Insights into Stereoselectivity Switch in Michael Addition-Initiated Tandem Mannich Cyclizations and Their Extension from Enamines to Vinyl Ethers.

Both cis- and trans- tetracyclic spiroindolines are the core of many important biologically active indole alkaloids, but the divergent synthesis of these important motifs is largely hampered by the limited stereoselectivity control. A facile stereoinversion protocol is reported here in Michael addition-initiated tandem Mannich cyclizations for constructing tetracyclic spiroindolines, providing an easy access to two diastereoisomeric cores of monoterpene indole alkaloids with high selectivity. The mechanistic studies including in situ NMR experiments, control experiments, and DFT calculations reveal that the reaction undergoes a unique retro-Mannich/re-Mannich rearrangement including a C-C bond cleavage that is very rare for a saturated six-membered carbocycle. Insights into the stereoinversion process have been uncovered, and the major effects were determined to be the electronic properties of N-protecting groups of the indole with the aid of Lewis acid catalysts. By understanding these insights, the stereoselectivity switching strategy is also smoothly applied from enamine substrates to vinyl ether substrates, which are enriched greatly for the divergent synthesis and stereocontrol of monoterpene indole alkaloids. The current reaction also proves to be very practical and was successfully applied to the gram-scale total synthesis of strychnine and deethylibophyllidine in short routes.

Triglyceride-glucose index and non-culprit coronary plaque characteristics assessed by optical coherence tomography in patients following acute coronary syndrome: A cross-sectional study.

Background: Triglyceride-glucose (TyG) index, a novel surrogate marker of insulin resistance, has been demonstrated to be significantly associated with cardiovascular disease. It remains indistinct regarding the association between TyG index and non-culprit coronary plaque characteristics in patients following acute coronary syndrome (ACS). Methods: The present study retrospectively recruited patients who were diagnosed with ACS and underwent non-culprit optical coherence tomography (OCT) examination. The study population was divided into 2 groups based on the median of TyG index, which was calculated as Ln [fasting triglyceride (TG) (mg/dL) × fasting blood glucose (FBG) (mg/dL)/2]. The non-culprit plaque characteristics were determined by interpreting OCT images in accordance with the standard of previous consensus. Results: 110 patients (54.8 ± 12.1 years, 24.5% female) with 284 non-culprit plaques were included in the current analysis. TyG index was closely associated with high-risk plaque characteristics. Elevated TyG index was consistent to be an independent indicator for thin-cap fibroatheroma (TCFA) [odds ratio (OR) for per 1-unit increase 4.940, 95% confidence interval (CI) 1.652-14.767, P = 0.004; OR for taking lower median as reference 2.747, 95% CI 1.234-7.994, P = 0.011] and ruptured plaque (OR for per 1-unit increase 7.065, 95% CI 1.910-26.133, P = 0.003; OR for taking lower median as reference 4.407, 95% CI 1.208-16.047, P = 0.025) in fully adjusted model. The predictive value of TyG index for TCFA and ruptured plaque was moderate-to-high, with the area under the receiver operating characteristic curve (AUC) of 0.754 and 0.699 respectively. The addition of TyG index into a baseline model exhibited an incremental effect on the predictive value for TCFA, manifested as an increased AUC (0.681, 95% CI 0.570-0.793 vs. 0.782, 95% CI 0.688-0.877, P = 0.042), and significant continuous net reclassification improvement (0.346, 95% CI 0.235-0.458, P < 0.001) and integrated discrimination improvement (0.221, 95% CI 0.017-0.425, P = 0.034). TyG index failed to play an incremental effect on predicting ruptured plaque. Conclusion: TyG index, which is simply calculated from fasting TG and FBG, can be served as an important and independent risk predictor for high-risk non-culprit coronary plaques in patients following ACS.

Visceral Adiposity Index Plays an Important Role in Prognostic Prediction in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome and Type 2 Diabetes Mellitus Undergoing Percutaneous Coronary Intervention.

