A modular microfluidic platform to enable complex and customisable in vitro models for neuroscience

Disorders of the central nervous system (CNS) represent a global health challenge and an increased understanding of the CNS in both physiological and pathophysiological states is essential to tackle the problem. Modelling CNS conditions is difficult, as traditional in vitro models fail to recapitulate precise microenvironments and animal models of complex disease often have limited translational validity. Microfluidic and organ-on-chip technologies offer an opportunity to develop more physiologically relevant and complex in vitro models of the CNS. They can be developed to allow precise cellular patterning and enhanced experimental capabilities to study neuronal function and dysfunction. To improve ease-of-use of the technology and create new opportunities for novel in vitro studies, we introduce a modular platform consisting of multiple, individual microfluidic units that can be combined in several configurations to create bespoke culture environments. Here, we report proof-of-concept experiments creating complex in vitro models and performing functional analysis of neuronal activity across modular interfaces. This platform technology presents an opportunity to increase our understanding of CNS disease mechanisms and ultimately aid the development of novel therapies.

P–749 Knowledge of women undergoing surgery for endometrioma regarding the impact of the disease and its treatment on ovarian reserve and fertility

Study question

Do women undergoing surgery for endometrioma due to pain, a cyst and/or subfertility understand the impact of the disease and its treatment on ovarian reserve and fertility.

Summary answer

The majority of women treated in a fertility setting are well informed compared to those in a general medical setting. What is known already: Infertility affects 30% to 50% of women with endometriosis. Ovarian endometriomas are reported in 17–44% of infertile women with endometriosis and are typically associated with more severe disease. Endometriomas are associated with diminished ovarian reserve, due to the endometrioma per se or due to surgical interventions required to treat and excise the disease. ESHRE guidelines recommend that women should be informed pre-operatively of the potential reduction in ovarian reserve associated with surgery and that ovarian reserve tests should be performed when future fertility is a concern.

Study design, size, duration

In conjunction with our histopathology colleagues we identified a cohort of women with a histological diagnosis of one or more ovarian endometriomas who underwent surgery in our unit between 2010 and 2019. We developed a scoping questionnaire, targeted at women currently over the age of 40, who had previously undergone surgery for endometrioma under the age of 35. Patients were contacted by telephone and consent obtained to send an email with a survey link.

Participants/materials, setting, methods

We identified 47 women who had a histological diagnosis of endometrioma. Of these, 30 were contactable by telephone, of whom 29 consented to being sent information regarding the study and a link to the questionnaire. 21 women completed the survey. Respondents were divided into 2 groups for analysis. Group 1 cited ‘fertility’ or ‘both pain and fertility’ as an indication for their surgery while group 2 had ‘pain’ or ‘ovarian cysts’ but no fertility concerns. Main results and the role of chance: The majority (62%) of patients were diagnosed with endometriosis while aged 25–34. The indication for surgery was evenly divided between pain (32%), fertility (37%) and ovarian cysts (37%). 60% of women reported having endometriomas diagnosed preoperatively. Striking differences were noted between groups 1 and 2. Of the women who cited ‘fertility’ or ‘both pain and fertility’ (n = 9) as an indication for their surgery, 78% (n = 7) reported being aware of any possible negative impact of endometriosis on their fertility, with 78% also being aware of the possible negative impact of surgery for endometriosis on their fertility. This compared to only 36% (n = 4) and 27% (n = 3) respectively in Group 2. In group 1, 56% (n = 5) remembered having an AMH level checked pre operatively while 78% (n = 7) also had an ultrasound pre-operatively.

In contrast, only 33% (n = 3) of Group 2 remember having an AMH level checked pre operatively though 64% (n = 7) had an ultrasound pre-operatively.

Of those whose surgery was performed by a fertility specialist, 75% (n = 6) reported being aware of the impact of endometriosis and also the impact of surgery on ovarian reserve, compared to 44% (n = 4) of those who surgery was performed by a non-fertility specialist.

Limitations, reasons for caution

This is a retrospective study and the numbers are small. We were only able to identify women with an endometrioma via pathology records, so those with no excision of disease (eg those who had ablation of an endometrioma) were excluded from this analysis.

Wider implications of the findings: This suggests the majority of patients treated in a fertility setting are counselled regarding the benefit of surgery but also the risk to ovarian reserve. This is not the case in other settings. It is time to disseminate guidelines such as those produced by ESHRE to our general gynaecology colleagues.

Trial registration number

Not applicable

Dysregulation of the interleukin-17A pathway in endometrial tissue from women with unexplained infertility affects pregnancy outcome following assisted reproductive treatment

STUDY QUESTION

Which transcriptomic alterations in mid-luteal endometrial scratch biopsies, taken prior to the assisted reproductive treatment (ART) treatment cycle are associated with unsuccessful pregnancy?

