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Reperfusion is the fundamental treatment for ischaemic stroke; however, many ischaemic stroke patients cannot undergo reperfusion treatment. Furthermore, reperfusion can cause ischaemic reperfusion injuries. This study aimed to determine the effects of reperfusion in an in vitro ischaemic stroke model—oxygen and glucose deprivation (OGD) (0.3% O2)—with rat pheochromocytoma (PC12) cells and cortical neurons. In PC12 cells, OGD resulted in a time-dependent increase in cytotoxicity and apoptosis, and reduction in MTT activity from 2 h onwards. Reperfusion following shorter periods (4 and 6 h) of OGD recovered apoptotic PC12 cells, whereas after 12 h, OGD increased LDH release. In primary neurons, 6 h OGD led to significant increase in cytotoxicity, reduction in MTT activity and dendritic MAP2 staining. Reperfusion following 6 h OGD increased the cytotoxicity. HIF-1a was stabilised by 4 and 6 h OGD in PC12 cells and 2 h OGD onwards in primary neurons. A panel of hypoxic genes were upregulated by the OGD treatments depending on the duration. In conclusion, the duration of OGD determines the mitochondrial activity, cell viability, HIF-1a stabilization, and hypoxic gene expression in both cell types. Reperfusion following OGD of short duration is neuroprotective, whereas OGD of long duration is cytotoxic.

Knee pain is commonly seen in orthopedic and rehabilitation outpatient clinical settings, and in the aging population. Bursitis of the knee joint, especially when the volume of the synovial fluid is large enough, can compress and distend the nearby soft tissues, causing pain in the knee joint. Out of all the bursae surrounding the knee joint, supra-patellar bursitis is most often associated with knee pain. Treatment strategies in managing supra-patellar bursitis include the aspiration of joint synovial fluid and then followed by steroid injection into the bursa. When supra-patellar bursitis is caused by degenerative disorders, the concept of viscosupplementation treatment may be effective by injecting hyaluronic acid into the bursa. However, the rheology or the changes in the concentrations of proteins (biomarkers) that are related to the development of bursitis in the synovial fluid is virtually unexplored. Therefore, this study aimed to identify the concentration changes in the synovial fluid total protein amount and individual proteins associated with supra-patellar bursitis using the Bradford protein assay and western immunoglobulin methods. A total of 20 patients were divided into two groups with 10 patients in each group. One group received the high molecular weight hyaluronic acid product of Synvisc Hylan G-F 20 and the other group received the low molecular weight hyaluronic acid product of Hya-Joint Synovial Fluid Supplement once per week injection into the bursa for a total of 3weeks. Significant decreases in the synovial fluid total protein concentrations were observed after the second dosage of high molecular weight hyaluronic acid injections. Apolipoprotein A-I, interleukin 1 beta, alpha 1 antitrypsin, and matrix metalloproteinase 1 proteins revealed a trend of decreasing western immunoblotting band densities after hyaluronic acid injections. The decreases in apolipoprotein A-I and interleukin 1 beta protein band densities were significant in the high molecular weight hyaluronic acid injection group. Transthyretin, complement 5, and matrilin 3 proteins revealed a trend of increasing western immunoblotting band densities after hyaluronic acid injections. Transthyretin revealed significant increases in protein band densities in both the high and low molecular weight hyaluronic acid injection groups. This study may provide the rationale for targeting several biomarkers associated with lipid transport, inflammation, and anti-aging as possible disease modifying therapies for the treatment of supra-patellar bursitis and even degenerative joint disorders.

Previous attempts to identify neuroprotective targets by studying the ischemic cascade and devising ways to suppress it have failed to translate to efficacious therapies for acute ischemic stroke. We hypothesized that studying the molecular determinants of endogenous neuroprotection in two well-established paradigms, the resistance of CA3 hippocampal neurons to global ischemia and the tolerance conferred by ischemic preconditioning (IPC), would reveal new neuroprotective targets. We found that the product of the tuberous sclerosis complex 1 gene (TSC1), hamartin, is selectively induced by ischemia in hippocampal CA3 neurons. In CA1 neurons, hamartin was unaffected by ischemia but was upregulated by IPC preceding ischemia, which protects the otherwise vulnerable CA1 cells. Suppression of hamartin expression with TSC1 shRNA viral vectors both in vitro and in vivo increased the vulnerability of neurons to cell death following oxygen glucose deprivation (OGD) and ischemia. In vivo, suppression of TSC1 expression increased locomotor activity and decreased habituation in a hippocampal-dependent task. Overexpression of hamartin increased resistance to OGD by inducing productive autophagy through an mTORC1-dependent mechanism. Copyright © 2013 Nature America, Inc.

