Niels Bindslev

The treatment effect of alpha interferon in chronic hepatitis B is independent of pre-treatment variables. Results based on individual patient data from 10 clinical controlled trials

Alpha interferon induces HBeAg seroconversion in about one third of treated patients and has become an established treatment of chronic hepatitis B. A number of smaller studies have suggested that response to treatment is more likely to occur in patients with higher levels of transaminases, with recent (adult) onset, a history of acute hepatitis, low levels of HBV DNA and in heterosexual males. The aim of this European co-operative study was to estimate the effect of alpha interferon more accurately and to evaluate the influence of host pre-treatment variables on the effect of interferon. Individual data were collected from 751 patients from 10 controlled clinical trials on alpha interferon (lymphoblastoid or recombinant) treatment for chronic hepatitis B. Alpha interferon was administered to 496 patients, while 255 were untreated controls. Individual patient data were analysed by survival analysis (log rank test and Cox regression analysis), stratified by trial, with the disappearance of HBeAg as the major endpoint. The results showed that the HBeAg disappearance rate with or without interferon treatment was higher in patients with high aminotransferase levels, with a history of acute hepatitis and in male heterosexual patients disregarding HIV status. If HIV-positive patients were excluded, the effect of sexual orientation was not significant. Therapy with alpha interferon increased the a priori HBeAg disappearance rate by a factor of 1.76; the relative treatment effect of alpha interferon was independent of the tested pretreatment host variables, but dependent on the total (intended) interferon dose (low dose < or = 200 MU/m2 increased HBeAg disappearance by a factor 1.37; medium/high dose > or = 200 MU/m2 increased HBeAg disappearance by a factor 2.05). In conclusion, this meta-analysis suggests that the effect of alpha interferon is less than previously assumed and independent of pretreatment host variables tested. It confirms the higher therapeutic benefit of a total dose exceeding 200 MU/m2 and of selection of patients based on disease activity and immune reactivity. Although all patient seem to have the same relative benefit, the absolute benefit of alpha interferon treatment seems to be greatest in patients with high transaminase levels and with a history of acute hepatitis.

Sodium chloride absorption and solute‐linked water flow across the epithelium of the coprodeum and large intestine in the normal and dehydrated fowl (Gallus domesticus). In vivo perfusion studies

1. The transmural net flow of salt and water in the coprodeum and large intestine of normal and dehydrated hens was investigated by means of an intraluminal in vivo perfusion technique. The lumen was perfused with hypo‐, iso‐, and hyperosmotic salt solutions. Polyethylene glycol (PEG 4000) and [14C]inulin served as water markers.

Prednisolone withdrawal therapy enhances the effect of human lymphoblastoid interferon in chronic hepatitis B

BACKGROUND/AIMS The aim of this multicentre, randomised, controlled, clinical trial was to evaluate the effect of prednisolone followed by lymphoblastoid interferon treatment in chronic hepatitis B. METHODS Two hundred and thirteen patients with chronic hepatitis B were randomised to either prednisolone (2 weeks of 0.6 mg/kg/day, 1 week of 0.45 mg/kg/day and 1 week of 0.25 mg/kg/day) or matching placebo followed by a 2-week rest phase and then human lymphoblastoid interferon 10 MU daily for 5 days followed by 10 MU thrice weekly for 11 weeks. Of 200 evaluable patients, 33 (16.5%) were females, and 50 (25%) were male homosexuals. Thirty three patients (16.5%) had chronic persistent hepatitis, 145 (72.5%) had chronic active hepatitis and 22 (11%) had active cirrhosis. RESULTS Survival analysis disclosed statistically significant effects of prednisolone pre-treatment on both HBeAg disappearance and HBeAg to anti-HBe seroconversion (log-rank test statistics 5.43; p = 0.02 and 4.75; p = 0.03). Observed HBeAg disappearance and HBeAg to anti-HBe seroconversion rates (placebo vs. prednisolone patients) were 28% vs. 44% and 23% vs. 38%. Six months after stopping interferon, HBV DNA was negative in 51% of prednisolone patients vs. 28% of placebo patients (Chi-square test statistic 6.13; p = 0.013). Prednisolone pre-treatment tended to be more effective in patients with higher transaminase levels and in patients with low levels of HBV DNA. Fifteen patients (7.5%) (13 within 1 year of follow-up) eventually lost HBsAg; 14 of these subsequently developed anti-HBs. Interferon treatment was modified in 102 patients (51%). Three out of 22 patients with cirrhosis (14%), one of whom received prednisolone pre-treatment, developed hepatic decompensation with a fatal outcome while on interferon treatment. CONCLUSIONS Prednisolone pre-treatment significantly enhanced the treatment effect of lymphoblastoid interferon in terms of HBeAg clearance and seroconversion to anti-HBe. Treatment should be used with caution in patients with cirrhosis and avoided in patients showing signs, or with a history, of decompensated cirrhosis.