SUMMARY ANSWER

Dysregulated interleukin-17 (IL-17) pathway components are demonstrated in women who fail to become pregnant after ART.

WHAT IS KNOWN ALREADY

Implantation failure is now recognised as a critical factor in unexplained infertility and may be an important component of failed ART.

STUDY DESIGN, SIZE, DURATION

Using a prospective longitudinal study design, 29 nulliparous women with unexplained infertility undergoing ART were recruited between October 2016 and February 2018. Mid-luteal stage endometrium and matched serum samples were collected, and patients underwent a single embryo transfer in the subsequent cycle. RNA-seq analysis of endometrial biopsies was performed on the discovery cohort (n = 20).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Gene set enrichment analysis of the differentially expressed genes (DEGs) was performed. Endometrium and serum were then prepared for IL-17A analysis by ELISA.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 204 differentially expressed protein-coding genes identified in tissue from women who became pregnant (n = 9) compared with tissue from women who failed to become pregnant (n = 11) (false discovery rate; P < 0.05). Of the 204 DEGs, 166 were decreased while 38 were increased in the pregnant compared to the non-pregnant groups. Gene set enrichment analysis of the DEGs identified an over-representation of IL-17 and Pl3K-Akt signalling pathways. All the DEGs within the IL-17 signalling pathway (MMP3, MMP1, IL1β, LCN2, S100A9 and FOSL1) demonstrated decreased expression in the pregnant group. Serum IL-17 protein levels were increased in the non-pregnant discovery cohort (n = 11) and these findings were confirmed a validation cohort (n = 9).

LIMITATIONS, REASONS FOR CAUTION

Limitations of our study include the cohort size and the lack of aneuploidy data for the embryos; however, all embryos transferred were single good or top-quality blastocysts.

WIDER IMPLICATIONS OF THE FINDINGS

These findings demonstrate dysregulated IL-17 pathway components in women who fail to become pregnant after ART. Elevated serum levels of the pro-inflammatory cytokine IL-17 may predict failure of ART in women with unexplained infertility. Future trials of anti-IL-17 therapies in this cohort warrant further investigation.

STUDY FUNDING/COMPETING INTEREST(S)

Funding from the UCD Wellcome Institutional Strategic Support Fund, which was financed jointly by University College Dublin and the SFI-HRB-Wellcome Biomedical Research Partnership (ref 204844/Z/16/Z), is acknowledged. The authors have no competing interests.

TRIAL REGISTRATION NUMBER

NA.

Intravesical chondroitin sulphate for interstitial cystitis/painful bladder syndrome

INTRODUCTION

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic inflammatory condition of the bladder. Bladder instillation is one avenue of treatment but evidence for its effectiveness is limited. Chondroitin sulphate solution 2.0% (Urocyst) is a glycosaminoglycan (GAG) replenishment therapy instilled for patients with IC/PBS. We assessed its effectiveness for treating IC/PBS in Northern Ireland.

METHODS

Patients with IC/PBS were assessed with the O'Leary-Sant interstitial cystitis index score and global response assessment questionnaire prior to commencing treatment. Assessment with these questionnaires was performed after 6 treatments (10 weeks) and again after 10 treatments (24 weeks). Assessment end points were pain, urgency, symptom score and problem score.

RESULTS

Data was collected on 10 patients, 9 female and 1 male. 6 patients had failed RIMSO-50 dimethyl sulphoxide (DMSO) 50% treatment prior. At baseline the mean pain score was 6.6, urgency score 7.00, symptom score 13.5 and problem score 12.5. After 24 weeks the mean pain score fell to 2.0, urgency score to 1.80, symptom score to 6.89 and problem score to 5.67. At 10 weeks the global response to treatment was 100%. Nocturia was the first symptom to improve with urgency and pain following. No side effects were noted during instillation and all patients tolerated the treatments.

CONCLUSION

IC/PBS is a difficult disease to treat. It requires a multimodal approach. We found that intravesical chondroitin sulphate reduced pain, urgency and O'Leary-Sant symptom and problem scores in patients with IC/PBS. All patients tolerated the treatment and no side effects were reported.

Neonatal referrals to the coroner service: a short survey on current practice

In Ireland, coroners are required by law to ascertain the details of potentially unexplained deaths. The Coroner's Acts (1962 and 2005) detail deaths which must be notified to the coroner. We surveyed current practice regarding the notification of the Coroner Service following neonatal deaths by telephone interview of senior clinical nurse managers of paediatric units with neonatal inpatients. Five of 21 units (23.8%) reported that all neonatal deaths would prompt contact with the Coroner Service, with four more units (19%) reporting that unexpected neonatal deaths would be referred. Nine units (42.9%) reported that referral was at the discretion of the consultant involved while three units (14.3%) do not refer neonatal deaths to the coroner.

