The Korean hip fracture registry study.

BACKGROUND: The purpose of the Korean Hip Fracture Registry (KHFR) Study is to establish a nationwide, hospital-based prospective cohort study of adults with hip fracture to explore the incidence and risk factors of second osteoporotic fractures for a Fracture Liaison Service (FLS) model. METHODS: The KHFR, a prospective multicenter longitudinal study, was launched in 2014. Sixteen centers recruited participants who were treated for hip fracture. The inclusion criteria were patients, who were treated for proximal femur fracture due to low-energy trauma and aged 50 or more at the time of injury. Until 2018, 5,841 patients were enrolled in this study. Follow-up surveys were conducted annually to determine occurrence of second osteoporotic fracture, and 4,803 participants completed at least one follow-up survey. DISCUSSION: KHFR is a unique resource of individual level on osteoporotic hip fracture with radiological, medical, and laboratory information including DXA (dual energy x-ray absorptiometry), bone turnover marker, body composition, and hand grip strength for future analyses for FLS model. Modifiable factors for mortality after hip surgery is planned to be identified with nutritional assessment and multi-disciplinary interventions from hospitalization to follow-ups. The proportions of femoral neck, intertrochanteric, and subtrochanteric fractures were 517 (42.0%), 730 (53.6%), and 60 (4.4%), respectively, from 2014 to 2016, which was similar in other studies. Radiologic definition of atypical subtrochanteric fracture was adopted and 17 (1.2%) fractures among 1,361 proximal femoral fractures were identified. Internal fixation showed higher reoperation rate compared to arthroplasty in unstable intertrochanteric fractures (6.1% vs. 2.4%, p = 0.046) with no significant difference in mortality. The KHFR plans to identify outcomes and risk factors associated with second fracture by conducting a 10-year cohort study, with a follow-up every year, using 5,841 baseline participants. TRIAL REGISTRATION: Present study was registered on Internet-based Clinical Research and Trial management system (iCReaT) as multicenter prospective observational cohort study (Project number: C160022, Date of registration: 22th, Apr, 2016).

Microvascular Reactivity Measured by Dynamic Near-infrared Spectroscopy Following Induction of General Anesthesia in Healthy Patients: Observation of Age-related Change.

Background: The purpose of this study was to investigate the effect of general anesthesia on microvascular reactivity and tissue oxygen saturation (StO2) using near-infrared spectroscopy in conjunction with vascular occlusion tests (VOT). Age-related changes of microvascular reactivity, that is, the capacity of capillary recruitment, were examined. Methods: This prospective observational study was performed on 60 patients without comorbidities who underwent elective surgery under general anesthesia. Baseline StO2 on thenar eminence, hemodynamics, and laboratory profile were monitored before (T0) and 30 min after general anesthesia (T1). During VOT, occlusion slope representing oxygen consumption of muscle and recovery slope representing microvascular reactivity were also collected at T0 and T1. Results: Baseline StO2 and minimum / maximum StO2 during VOT increased under general anesthesia. Occlusion slope decreased while the recovery slope increased under general anesthesia. To observe aging effect, Receiver operating characteristic analysis was performed and age less than 65 years old showed a fair performance in predicting the increase of microvascular reactivity after the induction of anesthesia (AUC 0.733, 95% CI 0.594-0.845, P= 0.003). For age-related analyses, 27 patients of younger group (< 65 years) and 26 patients of older group (≥ 65 years) were divided. Recovery slope significantly increased under general anesthesia in younger group (2.44 [1.91-2.81] % ∙ sec-1 at T0 and 3.59 [2.58-3.51] % ∙ sec-1 at T1, P <0.001), but not in older group (2.61 [2.21-3.20] % ∙ sec-1 at T0, 2.63 [1.90-3.60] % ∙ sec-1 at T1, P = 0.949). Conclusions: General anesthesia could improve StO2 through increase of microvascular reactivity and decrease of tissue metabolism. However, microvascular reactivity to capillary recruitment under general anesthesia significantly improves in younger patients, not in older patients.

Osteonecrosis of the Femoral Head: an Updated Review of ARCO on Pathogenesis, Staging and Treatment.