Fluctuation analysis of short-circuit current in a warm-blooded sodium-retaining epithelium: Site current, density, and interaction with triamterene

SummaryDensity and conductance of the Na-site in hen coprodeum were studied by employing fluctuation analysis of shortcircuit current at sodium concentrations from 26 to 130mm. Fluctuations of current in the frequency range 2–800 Hz were induced by triamterene, a reversible blocker of conducting epithelial Na-sites. At 130mm Na the site density was 5.8±1.0 μm−2 and the site conductance was 4 pS. This conductance is equal to that of the frog skin (W. Van Driessche and B. Lindemann, 1979,Nature (London)282:519–520). Extrapolation of site density to zero sodium renders a total of 38±28 sites μm−2, which is compared with other estimates for the coprodeum. The site-triamterene association and dissociation constants were 9.5±0.4 rad sec−1 μm−1 and 255±20 rad sec−1 and they were independent of external sodium concentration. An analysis of the affinity constant for triamterene based on the DC-short-circuit current was found to be unrelated to the external sodium concentration and identical to that obtained from fluctuation analysis indicating a noncompetitive interaction between sodium and triamterene. Due to the oxygen demand of the epithelium we have developed an experimental method using short data processing times. A new analytical approach using integration of the power density spectrum proved necessary because of low signal-to-noise ratios.

Salt and water permeability of the epithelium of the coprodeum and large intestine in the normal and dehydrated fowl (Gallus domesticus). In vivo perfusion studies

1. The transmural net flow of salt and water in the coprodeum and large intestine of normal and dehydrated hens was investigated by means of an intraluminal in vivo perfusion technique.

Na/D-Glucose Cotransport and SGLT1 Expression in Hen Colon Correlates with Dietary Na+

We have tested whether separately varying the content of either Na or Cl in diets causes earlier observed increase in Na-coupled sugar and amino acid transport induced by high NaCl diets in hen colon. A comparison was also made between the dependence of the Na-coupled transport on a pure wheat/barley/soya diet against a diet with supplements of essential amino acids, fatty acids, vitamins, and trace elements, as a test for possible elimination of the cotransporters due to a deficient diet. Na/nutrient-coupled transport was measured as changes in short circuit current. The level of expressed Na/glucose cotransporters, SGLT1, due to dietary alterations was followed by quantitative Western blot and immunodetection of SGLT1 in colon, and the dietary effects on plasma aldosterone were assessed as well. An observed switch in transport from amiloride-sensitive electrodiffusive Na transport to phlorizin-sensitive Na/D-glucose cotransport and Na/amino acid-coupled transport is caused solely by increasing Na+ in the diet. Thus, neither dietary Cl- nor the dietary supplements altered the expression of Na(+)-coupled nutrient transport processes. Corroborating these findings, only Na+ in the diet increased the expression of SGLT1 in colon epithelium and suppressed aldosterone level in plasma.

Possible epithelial sodium channels visualized by freeze-fracture

The coprodeum is a very efficient Na+-retaining epithelium. Coprodeum from birds on a high Na+ diet has virtually no ion transport, while an Amiloride-sensitive Na+ absorption of 10--12 mu equiv . cm-2 . h-1 is induced in the coprodeal epithelium from birds on a low Na+ diet. Both measurements of the Na+ influx and Na+-diffusion potentials across the luminal cell membrane have revealed a selective opening of this membrane to Na+ in birds on a low Na+ diet. Freeze-fracture P faces of the luminal membrane in coprodea taken from birds on a low Na+ diet have rod-shaped particles, 100 x 240 A, in more than 20% of the principal cells. Rod-shaped particles appear in less than 1% of these cells in coprodea from high Na+-diet birds. Thus a low Na+ diet induces rod-shaped particles in the luminal cell membrane of the hen coprodeum. These new particles may function as Na+-channels mediating the increased Na+-influx across the apical cell membrane.