Placental pathology associated with small for gestational age infants

Infants with intrauterine growth restriction (IUGR) are at an increased risk of perinatal disease, including death. Many, but not all small for gestational age infants (SGA) have IUGR. Placental disease is an important cause of IUGR, and gross and microscopic examination is critical in explaining such cases. Reports of placentas from infants with a birth weight < 2SD from the mean (approx 3rd centile) born between Jan 2004-Dec 2011 were evaluated. The principal pathology was determined in each case. Where two or more pathologic findings were present, they were ranked as principal and co-existing in terms of severity. There were 69,493 deliveries over the study period. 461 SGA cases were identified. No placenta was available in 44 cases, and 21 cases of known anomalies were excluded, leaving a study group of 396 cases. Pathology potentially causing or contributing to SGA and/or IUGR was identified in 84.1% of cases. Significant co-existing pathology was seen in 88 cases (22%). Placental examination provides key information in understanding abnormal fetal growth.

Reversible inhibition of the glycine transporter GlyT2 circumvents acute toxicity while preserving efficacy in the treatment of pain

BACKGROUND AND PURPOSE

Available medications for chronic pain provide only partial relief and often cause unacceptable side effects. There is therefore a need for novel molecular targets to develop new therapeutics with improved efficacy and tolerability. Despite encouraging efficacy data in rodents with inhibitors of the neuronal glycine transporter-2 (GlyT2), there are also some reports of toxicity and their development was discontinued.

EXPERIMENTAL APPROACH

In order to clarify the possibility of targeting GlyT2 for the treatment of pain, we have used an integrated approach comprising in vitro pharmacology, selectivity, bioavailability, in vivo efficacy and safety assessment to analyse the properties and efficacy of ALX-1393 and Org-25543, the two published GlyT2 inhibitors from which in vivo data are available.

KEY RESULTS

We report that these compounds have a different set of undesirable properties that limit their usefulness as pharmacological tools. Importantly, we discover that inhibitors of GlyT2 can exert an apparent reversible or irreversible inhibition of the transporter and describe a new class of reversible GlyT2 inhibitors that preserves efficacy while avoiding acute toxicity.

CONCLUSIONS AND IMPLICATIONS

Our pharmacological comparison of two closely related GlyT2 inhibitors with different modes of inhibition provides important insights into their safety and efficacy profiles, uncovering that in the presence of a GlyT2 mechanism-based toxicity, reversible inhibitors might allow a tolerable balance between efficacy and toxicity. These findings shed light into the drawbacks associated with the early GlyT2 inhibitors and describe a new mechanism that might serve as the starting point for new drug development.

Novel placental ultrasound assessment: potential role in pre-gestational diabetic pregnancy

OBJECTIVES

Management of women with pre-gestational diabetes continues to be challenging for clinicians. This study aims to determine if 3D power Doppler (3DPD) analysis of placental volume and flow, and calculation of placental calcification using a novel software method, differ between pregnancies with type 1 or type 2 diabetes and normal controls, and if there is a relationship between these ultrasound placental parameters and clinical measures in diabetics.

METHODS

This was a prospective cohort study of 50 women with diabetes and 250 controls (12-40 weeks gestation). 3DPD ultrasound was used to evaluate placental volume, vascularisation index (VI), flow index (FI) and vascularisation-flow index (VFI). Placental calcification was calculated by computer analysis. Results in diabetics were compared with control values, and correlated with early pregnancy HbA1c, Doppler results and placental histology.

RESULTS

Placental calcification and volume increased with advancing gestation in pre-gestational diabetic placentae. Volume was also found to be significantly higher than in normal placentae. VI and VFI were significantly lower in diabetic pregnancies between 35 and 40 weeks gestation. A strong relationship was seen between a larger placental volume and both increasing umbilical artery pulsatility index and decreasing middle cerebral artery pulsatility index. FI was significantly lower in cases which had a booking HbA1c level ≥6.5%. Ultrasound assessed placental calcification was reduced with a histology finding of delayed villous maturation. No other correlation with placental histology was found.

CONCLUSIONS

This study shows a potential role for 3D placental evaluation, and computer analysis of calcification, in monitoring pre-gestational diabetic pregnancies.

Collecting Duct Carcinoma of the kidney: A case report with variable immunohistochemistry

BACKGROUND

Collecting duct carcinoma of the kidney is a rare tumour with distinctive clinical and histopathological features. Management of this malignancy remains a challenge because of advanced stage at presentation and aggressive clinical course.

AIMS

We describe a case of Collecting Duct Carcinoma with variable immunohistochemistry and review the pathology and management.

RESULTS

Our patient died shortly after commencing systemic chemotherapy.

CONCLUSION

Advances in immunohistochemistry have aided in diagnosis of this tumour. Early detection and nephrectomy offer the best chance of cure. Newer chemotherapeutic regimens may improve survival in more advanced disease.