This study investigated the function of each of the hypoxia inducible factor (HIF) prolyl-4-hydroxylase enzymes (PHD1–3) in the first 24 h following transient focal cerebral ischaemia by using mice with each isoform genetically suppressed. Male, 8- to 12-week old PHD1−/−, PHD2+/− and PHD3−/− mice and their wild-type (WT) littermate were subjected to 45 min of middle cerebral artery occlusion (MCAO). During the experiments, regional cerebral blood flow (rCBF) was recorded by laser Doppler flowmetry. Behaviour was assessed at both 2 h and 24 h after reperfusion with a common neuroscore. Infarct volumes, blood–brain barrier (BBB) disruption, cerebral vascular density, apoptosis, reactive oxygen species (ROS), HIF1α, and glycogen levels were then determined using histological and immunohistochemical techniques. When compared to their WT littermates, PHD2+/− mice had significantly increased cerebral microvascular density and more effective restoration of CBF upon reperfusion. PHD2+/− mice showed significantly better functional outcomes and higher activity rates at both 2 h and 24 h after MCAO, associated with significant fewer apoptotic cells in the penumbra and less BBB disruption; PHD3−/− mice had impaired rCBF upon early reperfusion but comparable functional outcomes; PHD1−/− mice did not show any significant changes following the MCAO. Production of ROS, HIF1α staining and glycogen content in the brain were not different in any comparison. Life-long genetic inhibition of PHD enzymes produces different effects on outcome in the first 24 h after transient cerebral ischaemia. These need to be considered in optimizing therapeutic effects of PHD inhibitors, particularly when isoform specific inhibitors become available.

Studies have shown that ageing alone can cause increases in the concentrations of many cerebrospinal fluid (CSF) proteins. Therefore, CSF protein concentrations must be interpreted with caution before concluding that the increased concentrations of certain proteins can be used as disease-specific biomarkers. Age-related reduction in CSF turnover has been shown to have a significant concentrating effect on CSF proteins from young to old. As a result, CSF protein concentrations need to be corrected with age-specific turnovers first before performing any data comparisons between different ages. This study applied the concept of CSF/plasma concentration ratios of plasma-derived proteins that is frequently used in the investigation of brain barrier integrity to calculate the amount of protein that enters the CSF from the plasma side in different age groups. Based on our calculations, proteins with molecular weights greater than 91.92 kDa for the young, 109.51 kDa for the middle-aged and 120 kDa for the old should not be able to cross the brain barriers of the blood-brain and blood-CSF barriers to enter the CSF from the plasma side. For proteins that can be derived from the choroid plexus (CP), brain, and plasma, the amount that crosses the barriers to enter the CSF from the plasma side will contribute to their measured total protein concentrations in the CSF. CP and brain production of these proteins can be calculated when turnover corrected CSF protein concentrations are further corrected by the amount of protein that crosses the barriers. In this study, CP and brain produced concentrations of transthyretin, retinol binding protein, alpha-1-antitrypsin, gelsolin, and lactotransferrin were calculated. The production of these proteins decreased with age with alpha-1-antitrypsin protein revealing the most substantial decrease of 86% from young (0.14±0.01 mg·dL(-1)) to old (0.02 mg·dL(-1)). In conclusion, measured CSF protein concentrations for proteins that can be derived from the CP, brain, and plasma need to be corrected by age-specific CSF turnovers and by the amount of protein that crosses the brain barriers first before their concentrations can be compared logically between different ages.

