Fibrinogen, fibrin degradation products and risk of sarcopenia.

BACKGROUND & AIMS: Increasing data suggests that chronic low-grade inflammation plays an important role on development of sarcopenia. The present study was designed to identify the association between fibrinogen, fibrin degradation products (FDP) and sarcopenia risk in hospitalized old patients. METHODS: A total of 437 patients were enrolled in this cross-sectional study (148 with sarcopenia and 289 without sarcopenia). Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia (AWGS) 2019 criteria. Body composition, grip strength and gait speed were performed to participants. Fibrinogen, FDP levels were measured. Logistic regression analyses were carried out to assess the association between fibrinogen and sarcopenia, between FDP and sarcopenia, respectively. RESULTS: Compared to non-sarcopenic patients, fibrinogen and FDP levels were found to be higher in the sarcopenic group (3.07 g/L vs 2.79 g/L, 1.75 µg/mL vs 1.00 µg/mL, respectively, p < 0.05). Multiple linear regression analysis showed a significant negative association between fibrinogen and gait speed (ß: -0.164, p = 0.008), and muscle strength (ß: -0.231, p < 0.001). Multivariable logistic regression analysis showed that fibrinogen and FDP were independently associated with sarcopenia (odds ratio 1.32 [95% confidence interval 1.03, 1.70], p = 0.009; odds ratio 1.07 [95% confidence interval 1.01, 1.19], p = 0.049, respectively). ROC curve revealed that the cutoff values of fibrinogen and FDP to predict sarcopenia risk were 2.54 g/L and 1.15 µg/mL, respectively. CONCLUSIONS: In hospitalized old patients, serum fibrinogen and FDP levels are elevated in sarcopenia patients than those without sarcopenia. Fibrinogen and FDP are associated with sarcopenia in a concentration-dependent manner.

Parent B2 N2 -Perylenes with Different BN Orientations.

Introducing BN units into polycyclic aromatic hydrocarbons expands the chemical space of conjugated materials with novel properties. However, it is challenging to achieve accurate synthesis of BN-PAHs with specific BN positions and orientations. Here, three new parent B2 N2 -perylenes with different BN orientations are synthesized with BN-naphthalene as the building block, providing systematic insight into the effects of BN incorporation with different orientations on the structure, (anti)aromaticity, crystal packing and photophysical properties. The intermolecular dipole-dipole interaction shortens the π-π stacking distance. The crystal structure, (anti)aromaticity, and photophysical properties vary with the change of BN orientation. The revealed BN doping effects may provide a guideline for the synthesis of BN-PAHs with specific stacking structures, and the synthetic strategy employed here can be extended toward the synthesis of larger BN-embedded PAHs with adjustable BN patterns.

Inhibition of TLR9 attenuates skeletal muscle fibrosis in aged sarcopenic mice via the p53/SIRT1 pathway.

Sarcopenia is an age-related syndrome characterized by a gradual loss of muscle mass and function, but its pathophysiological mechanism remains unclear. Skeletal muscle extracellular matrix (ECM) remodeling is an important pathological change in sarcopenia, and fibrosis is the most obvious manifestation of this change. We found that the expression of the immunoreceptor Toll-like receptor 9 (TLR9) is significantly increased in skeletal muscle in aged mice and is positively related to muscle fibrosis. Moreover, in previous reports, the longevity gene Sirt1 was reported to attenuate ECM deposition and improve muscle function. In this study, we hypothesized that TLR9 modulated skeletal muscle fibrosis via Sirt1. We used TLR9 knockout (TLR9 KO) mice and C57 mice, and grip strength and body composition were compared at different ages. We found that TLR9 knockout significantly attenuated skeletal muscle fibrosis and improved muscle function in aged mice. Furthermore, silent information regulator 1 (Sirt1) activity in mice was inhibited by Ex527, which is a specific inhibitor of Sirt1. Negative Sirt1 regulation via the activation of TLR9-related signaling pathways participated in skeletal muscle fibrosis in the sarcopenic mice, and this process might mediated by the Sirt1/Smad signaling pathway. Our findings revealed that fibrosis changes in the gastrocnemius muscle in sarcopenic mice are closely related to TLR9 activation, and TLR9 modulation could be a therapeutic strategy for combating sarcopenia during aging.

Metformin attenuates diabetes-induced tau hyperphosphorylation in vitro and in vivo by enhancing autophagic clearance.

