Differentiation of oligodendrocyte progenitor cells into mature myelin-forming oligodendrocytes contributes to remyelination.Failure of remyelination due to oligodendrocyte progenitor cell death can result in severe n...Differentiation of oligodendrocyte progenitor cells into mature myelin-forming oligodendrocytes contributes to remyelination.Failure of remyelination due to oligodendrocyte progenitor cell death can result in severe nerve damage.Ferroptosis is an iron-dependent form of regulated cell death caused by membrane rupture induced by lipid peroxidation,and plays an important role in the pathological process of ischemic stroke.However,there are few studies on oligodendrocyte progenitor cell ferroptosis.We analyzed transcriptome sequencing data from GEO databases and identified a role of ferroptosis in oligodendrocyte progenitor cell death and myelin injury after cerebral ischemia.Bioinformatics analysis suggested that perilipin-2(PLIN2)was involved in oligodendrocyte progenitor cell ferroptosis.PLIN2 is a lipid storage protein and a marker of hypoxia-sensitive lipid droplet accumulation.For further investigation,we established a mouse model of cerebral ischemia/reperfusion.We found significant myelin damage after cerebral ischemia,as well as oligodendrocyte progenitor cell death and increased lipid peroxidation levels around the infarct area.The ferroptosis inhibitor,ferrostatin-1,rescued oligodendrocyte progenitor cell death and subsequent myelin injury.We also found increased PLIN2 levels in the peri-infarct area that co-localized with oligodendrocyte progenitor cells.Plin2 knockdown rescued demyelination and improved neurological deficits.Our findings suggest that targeting PLIN2 to regulate oligodendrocyte progenitor cell ferroptosis may be a potential therapeutic strategy for rescuing myelin damage after cerebral ischemia.展开更多
Accumulating evidence has demonstrated the involvement of B cells in neuroinflammation and neuroregeneration.However,the role of B cells in ischemic stroke remains unclear.In this study,we identified a novel phenotype...Accumulating evidence has demonstrated the involvement of B cells in neuroinflammation and neuroregeneration.However,the role of B cells in ischemic stroke remains unclear.In this study,we identified a novel phenotype of macrophage-like B cells in brain-infiltrating immune cells expressing a high level of CD45.Macrophage-like B cells chara cterized by co-expression of B-cell and macrophage markers,showed stronger phagocytic and chemotactic functions compared with other B cells and showed upregulated expression of phagocytosis-related genes.Gene Ontology analysis found that the expression of genes associated with phagocytosis,including phagosome-and lysosome-related genes,was upregulated in macrophage-like B cells.The phagocytic activity of macrophage-like B cells was ve rified by immunostaining and three-dimensional reconstruction,in which TREM2-labeled macrophage-like B cells enwrapped and internalized myelin debris after cerebral ischemia.Cell-cell interaction analysis revealed that macrophage-like B cells released multiple chemokines to recruit peripheral immune cells mainly via CCL pathways.Single-cell RNA sequencing showed that the transdiffe rentiation to macrophage-like B cells may be induced by specific upregulation of the transcription factor CEBP fa mily to the myeloid lineage and/or by downregulation of the transcription factor Pax5 to the lymphoid lineage.Furthermore,this distinct B cell phenotype was detected in brain tissues from mice or patients with traumatic brain injury,Alzheimer’s disease,and glioblastoma.Overall,these results provide a new perspective on the phagocytic capability and chemotactic function of B cells in the ischemic brain.These cells may serve as an immunotherapeutic target for regulating the immune response of ischemic stroke.展开更多
