Трансплантация пластов мезенхимальных прогениторных клеток сердца для васкуляризации миокарда после инфаркта

Purpose. To develop a method of producing tissue-engineered constructs (TECs) on the basis of resident mesenchymal progenitor cells (MPC) of the human heart and to assess the effect of TECs transplantation on regenerative processes in the heart using a model of myocardial infarction in rats.Materials and methods. Human resident MPCs were isolated from the right atrial auricle of CAD patients. A similar protocol was used to obtain MPCs from Wistar rats. The MPC immunophenotype was determined by cytofluorometry. Corresponding TECs were obtained on the basis of MPC sheets of human and rats' hearts. Myocardial infarction in rats was induced by ligation of the anterior descending coronary artery followed by TEC transplantation. Euthanasia was performed 30 days after the transplantation. Histological examination of the implant and vascularization cells, morphometric analysis, tracking of the MPC differentiation ability, determination of the content of growth factors by solid-phase ELISA were carried out. Statistical evaluation of the significance of differences was performed using the Statistica 8.0 software package.Results. The analysis of the obtained cell constructs showed that they consisted of several layers of cells interacting with each other by means of connexin 43 and were characterized by good cell viability as a part TECs. The number of vessels in the peri-infarction area under the transplant from the MPC was significantly higher than that in the reference group with signs of differentiation of cardiac MPCs transplanted into endothelial vascular cells.The increased vascularization was combined with an increase in the area of viable myocardial sites and a decrease in LV cavity dilation. Analysis of the cardiac MPC secretion products showed that they produce the most important growth factors and cytokines that regulate angiogenesis and migration of stem cells.Conclusion. The strategy of using epicardial TEC transplantation based on MPC sheets seems to be a rational approach for effective delivery of viable stem/progenitor cells to the damaged myocardium. The use of TEC helps to reduce or temporarily eliminate the effect of factors that contribute to progressive heart dysfunction by local paracrine exposure and activation of the revascularization processes in the affected zone.Цель. Разработать способ получения тканеинженерных конструкций (ТИК), на основе резидентных мезенхимальных прогениторных клеток (МПК) сердца человека и оценить влияние трансплантации ТИК на регенеративные процессы в сердце на модели инфаркта миокарда крысы.Материалы и методы. Резидентные МПК человека выделяли из ушка правого предсердия пациентов с ИБС. По аналогичному протоколу выделяли МПК крысы линии Wistar. Методом проточной цитофлуориметрии определяли иммунофенотип МПК. На основе пластов МПК сердца человека и крыс получали соответствующие ТИК. Инфаркт миокарда у крыс был индуцирован путем перевязки передней нисходящей коронарной артерии, после чего проводили трансплантацию ТИК. Через 30 дней после трансплантации выполняли эвтаназию. Проводили гистологическую оценку состояния клеток имплантата и васкуляризации, морфометрический анализ, трекинг дифференцировочной способности МПК, определение содержания ростовых факторов методом твердофазного ИФА. Статистическую оценку достоверности различий проводили с использованием программного пакета Statistica 8.0.Результаты. Анализ полученных клеточных конструкций показал, что они состоят из нескольких слоев клеток, взаимодействующих между собой при помощи коннексин–43, и характеризуются хорошей жизнеспособностью клеток в составе ТИК. Количество сосудов в периинфарктной области под трансплантатом из МПК было значительно больше, чем в контрольной группе, с признаками дифференцировки трансплантированных МПК сердца в эндотелиальные клетки сосудов.Увеличение васкуляризации сочеталось с увеличением площади участков жизнеспособного миокарда, уменьшением дилатации полости ЛЖ. Анализ продуктов секреции МПК сердца показал, что они продуцируют важнейшие факторы роста и цитокины, регулирующие ангиогенез и миграцию стволовых клеток.Заключение. Стратегия использования эпикардиальной трансплантации ТИК на основе пластов из МПК представляется рациональным подходом для эффективной доставки жизнеспособных стволовых/прогениторных клеток в поврежденный миокард. Применение ТИК способствует уменьшению или временному исключению действия факторов, способствующих прогрессирующей дисфункции сердца, путем локального паракринного воздействия и активации процессов реваскуляризации зоны повреждения

