Strengths and limitations of diagnostic tools for endometriosis and relevance in diagnostic test accuracy research

Endometriosis is a chronic systemic disease that can cause pain, infertility and reduced quality of life. Diagnosing endometriosis remains challenging, which yields diagnostic delays for patients. Research on diagnostic test accuracy in endometriosis can be difficult due to verification bias, as not all patients with endometriosis undergo definitive diagnostic testing. The purpose of this State-of-the-Art Review is to provide a comprehensive update on the strengths and limitations of the diagnostic modalities used in endometriosis and discuss the relevance of diagnostic test accuracy research pertaining to each. We performed a comprehensive literature review of the following methods: clinical assessment including history and physical examination, biomarkers, diagnostic imaging, surgical diagnosis and histopathology. Our review suggests that, although non-invasive diagnostic methods, such as clinical assessment, ultrasound and magnetic resonance imaging, do not yet qualify formally as replacement tests for surgery in diagnosing all subtypes of endometriosis, they are likely to be appropriate for advanced stages of endometriosis. We also demonstrate in our review that all methods have strengths and limitations, leading to our conclusion that there should not be a single gold-standard diagnostic method for endometriosis, but rather, multiple accepted diagnostic methods appropriate for different circumstances. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

The female reproductive tract microbiotas, inflammation, and gynecological conditions

The intricate interactions between the host cells, bacteria, and immune components that reside in the female reproductive tract (FRT) are essential in maintaining reproductive tract homeostasis. Much of our current knowledge surrounding the FRT microbiota relates to the vaginal microbiota, where ‘health’ has long been associated with low bacterial diversity and Lactobacillus dominance. This concept has recently been challenged as women can have a diverse vaginal microbial composition in the absence of symptomatic disease. The structures of the upper FRT (the endocervix, uterus, Fallopian tubes, and ovaries) have distinct, lower biomass microbiotas than the vagina; however, the existence of permanent microbiotas at these sites is disputed. During homeostasis, a balance exists between the FRT bacteria and the immune system that maintains immune quiescence. Alterations in the bacteria, immune system, or local environment may result in perturbances to the FRT microbiota, defined as dysbiosis. The inflammatory signature of a perturbed or “dysbiotic” FRT microbiota is characterized by elevated concentrations of pro-inflammatory cytokines in cervical and vaginal fluid. It appears that vaginal homeostasis can be disrupted by two different mechanisms: first, a shift toward increased bacterial diversity can trigger vaginal inflammation, and second, local immunity is altered in some manner, which disrupts the microbiota in response to an environmental change. FRT dysbiosis can have negative effects on reproductive health. This review will examine the increasing evidence for the involvement of the FRT microbiotas and inflammation in gynecologic conditions such as endometriosis, infertility, and endometrial and ovarian cancer; however, the precise mechanisms by which bacteria are involved in these conditions remains speculative at present. While only in their infancy, the use of antibiotics and probiotics to therapeutically alter the FRT microbiota is being studied and is discussed herein. Our current understanding of the intimate relationship between immunity and the FRT microbiota is in its early days, and more research is needed to deepen our mechanistic understanding of this relationship and to assess how our present knowledge can be harnessed to assist in diagnosis and treatment of gynecologic conditions.

Endometrial microbiota is more diverse in people with endometriosis than symptomatic controls

Endometriosis is a chronic, estrogen-dependent gynecological condition affecting approximately 10% of reproductive age women. The most widely accepted theory of its etiology includes retrograde menstruation. Recent reports suggest the uterus is not sterile. Thus, the refluxed menstrual effluent may carry bacteria, and contribute to inflammation, the establishment and growth of endometriotic lesions. Here, we compared and contrasted uterine bacteria (endometrial microbiota) in people with surgically confirmed presence (N = 12) or absence of endometriosis (N = 9) using next-generation 16S rRNA gene sequencing. We obtained an average of > 9000 sequence reads per endometrial biopsy, and found the endometrial microbiota of people with endometriosis was more diverse (greater Shannon Diversity Index and proportion of 'Other' taxa) than symptomatic controls (with pelvic pain, surgically confirmed absence of endometriosis; diagnosed with other benign gynecological conditions). The relative abundance of bacterial taxa enriched in the endometrial microbiota of people with endometriosis belonged to the Actinobacteria phylum (Gram-positive), Oxalobacteraceae (Gram-negative) and Streptococcaceae (Gram-positive) families, and Tepidimonas (Gram-negative) genus, while those enriched in the symptomatic controls belonged to the Burkholderiaceae (Gram-negative) family, and Ralstonia (Gram-negative) genus. Taken together, results suggest the endometrial microbiota is perturbed in people with endometriosis.

Quality appraisal of systematic reviews on methods of labour induction: a systematic review

PURPOSE

Induction of labour has become more common over the last decade, together with an increase in the number of systematic reviews of the subject. However, with multiple systematic reviews it is necessary to evaluate the methodological rigor to ensure the reliability of conclusions and recommendations for clinical practice. Therefore, the aim of this study was to appraise the quality of systematic reviews that examined the efficacy and/or safety of labour induction methods.

METHODS

An electronic search of MEDLINE, Embase, and the Cochrane Library from 2000 to 2020 was conducted. Study selection, data extraction and quality assessment were conducted using A Measurement Tool to Assess Systematic Reviews (AMSTAR) by two independent reviewers, in duplicate.

RESULTS

The search identified 387 publications, of which 48 studies (13%) met the a priori inclusion criteria. No significant relationships were found between study quality and number of citations, journal impact factor, or publication year.

CONCLUSION

Methodological quality for systematic reviews on the induction of labour were ranked as moderate with no significant changes in quality over the past 2 decades. Publication characteristics are not significantly associated with methodological quality, indicating that healthcare professionals should critically appraise studies before applying them to practice.

Advances in Humanized Mouse Models to Improve Understanding of HIV-1 Pathogenesis and Immune Responses

Although antiretroviral therapy has transformed human immunodeficiency virus-type 1 (HIV-1) from a deadly infection into a chronic disease, it does not clear the viral reservoir, leaving HIV-1 as an uncurable infection. Currently, 1.2 million new HIV-1 infections occur globally each year, with little decrease over many years. Therefore, additional research is required to advance the current state of HIV management, find potential therapeutic strategies, and further understand the mechanisms of HIV pathogenesis and prevention strategies. Non-human primates (NHP) have been used extensively in HIV research and have provided critical advances within the field, but there are several issues that limit their use. Humanized mouse (Hu-mouse) models, or immunodeficient mice engrafted with human immune cells and/or tissues, provide a cost-effective and practical approach to create models for HIV research. Hu-mice closely parallel multiple aspects of human HIV infection and disease progression. Here, we highlight how innovations in Hu-mouse models have advanced HIV-1 research in the past decade. We discuss the effect of different background strains of mice, of modifications on the reconstitution of the immune cells, and the pros and cons of different human cells and/or tissue engraftment methods, on the ability to examine HIV-1 infection and immune response. Finally, we consider the newest advances in the Hu-mouse models and their potential to advance research in emerging areas of mucosal infections, understand the role of microbiota and the complex issues in HIV-TB co-infection. These innovations in Hu-mouse models hold the potential to significantly enhance mechanistic research to develop novel strategies for HIV prevention and therapeutics.

Differential Elevation of Inflammation and CD4+ T Cell Activation in Kenyan Female Sex Workers and Non-Sex Workers Using Depot-Medroxyprogesterone Acetate

Background

Depot Medroxyprogesterone (DMPA) is one of the most widely used contraceptives in Sub-Saharan Africa where HIV incidence is high. We explored the effect of DMPA on the activation of HIV cellular targets and inflammation as a possible mechanism of increased HIV risk with DMPA use. Since sex work is known to affect the immune system, this study aimed to understand the effect of DMPA on the immune system among sex workers and non-sex worker women.