Independent predictors of breast malignancy in screen-detected microcalcifications: biopsy results in 2545 cases

Background:

Mammographic microcalcifications are associated with many benign lesions, ductal carcinoma in situ (DCIS) and invasive cancer. Careful assessment criteria are required to minimise benign biopsies while optimising cancer diagnosis. We wished to evaluate the assessment outcomes of microcalcifications biopsied in the setting of population-based breast cancer screening.

Methods:

Between January 1992 and December 2007, cases biopsied in which microcalcifications were the only imaging abnormality were included. Patient demographics, imaging features and final histology were subjected to statistical analysis to determine independent predictors of malignancy.

Results:

In all, 2545 lesions, with a mean diameter of 21.8 mm (s.d. 23.8 mm) and observed in patients with a mean age of 57.7 years (s.d. 8.4 years), were included. Using the grading system adopted by the RANZCR, the grade was 3 in 47.7% 4 in 28.3% and 5 in 24.0%. After assessment, 1220 lesions (47.9%) were malignant (809 DCIS only, 411 DCIS with invasive cancer) and 1325 (52.1%) were non-malignant, including 122 (4.8%) premalignant lesions (lobular carcinoma in situ, atypical lobular hyperplasia and atypical ductal hyperplasia). Only 30.9% of the DCIS was of low grade.

Mammographic extent of microcalcifications >15 mm, imaging grade, their pattern of distribution, presence of a palpable mass and detection after the first screening episode showed significant univariate associations with malignancy. On multivariate modeling imaging grade, mammographic extent of microcalcifications >15 mm, palpable mass and screening episode were retained as independent predictors of malignancy. Radiological grade had the largest effect with lesions of grade 4 and 5 being 2.2 and 3.3 times more likely to be malignant, respectively, than grade 3 lesions.

Conclusion:

The radiological grading scheme used throughout Australia and parts of Europe is validated as a useful system of stratifying microcalcifications into groups with significantly different risks of malignancy. Biopsy assessment of appropriately selected microcalcifications is an effective method of detecting invasive breast cancer and DCIS, particularly of non-low-grade subtypes.

PEA3/ETV4-related transcription factors coupled with active ERK signalling are associated with poor prognosis in gastric adenocarcinoma

Background:

Transcription factors often play important roles in tumourigenesis. Members of the PEA3 subfamily of ETS-domain transcription factors fulfil such a role and have been associated with tumour metastasis in several different cancers. Moreover, the activity of the PEA3 subfamily transcription factors is potentiated by Ras-ERK pathway signalling, which is itself often deregulated in tumour cells.

Methods:

Immunohistochemical patterns of PEA3 expression and active ERK signalling were analysed and mRNA expression levels of PEA3, ER81, MMP-1 and MMP-7 were determined in gastric adenocarcinoma samples.

Results:

Here, we have studied the expression of the PEA3 subfamily members PEA3/ETV4 and ER81/ETV1 in gastric adenocarcinomas. PEA3 is upregulated at the protein level in gastric adenocarcinomas and both PEA3/ETV4 and ER81/ETV1 are upregulated at the mRNA level in gastric adenocarcinoma tissues. This increased expression correlates with the expression of a target gene associated with metastasis, MMP-1. Enhanced ERK signalling is also more prevalent in late-stage gastric adenocarcinomas, and the co-association of ERK signalling and PEA3 expression also occurs in late-stage gastric adenocarcinomas. Furthermore, the co-association of ERK signalling and PEA3 expression correlates with decreased survival rates.

Conclusions:

This study shows that members of the PEA3 subfamily of transcription factors are upregulated in gastric adenocarcinomas and that the simultaneous upregulation of PEA3 expression and ERK pathway signalling is indicative of late-stage disease and a poor survival prognosis.

[High volume hemofiltration in septic shock]

Severe sepsis and septic shock are conditions associated with high morbidity and mortality. The disproportionate release of pro-inflammatory and anti-inflammatory mediators caused by the septic insult is the promoter of multiple organ dysfunction. Conventional hemodialysis, hemofiltration or a combination of both can be a good option to replace the deteriorating renal function in critically ill patients by the removal of nitrogen compounds (small molecules). However, this "renal dose" is insufficient for the removal of inflammatory mediators (medium molecules), and therefore contributes little to the cardiovascular stabilization of patients with septic shock. In this setting, a higher dose of ultrafiltration (> 50 ml/kg/h) or "septic dose" may be needed. In this review article, we have analyzed the clinical and pathophysiological rationale for the use of high volume hemofiltration in patients with septic shock.

