From Primary MSC Culture of Adipose Tissue to Immortalized Cell Line Producing Cytokines for Potential Use in Regenerative Medicine Therapy or Immunotherapy.

For twenty-five years, attempts have been made to use MSCs in the treatment of various diseases due to their regenerative and immunomodulatory properties. However, the results are not satisfactory. Assuming that MSCs can be replaced in some therapies by the active factors they produce, the immortalized MSCs line was established from human adipose tissue (HATMSC1) to produce conditioned media and test its regenerative potential in vitro in terms of possible clinical application. The production of biologically active factors by primary MSCs was lower compared to the HATMSC1 cell line and several factors were produced only by the cell line. It has been shown that an HATMSC1-conditioned medium increases the proliferation of various cell types, augments the adhesion of cells and improves endothelial cell function. It was found that hypoxia during culture resulted in an augmentation in the pro-angiogenic factors production, such as VEGF, IL-8, Angiogenin and MCP-1. The immunomodulatory factors caused an increase in the production of GM-CSF, IL-5, IL-6, MCP-1, RANTES and IL-8. These data suggest that these factors, produced under different culture conditions, could be used for different medical conditions, such as in regenerative medicine, when an increased concentration of pro-angiogenic factors may be beneficial, or in inflammatory diseases with conditioned media with a high concentration of immunomodulatory factors.

Activity of the human immortalized endothelial progenitor cell line HEPC-CB.1 supporting in vitro angiogenesis.

The human HEPC-CB.1 cell line with many characteristics of endothelial progenitor cells (EPC) was tested for its proangiogenic properties as a potentially therapeutic compound. HEPC-CB.1 cells' potential to differentiate into endothelial cells was revealed after treating the cells with a mixture of ATRA, cAMP and VEGF, as shown by the reduced expression levels of CD133, CD271 and CD90 antigens, augmentation of CD146 and CD31, and a decrease in cell clonogenicity. The cooperation of HEPC-CB.1 with the endothelial cell line HSkMEC.2 resulted in the formation of a common network. Tube formation was significantly more effective when resulting from HEPC-CB.1 and HSkMEC.2 cell co-culture as compared to a monoculture of each cell line. The exocrine mechanism of HEPC-CB.1 and HSkMEC.2 cross talk by secreted factors was evidenced using the HEPC-CB.1 supernatant to increase the efficacy of HSkMEC.2 tube formation. The proangiogenic factors produced by HEPC-CB.1 were identified using cytokine antibody array. Out of 120 examined factors, the HEPC-CB.1 cell line produced 63, some with known angiogenic activity. As in vivo the angiogenic process occurs at low oxygen tension, it was observed that in hypoxia, the production of defined factors was augmented. The presented results demonstrate that HEPC-CB.1 cells are able to both cooperate and integrate in a newly formed network and produce factors that help the network formation. The results suggest that HEPC-CB.1 cells are indeed endothelial progenitors and may prove to be an effective tool in regenerative medicine.

MRP1 protein expression in leukemic stem cells as a negative prognostic marker in acute myeloid leukemia patients.

BACKGROUND: It is well established that expression of multi-drug resistance (MDR) proteins (MDR1, BCRP, MDR3, MRP1, and LRP) in leukemic blasts correlates with acute myeloid leukemia (AML) patients' clinical response. Assuming that leukemic stem cells (LSC) are resistant to chemotherapy and responsible for relapse, it might be clinically relevant to evaluate the expression level of MDR proteins in LSC and relate it to the clinical outcome. METHODS: Bone marrow samples from 26 patients with de novo AML were labeled with antibodies to distinguish CD34+CD38-CD123+ LSC population and with antibodies against MDR1, BCRP, MDR3, MRP1, or LRP proteins. Multicolor flow cytometry was applied to evaluate the expression of MDR proteins in blasts and LSC. RESULTS: Nine of 26 patients with AML attained CR (30%). High negative correlation was found between MDR1 and LRP expression in blasts and the patient's remission. MDR proteins were expressed more frequently in LSC than in leukemic blasts. High negative correlation was also observed between remission achievement and MRP1 expression in LSC. CONCLUSIONS: Our data present for the very first time the high negative correlation between MRP1 protein expression in LSC and AML patients' remission. It does strongly suggest that MRP1 expression in LSC is an adverse prognostic marker in patients with de novo AML.

Increased Endothelial Progenitor Cell Number in Early Stage of Endometrial Cancer.