Methods

Twenty-seven DMPA-using HIV seronegative female sex workers (FSW) and 30 DMPA-using HIV seronegative non-sex worker (SW) women were enrolled in the study. Twenty-four FSWs and 30 non-sex workers who were not using any hormonal contraception (no HC) were recruited as controls. Blood and cervico-vaginal samples were collected from all participants and assayed for T cell activation and proinflammatory cytokines.

Results

Among no HC users, sex workers had lower expression of CD38 and CD69 on blood-derived CD4⁺ T cells along with lower CD4⁺CCR5⁺ cells frequency in the endocervix. Plasma MCP-1, TNFα and IL-17 also had reduced expression in FSW not using HC. Non-sex workers using DMPA had elevated proportions of blood-derived CD4⁺CD38⁺, CD4⁺CD69⁺ and CD4⁺HLA-DR⁺ T cells relative to non-sex workers who were not taking any HC. DMPA-using non-sex workers also had an increased level of plasma interferon gamma (IFN-γ), monokine induced by interferon-γ (MIG) and sCD40L, alongside higher proportion of CD4⁺CD38⁺ and CD4⁺CD69⁺ T cells at the cervix compared to non-sex workers no-HC controls., Finally, non-sex workers and FSWs using DMPA had similar levels of genital and peripheral CD4⁺ T cell activation and inflammation.

Conclusion

DMPA increased inflammation and expression of activation markers on potential HIV target cells in non-sex workers. These data show that DMPA is a strong immune modulator and its use counteracts the decreased immune activation associated with sex work. These findings suggest that inflammation and increased HIV target cells in blood and at the genital tract may be mechanisms by which DMPA increases susceptibility to HIV.

Depot medroxyprogesterone acetate (DMPA) enhances susceptibility and increases the window of vulnerability to HIV-1 in humanized mice

The progestin-based hormonal contraceptive Depot Medroxyprogesterone Acetate (DMPA) is widely used in sub-Saharan Africa, where HIV-1 is endemic. Meta-analyses have shown that women using DMPA are 40% more likely than women not using hormonal contraceptives to acquire Human Immunodeficiency Virus (HIV-1). Therefore understanding how DMPA increases susceptibility to HIV-1 is an important public health issue. Using C57BL/6 mice and our previously optimized humanized mouse model (NOD-Rag1^tm1Mom Il2rg^tm1Wjl transplanted with hCD34-enriched hematopoietic stem cells; Hu-mice) where peripheral blood and tissues are reconstituted by human immune cells, we assessed how DMPA affected mucosal barrier function, HIV-1 susceptibility, viral titres, and target cells compared to mice in the diestrus phase of the estrous cycle, when endogenous progesterone is highest. We found that DMPA enhanced FITC-dextran dye leakage from the vaginal tract into the systemic circulation, enhanced target cells (hCD68+ macrophages, hCD4+ T cells) in the vaginal tract and peripheral blood (hCD45+hCD3+hCD4+hCCR5+ T cells), increased the rate of intravaginal HIV-1 infection, extended the window of vulnerability, and lowered vaginal viral titres following infection. These findings suggest DMPA may enhance susceptibility to HIV-1 in Hu-mice by impairing the vaginal epithelial barrier, increasing vaginal target cells (including macrophages), and extending the period of time during which Hu-mice are susceptible to infection; mechanisms that might also affect HIV-1 susceptibility in women.

Brain-derived neurotrophic factor (BDNF) expression and function in the mammalian reproductive Tract

BACKGROUND

Neurotrophins of the nerve growth factor family are soluble polypeptides that are best known for their role in nerve growth, survival and differentiation in the central nervous system. A growing body of literature shows that neurotrophins and their receptors are also expressed throughout the reproductive tract.

OBJECTIVE AND RATIONALE

Neurotrophins are key regulatory proteins in reproductive physiology during development and throughout adult life. Of the neurotrophins, the literature describing the expression and function of brain-derived neurotrophic factor (BDNF) and its high-affinity receptor, neurotrophin receptor kinase-2 (NTRK2), has been expanding rapidly. We therefore conducted a systematic inductive qualitative review of the literature to better define the role of the BDNF in the reproductive tract. We postulate that BDNF and NTRK2 are central regulatory proteins throughout the reproductive system.

SEARCH METHODS

An electronic search of Medline (PubMed) and Web of Science for articles relating to BDNF and the reproductive system was carried out between January 2018 and February 2019.

OUTCOMES

In the ovary, BDNF expression and levels have been linked with follicle organisation during ovarian development, follicle recruitment and growth and oocyte maturation. In the endometrium, BDNF is involved in cell proliferation and neurogenesis. In contrast, literature describing the role of BDNF in other reproductive tissues is sparse and BDNF-NTRK2 signalling in the male reproductive tract has been largely overlooked. Whilst estradiol appears to be the primary regulator of BDNF expression, we also identified reports describing binding sites for glucocorticoid and myocyte enhancer factor-2, a calcium-response element through activation of an N-methyl-D-aspartate (NMDA) receptor, and aryl hydrocarbon receptor nuclear transporter protein-4 (ARNT) response elements in promoter regions of the BDNF gene. Expression is also regulated by multiple microRNAs and post-translational processing of precursor proteins and intracellular shuttling. BDNF-NTRK2 signalling is modulated through tissue specific receptor expression of either the full-length or truncated NTRK2 receptor; however, the functional importance remains to be elucidated. Dysregulation of BDNF expression and circulating concentrations have been implicated in several reproductive disorders including premature ovarian failure, endometriosis, pre-eclampsia, intra-uterine growth restriction (IUGR) and several reproductive cancers.

WIDER IMPLICATIONS

We conclude that BDNF and its receptors are key regulatory proteins central to gonadal development, ovarian regulation and uterine physiology, as well as embryo and placenta development. Furthermore, dysregulation of BDNF-NTRK2 in reproductive diseases suggests their potential role as candidate clinical markers of disease and potential therapeutic targets.

Factors affecting stability of plasma brain-derived neurotrophic factor

Circulating concentrations of brain-derived neurotrophic factor (BDNF) have been linked to cancer, neuropsychiatric, diabetes, and gynecological disorders. However, factors influencing plasma storage and subsequent BDNF quantification are incompletely understood. Therefore, the anticoagulant used in plasma separator tubes, storage-time, storage-temperature, and repeated freeze–thaw cycles on circulating BDNF concentrations was evaluated. Peripheral blood samples were collected from healthy women (n = 14) and men (n = 10) recruited prospectively from McMaster University (August 2014). Blood was collected from the cubital vein into plasma separator tubes containing five different anticoagulant systems [K2EDTA, Li-Hep, Li-Hep (gel), Na-Hep, Na-Hep (glass)], and placed on ice for transport to the lab for centrifugation. Plasma samples (n = 16) collected in K2EDTA tubes from women recruited to a previous study (April 2011 to December 2012) were used to determine the effect of multiple freeze–thaw cycles. Plasma BDNF was quantified using a commercially available ELISA kit. Plasma concentrations of BDNF were significantly affected by the type of plasma separator tube, storage-time, and number of freeze–thaw cycles. Storage temperature (− 20 vs. − 80 °C) did not significantly affect the quantity of BDNF measured as mean BDNF concentrations generally fell within our calculated acceptable change limit up to 6 months in the freezer. Our results suggest that for quantification of circulating BDNF blood collected in K2EDTA tubes and plasma stored up to 6 months at either − 20 or − 80 °C produces reproducible results that fall within an acceptable range. However, plasma samples stored beyond 6 months and repeated freeze–thaw cycles should be avoided.