Non-traumatic osteonecrosis of the femoral head (ONFH) usually affects adults younger than 50 years and frequently leads to femoral head collapse and subsequent arthritis of the hip. It is becoming more prevalent along with increasing use of corticosteroids for the adjuvant therapy of leukemia and other myelogenous diseases as well as management of organ transplantation. This review updated knowledge on the pathogenesis, classification criteria, staging system, and treatment of ONFH.

Diagnosis and Treatment of Femoral Head Osteonecrosis: A Protocol for Development of Evidence-Based Clinical Practice Guidelines.

INTRODUCTION: There are many treatment options for patients who have osteonecrosis of the femoral head (ONFH) and management strategies vary widely both among and within individual countries. Although many researchers have attempted to elucidate the optimal strategies for managing this disease, the lack of large-scale randomized control trials and the lack of agreement on disease staging have curtailed the development of clear-cut guidelines. MATERIALS AND METHODS: The Association Research Circulation Osseous (ARCO) group sought to address three questions for the management of patients who have ONFH: 1) What imaging studies are most sensitive and specific for the diagnostic evaluation of patients who have ONFH?; 2) What is the best treatment strategy for preventing disease progression in patients who have pre-collapse lesions?; and 3) What is the best treatment strategy for patients who have post-collapse disease? The Patient, Intervention, Comparison, and Outcome (PICO) format was used to formulate the search strategy for each research question. A systematic review will be performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. ARCO participants have been allocated to three groups, each representing one of the PICO questions. After qualitative and quantitative analysis of the data extracted from studies pertaining to each of the three research questions, a set of evidence-based clinical practice guidelines will be proposed for the management of patients who have ONFH. DISCUSSION: It is not always clear which treatment method is optimal for the management of ONFH. Thus, many surgeons have developed and performed various procedures based on patient-specific factors. As there is no consensus on the optimal treatment for various stages of disease, it was clear that developing evidence-based clinical practice guidelines would provide more structure and uniformity to management of these patients. Therefore, the results of this systematic review will lead to the development guidelines that may improve patient-care strategies and result in better outcomes for patients who have ONFH.

Discharge transition experienced by older Korean women after hip fracture surgery: a qualitative study.

BACKGROUND: This study aimed to explore older Korean women's discharge transition experiences after hip fracture surgery. METHODS: This was a descriptive qualitative study. Face-to-face interviews following hip fracture surgery were conducted on 12 women aged 65-87 years. Data were collected 1 to 2 days before discharge and again 4 weeks after discharge following hip fracture surgery, and were analyzed using qualitative content analysis. RESULTS: Four main themes were identified: (1) challenge of discharge transition: unprepared discharge, transfer into other care settings, and eagerness for recovery; (2) physical and psychological distress against recovery: frail physical state and psychological difficulties; (3) dependent compliance: absolute trust in healthcare providers, indispensable support from the family, and passive participation in care; and (4) walking for things they took for granted: hope of walking and poor walking ability. CONCLUSIONS: After their hip fracture surgeries, older women hoped to be able to walk and perform simple daily chores they previously took for granted. Considering the physical and psychological frailty of older women undergoing hip surgery, systematic nursing interventions including collaboration and coordination with other healthcare professionals and settings are necessary to ensure the quality of continuous care during their post-surgery discharge transition. Encouraging partial weight bearing and initiating intervention to reduce fear of falling at the earliest possible time are essential to attain a stable discharge transition. Additionally, older women should be invited to participate in their care, and family involvement should be encouraged during the discharge transition period in South Korea.

Role of Sevoflurane on Natural Killer Group 2, Member D-Mediated Immune Response in Non-Small-Cell Lung Cancer: An In Vitro Study.