Assessment of 1183 screen-detected, category 3B, circumscribed masses by cytology and core biopsy with long-term follow up data

Discrete masses are commonly detected during mammographic screening and most such lesions are benign. For lesions without pathognomonically benign imaging features that are still regarded likely to be non-malignant (Tabar grade 3) reliable biopsy results would be a clinically useful alternative to mammographic surveillance. Appropriate institutional guidelines for ethical research were followed. Between Jan 1996--Dec 2005 grade 3B discrete masses detected in the setting of a large, population based, breast cancer screening programme are included. Patient demographics, fine needle aspiration biopsy (FNAB), core and surgical biopsy results are tabulated. The final pathology of excised lesions was obtained. Information regarding interval cancers was obtained from the State Cancer Registry records and also through long term follow-up of clients in subsequent rounds of screening. A total of 1183 lesions, mean diameter of 13.3 mm (+/-8.3 mm) and mean client age of 55.1 years (+/-8.8 years) are included. After diagnostic work up, 98 lesions (8.3%) were malignant, 1083 were non-malignant and a final histologic diagnosis was not established in two lesions. In the 27 months after assessment, no interval cancers were attributable to these lesions and during a mean follow up of 54.5 months, available in 84.9% of eligible women, only one cancer has developed in the same quadrant as the original lesion, although the two processes are believed to be unrelated. FNAB performed in 1149 cases was definitive in 80.5% cases (882 benign, 43 malignant) with a negative predictive value (NPV) of 99.8% (880 of 882) and a positive predictive value (PPV) of 95.2% (40 of 42, both intraductal papillomas). Core biopsy was performed in 178 lesions, mostly for indefinite cytology. Core biopsy was definitive in 79.8% cases (57% benign 22% malignant) with a PPV of 100% and NPV of 99.0%. In experienced hands FNAB is an accurate first line diagnostic modality for the assessment of 3B screen-detected discrete masses, providing definitive results in 80.5% of cases. When used as a second line modality, core biopsy had a similarly high rate of definitive diagnosis at 79.8%. The stepwise approach to the use of FNAB and core biopsy would reduce substantially the proportion of cases requiring surgical diagnostic biopsy. Given the low probability of malignancy and the imperative to limit the morbidity associated with cancer screening, the demonstration of the reliability of FNAB as a minimally invasive but highly accurate test for this particular subset of screen-detected lesions has significant clinical utility.

Extra-corporeal shock wave lithotripsy (ESWL) versus ureteroscopic management for ureteric calculi

BACKGROUND

Ureteral stones frequently cause renal colic and if left untreated can cause obstructive uropathy. Extracorporeal Shock Wave Lithotripsy (ESWL) and ureteroscopy, with or without intracorporeal lithotripsy, are the two most commonly offered interventional procedures in these patients. ESWL treatment is less invasive but has some limitations such as a high retreatment rate and lack of availability in many centres. Advances in ureteroscopy over the past decade have increased the success rate and reduced complication rates.

OBJECTIVES

To examine evidence from randomised controlled trials (RCTs) on the outcomes of ESWL or ureteroscopy in the treatment of ureteric calculi.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library Issue 2, 2006), MEDLINE (1966 - March 2006), EMBASE (1980 - March 2006), reference lists of articles and abstracts from conference proceedings without language restriction.

SELECTION CRITERIA

RCTs comparing ESWL with ureteroscopic retrieval of ureteric stones were included. Participants were adults with ureteric stones requiring intervention. Published and unpublished sources were considered.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes or weighted mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Six RCTs (833 patients) were included. The stone-free rates were lower in the ESWL group (RR 0.84 95% CI 0.73 to 0.96). The retreatment rates were lower but not significant in the ureteroscopy group (RR 3.34 95% CI 0.82 to 13.62). The rate of complications was lower in the ESWL group (RR 0.48 95% CI 0.26 to 0.91). Length of hospital stay was less for ESWL treatment (MD -2.10 95% CI -2.55 to -1.64).

AUTHORS' CONCLUSIONS

Ureteroscopic removal of ureteral stones achieves a higher stone-free state but with a higher complication rate and a longer hospital stay.

Pancreatic abscess due to Aeromonas hydrophila

Aeromonas hydrophila is an uncommon cause of deep-seated infection in man. We present what we believe to be the first reported case of a pancreatic abscess due to A. hydrophila. The outcome of this case attests to the potentially lethal nature of infection that can occur with this organism.

Acromegaly secondary to growth hormone releasing hormone secretion

BACKGROUND

Acromegaly secondary to growth hormone releasing hormone (GHRH) secretion is exceptionally rare.

AIM

To report a case of acromegaly diagnosed in 1984 and assumed to be pituitary in origin. Sixteen years later, the cause was found to be a GHRH secreting neuroendocrine pancreatic tumour.

METHOD

A case report.

CONCLUSION

Although ectopic GHRH production is very rare, endocrinologists should be aware of this possibility in acromegaly patients if a pituitary tumour was not detected using pituitary imaging.