Curcumin Can Decrease Tissue Inflammation and the Severity of HSV-2 Infection in the Female Reproductive Mucosa

Herpes Simplex Virus Type 2 (HSV-2) is one of the most prevalent sexually transmitted viruses and is a known risk factor for HIV acquisition in the Female Genital Tract (FGT). Previously, we found that curcumin can block HSV-2 infection and abrogate the production of inflammatory cytokines and chemokines by genital epithelial cells in vitro. In this study, we investigated whether curcumin, encapsulated in nanoparticles and delivered by various in vivo routes, could minimize inflammation and prevent or reduce HSV-2 infection in the FGT. Female mice were pre-treated with curcumin nanoparticles through oral, intraperitoneal and intravaginal routes, and then exposed intravaginally to the tissue inflammation stimulant CpG-oligodeoxynucleotide (ODN). Local intravaginal delivery of curcumin nanoparticles, but not intraperitoneal or oral delivery, reduced CpG-mediated inflammatory histopathology and decreased production of pro-inflammatory cytokines Interleukin (IL)-6, Tumor Necrosis Factor Alpha (TNF-α) and Monocyte Chemoattractant Protein-1 (MCP-1) in the FGT. However, curcumin nanoparticles did not demonstrate anti-viral activity nor reduce tissue pathology when administered prior to intravaginal HSV-2 infection. In an alternative approach, intravaginal pre-treatment with crude curcumin or solid dispersion formulations of curcumin demonstrated increased survival and delayed pathology following HSV-2 infection. Our results suggest that curcumin nanoparticle delivery in the vaginal tract could reduce local tissue inflammation. The anti-inflammatory properties of curcumin delivered to the vaginal tract could potentially reduce the severity of HSV-2 infection and decrease the risk of HIV acquisition in the FGT of women.

Medroxyprogesterone acetate alters the vaginal microbiota and microenvironment in women and increases susceptibility to HIV-1 in humanized mice

The hormonal contraceptive medroxyprogesterone acetate (MPA) is associated with increased risk of human immunodeficiency virus (HIV), via incompletely understood mechanisms. Increased diversity in the vaginal microbiota modulates genital inflammation and is associated with increased HIV-1 acquisition. However, the effect of MPA on diversity of the vaginal microbiota is relatively unknown. In a cohort of female Kenyan sex workers, negative for sexually transmitted infections (STIs), with Nugent scores <7 (N=58 of 370 screened), MPA correlated with significantly increased diversity of the vaginal microbiota as assessed by 16S rRNA gene sequencing. MPA was also significantly associated with decreased levels of estrogen in the plasma, and low vaginal glycogen and α-amylase, factors implicated in vaginal colonization by lactobacilli, bacteria that are believed to protect against STIs. In a humanized mouse model, MPA treatment was associated with low serum estrogen, low glycogen and enhanced HIV-1 susceptibility. The mechanism by which the MPA-mediated changes in the vaginal microbiota may contribute to HIV-1 susceptibility in humans appears to be independent of inflammatory cytokines and/or activated T cells. Altogether, these results suggest MPA-induced hypo-estrogenism may alter key metabolic components that are necessary for vaginal colonization by certain bacterial species including lactobacilli, and allow for greater bacterial diversity in the vaginal microbiota.

This article has an associated First Person interview with the first author of the paper.

Summary: MPA may increase susceptibility to HIV-1 in sex workers through the suppression of endogenous estrogen, reducing vaginal glycogen and α-amylase levels, which increases bacterial diversity, potentially reducing protective bacterial species such as lactobacilli.

The relationship between sex hormones, the vaginal microbiome and immunity in HIV-1 susceptibility in women

The role of sex hormones in regulating immune responses in the female genital tract has been recognized for decades. More recently, it has become increasingly clear that sex hormones regulate susceptibility to sexually transmitted infections through direct and indirect mechanisms involving inflammation and immune responses. The reproductive cycle can influence simian/human immunodeficiency virus (SHIV) infections in primates and HIV-1 infection in ex vivo cervical tissues from women. Exogenous hormones, such as those found in hormonal contraceptives, have come under intense scrutiny because of the increased susceptibility to sexually transmitted infections seen in women using medroxyprogesterone acetate, a synthetic progestin-based contraceptive. Recent meta-analyses concluded that medroxyprogesterone acetate enhanced HIV-1 susceptibility in women by 40%. In contrast, estradiol-containing hormonal contraceptives were not associated with increased susceptibility and some studies reported a protective effect of estrogen on HIV/SIV infection, although the underlying mechanisms remain incompletely understood. Recent studies describe a key role for the vaginal microbiota in determining susceptibility to sexually transmitted infections, including HIV-1. While Lactobacillus spp.-dominated vaginal microbiota is associated with decreased susceptibility, complex microbiota, such as those seen in bacterial vaginosis, correlates with increased susceptibility to HIV-1. Interestingly, sex hormones are inherently linked to microbiota regulation in the vaginal tract. Estrogen has been postulated to play a key role in establishing a Lactobacillus-dominated microenvironment, whereas medroxyprogesterone acetate is linked to hypo-estrogenic effects. The aim of this Review is to contribute to a better understanding of the sex-hormone-microbiome-immunity axis, which can provide key information on the determinants of HIV-1 susceptibility in the female genital tract and, consequently, inform HIV-1 prevention strategies.

Role of sex hormones and the vaginal microbiome in susceptibility and mucosal immunity to HIV-1 in the female genital tract

While the prevalence of Human immunodeficiency virus-1 (HIV-1) infection has stabilized globally, it continues to be the leading cause of death among women of reproductive age. The majority of new infections are transmitted heterosexually, and women have consistently been found to be more susceptible to HIV-1 infection during heterosexual intercourse compared to men. This emphasizes the need for a deeper understanding of how the microenvironment in the female genital tract (FGT) could influence HIV-1 acquisition. This short review focuses on our current understanding of the interplay between estrogen, progesterone, and the cervicovaginal microbiome and their immunomodulatory effects on the FGT. The role of hormonal contraceptives and bacterial vaginosis on tissue inflammation, T cell immunity and HIV-1 susceptibility is discussed. Taken together, this review provides valuable information for the future development of multi-purpose interventions to prevent HIV-1 infection in women.

Altered expression of chemokines and their receptors at porcine maternal-fetal interface during early and mid-gestational fetal loss

Chemokines play a significant role in pregnancy, especially during embryonic attachment and placental development. During early pregnancy, immune cells are recruited extensively to the endometrium in several species including pigs. However, this recruitment is solely mediated by the presence of the conceptus in pigs making it a unique feature compared with other species (humans, primates and mice). To understand the biological significance of chemokine expression and immune cell recruitment in the context of fetal loss, we investigate a well-characterized porcine fetal loss model during the window of early pregnancy at gestational day (gd) 20 and mid-pregnancy (gd50). These periods coincide with 25-40 % of conceptus loss. Using targeted quantitative polymerase chain reaction and Western blot approaches, we screened a specific set of chemokines. Comparisons were made with endometrial lymphocytes (ENDO LY), endometrium and chorioallantoic membranes (CAM) associated with spontaneously arresting and healthy conceptus attachment sites (CAS). mRNA expression studies revealed an increased expression of CXCR3 and CCR5 in ENDO LY and of CXCL10, CXCR3, CCL5 and CCR5 in the endometrium associated with arresting CAS at gd20. DARC was decreased in the endometrium at gd50. CCL1 was increased in CAM associated with arresting CAS at gd50. Some of these differences were also noted at the protein level (CXCL10, CXCR3, CCL5 and CCR5) in the endometrium and CAM. CD45+ immunohistochemistry demonstrated a significantly higher localization in ENDO LY in the endometrium associated with healthy versus arresting counterparts. Most of these differences were observed in early pregnancy and might contribute towards a shift in immune cell functions.

mRNA destabilizing factors: tristetraprolin expression at the porcine maternal-fetal interface

PROBLEM

To evaluate the expression of the tristetraprolin family and their selected targets during porcine pregnancy.