BACKGROUND The purpose of this study was to investigate the effects of sevoflurane on cancer immunosurveillance and metastasis in non-small-cell lung cancer (NSCLC). MATERIAL AND METHODS NCI-H23 cells, a human NSCLC cell line, were incubated with or without sevoflurane at the concentrations of 0, 12.5, 25, 50, 100, and 200 µM for 6 h. Cell viability, the expression of natural killer group 2, member D ligands (NKG2D ligands: UL16-binding proteins 1-3 [ULBP1-3] and major histocompatibility complex class I chain-related molecules A/B [MICA/B]), the expression of matrix metalloproteinases (MMPs), NK cell-mediated cytotoxicity, and cancer cell migration were measured. RESULTS At 12.5, 25, 50, and 100 µM, sevoflurane increased the expression of NKG2D ligands (ULBP2-3 and MICA, ULBP1-3, ULBP1-3, and ULBP1, respectively). Sevoflurane decreased the expression of NKG2D ligands at 200 µM (MICA/B). NK cell-mediated lysis of NCI-H23 cells at 200 µM sevoflurane was significantly reduced compared with the control (P=0.025; target cell: effect cell=1: 10). Sevoflurane increased the expression of MMP-1, -2, and -9 and increased cell migration in NCI-H23 cells at 50, 100, and 200 µM (P=0.001, 0.035, and 0.039, respectively, compared with the control after 18 h of wound formation). CONCLUSIONS Sevoflurane could suppress NKG2D-mediated NK cell cytotoxicity and increased expression of MMPs and migration in NCI-H23 cells. Further research is needed to determine the effects of sevoflurane on cancer immunosurveillance and metastasis in NSCLC.

Comparative Cerebroprotective Potential of d- and l-Carnosine Following Ischemic Stroke in Mice.

l-carnosine is an attractive therapeutic agent for acute ischemic stroke based on its robust preclinical cerebroprotective properties and wide therapeutic time window. However, large doses are needed for efficacy because carnosine is rapidly degraded in serum by carnosinases. The need for large doses could be particularly problematic when translating to human studies, as humans have much higher levels of serum carnosinases. We hypothesized that d-carnosine, which is not a substrate for carnosinases, may have a better pharmacological profile and may be more efficacious at lower doses than l-carnosine. To test our hypothesis, we explored the comparative pharmacokinetics and neuroprotective properties of d- and L-carnosine in acute ischaemic stroke in mice. We initially investigated the pharmacokinetics of d- and L-carnosine in serum and brain after intravenous (IV) injection in mice. We then investigated the comparative efficacy of d- and l-carnosine in a mouse model of transient focal cerebral ischemia followed by in vitro testing against excitotoxicity and free radical generation using primary neuronal cultures. The pharmacokinetics of d- and l-carnosine were similar in serum and brain after IV injection in mice. Both d- and l-carnosine exhibited similar efficacy against mouse focal cerebral ischemia. In vitro studies in neurons showed protection against excitotoxicity and the accumulation of free radicals. d- and l-carnosine exhibit similar pharmacokinetics and have similar efficacy against experimental stroke in mice. Since humans have far higher levels of carnosinases, d-carnosine may have more favorable pharmacokinetics in future human studies.

The effect of desflurane on retinal angiogenesis in a mouse model of oxygen-induced retinopathy.

PURPOSE: Retinopathy of prematurity (ROP) is an ocular disorder that primarily occurs in premature infants and is the most common cause of vision impairment. This study examined the effect of desflurane on angiogenesis in a mouse model of oxygen-induced retinopathy (OIR). METHODS: Mice were randomly allocated to the control (C), ROP control (Rc), or ROP with desflurane exposure (Rd) group. To induce ROP, 7-day-old mice were exposed to 75% oxygen in a chamber for 5 days [postnatal days (P) 7-12], and thereafter returned to room air. Age-matched mice exposed to room air formed the C group. The Rd group was exposed to 8% desflurane for 2 h on P12, P13, and P14 with 40% oxygen. To observe changes in angiogenesis of the retina, mice were sacrificed at P16. RESULTS: The ratio of avascular area/total retinal area was not changed significantly in the Rd group, compared to the Rc group. The expression of endothelial growth factor A (VEGF-A) and hypoxia inducible factor-1α (HIF-1α) in the Rd group and Rc group was not significantly different. CONCLUSIONS: Desflurane does not have a significant influence on retinal angiogenesis via HIF-1α and VEGF-A expression in the OIR mouse model. However, these findings are not directly applicable to premature infants, and it is thus necessary to perform further studies to determine the effect of desflurane on angiogenesis.

Inhibitory Effects of a Novel Chrysin-Derivative, CPD 6, on Acute and Chronic Skin Inflammation.

