Predictors of futile recanalization after endovascular treatment of acute ischemic stroke.

OBJECTIVE: Endovascular therapy (EVT) is the most successful treatment for patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO) in the anterior circulation. However, futile recanalization (FR) seriously affects the prognosis of these patients. The aim of this study was to investigate predictors of FR after EVT in patients with AIS. METHOD: Patients diagnosed with AIS due to anterior circulation LVO and receiving EVT between June 2020 and October 2022 were prospectively enrolled. FR after EVT was defined as a poor 90-day prognosis (modified Rankin Scale [mRS] score ≥ 3) despite achieving successful reperfusion (modified Thrombolysis in Cerebral Infarction [mTICI] classification of 2b-3). All included patients were categorized into control group (mRS score < 3) and FR group (mRS score ≥ 3). Demographic characteristics, comorbidities (hypertension, diabetes, atrial fibrillation, smoking, etc.), stroke-specific data (NIHSS score, ASPECT score and site of occlusion), procedure data (treatment type [direct thrombectomy vs. bridging thrombectomy], degree of vascular recanalization [mTICI], procedure duration time and onset-recanalization time), laboratory indicators (lymphocytes count, neutrophils count, monocytes count, C-reactive protein, neutrophil-to-lymphocyte ratio [NLR], monocyte-to-high-density lipoprotein ratio [MHR], lymphocyte-to-monocyte ratio [LMR], lymphocyte-to-C-reactive protein ratio [LCR], lymphocyte-to-high-density lipoprotein ratio[LHR], total cholesterol and triglycerides.) were compared between the two groups. Multivariate logistic regression analysis was performed to explore independent predictors of FR after EVT. RESULTS: A total of 196 patients were included in this study, among which 57 patients were included in the control group and 139 patients were included in the FR group. Age, proportion of patients with hypertension and diabetes mellitus, median NIHSS score, CRP level, procedure duration time, neutrophil count and NLR were higher in the FR group than in the control group. Lymphocyte count, LMR, and LCR were lower in the FR group than in the control group. There were no significant differences in platelet count, monocytes count, total cholesterol, triglycerides, HDL, LDL, gender, smoking, atrial fibrillation, percentage of occluded sites, onset-recanalization time, ASPECT score and type of treatment between the two groups. Multivariate logistic regression analysis demonstrated that NLR was independently associated with FR after EVT (OR = 1.37, 95%CI = 1.005-1.86, P = 0.046). CONCLUSION: This study demonstrated that high NLR was associated with a risk of FR in patients with AIS due to anterior circulation LVO. These findings may help clinicians determine which patients with AIS are at higher risk of FR after EVT. Our study can provide a theoretical basis for interventions in the aforementioned population.

Purinergic signaling: a potential therapeutic target for ischemic stroke.

Pathogenesis of ischemic stroke is mainly characterized by thrombosis and neuroinflammation. Purinergic signaling pathway constitutes adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), and adenosine (ADO). ATP is hydrolyzed to ADP and then to AMP by extracellular nucleotidase CD39; AMP is subsequently converted to adenosine by CD73. All these nucleotides and nucleosides act on purinergic receptors protecting against thrombosis and inhibit inflammation. In addition, many physical methods have been found to play a neuroprotective role through purinergic signaling. This review mainly introduces the role and potential mechanism of purinergic signalings in the treatment of ischemic stroke, so as to provide reference for seeking new treatment methods for stroke.

Direct Thrombectomy versus Bridging Thrombectomy within 6 Hours of Stroke Onset: A Prospective Cohort Study on Cognitive and Physical Function Outcomes.

