Levels of type XVII collagen (BP180) ectodomain are elevated in circulation from patients with multiple cancer types and is prognostic for patients with metastatic colorectal cancer

BACKGROUND

Collagens are the major components of the extracellular matrix (ECM) and are known to contribute to tumor progression and metastasis. There are 28 different types of collagens each with unique functions in maintaining tissue structure and function. Type XVII collagen (BP180) is a type II transmembrane protein that provides stable adhesion between epithelial cells and the underlying basement membrane. Aberrant expression and ectodomain shedding of type XVII collagen have been associated with epithelial damage, tumor invasiveness, and metastasis in multiple tumor types and may consequently be used as a potential (non-invasive) biomarker in cancer and treatment target.

METHOD

An ELISA targeting the type XVII collagen ectodomain (PRO-C17) was developed for use in serum. PRO-C17 was measured in a cohort of patients with 11 different cancer types (n = 214) and compared to healthy controls (n = 23) (cohort 1). Based on the findings from cohort 1, PRO-C17 and its association with survival was explored in patients with metastatic colorectal cancer (mCRC) treated with bevacizumab in combination with chemotherapy (n = 212) (cohort 2).

RESULTS

PRO-C17 was robust and specific towards the ectodomain of type XVII collagen. In cohort 1, PRO-C17 levels were elevated (p < 0.05) in serum from patients with CRC, kidney, ovarian, bladder, breast, and head and neck cancer compared to healthy controls. PRO-C17 was especially good at discriminating between CRC patients and healthy controls with an AUROC of 0.904. In cohort 2, patients with mCRC and high levels (tertile 3) of PRO-C17 had shorter overall survival (OS) with a median OS of 390 days compared to 539 days for patients with low levels of PRO-C17. When evaluated by multivariate Cox regression analysis, high PRO-C17 was predictive for poor OS independent of risk factors and the tumor fibrosis biomarker PRO-C3.

CONCLUSION

PRO-C17 measures the ectodomain of type XVII collagen in serum and is a promising non-invasive biomarker that can aid in understanding tumor heterogeneity as well as elaborate on the role of collagen XVII in tumor progression. Moreover, the findings in the study proposes PRO-C17 as novel biomarker of epithelial damage in specific cancer types including CRC.

Plasma Kallikrein-Activated TGF-β Is Prognostic for Poor Overall Survival in Patients with Pancreatic Ductal Adenocarcinoma and Associates with Increased Fibrogenesis

Pancreatic ductal adenocarcinoma (PDAC) is a hard-to-treat cancer due to the collagen-rich (fibrotic) and immune-suppressed microenvironment. A major driver of this phenomenon is transforming growth factor beta (TGF-β). TGF-β is produced in an inactive complex with a latency-associated protein (LAP) that can be cleaved by plasma kallikrein (PLK), hereby releasing active TGF-β. The aim of this study was to evaluate LAP cleaved by PLK as a non-invasive biomarker for PDAC and tumor fibrosis. An ELISA was developed for the quantification of PLK-cleaved LAP-TGF-β in the serum of 34 patients with PDAC (stage 1−4) and 20 healthy individuals. Biomarker levels were correlated with overall survival (OS) and compared to serum type III collagen (PRO-C3) and type VI collagen (PRO-C6) pro-peptides. PLK-cleaved LAP-TGF-β was higher in patients with PDAC compared to healthy individuals (p < 0.0001). High levels (>median) of PLK-cleaved LAP-TGF-β were associated with poor OS in patients with PDAC independent of age and stage (HR 2.57, 95% CI: 1.22−5.44, p = 0.0135). High levels of PLK-cleaved LAP-TGF-β were associated with high PRO-C3 and PRO-C6, indicating a relationship between the PLK-cleaved LAP-TGF-β fragment, TGF-β activity, and tumor fibrosis. If these preliminary results are validated, circulating PLK-cleaved LAP-TGF-β may be a biomarker for future clinical trials.

Abstract 1568: PLK activated TGF-β functions as a prognostic biomarker for patients with pancreatic ductal adenocarcinoma

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer death with a 5-year survival rate of approximately 7%. Transforming growth factor beta (TGF-β) is highly involved in progression and metastasis in multiple cancers including PDAC. TGF-β is highly involved in tumor fibrosis and immune suppression, and several clinical trials are ongoing to evaluate anti-TGF-β therapies for treating patients diagnosed with cancer and for which biomarkers are key for success. TGF-β is produced in a latent complex with latency-associated protein (LAP), which needs to be cleaved by plasma kallikrein (PLK), releasing TGF-β to enable receptor binding and initiating of signaling. We developed a competitive enzyme-linked immunosorbent assay (ELISA) targeting PLK activated TGF-β and measured it in serum from patients with PDAC.

Methods: An ELISA based on monoclonal antibodies raised against the C-terminal side of the PLK cleavage site of TGF-β at R’58↓ was developed and validated for quantification of PLK activated TGF-β (L59TGF-β) in serum. To confirm that the ELISA was specifically measuring PLK cleaved TGF-β, L59TGF-β was measured in a TGF-β dilution after incubation with and without kallikrein. L59TGF-β was measured in pretreatment serum samples from patients with PDAC (n=39) and healthy controls (n=20). The prognostic value of L59TGF-β levels was examined with Kaplan-Meier analysis and evaluated for association with overall survival (OS) by multivariate cox regression analysis adjusted for age and cancer stage.

Results: L59TGF-β was only detected after incubation with kallikrein, demonstrating that the ELISA specifically detected kallikrein cleaved TGF-β. L59TGF-β was significantly elevated in patients with PDAC compared to healthy controls (p&lt;0.0001). High levels of L59TGF-β (&gt;median) were significantly associated with poor OS (HR: 2.71, 95%CI: 1.23-5.97, p=0.0135) in patients with PDAC, and median OS was 5.5 months (95%CI: 1.50-20.0) compared to 26.3 months (95%CI: 15.3-28.1) for patients with low levels of L59TGF-β. The association between high levels of L59TGF-β and poor OS remained statistically significant after adjusting for age and stage (HR: 2.33, 95%CI: 1.05-5.18, p=0.0372).

