One anastomosis gastric bypass ameliorates diabetic nephropathy via regulating the GLP-1-mediated Sirt1/AMPK/PGC1α pathway.

BACKGROUND: Diabetic nephropathy (DN), a complication of diabetes, is the most leading cause of end-stage renal disease. Bariatric surgery functions on the remission of diabetes and diabetes-related complications. One anastomosis gastric bypass (OAGB), one of popular bariatric surgery, can improve diabetes and its complications by regulating the glucagon-like peptide-1 (GLP-1) level. Meanwhile, GLP-1 can alleviate renal damage in high-fat-diet-induced obese rats. However, the effect of OAGB on renal injury remains uncertain in DN. METHODS: A diabetes model was elicited in rats via HFD feeding and STZ injection. The role and mechanism of OAGB were addressed in DN rats by the body and kidney weight and blood glucose supervision, oral glucose tolerance test (OGTT), enzyme-linked immunosorbent assay (ELISA), biochemistry detection, histopathological analysis, and western blot assays. RESULTS: OAGB surgery reversed the increase in body weight and glucose tolerance indicators in diabetes rats. Also, OAGB operation neutralized the DN-induced average kidney weight, kidney weight/body weight, and renal injury indexes accompanied with reduced glomerular hypertrophy, alleviated mesangial dilation and decreased tubular and periglomerular collagen deposition. In addition, OAGB introduction reduced the DN-induced renal triglyceride and renal cholesterol with the regulation of fatty acids-related proteins expression. Mechanically, OAGB administration rescued the DN-induced expression of Sirt1/AMPK/PGC1α pathway mediated by GLP-1. Pharmacological block of GLP-1 receptor inverted the effect of OAGB operation on body weight, glucose tolerance, renal tissue damage, and fibrosis and lipids accumulation in DN rats. CONCLUSION: OAGB improved renal damage and fibrosis and lipids accumulation in DN rats by GLP-1-mediated Sirt1/AMPK/PGC1α pathway.

The role of climate, vegetation, and soil factors on carbon fluxes in Chinese drylands.

Drylands dominate the trend and variability of the land carbon (C) sink. A better understanding of the implications of climate-induced changes in the drylands for C sink-source dynamics is urgently needed. The effect of climate on ecosystem C fluxes (gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem productivity (NEP)) in drylands has been extensively explored, but the roles of other concurrently changing factors, such as vegetation conditions and nutrient availability, remain unclear. We used eddy-covariance C-flux measurements from 45 ecosystems with concurrent information on climate (mean annual temperature (MAT) and mean annual precipitation (MAP)), soil (soil moisture (SM) and soil total nitrogen content (soil N)), and vegetation (leaf area index (LAI) and leaf nitrogen content (LNC)) factors to assess their roles in C fluxes. The results showed that the drylands in China were weak C sinks. GPP and ER were positively correlated with MAP, while they were negatively correlated with MAT. NEP first decreased and then increased with increasing MAT and MAP, and 6.6 °C and 207 mm were the boundaries for the NEP response to MAT and MAP, respectively. SM, soil N, LAI, and MAP were the main factors affecting GPP and ER. However, SM and LNC had the most important influence on NEP. Compared with climate and vegetation factors, soil factors (SM and soil N) had a greater impact on C fluxes in the drylands. Climate factors mainly affected C fluxes by regulating vegetation and soil factors. To accurately estimate the global C balance and predict the response of ecosystems to environmental change, it is necessary to fully consider the discrepant effects of climate, vegetation, and soil factors on C fluxes, as well as the cascade relationships between different factors.

Efficacy and Safety of One Anastomosis Gastric Bypass Versus Roux-en-Y Gastric Bypass for Obesity: a Meta-analysis and Systematic Review.

The objective of this review is to systematically review the efficacy and safety outcomes of one anastomosis gastric bypass (OAGB) with Roux-en-Y gastric bypass (RYGB). From inception to July 4, 2022, a systematic literature search was performed using PubMed, Embase, and Cochrane Library for randomized clinical trials comparing OAGB with RYGB in obesity. A meta-analysis performed using the RevMan 5.4.1 software evaluations was completed. We identified 1217 reports; after exclusions, eight trials with a total of 931 patients were eligible for analysis. Compared with RYGB, OAGB had multiple advantageous indexes. Examples include percent of excess weight loss (%EWL) at 12 months (P = 0.009), body mass index (BMI) at 2 years (P < 0.00001), early postoperative complication (P = 0.04), remission of dyslipidemia (P < 0.0001), and operative time (P < 0.00001). No significant statistical difference was observed in BMI at 6 months, %EWL at 6 months, BMI at 12 months, percent of excess body mass index loss (%EBMIL) at 2 years, BMI at 5 years, intraoperative complications, late postoperative complications, remission of type 2 diabetes mellitus, and dyslipidemia or gastroesophageal reflux disease remission between OAGB and RYGB. OAGB is no less effective than RYGB; no significant differences in weight loss efficacy were observed, and more large and long-term randomized controlled trials are needed to verify this. In addition, studies have shown that OAGB has a shorter operation time, fewer early postoperative complications, and a shorter learning curve, making it easier for young surgeons to perform.

