Locating Functionalized Gold Nanoparticles Using Electrical Impedance Tomography.

OBJECTIVE: An imaging device to locate functionalised nanoparticles, whereby therapeutic agents are transported from the site of administration specifically to diseased tissues, remains a challenge for pharmaceutical research. Here, we show a new method based on electrical impedance tomography (EIT) to provide images of the location of gold nanoparticles (GNPs) and the excitation of GNPs with radio frequencies (RF) to change impedance permitting an estimation of their location in cell models Methods: We have created an imaging system using quantum cluster GNPs as contrast agent, activated with RF fields to heat the functionalized GNPs, which causes a change in impedance in the surrounding region. This change is then identified with EIT. RESULTS: Images of impedance changes of around 80 ± 4% are obtained for a sample of citrate stabilized GNPs in a solution of phosphate-buffered saline. A second quantification was carried out using colorectal cancer cells incubated with culture media, and the internalization of GNPs into the colorectal cancer cells was undertaken to compare them with the EIT images. When the cells were incubated with functionalised GNPs, the change was more apparent, approximately 40 ± 2%. This change was reflected in the EIT image as the cell area was more clearly identifiable from the rest of the area. SIGNIFICANCE: EIT can be used as a new method to locate functionalized GNPs in human cells and help in the development of GNP-based drugs in humans to improve their efficacy in the future.

Exploring strengths and limits of urinary D-chiro inositol phosphoglycans (IPG-P) as a screening test for preeclampsia: A systematic review and meta-analysis.

Preeclampsia is a severe complication of human pregnancy as it leads to significant maternal and perinatal mortality and morbidity worldwide. A prompt recognition of women that develop this syndrome can improve clinical management, increase surveillance and, finally, improve outcomes. Different methods (based on history, ultrasound, serum and urinary biomarkers) were proposed a screening tests for this disease but their performance showed limited results. Urinary inositol phosphoglycans P-type (IPG-P) were shown to identify in advance most of the women who will develop preeclampsia in case-control and longitudinal studies, so we undertook a systematic review and meta-analysis of published studies. Seven studies met the entry criteria so were evaluated. All case-control studies showed excellent statistical performances in a quality statistical assessment. The meta-analysis considered three longitudinal, prospective studies that showed high sensitivity and specificity with ranges of 0.82- 0.99 and 0.90-1.00, respectively. Univariate measures of accuracy revealed a positive and negative likelihood ratio respectively of 3.61 (95% CI 1.56-5.67) and -2.35 (95% CI -3.79 to -0.91). By univariate approach, we found a pooled logarithm of diagnostic odds ratio of 6.15 (95% CI 2.64-9.67). A limitation of this analysis is that, although conducted in different settings (UK, Italy, France, South Africa, and Mauritius) and different clinical groups, they were based on a single academic group. According to our findings, IPG-P test showed very encouraging results as a rapid noninvasive screening test for preeclampsia. Further studies are needed to verify and to validate the reported findings.

New insights into early and late onset subgroups of preeclampsia from longitudinal versus cross-sectional analysis of urinary inositol-phosphoglycan P-Type.

Most pre-eclampsia (PE) studies have used cross-sectional data to derive conclusions regarding the pathophysiology of the condition. This has led to the concept that there exists early (<34 weeks) and late-onset (>34 weeks) disease according to gestational age at diagnosis. Survival time models have predicted that if the pregnancy was to continue indefinitely, all women would develop PE. In this study we have performed a longitudinal analysis of the urinary biomarker, inositol phosphoglycan (IPG), in a cohort of women giving birth in Mauritius (n-920). We have analysed the PE data in the traditional cross-sectional manner for n = 77 women who developed PE and also then looked at the longitudinal data for 71/77 of the same women. The data allows us to use longitudinal values to calculate a date of onset (first presence of biomarker in urine) and compare that to date of clinical diagnosis (cross sectional). We find two populations for both analysis consistent with an early and late stage subgroup. The calculated date of onset had subgroups (early and late) at 28.4 ±â€¯0.41 weeks and 35.37 ±â€¯0.26 weeks and for clinical date of diagnosis, 32.3 ±â€¯0.59 weeks and 37.04 ±â€¯0.62 weeks, respectively. The presence of the same biomarker in both subgroups and its ability to predict clinical onset 2-4 weeks prior to clinical diagnosis suggest that both groups may have similar aetiology.

Putative Key Role of Inositol Messengers in Endothelial Cells in Preeclampsia.