The outcome of early intravenous thrombolysis for ischemic stroke in patients with atrial fibrillation（AF）is worse than that without thrombosis. How to increase the efficacy of intravenous thrombolysis for AF-relate...The outcome of early intravenous thrombolysis for ischemic stroke in patients with atrial fibrillation（AF）is worse than that without thrombosis. How to increase the efficacy of intravenous thrombolysis for AF-related ischemic stroke remains largely unknown. In this study, we investigated factors that influence the effect of intravenous thrombolysis in these patients. Our results showed that thrombolysis was independently associated with a favorable outcome（P ／ 0.001） and did not influence the mortality of AF-related ischemic stroke, although it increased the risk of hemorrhage within 24 h after treatment. Risk factors for a poor outcome at admission were：heart failure（P = 0.045）; high systolic pressure（P = 0.039）; high blood glucose（P = 0.030）; and a high National Institutes of Health Stroke Scale（NIHSS） score（P ／ 0.001）. Moreover, high systolic pressure at admission（P = 0.007）, high blood glucose（P = 0.027）, and a high NIHSS score（P ／ 0.001） were independent risk factors for mortality at 3 months. Besides thrombolysis, a high NIHSS score（P = 0.006） and warfarin taken within 48 h before stroke onset（P = 0.032） were also independent risk factors for symptomatic hemorrhage within 24 h after treatment. Ischemic stroke patients with AF benefited from intravenous thrombolysis with recombinant tissue plasminogen activator within 4.5 h after stroke.展开更多
During the hyperacute phase of intracerebral hemorrhage(ICH),the mass effect and blood components mechanically lead to brain damage and neurotoxicity.Our findings revealed that the mass effect and transferrin precipit...During the hyperacute phase of intracerebral hemorrhage(ICH),the mass effect and blood components mechanically lead to brain damage and neurotoxicity.Our findings revealed that the mass effect and transferrin precipitate neuronal oxidative stress and iron uptake,culminating in ferroptosis in neurons.M6A(N6-methyladenosine)modification,the most prevalent mRNA modification,plays a critical role in various cell death pathways.The Fto(fat mass and obesity-associated protein)demethylase has been implicated in numerous signaling pathways of neurological diseases by modulating m6A mRNA levels.Regulation of Fto protein levels in neurons effectively mitigated mass effect-induced neuronal ferroptosis.Applying nanopore direct RNA sequencing,we identified voltage-dependent anion channel 3(Vdac3)as a potential target associated with ferroptosis.Fto influenced neuronal ferroptosis by regulating the m6A methylation of Vdac3 mRNA.These findings elucidate the intricate interplay between Fto,Vdac3,m6A methylation,and ferroptosis in neurons during the hyperacute phase post-ICH and suggest novel therapeutic strategies for ICH.展开更多
The role of glial scar after intracerebral hemorrhage(ICH)remains unclear.This study aimed to investigate whether microglia-astrocyte interaction affects glial scar formation and explore the specific function of glial...The role of glial scar after intracerebral hemorrhage(ICH)remains unclear.This study aimed to investigate whether microglia-astrocyte interaction affects glial scar formation and explore the specific function of glial scar.We used a pharmacologic approach to induce microglial depletion during different ICH stages and examine how ablating microglia affects astrocytic scar formation.Spatial transcriptomics(ST)analysis was performed to explore the potential ligand-receptor pair in the modulation of microglia-astrocyte interaction and to verify the functional changes of astrocytic scars at different periods.During the early stage,sustained microglial depletion induced disorganized astrocytic scar,enhanced neutrophil infiltration,and impaired tissue repair.ST analysis indicated that microglia-derived insulin like growth factor 1(IGF1)modulated astrocytic scar formation via mechanistic target of rapamycin(mTOR)signaling activation.Moreover,repopulating microglia(RM)more strongly activated mTOR signaling,facilitating a more protective scar formation.The combination of IGF1 and osteopontin(OPN)was necessary and sufficient for RM function,rather than IGF1 or OPN alone.At the chronic stage of ICH,the overall net effect of astrocytic scar changed from protective to destructive and delayed microglial depletion could partly reverse this.The vital insight gleaned from our data is that sustained microglial depletion may not be a reasonable treatment strategy for early-stage ICH.Inversely,early-stage IGF1/OPN treatment combined with late-stage PLX3397 treatment is a promising therapeutic strategy.This prompts us to consider the complex temporal dynamics and overall net effect of microglia and astrocytes,and develop elaborate treatment strategies at precise time points after ICH.展开更多
