Alzheimer's disease (AD) is distressingly common and age is the major risk factor. One of the cha... more Alzheimer's disease (AD) is distressingly common and age is the major risk factor. One of the challenges in AD research is the scarcity of information on the healthy aging brain, since many of features considered part of 'AD pathology' inflammation and oxidant stress-are also present in cognitively normal elderly populations. For this reason it is critical to study AD (and pre-AD) subjects in the context of age-matched controls, an essential feature of the data set which inspired this review. Our study of lipids in cerebrospinal fluid (CSF) of aged subjects is a novel data set, especially as lipids are relatively understudied in AD, with much of the experimental and clinical research literature focused on A-beta and tau. Inflammation too is often discussed as a consequence of rather than active participant in AD pathology. For these reasons we focus on the interplay between inflammation and lipids in the pathological process of AD, an interaction that is likely important in pathophysiology of AD. We present a summary of the complex CSF lipid changes found in our clinical AD studies, and focus in on a few of these changes to highlight the importance of lipid interactions with the brain immune system in the pathogenesis of AD, recognizing that our interpretation of these data requires further study. Neither the full complexity of the brain immune system nor the changes in lipids in CSF can be reviewed here, but we hope that the many interactions highlighted between lipids and the immune system will prompt others to investigate these pathophysiologic connections, leading to a greater understanding of the causes of AD.
Rates of Preeclampsia and Post-preeclamptic Cardiovascular Disease Among US Military Servicewomen: A Retrospective Case-cohort Study, 2023
Preeclampsia (PE), a hypertensive-inflammatory disorder of pregnancy, poses acute risks of seizur... more Preeclampsia (PE), a hypertensive-inflammatory disorder of pregnancy, poses acute risks of seizures, stroke, and heart attack during pregnancy and up to 6 weeks post-delivery. Recent data suggest that residual increased risks for cardiovascular disease (CVD) linger for much longer, possibly decades, after PE pregnancies. In civilian studies, PE and the major vascular events resulting from it disproportionately affect women from minority groups, especially African American women. The Military Health System (MHS) provides equal access to care for all active-duty servicewomen (ADSW), thus theoretically mitigating disparities. Racial/ethnic breakdown for PE and post PE CVD has not been studied in the MHS. Materials and Methods: We identified healthy pregnancies in the MHS electronic health records of ADSW in the years 2009/2010 and those with a PE diagnosis. Patients with preexisting conditions of PE or CVD based on a look-back period of two calendar years were excluded. Cases were matched to controls based on age at pregnancy within 5 years and race/ethnicity. Cohort was assessed for diagnosed CVDs, race, age, and service during 2011-2017. Time to first CVD event was assessed with Cox proportional hazards model, results reported as relative risks (95% CI). All variables were summarized using mean (SD) for normally distributed continuous variables; non-normal continuous variables were characterized by median [IQR] and categorical variables were summarized by counts and frequencies. All statistical testings were two-sided with a significance level of 5% and were completed using SAS-EG version 9.2 or R version 3.5.2. Results: From an analysis of 106,808 inpatient ADSW records, PE incidence by race is 11.8% for White, 12% for African American, 11.4% for Asian/Pacific Islander, 11.2% for Native American, 9.5% for Other, and 7.6% for unknown (not documented) race. Thus, in the US Military, African American women have comparable (0.2% higher) PE rate than White women in contrast with civilian studies that often report much higher incidence in the African American population. Using Asians as referent group, PE increases the risk of CVD. White women have a hazard ratio (HR)
<p>Fresh peripheral blood and UPI samples from healthy 3<sup>rd</sup> trimester... more <p>Fresh peripheral blood and UPI samples from healthy 3<sup>rd</sup> trimester pregnant women and preeclamptic women were processed and analyzed as described in Materials and Methods. Gated starting with Fig 1B lymphocyte gate and subjected to Fig 1A Steps 2–5. (A, B) CD4+ (left side) or CD8+ (right side), CCR7+ or–, CD45RA+ (A) or CD45RO+ (B) sub-populations were identified as previously described[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188250#pone.0188250.ref007" target="_blank">7</a>]. (C, E) Intracellular cytokine staining of naïve (C) and memory (E) CD4+ and CD8+ T cells. PB (circles) or UPI lymphocytes (squares) were cultured for 4.5h as described in Materials and Methods including PMA/Ionomycin and Golgi Plug treatment. (E) Number of IL-2+ CD4 T cells as determined in C) (both left and right) per CD8+ T cell in the same patient in the PB (circles) and UPI (squares) of healthy (solid) or preeclamptic (open) patients. Student’s T test, unpaired *<i>P</i><0.05, **<i>P</i><0.009, ***<i>P</i><0.0005.</p