Immunological alterations, endothelial dysfunction, and insulin resistance characterize preeclampsia. Endothelial cells hold the key role in the pathogenesis of this disease. The signaling pathways mediating these biological abnormalities converge on PKB/Akt, an intracellular kinase regulating cell survival, proliferation, and metabolism. Inositol second messengers are involved in metabolic and cell signaling pathways and are highly expressed during preeclampsia. Intracellular action of these molecules is deeply affected by zinc, manganese, and calcium. To evaluate the pathophysiological significance, we present the response of the intracellular pathways of inositol phosphoglycans involved in cellular metabolism and propose a link with the disease.

Urinary inositol phosphoglycan-P type: near patient test to detect preeclampsia prior to clinical onset of the disease. A study on 416 pregnant Mauritian women.

Preeclampsia and eclampsia account for major pregnancy complications in Mauritius, an emerging country (maternal mortality rate of 60 per 100,000 deliveries). This prospective longitudinal study was carried out in the main regional hospital in the north of the island, to measure inositol phosphoglycan-P type (IPG-P) in the urine of pregnant women (using an ELISA-based assay). Women had approximately 10 prenatal visits per pregnancy and a complete follow-up in this same referral centre after the first trimester of pregnancy. Urine samples were collected every 1-4 weeks in all women. In a cohort of 416 patients, preeclampsia (PE) was diagnosed in 34 women. In established PE (hypertension and proteinuria), the assay as a diagnostic test showed a positive likelihood ratio of 18.73, a negligible negative likelihood ratio with area under the curve (AUC) of 0.99, sensitivity of 96.7%, specificity of 94.8% and remained negative in control women (n=312), women with gestational hypertension (without proteinuria (n=56), and gestational diabetic mothers (n=14). Moreover, as a predictive screening test two weeks before the diagnosis of PE, the assay showed sensitivity of 84.2% and specificity of 83.6%. Detection of urinary inositol phosphoglycan-P type in pregnant women can be a useful confirmatory marker of PE, as well as a predictive marker, two weeks before the onset of the disease.

Inositol phosphoglycan P-type in infants of preeclamptic mothers.

BACKGROUND: Inositol phosphoglycan P-type (P-IPG) has consistently found to be elevated during active preeclampsia, although the biosynthetic source has to be identified yet. This multicenter prospective cross-sectional case-control study evaluated the fetus/newborn as the source of P-IPG. METHODS: A urine specimen was collected longitudinally for three consecutive days after delivery from 90 newborns and their mothers, and ordered according to clinical diagnosis of preeclampsia, gestational hypertension, or healthy pregnancy. RESULTS: The urinary excretion of P-IPG on day 0 was higher in the mothers in all groups (p < 0.05) with higher levels in preeclamptic women (p < 0.01) in the mothers compared to their newborns in the preeclamptic group (p<0.01). The difference persisted at least two days post partum. CONCLUSION: Findings of this study confirm the specificity of the increase in urinary excretion of P-IPG in preeclamptic mothers at day of birth compared to healthy pregnancy and GH, but does not extend to their newborns.

Inositol phosphoglycans and preeclampsia: from bench to bedside.

The metabolic syndrome that occurs in preeclampsia reflects the complex interactions between immunological alterations and the systemic inflammation that have been shown to take place during this complication of human pregnancy. Inositol phosphoglycans play a definite role in the insulin resistance in preeclampsia with a higher production and urinary excretion of this molecule before and during preeclampsia. Recent researches suggest that the feto-placental glucose metabolism in the first and early second trimester is mainly linked to the nonoxidative pathway of glycogen catabolism supporting the pivotal role of the inositol phosphoglycan P-type. In this article we present the results of a case-control study carried out in the first trimester to evaluate the potential of urinary P-IPG release as a early marker of the disease. A single mid-stream sample of maternal urine was collected at 11 weeks of gestation for this single centre retrospective study. Twenty-seven patients out of 331 women recruited (8.1%) went on to develop preeclampsia but no sample attained positivity. Further details about the development of the metabolic syndrome during preeclampsia were retrieved also from other studies to implement our knowledge about the pathophysiology of this syndrome and to identify biochemical aspects that could help in clinical practice.

Urinary inositol phosphoglycan P-type as a marker for prediction of preeclampsia and novel implications for the pathophysiology of this disorder.