Background and Purpose -Although white matter is a potential target of acute stroke therapy, there is uncertainty about its relative resistance to ischemia and whether it is capable of mounting a penumbral response. T...Background and Purpose -Although white matter is a potential target of acute stroke therapy, there is uncertainty about its relative resistance to ischemia and whether it is capable of mounting a penumbral response. To explore these issues further, we examined the differential effects of ischemia on gray and white matter using magnetic resonance (MR) perfusion-diffusion mismatch after acute stroke. Methods -MR imaging studies were performed within 12 hours in patients with initial hemispheric ischemic stroke. “At-risk”tissue was defined as tissue with abnormal diffusion-weighted imaging/perfusion-weight imaging or infarcti on on follow-up image. Tissue was segmented using a probabilistic atlas generat ed from age-matched controls. The proportions of “at-risk”tissue, which was penumbral at the time of imaging, were compared between gray and white matter. R esults -Thirty-two patients had diffusion-perfusion mismatched penumbral tiss ue present in both gray and white matter compartments. Although the absolute mis match volumes were greater in gray (median 42 cm3, interquartile range 18 to 70 cm3)than in white matter (39 cm3, 17 to 49 cm3;P < 0.001), the proportion of “a t-risk”tissue, which was penumbral at the time of imaging (median 3.7 hours, r ange 1.5 to 9.9 hours) was greater in white (69%, 49%to 86%) than gray matter (62%, 52%to 75%; P=0.026). However, the proportions spontaneously salvaged b y 3 months were similar in both compartments. Conclusions -These findings are c onsistent with white matter being able to mount an ischemic penumbral response i n humans and being more resistant to cerebral ischemia than gray matter. They al so raise the possibility that the therapeutic window is longer for white matter and may require alternative therapeutic strategies.展开更多
A contributing factor to the failure of trials of neuroprotectants in acute ischemic stroke may be the differing vulnerability to ischemia of white compared with gray matter. To address this issue, we determined to es...A contributing factor to the failure of trials of neuroprotectants in acute ischemic stroke may be the differing vulnerability to ischemia of white compared with gray matter. To address this issue, we determined to establish the existence of potentially viable tissue in white matter and its evolution to infarction or salvage in both gray and white matter compartments in patients with ischemic stroke. Twenty- seven patients (mean age, 73.4 years) at a median of 16.5 hours after symptom onset were studied using the hypoxic marker 18F- misonidazole with positron emission tomography (PET). Tissue was segmented using an magnetic resonance probabilistic map. Although there was a greater volume of initially “ at- risk tissue” in gray matter (58.3cm3, 29.9- 93.0cm3) than white matter (42.0cm 3, 15.8- 74.0cm3;p < 0.001) at the time of PET imaging, a higher proportion of this was still potentially viable in white matter (41.4% , 4.6- 74.5% ) than in gray matter (23.6% , 3.2- 61.1% ; p < 0.05). However, a similar proportion in each compartment spontaneously survived. These data provide evidence for the existence of potentially salvageable tissue in human white matter and is consistent with it having a similar or even greater resistance to ischemia than gray matter. For the latter possibility, alternative therapeutic strategies may be required for its salvage.展开更多
Clinicians often have to make treatment decisions based on the likelihood that an individual patient will benefit. In this article we consider the relevance of relative and absolute risk reductions, and draw attention...Clinicians often have to make treatment decisions based on the likelihood that an individual patient will benefit. In this article we consider the relevance of relative and absolute risk reductions, and draw attention to the importance of expressing the results of trials and subgroup analyses in terms of absolute risk. We describe the limitations of univariate subgroup analysis in situations in which there are several determinants of treatment effect, and review the potential for targeting treatments with risk models, especially when benefit is probably going to be dependent on the absolute risk of adverse outcomes with or without treatment. The ability to systematically take into account the characteristics of an individual patient and their interactions, to consider the risks and benefits of interventions separately if needed, and to provide patients with person alised estimates of their likelihood of benefit is shown using the example of endarterectomy for symptomatic carotid stenosis.展开更多