Conclusion: Quantification of PLK activated TGF-β (L59TGF-β) in serum predicted poor OS for patients with PDAC. The biomarker value of L59TGF-β should be validated and further investigated in a larger cohort to explore the clinical applicability of the biomarker.

Citation Format: Rasmus S. Pedersen, Neel I. Nissen, Christina Jensen, Jeppe Thorlacius-Ussing, Majken L. Olesen, Lasse Langholm, Tina M. Jensen, Hadi M. Diab, Lars N. Jørgensen, Morten Karsdal, Nicholas Willumsen. PLK activated TGF-β functions as a prognostic biomarker for patients with pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1568.

Fibrotic activity quantified in serum by measurements of type III collagen pro-peptides can be used for prognosis across different solid tumor types

Due to activation of fibroblast into cancer-associated fibroblasts, there is often an increased deposition of extracellular matrix and fibrillar collagens, e.g. type III collagen, in the tumor microenvironment (TME) that leads to tumor fibrosis (desmoplasia). Tumor fibrosis is closely associated with treatment response and poor prognosis for patients with solid tumors. To assure that the best possible treatment option is provided for patients, there is medical need for identifying patients with high (or low) fibrotic activity in the TME. Measuring unique collagen fragments such as the pro-peptides released into the bloodstream during fibrillar collagen deposition in the TME can provide a non-invasive measure of the fibrotic activity. Based on data from 8 previously published cohorts, this review provides insight into the prognostic value of quantifying tumor fibrosis by measuring the pro-peptide of type III collagen in serum of a total of 1692 patients with different solid tumor types and discusses the importance of tumor fibrosis for understanding prognosis and for potentially guiding future drug development efforts that aim at overcoming the poor outcome associated with a fibrotic TME.

Collagen Biomarkers Quantify Fibroblast Activity In Vitro and Predict Survival in Patients with Pancreatic Ductal Adenocarcinoma

The use of novel tools to understand tumour-fibrosis in pancreatic ductal adenocarcinoma (PDAC) and novel anti-fibrotic treatments are highly needed. We established a pseudo-3D in vitro model including humane pancreatic fibroblasts (PFs) and pancreatic cancer-associated fibroblasts (CAFs) in combination with clinical collagen biomarkers, as a translational anti-fibrotic drug screening tool. Furthermore, we investigated the prognostic potential of serum collagen biomarkers in 810 patients with PDAC. PFs and CAFs were cultured in Ficoll-media. Cells were treated w/wo TGF-ß1 and the anti-fibrotic compound ALK5i. Biomarkers measuring the formation of type III (PRO-C3) and VI (PRO-C6) collagens were measured by ELISA in supernatant at days 3, 6, 9, and 12. PRO-C3 and PRO-C6, and their association with overall survival (OS), were evaluated in serum with PDAC (n = 810). PRO-C3 and PRO-C6 were upregulated in CAFs compared to PFs (p < 0.0001.). TGF-ß1 increased PRO-C3 in both PFs and CAFs (p < 0.0001). The anti-fibrotic compound ALK5i inhibited both PRO-C3 and PRO-C6 (p < 0.0001). High serum levels of PRO-C3 and PRO-C6 in patients with PDAC were associated with short OS (PRO-C3: HR = 1.48, 95%CI: 1.29-1.71, p < 0.0001 and PRO-C6: HR = 1.31, 95%CI: 1.14-1.50, p = 0.0002). PRO-C3 and PRO-C6 have the potential to be used both pre-clinically and clinically as a measure of tumor fibrosis and CAF activity.

Capture and Detection of Circulating Glioma Cells Using the Recombinant VAR2CSA Malaria Protein

Diffuse gliomas are the most common primary malignant brain tumor. Although extracranial metastases are rarely observed, recent studies have shown the presence of circulating tumor cells (CTCs) in the blood of glioma patients, confirming that a subset of tumor cells are capable of entering the circulation. The isolation and characterization of CTCs could provide a non-invasive method for repeated analysis of the mutational and phenotypic state of the tumor during the course of disease. However, the efficient detection of glioma CTCs has proven to be challenging due to the lack of consistently expressed tumor markers and high inter- and intra-tumor heterogeneity. Thus, for this field to progress, an omnipresent but specific marker of glioma CTCs is required. In this article, we demonstrate how the recombinant malaria VAR2CSA protein (rVAR2) can be used for the capture and detection of glioma cell lines that are spiked into blood through binding to a cancer-specific oncofetal chondroitin sulfate (ofCS). When using rVAR2 pull-down from glioma cells, we identified a panel of proteoglycans, known to be essential for glioma progression. Finally, the clinical feasibility of this work is supported by the rVAR2-based isolation and detection of CTCs from glioma patient blood samples, which highlights ofCS as a potential clinical target for CTC isolation.

Tramadol and o-desmethyl tramadol clearance maturation and disposition in humans: a pooled pharmacokinetic study

BACKGROUND AND OBJECTIVES

We aimed to study the impact of size, maturation and cytochrome P450 2D6 (CYP2D6) genotype activity score as predictors of intravenous tramadol disposition.

METHODS

Tramadol and O-desmethyl tramadol (M1) observations in 295 human subjects (postmenstrual age 25 weeks to 84.8 years, weight 0.5-186 kg) were pooled. A population pharmacokinetic analysis was performed using a two-compartment model for tramadol and two additional M1 compartments. Covariate analysis included weight, age, sex, disease characteristics (healthy subject or patient) and CYP2D6 genotype activity. A sigmoid maturation model was used to describe age-related changes in tramadol clearance (CLPO), M1 formation clearance (CLPM) and M1 elimination clearance (CLMO). A phenotype-based mixture model was used to identify CLPM polymorphism.