OBJECTIVE: Hypertensive disorders represent the most common complications of human pregnancy with substantial impact on fetal and maternal outcomes. Inositol phosphoglycan P-type has recently been identified as a novel marker of preeclampsia, the most severe form of hypertension during pregnancy, with a significant increase in urinary excretion preceding the clinical diagnosis. METHODS: A prospective, longitudinal study was carried out to assess the potential of urinary levels of inositol phosphoglycan P-type as a screening test for preeclampsia. A specific ELISA-based test was used to assess urinary levels of P-IPG. RESULTS: Nine patients out of 93 women recruited (496 urinary samples were collected) went on to develop preeclampsia in a cohort of women with high-risk pregnancies. A cut-off value of urinary inositol phosphoglycan P-type was identified by ROC analysis providing a sensitivity and specificity for the current protocol of 88.9% and 62.7%, respectively. Twenty-three women with healthy pregnancies had sporadic episodes of increased excretion of inositol phosphoglycan P-type during pregnancy that consistently resolved back to normal baseline without development of preeclampsia. There was no correlation of urine levels of inositol phosphoglycan P-type and urine protein and patients with gestational hypertension had normal levels of urine inositol phosphoglycan P-type. CONCLUSIONS: These findings suggest that, given the rapid raise of P-IPG before the onset of the disease, multiple assessments may help at identifying women at risk of developing preeclampsia.

Age-related changes in the response of rat adipocytes to insulin: evidence for a critical role for inositol phosphoglycans and cAMP.

Adipose tissue plays a pivotal role in ageing and longevity; many studies, both human and animal, have focussed on the effects of food limitation. Here we present a new model based on striking differences between two 'normal' inbred strains of albino Wistar rats the Charles River (CR) and Harlan Olac (HO) that have marked differences in age-related accumulation of fat and insulin-stimulated rates of glucose incorporation into lipid in the epididymal fat pads (EFP). The incorporation [U-(14)C]glucose into lipid by adipocytes showed that the CR group had a twofold higher basal rate of lipogenesis and a greater response to insulin in vitro, exceptionally, adipocytes from CR group maintained the high response to insulin to late adulthood while retaining the lower EFP weight/100 g body weight. Inositol phosphoglycan A-type (IPG-A), a putative insulin second messenger, was 3.5-fold higher and cAMP significantly lower per EFP in the CR versus HO groups. Plasma insulin levels were similar and plasma leptin higher in CR versus HO groups. The anomaly of a higher rate of lipogenesis and response to insulin and lower EFP weight in the CR group is interpreted as the resultant effect of a faster turnover of lipid and stimulating effect of leptin in raising fatty acid oxidation by muscle, potentially key to the lower accumulation of visceral fat. The metabolic profile of the CR strain provides a template that could be central to therapies that may lead to the lowering of both adipose and non-adipocyte lipid accumulation in humans in ageing.

The link between insulin resistance and preeclampsia: new perspectives.

In preeclampsia, there is exacerbation of physiological changes associated with pregnancy such as insulin resistance, altered immune responses and inflammatory pathway activation. These exaggerated responses seen in preeclampsia are reminiscent of metabolic syndrome, and also are evident in gestational diabetes mellitus. The link between these phenomena is not clear but novel findings providing some insight have been reported recently. Inositol phosphoglycan P-type (P-IPG) in preeclampsia has been extensively investigated and increased production has been demonstrated. This molecule acts as a second messenger of insulin, enhances the metabolic effects of insulin and is associated with insulin resistance. This review article summarizes current evidence of the role of inositol phosphoglycans in the metabolic syndrome that occurs in preeclampsia, discussed in the light of modifications found in gestational diabetes mellitus and diabetes type 2 in pregnancy in humans and animal models. An increase in urinary release of P-IPG during pregnancy may herald the onset of preeclampsia. Further knowledge about the nature of the metabolic syndrome during preeclampsia and the degree of association between its components will help to inform future research efforts and to identify biochemical markers that could help in clinical practice, for example early markers that will have utility in managing disease progression.

Increased inositol phosphoglycan P-type in the second trimester in pregnant women with type 2 and gestational diabetes mellitus.

A progressive insulin resistant state develops throughout human pregnancy. Inositol phosphoglycan P-type (P-IPG), a second messenger of insulin, was reported to negatively correlate with the degree of insulin resistance in non-pregnant diabetic subjects. Urinary levels of P-IPG were assessed in insulin resistant states during pregnancy such as gestational diabetes mellitus (GDM, n=44) and type 2 diabetes mellitus (type 2 DM, n=25) and in 69 normal pregnant women. Urinary levels of P-IPG were higher in GDM than controls with a positive trend of release throughout normal pregnancy (P<0.01). P-IPG excretion was higher in diabetic (GDM and type 2 DM) than in healthy women in the second trimester (P<0.05). A higher P-IPG urinary excretion occurs during the second trimester in pregnant women with clinically evident insulin resistance with a positive association with poor glycemic control.