Diabetes mellitus (DM) can increase the risk of Alzheimer's disease (AD) in patients. However, no effective approaches are available to prevent its progression and development. Recently, autophagy dysfunction was identified to be involved in the pathogenesis of neurodegenerative diseases. This study was designed to investigate the effect of metformin on hyperphosphorylated tau proteins in diabetic encephalopathy (DE) by regulating autophagy clearance. db/db mice were randomly divided into four groups, db/+ mice were used as control group. Twelve-week old male db/db mice received consecutive intraperitoneal injection of 200 mg/kg/d metformin or (and) 10 mg/kg/d chloroquine for eight weeks. Morris water maze (MWM) tests were performed to test cognitive functions before the mice were euthanized. Metformin attenuated cognitive impairment in db/db mice, reduced hyperphosphorylated tau proteins, restored the impaired autophagy in diabetic mice, all of which were reversed by inhibiting of autophagy activity. In high glucose-cultured HT22 cells, metformin increased autophagy in a dose-dependent manner. Besides, metformin enhanced autophagy activity in an AMPK dependent manner. These data show that metformin may reduce tauopathy and improve cognitive impairment in db/db mice by modulating autophagy through the AMPK dependent pathway. These findings highlight metformin as a new therapeutic strategy for the treatment of DE.

[Effect of resveratrol on forelimb grip strength and myofibril structure in aged rats].

OBJECTIVE: To observe the effect of resveratrol on muscle mass, forelimb grip strength, myofibril structure and AMPK/sirt1 pathway in skeletal muscles of aged rats. METHODS: Twenty aged (25 months old) SD rats were randomly divided into aged control group and resveratrol treatment group (10 in each group) with 10 young (6 months old) rats served as the young control group. In resveratrol treatment group, the rats were treated with resveratrol (mixed in chow) for 6 weeks. After the treatment, the mass of the gastrocnemius was measured and the sarcopenia index (SI) was calculated as the gastrocnemius mass (mg) to body weight (g) ratio. The forelimb grip strength of the rats was measured using a electronic grip strength meter, and the lengths of the sarcomere, I-band, A-band and H-zone of the myofibrils were determined by transmission electron microscopy. RESULTS: Compared with the young rats, the aged control rats had significantly lower SI of the gastrocnemius (P<0.05) and grip strength (P<0.05) with increased lengths of the sarcomere, A-band, I-band and H-zone (P<0.05) and lowered expressions of AMPK, P-AMPK, and sirt1 protein (P<0.05). Resveratrol treatment of the aged rats significantly increased the forelimb grip strength, reduced the lengths of sarcomere length, I-band and H-zone (P<0.05) and increased, P-AMPK, sirt1 protein expressions (P<0.05) without significantly affecting the SI (P>0.05) or the A-band length (P>0.05). CONCLUSION: Resveratrol does not improve the muscle mass but can increase the forelimb grip strength in aged rats possibly by activating AMPK/sirt1 pathway to improve the ultrastructure of the myofibrils.

The effect of exercise, resveratrol or their combination on Sarcopenia in aged rats via regulation of AMPK/Sirt1 pathway.

Sarcopenia is an age-related syndrome characterized by progressive loss of muscle mass and function. Exercise is an important strategy to prolong life and increase muscle mass, and resveratrol has been shown a variety beneficial effects on skeletal muscle. In the present study, we investigated the potential efficacy of using short-term exercise (six weeks), resveratrol (150mg/kg/day), or combined exercise+resveratrol (150mg/kg/day) on gastrocnemius muscle mass, grip strength, cross-sectional area and microscopic morphology in aged rats, and explored the potential mechanism at the apoptosis level. Six months old SD rats were used as young control group and 24months old SD rats were adopted as aged group. After six weeks intervention, the data provide evidence that exercise, resveratrol or their combination significantly increase the relative grip strength and muscle mass in aged rats (P<0.05). Electron microscopy discovered a significant increase in sarcomere length, I-band and H-zone in aged rats (P<0.05), and exercise, resveratrol or their combination significantly reduced the increasement (P<0.05). Moreover, light microscopy revealed a significant increase on Feret's diameter and cross-sectional area (CSA) in aged rats (P<0.05), but exercise and resveratrol did not show significant effects on them (P>0.05). Furthermore, exercise, resveratrol or their combination significantly increased the expression of p-AMPK and SIRT1, decreased the expression of acetyl P53 and Bax/Bcl-2 ratio in aged rats (P<0.05). These findings show that aged rats show significant changes in gastrocnemius muscle morphology and ultrastructure, and the protective effects of exercise, resveratrol and their combination are probably associated with anti-apoptotic signaling pathways through activation of AMPK/Sirt1.