OBJECTIVES: It is generally believed that circulating endothelial cells (CECs) and endothelial progenitor cells (EPCs) reflect the state of the endothelium, its injury and/or repair possibilities. In different types of cancers, increased numbers of CECs and EPCs were found, suggesting their participation in cancer angiogenesis. The objective of this study was to determine whether, in the blood circulation of women with early endometrial cancer, CEC and EPC levels differ from those of healthy women of similar age. METHODS: For CEC number evaluation, samples of peripheral blood cells of women with endometrial carcinoma and control subjects were labeled with anti-CD31 and anti-CD45 antibodies; for EPCs, with anti-VEGFR2 (vascular-endothelium growth factor receptor 2)/KDR and anti-CD34 antibodies. The CEC and EPC cells were then quantified by flow cytometry. RESULTS: Endothelial progenitor cell numbers (CD34, VEGFR2/KDR) in the peripheral blood of women with endometrial carcinoma were significantly augmented as compared with those of control healthy women and CEC numbers (CD31, CD45) were similar in both groups. Cancer patients were divided according to the grading into G1 and G2 groups and according to the stage into International Federation of Gynecology and Obstetrics (FIGO) stage IA and FIGO IB groups. Statistically significant augmented EPC numbers were demonstrated only in G1 and FIGO IA patients. CONCLUSIONS: These results strongly suggest new vessel formation from recruited endothelial precursors as being involved mainly at the early stages of tumor progression.

[Natural killer cells complot with dendritic cells]. / Zwiazki komórek NK z komórkami dendrytycznymi.

Dendritic cells (DC) were initially considered as antigen presenting cells participating in the polarization of the immune response. Further understanding of their biology allowed determining their additional functions such as immunoregulatory and cytotoxicity. Until recently natural killer (NK) cells were known as a homogeneous population of lymphocytes capable of non-specific recognizing and eliminating target cells. Now it is widely accepted that NK cells, as a heterogeneous population, may also possess immunomodulatory functions. Moreover, the most recent analysis of the interactions between DC and NK cells revealed the exceptional functions of these cells. As a result of these studies the existence of bitypic cell population was postulated. The distinguishing features of these hybrid cells are: the expression of surface receptors typical for NK cells and DC, the cytotoxic activity, the production of interferons as well as their ability to present antigen after prior stimulation. Despite the lack of strong direct evidence that the same cell can be both cytotoxic and effectively present the antigen at the same time, there are experimental findings suggesting that generated ex vivo bitypic cells may be used in antitumor therapy. 

Prognostic value of the Fas/Fas ligand system in breast cancer.

Fas and its ligand (FasL) are known to play a crucial role in the genetically controlled mechanism of cell death, and their deregulation in cancer cells is involved in the immune escape of the tumor. The aim of this review is to analyze the current knowledge on the prognostic value of Fas/FasL in breast cancer patients. Both the results of other authors and our own experiences indicate that the lack of Fas ligand, and particularly Fas, is related to a significantly worse prognosis. It probably results from the resistance of Fas-deficient breast tumors to the mechanisms of apoptosis. On the other hand, some results suggest that the Fas/FasL-dependent mechanisms of tumor spread may be different for various target tissues. The expression of the Fas/Fas-ligand system has potential prognostic application in view of current knowledge, and consequently should be considered as an additional prognostic factor in breast cancer patients.

Multidrug resistance reversal and apoptosis induction in human colon cancer cells by some flavonoids present in citrus plants.

Multidrug resistance (MDR) of cancer cells constitutes one of the main reasons for chemotherapy failure. The search for nontoxic modulators that reduce MDR is a task of great importance. An ability to enhance apoptosis of resistant cells would also be beneficial. In the present study, the MDR reversal and apoptosis-inducing potency of three flavonoids produced by Citrus plants, namely, naringenin (1a), aromadendrin (2), and tangeretin (3), and the methylated naringenin derivatives (1b, 1c), have been studied in sensitive (LoVo) and multidrug-resistant (LoVo/Dx) human colon adenocarcinoma cells. Cytotoxicity of methoxylated flavonoids was higher as compared to hydroxylated analogues. Only 3 turned out to inhibit P-glycoprotein, as demonstrated by a rhodamine 123 accumulation assay. It also increased doxorubicin accumulation in LoVo/Dx cells and enabled doxorubicin to enter cellular nuclei. In addition, 3 was found to be an effective MDR modulator in resistant cells by sensitizing them to doxorubicin. Tangeretin-induced caspase-3 activation and elevated surface phosphatidylserine exposure demonstrated its apoptosis-inducing activity in LoVo/Dx cells, while the other flavonoids evaluated were not active. Additionally, 3 was more toxic to resistant rather than to sensitive cancer cells. Its apoptosis-inducing activity was also higher in LoVo/Dx than in LoVo cells. It was concluded that the activity of 3 against multidrug-resistant cancer cells may be enhanced by its apoptosis-inducing activity.