PURPOSE: To evaluate the physical and cognitive functions of patients with stroke who underwent either direct or bridging thrombectomy within 6 hours of stroke onset. MATERIALS AND METHODS: Patients with large vessel occlusion in anterior circulation treated with direct (direct group) or bridging thrombectomy (bridging group) were prospectively analyzed between June 2020 and February 2022. The efficacy outcome was the 3-month modified Rankin Scale (mRS) score, the safety outcome was symptomatic intracranial hemorrhage (sICH), and cognitive function was assessed using the Clinical Dementia Rating (CDR) scale at 6 months after stroke. RESULTS: A total of 125 patients (direct group, n = 75; bridging group, n = 50) who had completed follow-up at 3 months by telephone call were included. No significant differences were observed between the direct and bridging groups in terms of an mRS score of 0-2 (25.3% vs 22.0%, respectively; P = .83), an mRS score of 0-3 (37.3% vs 44.0%, respectively; P = .58), sICH (17.3% vs 14.0%, respectively; P = .80), or 3-month all-cause mortality (36.3% vs 30.0%, respectively; P = .34). Sixty-nine patients (direct group, n = 38; bridging group, n = 31) completed the CDR assessment at 6 months after stroke. There was no significant difference in poststroke dementia, defined as a CDR score of ≥1 point between the direct group (42.1%) and bridging group (22.6%) (P = .12). Ordinal regression analyses showed that the CDR score at 6 months was not associated with treatment type (direct thrombectomy vs bridging thrombectomy). CONCLUSIONS: With regard to physical and cognitive functions at 3 and 6 months, direct thrombectomy was comparable with bridging thrombectomy in patients who were treated within 6 hours of stroke onset.

Predictive role of pre-thrombolytic hs-CRP on the safety and efficacy of intravenous thrombolysis in acute ischemic stroke.

PURPOSE: To investigate the predictive role of pre-thrombolytic high sensitivity C-reactive protein (hs-CRP) on the safety and efficacy of intravenous thrombolysis in patients with acute ischemic stroke (AIS). METHODS: Patients with AIS who underwent intravenous thrombolysis with recombinant plasminogen activator (rtPA) or urokinase without endovascular therapy from June 2019 to June 2022 were retrospectively analysed. All patients were grouped into two groups (high or low hs-CRP group) according to the median value of hs-CRP before intravenous thrombolysis. The baseline NIHSS, NIHSS changes before and after thrombolysis (ΔNIHSS), the rate of good thrombolysis response (NIHSS decreased ≥ 2 points from baseline), the rate of any intracranial hemorrhage, age, sex, hypertension, diabetes, uric acid and platelet count were compared between the two groups. Logistic regression analysis was performed to identify possible prognostic factors for a good thrombolysis response. RESULTS: A total of 212 patients were included in the analysis, with a mean age of 66.3 ± 12.5 years. In total, 145 patients received rtPA, and 67 patients received urokinase. Patients were divided into a high hs-CRP group (> 1.60 mg/L) and a low hs-CRP group (≤ 1.60 mg/L) according to the median hs-CRP level (1.60 mg/L). The ΔNIHSS of the high hs-CRP group was significantly smaller than that of the low hs-CRP group (0 [-1 ~ 0] vs. -1 [-2 ~ 0], P < 0.05). The good rate of thrombolysis response in the high hs-CRP group was significantly lower than that in the low hs-CRP group (21.9% vs. 36.5%, P < 0.05). Similar results were shown in the rtPA subgroup between the high and low hs-CRP groups but not in the urokinase subgroup. Logistic regression analysis showed that hs-CRP > 1.60 mg/L was negatively correlated with a good thrombolysis response rate (OR = 0.496, 95% CI = 0.266-0.927, P = 0.028). CONCLUSION: hs-CRP > 1.6 mg/L may serve as a poor prognosis predictive factor for patients with AIS receiving intravenous thrombolysis. However, due to the small sample size of this study, further studies are needed to verify our results.

Oleanolic acid attenuates TGF-ß1-induced epithelial-mesenchymal transition in NRK-52E cells.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) plays an important role in the progression of renal interstitial fibrosis, which finally leads to renal failure. Oleanolic acid (OA), an activator of NF-E2-related factor 2 (Nrf2), is reported to attenuate renal fibrosis in mice with unilateral ureteral obstruction. However, the role of OA in the regulation of EMT and the underlying mechanisms remain to be investigated. This study aimed to evaluate the effects of OA on EMT of renal proximal tubular epithelial cell line (NRK-52E) induced by TGF-ß1, and to elucidate its underlying mechanism. METHODS: Cells were incubated with TGF-ß1 in the presence or absence of OA. The epithelial marker E-cadherin, the mesenchymal markers, α-smooth muscle actin (α-SMA), fibronectin, Nrf2, klotho, the signal transducer (p-Smad2/3), EMT initiator (Snail), and ILK were assayed by western blotting. RESULTS: Our results showed that the NRK-52E cells incubated with TGF-ß1 induced EMT with transition to the spindle-like morphology, down-regulated the expression of E-cadherin but up-regulated the expression of α-SMA and fibronectin. However, the treatment with OA reversed all EMT markers in a dose-dependent manner. OA also restored the expression of Nrf2 and klotho, decreased the phosphorylation of Smad2/3, ILK, and Snail in cells which was initiated by TGF-ß1. CONCLUSION: OA can attenuate TGF-ß1 mediate EMT in renal tubular epithelial cells and may be a promising therapeutic agent in the treatment of renal fibrosis.

