (P < 0.05). In sedentary rats, dendritic branching was greater in more rostral versus more caudal bulbospinal C1 neurons, whereas, in physically active rats, dendritic branching was consistent throughout the RVLM. In contrast, cell body size and the number of primary dendrites did not differ between active and inactive animals. We suggest that these structural changes provide an anatomical underpinning for the functional differences observed in our in vivo studies. These inactivity‐related structural and functional changes may enhance the overall sensitivity of RVLM neurons to excitatory stimuli and contribute to an increased risk of cardiovascular disease in sedentary individuals. J. Comp. Neurol. 522:499–513, 2014. © 2013 Wiley Periodicals, Inc.     

Cerebral angiogenesis and expression of angiogenic factors in aging rats after exercise

The effect that exercise has on angiogenesis in the aging rat is unknown. We initiated this study with the intent to determine if exercise could induce angiogenesis in aging rats, as well as in adult rats reported previously. The markers we used to determine our endpoint were vascular endothelial growth factor (VEGF) and angiopoietin 1 and 2, as well as vascular density. Aged (22 month old) female Fisher 344 rats (n=16) were exercised on a treadmill 30 minutes each day for 3 weeks, or housed as non-exercised controls for the same duration. At the end of the exercise protocol, a significant (p<0.01) increase in the density of microvessels was found within the cerebral vasculature of the rats. Exercise was also associated with a significantly (p<0.01) increased mRNA expression of angiopoietin 1 and 2 in the aged cohort of rats. A mild but significant (p<0.01) increase in the four isoforms of VEGF mRNA (120, 144, 164, 188) were observed, with VEGF120 and VEGF144 being more markedly up-regulated than the other two. VEGF protein expression was also significantly (p<0.01) increased. This study demonstrates that angiogenesis can be induced in aging rats via exercise. The induced angiogenesis was associated with overexpression of angiogenic factors. These results support the hypothesis that an angiogenic response to chronic physical exercise is maintained with aging.