RESULTS

Differences in clearances were largely accounted for by maturation and size. The time to reach 50 % of adult clearance (TM50) values was used to describe maturation. CLPM (TM50 39.8 weeks) and CLPO (TM50 39.1 weeks) displayed fast maturation, while CLMO matured slower, similar to glomerular filtration rate (TM50 47 weeks). The phenotype-based mixture model identified a slow and a faster metabolizer group. Slow metabolizers comprised 9.8 % of subjects with 19.4 % of faster metabolizer CLPM. Low CYP2D6 genotype activity was associated with lower (25 %) than faster metabolizer CLPM, but only 32 % of those with low genotype activity were in the slow metabolizer group.

CONCLUSIONS

Maturation and size are key predictors of variability. A two-group polymorphism was identified based on phenotypic M1 formation clearance. Maturation of tramadol elimination occurs early (50 % of adult value at term gestation).

Inhibitory effect of oral contraceptives on CYP2C19 activity is not significant in carriers of the CYP2C19*17 allele

(1) The purpose of the present study was to examine whether cytochrome P450 2C19 (CYP2C19) in carriers of the CYP2C19*17 allele is inhibited in vivo by oral contraceptives (OC). (2) Retrospective CYP2C19 phenotyping according to omeprazole : 5-OH-omeprazole molar 3 h plasma metabolic ratios (MR) from a population (n = 222) genotyped as CYP2C19*1/*1, CYP2C19*1/*17 and CYP2C19*17/*17 was analysed. Furthermore, 30 women genotyped as CYP2C19*1/*1 (n = 11), CYP2C19*1/*17 (n = 11) and CYP2C19*17/*17 (n = 8) were prospectively CYP2C19 phenotyped during the administration of OC and again after a minimum 5 days break from OC. (3) We found a significantly higher MR in the CYP2C19*1/*1 genotype group that took OC (n = 48) compared with women who did not take OC (n = 31; geometric mean 1.37 vs. 0.83, respectively; P < 0.05). However, in the CYP2C19*1/*17 genotype group, the geometric means of the MR in the 37 women taking OC and the 20 women not taking OC were 0.67 and 0.46, respectively (P > 0.05). In the CYP2C19*1/*1 panel of the prospective cross-over study, we found a significantly higher MR while women were taking the OC compared with the MR during the OC break (geometric mean 1.21 vs. 0.91, respectively; P = 0.0123). However, in the CYP2C19*1/*17 group, the geometric means of the MR with and without OC were 0.77 and 0.65, respectively, compared with 1.05 and 0.79, respectively, in the CYP2C19*17/*17 group (P = 0.20 and 0.17, respectively). (4) In conclusion, we have shown that OC intake inhibits CYP2C19 in homozygous carriers of the CYP2C19 wild type but that the inhibition is not significant in heterozygous and homozygous carriers of the CYP2C19*17 allele.

Linkage disequilibrium between the CYP2C19*17 allele and wildtype CYP2C8 and CYP2C9 alleles: identification of CYP2C haplotypes in healthy Nordic populations

PURPOSE

To determine the distribution of clinically important CYP2C genotypes and allele frequencies in healthy Nordic populations with special focus on linkage disequilibrium.

METHODS

A total of 896 healthy subjects from three Nordic populations (Danish, Faroese, and Norwegian) were genotyped for five frequent and clinically important CYP2C allelic variants: the defective CYP2C8*3, CYP2C9*2, CYP2C9*3, and CYP2C19*2 alleles, and the CYP2C19*17 allele that causes rapid drug metabolism. Linkage disequilibrium was evaluated and CYP2C haplotypes were inferred in the entire population.

RESULTS

Ten CYP2C haplotypes were inferred, the most frequent of which (49%) was the CYP2C wildtype haplotype carrying CYP2C8*1, CYP2C9*1, and CYP2C19*1. The second most frequent haplotype (19%) is composed of CYP2C19*17, CYP2C8*1, and CYP2C9*1. This predicted haplotype accounts for 99.7% of the CYP2C19*17 alleles found in the 896 subjects.

CONCLUSION

CYP2C19*17 is a frequent genetic variant in Nordic populations that exists in strong linkage disequilibrium with wildtype CYP2C8*1 and CYP2C9*1 alleles, which effectively makes it a determinant for a haplotype exhibiting an efficient CYP2C substrate metabolism.

Thallium intoxication treated with long-term hemodialysis, forced diuresis and Prussian blue

A 56-year-old woman, who ingested 2 g of thallium sulfate, was successfully treated with long-term hemodialysis for 200 hours during ten days, combined with forced diuresis and Prussian blue. The effect of the artificial kidney dialysis was determined by repeated analysis of the thallium concentration in the dialysis bath and in blood samples. During the first 120 hours of hemodialysis, 143 mg of thallium was eliminated via the artificial kidney and 110 mg via the urinary tract. The present case of acute thallium intoxication is the first in which long-term hemodialysis has been used in the acute phase together with forced diuresis and Prussian blue. The data obtained are compared to those obtained from cases treated with hemodialysis in the past. It is concluded that treatment with hemodialysis should be considered as an important supplement to treatment with forced diuresis and Prussian blue in cases of thallium intoxication.

