Cytoplasmic maturation in human oocytes: an ultrastructural study †.

Female fertility relies on successful egg development. Besides chromosome segregation, complex structural and biochemical changes in the cytoplasmic compartment are necessary to confer the female gamete the capacity to undergo normal fertilization and sustain embryonic development. Despite the profound impact on egg quality, morphological bases of cytoplasmic maturation remain largely unknown. Here, we report our findings from the ultrastructural analysis of 69 unfertilized human oocytes from 34 young and healthy egg donors. By comparison of samples fixed at three consecutive developmental stages, we explored how ooplasmic architecture changes during meiotic maturation in vitro. The morphometric image analysis supported observation that the major reorganization of cytoplasm occurs before polar body extrusion. The organelles initially concentrated around prophase nucleus were repositioned toward the periphery and evenly distributed throughout the ooplasm. As maturation progressed, distinct secretory apparatus appeared to transform into cortical granules that clustered underneath the oocyte's surface. The most prominent feature was the gradual formation of heterologous complexes composed of variable elements of endoplasmic reticulum and multiple mitochondria with primitive morphology. Based on the generated image dataset, we proposed a morphological map of cytoplasmic maturation, which may serve as a reference for future comparative studies. In conclusion, this work improves our understanding of human oocyte morphology, cytoplasmic maturation, and intracellular factors defining human egg quality. Although this analysis involved spare oocytes completing development in vitro, it provides essential insight into the enigmatic process by which human egg progenitors prepare for fertilization.

Actual position of interleukin(IL)-33 in atherosclerosis and heart failure: Great Expectations or En attendant Godot?

Atherosclerosis has been recognized as an inflammatory/autoimmune disease. The long-standing low-grade inflammation which fuels its development is primarily focused on the components of the vessel wall. Originally, inflammation in atherogenesis was supposed to be driven by the pro-inflammatory Th1 cellular and cytokine immune response. On the basis of accumulating evidence, this view has been re-evaluated to include the Th17/Th1 axis which is shared by most diseases of sterile inflammation. The anti-inflammatory Th2 cellular and cytokine immune response is initiated concomitantly with the former two, the latter dampening their harmful reactions which culminate in full-blown atherosclerosis. Interleukin-33, a novel member of the IL-1 cytokine superfamily, was suggested to take part in the anti-atherogenic response by mediating the Th1-to-Th2 switch of the immune reactions. However, IL-33 is a multifaceted mediator with both pro- and anti-inflammatory activities, also called a "dual factor" or a "Janus face" interleukin. IL-33 occurs both in an extracellular (cytokine-like) and in a nuclear-bound (transcription factor-like) form, each of them performing distinct activities of their own. This review article presents the latest data relevant to IL-33's role in atherosclerosis and cardiac diseases as perceived by a cardiologist and a cardiac surgeon.

Inhibitory CD200R and proapoptotic CD95/CD95L molecules on innate immunity cells are modulated by cardiac surgery.

INTRODUCTION: Cardiac surgery directly initiates a systemic inflammatory response with the activation of both cellular and humoral parts of the immune system. Exaggerated immune system activation is associated with a risk of life-threatening multi-organ dysfunction (MOD) and increased morbidity and mortality in the postoperative period. The immune system response is regulated and terminated by inhibitory mechanisms, including the regulatory membrane molecules, such as CD200R, CD95, CD95L and soluble sCD200R. METHODS: We measured the expression of CD95, CD95L, CD200R and sCD200R molecules in granulocyte and monocyte populations in blood samples of 30 patients who underwent coronary artery bypass grafting (CABG) using cardiopulmonary bypass (CPB). Samples collected before surgery, after surgery and in the postoperative period were analyzed by flow cytometry and ELISA. RESULTS: We found a significant increase in the percentage of granulocytes featuring the anti-inflammatory molecule CD200R (from 5% to 17.8%) after surgery. We presume that these cells were less susceptible to apoptosis because they rarely expressed CD95 as the CD200R(+)CD95(-) granulocyte sub-population prevailed. Only a small percentage of CD200R(+) granulocytes expressed simultaneously CD95 (from 0.5 to 2.06 %). This small population of CD200R(+)CD95(+) cells decreased expression of CD200R after surgery and, thus, was likely to be a source of increased sCD200R in serum (from 96 to 294 ng/mL). Also, the expression of CD95L on CD200R(+) granulocytes and CD95 on CD200R(+) monocytes was affected by surgery. The percentage of CD200R(+) monocytes was elevated on the 1(st) postoperative day (from 30.6 to 49.4 %) and dropped below the preoperative value on the 7(th) day after surgery (from 30.6 to 19.8 %). This population comprised mainly CD200R(+)CD95(+) monocytes in which the enhanced expression of CD95 was found. CONCLUSION: Our data show that the expression of CD200R, CD95 and CD95L was influenced by cardiac surgery and imply the role of these membrane molecules in cell regulation-inhibition and apoptosis following cardiac surgery.

The long pentraxin PTX3: a candidate anti-inflammatory mediator in cardiac surgery.

Coronary artery bypass grafting (CABG) is performed with the use of cardiopulmonary bypass (CPB) and cardioplegic arrest (CA) of the heart. The advantage of this technique, alternatively referred to as "on-pump" surgery, resides, for the surgeon, in relatively easy access to and manipulation with the non-beating, bloodless heart. However, the advantage that is, thereby, gained by the patient is paid off by an increased susceptibility to postoperative systemic inflammatory response syndrome (SIRS). Under unfavorable conditions, the inflammatory syndrome may develop into life-threatening forms of MODS (multiple organ dysfunction syndrome) or even MOFS (multiple organ failure syndrome). Deliberate avoidance of CPB, also known as "off-pump" surgery, attenuates early postoperative inflammation throughout its trajectory of SIRS→MODS→MOFS, but, in the long run, there appears to be no substantial difference in the overall mortality rates. In the last years, our knowledge of the pathophysiology of surgical inflammation has increased considerably. Recent findings, highlighting the as yet rather obscure role of pentraxin 3 (PTX3) in these processes, are discussed in this review article.