Background: Visceral adiposity index (VAI), a surrogate marker of adiposity and insulin resistance, has been demonstrated to be significantly related to cardiovascular disease. It remains indistinct whether VAI predicts adverse prognosis after percutaneous coronary intervention (PCI) for patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and type 2 diabetes mellitus (T2DM). Methods: A total of 798 participants who met the enrollment criteria were finally brought into this study. VAI was determined by waist circumference, body mass index, fasting triglyceride, and high-density lipoprotein cholesterol as previously reported. Adverse prognosis included all-cause death, non-fatal myocardial infarction, non-fatal ischemic stroke, and ischemia-driven revascularization, the composite of which was defined as the primary endpoint. Results: Higher VAI maintained as a significant and independent risk predictor for the primary endpoint, regardless of the adjustment for the various multivariate models [hazard ratio (95% CI) for fully adjusted model: 2.72 (2.02-3.68), p < 0.001]. The predictive value of VAI was further confirmed in sensitivity analysis where VAI was taken as a continuous variate. There was a dose-response relationship of VAI with the risk of the primary endpoint (p for overall association < 0.001). Moreover, the ability of VAI on the prediction of the primary endpoint was consistent between subgroups stratified by potential confounding factors (all p for interaction > 0.05). VAI exhibited a significant incremental effect on risk stratification for the primary endpoint beyond existing risk scores, expressed as increased Harrell's C-index, significant continuous net reclassification improvement, and significant integrated discrimination improvement. Conclusion: VAI is a significant indicator for predicting worse prognosis and plays an important role in risk stratification among patients with NSTE-ACS and T2DM undergoing elective PCI. The present findings require further large-scale, prospective studies to confirm.

Comparison of various insulin resistance surrogates on prognostic prediction and stratification following percutaneous coronary intervention in patients with and without type 2 diabetes mellitus.

BACKGROUND: Insulin resistance (IR), evaluation of which is difficult and complex, is closely associated with cardiovascular disease. Recently, various IR surrogates have been proposed and proved to be highly correlated with IR assessed by the gold standard. It remains indistinct whether different IR surrogates perform equivalently on prognostic prediction and stratification following percutaneous coronary intervention (PCI) in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients with and without type 2 diabetes mellitus (T2DM). METHODS: The present study recruited patients who were diagnosed with NSTE-ACS and successfully underwent PCI. IR surrogates evaluated in the current study included triglyceride-glucose (TyG) index, visceral adiposity index, Chinese visceral adiposity index, lipid accumulation product, and triglyceride-to-high density lipoprotein cholesterol ratio, calculations of which were conformed to previous studies. The observational endpoint was defined as the major adverse cardiovascular and cerebrovascular events (MACCE), including cardiac death, non-fatal myocardial infarction, and non-fatal ischemic stroke. RESULTS: 2107 patients (60.02 ± 9.03 years, 28.0% female) were ultimately enrolled in the present study. A total of 187 (8.9%) MACCEs were documented during the 24-month follow-up. Despite regarding the lower median as reference [hazard ratio (HR) 3.805, 95% confidence interval (CI) 2.581-5.608, P < 0.001] or evaluating 1 normalized unit increase (HR 1.847, 95% CI 1.564-2.181, P < 0.001), the TyG index remained the strongest risk predictor for MACCE, independent of confounding factors. The TyG index showed the most powerful diagnostic value for MACCE with the highest area under the receiver operating characteristic curve of 0.715. The addition of the TyG index, compared with other IR surrogates, exhibited the maximum enhancement on risk stratification for MACCE on the basis of a baseline model (Harrell's C-index: 0.708 for baseline model vs. 0.758 for baseline model + TyG index, P < 0.001; continuous net reclassification improvement: 0.255, P < 0.001; integrated discrimination improvement: 0.033, P < 0.001). The results were consistent in subgroup analysis where similar analyses were performed in patients with and without T2DM, respectively. CONCLUSION: The TyG index, which is most strongly associated with the risk of MACCE, can be served as the most valuable IR surrogate for risk prediction and stratification in NSTE-ACS patients receiving PCI, with and without T2DM.

Prognostic Significance of Relative Hyperglycemia after Percutaneous Coronary Intervention in Patients with and without Recognized Diabetes.