Активность аутофагии в клетках эпикарда при развитии острого перикардита

Pericarditis is a group of polyetiological diseases often associated with emergence of life– threatening conditions. Poor knowledge of underlying cellular mechanisms and lack of relevant approaches to investigation of pericarditis result in major challenges in diagnosis and treatment.The aim of this work was to identify changes in the activity of autophagy in epicardial cells in acute pericarditis.Materials and methods. Acute pericarditis in mice was induced by intrapericardial injection of Freund's adjuvant in the study group (n=15). The control group included animals receiving either intrapericardial injection of phosphate-buffered saline (PBS) (n=15), or sham surgery without injections (n=7). On Days 3 or 5 after surgery the animals were euthanized under isoflurane anesthesia. Immunofluorescence staining of cardiac tissue cryo-sections and immunoblotting were used to assess the intensity of inflammation and autophagy in the epicardium.Results. Inflammation and other signs of acute pericarditis resulting in thickening of some epicardial areas were found: 68+9% in the control (after PBS injection) and 124+22% after Freund's adjuvant injection (p=0.009); other signs included cellular infiltration of epicardium and multiple adhesions. The epicardial layer exhibited signs of mesothelial cells reorganization with 11-fold increase of autophagy markers LC3 II/LC3 I ratio: 0.07+0.02 in the control group (after PBS injection) and 0.84+0.07 - in acute pericarditis (p=0.04), and accumulation of collagen fibers.Conclusion. Development of acute pericarditis is accompanied by activation of epicardial mesothelial cells, intensified autophagy and development of fibrous changes in epicacardial/ subepicardial areas.Перикардит – это группа полиэтилогичных заболеваний, которые часто ассоциированы с развитием жизнеугрожающих состояний. Существенные сложности при их диагностике и лечении в значительной степени обусловлены ограниченным пониманием клеточных механизмов развития перикардита и отсутствием релевантных подходов при его изучении.Цель данной работы: выявление изменения активности аутофагии в клетках эпикарда при остром перикардите.Материалы и методы. Острый перикардит в сердце мышей моделировали путем интраперикардиального введения 50 мкл адъюванта Фрейнда (n=15). Контрольным животным интраперкардиально вводили 50 мкл раствора фосфатно-солевого буфера (ФСБ) (n=15) или выполняли операции без интраперикардиального введения какого-либо препарата (ложнооперированные животные, n=7). На 3-й или 5-й день от проведения хирургической операции после ингаляционной наркотизации изофлюраном производили эвтаназию животных. Активность воспаления в зоне эпикарда и выраженность аутофагии исследовали с помощью иммунофлуоресцентных методов окрашивания криосрезов сердца и иммуноблотинга.Результаты. Обнаружили развитие воспалительной реакции и появление признаков острого перикардита, ассоциированного с утолщением зоны эпикарда: 68+9% в контроле (после введения ФСБ) и 124+22% после введения адъюванта Фрейнда, p=0,009, его полиморфно-клеточной инфильтрацией и формированием множественных спаек. В составе эпикардиального слоя наблюдали признаки реорганизации клеток мезотелия, 11-кратное повышение соотношения в них маркеров аутофагии LC3 II/LC3 I: 0,07+0,02 в контроле (после введения ФСБ) и 0,84+0,07 при остром перикардите, р=0,04, а также аккумуляцию коллагеновых волокон.Заключение. Развитие острого перикардита сопровождается активацией клеток эпикардиального мезотелия, повышением выраженности аутофагии и развитием фиброзных изменений в зоне эпикарда/субэпикарда. Изучение возможности модуляции аутофагии с целью воздействия на развитие острого перикардита является предметом дальнейших исследований

Native diversity buffers against severity of non-native tree invasions

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species$^{1,2}$. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies$^{3,4}$. Here, leveraging global tree databases$^{5,6,7}$, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions

The global biogeography of tree leaf form and habit

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling

The global biogeography of tree leaf form and habit.

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling

Native diversity buffers against severity of non-native tree invasions

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions

Native diversity buffers against severity of non-native tree invasions.

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions

The global biogeography of tree leaf form and habit

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17–34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling

The global biogeography of tree leaf form and habit

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cyclin