The skin is an important physiological barrier against external stimuli, such as ultraviolet radiation (UV), xenobiotics, and bacteria. Dermal inflammatory reactions are associated with various skin disorders, including chemical-induced irritation and atopic dermatitis. Modulation of skin inflammatory response is a therapeutic strategy for skin diseases. Here, we synthesized chrysin-derivatives and identified the most potent derivative of Compound 6 (CPD 6). We evaluated its anti-inflammatory effects in vitro cells of macrophages and keratinocytes, and in vivo dermatitis mouse models. In murine macrophages stimulated by lipopolysaccharide (LPS), CPD 6 significantly attenuated the release of inflammatory mediators such as nitric oxide (NO) (IC50 for NO inhibition: 3.613 µM) and other cytokines. In cultured human keratinocytes, CPD 6 significantly attenuated the release of inflammatory cytokines induced by the combination of IFN-γ and TNF-α, UV irradiation, or chemical irritant stimulation. CPD 6 inhibited NFκB and JAK2/STAT1 signaling pathways, and activated Nrf2/HO-1 signaling. In vivo relevancy of anti-inflammatory effects of CPD 6 was observed in acute and chronic skin inflammation models in mice. CPD 6 showed significant anti-inflammatory properties both in vitro cells and in vivo dermatitis animal models, mediated by the inhibition of the NFκB and JAK2-STAT1 pathways and activation of Nrf2/HO-1 signaling. We propose that the novel chrysin-derivative CPD 6 may be a potential therapeutic agent for skin inflammation.

Total Synthesis and Biological Evaluation of Sericetin for Protection against Cisplatin-Induced Acute Kidney Injury.

A concise synthesis of sericetin (1) was performed in four steps from readily available 3- O-benzylgalangin (4), featuring electrocyclization to produce the tricyclic core and a sequential aromatic Claisen/Cope rearrangement to incorporate the 8-prenyl group of 1. In addition, the therapeutic potential of sericetin (1), isosericetin (2), and three prenylated tetracyclic synthetic intermediates (11, 12, and 14) against cisplatin-induced nephrotoxicity using renal tubular cells were evaluated. Compound 14 showed therapeutic potential against cisplatin-induced kidney damage.

Imbalanced bone turnover markers and low bone mineral density in patients with osteonecrosis of the femoral head.

PURPOSE: There have been few studies investigating the cumulative effect of individual factors related to bone metabolism on the systemic balance between bone formation and resorption in patients with osteonecrosis of the femoral head (ONFH). We investigated bone mineral density (BMD) of lumbar spine and bone turnover markers that reflect systemic bone metabolism. METHODS: Two-hundred twenty patients with ONFH were matched to 220 healthy subjects according to age, gender, and body mass index. ONFH patients were divided into steroid-induced (18%), alcoholic (21%), and idiopathic ONFH (61%) and subgroup analysis was performed to exclude the effect of steroid and malnutrition on bone metabolism. We compared lumbar spine bone mineral density (BMD) between groups and measured serum bone-specific alkaline phosphatase (BALP) and urinary deoxypyridinoline/creatinine (Dpd/Cr) ratio. RESULTS: Logistic regression analysis revealed low spine BMD was significantly associated with each subgroup of ONFH when compared with that of the control group (odds ratio of 2.27, 4.24, and 1.86 in alcoholic, steroid, and idiopathic ONFH, respectively). The mean value of serum BALP (27.02 U/L) was within the normal reference range while average urine Dpd/Cr ratio (6.24 nM/mM) increased in ONFH group when compared with respective reference range. CONCLUSION: Spine BMD decreased and urinary Dpd/Cr ratio increased in patients with non-traumatic ONFH. Further studies will be necessary to identify whether non-traumatic ONFH is merely a regional disease confined to the femoral head or may affect systemic bone metabolism.

The effect of sevoflurane on retinal angiogenesis in a mouse model of oxygen-induced retinopathy.