Reduced number of circulating endothelial progenitor cells (CD133+/KDR+) in patients with plaque psoriasis.

BACKGROUND: Psoriasis is associated with an increased cardiovascular risk. Circulating endothelial progenitor cells (CEPCs) play a significant role in the maintenance of vascular homeostasis. OBJECTIVE: The aim of this study was to evaluate the number of CEPCs in patients with psoriasis compared to controls and assess possible correlations between the number of these cells and the plasma levels of vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and clinical features of psoriasis. METHODS: The number of CEPCs, identified as CD133+/KDR+ cells, was determined with flow cytometry in peripheral blood of psoriatic patients (n = 63) and controls (n = 31). The plasma levels of VEGF and sVEGFR-1 were measured with enzyme-linked immunosorbent assay. RESULTS: The number of CEPCs was significantly reduced in psoriatic patients compared with controls (p = 0.000026) and inversely correlated with disease severity (R = -0.283; p = 0.0248). CONCLUSION: A reduced number of CEPCs may contribute to endothelial dysfunction in patients with psoriasis.

CD133 positive progenitor endothelial cell lines from human cord blood.

Endothelial progenitor cells (EPCs) modulate postnatal vascularization and contribute to vessel regeneration in adults. Stem cells and progenitor cells were found in umbilical cord blood, bone marrow, and mobilized peripheral blood cells, from where they were isolated and cultured. However, the yield of progenitor cells is usually not sufficient for clinical application and the quality of progenitor cells varies. The aim of the study was the immortalization of early progenitor cells with high proliferative potential, capable to differentiate to EPCs and, further, toward endothelial cells. Two cell lines, namely HEPC-CB.1 and HEPC-CB.2 (human endothelial progenitor cells-cord blood) were isolated. As assessed by specific antibody labeling and flow cytometric analysis, they express a panel of stem cell markers: CD133, CD13, CD271, CD90 and also endothelial cell markers: CD202b, CD309 (VEGFR2), CD146, CD105, and CD143 but they do not present markers of finally differentiated endothelial cells: CD31, vWf, nor CD45 which is a specific hematopoietic cell marker. Using the multiplex Cytometric Bead Assay, the simultaneous production of proangiogenic cytokines IL8, angiogenin, and VEGF was demonstrated in normoxia and was shown to be increased by hypoxia. Both cell lines, similarly as mature endothelial cells, underwent in vitro pre-angiogenic process, formed pseudovessel structures and present an accelerated angiogenesis in hypoxic conditions. To date, these are the first CD133 positive established cell lines from human cord blood cells.

Autotransplantation of the Adipose Tissue-Derived Mesenchymal Stromal Cells in Therapy of Venous Stasis Ulcers.

Adipose tissue is a reliable source of mesenchymal stromal cells (MSC) for use in regenerative medicine. The aim of this pilot study was to describe the method, and assess the safety and the potential efficacy of transplantation of autologous adipose tissue-derived MSC for the treatment of chronic venous stasis ulcers. Study group consisted of 11 patients (mean age: 66.6 ± 9.5 years) with chronic venous stasis ulcers. Adipose tissue was harvested by tumescent-aspiration method. Stromal cells were separated using a dedicated closed system in a real-time bedside manner. The phenotype of cells was determined immediately after separation. Cell concentrate was implanted subcutaneously around the wound and the wound bed. All ulcers were assessed planimetrically before autotransplantation and every two weeks during the six-month follow-up. During the study all patients received standard local and general treatment. The preparation contained an average of 5.6 × 106 ± 4 × 106 cells per milliliter. The phenotype of 65-82% of transplanted cells expressed MSC markers: CD73+ CD90+ and CD34+. An improvement was observed in 75% of ulcers. The data showed highly significant negative correlation (p < 0.0001) between wound size and wound closure degree. There was no correlation of ulcer healing with other parameters evaluated, including age of the patients. No serious side effects were observed. Autotransplantation of adipose tissue stromal cells may be a safe and promising treatment method for chronic venous ulcers.