BACKGROUND: The research on the association between the relative glycemic level postpercutaneous coronary intervention (PCI) and adverse prognosis in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients is relatively inadequate. OBJECTIVE: The study aimed to identify whether the glycemic level post-PCI predicts adverse prognosis in NSTE-ACS patients. METHODS: Patients (n=2465) admitted with NSTE-ACS who underwent PCI were enrolled. The relative glycemic level post-procedure was calculated as blood glucose level post-PCI divided by HbA1c level, which was named post-procedural glycemic index (PGI). The primary observational outcome of this study was major adverse cardiovascular events (MACE) [defined as a composite of all-cause death, non-fatal myocardial infarction (MI) and any revascularization]. RESULTS: The association between PGI and MACE rate is presented as a U-shape curve. Higher PGIs [hazard ratio (HR): 1.669 (95% confidence interval (CI): 1.244-2.238) for the third quartile (Q3) and 2.076 (1.566-2.753) for the fourth quartile (Q4), p<0.001], adjusted for confounding factors, were considered to be one of the independent predictors of MACE. The association between the PGI and the risk of MACE was more prominent in the non-diabetic population [HR (95%CI) of 2.356 (1.456-3.812) for Q3 and 3.628 (2.265-5.812) for Q4, p<0.001]. There were no significant differences in MACE risk between PGI groups in the diabetic population. CONCLUSION: Higher PGI was a significant and independent predictor of MACE in NSTE-ACS patients treated with PCI. The prognostic effect of the PGI is more remarkable in subsets without pre-existing diabetes than in the overall population. The predictive value of PGI was not identified in the subgroup with diabetes.

Triglyceride-Glucose Index as a Surrogate Marker of Insulin Resistance for Predicting Cardiovascular Outcomes in Nondiabetic Patients with Non-ST-Segment Elevation Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention.

AIM: The triglyceride-glucose index (TyG index) is proposed as a surrogate parameter for insulin resistance (IR) and, when elevated, is related to increased cardiovascular risks. Whether the TyG index is of great value in predicting adverse prognosis for individuals diagnosed with non-ST-segment elevation acute coronary syndrome (NSTE-ACS), who received elective percutaneous coronary intervention (PCI), and without recognized diabetes remains unclear. METHODS: Overall, 1,510 subjects diagnosed with NSTE-ACS, who received elective PCI, and without recognized diabetes were enrolled in the current study. All participants received a routine follow-up after discharge. The TyG index was obtained from the following equation: napierian logarithmic (ln) [fasting triglyceride (TG, mg/dL)×fasting blood glucose (FBG, mg/dL)/2]. Adverse cardiovascular events included all-cause death, nonfatal myocardial infarction (MI), nonfatal ischemic stroke, and ischemia-driven revascularization, composite of which was defined as the primary endpoint. RESULTS: Overall, 316 (20.9%) endpoint events were documented during a 48-month follow-up. Despite adjusting for confounding variates, the TyG index remains to be a significant risk predictor for the primary endpoint, with a hazard ratio (HR) [95% confidence interval (CI)] of 2.433 (1.853-3.196) (P＜0.001). A significant enhancement on the predictive performance for the primary endpoint emerged when adding the TyG index into a baseline model [area under the receiver-operating characteristic (ROC) curve (AUC), 0.835 for baseline model vs. 0.853 for baseline model＋TyG index, P＜0.001; net reclassification improvement (NRI), 0.194, P＜0.001; integrated discrimination improvement (IDI), 0.023, P=0.007]. CONCLUSIONS: The TyG index is an independent risk predictor for adverse cardiovascular events in nondiabetic subjects diagnosed with NSTE-ACS and who received elective PCI. Further prospective studies are needed to verify these findings.

Prognostic impact of estimated remnant-like particle cholesterol in patients with differing glycometabolic status: an observational cohort study from China.