The hypoalgesic effect of oxycodone in human experimental pain models in relation to the CYP2D6 oxidation polymorphism

Oxycodone is O-demethylated by CYP2D6 to oxymorphone which is a potent micro-receptor agonist. The CYP2D6 oxidation polymorphism divides the Caucasian population in two phenotypes: approximately 8% with no enzyme activity, poor metabolizers (PM) and the remainder with preserved CYP2D6 activity, extensive metabolizers (EM). The objective of the study was to determine if the analgesic effect of oxycodone in human experimental pain depends on its metabolism to oxymorphone. The analgesic effect of oxycodone was evaluated in a randomized, placebo-controlled, double-blinded, crossover experiment including 33 (16 EM and 17 PM) healthy volunteers. Pain tests were performed before and 1, 2, 3 and 4 hr after medication and included pain detection and tolerance thresholds to single electrical sural nerve stimulation, pain summation threshold to repetitive electrical sural nerve stimulation and the cold pressor test with rating of discomfort and pain-time area under curve (AUC(0-2 min.)). For single sural nerve stimulation, there was a less pronounced increase in thresholds on oxycodone in pain detection (9% vs. 20%, P = 0.02, a difference of 11%, CI: 2%-20%) and pain tolerance thresholds (15% vs. 26%, P = 0.037, a difference of 10%, CI: 1%-20%) for PM compared with EM. In the cold pressor test, there was less reduction in pain AUC on oxycodone for PM compared with EM (14% vs. 26%, P = 0.012, a difference of 12%, CI: 3%-22%). The plasma oxymorphone/oxycodone ratio was significantly lower in PM compared with EM (P < 0.001). Oxycodone analgesia seems to depend both on oxycodone itself and its metabolite oxymorphone.

The effects of human CYP2C8 genotype and fluvoxamine on the pharmacokinetics of rosiglitazone in healthy subjects

AIMS

To determine the effect of CYP2C8 genotype and of fluvoxamine on the pharmacokinetics of rosiglitazone.

METHODS

Twenty-three healthy subjects with the following genotypes were included in a two-phase, open-label, cross-over trial: CYP2C8*3/ *3 (n = 3), CYP2C8*1/ *3 (n = 10) and CYP2C8*1/ *1 (n = 10). In Phase A, the subjects were given 4 mg rosiglitazone as a single oral dose. In Phase B, the subjects were treated with multiple oral doses of 50 mg fluvoxamine maleate for 3 days prior to the single oral administration of 4 mg rosiglitazone. Plasma concentrations of rosiglitazone and relative amounts of N-desmethylrosiglitazone were measured in both phases for 24 h after drug administration.

RESULTS

The pharmacokinetics of rosiglitazone and N-desmethylrosiglitazone were not significantly different between the CYP2C8 genotypic groups. Fluvoxamine caused a statistically significant (P = 0.0066) increase in the AUC(0-infinity) of rosiglitazone, with a geometric mean ratio of 1.21 [95% confidence interval (CI) 1.06-1.39]. The elimination half-life (t(1/2)) was also significantly higher (P = 0.0203) with a geometric mean ratio of 1.38 [95% CI 1.06-1.79]. The coadministration of fluvoxamine had no influence on the pharmacokinetics of N-desmethylrosiglitazone.

CONCLUSION

The importance of the CYP2C8*3 mutation in the in vivo metabolism of rosiglitazone could not be confirmed. Fluvoxamine increased the AUC(0-infinity) and t(1/2) of rosiglitazone moderately and hence may be a weak inhibitor of CYP2C8.

Paroxetine, a cytochrome P450 2D6 inhibitor, diminishes the stereoselective -demethylation and reduces the hypoalgesic effect of tramadol

OBJECTIVE

Tramadol hydrochloride (INN, tramadol) exerts its antinociceptive action through a monoaminergic effect mediated by the parent compound and an opioid effect mediated mainly by the O-demethylated metabolite (+)-M1. O-demethylation is catalyzed by cytochrome P450 (CYP) 2D6. Paroxetine is a very potent inhibitor of CYP2D6. The objective of this study was to investigate the influence of paroxetine pretreatment on the biotransformation and the hypoalgesic effect of tramadol.

METHODS

With and without paroxetine pretreatment (20 mg daily for 3 consecutive days), the formation of M1 and the analgesic effect of 150 mg of tramadol were studied in 16 healthy extensive metabolizers of sparteine in a randomized, double-blind, placebo-controlled, 4-way crossover study by use of experimental pain models.

RESULTS

With paroxetine pretreatment, the area under the plasma concentration-time curve (AUC) of (+)- and (-)-tramadol was increased (37% [P = .001] and 32% [P = .002], respectively), and the corresponding AUCs of(+)- and (-)-M1 were decreased (67% [P = .0004] and 40% [P = .0008], respectively). (+)-M1 and (-)-M1 could be determined in all subjects throughout the study period regardless of paroxetine pretreatment. The sums of differences between postmedication and premedication values of pain measures differed between the placebo/tramadol and the placebo/placebo combination, with median values as follows: pressure pain tolerance threshold, 390 kPa (95% confidence interval [CI], 211 to 637 kPa) versus -84 kPa (95% CI, - 492 to -32 kPa) (P = .001); single sural nerve stimulation pain tolerance threshold, 25.8 mA (95% CI, 15.3 to 29.8 mA) versus 9.0 mA (95% CI, 1.5 to 14.8 mA) (P = .005); pain summation threshold, 10.7 mA (95% CI, 5.2 to 17.6 mA) versus 5.0 mA (95% CI, 2.8 to 11.2 mA) (P = .066); cold pressor pain, -4.2 cm x s (95% CI, -6.8 to -1.9 cm x s) versus -0.4 cm x s (-1.4 to 1.4 cm x s) (P = .002); and discomfort, -4.7 cm (95% CI, -10.6 to -2.8 cm) versus 0.5 cm (-0.1 to 1.4 cm) (P = .002). The sums of differences of the paroxetine/tramadol combination also differed from placebo/tramadol for some of the measures, with median values as follows: cold pressor pain, -2.2 cm x s (95% CI, -3.7 to -0.4 cm x s) (P = .036, compared with placebo/tramadol); and discomfort, -2.0 cm (95% CI, -5.6 to -1.2 cm) (P = .056). For the other measures, the hypoalgesic effect was retained on the paroxetine/tramadol combination, with median values as follows: pressure pain tolerance threshold, 389 kPa (95% CI, 141 to 715 kPa) (P = .278, compared with placebo/tramadol); single sural nerve stimulation pain tolerance threshold, 12.5 mA (95% CI, 6.2 to 28.3 mA) (P = .278); and pain summation threshold, 8.2 mA (95% CI, 4.4 to 14.6 mA) (P = .179). Paroxetine in combination with placebo showed no analgesic effect.