Contemporary management of renal calculus disease

The management of renal calculus disease has changed. Non-invasive and minimally invasive techniques of stone disintegration and removal have replaced open stone surgery in managing this condition. In this article we discuss the investigation and management of patients with renal stone disease as currently performed in specialist stone centres.

[Refractory arterial hypertension and the use of anticonvulsant drugs. Case report]

Resistant arterial hypertension is uncommon when there is good compliance to antihypertensive therapy and secondary causes have been ruled out. We report a 41 years old male that suffered hypertensive encephalopathy and received prophylactic anticonvulsant therapy showing progressive raise of arterial pressure levels. Renovascular hypertension, aldosteronism and pheochromocytoma were discarded and, in spite of combined use of antihypertensive drugs, he did not achieve normal blood pressure. When phenytoin was discontinued, blood pressure temporarily normalized. Carbamazepine was started and blood pressure raised again. It fell when this medication was discontinued. Antiepileptic agents could induce drug metabolizing system and thus reduce the effects of antihypertensive medications.

Inflammation, not hyperhomocysteinemia, is related to oxidative stress and hemostatic and endothelial dysfunction in uremia

BACKGROUND

Several cardiovascular risk factors are present in patients with chronic renal failure (CRF), among which are systemic inflammation and hyperhomocysteinemia. Increased oxidative stress, endothelial activation/dysfunction, and coagulation activation are considered integral components of the inflammatory response, but have also been proposed as mediators of plasma homocysteine (tHcy)-induced cell damage. Using correlation analysis, we assessed the relative contributions of inflammation and hyperhomocysteinemia in the abnormal oxidative stress, endothelial activation/dysfunction, and hemostasis activation in patients with CRF.

METHODS

The relationships of inflammatory proteins and tHcy with plasma markers of these processes were studied in 64 patients with CRF (serum creatinine 526 +/- 319 micromol/L) on conservative treatment, comparing the results with healthy controls (N = 15 to 40, depending on the measured variable) of similar sex and age.

RESULTS

Patients had significant increases in inflammatory cytokines (TNF-alpha and IL-8) and acute-phase proteins (C-reactive protein, fibrinogen and alpha1-antitrypsin). tHcy was increased in 87.5% of patients (mean = 27.1 micromol/L, range 6.5 to 118). Patients had significant increases in (1) indices of oxidative stress: TBARS (thiobarbituric acid-reactive species), a marker of lipid peroxidation and AOPP (advanced oxidation protein products), a marker of protein oxidation; (2) endothelial cell markers such as von Willebrand factor (vWF:Ag), soluble ICAM-1 and soluble thrombomodulin (sTM); (3) markers of intravascular thrombin generation: thrombin-antithrombin complexes (TAT) and prothrombin fragment F(1+2) (PF(1+2)); and (4) indices of activation of fibrinolysis: plasmin-antiplasmin complexes (PAP), fibrin degradation products (FnDP) and fibrinogen degradation products (FgDP). tHcy was significantly correlated with plasma creatinine (r = 0.29, P < 0.018) and with serum folate (r = -0.38, P < 0.002). However, no significant correlations were observed between tHcy and TBARS, AOPP, vWF:Ag, sICAM-1, sTM, TAT, F(1+2), sTF, PAP, FnDP, and FgDP. Conversely, acute-phase proteins showed significant, positive correlations with most markers of oxidative stress, endothelial dysfunction and hemostatic activation.

CONCLUSIONS

Systemic inflammation, which is closely associated with augmented oxidative stress, endothelial cell dysfunction and hemostatic activation, emerges as a major cardiovascular risk factor in CRF. tHcy is unrelated to these events. Thus, alternative mechanisms through which hyperhomocysteinemia could predispose to vascular lesion and thrombotic events in CRF needs to be investigated.

Increased activation of protein C, but lower plasma levels of free, activated protein C in uraemic patients: relationship with systemic inflammation and haemostatic activation

Chronic renal failure (CRF) courses with both systemic inflammatory reaction and haemostatic activation. We explored the relationship of these processes with plasma levels of free, activated protein C (APC) and complexes of APC with its inhibitors in patients with CRF under conservative treatment. Plasma concentrations of inflammatory cytokines [tumour necrosis factor alpha (TNFalpha) and interleukin 8], acute-phase proteins (C-reactive protein, fibrinogen, alpha1-anti-trypsin and von Willebrand factor), and markers of haemostatic activation (thrombin-anti-thrombin complexes, plasmin-anti-plasmin complexes, and fibrin and fibrinogen degradation products) were higher in patients than in controls. Inflammatory and haemostatic markers were significantly and positively correlated. Total plasma APC and APC:alpha1-anti-trypsin (alpha1AT) complexes were 44% and 75% higher in patients than in controls (P = 0.0001), whereas free APC was 20% lower (P < 0.015). No significant difference was observed in APC:protein C inhibitor (PCI) complexes between both groups. The free/total APC ratio was significantly lower in patients than in controls (P < 0.0001). Total plasma APC and APC:alpha1AT were positively correlated with activation markers of haemostasis and acute-phase proteins, whereas free APC was inversely correlated with plasma levels of creatinine, acute-phase proteins and fibrin degradation products (FnDP). Systemic inflammation and activation of haemostasis are interrelated processes in CRF. APC generation was increased in response to elevated thrombin production, but the inflammatory reaction, associated with increased synthesis of alpha1AT, reduced its anticoagulant effect. Lower free plasma APC in CRF may be pathogenically associated with atherothrombosis, a major cause of death in this disease.