BACKGROUND: It is uncertain whether estimated remnant-like particle cholesterol (RLP-C) could predict residual risk in patients with different glycometabolic status. This study aimed to evaluate the relationship between estimated RLP-C and adverse prognosis in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) treated with percutaneous coronary intervention (PCI) and to identify the potential impact of glycometabolism on the predictive value of estimated RLP-C. METHODS: The study assessed 2419 participants with NSTE-ACS undergoing PCI at Beijing Anzhen Hospital from January to December 2015. Estimated RLP-C was calculated as follows: total cholesterol (TC) minus low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). The adverse events included all-cause death, non-fatal myocardial infarction (MI), and ischemia-driven revascularization. RESULTS: Estimated RLP-C was prominently associated with adverse prognosis in the total population [hazard ratio (HR) 1.291 per 1-SD increase, 95% confidence interval (CI) 1.119-1.490, P <  0.001], independent of confounding risk factors. However, subgroup analysis showed that increasing estimated RLP-C was related to a higher risk of adverse events in the diabetic population only [HR 1.385 per 1-SD increase, 95% CI 1.183-1.620, P <  0.001]. Estimated RLP-C failed to be a significant determinant of adverse prognosis in non-diabetic and pre-diabetic subgroups. The addition of estimated RLP-C to a baseline model including traditional risk factors enhanced the predictive performance both in total and diabetic populations. CONCLUSIONS: High estimated RLP-C level is a significant predictor for recurrent adverse events in patients with diabetes and NSTE-ACS treated with PCI.

Impacts of triglyceride-glucose index on prognosis of patients with type 2 diabetes mellitus and non-ST-segment elevation acute coronary syndrome: results from an observational cohort study in China.

BACKGROUND: The relationship between triglyceride-glucose index (TyG index) and the prevalence and prognosis of cardiovascular disease has been confirmed by former studies. However, it remains uncertain whether TyG index has a prognostic impact in patients with type 2 diabetes mellitus (T2DM) and non-ST-segment elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary intervention (PCI). METHODS: The study retrospectively enrolled 798 patients (mean age: 60.9 ± 8.3 years; 68.3% men) with T2DM and NSTE-ACS who underwent PCI at Beijing Anzhen Hospital from January to December 2015. TyG index was calculated as previously reported: ln [fasting TGs (mg/dL) * FBG (mg/dL)/2]. The primary endpoint was a composite of adverse events as follows: all-cause death, non-fatal myocardial infarction (MI) and ischemia-driven revascularization. RESULTS: TyG index was significantly higher in patients with a primary endpoint event compared with those without. Multivariate Cox proportional hazards analysis showed that 1-unit increase of TyG index was independently associated with higher risk of primary endpoint, independent of other risk factors [hazard ratio (HR) 3.208 per 1-unit increase, 95% confidence interval (CI) 2.400-4.289, P < 0.001]. The addition of TyG index to a baseline risk model had an incremental effect on the predictive value for adverse prognosis [AUC: baseline risk model, 0.800 vs. baseline risk model + TyG index, 0.856, P for comparison < 0.001; category-free net reclassification improvement (NRI) 0.346, P < 0.001; integrated discrimination improvement (IDI) 0.087, P < 0.001]. CONCLUSIONS: Increased TyG index is a significant predictor of adverse prognosis in patients with T2DM and NSTE-ACS undergoing PCI. Further studies need to be performed to determine whether interventions for TyG index have a positive impact on improving clinical prognosis.

Impacts of geriatric nutritional risk index on prognosis of patients with non-ST-segment elevation acute coronary syndrome: Results from an observational cohort study in China.

BACKGROUND AND AIMS: It is recognized that malnutrition increases risk of worse prognosis in patients with various diseases. The present study investigated if poor nutritional status predicts adverse outcomes in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS: The study enrolled 2299 patients (mean age: 60.01 ± 8.95 years; 71.8% male) with NSTE-ACS who underwent PCI at Beijing Anzhen Hospital from January to December 2015. The entire cohort was divided into training set (n = 1519) and testing set (n = 780) at a ratio of approximate 2 : 1. Nutritional status was assessed by geriatric nutritional risk index (GNRI). The primary endpoint was a composite of adverse events as follows: all-cause death, non-fatal myocardial infarction (MI) and any revascularization. Multivariate Cox analysis showed that GNRI significantly associated with primary endpoint, independent of other risk factors [hazard ratio (HR) 1.159 per 1-point decrease of GNRI, 95% confidence interval (CI) 1.130-1.189, p < 0.001]. The addition of GNRI to a baseline model had an incremental effect on the predictive value for adverse prognosis in training set [AUC: from 0.821 to 0.873, p < 0.001; category-free net reclassification improvement (NRI): 0.313, p < 0.001; integrated discrimination improvement (IDI): 0.108, p < 0.001]. The incremental effect of GNRI was further validated and confirmed in testing set. CONCLUSION: Lower GNRI is a significant predictor of adverse prognosis in patients with NSTE-ACS undergoing PCI. Further studies need to be performed to determine whether nutritional interventions have a positive impact on improving clinical prognosis.