Angiotensin-(1-7) administration attenuates Alzheimer's disease-like neuropathology in rats with streptozotocin-induced diabetes via Mas receptor activation.

Diabetes mellitus (DM) is associated with cognitive deficits and an increased risk of Alzheimer's disease (AD). Recently, a newly identified heptapeptide of the renin-angiotensin system (RAS), angiotensin-(1-7) [Ang-(1-7)], was found to protect against brain damage. This study investigated the effects of Ang-(1-7) on diabetes-induced cognitive deficits. Sprague-Dawley rats were randomly divided into four groups. Diabetes was induced via single i.p. streptozotocin (STZ) injections. Ten weeks after diabetes induction, rats in each group received an intracerebral-ventricular (ICV) infusion of either vehicle, Ang-(1-7) alone, or Ang-(1-7)+A779 daily for two weeks. At the end of the study, Morris water maze (MWM) tests were performed to test cognitive functions before the rats were euthanized. Ang-(1-7) treatment significantly reduced escape latencies in diabetic rats in acquisition trials and markedly enhanced platform area crossing frequency and time spent in the target quadrant in probe trials (3.0±0.39 vs. 1.0±0.33, 39.39±1.11% vs. 25.62±3.07%, respectively, P<0.01). Ang-(1-7) treatment ameliorated damage to the ultrastructure of hippocampal synapses, reduced the expression of hippocampal phospho-tau at Ser396 (P<0.01), Ser404 (P<0.01) and Ser202/Thr205 (P<0.05), and decreased amyloid-ß oligomer and both soluble and insoluble ß-amyloid peptide 1-42 (Aß 1-42) and Aß 1-40 levels (P<0.01). These protective effects were significantly reversed by the co-administration of A779. These findings show that Ang-(1-7) is a promising therapeutic target for diabetes-induced cognitive impairment. The neuroprotective effects of Ang-(1-7) were mainly through Mas receptor (MasR) activation.

[Effects of ghrelin on hippocampal DKK-1 expression and cognitive function in rats with diabetes mellitus].

OBJECTIVE: To explore the effects of ghrelin on learning and memory abilities and expressions of DKK-1 and ß-catenin in the hippocampus of diabetic rats. METHODS: Sixty male SD rats were randomly assigned into 4 groups, namely the control group, diabetic group, ghrelin-treated diabetic group (DM1 group), and ghrelin- and D-lys3-GHRP-6 (a GHSR-1a receptor antagonist)-treated diabetic group (DM2 group). Diabetic rat models were established by a single intraperitoneal injection of streptozotocin (65 mg/kg). The learning and memory abilities of the rats were assessed with Morris water maze (MWM) test. The ultrastructure of the hippocampal CA1 area of the rats were observed with electron microscopy. Serum levels of DKK-1 were examined by ELISA, and the expressions of DKK-1 and ß-catenin in the hippocampus were examined by quantitative real-time PCR and Western blotting. RESULTS: Compared with the control group, the diabetic rats exhibited significantly impaired learning and memory abilities (P<0.05), increased expression of DKK-1 and lowered ß-catenin expression in the hippocampus (P<0.05), significant ultrastructural injuries and disordered arrangement of neurons with the nuclear pycnosis in the hippocampal CA1 area. Ghrelin treatment of the diabetic rats obviously improved their learning and memory abilities (P<0.05), reduced DKK-1 and increased ß-catenin expressions (P<0.05), ameliorated ultrastructural damages in the hippocampal CA1 area and restored normal neuronal alignment with clear cell layers. Such effects of ghrelin were antagonized by treatment with D-lys3-GHRP-6 in the diabetic rats. CONCLUSION: Ghrelin can alleviate learning and memory dysfunction in diabetic rats possibly by down-regulating the expressions of DKK-1 and activating the WNT signaling pathways.

Age and risk for depression among the elderly: a meta-analysis of the published literature.