METHOD OF STUDY

Using qPCR and Western blot, mRNA and protein levels were compared between endometrium and chorioallantoic membrane (CAM) associated with healthy and impaired conceptuses at gestation day (gd) 20 and gd50, respectively. Immunohistochemistry was performed to determine localization of TIS11 family members at gd20 and 50.

RESULTS

Multiple significant differences (P < 0.05) in TIS11 family transcripts were observed in the aforementioned comparisons. GM-CSF was significantly higher in healthy endometrium and CAM from impaired conceptus attachment sites. TNF-α was elevated in CAM as compared to endometrium at gd50, regardless of conceptus health status. Immunohistochemical staining shows TIS11 family expressed in the glandular and luminal epithelium, as well as stromal cells in the uterus.

CONCLUSIONS

The shift in the expression of tristetraprolin (TTP) and TIS11D points to a potential role of these genes in regulating spontaneous fetal loss.

Expression of leptin and its long form receptor at the porcine maternal-fetal interface: contrasting healthy and arresting conceptus attachment sites during early and mid-pregnancy

BACKGROUND

It is well established that spontaneous conceptus loss in swine is associated with an imbalance of both angiogenic and immunological factors. Leptin (LEP), a metabolic hormone, has also been implicated in the promotion of angiogenesis. In this study, LEP and its long form receptor (OB-Rb) were evaluated during porcine pregnancy to assess their basal level of expression and their potential role in conceptus development.

METHODS

Expression and secretion of LEP and OB-Rb were quantified in the endometrium of non-pregnant (n = 5), and in the endometrium and chorioallantoic membrane (CAM) of pregnant sows (parity 2 to 5) at gestational days (gd) 20 (n = 8) and 50 (n = 8). Data were analyzed by a 3-way ANOVA testing the effects of conceptus health, tissue type and gestational day.

RESULTS

Leptin and OB-Rb transcripts were significantly higher (P < 0.05) in pregnant than in non-pregnant sows. Significantly greater LEP (P < 0.001) was detected in the endometrial tissue at gd20 compared with gd50. At the protein level, the lowest LEP expression (P < 0.01) was detected in the CAM at gd50, while OB-Rb protein was significantly lower (P < 0.01) at gd50 in the CAM than in the endometrium collected from gd20 and gd50 conceptus attachment sites. Immunofluorescence staining confirmed the expression of these proteins at both gestational days and in both tissue types.

CONCLUSIONS

Changes in the expression patterns of LEP and OB-Rb between gd20 and gd50 suggest a role for the LEP/OB-R complex at the early stages of porcine pregnancy, possibly affecting the attachment process. Further mechanistic studies are warranted to understand the specific role of leptin in porcine pregnancy.

MicroRNAs, immune cells and pregnancy

MicroRNAs (miRNAs) are a recently discovered class of non-coding RNAs that are expressed in many cell types, where they regulate the expression of complementary RNAs, thus modulating the stability and translation of mRNAs. miRNAs are predicted to regulate the expression of ∼50% of all protein coding genes in mammals. Therefore, they participate in virtually all cellular processes investigated so far. Altered miRNAs expressions are associated with both physiological (pregnancy) and pathological processes (cancer). As the dynamic maternal-fetal interface plays a critical role in the maintenance of successful pregnancy, it is not surprising that the miRNAs that are unique to reproductive tissues are abundantly expressed. Research in this field has demonstrated the presence and dysregulation of a distinct set of pregnancy-associated miRNAs; however, most studies have centered on localizing various miRNAs in reproductive microdomains associated with normal or complicated pregnancies. Although several independent miRNA regulatory mechanisms associated with endometrial receptivity, immune cells, angiogenesis and placental development have been studied, miRNA-mediated regulation of pregnancy remains poorly understood. This review provides a summary of the current data on miRNA regulation as well as functional profiles of miRNAs that are found in the uterus, in immune cells associated with maternal tolerance to the fetus, and those involved in angiogenesis and placental development.

The brain-uterus connection: brain derived neurotrophic factor (BDNF) and its receptor (Ntrk2) are conserved in the mammalian uterus

The neurotrophins are neuropeptides that are potent regulators of neurite growth and survival. Although mainly studied in the brain and nervous system, recent reports have shown that neurotrophins are expressed in multiple target tissues and cell types throughout the body. Additionally, dysregulation of neurotrophins has been linked to several disease conditions including Alzheimer's, Parkinson's, Huntington's, psychiatric disorders, and cancer. Brain derived neurotrophic factor (BDNF) is a member of the neurotrophin family that elicits its actions through the neurotrophic tyrosine receptor kinase type 2 (Ntrk2). Together BDNF and Ntrk2 are capable of activating the adhesion, angiogenesis, apoptosis, and proliferation pathways. These pathways are prominently involved in reproductive physiology, yet a cross-species examination of BDNF and Ntrk2 expression in the mammalian uterus is lacking. Herein we demonstrated the conserved nature of BDNF and Ntrk2 across several mammalian species by mRNA and protein sequence alignment, isolated BDNF and Ntrk2 transcripts in the uterus by Real-Time PCR, localized both proteins to the glandular and luminal epithelium, vascular smooth muscle, and myometrium of the uterus, determined that the major isoforms expressed in the human endometrium were pro-BDNF, and truncated Ntrk2, and finally demonstrated antibody specificity. Our findings suggest that BDNF and Ntrk2 are transcribed, translated, and conserved across mammalian species including human, mouse, rat, pig, horse, and the bat.

The microRNAome of pregnancy: deciphering miRNA networks at the maternal-fetal interface

MicroRNAs (miRNAs) post-transcriptionally regulate a vast network of genes by inhibiting mRNA translation. Aberrant miRNA expression profiles have been implicated in pathologies and physiological processes including pregnancy and angiogenesis. Using our established model of implantation failure and spontaneous fetal loss in pigs (Sus scrofa), 236 miRNAs were profiled and compared between 1) non-pregnant and pregnant endometrium, 2) maternal and fetal tissues, and 3) viable and growth-arrested conceptus attachment sites by microarray and Real-Time PCR. Many significant differences in miRNA expression were observed between each of the aforementioned comparisons, and several were validated by PCR. Results indicated which miRNAs were important during pregnancy, which were elevated on the maternal or fetal side of the maternal-fetal interface, and they implicated the maternal expression of miR-10a, 27a, 29c, 323, 331-5p, 339-3p, 374b-5p, and 935 in the spontaneous loss observed in pigs. Several putative mRNA targets of the miRNAs (elevated in endometrium associated with arresting conceptuses) were assessed by quantitative Real-Time PCR and were depressed, supporting their regulation by miRNAs. Finally, targets were clustered by function to obtain ranked lists of gene networks that indicated which pathways/physiological processes might be important in non-pregnant (extracellular matrix factors) versus pregnant endometrium (nuclear transcription factor regulation), maternal (blood vessel development) versus fetal (neuronal differentiation) tissue, and healthy (extracellular matrix factors) versus arresting (GRAM domain) conceptus attachment sites. Overall, we demonstrate the presence of miRNAs on both sides of the maternal-fetal interface, implicate them in spontaneous fetal loss, and present a unique glimpse into the vast microRNAome of pregnancy.

Animal models for anti-angiogenic therapy in endometriosis

Endometriosis is a gynecological disease characterized by the growth of endometrium outside of the uterine cavity. It is often associated with dysmenorrhea, dyspareunia, pelvic pain and infertility. One of the key requirements for endometriotic lesions to survive is development of a blood supply to support their growth. Indeed, dense vascularization is characteristic feature of endometriotic lesions. This has led to the idea that suppression of blood vessel growth (anti-angiogenic therapy) may be a successful therapeutic approach for endometriosis. Potential effectiveness of anti-angiogenic therapies has been assessed in some animal models but there are no reports of human clinical trials. Without understanding the specific mechanism by which endometriosis lesions establish a new blood supply, short-term animal experiments will have limited value for translation into human medicine. Further, it is crucial to use appropriate animal models to assess efficacy of anti-angiogenic compounds. Syngeneic and autologous rodent models, where endometrial fragments are auto-transplanted into the peritoneal cavity are commonly used in anti-angiogenic therapy studies. Another approach is xenograft models where human endometrium is engrafted into immunodeficient mice. Here we review the animal models and experimental techniques used to evaluate anti-angiogenic therapies for endometriosis. We also review our own work on the role of stromal cell derived factor-1 in the recruitment of endothelial progenitor cells in endometriotic lesion angiogenesis, and the effects of the anti-angiogenic peptide ABT-898, a thrombospondin-1 mimetic, on endometriotic lesion growth and vascular development.