CONCLUSIONS

It is concluded that paroxetine at a dosage of 20 mg once daily for 3 consecutive days significantly inhibits the metabolism of tramadol to its active metabolite M1 and reduces but does not abolish the hypoalgesic effect of tramadol in human experimental pain models, particularly in opioid-sensitive tests.

Effect of an acute oral lithium intake on urinary Aquaporin-2 in healthy humans with and without simultaneous stimulation with hypertonic saline infusion

OBJECTIVE

Animal experiments have shown that lithium interferes with the formation of Aquaporin-2 in the distal renal tubuli. The effect of lithium on formation of renal water channels has not been studied in healthy humans. The aim of this study was to test the hypotheses that a single oral dose of lithium will reduce the formation of water channels both with and without stimulation with hypertonic saline infusion, and that this effect can be detected by measurement of urinary excretion of Aquaporin-2 (u-AQP2).

METHODS

In healthy subjects, Study 1 (n = 11) and Study 2 (n = 12), urine was collected in 6 and 7 periods between 08.00 and 14.00, respectively, and blood samples were drawn at 30- to 60-min intervals. The study medication was given at 09.00; u-AQP2 was determined by radioimmunoassay.

RESULTS

In Study 1 neither u-AQP2 nor urinary output were significantly changed by lithium. In Study 2, u-AQP2 was increased by hypertonic saline infusion in parallel with an increase in arginine vasopressin. At the end of the study, u-AQP2 was increased by 30% with placebo but only by 13% with the 600 mg lithium dose, and urinary output was significantly higher after 600 mg lithium than after placebo and 300 mg lithium.

CONCLUSIONS

U-AQP2 was not significantly changed after a single oral dose of lithium. The antidiuretic response to hypertonic saline infusion was reduced when lithium was given. It is suggested that lithium increases urinary output by inhibiting trafficking of renal water channels in healthy humans.

Influence of training habits on exercise-induced changes in plasma atrial and brain natriuretic peptide and urinary excretion of aquaporin-2 in healthy man

The purpose of this study was to quantify the influence of training habits on the changes in plasma atrial natriuretic peptide (ANP), plasma brain natriuretic peptide (BNP) and urine aquaporin-2 (u-AQP2) during exercise by studying trained and untrained healthy subjects. Eleven trained subjects (7 males, 4 females) and 10 untrained subjects (8 males, 2 females) performed a maximal aerobic exercise test. ANP and BNP were determined every 3 min and at maximum exercise by radioimmunoassay (RIA), and u-AQP2 was determined before and after the exercise test by RIA. The absolute increase in ANP during exercise was higher in the trained subjects (trained subjects: 5.6 pmol/L; untrained subjects: 2.4 pmol/L, p < 0.05) and was positively correlated to ANP at rest (p < 0.03). The maximum absolute increase in BNP during exercise was the same in the two groups (trained subjects: 0.5 pmol/L; untrained subjects: 0.6 pmol/L, NS) and tended to correlate positively with resting BNP in the trained subjects (p = 0.07). Exercise did not change u-AQP2 excretion in either trained subjects (rest: 372 ng/mmol creatinine; exercise: 314 ng/mmol creatinine, NS) or untrained subjects (rest: 263 ng/mmol creatinine; exercise: 338 ng/mmol creatinine, NS). The absolute increase in ANP during exercise was higher in trained subjects than in untrained subjects and was positively correlated to ANP at rest. This might reflect the normal cardiovascular adaptation to exercise. The increase in BNP during exercise was unrelated to training habits. Training habits did not affect the u-AQP2 excretion during exercise.

Chlamydia pneumoniae DNA in peripheral blood mononuclear cells in dialysis patients, renal transplant recipients and healthy controls

It has been suggested that infection with Chlamydia pneumoniae plays a role in the development and maintenance of atherosclerosis based on differences in the prevalence of antibodies against Chlamydia pneumoniae in patients with and without atherosclerotic lesions and on the presence of bacteria in atherosclerotic lesions. It is well known that patients undergoing chronic dialysis treatment and renal transplant recipients have a considerably increased risk of cardiovascular disease. In this study it is hypothesized that patients with these conditions have a higher prevalence of Chlamydia pneumoniae DNA in the white cells of the peripheral blood. Blood samples from 196 dialysis patients, 114 renal transplant recipients and 342 healthy controls were analysed with an in-house nested polymerase chain reaction (nPCR) and tested for the presence of Chlamydia pneumoniae DNA. The prevalence of Chlamydia pneumoniae DNA was significantly higher in dialysis patients (16.3%) than in healthy controls (8.5%, p < 0.01), whereas no significant difference was found between the prevalence in renal transplant recipients (9.6%) and healthy controls. The prevalence was not related to gender or age in either group, and it was the same in diabetics and non-diabetics. Dialysis patients have a higher prevalence of Chlamydia pneumoniae DNA than healthy controls. The lower prevalence of Chlamydia pneumoniae DNA in renal transplant recipients than in dialysis patients may be due to selection of dialysis patients with few or no cardiovascular complications for renal transplantation. Our results are consistent with the hypothesis that Chlamydia pneumoniae is associated with the pathogenesis of atherosclerosis.