OBJECTIVE: The goal of this study was to determine the relationship between age and risk for depression among the old and the oldest old. Method MEDLINE, EMBASE, and the Cochrane Library database were used to identify potential studies. The studies were divided into cross-sectional and longitudinal subsets. For each study, the numbers of the total participants, cases (for cross-sectional study), or incident cases (for longitudinal study) of depression in each age group were extracted and entered into Review Manager 4.2 software. Qualitative meta-analyses of cross-sectional studies and of longitudinal studies were performed. For prevalence and incidence rates of depression, odds risk (OR) and relative risk (RR) were calculated, respectively. RESULTS: The qualitative meta-analyses showed that, compared with younger participants (above vs. below 65 years, above vs. below 70 years, above vs. below 75 years, and above vs. below 80 years), older age groups had a significantly higher risk for depression. (All of the ORs and RRs were significant.) Compared with participants aged 55-89, those aged above 90 years had no higher risk for depression. (Neither the OR nor the RR was significant.) CONCLUSIONS: Despite the methodological limitations of this meta-analysis, older age appears to be an important risk factor for depression in the general elderly population (aged below 80 years), but not in the oldest population (aged above 85 years).

Ghrelin-attenuated cognitive dysfunction in streptozotocin-induced diabetic rats.

Diabetic encephalopathy is clinically characterized by acquired behavior and cognitive dysfunction but its pathogenesis is not clear. This study aimed to explore the pathogenesis of diabetic encephalopathy and the mechanisms of ghrelin to ameliorate cognitive dysfunction in diabetic rats. Thirty-six streptozotocin diabetic rat models were established; 12 weeks later, all the rats were randomly divided into 3 groups [diabetic model group (D), ghrelin treatment group (T1), and ghrelin and D-lys-3-GHRP-6 treatment group (T2)] of 12 each. Twelve normoglycemic rats were classified in the normal group (N). Learning and memory behaviors were measured using a spatial version of the Morris water maze test. The brain-derived neurotrophic factor (BDNF), cAMP responsive element binding protein (CREB), phosphorylated CREB (p-CREB), phosphorylated ERK1/2 (p-ERK1/2), caspase-3, and Bcl-xl protein expressions in the hippocampi of all the rats were detected using immunohistochemistry. The mRNA expressions of BDNF, CREB, and caspase-3 were examined using reverse transcription-polymerase chain reaction. The hippocampus neuronal apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling method. We found that learning and memory level in the ghrelin treatment group improved significantly, expression of Bcl-xl, BDNF, CREB, p-CREB, and p-ERK1/2 in the hippocampus was increased in the ghrelin treatment group, and the number of apoptotic neurons in the hippocampus decreased remarkably. Our results showed that the changes of BDNF, CREB, and hippocampus neuronal apoptosis might be involved in the pathogenesis of diabetic encephalopathy. We suggested that ghrelin improved cognitive ability in streptozotocin-induced diabetic rats by improving the expressions of BDNF and CREB and by attenuating hippocampus neuronal apoptosis. The effects of ghrelin depend on the receptor of ghrelin, GHSR-1a, and ERK1/2 pathway.

[Study on the change of myocardial cell and matrix in the rats with insulin resistance and type 2 diabetes mellitus].

OBJECTIVE: To explore the injury of insulin resistance on cardiac muscle cell and matrix, and the relationship between insulin resistance and diabetic cardiomyopathy. METHODS: Twenty four Wistar rats of 6 months were randomly divided into normal control (N), insulin resistance group (I), diabetic group (D). Euglycemic insulin clamp technique (EICT) was used to determine insulin resistance (IR). Cadiocyte apoptosis was evaluated by TUNEL. Heart weight (HW) and body weight (BW) were measured to calculate HW/BW. Ultra-microstructure of cardiac muscle cell and structure of heart was observed. Masson dyeing, hydroxyproline detection and immunohistochemistry were used to measure the levels of collagen protein. RESULTS: Compared with controls, GIR decreased remarkably in D group and I group (P < 0.01). The number of apoptosis cell in I group was lower than that of D group (P < 0.01), and higher than that of N group (P < 0.01). Injury change of ultramicrostructure of myocardial cell was observed in the rats with type 2 diabetes mellitus or insulin resistance. Interstitial fibrosis of heart occurred in D group and I group. Content of Hydroxyproline, the level of I , III type of collagen, and the total level of collagen in I group were lower than those in D group, and higher than those in N group (P < 0.05). CONCLUSION: Insulin resistance in the rats with type 2 diabetes mellitus or insulin resistance can injury myocardial cell and matrix.