The best neuroprotectant for acute ischaemic stroke would always be the rapid return of oxygen and glucose to physiological levels. This is currently provided by thrombolysis which restores blood flow to the ischaemic region. The attempt to confer neuroprotection by targeting the brain parenchyma has shown promise in experimental stroke models, but has unequivocally failed to translate to the clinic. Neuroprotective therapy primarily targets the biochemical cascade that produces cell death following cerebral ischaemia. However, these agents may also alter signal transduction that controls cerebral blood flow, for example glutamate, which may affect the outcome after ischaemia. In these cases, neuroprotection may potentially be due to the improved access to oxygen and glucose rather than biochemical prevention of cell death. Improvement in cerebral blood flow is an important but often overlooked effect of neuroprotective therapy, analogous to the protective effects of drug-induced hypothermia. This short review will discuss cerebral blood flow alteration and protection of the brain in the context of ischaemic preconditioning, oxygen sensing and thrombolysis. Future neuroprotection studies in cerebral ischaemia require stringent monitoring of cerebral blood flow, plus other physiological parameters. This will increase the chances that any protection observed may be able to translate to human therapy.

Studies have shown that ageing and several neurological diseases of the central nervous system are often accompanied with increase in concentrations of many cerebrospinal fluid (CSF) proteins. However, few studies have actually looked into the mechanisms behind the increase in CSF protein concentrations. In this study, CSF secretion rates and turnovers were measured using the in situ perfused choroid plexus (CP) technique in a group of sheep between 1 and 10 years of age. CSF protein concentrations were determined using quantitative proteomic techniques. CSF turnover in hours correlated significantly with age, changing from 10.5+/-2.7h in the young to 17.1+/-2.4h in the old. The amount of CSF replaced per hour decreased from 2.46+/-0.42mL in the young to 1.17+/-0.16mL in the old. The age-related reduction in CSF turnover was calculated to have a concentrating effect of approximately 1.32 times in middle-aged and 2.10 times in old CSF proteins. After CSF turnover normalization, CSF albumin (a plasma-derived protein) concentration still increased significantly with age; however, both brain-derived and partially brain-derived protein concentrations in the CSF decreased with age after normalization. Regression analysis between turnovers and albumin concentrations has shown that reduced CSF turnover was the cause of increased CSF albumin concentrations with age. Therefore, CSF protein concentrations should be normalized according to their age-specific turnovers first before their concentrations can be compared logically between different ages.

Dysfunction of the choroid plexuses (CPs) and the blood-cerebrospinal fluid barrier (BCSFB) might contribute to age-related cognitive decline and neurodegenerative disease. We used the CPs from young (1-2 years), middle-aged (3-6 years) and old (7-10 years) sheep to explore effects of aging on various aspects of CP and BCSFB functions. Total protein in the cerebrospinal fluid (CSF) was significantly higher in old compared to young sheep and CSF secretion by the CP perfused in situ was significantly lower in both old and middle-aged when compared to young sheep, which correlated with reduced (22)Na(+) uptake and efflux by the CP. Steady-state extractions of a low and medium size molecular weight extracellular space marker, (14)C-mannitol and (3)H-polyethylene glycol, respectively, were significantly higher in CPs from old compared to young animals; however, there was no significant difference in steady-state extraction of a high molecular weight marker, (125)I-bovine serum albumin. This indicates increased passive BCSFB permeability for small and medium sized molecules in old sheep. CP redox activity was significantly lower in the old animals as assessed by the MTT assay, however, there was no significant difference in ATP content and energy charge of the CP with age suggesting adequate baseline energy reserve capacity. These data indicate that normal aging processes alter protein content in the CSF, CSF secretion, integrity of the BCSFB and Na(+) flux in the epithelial layer, which could impact on CSF homeostasis and turnover.

The knowledge of brain syndromes is essential for stroke physicians and neurologists, particularly those that can be extremely difficult and challenging to diagnose due to the great variability of symptom presentation and yet of clinical significance in terms of potential devastating effect with poor outcome. The diagnosis and understanding of stroke syndromes has improved dramatically over the years with the advent of modern imaging, while the management is similar to general care as recommended by various guidelines in addition to care of such patients on specialized units with facilities for continuous monitoring of vital signs and dedicated stroke therapy. Such critical care can be provided either in the acute stroke unit, the medical intensive care unit or the neurological intensive care unit. There may be no definitive treatment at reversing stroke syndromes, but it is important to identify the signs and symptoms for an early diagnosis to prompt quick treatment, which can prevent further devastating complications following stroke. The aim of this article is to discuss some of the important clinical stroke syndromes encountered in clinical practice and discuss their management.