Selective human endothelial cell activation by chemokines as a guide to cell homing.

An original model of organo-specific, immortalized and stabilized endothelial cell lines was used to delineate the part played by some chemokines (CCL21, CX3CL1, CCL5 and CXCL12) and their receptors in endothelium organo-specificity. Chemokine receptor expression and chemokine presentation were investigated on organo-specific human endothelial cell lines. Although the chemokines showed distinct binding patterns for the various endothelial cell lines, these were not correlated with the expression of the corresponding receptors (CX3CR1, CXCR4, CCR5 and CCR7). Experiments with CCL21 on peripheral lymph node endothelial cells demonstrated that the chemokine did not co-localize with its receptor but was associated with extracellular matrix components. The specific activity of chemokines was clearly shown to be related to the endothelial cell origin. Indeed, CX3CL1 and CCL21 promoted lymphocyte recruitment by endothelial cells from the appendix and peripheral lymph nodes, respectively, while CX3CL1 pro-angiogenic activity was restricted to endothelial cells from the appendix and skin. The high specificity of the chemokine/endothelium interaction allowed the design of a direct in vitro endothelial cell targeting assay. This unique cellular model demonstrated a fundamental role for chemokines in conferring on the endothelium its organo-specificity and its potential for tissue targeting through the selective binding, presentation and activation properties of chemokines.

Tumour antigen-loaded mouse dendritic cells maturing in the presence of inflammatory cytokines are potent activators of immune response in vitro but not in vivo.

The use of dendritic cells (DCs) loaded with tumour antigen is one of the most promising approaches to induce tumour-specific immune response. However, methods of the vaccine preparation have not yet been standardized. The purpose of the study was to analyse the anti-tumour efficacy of tumour antigen-loaded mouse bone marrow-derived dendritic cells (BM-DC/TAg) at different maturation stages. BM-DCs were loaded with MC38 colon carcinoma cell lysate (TAg) alone, to become partially differentiated, or were additionally stimulated with inflammatory cytokines such as TNF-alpha, IFN-gamma, or IL-12 to reach complete maturity. BM-DCs simultaneously stimulated with TAg and cytokines (especially IL-12 or IFN-gamma+IL-12) were in vitro more effective immune response activators than BM-DC/TAg cells. However, the highest anti-tumour effect in vivo was noted when mice were treated just with BM-DC/TAg. In a further study, the ability of IL-12 gene transduced BM-DCs (BM-DC/IL-12) to augment the immune response induced by BM-DC/TAg cells at different stages of maturation was examined. The highest anti-tumour effect was observed when partially differentiated BM-DC/TAg cells were injected simultaneously with BM-DC/IL-12 cells. The results suggest that partially differentiated BM-DC/TAg cells are more potent in evoking a strong anti-tumour response in vivo than mature BM-DCs. Moreover, the capacity of BM-DC/TAg cells for further differentiation and their sensitivity to factors secreted in vivo by the host or cells engineered to cytokine production seem to be of great importance.

Bacteriophages support anti-tumor response initiated by DC-based vaccine against murine transplantable colon carcinoma.

Bacteriophages in eukaryotic hosts may behave as particulate antigens able to activate the innate immune system and generate adaptive immunity. Dendritic cells (DCs) play a key role in the initiation of the immune response, mainly by priming T cell-mediated immunity. For this reason, they are increasingly applied as an adjuvant for effective anti-tumor therapies in animal models as well as in a few clinical trials. The presented study focused on the application of mouse DCs which were activated with T4 bacteriophages (T4 phages, T4) and further loaded with tumor antigens (TAg) in inducing an anti-tumor response. The activation of bone marrow-derived DCs with T4 phages and TAg resulted in augmentation of their differentiation marker expression accompanied by an enhanced ability to prime T cells for IFN-gamma production. These activated DCs (BM-DC/T4+TAg) were used in experimental immunotherapy of C57BL/6 mice bearing advanced MC38 colon carcinoma tumors. As a result of their triple application, a significant tumor growth delay, up to 19 days, was observed compared with the controls - treated with BM-DCs activated only with T4 phages, TAg, or lipopolysaccharide solution ["solvent"], where the tumor growth delay did not exceed 7 days. The percentage of tumor growth inhibition estimated 10 days after the third cell injection ranged from 32% (for animals treated with BM-DC/TAg cells) to 76% (for animals treated with BM-DC/T4+TAg cells) over the tumor-bearing untreated control mice. The obtained data indicate that in vitro interactions between T4 phages and BM-DCs followed by TAg activation caused augmentation of the anti-tumor effect when DCs were used as a vaccine for tumor-bearing mice treatment. Therefore, pretreatment of DCs with the phages may be considered as a beneficial element of a novel strategy in anti-tumor immunotherapy.