An overview of molecular and cellular mechanisms associated with porcine pregnancy success or failure

Prenatal mortality remains one of the major constraints for the commercial pig industry in North America. Twenty to thirty per cent of the conceptuses are lost early in gestation and an additional 10-15% is lost by mid-to-late gestation. Research over the last two decades has provided critical insights into how uterine capacity, placental efficiency, genetics, environment, nutrition and immune mechanisms impact successful conceptus growth; however, the exact cause and effect relationship in the context of foetal loss has yet to be determined. Similar to other mammalian species such as the human, mouse, rat, and primates, immune cell enrichment occurs at the porcine maternal-foetal interface during the window of conceptus attachment. However, unlike other species, immune cells are solely recruited by conceptus-derived signals. As pigs have epitheliochorial placentae where maternal and foetal tissue layers are separate, it provides an ideal model to study immune cell interactions with foetal trophoblasts. Our research is focused on the immune-angiogenesis axis during porcine pregnancy. It is well established that immune cells are recruited to the maternal-foetal interface, but their pregnancy specific functions and how the local milieu affects angiogenesis and inflammation at the site of foetal arrest remain unknown. Through a better understanding of how immune cells modulate crosstalk between the conceptus and the mother, it might be possible to therapeutically target immune cells and/or their products to reduce foetal loss. In this review, we provide evidence from the literature and from our own work into the immunological factors associated with porcine foetal loss.

Selection and validation of reference genes for miRNA expression studies during porcine pregnancy

MicroRNAs comprise a family of small non-coding RNAs that modulate several developmental and physiological processes including pregnancy. Their ubiquitous presence is confirmed in mammals, worms, flies and plants. Although rapid advances have been made in microRNA research, information on stable reference genes for validation of microRNA expression is still lacking. Real time PCR is a widely used tool to quantify gene transcripts. An appropriate reference gene must be chosen to minimize experimental error in this system. A small difference in miRNA levels between experimental samples can be biologically meaningful as these entities can affect multiple targets in a pathway. This study examined the suitability of six commercially available reference genes (RNU1A, RNU5A, RNU6B, SNORD25, SCARNA17, and SNORA73A) in maternal-fetal tissues from healthy and spontaneously arresting/dying conceptuses from sows were separately analyzed at gestation day 20. Comparisons were also made with non-pregnant endometrial tissues from sows. Spontaneous fetal loss is a prime concern to the commercial pork industry. Our laboratory has previously identified deficits in vasculature development at maternal-fetal interface as one of the major participating causes of fetal loss. Using this well-established model, we have extended our studies to identify suitable microRNA reference genes. A methodical approach to assessing suitability was adopted using standard curve and melting curve analysis, PCR product sequencing, real time PCR expression in a panel of gestational tissues, and geNorm and NormFinder analysis. Our quantitative real time PCR analysis confirmed expression of all 6 reference genes in maternal and fetal tissues. All genes were uniformly expressed in tissues from healthy and spontaneously arresting conceptus attachment sites. Comparisons between tissue types (maternal/fetal/non-pregnant) revealed significant differences for RNU5A, RNU6B, SCARNA17, and SNORA73A expression. Based on our methodical assessment of all 6 reference genes, results suggest that RNU1A is the most stable reference gene for porcine pregnancy studies.

Expression of angiogenic basic fibroblast growth factor, platelet derived growth factor, thrombospondin-1 and their receptors at the porcine maternal-fetal interface

BACKGROUND

Commercial swine breeds in North America undergo two waves of spontaneous fetal loss; one during peri-attachment and another during mid-gestation. Although an exact mechanism for this loss is not known, deficits in vasculature at the attachment sites appear to be a major cause. We hypothesized that a balance between pro-angiogenic and anti-angiogenic factors is needed at the maternal-fetal interface for successful conceptus development. Six selected members of the pro-angiogenic fibroblast growth factor (FGF) and platelet derived growth factor (PDGF) families and anti-angiogenic factor thrombospondin-1 (TSP-1) and its receptor CD36 were quantified and localized at the porcine maternal-fetal interface at early and midgestation time points.

METHODS

Mesometrial endometrium was collected from non-pregnant gilts (n = 8). Endometrial and chorioallantoic membrane samples were collected from healthy and arresting conceptus attachment sites at gestation day (gd) 20 (n = 8) and gd 50 (n = 8). At gd20 arresting conceptus attachment sites were distinguished by decreased vasculature of the placental membranes and decreased conceptus size. At gd50 arresting conceptuses attachment sites were identified by smaller conceptus length and weight measurements. Quantitative real time PCR was used to determine relative transcript levels of genes of interest, and cellular localization was determined by immunohistochemistry in paraffin embedded endometrial sections.

RESULTS

At gd20, endometrial samples from arresting conceptuses had elevated transcripts for bFGF, and PDGF-bb than healthy sites (p < 0.05). At gd50, bFGF, FGFR2, and CD36 were more abundant at arresting than at healthy conceptus attachment sites (p < 0.05). Chorioallantoic membrane from arresting conceptus attachment sites at gd20 had elevated transcripts for bFGF, FGFR1, FGFR2 and CD36 compared with healthy sites (p < 0.05). FGFR2 transcripts were more abundant in chorioallantoic membrane from arresting conceptuses at gd 50 (p < 0.05). Immunohistochemical localization of selected pro- and anti-angiogenic factors and receptors revealed their abundance in the luminal epithelium, uterine glands and perivascular areas of endometrium at gd20 and gd50.

CONCLUSIONS

We provide comprehensive analysis of pro and anti-angiogenic factors at the porcine maternal fetal interface during early and mid-pregnancy. At mRNA levels, the majority of pro-angiogenic factors investigated were elevated at the sites of fetal arrest. These observations contrast with our previous findings of decreased Vascular Endothelial Growth Factor (VEGF) family members at arresting sites, and suggest that the bFGF family functions as a compensatory survival mechanism when major angiogenic proteins are decreasing at the sites of fetal arrest.

Cellular and molecular events in early and mid gestation porcine implantation sites: a review

Commercial, North American pork breeds (Sus scrofa) experience significant loss of genetically-normal conceptuses during the peri-implantation (attachment) period and at mid-gestation (day 50 to 90 of the 114 day porcine gestation interval). Although exact causes for these losses are not defined, asynchronous in-utero development and deficits in vascularization of the endometrium and placenta appear to be involved. Understanding of normal maternal-fetal dialogue is critical to develop breeding or therapeutic strategies that improve fetal health and overall litter size in commercial pigs. The non-invasive, epitheliochorial porcine placenta permits investigation of maternal or fetal compartments without cross contaminating cells. We developed and use protocols to capture single, homogenous populations of porcine cells (endometrial lymphocytes, dendritic or endothelial cells) from histological sections using laser capture microdissection (LCM), a powerful tool for study of gene expression that reflects the in vivo environment. These data are compared with gene expression in biopsies of endometrium and of trophoblast from the same, attachment sites. Here we review justifications for selection of the genes we have studied and our published and in progress work. These data provide new insights into the roles of the endometrial immune environment in the regulation of the success and failure of porcine conceptuses.