In a prior study, we used flow cytometry to characterize lymphocytes from mother-infant pairs fro... more In a prior study, we used flow cytometry to characterize lymphocytes from mother-infant pairs from healthy and preeclamptic pregnancies. Despite a relatively low number of study participants, we acquired a large, multidimensional dataset and felt limited in our capacity to fully explore it. Here we describe the use of Mathematica to create an interactive display tool that allows dynamic data exploration. The end result is a HIPAA compliant data library and code that can be exported, published, and explored by readers with the freely available MathReader application. Our database included flow cytometry data from 8 staining panels with up to 15 markers each, clinical, and obstetric data in MS Excel. By combining Mathematica’s Chart, Manipulate, and Tooltip functions, we incorporated the clinical variables including neonatal sex, birth weight, and prior obstetric history into each graph, while the Tooltip function displays the participant study ID. We have coded an interactive tool th...
The risk factors for preeclampsia, extremes of maternal age, changing paternity, concomitant mate... more The risk factors for preeclampsia, extremes of maternal age, changing paternity, concomitant maternal autoimmunity, and/or birth intervals greater than 5 years, suggest an underlying immunopathology. We used peripheral blood and lymphocytes from the UteroPlacental Interface (UPI) of 3rd trimester healthy pregnant women in multicolor flow cytometry-and in vitro suppression assays. The major end-point was the characterization of activation markers, and potential effector functions of different CD4-and CD8 subsets as well as T regulatory cells (Treg). We observed a significant shift of peripheral CD4 -and CD8- T cells from naïve to memory phenotype in preeclamptic women compared to healthy pregnant women consistent with long-standing immune activation. While the proportions of the highly suppressive Cytokine and Activated Treg were increased in preeclampsia, Treg tolerance toward fetal antigens was dysfunctional. Thus, our observations indicate a long-standing inflammatory derangement ...
Maternal-fetal chimerism is miniscule, a testament to the integrity of the uteroplacental interfa... more Maternal-fetal chimerism is miniscule, a testament to the integrity of the uteroplacental interface. The soundness of this border region is potentially altered through cesarean delivery of prior babies with uncertain consequences for the following pregnancies. Using multicolor flow cytometry and quantitative PCR of non-inherited maternal antigens we performed a retrospective case control pilot study and formulated the null hypothesis that placental implantation over a prior uterine scar does not result in the presence of memory Treg (CD45RO+) in the fetus. We then performed a power calculation and performed a blinded, appropriately powered prospective case control study to test the null hypothesis. Fetuses born to mothers with prior uterine scar have a roughly five times higher maternal to fetal microchimerism when the placenta directly interacts with the uterine scar. Unlike exposure to antigens in adult life, in utero antigenic exposure induces tolerogenic (Treg) responses in fetu...
Clinical organ transplantation became possible only after powerful immunosuppressive drugs became... more Clinical organ transplantation became possible only after powerful immunosuppressive drugs became available to suppress the alloimmune response. After decades of solid organ transplantation, organ rejection is still a major challenge. However, significant insight into allorecognition has emerged from this vast experience and should be used to inform future stem cell-based therapies. For this reason, we review the current understanding of selected topics in transplant immunology that have not been prominent in the stem cell literature, including immune responses to ischemia/reperfusion injuries, natural killer cells, the adaptive immune response, some unresolved issues in T-cell allorecognition, costimulatory molecules, and the anticipated role of regulatory T cells in graft tolerance.