Background and Purpose - Many patients with transient ischemic attack (TIA) or minor stroke present to medical attention after a delay of several days or weeks, at which time it may be more difficult to obtain a clear...Background and Purpose - Many patients with transient ischemic attack (TIA) or minor stroke present to medical attention after a delay of several days or weeks, at which time it may be more difficult to obtain a clear history and clinical signs may have resolved. Because ischemic lesions on diffusion- weighted MRI (DWI) often persist for several weeks, we hypothesized that adding DWI to a standard protocol with T2- weighted imaging might be useful in the management of patients presenting late. Methods - We studied consecutive patients with TIA or minor stroke presenting ≥ 3 days after the event. Two independent observers recorded the presence or absence of recent ischemic lesions on 2 different occasions, first with the T2 scan only, and second with T2 and DWI. Each time, with the aid of a written clinical summary, the observers recorded their diagnosis and proposed management. Results - 300 patients (159 men) were scanned at a median of 17 (interquartile range=10 to 23) days after symptom onset. DWI showed a high signal lesion in 114/164 (70% ) minor strokes versus 17/136 (13% ) TIAs (P < 0.0001). The presence of high- signal lesions on DWI decreased nonlinearly with time since symptom onset (F < 0.0001) and increased with National Institutes of Health Stroke Score (P=0.038) and with age (P=0- 01). In 90/206 (43.7% ) patients with 1 or multiple lesions on T2, DWI helped to clarify whether these were related to a recent ischemic event (79 [48% Abstract: strokes; 11 [31% Abstract:- TIAs). Compared with T2 alone, DWI provided additional information in 108 (36% ) patients (91 [56% Abstract: strokes and 17 [13% Abstract: TIAs), such as clarification of clinical diagnosis (18 patients, 6% ) or vascular territory (28 patients, 93% ), which was considered likely to influence management in 42 (14% )- patients (32 [19% Abstract: strokes; 10 [7.4% Abstract: TIAs). Conclusions - The clinically useful information available from DWI provides a further justification for an MRI- based imaging protocol in patients with subacute TIA or minor stroke.展开更多
基金supported by the National Natural Science Foundation of China,Nos.82071307(to HL),82271362(to HL),82171294(to JW),82371303(to JW),and 82301460(to PX)the Natural Science Foundation of Jiangsu Province,No.BK20211552(to HL)+1 种基金Suzhou Medical Technology Innovation Project-Clinical Frontier,No.SKY2022002(to ZY)the Science and Education Foundation for Health of Suzhou for Youth,No.KJXW2023001(to XL)。
文摘Differentiation of oligodendrocyte progenitor cells into mature myelin-forming oligodendrocytes contributes to remyelination.Failure of remyelination due to oligodendrocyte progenitor cell death can result in severe nerve damage.Ferroptosis is an iron-dependent form of regulated cell death caused by membrane rupture induced by lipid peroxidation,and plays an important role in the pathological process of ischemic stroke.However,there are few studies on oligodendrocyte progenitor cell ferroptosis.We analyzed transcriptome sequencing data from GEO databases and identified a role of ferroptosis in oligodendrocyte progenitor cell death and myelin injury after cerebral ischemia.Bioinformatics analysis suggested that perilipin-2(PLIN2)was involved in oligodendrocyte progenitor cell ferroptosis.PLIN2 is a lipid storage protein and a marker of hypoxia-sensitive lipid droplet accumulation.For further investigation,we established a mouse model of cerebral ischemia/reperfusion.We found significant myelin damage after cerebral ischemia,as well as oligodendrocyte progenitor cell death and increased lipid peroxidation levels around the infarct area.The ferroptosis inhibitor,ferrostatin-1,rescued oligodendrocyte progenitor cell death and subsequent myelin injury.We also found increased PLIN2 levels in the peri-infarct area that co-localized with oligodendrocyte progenitor cells.Plin2 knockdown rescued demyelination and improved neurological deficits.Our findings suggest that targeting PLIN2 to regulate oligodendrocyte progenitor cell ferroptosis may be a potential therapeutic strategy for rescuing myelin damage after cerebral ischemia.