A review of molecular contrasts between arresting and viable porcine attachment sites

Significant spontaneous fetal loss of unknown cause occurs in North American commercial swine. About 30% of conceptuses, thought to be genetically normal, are lost during the peri-attachment period. An additional 20% are lost at mid-pregnancy. Littermate endometrial and trophoblast biopsies were studied by quantitative real-time PCR for gene expression, and immunohistochemistry for protein expression at gestation day (gd)15-23 and 50. RNA analyses were also conducted on endometrial lymphocytes and arterial endothelial cells removed from biopsies by laser capture microdissection. Genes were selected for study from human literature and cloned as required. As in humans, angiogenic, cytokine, chemokine and chemokine decoy receptor gene expression occurs at the porcine maternal-fetal interface. In each tissue studied, distinct patterns of expression are found between early and mid-pregnancy, as well as between viable and arresting conceptus attachment sites. These changes involve both endometrial lymphocytes and dendritic cells. Restriction in endometrial angiogenesis, reduction in expression of the chemokine decoy receptor D6, and reduction in dendritic cell numbers contribute to fetal arrest. In peri-attachment loss, interferon-gamma is more abundantly transcribed than tumor necrosis factor-alpha, but this ratio is reversed during midgestation failure. Further characterization of spontaneous fetal loss in pigs will identify targets for modification by hog producers and may provide a model for identification of antecedents to fetal loss in humans.

Immunological mechanisms affecting angiogenesis and their relation to porcine pregnancy success

Prenatal mortality due to loss of lymphocyte-promoted endometrial angiogenesis is being investigated as a major cause of litter reductions during pregnancy in pigs. This review discusses immune mechanisms influencing porcine endometrial angiogenesis as well as additional signalling molecules that may play important roles in the compromise of peri-implantation and mid-gestation fetal pig survival. These include dendritic cells, signalling molecules such as toll-like receptors, chemokines and ficolins. Together these cells and molecules regulate immune responses and, ideally, protect the mother and prevent immune-based conceptus losses. Dendritic cells were recently shown to be angiogenic. Their tolerogenic role at the maternal-fetal interface coupled with the ability to secrete and respond to angiogenic factors suggests that dendritic cells are the key coordinators of angiogenesis at the porcine maternal-fetal interface. Chemokines coordinate the localization of immune effector and endothelial cells. The balance between pro-angiogenic and anti-angiogenic chemokines is addressed in relation to conceptus viability. Ficolins, components of the lectin-mediated complement activation pathway, are used for self/non-self recognition. Together, these components of the immune system could regulate lymphocyte- and non-lymphocyte-promoted endometrial angiogenesis to determine conceptus survival.

Investigation of lipid peroxidation in liposomes induced by heavy ion irradiation

Lipid peroxidation induced by heavy ion irradiation was investigated in 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLPC) liposomes. Lipid peroxidation was induced using accelerated heavy ions that exhibit linear energy transfer (LET) values between 30 and 15000 keV/microm and doses up to 100 kGy. With increasing LET, the formation of lipid peroxidation products such as conjugated dienes, lipid hydroperoxides, and thiobarbituric acid-reactive substances decreased. When comparing differential absorption spectra and membrane fluidity following irradiation with heavy ions and x-rays (3 Gy/min), respectively, it is obvious that there are significant differences between the influences of densely and sparsely ionizing radiation on liposomal membranes. Indications for lipid fragmentation could be detected after heavy ion irradiation.

Gamma-irradiation and UV-C light-induced lipid peroxidation: a Fourier transform-infrared absorption spectroscopic study

Fourier transform-infrared spectroscopy of dry, multibilayer films has been used to study gamma-radiation and UV-C light induced lipid peroxidation in 1,2-dilinoleoyl-sn-glycero-3-phosphocholine liposomes. The observed spectral changes were compared with the results obtained from measurement of hydroperoxides, conjugated dienes and to the formation of thiobarbituric acid reactive substances, such as malondialdehyde (MDA) or MDA-like substances. Upon irradiation a decrease in intensity of the asymmetric C - H stretching vibration (va(CH2)) of the isolated cis C = C - H groups (3010 cm-1) was observed. Directly correlated with the decrease of the va(CH2) absorption was a shift of the asymmetric phosphate ester stretching vibration (va(P = O)) towards smaller wavenumbers (1260-->1244 cm-1), indicating that the lipid peroxidation induced molecular alterations in the fatty acid chains influence the packing of the phospholipids in dry multibilayer films. In addition, the formation of a new absorption band at 1693 cm-1 could be detected, the intensity of which was comparable with the formation of thiobarbituric acid reactive substances and, therefore, attributed to the (C = O) stretching of alpha, beta unsaturated aldehydes. Dose-dependent studies using ionizing radiation showed that the decrease of va(CH2) was directly correlated with an increase in absorption of the conjugated dienes at 234 nm and with the formation of hydroperoxides suggesting that the absorption at 3010 cm-1 is solely due to isolated cis C = C - H groups and hence subject to the early stages of the radical chain reaction. UV-C light induced lipid peroxidation revealed a non-linear decrease of I3010, which was directly correlated with the formation of hydroperoxides. The observed early saturation of the conjugated dienes was attributed to an early photodecomposition of the conjugated double bonds.

Photooxidation of tryptophan: O2(1 delta g) versus electron-transfer pathway

Tris (2,2'-bipyridyl)ruthenium(II)chloride hexahydrate (Ru[bpy]3(2+)) free in solution and adsorbed onto antimony-doped SnO2 colloidal particles was used as a photosensitizer for a comparison of the O2(1 delta g) and electron-transfer-mediated photooxidation of tryptophan (TRP), respectively. Quenching of excited Ru(bpy)3(2+) by O2(3 sigma g-) in an aerated aqueous solution leads only to the formation of O2(1 delta g) (phi delta = 0.18) and this compound was used as a type II photosensitizer. Excitation of Ru(bpy)3(2+) adsorbed onto Sb/SnO2 results in a fast injection of an electron into the conduction band of the semiconductor and accordingly to the formation of Ru(bpy)3(2+) and was used for the sensitization of the electron-transfer-mediated photooxidation. The Ru(bpy)3(3+) is reduced by TRP with a bimolecular rate constant kQ = 5.9 x 10(8) M-1 s-1, while O2(1 delta g) is quenched by TRP with kt = 7.1 x 10(7) M-1 s-1 (chemical + physical quenching). Relative rate constants for the photooxidation of TRP (kc) via both pathways were determined using fluorescence emission spectroscopy. With Np, the rate of photons absorbed, being constant for both pathways we obtained kc = (372/Np) M-1 s-1 for the O2(1 delta g) pathway and kc > or = (25,013/Np) M-1 s-1 for the electron-transfer pathway, respectively. Thus the photooxidation of Trp is more than two orders of magnitude more efficient when it is initiated by electron transfer than when initiated by O2(1 delta g).

Singlet oxygen luminescence spectra: a comparison of interferometer- and grating-based spectrometers

The current trend in methodology for determining IR and near-IR absorption spectra is to employ interferometer-based instruments to replace the monochromator-based devices used heretofore. As a dispersion element, the interferometer offers major improvements in spectral resolution (Connes advantage), light throughput (Jacquinot advantage) and data acquisition through multiplexing (Felgett advantage). We have compared signal-to-noise (S/N) ratios of grating-based and interferometer-based instruments for making spectral determinations of near-IR luminescence. Our results show that under identical excitation and detector conditions the interferometer instrument easily outperforms the grating, giving a 10-fold improvement in S/N at high signal amplitude (A488nm = 0.97) and a 20-fold improvement when the signal amplitude is low (A488nm = 0.06). Although some spectral resolution is sacrificed when scan times on the Fourier transform (FT)IR are significantly shortened, the S/N ratio was found only to decrease by a factor of 2 for a 10-fold decrease in scan time. This adds to the advantages of the FTIR technique because the S/N will thus improve for the same total acquisition time.