[Structural components of Chinese medicine and pharmacology network: systematical overall regulation on pathological network].

Development of the disease is the result of several factors involved in biological network changes. The nature of drug intervention is to regulate these pathological changes to the normal range. Advantages of traditional Chinese medicine (TCM) are to integrally and systematically regulate this biological networks and systematic pathology through multi-targets, multi-levels, multi-channels. Structural components TCM provides the controlled and precise basis "substance" for this regulation and also to clarify the "truth" of the nature of the regulation by the network pharmacology. Network pharmacology provides new strategy for the research on mechanism of structural components TCM. This study not only reflects the overall characteristics of the development of the disease, but also fully embodies the essence of TCM for preventing and treating diseases through changing traditional model on "one drug, one gene, one disease". This paper explores systematically the integration essence, features and research strategies of structural components TCM and the network pharmacology, understand the interaction of structural components TCM and body from the perspective of the overall concept of improving or restoring the balance of.biological networks. It is effective measure to reveal the structure of a multi-component for regulating biological networks mechanisms, and also provide new ideas and methods for further scientific research and innovation of structural component TCM.

[Research development of the chemical material basis of Alisma orientalis and its toxicity].

Alisma orientalis is a traditional herb medicine commonly used in clinical. With the increasing report of its toxicity in clinical, the renal toxicity of Alisma orientalis has got gradually attention. This paper systematically reviews the research on the chemical material basis of Alisma orientalis including its chemical composition and toxicity of ingredients; and also declares its toxic ingredients and targets according to Network toxicology. Based on the controversy on renal toxicity of Alisma orientalis, we analyzed the possible reasons that may be associated with renal toxicity. It might be associated with the differences of the material basis composition and regulatory toxicology network, differences in employed processing technology, the metabolic function leading to accumulation of compounds, dosage and duration of the experiment and compatibility. The review provides possible reference and ideas for the quality control and rational use of Alisma orientalis.

Profiling the metabolism of astragaloside IV by ultra performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry.

Astragaloside IV is a compound isolated from the Traditional Chinese Medicine Astragalus membranaceus, that has been reported to have bioactivities against cardiovascular disease and kidney disease. There is limited information on the metabolism of astragaloside IV, which impedes comprehension of its biological actions and pharmacology. In the present study, an ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS)-based approach was developed to profile the metabolites of astragaloside IV in rat plasma, bile, urine and feces samples. Twenty-two major metabolites were detected. The major components found in plasma, bile, urine and feces included the parent chemical and phases I and II metabolites. The major metabolic reactions of astragaloside IV were hydrolysis, glucuronidation, sulfation and dehydrogenation. These results will help to improve understanding the metabolism and reveal the biotransformation profiling of astragaloside IV in vivo. The metabolic information obtained from our study will guide studies into the pharmacological activity and clinical safety of astragaloside IV.

[Research thoughts and technology system framework of jinfukang oral liquid secondary exploitation].

Most Chinese medicine has good clinical efficacy and application. However, the material basis is vague for the lack of basic research, the value of Chinese medicine is hard to reflect for the low technology level and product quality is difficult to maintain for the quality control indicator selection is incorrect. Chinese medicine Jinfukang oral liquid is a typical product of Chinese medicines. Jinfukang oral liquid was selected as a model drug in this article. Based on the overall concept and systems theory of traditional Chinese medicine, the research idea and technology system for modern Chinese medicine secondary exploitation was formed. The system includes three parts, for the first, basic research to make clear the components structure and their action mechanism, for the second, technology upgraded to optimize process and improve the product quality, for the last, exploring the associated industry to form the industrial chain. The research ideas and technology system based on the material basis research and development of modern Chinese medicine, guided with component structure in Chinese medicine and aimed clinical needs. This research ideas and technology system provides strategies and methods for the development of modern Chinese medicine secondary exploitation.

[Establishment of industry promotion technology system in Chinese medicine secondary exploitation based on "component structure theory"].