Mapping Chinese annual gross primary productivity with eddy covariance measurements and machine learning.

Annual gross primary productivity (AGPP) is the basis for grain production and terrestrial carbon sequestration. Mapping regional AGPP from site measurements provides methodological support for analysing AGPP spatiotemporal variations thereby ensures regional food security and mitigates climate change. Based on 641 site-year eddy covariance measuring AGPP from China, we built an AGPP mapping scheme based on its formation and selected the optimal mapping way, which was conducted through analysing the predicting performances of divergent mapping tools, variable combinations, and mapping approaches in predicting observed AGPP variations. The reasonability of the selected optimal scheme was confirmed by assessing the consistency between its generating AGPP and previous products in spatiotemporal variations and total amount. Random forest regression tree explained 85 % of observed AGPP variations, outperforming other machine learning algorithms and classical statistical methods. Variable combinations containing climate, soil, and biological factors showed superior performance to other variable combinations. Mapping AGPP through predicting AGPP per leaf area (PAGPP) explained 86 % of AGPP variations, which was superior to other approaches. The optimal scheme was thus using a random forest regression tree, combining climate, soil, and biological variables, and predicting PAGPP. The optimal scheme generating AGPP of Chinese terrestrial ecosystems decreased from southeast to northwest, which was highly consistent with previous products. The interannual trend and interannual variation of our generating AGPP showed a decreasing trend from east to west and from southeast to northwest, respectively, which was consistent with data-oriented products. The mean total amount of generated AGPP was 7.03 ± 0.45 PgC yr-1 falling into the range of previous works. Considering the consistency between the generated AGPP and previous products, our optimal mapping way was suitable for mapping AGPP from site measurements. Our results provided a methodological support for mapping regional AGPP and other fluxes.

Ecosystem carbon use efficiency in ecologically vulnerable areas in China: Variation and influencing factors.

Ecologically vulnerable areas (EVAs) are regions with ecosystems that are fragile and vulnerable to degradation under external disturbances, e.g., environmental changes and human activities. A comprehensive understanding of the climate change characteristics of EVAs in China is of great guiding significance for ecological protection and economic development. The ecosystem carbon use efficiency (CUEe) can be defined as the ratio of the net ecosystem productivity (NEP) to gross primary productivity (GPP), one of the most important ecological indicators of ecosystems, representing the capacity for carbon transfer from the atmosphere to a potential ecosystem carbon sink. Understanding the variation in the CUEe and its controlling factors is paramount for regional carbon budget evaluation. Although many CUEe studies have been performed, the spatial variation characteristics and influencing factors of the CUEe are still unclear, especially in EVAs in China. In this study, we synthesized 55 field measurements (3 forestland sites, 37 grassland sites, 6 cropland sites, 9 wetland sites) of the CUEe to examine its variation and influencing factors in EVAs in China. The results showed that the CUEe in EVAs in China ranged from -0.39 to 0.67 with a mean value of 0.20. There were no significant differences in the CUEe among different vegetation types, but there were significant differences in CUEe among the different EVAs (agro-pastoral ecotones < Tibetan Plateau < arid and semiarid areas < Loess Plateau). The CUEe first decreased and then increased with increasing mean annual temperature (MAT), soil pH and soil organic carbon (SOC) and decreased with increasing mean annual precipitation (MAP). The most important factors affecting the CUEe were biotic factors (NEP, GPP, and leaf area index (LAI)). Biotic factors directly affected the CUEe, while climate (MAT and MAP) and soil factors (soil pH and SOC) exerted indirect effects. The results illustrated the comprehensive effect of environmental factors and ecosystem attributes on CUEe variation, which is of great value for the evaluation of regional ecosystem functions.

Photosynthetic capacity dominates the interannual variation of annual gross primary productivity in the Northern Hemisphere.