Effect of an acute oral ibuprofen intake on urinary aquaporin-2 excretion in healthy humans

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the enzyme cyclooxygenase and thereby block the prostaglandin (PG) synthesis in the kidneys. In animals, PG interferes with the formation of aquaporin 2 in the distal renal tubules. The purpose was to measure the effect of ibuprofen on urinary excretion of aquaporin-2 (u-AQP2), urinary output, urinary osmolality (u-osm) and plasma concentration of vasopressin (AVP) in a dose-response study using placebo and ibuprofen 600mg and 1200mg. In 12 healthy subjects, urine was collected in 6 periods between 07.00 h and 13.00 h, and blood samples were drawn at 60-min intervals. The study medication was given 10 h and 1 h before the study. U-AQP2 and AVP were determined by radioimmunoassays. U-AQP2 decreased 33% in the placebo group and increased 47% in the ibuprofen groups. There was a highly significant difference between the placebo group, on the one hand, and the ibuprofen groups, on the other. There was a small but significant increase in AVP in the placebo group and the 600 mg ibuprofen group, but not in the 1200 mg ibuprofen group. Urinary output was at maximum after 2 h, with a 394%, 1020% and 714% increase for placebo, 600 mg ibuprofen and 1200 mg ibuprofen, respectively. U-osm decreased during the experiment in all three groups. Inhibition of renal prostaglandin synthesis by ibuprofen affects the distal part of the nephron by increasing u-AQP2. This increase was not related to changes in AVP, urinary output or urinary osmolality. We suggest that the increased excretion of AQP2 can be explained by an increase in the ratio of AQP2 that is shed into the urine because the endocytic retrieval of AQP2 from the apical membrane is impaired. This could not be revealed by changes in the osmoregulatory system by the low doses of ibuprofen used in the present study.

Effect of water deprivation and hypertonic saline infusion on urinary AQP2 excretion in healthy humans

Arginine vasopressin (AVP) mediates water transport in the renal collecting ducts by forming water channels of aquaporin-2 (AQP2) in the apical plasma membrane. AQP2 is excreted in human urine. We wanted to test the hypothesis that urinary excretion of AQP2 (u-AQP2) reflects the effect of AVP on the renal collecting ducts during water deprivation and hypertonic saline infusion in healthy subjects. Fifteen healthy subjects underwent a 24-h period of fluid restriction. Urine and blood samples were collected at timed intervals. Fifteen healthy subjects were given 7 ml/kg 3% hypertonic saline infusion for 30 min. Urine and blood samples were collected at timed intervals. During fluid restriction, the u-AQP2 rate increased from 3.9 (25th percentile: 3.1; 75th percentile: 5.2) to 7.6 (5.9-9.1; P < 0.001) ng/min, and the plasma AVP (p-AVP) level increased from 0.5 (0.4-0.6) to 3 (1.7-3.3) pmol/l. There was a positive correlation between the maximum change in u-AQP2 rate and the maximum change in p-AVP (r = 0.57, P < 0.03). During the infusion study, u-AQP2 rate was at maximum 90 min after the infusion [baseline: 4.5 ng/min (3.5-4.8); 90 min: 5 ng/min (4.5-6.0) P < 0.02]. p-AVP increased from 1.0 (0.9-1.1) to 1.5 (1.2-1.8; P < 0.002) pmol/l. There was a positive correlation between the maximum change in u-AQP2 rate and the maximum change in p-AVP (r = 0.83; P < 0.0001). It can be concluded that p-AVP and u-AQP2 are increased during thirst and hypertonic saline infusion and that u-AQP2 reflects the action of AVP on the collecting ducts.

Randomized placebo-controlled trial of perindopril in normotensive, normoalbuminuric patients with type 1 diabetes mellitus

Diabetic nephropathy is one of the leading causes of end-stage renal disease. We examined whether ACE inhibitor treatment may have a nephroprotective effect in normotensive insulin-dependent diabetic patients without microalbuminuria and with normal glomerular filtration rate (GFR), and whether any effect was associated with the ACE genotype. In a prospective double-blind randomized study, normotensive patients with type 1 diabetes mellitus with normal serum creatinine and no microalbuminuria were treated with either placebo or perindopril, an ACE inhibitor. Urine albumine/creatinine ratio (ACR), mean blood pressure (MBP) and index of glomerular filtration rate (GFR) based on S-creatinine were determined. ACE genotype was determined by electrophoresis. ACR was higher in the placebo group than in the perindopril group after 4 months, and continued to increase during the study period. After 36 months of observation, ACR in the placebo group was 1.7+/-1.1 mg/mmol, and 0.6+/-0.2 mg/mmol in the ACE-inhibitor-treated group (p<0.001, Mann-Whitney test). During treatment, a significant increase in ACR in the placebo group (p=0.007), Wilcoxon matched paired test) was observed. There were no differences between the groups regarding MBP or GFR. The nephroprotective effects of ACE inhibitor treatment was not associated with the ACE genotype (II, ID, DD).

Staphylococcus aureus carriage in adult peritoneal dialysis patients and their spouses

OBJECTIVE

We hypothesized that carriage of Staphylococcus aureus among continuous ambulatory peritoneal dialysis (CAPD) patients was influenced by their spouses. Furthermore, this carrier status was compared to previous Staph. aureus peritonitis episodes in order to identify the influence of Staph. aureus carriage on peritonitis rate.

DESIGN

A combined prospective surveillance study (Staph. aureus carriage) and retrospective chart review (Staph. aureus peritonitis).

SETTING

A single peritoneal dialysis unit in a county hospital.

PATIENTS AND METHODS

Cultures from patients (n = 32) and spouses (n = 16) were obtained twice, with a 1-month interval, from the anterior nares, the umbilical, and one groin area. All positive cultures were phage typed. Retrospective chart review of all episodes of Staph. aureus peritonitis among the patients was carried out.

RESULTS

Twelve of 32 patients (37.5%) and 5 of 16 spouses (31%) evaluated were carriers. Half of the spouses of patients who were Staph. aureus carriers, were also carriers, as opposed to 20% of spouses of noncarrier patients (p = 0.30). Patients and spouses always shared the same phage type. Among patients, Staph. aureus was found in the nose only (n = 9), in all three regions (n = 2), and extranasally only (n = 1). If only one nasal culture was used to establish carriage, the sensitivity and negative predictive value would be 92% and 95%, respectively. A trend toward a higher incidence (p = 0.062) of Staph. aureus peritonitis was found among carriers (patients), 0.37 versus 0.28 peritonitis episode/dialysis-year.