基金National Natural Science Foundation of China,No.82001460the Natural Science Foundation of Zhejiang Province,No.LQ21H250001 (both to LS)。
文摘Accumulating evidence has demonstrated the involvement of B cells in neuroinflammation and neuroregeneration.However,the role of B cells in ischemic stroke remains unclear.In this study,we identified a novel phenotype of macrophage-like B cells in brain-infiltrating immune cells expressing a high level of CD45.Macrophage-like B cells chara cterized by co-expression of B-cell and macrophage markers,showed stronger phagocytic and chemotactic functions compared with other B cells and showed upregulated expression of phagocytosis-related genes.Gene Ontology analysis found that the expression of genes associated with phagocytosis,including phagosome-and lysosome-related genes,was upregulated in macrophage-like B cells.The phagocytic activity of macrophage-like B cells was ve rified by immunostaining and three-dimensional reconstruction,in which TREM2-labeled macrophage-like B cells enwrapped and internalized myelin debris after cerebral ischemia.Cell-cell interaction analysis revealed that macrophage-like B cells released multiple chemokines to recruit peripheral immune cells mainly via CCL pathways.Single-cell RNA sequencing showed that the transdiffe rentiation to macrophage-like B cells may be induced by specific upregulation of the transcription factor CEBP fa mily to the myeloid lineage and/or by downregulation of the transcription factor Pax5 to the lymphoid lineage.Furthermore,this distinct B cell phenotype was detected in brain tissues from mice or patients with traumatic brain injury,Alzheimer’s disease,and glioblastoma.Overall,these results provide a new perspective on the phagocytic capability and chemotactic function of B cells in the ischemic brain.These cells may serve as an immunotherapeutic target for regulating the immune response of ischemic stroke.
基金supported by the National Natural Science Foundation of China(81230026 and 81171085)the Natural Science Foundation of Jiangsu Province,China(BL2012013)the Science Foundation of the Bureau of Health of Jiangsu Province,China(LJ201101)
文摘The outcome of early intravenous thrombolysis for ischemic stroke in patients with atrial fibrillation（AF）is worse than that without thrombosis. How to increase the efficacy of intravenous thrombolysis for AF-related ischemic stroke remains largely unknown. In this study, we investigated factors that influence the effect of intravenous thrombolysis in these patients. Our results showed that thrombolysis was independently associated with a favorable outcome（P ／ 0.001） and did not influence the mortality of AF-related ischemic stroke, although it increased the risk of hemorrhage within 24 h after treatment. Risk factors for a poor outcome at admission were：heart failure（P = 0.045）; high systolic pressure（P = 0.039）; high blood glucose（P = 0.030）; and a high National Institutes of Health Stroke Scale（NIHSS） score（P ／ 0.001）. Moreover, high systolic pressure at admission（P = 0.007）, high blood glucose（P = 0.027）, and a high NIHSS score（P ／ 0.001） were independent risk factors for mortality at 3 months. Besides thrombolysis, a high NIHSS score（P = 0.006） and warfarin taken within 48 h before stroke onset（P = 0.032） were also independent risk factors for symptomatic hemorrhage within 24 h after treatment. Ischemic stroke patients with AF benefited from intravenous thrombolysis with recombinant tissue plasminogen activator within 4.5 h after stroke.
基金supported by the National Key R&D Program of China(2022YFE0131000)the National Natural Science Foundation of China(82220108012,82271306,and 82071307)+1 种基金The Science and Education for Health Foundation of Suzhou for Youth(KJXW2023001)the Boxi Youth Natural Science Foundation(BXQN2023028).