BACKGROUND: Sevoflurane is commonly used in general anesthesia for premature neonates. The main mechanism of retinopathy of prematurity (ROP) is increased levels of vascular endothelial growth factor (VEGF). For the investigation of sevoflurane's effect on angiogenesis, the angiogenesis and VEGF expression in the retina were measured after administering sevoflurane in an oxygen-induced retinopathy mice model. MATERIALS AND METHODS: The mice were divided into the normoxic group (Nc and Ns group; n = 6) and the ROP group (C, Rc, and Rs group; n = 6). Rc group were exposed to 75% oxygen for 5 days beginning on postnatal day (P) 7, and then returned to room air. Age-matched mice in the C group were exposed to room air. To observe angiogenesis of the retina, the mice were sacrificed on P16. The Rs group was exposed to 2 vol% sevoflurane for 2 h on P12, P13, and P14 with 40% oxygen. RESULTS: The angiogenic area and the spreading distance of vessels on P4 were statistically decreased in the Ns group, compared to the Nc group. The avascular area on P16 was significantly increased and the expression of VEGF was suppressed in the Rs group compared to the Rc group. CONCLUSIONS: Sevoflurane can inhibit retinal angiogenesis via suppressing VEGF expression in an OIR mice model with exposure to relative hypoxia. Nevertheless, it is still difficult to apply the results of this study immediately to humans because of the heterogeneity of responses to sevoflurane.

A newly synthesized macakurzin C-derivative attenuates acute and chronic skin inflammation: The Nrf2/heme oxygenase signaling as a potential target.

Impaired immune responses in skin play a pivotal role in the development and progression of chemical-associated inflammatory skin disorders. In this study, we synthesized new flavonoid derivatives from macakurzin C, and identified in vitro and in vivo efficacy of a potent anti-inflammatory flavonoid, Compound 14 (CPD 14), with its underlying mechanisms. In lipopolysaccharide (LPS)-stimulated murine macrophages and IFN-γ/TNF-α-stimulated human keratinocytes, CPD 14 significantly inhibited the release of inflammatory mediators including nitric oxide (NO), prostaglandins, and cytokines (IC50 for NO inhibition in macrophages: 4.61µM). Attenuated NF-κB signaling and activated Nrf2/HO-1 pathway were responsible for the anti-inflammatory effects of CPD 14. The in vivo relevance was examined in phorbol 12-myristate 13-acetate (TPA)-induced acute skin inflammation and oxazolone-induced atopic dermatitis models. Topically applied CPD 14 significantly protected both irritation- and sensitization-associated skin inflammation by suppressing the expression of inflammatory mediators. In summary, we demonstrated that a newly synthesized flavonoid, CPD 14, has potent inhibitory effects on skin inflammation, suggesting it is a potential therapeutic candidate to treat skin disorders associated with excessive inflammation.

Autophagy sustains the survival of human pancreatic cancer PANC-1 cells under extreme nutrient deprivation conditions.

Pancreatic ductal adenocarcinomas are an extremely aggressive and devastating type of cancer with high mortality. Given the dense stroma and poor vascularization, accessibility to nutrients is limited in the tumor microenvironment. Here, we aimed to elucidate the role of autophagy in promoting the survival of human pancreatic cancer PANC-1 cells exposed to nutrient-deprived media (NDM) lacking glucose, amino acids, and serum. NDM inhibited Akt activity and phosphorylation of p70 S6K, and induced AMPK activation and mitochondrial depolarization. NDM also time-dependently increased LC3-II accumulation, number of GFP-LC3 puncta, and colocalization between GFP-LC3 and lysosomes. These results suggested that autophagy was progressively activated through Akt- and AMPK-mTOR pathway in nutrient-deficient PANC-1 cells. Autophagy inhibitors (chloroquine and wortmannin) or silencing of Atg5 augmented PANC-1 cell death in NDM. In cells exposed to NDM, chloroquine and wortmannin induced apoptosis and Z-VAD-fmk inhibited cytotoxicity of these inhibitors. These data demonstrate that autophagy is anti-apoptotic and sustains the survival of PANC-1 cells following extreme nutrient deprivation. Autophagy modulation may be a viable therapeutic option for cancer cells located in the core of solid tumors with a nutrient-deficient microenvironment.

Do alumina matrix composite bearings decrease hip noises and bearing fractures at a minimum of 5 years after THA?