Is there a link between insulin resistance and inflammatory activation in preeclampsia?

Preeclampsia is a severe complication of human pregnancy and an insulin resistant state has been demonstrated in this multisystem disorder, although its bases remain unclear. Inositol phosphoglycans P-type belongs to a family of putative insulin mediators and was described to exert many insulin-like effects on lipid and glucose metabolism. A definite association between this molecule and preeclampsia was reported. The systemic inflammatory activation that occurs in preeclampsia as a consequence of the immunological dysfunction can exacerbate placental insulin resistance leading to an over-expression of P-IPG as a counterregulatory mechanism to insulin resistance. Besides, the lipidic form of P-IPG was reported to be similar to endotoxins, and may represent the link between insulin resistance, systemic inflammation and increased angiogenic factors. In this article we propose a new working theory on insulin resistance and preeclampsia.

Reciprocal control of pyruvate dehydrogenase kinase and phosphatase by inositol phosphoglycans. Dynamic state set by "push-pull" system.

Reversible phosphorylation of proteins regulates numerous aspects of cell function, and abnormal phosphorylation is causal in many diseases. Pyruvate dehydrogenase complex (PDC) is central to the regulation of glucose homeostasis. PDC exists in a dynamic equilibrium between de-phospho-(active) and phosphorylated (inactive) forms controlled by pyruvate dehydrogenase phosphatases (PDP1,2) and pyruvate dehydrogenase kinases (PDK1-4). In contrast to the reciprocal regulation of the phospho-/de-phospho cycle of PDC and at the level of expression of the isoforms of PDK and PDP regulated by hormones and diet, there is scant evidence for regulatory factors acting in vivo as reciprocal "on-off" switches. Here we show that the putative insulin mediator inositol phosphoglycan P-type (IPG-P) has a sigmoidal inhibitory action on PDK in addition to its known linear stimulation of PDP. Thus, at critical levels of IPG-P, this sigmoidal/linear model markedly enhances the switchover from the inactive to the active form of PDC, a "push-pull" system that, combined with the developmental and hormonal control of IPG-P, indicates their powerful regulatory function. The release of IPGs from cell membranes by insulin is significant in relation to diabetes. The chelation of IPGs with Mn2+ and Zn2+ suggests a role as "catalytic chelators" coordinating the traffic of metal ions in cells. Synthetic inositol hexosamine analogues are shown here to have a similar linear/sigmoidal reciprocal action on PDC exerting push-pull effects, suggesting their potential for treatment of metabolic disorders, including diabetes.

Release of inositol phosphoglycan P-type by the human placenta following insulin stimulus: a multiple comparison between preeclampsia, intrauterine growth restriction, and gestational hypertension.

OBJECTIVE: Abnormal metabolism of inositol phosphoglycan P-type (P-IPG) has been described in insulin-resistant states. Recently, a definite link between P-IPG and preeclampsia has been reported. P-IPG release after insulin stimulus has been described in the placental tissue of healthy women and a complete absence of P-IPG release has been found in preeclamptic samples, associated with disturbed insulin signaling. This study was undertaken to assess the release of this mediator in intrauterine growth restriction (IUGR) and hypertensive disorders other than preeclampsia. METHODS: Seven women with IUGR, seven with gestational hypertension, 11 with preeclampsia, and 12 controls were recruited for this study. Fresh placental membranes were prepared and incubated with human recombinant insulin. Bioactivity of P-IPG released after insulin stimulus was assessed using a specific bioassay. A multiple comparison between groups was carried out. The study population provided a statistical power of 0.94. RESULTS: P-IPG release was highest and lowest from healthy and preeclamptic samples, respectively (p < 0.01). Specimens from patients with IUGR and gestational hypertension released less P-IPG than did controls (p < 0.05). CONCLUSIONS: Abnormal release of P-IPG from placentas of IUGR and gestational hypertensive mothers seems to confirm an association between these disorders of human pregnancy and insulin resistance.

Altered urinary release of inositol phosphoglycan A-type in women with gestational diabetes mellitus.