文摘During the hyperacute phase of intracerebral hemorrhage(ICH),the mass effect and blood components mechanically lead to brain damage and neurotoxicity.Our findings revealed that the mass effect and transferrin precipitate neuronal oxidative stress and iron uptake,culminating in ferroptosis in neurons.M6A(N6-methyladenosine)modification,the most prevalent mRNA modification,plays a critical role in various cell death pathways.The Fto(fat mass and obesity-associated protein)demethylase has been implicated in numerous signaling pathways of neurological diseases by modulating m6A mRNA levels.Regulation of Fto protein levels in neurons effectively mitigated mass effect-induced neuronal ferroptosis.Applying nanopore direct RNA sequencing,we identified voltage-dependent anion channel 3(Vdac3)as a potential target associated with ferroptosis.Fto influenced neuronal ferroptosis by regulating the m6A methylation of Vdac3 mRNA.These findings elucidate the intricate interplay between Fto,Vdac3,m6A methylation,and ferroptosis in neurons during the hyperacute phase post-ICH and suggest novel therapeutic strategies for ICH.
基金supported by the National Natural Science Foundation of China(Grant Nos.:82071287,81870916)the National Natural Science Foundation of China(Grant No.:81971097)+3 种基金the Basic Public Interests Research Plan of Zhejiang Province,China(Grant No.:GF18H090006)the National Natural Science Foundation of China(Grant No.:81701214)the National Natural Science Foundation of China(Grant No.:82001299)the Natural Science Foundation of Zhejiang Province,China(Grant No.:TGD23C040017).
文摘The role of glial scar after intracerebral hemorrhage(ICH)remains unclear.This study aimed to investigate whether microglia-astrocyte interaction affects glial scar formation and explore the specific function of glial scar.We used a pharmacologic approach to induce microglial depletion during different ICH stages and examine how ablating microglia affects astrocytic scar formation.Spatial transcriptomics(ST)analysis was performed to explore the potential ligand-receptor pair in the modulation of microglia-astrocyte interaction and to verify the functional changes of astrocytic scars at different periods.During the early stage,sustained microglial depletion induced disorganized astrocytic scar,enhanced neutrophil infiltration,and impaired tissue repair.ST analysis indicated that microglia-derived insulin like growth factor 1(IGF1)modulated astrocytic scar formation via mechanistic target of rapamycin(mTOR)signaling activation.Moreover,repopulating microglia(RM)more strongly activated mTOR signaling,facilitating a more protective scar formation.The combination of IGF1 and osteopontin(OPN)was necessary and sufficient for RM function,rather than IGF1 or OPN alone.At the chronic stage of ICH,the overall net effect of astrocytic scar changed from protective to destructive and delayed microglial depletion could partly reverse this.The vital insight gleaned from our data is that sustained microglial depletion may not be a reasonable treatment strategy for early-stage ICH.Inversely,early-stage IGF1/OPN treatment combined with late-stage PLX3397 treatment is a promising therapeutic strategy.This prompts us to consider the complex temporal dynamics and overall net effect of microglia and astrocytes,and develop elaborate treatment strategies at precise time points after ICH.
文摘Background and Purpose -Although white matter is a potential target of acute stroke therapy, there is uncertainty about its relative resistance to ischemia and whether it is capable of mounting a penumbral response. To explore these issues further, we examined the differential effects of ischemia on gray and white matter using magnetic resonance (MR) perfusion-diffusion mismatch after acute stroke. Methods -MR imaging studies were performed within 12 hours in patients with initial hemispheric ischemic stroke. “At-risk”tissue was defined as tissue with abnormal diffusion-weighted imaging/perfusion-weight imaging or infarcti on on follow-up image. Tissue was segmented using a probabilistic atlas generat ed from age-matched controls. The proportions of “at-risk”tissue, which was penumbral at the time of imaging, were compared between gray and white matter. R esults -Thirty-two patients had diffusion-perfusion mismatched penumbral tiss ue present in both gray and white matter compartments. Although the absolute mis match volumes were greater in gray (median 42 cm3, interquartile range 18 to 70 cm3)than in white matter (39 cm3, 17 to 49 cm3;P < 0.001), the proportion of “a t-risk”tissue, which was penumbral at the time of imaging (median 3.7 hours, r ange 1.5 to 9.9 hours) was greater in white (69%, 49%to 86%) than gray matter (62%, 52%to 75%; P=0.026). However, the proportions spontaneously salvaged b y 3 months were similar in both compartments. Conclusions -These findings are c onsistent with white matter being able to mount an ischemic penumbral response i n humans and being more resistant to cerebral ischemia than gray matter. They al so raise the possibility that the therapeutic window is longer for white matter and may require alternative therapeutic strategies.