BACKGROUND: Ceramic-on-ceramic bearing couples are theoretically attractive in total hip arthroplasty (THA) because of low wear, but concerns regarding ceramic fracture and squeaking have arisen. Improved material properties of newer alumina matrix composite (AMC) materials, known as Delta ceramics, may reduce these risks. In addition, the use of thinner liners and larger femoral heads may be helpful clinically to lower the rate of dislocation. However, limited short-term clinical results are available and intermediate-term effects are unclear. QUESTIONS/PURPOSES: (1) What is the frequency of bearing-related complications (dissociation, fracture, and noise) with ceramic-on-ceramic AMC bearings in cementless THA? (2) What other complications arose in patients treated with these bearings? (3) What are the Harris hip scores (HHS) and survivorship free from reoperation and revision at a minimum of 5 years after cementless THA performed with AMC bearings? METHODS: Over a 9-month period in 2009, one surgeon performed 125 THAs, of which 100 (80% of the total) were performed with cementless, AMC bearings. During the period in question, the exclusion criteria for this implant were primary THAs with severe acetabular or femoral bone defect and revision THAs. Of these, 94 hips (95%) in 91 patients were available for analysis at a minimum of 5 years (range, 5-6 years), because five patients (six hips) had died. Mean age at the time of arthroplasty was 55 ± 14 years. Prostheses with an identical design and Biolox(®) Delta ceramics were used in all patients. Noise was classified into squeaking, clicking, grinding, and popping. Ceramic fracture, dislocation, and any other complications associated with the use of AMC ceramics were also investigated. Clinical evaluation included the modified HHS preoperatively and at each followup. Survivorship free from reoperation and revision was calculated using the Kaplan-Meier method. RESULTS: Of 91 patients, four developed bearing-related complications, including one with liner dissociation despite initial square seating and three with clicking. No patients had ceramic fractures. A single event of perioperative dislocation occurred in one patient and postoperative periprosthetic fracture occurred in two hips. Mean HHS improved from 56 to 93 points at the final followup (p < 0.001). Survivorship at 5 years free from reoperation and revision was 96.8% and 97.9%, respectively. CONCLUSIONS: Improved material properties combined with the possible use of larger diameter heads make AMC ceramics a promising alternative bearing option with seemingly comparable clinical outcomes reported by others with conventional ceramic bearings. Despite these encouraging results, however, meticulous technical precautions such as square seating and proper impaction in particular should be taken during liner insertion, because we did observe one liner dissociation and several patients with hip noises. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Mechanical Antiallodynic Effect of Intrathecal Nefopam in a Rat Neuropathic Pain Model.

Nefopam has a pharmacologic profile distinct from that of opioids or other anti-inflammatory drugs. Several recent studies demonstrate that nefopam has a mechanism of action similar to those of anti-depressants and anticonvulsants for treating neuropathic pain. The present study investigates the mechanical antiallodynic effect of nefopam using immunohistochemical study and western blot analysis in a rat neuropathic pain model. Twenty-eight male Sprague-Dawley rats were subjected to left fifth lumbar (L5) spinal nerve ligation and intrathecal catheter implantation, procedures which were not performed on the 7 male Sprague-Dawley rats in the sham surgery group (group S). Nefopam, either 10 or 100 µg/kg (group N10 or N100, respectively), and normal saline (group C) were intrathecally administered into the catheter every day for 14 days. The mechanical allodynic threshold of intrathecal nefopam was measured using a dynamic plantar aesthesiometer. Immunohistochemistry targeting cluster of differentiation molecule 11b (CD11b) and glial fibrillary acidic protein (GFAP) was performed on the harvested spinal cord at the level of L5. Extracellular signal-regulated kinase 1/2 (ERK 1/2) and cyclic adenosine monophosphate response element binding protein (CREB) were measured using western blot analysis. The N10 and N100 groups showed improved mechanical allodynic threshold, reduced CD11b and GFAP expression, and attenuated ERK 1/2 and CREB in the affected L5 spinal cord. In conclusion, intrathecal nefopam reduced mechanical allodynia in a rat neuropathic pain model. Its mechanical antiallodynic effect is associated with inhibition of glial activation and suppression of the transcription factors' mitogen-activated protein kinases in the spinal cord.

Modulation of lipid kinase PI4KIIα activity and lipid raft association of presenilin 1 underlies γ-secretase inhibition by ginsenoside (20S)-Rg3.