The purpose of the secondary exploitation of Chinese medicine is to improve the quality of Chinese medicine products, enhance core competitiveness, for better use in clinical practice, and more effectively solve the patient suffering. Herbs, extraction, separation, refreshing, preparation and quality control are all involved in the industry promotion of Chinese medicine secondary exploitation of industrial production. The Chinese medicine quality improvement and industry promotion could be realized with the whole process of process optimization, quality control, overall processes improvement. Based on the "component structure theory", "multi-dimensional structure & process dynamic quality control system" and systematic and holistic character of Chinese medicine, impacts of whole process were discussed. Technology systems of Chinese medicine industry promotion was built to provide theoretical basis for improving the quality and efficacy of the secondary development of traditional Chinese medicine products.

[Establishment of prescription research technology system in Chinese medicine secondary exploitation based on "component structure" theory].

Chinese medicine prescriptions are the wisdom outcomes of traditional Chinese medicine (TCM) clinical treatment determinations which based on differentiation of symptoms and signs. Chinese medicine prescriptions are also the basis of secondary exploitation of TCM. The study on prescription helps to understand the material basis of its efficacy, pharmacological mechanism, which is an important guarantee for the modernization of traditional Chinese medicine. Currently, there is not yet dissertation n the method and technology system of basic research on the prescription of Chinese medicine. This paper focuses on how to build an effective system of prescription research technology. Based on "component structure" theory, a technology system contained four-step method that "prescription analysis, the material basis screening, the material basis of analysis and optimization and verify" was proposed. The technology system analyzes the material basis of the three levels such as Chinese medicine pieces, constituents and the compounds which could respect the overall efficacy of Chinese medicine. Ideas of prescription optimization, remodeling are introduced into the system. The technology system is the combination of the existing research and associates with new techniques and methods, which used for explore the research thought suitable for material basis research and prescription remodeling. The system provides a reference for the secondary development of traditional Chinese medicine, and industrial upgrading.

[Construction of research system for processing mechanism of traditional Chinese medicine based on chemical composition transformation combined with intestinal absorption barrier].

Based on practice of Epimedium processing mechanism for many years and integrated multidisciplinary theory and technology, this paper initially constructs the research system for processing mechanism of traditional Chinese medicine based on chemical composition transformation combined with intestinal absorption barrier, which to form an innovative research mode of the " chemical composition changes-biological transformation-metabolism in vitro and in vivo-intestinal absorption-pharmacokinetic combined pharmacodynamic-pharmacodynamic mechanism". Combined with specific examples of Epimedium and other Chinese herbal medicine processing mechanism, this paper also discusses the academic thoughts, research methods and key technologies of this research system, which will be conducive to systematically reveal the modem scientific connotation of traditional Chinese medicine processing, and enrich the theory of Chinese herbal medicine processing.

Predictive Role of Pre-Thrombolytic Neutrophil-Platelet Ratio on Hemorrhagic Transformation After Intravenous Thrombolysis in Acute Ischemic Stroke.

To investigate the predictive role of the neutrophil-platelet ratio (NPR) before intravenous thrombolysis (IVT) on hemorrhagic transformation (HT) in patients with acute ischemic stroke (AIS). AIS patients treated with IVT without endovascular therapy between June 2019 and February 2023 were included. Patients were divided into high NPR (>35) and low NPR (≤35) groups according to the optimal threshold NPR value for identifying high-risk patients before IVT. The baseline data and the incidence of HT and symptomatic intracranial hemorrhage (sICH) were compared between the two groups. The predictive role of the NPR and other related factors on HT after IVT was analyzed by multivariate logistic regression. A total of 247 patients were included, with an average age of 67.5 ± 12.4 years. Post-thrombolytic HT was observed in 18.6% of the patients, and post-thrombolytic sICH was observed in 1.2% of the patients. There were 69 patients in the high NPR group and 178 patients in the low NPR group. The incidence of HT in the high NPR group was significantly higher than that in the low NPR group (30.4% vs 16.3%, P < .05). The incidence of sICH was significantly higher in the high NPR group than in the low NPR group (14.5% vs 1.7%, P < .001). Multivariate logistic regression analysis showed that NPR > 35 was positively correlated with HT (odds ratio (OR) = 3.236, 95% confidence interval (CI): 1.481-7.068, P = .003) and sICH (OR = 13.644, 95% CI: 2.392-77.833, P = .003). A high NPR (>35) before IVT may be a predictor of HT in AIS patients. This finding may help clinicians make clinical decisions before IVT in AIS patients.