Annual gross primary productivity (AGPP) of terrestrial ecosystems is the largest carbon flux component in ecosystems; however, it's unclear whether photosynthetic capacity or phenology dominates interannual variation of AGPP, and a better understanding of this could contribute to estimation of carbon sinks and their interactions with climate change. In this study, observed GPP data of 494 site-years from 39 eddy covariance sites in Northern Hemisphere were used to investigate mechanisms of interannual variation of AGPP. This study first decomposed AGPP into three seasonal dynamic attribute parameters (growing season length (CUP), maximum daily GPP (GPPmax), and the ratio of mean daily GPP to GPPmax (αGPP)), and then decomposed AGPP into mean leaf area index (LAIm) and annual photosynthetic capacity per leaf area (AGPPlm). Furthermore, GPPmax was decomposed into leaf area index of DOYmax (the day when GPPmax appeared) (LAImax) and photosynthesis per leaf area of DOYmax (GPPlmax). Relative contributions of parameters to AGPP and GPPmax were then calculated. Finally, environmental variables of DOYmax were extracted to analyze factors influencing interannual variation of GPPlmax. Trends of AGPP in 39 ecosystems varied from -65.23 to 53.05 g C m-2 yr-2, with the mean value of 6.32 g C m-2 yr-2. Photosynthetic capacity (GPPmax and AGPPlm), not CUP or LAI, was the main factor dominating interannual variation of AGPP. GPPlmax determined the interannual variation of GPPmax, and temperature, water, and radiation conditions of DOYmax affected the interannual variation of GPPlmax. This study used the cascade relationship of "environmental variables-GPPlmax-GPPmax-AGPP" to explain the mechanism of interannual variation of AGPP, which can provide new ideas for the AGPP estimation based on seasonal dynamic of GPP.

Patterns and controls of vegetation productivity and precipitation-use efficiency across Eurasian grasslands.

Elucidating aboveground net primary production (ANPP) and precipitation-use efficiency (PUE) spatial variations and mechanisms are essential for predicting how ecosystem functioning will respond to future climate change. However, a comprehensive recognition of spatial patterns of ANPP and PUE across continental scale is still lacking. Here, we integrated long-term GIMMS NDVI remote sensing, field survey ANPP and meteorological datasets to reveal the spatial variations and controls of ANPP and PUE across Eurasian grasslands for the first time. The results showed that the mean value of ANPP and PUE of Eurasian grasslands were 40.20 ± 0.40 g C m-2 yr-1 and 0.15 ± 0.01 g C m-2 mm-1, respectively. At the continental scale, the ANPP and PUE showed unimodal patterns along mean annual precipitation (MAP) and hydrothermal index (HT) gradients, while a piecewise linear pattern along mean annual temperature (MAT) gradients. The MAP exerted positive effect on the ANPP in desert and temperate grasslands, while negative effect on the ANPP in alpine grasslands. Conversely, the MAT negatively affected the ANPP in desert and temperate grasslands, while positively affected the ANPP in alpine grasslands. The results indicated that the hydrothermal conditions coupled with the transition of vegetation types and its different responses combinedly shaped the spatial patterns of ANPP and PUE in Eurasian grasslands. This study advanced our knowledge of the spatial variations of ANPP and PUE at continental scale, providing theoretical information for predicting productivity and water use changes of arid and semi-arid grasslands under climate change in the future.

Differences in biological activities between recombinant human paraoxonase 1 (rhPON1) subtype isozemys R/Q as antidotes against organophosphorus poisonings.

Paraoxonase 1 (PON1) is a type of aromatic esterase widely existing in mammals. It can hydrolyze various kinds of compounds effectively in vivo and in vitro. Previous studies have confirmed that PON1 can be used as antidote against organophosphorus poisonings (OPs). In this study, we obtained two subtype isozymes (i.e. rhPON1R192 and rhPON1Q192) by gene recombination and compared their detoxification effects against different OPs in rats. The rhPON1R192 demonstrated better detoxification effect against chlorpyrifos poisoning than the rhPON1Q192, whose detoxification effect against diazinon poisoning was prior to the former. Both of them showed poor detoxification effect against trithion. Therefore, we concluded that, to different OPs, better detoxification effect may be achieved by selecting the PON1 subtype isozyme with higher specific hydrolytic activity.

Mechanisms of relaxant action of 3-O-methylquercetin in isolated guinea pig trachea.