BACKGROUND/AIMS: The mechanisms underlying overgrowth of adipose tissue in fetuses of women with gestational diabetes mellitus (GDM) are generally unknown. Inositol phosphoglycan A-type (A-IPG), a putative second messenger of insulin, was reported to regulate lipogenesis in adipose tissue. IPGs have recently been shown to increase during normal pregnancy, in maternal and fetal compartments. METHODS: 48 women with GDM and 23 healthy pregnant women were recruited for this cross-sectional study. Levels of A-IPG were assessed enzymatically in urinary specimens and correlated with clinical parameters. RESULTS: A-IPG urinary release was lower in GDM patients (p < 0.01) and correlated positively with BMI (p < 0.01) and negatively with glycaemic control in the diabetic group (postprandial glycaemia and glycated haemoglobin, p < 0.01) in addition to a nearly significant correlation with birth weight (p = 0.08). Furthermore, a lower A-IPG urinary release was found in diabetic subjects with normal fasting glycaemia compared with those with poor fasting glycaemic control (p < 0.05). CONCLUSIONS: An altered A-IPG urinary excretion occurs in GDM with a negative correlation with poor glycaemic control. Our data suggest an interesting potential role of this molecule in maternal metabolic control during pregnancy and, possibly, in fetal growth.

Preeclampsia, insulin signalling and immunological dysfunction: a fetal, maternal or placental disorder?

An inappropriate glycogen accumulation in preeclamptic placentas was described as secondary to biochemical alterations. Insulin resistance is widely accepted to be associated with preeclampsia, although its basis remain unclear. A family of putative insulin mediators, namely inositol phosphoglycans, were described to exert many insulin-like effects on lipid and glucose metabolism. A definite association between the P-type mediator (P-IPG) and preeclampsia was reported, being increased in placenta, urine, amniotic fluid and cord blood from human preeclamptic pregnancies. A strong link exists between insulin resistance and inflammation. Clear features of insulin resistance and systemic inflammatory activation were described in preeclampsia. It may be a consequence of the immunological dysfunction that occurs in preeclampsia that is temporized during sperm exposure and co-habitation which confuses the maternal immune network to perceive 'danger'. The over-expression of P-IPG during preeclampsia may be a counter-regulatory mechanism to insulin resistance since these molecules mimic insulin action. Besides, the lipidic form of P-IPG was reported to be similar to endotoxins, and may represent the 'danger signa'. We propose here a novel working theory on insulin resistance and preeclampsia.

Inositol phosphoglycan P-type in healthy and preeclamptic pregnancies.

An association between inositol phosphoglycan P-type (P-IPG) and preeclampsia has been demonstrated over recent years. This molecule can mediate many of the metabolic and growth promoting effects of insulin. Dysregulation of the mediator family is associated with insulin resistance. An increased concentration of P-IPG has been reported in preeclamptic placenta, although its precursor (GPI) was undetectable in those placental samples. Insulin administration, that induces P-IPG release in normal human placenta, was shown not to cause production/release of the mediator from preeclamptic placental tissue as a consequence of a disturbed insulin signalling. Amniotic fluid is enriched of this mediator, with further increase during preeclampsia. We have found that the fetus released increasing amounts of P-IPG in the urine between 13 and 18 weeks of gestation, reaching a plateau beyond 20 weeks. Cord blood of infants of preeclamptic mothers showed an increased content of soluble P-IPG compared to controls and to the mother.

Inositol phosphoglycan P-type in preeclampsia: a novel marker?

A state of insulin resistance has been demonstrated in active preeclampsia, and women with clinical evidence of insulin resistance are at higher risk to develop this syndrome during pregnancy. Recently, inositol phosphoglycan P-type, a putative second messenger of insulin action, has been implicated in the pathophysiology of preeclampsia and is increased in the placenta, amniotic fluid, and maternal urine of preeclamptic women compared with normal pregnant women. We report here a case-control study to assess the potential of urinary levels of inositol phosphoglycan P-type as a screening test for preeclampsia. Twenty-seven preeclamptic women and 47 healthy pregnant women were recruited. A polyclonal antibody-based ELISA was developed to detect levels of inositol phosphoglycan P-type in urine. Its content in urinary specimens was found to be 30-fold higher in preeclamptic subjects than control subjects (329.1+/-21.8 versus 9.2+/-1.5; P<0.001), with a higher level in all of the preeclamptic cases. For 6 women who developed preeclampsia, >1 gestational date sample of urine was available, and retrospective analysis showed a significant time-related increase of the urinary level of inositol phosphoglycan P-type