文摘A contributing factor to the failure of trials of neuroprotectants in acute ischemic stroke may be the differing vulnerability to ischemia of white compared with gray matter. To address this issue, we determined to establish the existence of potentially viable tissue in white matter and its evolution to infarction or salvage in both gray and white matter compartments in patients with ischemic stroke. Twenty- seven patients (mean age, 73.4 years) at a median of 16.5 hours after symptom onset were studied using the hypoxic marker 18F- misonidazole with positron emission tomography (PET). Tissue was segmented using an magnetic resonance probabilistic map. Although there was a greater volume of initially “ at- risk tissue” in gray matter (58.3cm3, 29.9- 93.0cm3) than white matter (42.0cm 3, 15.8- 74.0cm3;p < 0.001) at the time of PET imaging, a higher proportion of this was still potentially viable in white matter (41.4% , 4.6- 74.5% ) than in gray matter (23.6% , 3.2- 61.1% ; p < 0.05). However, a similar proportion in each compartment spontaneously survived. These data provide evidence for the existence of potentially salvageable tissue in human white matter and is consistent with it having a similar or even greater resistance to ischemia than gray matter. For the latter possibility, alternative therapeutic strategies may be required for its salvage.
文摘Clinicians often have to make treatment decisions based on the likelihood that an individual patient will benefit. In this article we consider the relevance of relative and absolute risk reductions, and draw attention to the importance of expressing the results of trials and subgroup analyses in terms of absolute risk. We describe the limitations of univariate subgroup analysis in situations in which there are several determinants of treatment effect, and review the potential for targeting treatments with risk models, especially when benefit is probably going to be dependent on the absolute risk of adverse outcomes with or without treatment. The ability to systematically take into account the characteristics of an individual patient and their interactions, to consider the risks and benefits of interventions separately if needed, and to provide patients with person alised estimates of their likelihood of benefit is shown using the example of endarterectomy for symptomatic carotid stenosis.
文摘Background and Purpose - Many patients with transient ischemic attack (TIA) or minor stroke present to medical attention after a delay of several days or weeks, at which time it may be more difficult to obtain a clear history and clinical signs may have resolved. Because ischemic lesions on diffusion- weighted MRI (DWI) often persist for several weeks, we hypothesized that adding DWI to a standard protocol with T2- weighted imaging might be useful in the management of patients presenting late. Methods - We studied consecutive patients with TIA or minor stroke presenting ≥ 3 days after the event. Two independent observers recorded the presence or absence of recent ischemic lesions on 2 different occasions, first with the T2 scan only, and second with T2 and DWI. Each time, with the aid of a written clinical summary, the observers recorded their diagnosis and proposed management. Results - 300 patients (159 men) were scanned at a median of 17 (interquartile range=10 to 23) days after symptom onset. DWI showed a high signal lesion in 114/164 (70% ) minor strokes versus 17/136 (13% ) TIAs (P < 0.0001). The presence of high- signal lesions on DWI decreased nonlinearly with time since symptom onset (F < 0.0001) and increased with National Institutes of Health Stroke Score (P=0.038) and with age (P=0- 01). In 90/206 (43.7% ) patients with 1 or multiple lesions on T2, DWI helped to clarify whether these were related to a recent ischemic event (79 [48% Abstract: strokes; 11 [31% Abstract:- TIAs). Compared with T2 alone, DWI provided additional information in 108 (36% ) patients (91 [56% Abstract: strokes and 17 [13% Abstract: TIAs), such as clarification of clinical diagnosis (18 patients, 6% ) or vascular territory (28 patients, 93% ), which was considered likely to influence management in 42 (14% )- patients (32 [19% Abstract: strokes; 10 [7.4% Abstract: TIAs). Conclusions - The clinically useful information available from DWI provides a further justification for an MRI- based imaging protocol in patients with subacute TIA or minor stroke.