Renal concentrating defect in mice lacking group IV cytosolic phospholipase A(2)

Eicosanoids regulate various cellular functions that are important in physiological and pathophysiological processes. Arachidonic acid is released from membranes by phospholipase A(2) (PLA(2)) activity. Activated macrophages derived from mice lacking the 85-kDa group IV cytosolic PLA(2) (cPLA(2)) have a markedly reduced release of prostaglandin E(2) and leukotrienes B(4) and C(4). Under basal conditions and after furosemide, urinary prostaglandin E(2) excretion is reduced in cPLA(2)-knockout (cPLA(2)(-/-)) mice. Serum creatinine, Na(+), K(+), and Ca(2+) concentrations, glomerular filtration rate, and fractional excretion of Na(+) and K(+) are not different in cPLA(2)(-/-) and cPLA(2)(+/+) mice. Maximal urinary concentration is lower in 48-h water-deprived cPLA(2)(-/-) mice compared with cPLA(2)(+/+) animals (1,934 +/- 324 vs. 3,541 +/- 251 mmol/kgH(2)O). Plasma osmolality is higher (337 +/- 5 vs. 319 +/- 3 mmol/kgH(2)O) in cPLA(2)(-/-) mice that lose a greater percentage of their body weight (20 +/- 2 vs. 13 +/- 1%) compared with cPLA(2)(+/+) mice after water deprivation. Vasopressin does not correct the concentrating defect. There is progressive reduction in urinary osmolality with age in cPLA(2)(-/-) mice. Membrane-associated aquaporin-1 (AQP1) expression, identified by immunocytochemical techniques, is reduced markedly in proximal tubules of older cPLA(2)(-/-) animals but is normal in thin descending limbs. However, Western blot analysis of kidney cortical samples revealed an equivalent AQP1 signal intensity in cPLA(2)(+/+) and cPLA(2)(-/-) animals. Young cPLA(2)(-/-) mice have normal proximal tubule AQP1 staining. Collecting duct AQP2, -3, and -4 were normally expressed in the cPLA(2)(-/-) mice. Thus mice lacking cPLA(2) develop an age-related defect in renal concentration that may be related to abnormal trafficking and/or folding of AQP1 in the proximal tubule, implicating cPLA(2) in these processes.

Ischemia-reperfusion injury after relief of ureteral obstruction: an animal study

BACKGROUND AND PURPOSE

The complex series of pathophysiologic alterations associated with obstruction nephropathy includes renal ischemia. Free-radical production follows relief of obstruction. We sought to determine whether free radicals caused additional reduction in blood flow after relief of obstruction.

MATERIALS AND METHODS

In White-Landrace pigs, the left ureter was divided 6 cm distal to the ureteropelvic junction, and a nephrostomy tube was passed into the renal pelvis and exteriorized. A catheter was placed in the renal vein and exteriorized. Mean renal blood flow was measured before manipulation and during and after 6 hours of obstruction in animals receiving (N = 7) or not receiving (N = 7) allopurinol. The control groups were not subjected to ureteral obstruction and received (N = 7) or did not receive (N = 7) allopurinol. Free radicals in venous blood were measured by the Fox-1 assay for lipid peroxidation.

RESULTS

After obstruction, renal blood flow declined significantly by the sixth hour (-28.73% +/- 1.81). The increase after relief of obstruction was only temporary, and by the third hour, the blood flow was again reduced (-20.14% +/- 2.67). Free radical production was significantly increased, with a peak of +24.63% being found 60 minutes after relief of obstruction. Allopurinol prevented free radical production after relief of obstruction and was associated with a return of blood flow to baseline values.

CONCLUSION

Free radicals contribute to renal blood flow reduction after relief of ureteral obstruction. Functional impairment may be preventable by free radical blockade, but further studies are required to confirm this hypothesis.