Amyloid ß-peptide (Aß) pathology is an invariant feature of Alzheimer disease, preceding any detectable clinical symptoms by more than a decade. To this end, we seek to identify agents that can reduce Aß levels in the brain via novel mechanisms. We found that (20S)-Rg3, a triterpene natural compound known as ginsenoside, reduced Aß levels in cultured primary neurons and in the brains of a mouse model of Alzheimer disease. The (20S)-Rg3 treatment induced a decrease in the association of presenilin 1 (PS1) fragments with lipid rafts where catalytic components of the γ-secretase complex are enriched. The Aß-lowering activity of (20S)-Rg3 directly correlated with increased activity of phosphatidylinositol 4-kinase IIα (PI4KIIα), a lipid kinase that mediates the rate-limiting step in phosphatidylinositol 4,5-bisphosphate synthesis. PI4KIIα overexpression recapitulated the effects of (20S)-Rg3, whereas reduced expression of PI4KIIα abolished the Aß-reducing activity of (20S)-Rg3 in neurons. Our results substantiate an important role for PI4KIIα and phosphoinositide modulation in γ-secretase activity and Aß biogenesis.

Modulation of mitochondrial function and autophagy mediates carnosine neuroprotection against ischemic brain damage.

BACKGROUND AND PURPOSE: Despite the rapidly increasing global burden of ischemic stroke, no therapeutic options for neuroprotection against stroke currently exist. Recent studies have shown that autophagy plays a key role in ischemic neuronal death, and treatments that target autophagy may represent a novel strategy in neuroprotection. We investigated whether autophagy is regulated by carnosine, an endogenous pleiotropic dipeptide that has robust neuroprotective activity against ischemic brain damage. METHODS: We examined the effect of carnosine on mitochondrial dysfunction and autophagic processes in rat focal ischemia and in neuronal cultures. RESULTS: Autophagic pathways such as reduction of phosphorylated mammalian target of rapamycin (mTOR)/p70S6K and the conversion of microtubule-associated protein 1 light chain 3 (LC3)-I to LC3-II were enhanced in the ischemic brain. However, treatment with carnosine significantly attenuated autophagic signaling in the ischemic brain, with improvement of brain mitochondrial function and mitophagy signaling. The protective effect of carnosine against autophagy was also confirmed in primary cortical neurons. CONCLUSIONS: Taken together, our data suggest that the neuroprotective effect of carnosine is at least partially mediated by mitochondrial protection and attenuation of deleterious autophagic processes. Our findings shed new light on the mechanistic pathways that this exciting neuroprotective agent influences.

Oxidative stress-mediated thrombospondin-2 upregulation impairs bone marrow-derived angiogenic cell function in diabetes mellitus.

OBJECTIVE: Circulating angiogenic cells play an essential role in angiogenesis but are dysfunctional in diabetes mellitus characterized by excessive oxidative stress. We hypothesize that oxidative stress-mediated upregulation of thrombospondin-2 (TSP-2), a potent antiangiogenic protein, contributes to diabetic bone marrow-derived angiogenic cell (BMAC) dysfunction. APPROACH AND RESULTS: BMACs were isolated from adult male type 2 diabetic db/db mice and control db/+ (C57BLKS/J) mice. In Matrigel tube formation assay, angiogenic function was impaired in diabetic BMACs, accompanied by increased oxidative stress and nicotinamide adenine dinucleotide phosphate oxidase activity. BMAC angiogenic function was restored by overexpression of dominant negative Rac1 or by overexpression of manganese superoxide dismutase. TSP-2 mRNA and protein were both significantly upregulated in diabetic BMACs, mediated by increased oxidative stress as shown by a decrease in TSP-2 level after overexpression of dominant negative Rac1 or manganese superoxide dismutase. Silencing TSP-2 by its small interfering RNA in diabetic BMACs improved BMAC function in tube formation, adhesion, and migration assays. Notably, the upregulation of TSP-2 was also found in BMACs from streptozotocin-induced type 1 diabetic mice, and normal BMACs with high glucose treatment. let-7f, a microRNA which has been related to endothelial angiogenic function, is found to play key role in TSP-2 increase, but let-7f did not directly interact with TSP-2 mRNA. CONCLUSIONS: The upregulation of TSP-2 mediated by increased oxidative stress contributes to angiogenesis dysfunction in diabetic BMACs.