The variety of complexes formed by EcR and Usp nuclear receptors in the nuclei of living cells.

The heterodimer of the ecdysone receptor (EcR) and ultraspiracle (Usp), members of the nuclear receptor superfamily, is considered to be functional receptor for the ecdysteroids that coordinate essential biological processes in insects. In this work we have applied a bimolecular fluorescence complementation (BiFC) method to directly analyze the formation of the EcR/Usp complex. The BiFC experiments were carried out in mammalian cells which are routinely used for heterologous studies of the EcR/Usp complex, including experiments on EcR-based artificial molecular gene switches. BiFC analysis, supported by flow cytometry, revealed that EcR-Usp interaction is nuclei-restricted. If expressed separately, Usp and EcR are able to form nuclear complexes in the absence of the cognate dimerization partner. We have observed that Muristerone A that is widely used for the induction of ecdysteroid-dependent transcription in mammalian cells, does not significantly change the number of EcR/Usp and EcR/EcR complexes, and it does not influence their subcellular localization.

Flow cytometric assay for quantitative and qualitative evaluation of adhesive interactions of tumor cells with endothelial cells.

The purpose of the study was to develop a flow cytometric assay for quantitative determination of adhesive interactions of human endothelial cells (ECs) with tumor cells. EC lines established from human lymph node, appendix, lung, skin and intestine microvessels, labeled with PKH26-GL fluorescent dye, were grown to confluency in 24-well TC plates. Human colon adenocarcinoma cell suspension was overlaid onto labeled ECs, and allowed to adhere for 20 min at 4 degrees C under static conditions. Non-adhering cells were collected first, and adhering tumor cells together with ECs were detached from the culture plate. Collected cell fractions were evaluated by flow cytometry. Results were re-calculated as a ratio (R) of adhering colon carcinoma cells per one EC. We demonstrated that immortalized human microvascular ECs preserved their organ specificity. Colon carcinoma cells adhere preferentially to ECs of intestine origin. The immunofluorescent staining of adhering and non-adhering cancer cell subpopulations has revealed an augmented level of Lewis(x) antigen on adhering cancer cells. The organ specificity of endothelial cell interactions with colon carcinoma cells demonstrated in static conditions was verified and confirmed with flow adhesion assay. The method elaborated is suitable for quantifying of tumor cells adhering to ECs, with simultaneous evaluation of cell surface phenotypic markers of both partner cells participating in adhesive interactions. Validated by comparison to dynamic shear stress adhesion assay in blood flow reconstituted conditions this assay greatly facilitates evaluation of tumor cell-endothelial cell mutual interactions taking place during metastatic process.

Generation of anti-tumor response by JAWS II mouse dendritic cells transduced with murine interleukin 12 genes.

Murine dendritic cells (DCs) of the established JAWS II cell line were transduced with a retroviral vector carrying murine interleukin 12 (IL-12) genes (JAWS II/IL-12 cells). The JAWS II/IL-12 cells produced approximately 9-18 ng IL-12 protein/ml/5 x 10(5) cells/48 h and displayed an increased CD80 and CD86 expression as well as major histocompatibility complex antigen up-regulation. The JAWS II/IL-12 cells were used as a temporary source of IL-12 for the immunotherapy of C57BL/6 mice bearing transplantable murine colon carcinoma (MC38). The cell vaccines were administered according to different application schedules into the vicinity of subcutaneously growing palpable MC38 tumors. The JAWS II/IL-12 cells were delivered alone or in combination with JAWS II cells pulsed with MC38 tumor cell lysate (TAg) (JAWS II/TAg cells). The anti-tumor response was estimated as the tumor growth delay--the time (days) required for the tumor to reach a volume of 1 cm3 (TRV), and as the increase in animal life-span (ILS). Mice treated with three consecutive injections of JAWS II/IL-12 or JAWS II/TAg cells responded with moderate tumor growth delay (up to 6.5 and 9.5 days, respectively). After the administration of the JAWS II/IL-12 and JAWS II/TAg cell combination, the TRV was prolonged up to 12.5 days and there was a long-lasting tumor growth delay. Increasing the number of DC-based vaccines to four, resulted in the ILS extension of up to 87% over the control. A similar effect was observed when the vaccine containing the combination of both DC components was delivered prior to the three consecutive injections of JAWS II/IL-12 or JAWS II/TAg cells administered independently. The JAWS II/IL-12 cell vaccination of MC38 tumor-bearing mice was accompanied by an increased percentage of IFN-gamma-producing CD8+ spleen cells. Concluding, JAWS II DCs transduced with IL-12 genes could be used as an adjuvant vaccine for immuno- as well as combined immuno-chemotherapy of experimental tumors.