A novel K+ channel expressed in carrot roots with a low susceptibility toward metal ions

Kdc1 is a novel K+-channel gene cloned from carrot roots, and which is also present in cultured carrot cells. We investigated the characteristics of the ionic current elicited in Xenopus oocytes coinjected with KDC1 (K+-Daucus carota 1) and KAT1 (from Arabidopsis thaliana) RNA. Expressed heteromeric channels displayed inward-rectifying potassium currents whose kinetics, voltage characteristics, and inhibition by metal ions depended on KDC1:KAT1 ratios. At low KDC1:KAT1 ratios, Zn2+ inhibition of heteromeric K+ current was less pronounced compared to homomeric KAT1 channels, while at higher KDC1:KAT1 ratios, the addition of Zn2+ even produced an increase in current. Under the same conditions, the Ni2+ inhibition of the current was also reduced, but no current increase was observed. These effects might be explained by the unusual amino acid composition of the KDC1 protein in terms of histidine residues that are absent in the pore region, but abundant (four per subunit) in the proximity of the pore entrance. Channels like KDC1 could be at least partially responsible for the higher resistance of carrot cells in the presence of metals.

KDC1, a novel carrot root hair K+ channel. Cloning, characterization, and expression in mammalian cells

Potassium is an essential nutrient which plays an important role in many aspects of plant growth and development. Plants have developed a number of highly specific mechanisms to take up potassium from the soil; these include the expression of K(+) transporters and potassium channels in root cells. Despite the fact that root epidermal and hair cells are in direct contact with the soil, the role of these tissues in K(+) uptake is not well understood. Here we report the molecular cloning and functional characterization of a novel potassium channel KDC1 which forms part of a new subfamily of plant K(in) channels. Kdc1 was isolated from carrot root RNA and in situ hybridization experiments show Kdc1 to be highly expressed in root hair cells. Expressing the KDC1 protein in Chinese hamster ovary cells identified it as a voltage and pH-dependent inwardly rectifying potassium channel. An electrophysiological analysis of carrot root hair protoplasts confirmed the biophysical properties of the Kdc1 gene product (KDC1) in the heterologous expression system. KDC1 thus represents a major K(+) uptake channel in carrot root hair cells.

A study of mild fetal pyelectasia - outcome and proposed strategy of management

Mild fetal pyelectasia, defined as a renal pelvic anteroposterior (AP) diameter of 4-10 mm, has become a frequent finding on fetal ultrasonography. The natural history of such dilatation is unclear, resulting in confusion as to appropriate postnatal investigation and management. The aim of this study was to examine the urinary tract outcome of a series of infants with mild fetal pyelectasia demonstrated on routine morphology ultrasonogram between 16 and 21 weeks' gestation. Of the 37 cases identified, 13 (35%) went on to require medical or surgical intervention for significant urinary tract anomalies. These anomalies included pelvi-ureteric junction obstruction, dysplastic kidney, vesicoureteric reflux and posterior urethral valves. On initial scan all cases had an AP diameter of 4-8 mm and did not predict those infants who would go on to require intervention. An AP diameter of greater than 7 mm on repeat scans performed after 27 weeks' gestation had a positive predictive value of 0.92 and a negative predictive value of 0.76 for significant urinary tract anomaly requiring intervention. The specificity was 0. 94 and sensitivity 0.70. A protocol of one repeat antenatal ultrasound at 28-34 weeks' gestation would be able to identify those infants who would require postnatal investigation, using a measurement of >/=7 mm. The fetus with a normal repeat ultrasound would not require postnatal follow-up.

Current advances in shock wave lithotripsy

The introduction of shock wave lithotripsy into clinical practice revolutionized the management of urinary tract stone disease. As experience has been gained with its use, however, the limitations and adverse effects associated with it have been recognized.

Endothelial cell markers in chronic uremia: relationship with hemostatic defects and severity of renal failure

Plasma von Willebrand factor antigen, soluble thrombomodulin, and tissue factor were increased in 31 patients with severe chronic renal failure (creatinine clearance <20 ml/min) under conservative treatment, whereas plasminogen activator inhibitor antigen did not differ significantly from healthy controls. No correlation among plasma levels of these proteins was found. Three patterns of relationship between endothelial cell markers and hemostatic defects were identified: 1) Plasma thrombomodulin, a marker of endothelium damage, was found an independent predictor of bleeding time and platelet aggregation, and secretion defects, and was also related to the severity of renal failure; 2) von Willebrand factor antigen, an index of endothelial cell activation and secretion, was significantly correlated with intravascular markers of thrombin and plasmin generation and with platelet adenosine triphosphate content, but not with plasma creatinine levels; and 3) tissue factor and plasminogen activator inhibitor antigen levels were not statistically correlated with the diverse hemostatic defects. Activation of coagulation and fibrinolysis, secondary to endothelial cell activation, appearing early during the evolution of chronic renal failure, is pathogenically related to the platelet dysfunction, and probably to development of atherosclerosis and thrombotic events in this disease. The progression of chronic renal failure, through endothelial cell damage, would lead to aggravation of the platelet functional defect potentiating the hemorrhagic risk.