[Study thought of material basis of secondary development of major traditional Chinese medicine varieties on basis of combination of in vivo and in vitro experiments].

The secondary development of major traditional Chinese medicine varieties is one of important links during the modernization, scientification and standardization of traditional Chinese medicines. How to accurately and effectively identify the pharmacodynamic material basis of original formulae becomes the primary problem in the secondary development, as well as the bottleneck in the modernization development of traditional Chinese medicines. On the basis of the existing experimental methods, and according to the study thought that the multi-component and complex effects of traditional Chinese medicine components need to combine multi-disciplinary methods and technologies, we propose the study thought of the material basis of secondary development of major traditional Chinese medicine varieties based on the combination of in vivo and in vitro experiments. It is believed that studies on material basis needs three links, namely identification, screening and verification, and in vivo and in vitro study method corresponding to each link is mutually complemented and verified. Finally, the accurate and reliable material basis is selected. This thought provides reference for the secondary development of major traditional Chinese medicine varieties and studies on compound material basis.

[Thinking of study on secondary development of major traditional Chinese medicine varieties based on system theory].

The secondary development of traditional Chinese medicines (TCMs) is an important content of TCM modernization process, as well as an important path for developing new TCM drugs. Under the guidance of the system theory, in response to the lack of the overall guideline and practical methods for the secondary development of TCMs at present, we introduced the overall thought of the secondary development of major TCM varieties, as well as the roles and contents of clinical research, pharmacology and pharmaceutics in the process of the secondary development of major TCM varieties, so as to provide systematic strategies and methods for the development of major TCM varieties.

Cerebral blood volume index can predict the long-term prognosis after endovascular thrombectomy in patients with acute ischemic stroke due to large vessel occlusion.

Long-term prognosis and factors influencing endovascular therapy (EVT) remain unclear. This study aimed to investigate the association between computed tomography perfusion (CTP) parameters and long-term prognosis of patients with acute ischemic stroke (AIS) treated with EVT. Patients with AIS due to large vessel occlusion treated with EVT were prospectively included for a 1-year follow-up. All patients and their data were grouped based on the hypoperfusion intensity ratio (HIR, ＜0.3 vs. ≥ 0.3) and cerebral blood volume (CBV) index (＞0.7 vs. ≤ 0.7). The primary outcome was favorable prognosis, defined as a modified Rankin Scale (mRS) score of 0-2. Multivariate logistic regression was used to analyze factors influencing long-term favorable prognosis. Of 69 patients included, 35 (50.7 %) achieved mRS 0-2 at one year. A favorable prognosis was observed predominantly in patients with higher CBV index (75.0 % vs. 34.1 %, p= 0.001) and lower HIR (72.0 % vs. 38.6 %, p=0.008). In the multivariate logistic regression, CBV index (odds ratio (OR) = 4.362; 95 % confidence interval (CI): 1.052, 18.082; p = 0.042), baseline National Institutes of Health Stroke Scale (NIHSS) score (OR = 0.913; 95 % CI: 0.836, 0.997; p = 0.044), and symptomatic intracranial hemorrhage (sICH) (OR = 0.089; 95 % CI: 0.009, 0.925; p = 0.043) were independently associated with a long-term favorable prognosis. The CBV index may serve as a predictor of the long-term prognosis of patients treated with EVT. The novel finding is that the baseline NIHSS score and sICH were associated with long-term prognosis.

Cerebral blood volume index may be a predictor of independent outcome of thrombectomy in stroke patients with low ASPECTS.

INTRODUCTION: To evaluate the predictors for efficacy and safety of patients with acute ischemic stroke (AIS) and Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) ＜6 undergoing endovascular therapy (EVT). METHODS: This study retrospectively analyzed consecutive patients presented between December 2020 and December 2021 with large vessel occlusions (LVO) within the anterior circulation and an ASPECTS ＜6, followed by EVT. The efficacy outcome was 90-day functional independence, defined as modified Rankin Scale (mRS) score 0-3. The primary safety outcome was symptomatic intracranial hemorrhage (sICH). Secondary safety outcomes included 90-day all-cause mortality and 24-hour any ICH. RESULTS: A total of 22 patients were included. The percentage of patients with mRS 0-3 at 90 days was 36.4% (8/22). The occurrence of sICH was 22.7% (5/22). The occurrence of any ICH was 45.5% (10/22). The 90-day all-cause mortality was 36.4% (8/22). Median (interquartile range, IQR) cerebral blood volume (CBV) index was 0.5 (0.4-0.7). CBV index in mRS 0-3 group (n = 8) was higher than mRS 4-5 group (n = 14) (P＜0.05). There was no significant difference of age, gender, comorbidities, baseline National Institutes of Health Stroke Scale (NIHSS) score, mismatch ratio, CBV index, interval between stroke onset and re-perfusion, good re-perfusion rate between sICH group (n = 5) and non-sICH group (n = 17). CONCLUSIONS: AIS patients with low ASPECTS can still benefit from EVT and gain good functional outcome, especial those had higher CBV index on pre-EVT computed tomography perfusion (CTP). Further studies with larger sample size are needed to validate our findings.