In utero hematopoietic stem cell transplantation (IUHCT) is an attractive approach and a potentia... more In utero hematopoietic stem cell transplantation (IUHCT) is an attractive approach and a potentially curative surgery for several congenital hematopoietic diseases. In practice, this application has succeeded only in the context of Severe Combined Immunodeficiency Disorders. Here, we review potential immunological hurdles for the long-term establishment of chimerism and discuss relevant models and findings from both postnatal hematopoietic stem cell transplantation and IUHCT.
Preeclampsia affects 3-17% of pregnancies worldwide and has serious consequences for both the mot... more Preeclampsia affects 3-17% of pregnancies worldwide and has serious consequences for both the mother and the fetus. As maternal-fetal immune tolerance is bidirectional, fetal immunopathology may play a significant role in the pathogenesis of pregnancy disorders. Nevertheless, the impact of preeclampsia on the fetal immune system is unclear. In this case-control study, we examined the phenotype of innate and adaptive immune cells from the cord blood of 3rd trimester babies born to healthy mothers and compared them to cord blood from 3rd trimester babies born to mothers with symptomatic preeclampsia. The ratio of CD56hi CD16- non-activated/regulatory NK cells to CD56lo CD16+ activated/effector NK cells as well as the proportion of CD4+ T cells was significantly decreased in the cord blood of babies born to preeclamptic mothers. The percentage of FoxP3+ Treg, especially the FoxP3lo populations (resting Treg and cytokine Treg), were significantly reduced. Importantly, this reduction in FoxP3+ Treg affected the ratio of CD8+ effector T cells per FoxP3+ Treg in the cord blood of babies born to preeclamptic mothers. These observations indicate that there are significant fetal immune system derangements during preeclampsia.
Alzheimer's disease (AD) is distressingly common and age is the major risk factor. One of the cha... more Alzheimer's disease (AD) is distressingly common and age is the major risk factor. One of the challenges in AD research is the scarcity of information on the healthy aging brain, since many of features considered part of 'AD pathology' inflammation and oxidant stress-are also present in cognitively normal elderly populations. For this reason it is critical to study AD (and pre-AD) subjects in the context of age-matched controls, an essential feature of the data set which inspired this review. Our study of lipids in cerebrospinal fluid (CSF) of aged subjects is a novel data set, especially as lipids are relatively understudied in AD, with much of the experimental and clinical research literature focused on A-beta and tau. Inflammation too is often discussed as a consequence of rather than active participant in AD pathology. For these reasons we focus on the interplay between inflammation and lipids in the pathological process of AD, an interaction that is likely important in pathophysiology of AD. We present a summary of the complex CSF lipid changes found in our clinical AD studies, and focus in on a few of these changes to highlight the importance of lipid interactions with the brain immune system in the pathogenesis of AD, recognizing that our interpretation of these data requires further study. Neither the full complexity of the brain immune system nor the changes in lipids in CSF can be reviewed here, but we hope that the many interactions highlighted between lipids and the immune system will prompt others to investigate these pathophysiologic connections, leading to a greater understanding of the causes of AD.