Flow cytometric detection of micronuclei by combined staining of DNA and membranes

A new staining method is presented for flow cytometric measurement of micronuclei (MN) in cell cultures and human lymphocytes using membrane-specific fluorescent dyes in addition to DNA staining. Several combinations of fluorescent membrane and DNA dyes were studied for a better discrimination of MN from debris in a suspension of nuclei and micronuclei. For staining of membranes, the lipophilic dyes 2-hydroxyethyl-7,12,17-tris(methoxyethyl)porphycene (HEPn) and 1,6-diphenyl-1,3,5-hexatriene (DPH) were used in combination with ethidium bromide (EB), proflavine (PF), and Hoechst 33258 (HO). Due to their spectral properties, HO or EB combined with HEPn were not as suitable for the discrimination of MN from debris as was HEPn in combination with PF. With HEPn in combination with PF, however, additional noise was found at low fluorescence intensities, probably due to free fluorescent dye molecules in the solution. The optimal simultaneous staining of membranes and DNA was obtained using a combination of DPH and EB. The induction of MN in Chinese hamster and mouse NIH-3T3 cells by UV-B illumination was studied with this new staining technique. UV-B illumination (280-360 nm) induced MN in both cell lines. Chinese hamster cells were found to be more sensitive to these wavelengths. Illumination with wavelengths above 360 nm did not induce MN in either cell line. The results obtained from human lymphocytes using the combination of EB and DPH were comparable to the results obtained with the combination of EB and HO.

Photodynamic antitumor agents: beta-methoxyethyl groups give access to functionalized porphycenes and enhance cellular uptake and activity

Porphycene photosensitizers bearing two or four methoxyethyl side chains were synthesized in nine steps from commercially available starting materials. Ether cleavage led to (hydroxyethyl)- and (bromoethyl)porphycenes that were converted to vinyl and benzo derivatives. Five of the side chain-functionalized porphycenes were biologically studied in comparison with two tetra-n-propylporphycenes. Porphycenes were incorporated in small unilamellar liposomes and incubated with cultivated SSK2 murine fibrosarcoma cells. Cellular uptake and phototoxicity 24 h after 5 J/cm2 laser light treatment were determined. The porphycenes tested were between 17 and 220 times more photodynamically active than the currently clinically used sensitizer Photofrin, although extinction coefficients of the porphycenes' irradiated bands are only approximately 10-fold higher. The LD50 concentration for SSK2 cells in the incubation medium was as low as (8.5 +/- 2.8) x 10(-9) M for tetrakis(methoxyethyl)porphycene. Two methoxy or hydroxy groups enhanced cellular uptake, three or four methoxy groups both enhanced and accelerated cellular uptake of tetraalkylporphycenes. Half-life times of the uptake processes varied between (0.14 +/- 0.04) and (14 +/- 4) h and cellular saturation levels between (1.2 +/- 0.2) and (26 +/- 3) pmol/10(5) cells. When individual uptake rates were accounted for, all porphycenes had a similar "cellular" phototoxicity, pointing toward a common mechanism of action. Evidence is presented for the assumption that cell membranes are the primary targets of the tested porphycenes and that membrane solubility may play a critical role in their photodynamic efficiency. The results show that nonionic polar side chain functionalities can strongly enhance cellular uptake and antitumor activity of lipophilic porphyrinoids and thus that the known lipophilicity/activity relationship can be reversed for very hydrophobic sensitizers.

Cell cycle kinetics of hematopoiesis before and after in vivo administration of GM-CSF in refractory anemia: evidence for a shortening of the granulocyte release time

GM-CSF administration to patients with refractory anemia (RA) induces an increase in neutrophils and eosinophils. We studied cell kinetic mechanisms underlying this observation using clonogenic assays and in vivo iododeoxyuridine labeling of bone marrow cells. Cell cycle kinetics were studied in three patients before and during GM-CSF administration (two daily subcutaneous injections of 54 or 108 micrograms). No consistent effect on the relative number of bone marrow CFU-GM was noticed. The DNA synthesis time and potential doubling time of low-density bone marrow cells remained essentially the same. A slight decrease (1.5-3.7%) in labeling index was found, originating from the myelo(-mono)cytic lineage. In all three patients the release time of labeled granulocytes from the bone marrow into the peripheral blood was shortened (before GM-CSF treatment 5-7 days and during GM-CSF 3-4 days). Cell cycle kinetics of CD34+ cells were studied in order to obtain kinetic information on immature precursor and progenitor cells. The DNA synthesis time of the CD34+ cells was shortened during GM-CSF therapy, resulting in a shorter potential doubling time. GM-CSF administration to patients with RA results in a rise in granulocytes that might be due partly to an accelerated release of granulocytes from the bone marrow compartment into the circulating blood and partly to an increased proliferative activity of the immature precursor and progenitor cells.

Photodegradation of protoporphyrin-dimethylester in solution and in organized environments

The degradation of sensitizers used in photodynamic therapy (PDT) involves photooxidation either by molecular oxygen or by oxygen intermediates which leads to hydroxyaldehyde and formyl products or to ring opening. Our investigations focused on the spectroscopic changes which protoporphyrin-dimethylester (PP) exhibits upon irradiation. As the microenvironment strongly influences the effects, we used an aprotic organic solvent, L-alpha-phosphatidylcholine dioleoyl (DOPC) liposomes and isogenic fibrosarcoma cells (SSKII) as carriers for PP. Hydroxyaldehyde product isomers develop a new absorption band centred around 670 nm and a new emission band at 676 nm. These characteristics can be used to discriminate them from formyl products and intact PP. In organic solvents, the formation of the hydroxyaldehyde products dominates. In DOPC liposomes and cells, the hydroxyaldehyde yield drops and photooxidation results in attack of the macrocycle. Time-resolved fluorescence spectroscopy of monomeric PP in an organic solvent gives a monoexponential decay time tau of 10.1 +/- 1.3 ns. Upon irradiation a second component with a decay time of 4.9 +/- 0.6 ns, resulting from the hydroxyaldehyde product, was detected. In liposomes and cells the monomeric decay time was significantly longer (15 ns) due to the altered microenvironment. Additionally, we observed in liposomes and in cells a small contribution of a short component (1 ns) which is attributed to an aggregated sensitizer species. In irradiated cells the aggregated fraction doubles, indicating a change in the microenvironment caused by the photodynamic action of the sensitizer.

Phonotactic knowledge of word boundaries and its use in infant speech perception

The development of a lexicon critically depends on the infant's ability to identify wordlike units in the auditory speech input. The present study investigated at what age infants become sensitive to language-specific phonotactic features that signal word boundaries and to what extent they are able to use this knowledge to segment speech input. Experiment 1 showed that infants at the age of 9 months were sensitive to the phonotactic structure of word boundaries when word-like units were presented in isolation. Experiments 2 to 5 demonstrated that this sensitivity was present even when critical items were presented in context, although only under certain conditions. Preferences for legal over illegal word boundary clusters were found when critical items were embedded in two identical syllables, keeping language processing requirements and attentional requirements low. Experiment 6 replicated the findings of Experiment 1. Experiment 7 was a low-pass-filtered version of Experiment 6 that left the prosody of the stimulus items intact while removing most of the distinctive phonotactic cues. As expected, no listening preference for legal over illegal word boundary clusters was found in this experiment. This clearly suggests that the preferential patterns observed can be attributed to the infants' sensitivity to phonotactic constraints on word boundaries in a given language and not to suprasegmental cues.