We investigated the mechanisms of action of 3-O-methylquercetin (3-MQ), isolated from Rhamnus nakaharai (Hayata) Hayata (Rhamnaceae) which is used as a folk medicine for treating constipation, inflammation, tumors and asthma in Taiwan. The tension changes of tracheal segments were isometrically recorded on a polygraph. 3-MQ concentration-dependently relaxed histamine (30 microM)-, carbachol (0.2 microM)- and KCl (30 mM)-induced precontractions, and inhibited cumulative histamine-, and carbachol-induced contractions in a non-competitive manner. 3-MQ also concentration-dependently and non-competitively inhibited cumulative Ca(2+)-induced contractions in depolarized (K(+), 60 mM) guinea-pig trachealis. The nifedipine (10 microM)-remaining tension of histamine (30 microM)-induced precontraction was further relaxed by 3-MQ, suggesting that no matter whether VDCCs were blocked or not, 3-MQ may have other mechanisms of relaxant action. The relaxant effect of 3-MQ was unaffected by the removal of epithelium or by the presence of propranolol (1 microM), 2',5'-dideoxyadenosine (10 microM), methylene blue (25 microM), glibenclamide (10 microM), N(omega)-nitro-L-arginine (20 microM), or alpha-chymotrypsin (1 U/ml). However, 3-MQ (7.5 - 15 microM) and IBMX (3 - 6 microM), a positive control, produced parallel and leftward shifts of the concentration-response curve of forskoline (0.01 - 3 microM) or nitroprusside (0.01 - 30 microM). 3-MQ or IBMX at various concentrations (10 - 300 microM) concentration-dependently and significantly inhibited cAMP- and cGMP-PDE activities of the trachealis. The IC50 values of 3-MQ were estimated to be 13.8 and 14.3 microM, respectively. The inhibitory effects of 3-MQ on both enzyme activities were not significantly different from those of IBMX, a non-selective PDE inhibitor. The above results reveal that the mechanisms of relaxant action of 3-MQ may be due to its inhibitory effects on both PDE activities and its subsequent reducing effect on [Ca(2+)]i of the trachealis.3-MQ:3-O-methylquercetinIBMX:3-isobutyl-1-methylxanthineVDCCs:voltage dependent calcium channelscAMP:adenosine 3',5'-cyclic monophosphatecGMP:guanosine 3',5'-cyclic monophosphatePDE:phosphodiesteraseWe investigated the mechanisms of action of 3-O-methylquercetin (3-MQ), isolated from Rhamnus nakaharai (Hayata) Hayata (Rhamnaceae) which is used as a folk medicine for treating constipation, inflammation, tumors and asthma in Taiwan. The tension changes of tracheal segments were isometrically recorded on a polygraph. 3-MQ concentration-dependently relaxed histamine (30 microM)-, carbachol (0.2 microM)- and KCl (30 mM)-induced precontractions, and inhibited cumulative histamine-, and carbachol-induced contractions in a non-competitive manner. 3-MQ also concentration-dependently and non-competitively inhibited cumulative Ca(2+)-induced contractions in depolarized (K(+), 60 mM) guinea-pig trachealis. The nifedipine (10 microM)-remaining tension of histamine (30 microM)-induced precontraction was further relaxed by 3-MQ, suggesting that no matter whether VDCCs were blocked or not, 3-MQ may have other mechanisms of relaxant action. The relaxant effect of 3-MQ was unaffected by the removal of epithelium or by the presence of propranolol (1 microM), 2',5'-dideoxyadenosine (10 microM), methylene blue (25 microM), glibenclamide (10 microM), N(omega)-nitro-L-arginine (20 microM), or alpha-chymotrypsin (1 U/ml). However, 3-MQ (7.5 - 15 microM) and IBMX (3 - 6 microM), a positive control, produced parallel and leftward shifts of the concentration-response curve of forskoline (0.01 - 3 microM) or nitroprusside (0.01 - 30 microM). 3-MQ or IBMX at various concentrations (10 - 300 microM) concentration-dependently and significantly inhibited cAMP- and cGMP-PDE activities of the trachealis. The IC50 values of 3-MQ were estimated to be 13.8 and 14.3 microM, respectively. The inhibitory effects of 3-MQ on both enzyme activities were not significantly different from those of IBMX, a non-selective PDE inhibitor. The above results reveal that the mechanisms of relaxant action of 3-MQ may be due to its inhibitory effects on both PDE activities and its subsequent reducing effect on [Ca(2+)]i of the trachealis.3-MQ:3-O-methylquercetinIBMX:3-isobutyl-1-methylxanthineVDCCs:voltage dependent calcium channelscAMP:adenosine 3',5'-cyclic monophosphatecGMP:guanosine 3',5'-cyclic monophosphatePDE:phosphodiesterase