Biomedical subjects

Michal A Elovitz

Publications and source records attributed to Michal A Elovitz.

10 recordsLinked to original sources

PubMed2026

A scalable, low-cost, sample hashing workflow for multiomic single-cell analysis using the Seq-Well S3 platform.

In-depth analyses of clinical samples have the potential to provide unparalleled insights into the cellular mechanisms that underlie both health and disease, as well as therapeutic and prophylactic responses. However, these specimens are often paucicellular, necessitating the use of workflows that maximize the amount of information that can be learned. Here we provide a detailed protocol for generating and analyzing single-cell multiomic data from low-input samples with the Seq-Well S3 platform. We further describe a matched pipeline for sample hashing that reduces costs and sources of technical variation in the resulting data while also enhancing throughput. In brief, our streamlined and efficient methodology involves: (1) optionally staining single-cell suspensions with antibody-oligonucleotide conjugates for cell surface protein quantification and/or sample multiplexing; (2) generating Seq-Well S3 sequencing libraries; (3) optionally producing bulk-RNA sequencing libraries via SMART-seq2 to support genetic demultiplexing; and (4) computationally analyzing the resulting data. Each step herein has been designed to leverage readily available reagents and standard laboratory equipment, substantially lowering barriers to entry for researchers. The overall Protocol can yield high-quality multiomic insights from samples in under a week.

Single-Cell Analysis↗

PubMed2006

Anti-inflammatory interventions in pregnancy: now and the future.

A growing body of evidence implicates inflammatory pathways in adverse reproductive outcomes. This expanding evidence suggests that anti-inflammatory interventions may hold promise in reducing the maternal and neonatal morbidities and mortalities associated with these obstetrical complications. Preterm birth, preeclampsia, pregnancy loss and adverse neonatal outcomes have all been associated with the activation of inflammatory pathways during pregnancy. Because of the number of observational human studies, as well as animal models of preterm birth, the mechanisms by which inflammation may promote preterm parturition and adverse effects on the fetus are beginning to be elucidated. Although the future use of anti-inflammatory interventions in this context holds significant promise, much research is still warranted. Only when the pathogenesis of obstetrical complications is more fully understood can meaningful therapeutic interventions become a realistic goal.

Anti-Inflammatory Agents↗

PubMed2006

Placental inflammation and viral infection are implicated in second trimester pregnancy loss.

OBJECTIVE: Second trimester pregnancy loss continues to be a poorly understood adverse obstetric outcome. A case control study was performed to determine if: (1) similar to early spontaneous preterm birth, second trimester loss is associated with histologic chorioamnionitis (HCA); and (2) if HCA is present, which organisms may mediate this placental inflammation. STUDY DESIGN: Cases were patients with a spontaneous second trimester loss. Controls were patients who presented for induction of labor for fetal or maternal indications. Nested polymerase chain reaction (PCR) was performed on placental tissues to detect the presence of viruses and pathogenic and atypical bacteria. Chi-square and Fisher exact test were used to determine if HCA and/or the presence of virus or bacteria were significantly associated with second trimester loss. The associations of interest were adjusted for possible confounders using multivariable logistic regression. RESULTS: HCA was more prevalent in cases (67%) than controls (16%) (P < .001). Seventy-nine percent (66/84) of cases and 44% (7/16) of controls were positive for any virus (P = .01). The rate of bacterial infection was similar in both cases and controls (P = .35). In multivariable logistic regression models, HCA (odds ratio [OR] 14.58, 2.62-81.15) and the presence of any virus (OR 6.62, 1.56-28.07) were independently associated with second trimester loss. CONCLUSION: These studies demonstrate that spontaneous second trimester loss is strongly associated with HCA and viral infections.

Abortion, Spontaneous↗

PubMed2006

The use of progestational agents for preterm birth: lessons from a mouse model.

OBJECTIVE: On the basis of the recent Maternal Fetal Medicine Unit Networks clinical trial, the American College of Obstetricians and Gynecologists supports the administration of 17-alpha hydroxyprogesterone caproate to high-risk patients. Because inflammation/infection is believed to be a contributing factor in many cases of preterm birth, it is imperative to understand the effect of 17-alpha hydroxyprogesterone caproate treatment in this clinical situation. STUDY DESIGN: Using a mouse model of localized intrauterine inflammation, we investigated the ability of progestational agents to prevent preterm birth. On gestational day 15 (E15), dams were assigned randomly to treatment with 17-alpha hydroxyprogesterone caproate, medroxyprogesterone acetate, or vehicle before intrauterine infusion of lipopolysaccharide. All dams were monitored for morbidity and preterm birth. Three separate sets of experiments were performed to assess different outcomes at 6, 24, and 96 hours. At 6 and 24 hours, C-reactive protein, interleukin-6, and interleukin-10 levels were measured in maternal serum by enzyme-linked immunosorbent assay. RESULTS: Pretreatment with 17-alpha hydroxyprogesterone caproate or medroxyprogesterone acetate before intrauterine lipopolysaccharide treatment significantly decreased the preterm birth rate, compared with lipopolysaccharide treatment alone. Medroxyprogesterone acetate treatment was more effective than 17-alpha hydroxyprogesterone caproate treatment in the prevention of preterm birth and resulted in live pups at term. Treatment with 17-alpha hydroxyprogesterone caproate was associated with significant maternal morbidity. CONCLUSION: In the setting of intrauterine inflammation, progestational agents decrease the preterm birth rate but can result in maternal morbidity. 17-Alpha hydroxyprogesterone caproate should not be used in patients who are suspected of having subclinical infection and/or acute preterm labor. The mechanisms by which progestational agents inhibit preterm birth warrants further investigations so that the use of this drug to appropriate populations could be pursued without undue fetal or maternal harm.