CONCLUSIONS

Only one positive nasal culture was necessary when carriage of Staph. aureus was to be established. Staph. aureus carriage was found more often in patients who had previously suffered from Staph. aureus peritonitis. The phage types isolated remained fairly constant, and the patients and spouses often had the same carrier state and shared the same phage types, although transmission does not always take place.

Etoposide: more effective and less bone-marrow toxic than standard immunosuppressive therapy in systemic vasculitis?

In two patients suffering from ANCA-positive systemic vasculitis (one from Wegener's granulomatosis, the other from microscopic polyangiitis), who were both resistant to or could not tolerate standard immunosuppressive therapy, complete clinical and biochemical remission was obtained within few months, treating with cyclic etoposide. Etoposide therapy was found to be significantly less bone marrow toxic than standard immunosuppressive therapy.

Continuous venovenous haemodialysis: a three-pump system

A simple three-pump-based system for the performance of continuous venovenous haemodialysis is described. The method employs access to the circulation via a double-lumen catheter, and by means of a standard extracorporeal peristaltic pump the blood is circulated through a haemofiltration filter. Standard solutions for peritoneal dialysis are administered in a single-pass manner countercurrent to the blood flow. To control the dialysate flow through the filter, two separate pumps designed for intravenous infusion are used. Anticoagulation is achieved by means of continuous heparin infusion. This three-pump system is effective in controlling the fluid balance and the level of azotemia. Furthermore, this system makes haemodialysis possible in spite of severe haemodynamic instability. The system is easy to use and inexpensive. 3 patients participated in the study.

Long-term prognosis in idiopathic membranoproliferative glomerulonephritis

The following results were obtained in a long-term follow-up investigation including 37 patients who suffered from idiopathic membranoproliferative glomerulonephritis. The mean follow-up period was 51 months (median 32 months). 1) Renal survival was 35% at 5 years and 16% at 10 years. 2) Univariate analysis indicated significant (p < or = 0.10) association between poor prognosis and the two following parameters a) high age b) elevated blood pressure. 3) Using a Cox-analysis including a) gender b) age at kidney biopsy c) square of age (age age) at biopsy d) presence of nephrotic syndrome e) presence of elevated blood pressure, the following p-values were found: 0.56; 0.02; 0.04; 0.50; 0.09. Thus at the 10% level age, the square of age and elevated blood pressure were significant and independently associated with poor prognosis.

[Peritonitis among patients treated with continuous ambulatory peritoneal dialysis]

A retrospective study of 51 consecutive patients treated with continuous ambulatory peritoneal dialysis (CAPD) during a total of 736 months is presented. Forty-one episodes of peritonitis were found. Thirty-three patients did not experience peritonitis. One patient had six episodes of peritonitis. The time to first and second episode of peritonitis was 487 days (16.2 months) and 1005 days (33.5 months) respectively. The incidence of peritonitis was 0.67 episodes per patient-year, and was not influenced by either sex, diabetes or previous abdominal surgery. The time to the first episode of peritonitis was equal in patients suffering from one vs two or more episodes of peritonitis. Two patients suffered from tunnel infection. Initial treatment with vancomysin and gentamycin (before knowing the results of microbiological culturing) was adequate in 90% of the peritonitis episodes. Sterile peritonitis was found in 12% of the cases. No relapse of peritonitis was observed. Six patients suffered from eleven cases of reinfection. An optimal surgical strategy as well as vancomycin plus gentamicin treatment of peritonitis are advised when a reduction in infection rates is required

Ultrasound-guided renal biopsy with biopsy gun technique--efficacy and complications

One hundred and thirty-one ultrasound-guided renal biopsies performed in 127 patients with automated spring-loaded biopsy technique were evaluated. Adequate tissue for histologic diagnosis was obtained in 92% of the procedures (94% of the patients). The mean glomerular yield was 16.8 glomeruli. Complications were seen in 21% of the patients, 18% having minor and 3% having major complications. Patients with severe hypertension had significantly more complications than the rest of the patients. The rate of complications in patients who had 3 or 4 biopsy passes was not increased compared to patients who had one or 2 biopsy passes. Thus, this study indicates that the risk of complications and the safety of the procedure is not influenced by increasing the number of biopsy passes in order to obtain representative specimens.

[Short and long term prognosis of acute renal failure requiring dialysis. An analysis of 419 consecutive patients]

To describe the relationship between morbidity, mortality, and year of admission we studied 419 patients with acute dialysis-requiring renal failure. Effects of various follow-up periods and stratification on main prognostic factors were evaluated. There was a significantly higher (p < 0.001) number of organ failures/patient during the second six-year period compared with the first six-year period. Early (day 90) mortality was 46% and unchanged during the period. Estimated five year survival rate (95% confidence limits) was 52% (44-60) in patients with a medical etiology, and 28% (20-36) in patients with a surgical etiology. Prognosis was dependent on the severity and progression of the underlying disease process. Changed censoring time and stratification were important tools for enhancing the yield of information from the study. Time(s) and method(s) of risk scoring, stratification(s) of patients, time(s) of censorship, and method of statistical analysis should be identical when comparing results of treatment for acute renal failure from different centres.

Henoch-Schönlein purpura associated with Campylobacter jejuni enteritis. Case report

After an episode of enteritis caused by C. jejuni a 15-year-old boy developed Schönlein-Henoch purpura. Because of continuous proteinuria a renal biopsy was performed. Light microscopy revealed focal proliferative glomerulonephritis. IgA was the dominant immunoglobulin. A causal relationship between enteritis caused by C. jejuni and Schönlein-Henoch purpura complicated with focal proliferative glomerulonephritis is suggested.

Short and long term outcome in a consecutive series of 419 patients with acute dialysis-requiring renal failure

This analysis was done in a consecutive series of 419 patients with potentially reversible acute renal failure (ARF) requiring dialysis treated during the 12 year period January 1977 to December 1988. The aims were to describe the relationship between morbidity, mortality, and the year of admission, to evaluate the effects of various follow-up periods and stratification on main prognostic factors, and to report long term survival.