Biological and Chemical Diversity of Marine Sponge-Derived Microorganisms over the Last Two Decades from 1998 to 2017.

Marine sponges are well known as rich sources of biologically natural products. Growing evidence indicates that sponges harbor a wealth of microorganisms in their bodies, which are likely to be the true producers of bioactive secondary metabolites. In order to promote the study of natural product chemistry and explore the relationship between microorganisms and their sponge hosts, in this review, we give a comprehensive overview of the structures, sources, and activities of the 774 new marine natural products from sponge-derived microorganisms described over the last two decades from 1998 to 2017.

Platelet-Derived Exosomes Affect the Proliferation and Migration of Human Umbilical Vein Endothelial Cells Via miR-126.

BACKGROUND: Intraplaque angiogenesis, the process of generating new blood vessels mediated by endothelial cells, contributes to plaque growth, intraplaque hemorrhage, and thromboembolic events. Platelet-derived Exosomes (PLT-EXOs) affect angiogenesis in multiple ways. The ability of miR-126, one of the best-characterized miRNAs that regulates angiogenesis, carried by PLT-EXOs to influence angiogenesis via the regulation of the proliferation and migration of endothelial cells is unknown. In this study, we aimed to investigate the effects of PLT-EXOs on angiogenesis by Human Umbilical Vein Endothelial Cells (HUVECs). METHODS: We evaluated the levels of miR-126 and angiogenic factors in PLT-EXOs from Acute Coronary Syndrome (ACS) patients and healthy donors by real-time Polymerase Chain Reaction (PCR) and western blotting. We incubated HUVECs with PLT-EXOs and measured cell proliferation and migration with the Cell Counting Kit-8 assay and scratch assay, respectively. We also investigated the expression of miR-126 and angiogenic factors in HUVECs after exposure to PLT-EXOs by western blotting and real-time PCR. RESULTS: PLT-EXOs from ACS patients contained higher levels of miR-126 and angiogenic factors, including Vascular Endothelial Growth Factor (VEGF), basic Fibroblast Growth Factor (bFGF), and Transforming Growth Factor Beta 1 (TGF-ß1), than those from healthy donors (p<0.05). Moreover, the levels of exosomal miR-126 and angiogenic factors were increased after stimulation with thrombin (p<0.01). HUVEC proliferation and migration were promoted by treatment with activated PLT-EXOs (p<0.01); they were accompanied by the over-expression of miR-126 and angiogenic factors, including VEGF, bFGF, and TGF-ß1 (p<0.01). CONCLUSION: Activated PLT-EXOs promoted the proliferation and migration of HUVECs, and the overexpression of miR-126 and angiogenic factors, thereby elucidating potential new therapeutic targets for intraplaque angiogenesis.

Highly Efficient Formal [2+2+2] Strategy for the Rapid Construction of Polycyclic Spiroindolines: A Concise Synthesis of 11-Demethoxy-16-epi-myrtoidine.

A novel formal [2+2+2] strategy for the stereoselective elaboration of polycyclic indole alkaloids is described. Upon treatment with the catalyst InCl3 (5 mol %), tryptamine-derived enamides reacted readily with methylene malonate, thus enabling rapid and gram-scale access to versatile tetracyclic spiroindolines with excellent diastereoselectivity (21 examples, up to 95 % yield, up to d.r.>95:5). This strategy provides a concise approach to alkaloids isolated from Strychnos myrtoides, as demonstrated by a short synthesis of 11-demethoxy-16-epi-myrtoidine.