17 alpha-Hydroxyprogesterone Caproate↗

PubMed2006

Nausea, emesis, and muscle weakness in a pregnant adolescent.

BACKGROUND: Gitelman syndrome is a rare autosomal recessive disorder that presents in early adulthood with fatigue, muscle cramps and electrolyte abnormalities. CASE: A 17-year-old African-American woman presented at 17 weeks of pregnancy with nausea, emesis, profound lower extremity proximal muscle weakness, hypokalemia, and hypomagnesemia. After a thorough evaluation, Gitelman syndrome was diagnosed. The patient was maintained on high levels of potassium and magnesium supplementation throughout the rest of her pregnancy and delivered a healthy infant. CONCLUSION: In pregnancy, nausea and emesis is most commonly attributed to hyperemesis gravidarum. However, an atypical presentation of these symptoms and/or the coexistence of less common complaints warrant further investigation.

Adolescent↗

PubMed2006

Transcytosis of Human immunodeficiency virus 1 across the placenta is enhanced by treatment with tumour necrosis factor alpha.

The human placenta is relatively resistant to Human immunodeficiency virus 1 (HIV-1), but obstetric complications associated with inflammatory processes, including chorioamnionitis and spontaneous preterm delivery, are associated with increased rates of vertical transmission. It was hypothesized that the pro-inflammatory mediator tumour necrosis factor alpha (TNF-alpha), which promotes HIV-1 transmission across endothelial membranes, increases HIV-1 transmission across the placenta. Flow cytometry and immunostaining studies were performed, which demonstrated that the HIV-1 receptors CD4, CCR5 and CXCR4 were not expressed by villous trophoblast cells. Consequently, primary villous trophoblast cells were not infected with cell-free HIV-1 isolates, as measured by in situ PCR and quantitative PCR, but villous trophoblast cells were infected by HIV-1-infected peripheral blood mononuclear cells (PBMC). HIV-1 from infected PBMC was rapidly transported across confluent transformed trophoblast cell monolayers by transcytosis, and TNF-alpha significantly upregulated transcytosis of HIV-1 across the trophoblast layer without disrupting cell viability or confluency. Inhibitors of TNF-alpha (antibodies against TNF-alpha and TNF-alpha receptors) and an anti-inflammatory drug (tenidap) significantly reduced transcytosis rates. It was concluded that the villous trophoblast is resistant to infection by cell-free HIV-1 but susceptible to transcytosis of HIV-1 from infected PBMC, and inflammatory mediators such as TNF-alpha may play a critical role in promoting maternal-fetal transmission of HIV-1.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2005

Elucidating the early signal transduction pathways leading to fetal brain injury in preterm birth.

Adverse neurologic outcome, including cerebral palsy, is a significant contributor to long-term morbidity in preterm neonates. However, the mechanisms leading to brain injury in the setting of a preterm birth are poorly understood. In the last decade, there has been a growing body of evidence correlating infection or inflammation with preterm birth. The presence of intrauterine inflammation significantly increases the risk for adverse neurologic outcome in the neonate. These studies were performed to elucidate the early signal transduction pathways activated in the fetal brain that may result in long-term neurologic injury. Using our mouse model of localized intrauterine inflammation, the activation of TH1/TH2 pathways in the placenta, fetus corpus, fetal liver, and fetal brain was investigated. Additional studies determined whether activation of TH1/TH2 pathways could promote cell death and alter glial development. Real-time PCR studies demonstrated that a robust TH1/TH2 response occurs rapidly in the fetal brain after exposure to intrauterine inflammation. The cytokine response in the fetus and placenta was not significantly correlated with the response in the fetal brain. Along with an immune response, cell death pathways were activated early in the fetal brain in response to intrauterine LPS. Implicating TH1/TH2 and cell death pathways in permanent brain injury are our findings of an increase in GFAP mRNA and protein as well as a loss of pro-oligodendrocytes. With increased understanding of the mechanisms by which inflammation promotes brain injury in the preterm neonate, identification of potential targets to limit adverse neonatal outcomes becomes possible.