RESULTS

1) There was a significantly higher (p < 0.001) number of organ failures/patient in the last 6 year period compared with the first 6 year period. 2) Early (day 90) mortality was 46% and did not change significantly during the 12 year period. 3) Etiology, age of the patient, and the severity and the progression of the underlying disease were the most important factors determining outcome. 4) Time of censorship and stratification of the patients influenced prediction models. 5) Estimated 5 year survival rate was 52% (95% confidence limits 44-60%) in patients with a medical etiology, and 28% (95% confidence limits 20-36%) in patients with a surgical etiology.

CONCLUSIONS

1) Prognosis did not change significantly during the 12 year study period, and was almost solely dependent on the severity and progression of the underlying disease process. 2) Changed censoring time and stratification were important tools for enhancing the yield of information from the study. 3) The time(s) and method(s) of risk scoring, stratification(s) of patients, the time(s) of censorship on vital status, and the method for statistical analysis have to be identical if results of treatment for ARF from different centers should be compared.

Prognosis in septicemia complicated by acute renal failure requiring dialysis

During a 12-year period 419 patients were admitted because of acute renal failure requiring dialysis. Fifty (12%) had septicemia verified by blood culture. In a retrospective study age, sex, focus of infection, blood culture results, kidney function, mode of dialysis treatment, numbers and durations of complicating organ failures, presence of gastrointestinal bleeding, and secondary complicating events of septicemia were recorded for the purpose of establishing a prognostic index based on clinical criteria. Respiratory failure was present in 34 patients, circulatory failure in 31 patients, failure of coagulation system in 25 patients, and hepatic failure in 10 patients. Overall mortality was 46%. Highest death-rates were found during the first days of dialysis. In patients with multiple organ failures, in elderly and in patients suffering from staphylococcus aureus septicemia, a non-significant trend towards higher mortality was found. The mode of dialysis treatment did not influence patient survival. Our intention of establishing a prognostic index based on bedside clinical criteria has not been fulfilled. Even though mortality-rate increases in patients with acute renal failure complicated by failure of one or more vital organs, survival-rate in patients with four or more organ failures was 30%.

Prognosis and risk factors in acute, dialysis-requiring renal failure after open-heart surgery

Of 1988 patients who underwent open-heart surgery from 1980 through 1988, 68 (3.4%) developed postoperative acute renal failure requiring dialysis (2.5% of adult and 8.3% of pediatric patients). Isolated aortocoronary bypass grafting was the operation with lowest incidence of this complication (0.6%). Acute renal failure usually appeared during the first 3 postoperative days. It carried a mortality rate of 63%, with half of the deaths occurring during the first few postoperative days, due to low cardiac output and progressive multiple organ failure. Logistic regression analysis in cases of aortic valve replacement demonstrated that significant independent preoperative risk factors for acute renal failure were renal insufficiency (serum creatinine greater than 110 mumol/l in greater than or equal to 2 samples) and increased cardiothoracic index/left ventricular end-diastolic dimension. Data from the literature indicated no time-related trend towards reduction of acute renal failure incidence or mortality. Prevention of low cardiac output is of major importance in these respects. Operative intervention before development of advanced disease with left ventricular dilatation and secondary kidney failure is advocated.

Hemodialysis does not always protect against recurrence of Wegener's granulomatosis

Hemodialysis may protect against disease activity in Wegener's granulomatosis. We report here a 41-year-old woman with Wegener's granulomatosis, in whom renal transplantation was performed after a 10-month period of hemodialysis during which no signs of disease activity were detected. Recurrence of disease did, however, take place 2 years after renal allograft transplantation despite immunosuppressive therapy with cyclosporine A and prednisone. Reinstitution of hemodialysis and graftectomy did not improve the patient's condition but plasmapheresis and treatment with cyclophosphamide and prednisone eliminated all signs of disease within a fortnight. A proposal for better maintenance of these patients is made.

[18 children with slight glomerular proteinuria demonstrated incidentally]

Out of 61 children with idiopathic chronic glomerulonephritis confirmed by biopsy or minimal lesion diagnosed during the period 1964-1987, 18 were found in whom the first sign of renal disease was slight proteinuria demonstrated at routine examination of the urine. Five of these children were referred directly to a nephrological department with the object of further elucidation of the diagnosis. In six of the remaining 13 children, the first referral to hospital took place after an average of 5.9 years and after signs of renal disease were apparent for the first time. In ten of these 13 patients, an average period of 3.9 years elapsed before renal biopsy was carried out and the nature of the disease elucidated. 29 and 73% of these patients, respectively, had developed terminal uraemia five and ten years after establishing the diagnosis. It is recommended that children in whom persistent proteinuria is demonstrated, regardless of the magnitude, should be referred directly to a nephrological department or a paediatric department with special interests. Renal biopsy may be indicated. Life-long systematic follow-up control is indicated.

[Extracorporeal treatment of poisoning. An analysis of 72 consecutive cases from the period 1977-1988]

During a period of 12 years, extracorporeal treatment of 72 cases of poisoning in the form af dialysis and/or haemoperfusion was undertaken in Medical Department C of Arhus Municipal Hospital. Where 54 patients were concerned, the causes of poisoning were medicinal. Eleven cases were caused by ethyl alcohol, six were caused by technical poisons and one by cantharidine which is employed in veterinary medicine. In 50 cases the primary indication for extracorporeal treatment was elimination of the drug or other poison. In the remaining 22 cases the indication was acute renal failure. The total mortality was 4%.

Acute renal failure caused by polymyxin B containing ointment

A case is presented in which a 67-year-old man suffering from non-insulin-dependent diabetes mellitus, after being treated with polymyxin B containing ointment for leg ulcers, developed acute renal failure. After a period of 13 days during which the patient was treated with peritoneal dialysis 5 times, renal function returned. At discharge creatinine-clearance was 12 ml/min. Treating large ulcers with polymyxin B may be dangerous.