Rates of Preeclampsia and Post-preeclamptic Cardiovascular Disease Among US Military Servicewomen: A Retrospective Case-cohort Study, 2023
Preeclampsia (PE), a hypertensive-inflammatory disorder of pregnancy, poses acute risks of seizur... more Preeclampsia (PE), a hypertensive-inflammatory disorder of pregnancy, poses acute risks of seizures, stroke, and heart attack during pregnancy and up to 6 weeks post-delivery. Recent data suggest that residual increased risks for cardiovascular disease (CVD) linger for much longer, possibly decades, after PE pregnancies. In civilian studies, PE and the major vascular events resulting from it disproportionately affect women from minority groups, especially African American women. The Military Health System (MHS) provides equal access to care for all active-duty servicewomen (ADSW), thus theoretically mitigating disparities. Racial/ethnic breakdown for PE and post PE CVD has not been studied in the MHS. Materials and Methods: We identified healthy pregnancies in the MHS electronic health records of ADSW in the years 2009/2010 and those with a PE diagnosis. Patients with preexisting conditions of PE or CVD based on a look-back period of two calendar years were excluded. Cases were matched to controls based on age at pregnancy within 5 years and race/ethnicity. Cohort was assessed for diagnosed CVDs, race, age, and service during 2011-2017. Time to first CVD event was assessed with Cox proportional hazards model, results reported as relative risks (95% CI). All variables were summarized using mean (SD) for normally distributed continuous variables; non-normal continuous variables were characterized by median [IQR] and categorical variables were summarized by counts and frequencies. All statistical testings were two-sided with a significance level of 5% and were completed using SAS-EG version 9.2 or R version 3.5.2. Results: From an analysis of 106,808 inpatient ADSW records, PE incidence by race is 11.8% for White, 12% for African American, 11.4% for Asian/Pacific Islander, 11.2% for Native American, 9.5% for Other, and 7.6% for unknown (not documented) race. Thus, in the US Military, African American women have comparable (0.2% higher) PE rate than White women in contrast with civilian studies that often report much higher incidence in the African American population. Using Asians as referent group, PE increases the risk of CVD. White women have a hazard ratio (HR)
<p>Fresh peripheral blood and UPI samples from healthy 3<sup>rd</sup> trimester... more <p>Fresh peripheral blood and UPI samples from healthy 3<sup>rd</sup> trimester pregnant women and preeclamptic women were processed and analyzed as described in Materials and Methods. Gated starting with Fig 1B lymphocyte gate and subjected to Fig 1A Steps 2–5. (A, B) CD4+ (left side) or CD8+ (right side), CCR7+ or–, CD45RA+ (A) or CD45RO+ (B) sub-populations were identified as previously described[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188250#pone.0188250.ref007" target="_blank">7</a>]. (C, E) Intracellular cytokine staining of naïve (C) and memory (E) CD4+ and CD8+ T cells. PB (circles) or UPI lymphocytes (squares) were cultured for 4.5h as described in Materials and Methods including PMA/Ionomycin and Golgi Plug treatment. (E) Number of IL-2+ CD4 T cells as determined in C) (both left and right) per CD8+ T cell in the same patient in the PB (circles) and UPI (squares) of healthy (solid) or preeclamptic (open) patients. Student’s T test, unpaired *<i>P</i><0.05, **<i>P</i><0.009, ***<i>P</i><0.0005.</p
In a prior study, we used flow cytometry to characterize lymphocytes from mother-infant pairs fro... more In a prior study, we used flow cytometry to characterize lymphocytes from mother-infant pairs from healthy and preeclamptic pregnancies. Despite a relatively low number of study participants, we acquired a large, multidimensional dataset and felt limited in our capacity to fully explore it. Here we describe the use of Mathematica to create an interactive display tool that allows dynamic data exploration. The end result is a HIPAA compliant data library and code that can be exported, published, and explored by readers with the freely available MathReader application. Our database included flow cytometry data from 8 staining panels with up to 15 markers each, clinical, and obstetric data in MS Excel. By combining Mathematica’s Chart, Manipulate, and Tooltip functions, we incorporated the clinical variables including neonatal sex, birth weight, and prior obstetric history into each graph, while the Tooltip function displays the participant study ID. We have coded an interactive tool th...