Chemosensitivity testing of xenografted squamous cell carcinomas of the head and neck region

Eight squamous cell carcinomas from the head and neck region were established as xenograft lines in nude mice and tested for their sensitivity to the antineoplastic drugs bleomycin and cisplatin. Tumor volume, histology, DNA flow cytometry and mitotic activity were used as parameters. One out of the 8 tumours appeared to be highly sensitive to bleomycin, while three other tumours were sensitive to both bleomycin and cisplatin. These observations are in good correlation with the reported data in patients. All chemosensitive tumours showed regrowth after the cytotoxic drug treatment had been completed. No change was seen in the chemosensitivity of other features of the regrown tumours, not even after repeated exposure to the drugs. Comparison of the tumour volume with the other parameters applied indicated that the tumour volume of squamous cell carcinomas was not always a reliable parameter for testing chemosensitivity, because of the important contribution of keratin to the tumour volume. It is concluded that additional parameters such as histological examination, DNA flow cytometry or mitotic activity are necessary in order to draw reliable conclusion on xenografts with a large avital component. In addition, DNA flow cytometry has proved to be very useful for the rapid screening of drug sensitivity.

Intracellular localization of meso-tetraphenylporphine tetrasulphonate probed by time-resolved and microscopic fluorescence spectroscopy

The effects of solvent pH on spectral properties and fluorescence decay kinetics were investigated in order to characterize the microenvironment of meso-tetraphenylporphine tetrasulphonate (TPPS4) taken up by cells. Steady-state absorption and fluorescence spectra of TPPS4 in buffer solutions of different pH were used to identify a ring protonated species at pH less than or equal to 4. This dictation could also be distinguished from the unprotonated form by its altered fluorescence decay time (3.5 vs. 11.4 ns). In addition, time-resolved spectroscopy gave some evidence of a monocationic species existing at pH 6-9. This was concluded from the occurrence of another component with a decay time of 5 ns. Measurements of the spectral and kinetic properties of the fluorescence emission of single epithelial cells (RR1022) incubated with TPPS4 indicated that the sensitizer was mainly localized in a microenvironment with a pH of 5, a value which occurs intracellularly only within lysosomes. Cells kept in the dark exhibited the characteristic spectra of both the dication and the neutral form. The fluorescence decay showed two components with decay times of 2.6 ns and 10.6 ns. Irradiation of the cells changed the decay times to 4.6 ns and 13.4 ns and the dication fluorescence emission peak vanished, which is in accordance with the results obtained from buffer solutions at pH greater than or equal to 6. Therefore, we deduce that the photodynamic action leads to a rupture of the lysosomes and that the sensitizer is released into the surrounding cytoplasm.

Effect of doxorubicin exposure on cell-cycle kinetics of human leukemia cells studied by bivariate flow cytometric measurement of 5-iodo-2-deoxyuridine incorporation and DNA content

Cell kinetics of two human leukemic cell lines, Molt-4 and K562, following a 2-h exposure to doxorubicin, were studied. DNA flow cytometry provided static information that for both cell lines a dose-dependent accumulation occurred at the G2 + M compartment that disappeared in time. Kinetic information was provided by time-monitoring cells labeled with 5-iodo-2-deoxyuridine (IdUrd) by two-parameter flow cytometry, analyzing the IdUrd label and the DNA content. The cell-cycle time (Tc) of exponentially growing Molt-4 cells was determined to be 20 h. Twenty-four hours after a 2-h exposure to 0.25 micrograms/ml doxorubicin, the Tc had increased to 23 h; following exposure to 1.0 micrograms/ml, it increased to 33 h. Cell kinetics of K562 cells following doxorubicin exposure were monitored in time up to 4 days. The average Tc of exponentially growing K562 cells was determined to be 24.7 h. Twenty-four hours following 2-h exposure to 0.25 or 0.5 micrograms/ml doxorubicin, the Tc were determined to be 28 and 32 h, respectively. After an additional 2 days, the Tc were both determined to be 24 h. The dose-dependent, reversible cell-cycle delay that persisted at least 48 h should be taken into account as an additional mode for decrease of a (tumor) cell population doubling time after exposure to doxorubicin.

Doxorubicin toxicity in relation to the proliferative state of human hematopoietic cells

The relation between the proliferative state of normal human hematopoietic cells and their sensitivity to doxorubicin was studied. T-lymphocytes were stimulated with phytohaemagglutinin/interleukin 2 before or after a 2-h exposure to doxorubicin (range 0-2 microgram/ml). The doxorubicin concentration that inhibited DNA synthesis in 50% of the lymphocytes, measured qualitatively with 5-iodo-2'-deoxyuridine incorporation, was significantly lower (a factor of 2.5) in case of drug exposure of stimulated lymphocytes compared to nonstimulated lymphocytes. These proliferation-dependent differences were not related to differences in cellular drug concentrations, as was determined with flow cytometry. Bone marrow cells were stimulated for 2 days with human placenta-conditioned medium before or after exposure to doxorubicin (range 0-2 microgram/ml), after which they were cultured in a bone marrow clonogenic assay. In analogy with the lymphocyte experiments, proliferation-dependent differences in drug sensitivity were found. The drug concentration that inhibited the growth of granulocyte-macrophage colonies (granulocyte-macrophage colony-forming units, CFU-GM) to 50% appeared significantly lower (a factor of 3.4) with drug exposure of stimulated bone marrow cells compared to nonstimulated bone marrow cells. The relative insensitivity of quiescent, but potentially proliferative cells to doxorubicin might explain the recovery of hematopoiesis after doxorubicin-induced bone marrow hypoplasia.

Modulation of the in vitro cytotoxicity of seven anticancer drugs by protein synthesis inhibition using sparsomycin

Inhibitors of protein synthesis may modify cell response to cytotoxic drugs. The influence of protein synthesis inhibition using sparsomycin (Sm) on the cytotoxicity of seven classical cytotoxic drugs, 5-FU, ARA-C, MTX, doxorubicin, melphalan, bleomycin and vincristine, was studied. Preincubations, simultaneous incubations and postincubations with Sm were investigated in vitro on CHO cells. Preincubation with Sm antagonized the activity of the S phase specific drugs 5-FU, ARA-C, MTX as well as vincristine, while postincubation with Sm enhanced their effect. A similar pattern was observed with doxorubicin. Preincubation with Sm had a potentiated non-S phase specific like bleomycin and cisplatin, but not melphalan. Postincubation with Sm had a potentiating effect on bleomycin but had no effect on melphalan. These results indicate a strong, schedule dependent effect of Sm on various drugs and suggest some potentially useful combinations to be tested in vivo.

Autologous transplantation of bone marrow purged in vitro with anti-CD7-(WT1-) ricin A immunotoxin in T-cell lymphoblastic leukemia and lymphoma

Seven patients with high-risk acute T-cell lymphoblastic leukemia (T-ALL) and six with T cell lymphoma (T-LL) were treated with autologous bone marrow transplantation (ABMT) after in vitro purging of their bone marrow with WT1 (CD7)-ricin A-chain immunotoxin. CD7 expression on the tumor cells showed large variations between the individual patients and was highly related to the specific cytotoxicity of WT1-ricin A. Incubation of bone marrow with up to 10(-8)mol/L WT1-ricin A in the presence of 6 mmol/L NH4Cl did not compromise the growth potential of the hematopoietic progenitors CFU-GM, CFU-GEMM, and BFU-E. Hematologic engraftment (greater than 10(9) leukocytes/L) occurred within a normal time period (median, 17 days). Seven patients are alive and in complete remission (CR) at 48+, 44+, 40+, 26+, 11+, 7+, and 6+ months after ABMT. Four patients relapsed within 6 months after ABMT. Two of them had the lowest CD7 expression on their tumor cells, the other two were transplanted in CR2 and CR3. Two patients died from transplantation related infections. The immunologic reconstitution was delayed, although the numbers of T cells reached normal levels within 1 month. The number of CD7+ cells remained low up to 1 year after transplantation. The T4/T8-ratio was decreased for at least 6 months. The T-cell response to mitogens recovered to normal levels after 1 year. This study shows that ABMT with WT1-ricin A purged bone marrow in high-risk T-cell malignancies results in a complete hematopoietic and a delayed immunologic reconstitution. The actuarial relapse free survival is 61% at 3 years.