Animals↗

PubMed2005

Can medroxyprogesterone acetate alter Toll-like receptor expression in a mouse model of intrauterine inflammation?

OBJECTIVE: Activation of the innate immune receptors, Toll-like receptors 2 and 4, are critical for a host inflammatory response to both Gram-positive and Gram-negative organisms. These receptors can initiate and modulate the inflammatory response. Differential regulation of Toll-like receptors may be one of the mechanisms by which intrauterine inflammation signals parturition. Likewise, progestational agents may have the ability to modify this effect. These studies were performed to elucidate the effect of intrauterine inflammation and medroxyprogesterone acetate on Toll-like receptor expression in the uterus, cervix, and placenta in a mouse model of intrauterine inflammation. STUDY DESIGN: On day 15 of gestation, CD-1 mice were randomized to pretreatment with medroxyprogesterone acetate or vehicle before intrauterine infusion with lipopolysaccharide or sterile saline solution. Six hours after intrauterine infusion, uterine, cervical, and placental tissues were harvested. RNA and protein were extracted. Quantitative polymerase chain reaction was performed for Toll-like receptor 2 and 4 messenger RNA. Western blot analysis was performed with Toll-like receptor 4-specific antibodies. RESULTS: Intrauterine inflammation up-regulated Toll-like receptor 2 and 4 messenger RNA in uterus, cervix, and placenta. Pretreatment with medroxyprogesterone acetate decreased the lipopolysaccharide-induced up-regulation of Toll-like receptor 2 and 4 messenger RNA in the cervix and placenta. Medroxyprogesterone acetate treatment, in the presence of lipopolysaccharide, was unable to prevent the lipopolysaccharide-induced increase in Toll-like receptor 4 messenger RNA and protein in the uterus. Medroxyprogesterone acetate treatment alone in pregnant mice significantly increased Toll-like receptor 4 messenger RNA expression in the uterus. CONCLUSION: Intrauterine inflammation has a differential effect on Toll-like receptor 2 and 4 expression. The observed up-regulation of Toll-like receptor 2 in the uterus in response to intrauterine lipopolysaccharide may be a mechanism to augment the inflammatory response and may serve to promote parturition in the setting of inflammation. Consequently, the ability of medroxyprogesterone acetate to suppress lipopolysaccharide-induced up-regulation of Toll-like receptor 2 messenger RNA may be one of the mechanisms by which progestins are able to decrease preterm birth.

Animals↗

PubMed2004

Animal models of preterm birth.

Preterm birth continues to pose a significant clinical dilemma and contributes to both acute and long-term neonatal morbidity. Despite efforts, the incidence of preterm birth has not decreased, partly because of our lack of understanding of the mechanisms that trigger parturition. Animal models are essential research tools for investigating the pathways that promote preterm parturition and for testing therapeutic interventions. Growing evidence correlates infection or inflammation with preterm birth. Consequently, many investigators have created animal models that reflect these findings. Current models of preterm parturition include diverse species, varying means of inducing an inflammatory or infectious state, and different routes of administration. Although each of these models can advance our knowledge, it is important to understand their advantages, disadvantages and unique characteristics. An understanding of such models will hopefully promote continued research that will ultimately lead to a decrease in preterm birth and an improvement in neonatal outcome.

Amnion↗

PubMed2003

A new model for inflammation-induced preterm birth: the role of platelet-activating factor and Toll-like receptor-4.

Preterm birth is a leading cause of neonatal morbidity and mortality. Despite a growing body of evidence correlating inflammation with preterm birth, the signal transduction pathways responsible for the emptying of the uterus in the setting of intrauterine inflammation has not been elucidated. We now report a unique, reproducible mouse model of localized intrauterine inflammation. This model results in 100% preterm delivery with no maternal mortality. Using our model, we also show that platelet-activating factor is a crucial mediator of both inflammation-induced preterm birth and fetal demise. Using C3H/HeJ mice, we demonstrate that toll-like receptor-4 (TLR-4) plays a role in lipopolysaccharide-induced preterm birth but not in inflammation-induced fetal death. Immunohistochemistry studies demonstrate the presence of the platelet-activating factor receptor in both endometrial glands and smooth muscle in uterine tissues. Molecular studies demonstrate the differential expression of platelet-activating factor receptor and TLR-4 in uterine and cervical tissue throughout gestation. Quantitative polymerase chain reaction revealed an up-regulation of TLR-4 in the fundal region of the uterus in response to intrauterine inflammation. The use of this model will increase our understanding of the significant clinical problem of inflammation-induced preterm birth and will elucidate signal transduction pathways involved in an inflammatory state.

Animals↗