LncRNA-H19 induces hepatic stellate cell activation via upregulating alcohol dehydrogenase III-mediated retinoic acid signals.

Activation of hepatic stellate cells (HSCs) is a pivotal event in liver fibrosis, characterized by enhanced retinoic acid signals. Although up-regulated retinoic acid signal responds further to maintain HSC activation, the underlying molecular mechanisms are largely unknown. In this study, we sought to investigate the role of lncRNA-H19 in regulation of retinoic acid signals, and to further examine the underlying mechanism in this molecular context. We found that lncRNA-H19 upregulation could enhance retinoic acid signals to induce HSC activation, whereas lncRNA-H19 knockdown completely disturbed retinoic acid signals. Moreover, the activation of retinoic acid signals impaired the lncRNA-H19 knockdown mediated HSC inactivation. Interestingly, we also found that enhanced retinoic acid signals by lncRNA-H19 was associated with a coordinate increase in retinol metabolism during HSC activation. Increased retinol metabolism contributed to obvious lipid droplet consumption. Importantly, we identified that alcohol dehydrogenase III (ADH3) was essential for lncRNA-H19 to enhance retinoic acid signals. The inhibition of ADH3 completely abrogated the lncRNA-H19 mediated retinoic acid signals and HSC activation. Of note, we identified dihydroartemisinin (DHA) as a natural inhibitor for lncRNA-H19. Treatment with DHA significantly decreased the expression of lncRNA-H19, reduced the expression of ADH3, blocked retinoic acid signals, and in turn, inhibited HSC activation. Overall, these results provided novel implications to reveal the molecular mechanism of increased retinoic acid signals during HSC activation, and identify lncRNA-H19/ADH3 pathway as a potential target for the treatment of liver fibrosis.

[Pharmacokinetics of pueraria flavonoids from Pueraria lobata by anti-oxidant pharmacodynamics effect method].

OBJECTIVE: To study the pharmacokinetics of pueraria flavonoids(PF) from Pueraria lobata. METHOD: An anti-oxidant pharmacodynamics effect method was quoted to detect the antioxidant ability of PF contained in rats plasm after oral delivered, measures the fluorescence intensity, and calculates the concentration of components in plasma, then we can get the plot of the change of the content of PF contained in rats plasm, and then we can get the pharmacokinetics of Pueraria Flavonoids pellets. RESULT: The AUC of Pueraria lobata isoflavone pellets is 4.40-fold of Yufengningxin tablets. CONCLUSION: It can enhance the bioavailability of PF by made it to pellets.

[Non-LTR retrotransposons: LINEs and SINEs in plant genome].

Retrotransposons are one of the drivers of genome evolution. They include LTR (long terminal repeat) retrotransposons, which widespread in Eukaryotagenomes, show structural similarity to retroviruses. Non-LTR retrotransposons were first discovered in animal genomes and then identified as ubiquitous components of nuclear genomes in many species across the plant kingdom. They constitute a large fraction of the repetitive DNA. Non-LTR retrotransposons are divided into LINEs (long interspersed nuclear elements) and SINEs (short interspersed nuclear elements). Transposition of non-LTR retrotransposons is rarely observed in plants indicating that most of them are inactive and/or under regulation of the host genome. Transposition is poorly understood, but experimental evidence from other genetic systems shows that LINEs are able to transpose autonomously while non-autonomous SINEs depend on the reverse transcription machinery of other retrotransposons. Phylogenic analysis shows LINEs are probably the most ancient class of retrotransposons in plant genomes, while the origin of SINEs is unknown. This review sums up the above data and wants to show readers a clear picture of non-LTR retrotransposons.