The risk factors for preeclampsia, extremes of maternal age, changing paternity, concomitant mate... more The risk factors for preeclampsia, extremes of maternal age, changing paternity, concomitant maternal autoimmunity, and/or birth intervals greater than 5 years, suggest an underlying immunopathology. We used peripheral blood and lymphocytes from the UteroPlacental Interface (UPI) of 3rd trimester healthy pregnant women in multicolor flow cytometry-and in vitro suppression assays. The major end-point was the characterization of activation markers, and potential effector functions of different CD4-and CD8 subsets as well as T regulatory cells (Treg). We observed a significant shift of peripheral CD4 -and CD8- T cells from naïve to memory phenotype in preeclamptic women compared to healthy pregnant women consistent with long-standing immune activation. While the proportions of the highly suppressive Cytokine and Activated Treg were increased in preeclampsia, Treg tolerance toward fetal antigens was dysfunctional. Thus, our observations indicate a long-standing inflammatory derangement ...
Maternal-fetal chimerism is miniscule, a testament to the integrity of the uteroplacental interfa... more Maternal-fetal chimerism is miniscule, a testament to the integrity of the uteroplacental interface. The soundness of this border region is potentially altered through cesarean delivery of prior babies with uncertain consequences for the following pregnancies. Using multicolor flow cytometry and quantitative PCR of non-inherited maternal antigens we performed a retrospective case control pilot study and formulated the null hypothesis that placental implantation over a prior uterine scar does not result in the presence of memory Treg (CD45RO+) in the fetus. We then performed a power calculation and performed a blinded, appropriately powered prospective case control study to test the null hypothesis. Fetuses born to mothers with prior uterine scar have a roughly five times higher maternal to fetal microchimerism when the placenta directly interacts with the uterine scar. Unlike exposure to antigens in adult life, in utero antigenic exposure induces tolerogenic (Treg) responses in fetu...
Clinical organ transplantation became possible only after powerful immunosuppressive drugs became... more Clinical organ transplantation became possible only after powerful immunosuppressive drugs became available to suppress the alloimmune response. After decades of solid organ transplantation, organ rejection is still a major challenge. However, significant insight into allorecognition has emerged from this vast experience and should be used to inform future stem cell-based therapies. For this reason, we review the current understanding of selected topics in transplant immunology that have not been prominent in the stem cell literature, including immune responses to ischemia/reperfusion injuries, natural killer cells, the adaptive immune response, some unresolved issues in T-cell allorecognition, costimulatory molecules, and the anticipated role of regulatory T cells in graft tolerance.
In utero hematopoietic stem cell transplantation (IUHCT) is an attractive approach and a potentia... more In utero hematopoietic stem cell transplantation (IUHCT) is an attractive approach and a potentially curative surgery for several congenital hematopoietic diseases. In practice, this application has succeeded only in the context of Severe Combined Immunodeficiency Disorders. Here, we review potential immunological hurdles for the long-term establishment of chimerism and discuss relevant models and findings from both postnatal hematopoietic stem cell transplantation and IUHCT.
Preeclampsia affects 3-17% of pregnancies worldwide and has serious consequences for both the mot... more Preeclampsia affects 3-17% of pregnancies worldwide and has serious consequences for both the mother and the fetus. As maternal-fetal immune tolerance is bidirectional, fetal immunopathology may play a significant role in the pathogenesis of pregnancy disorders. Nevertheless, the impact of preeclampsia on the fetal immune system is unclear. In this case-control study, we examined the phenotype of innate and adaptive immune cells from the cord blood of 3rd trimester babies born to healthy mothers and compared them to cord blood from 3rd trimester babies born to mothers with symptomatic preeclampsia. The ratio of CD56hi CD16- non-activated/regulatory NK cells to CD56lo CD16+ activated/effector NK cells as well as the proportion of CD4+ T cells was significantly decreased in the cord blood of babies born to preeclamptic mothers. The percentage of FoxP3+ Treg, especially the FoxP3lo populations (resting Treg and cytokine Treg), were significantly reduced. Importantly, this reduction in FoxP3+ Treg affected the ratio of CD8+ effector T cells per FoxP3+ Treg in the cord blood of babies born to preeclamptic mothers. These observations indicate that there are significant fetal immune system derangements during preeclampsia.
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Papers by Andrea Loewendorf PhD