Fas/Fas-ligand expressions in primary breast cancer are significant predictors of its skeletal spread.

BACKGROUND: Bones belong to the most frequent localizations of breast cancer metastases. Several studies on female breast malignancies have indicated that Fas/Fas-ligand status may have a significant impact on survival. Hence, the aim of our study was to determine if these molecules might serve as the predictors of skeletal dissemination in radically-treated breast cancer patients. PATIENTS AND METHODS: Tumor samples from 147 radically-treated breast cancer patients were studied immunohistochemically for Fas/Fas-ligand expression. RESULTS: Both Fas and Fas-ligand expression in the primary tumor were considerably less frequent among breast cancer patients with bone metastases compared to women without skeletal spread. Moreover, negative staining for Fas or the lack of Fas-ligand expression proved to be significant predictors for the survival free from bone metastases under univariate analysis. CONCLUSION: Our results suggest that the probability of bone metastases may be assessed on the basis of Fas/Fas-ligand expression in primary breast cancer. Consequently, their determination seems crucial for further prognosis and determination of adjuvant treatment.

Evaluation of prognostic value of VEGF-C and VEGF-D in breast cancer--10 years follow-up analysis.

UNLABELLED: The aim of the study was to evaluate the prognostic value of vascular endothelial growth factor C (VEGF-C) and VEGF-D expression in stage II, grade 2 and 3, ductal breast cancer patients. PATIENTS AND METHODS: The immunohistochemical staining of 98 tumor samples and 5- and 10-year overall (OS) and disease-free survival (DFS) were analyzed. RESULTS: A significant relationship between VEGF-C and VEGF-D expression (p=0.000002) was noted. No correlations between protein expression and clinical parameters (tumor size, grade, estrogen receptor status, axillaty lymph node metastases and age) or 5- and 10-year DFS or OS were demonstrated. A close to significant correlation (p=0.084) was observed between high expression of VEGF-C and 5-year OS. CONCLUSION: Our study did not reveal any prognostic value of VEGF-C or VEGF-D. Therefore they are not useful as markers for patients with poor prognosis. Unlike in other studies, our patient group was homogenous which might have contributed to the results obtained.

[The role of endothelium in the pathogenesis of pregnancy-induced hypertension]. / Rola sródblonków w patogenezie nadcisnienia indukowanego ciaza.

Pregnancy-induced hypertension (PIH) is the major cause of maternal and perinatal morbidity. However, the mechanisms responsible for PIH pathogenesis have not yet been fully elucidated. The known risk factors of PIH development are: multiple pregnancy, masculine sex of fetus, very young age of women (below 18 years), advanced age (above 40 years), and obesity of the pregnant woman. In this article an attempt is made to summarize recent knowledge of the pathogenesis of PIH and, particularly, the postulated link between placental ischemia and microvascular dysfunction. The initiating event in PIH has been implicated to be reduced uteroplacental perfusion as a result of abnormal extravillous cytotrophoblast invasion. Focal ischemia and hypoxia, deportation of hypoxemic trophoblast cells, and abnormal expression of various placental biological molecules, particularly the cytokines, are thought to lead to widespread activation/dysfunction of the maternal vascular endothelium. The increased expression of adhesion molecules on activated endothelium intensifies the inflammation process and causes further endothelial injury. The quantitative importance of the various endothelial and humoral factors in mediating PIH symptoms is still unclear. Some of the factors that activate and damage endothelial cells may be of prognostic significance; however, more intensive research should be performed for a precise description of their predictive value.