Pentraxin 3(PTX 3): an endogenous modulator of the inflammatory response.

Inflammatory or anti-inflammatory? That is the question as far as the acute-phase response and its mediators, the pentraxins, are concerned. Only some ten years ago, the classical or short pentraxin C-reactive protein and the newly discovered long pentraxin PTX3 were considered to exert most of the detrimental effects of acute inflammation, whether microbial or sterile in origin. However, accumulating evidence suggests an at least dichotomous, context-dependent outcome attributable to the pentraxins, if not a straightforward anti-inflammatory nature of the acute-phase response. This paper is focused on the inherent effects of pentraxin 3 in inflammatory responses, mainly in coronary artery disease and in Aspergillus fumigatus infection. Both are examples of inflammatory reactions in which PTX3 is substantially involved; the former sterile, the latter infectious in origin. Apart from different inducing noxae, similarities in the pathogenesis of the two are striking. All the same, the introductory question still persists: is the ultimate impact of PTX3 in these conditions inflammatory or anti-inflammatory, paradoxical as the latter might appear? We try to provide an answer such as it emerges in the light of recent findings.

Interferon gamma receptor expression on granulocytes of cardiac surgical patients is modulated differently by the type of cardiopulmonary bypass used.

AIMS: To follow the IFNγ receptor expression on monocytes and granulocytes of cardiac surgical patients with respect to the type of cardiopulmonary bypass (CPB). METHODS: Expression of IFNγ receptor on monocytes and granulocytes of 26 cardiac surgical patients operated with the use of either "standard" or "miniaturised" CPB was determined by flow cytometry. RESULTS: The significant increase in IFNγ receptor expression on monocytes on the 1(st) and on the 3(rd) postoperative days was revealed in both groups of patients (p<0.001) irrespective of the type of CPB used, being non-significantly different between groups. In contrast, the expression of IFNγ on granulocytes displayed significant differences in terms of the CPB used. Whereas, in "standard" CPB patients, granulocyte INFγ receptor expression reached its maximum immediately after surgery (p<0.01), in "miniivasive" CPB patients, the peak in INFγ receptor expression was postponed to the 1(st) postoperative day (p<0.05). Statistically significantly higher IFNγ receptor expression on granulocytes was found in "standard" CPB patients (p<0.05). CONCLUSION: Compared to "miniaturised" CPB patients, the significantly higher IFNγ receptor expression on granulocytes was found in "standard" CPB patients (p<0.05) on the 1(st) postoperative day.

Interleukin-33, a novel member of the IL-1/IL-18 cytokine family, in cardiology and cardiac surgery.

Interleukin-33 is a newly recognized cytokine of the IL-1 family. Unlike its other members IL-1α, IL-1ß and IL-18, interleukin-33 induces predominantly Th2-skewed immune responses. In this context, the effects of IL-33 are mostly anti-inflammatory. However, depending on the actual cytokine and cellular milieu, IL-33 can promote both Th1 and Th2 immune reactions. Most importantly for cardiology and cardiac surgery, IL-33 has emerged to represent the as yet unknown ligand of the orphan receptor ST2. Before the advent of IL-33, the ST2 receptor, currently recognized as the soluble one of its two isoforms, was considered to be an unfavorable prognostic marker in myocardial infarction, congestive heart failure and trauma/sepsis shock patients. Now we know that IL-33, when bound to the cellular membrane-anchored ST2L isoform of the receptor, can have certain beneficial effects on the aforementioned conditions. Various forms of IL-33 interaction with the respective isoforms of its cognate receptor are discussed here. The focus is on physiological and prognostic values in cardiac patients.

Lineage specific composition of cyclin D-CDK4/CDK6-p27 complexes reveals distinct functions of CDK4, CDK6 and individual D-type cyclins in differentiating cells of embryonic origin.

OBJECTIVES: This article is to study the role of G(1)/S regulators in differentiation of pluripotent embryonic cells. MATERIALS AND METHODS: We established a P19 embryonal carcinoma cell-based experimental system, which profits from two similar differentiation protocols producing endodermal or neuroectodermal lineages. The levels, mutual interactions, activities, and localization of G(1)/S regulators were analysed with respect to growth and differentiation parameters of the cells. RESULTS AND CONCLUSIONS: We demonstrate that proliferation parameters of differentiating cells correlate with the activity and structure of cyclin A/E-CDK2 but not of cyclin D-CDK4/6-p27 complexes. In an exponentially growing P19 cell population, the cyclin D1-CDK4 complex is detected, which is replaced by cyclin D2/3-CDK4/6-p27 complex following density arrest. During endodermal differentiation kinase-inactive cyclin D2/D3-CDK4-p27 complexes are formed. Neural differentiation specifically induces cyclin D1 at the expense of cyclin D3 and results in predominant formation of cyclin D1/D2-CDK4-p27 complexes. Differentiation is accompanied by cytoplasmic accumulation of cyclin Ds and CDK4/6, which in neural cells are associated with neural outgrowths. Most phenomena found here can be reproduced in mouse embryonic stem cells. In summary, our data demonstrate (i) that individual cyclin D isoforms are utilized in cells lineage specifically, (ii) that fundamental difference in the function of CDK4 and CDK6 exists, and (iii) that cyclin D-CDK4/6 complexes function in the cytoplasm of differentiated cells. Our study unravels another level of complexity in G(1)/S transition-regulating machinery in early embryonic cells.