Transporter function and cyclic AMP turnover in normal colonic mucosa from patients with and without colorectal neoplasia

BackgroundThe pathogenesis of colorectal neoplasia is still unresolved but has been associated with alterations in epithelial clearance of xenobiotics and metabolic waste products. The aim of this study was to functionally characterize the transport of cyclic nucleotides in colonic biopsies from patients with and without colorectal neoplasia.MethodsCyclic nucleotides were used as model substrates shared by some OATP- and ABC-transporters, which in part are responsible for clearance of metabolites and xenobiotics from the colonic epithelium. On colonic biopsies from patients with and without colorectal neoplasia, molecular transport was electrophysiologically registered in Ussing-chamber set-ups, mRNA level of selected transporters was quantified by rt-PCR, and subcellular location of transporters was determined by immunohistochemistry.ResultsOf four cyclic nucleotides, dibuturyl-cAMP induced the largest short circuit current in both patient groups. The induced short circuit current was significantly lower in neoplasia-patients (p = 0.024). The observed altered transport of dibuturyl-cAMP in neoplasia-patients could not be directly translated to an observed increased mRNA expression of OATP4A1 and OATP2B1 in neoplasia patients. All other examined transporters were expressed to similar extents in both patient groups.ConclusionsOATP1C1, OATP4A1, OATP4C1 seem to be involved in the excretory system of human colon. ABCC4 is likely to be involved from an endoplasmic-Golgi complex and basolateral location in goblet cells. ABCC5 might be directly involved in the turnover of intracellular cAMP at the basolateral membrane of columnar epithelial cells, while OATP2B1 is indirectly related to the excretory system. Colorectal neoplasia is associated with lower transport or sensitivity to cyclic nucleotides and increased expression of OATP2B1 and OATP4A1 transporters, known to transport PGE2.

Relation between treatment efficacy and cumulative dose of alpha interferon in chronic hepatitis B

BACKGROUND/AIMS Alpha interferon (IFN) is an established treatment of chronic hepatitis B. The effect has been shown to be dose related, recommended dose regimens being associated with a doubling of the spontaneous, baseline HBeAg to anti-HBe seroconversion rate. However, the efficacy of IFN treatment in relation to the dose of IFN actually received remains to be established. The aim of this study was to estimate the relative efficacy of IFN as a function of the cumulative IFN dose. In addition we determined if and when a patient returns to his baseline chance of seroconversion after stopping IFN therapy. MATERIALS AND METHODS Individual patient data from 10 clinical controlled trials were available for the present analysis, in all, 746 patients, of whom 491 received IFN and 255 were untreated controls. The data were analyzed performing a time-dependent Cox regression analysis of the relative efficacy of IFN using the cumulative IFN dose administered up to any given time during the observation period and the time after termination of therapy as explanatory variables. RESULTS In the proposed model, the chance of HBeAg disappearance for a treated patient relative to no therapy was estimated to 2.1 at a cumulative dose of 100 MU and leveled out at about 2.8 at a cumulative dose of 500 MU. The effect of IFN was shown to decay rapidly after discontinuation and after 3 months a patient could be considered to be back to his baseline chance of HBeAg disappearance. These findings show that IFN administered at a dose of 15-30 MU/week should be considered effective (relative efficacy approximately 2) already after 1-2 months of treatment. CONCLUSIONS The present findings do not lend any support to the concept that IFN treatment becomes less effective when a certain total dose of IFN has been administered or that the treatment effect reaches beyond 3 months after stopping IFN.

Colonic epithelial ion transport is not affected in patients with diverticulosis

BackgroundColonic diverticular disease is a bothersome condition with an unresolved pathogenesis. It is unknown whether a neuroepithelial dysfunction is present. The aim of the study was two-fold; (1) to investigate colonic epithelial ion transport in patients with diverticulosis and (2) to adapt a miniaturized Modified Ussing Air-Suction (MUAS) chamber for colonic endoscopic biopsies.MethodsBiopsies were obtained from the sigmoid part of the colon. 86 patients were included. All patients were referred for colonoscopy on suspicion of neoplasia and they were without pathological findings at colonoscopy (controls) except for diverticulosis in 22 (D-patients). Biopsies were mounted in MUAS chambers with an exposed area of 5 mm2. Electrical responses to various stimulators and inhibitors of ion transport were investigated together with histological examination. The MUAS chamber was easy to use and reproducible data were obtained.ResultsMedian basal short circuit current (SCC) was 43.8 μA·cm-2 (0.8 – 199) for controls and 59.3 μA·cm-2 (3.0 – 177.2) for D-patients. Slope conductance was 77.0 mS·cm-2 (18.6 – 204.0) equal to 13 Ω·cm2 for controls and 96.6 mS·cm-2 (8.4 – 191.4) equal to 10.3 Ω·cm2 for D-patients. Stimulation with serotonin, theophylline, forskolin and carbachol induced increases in SCC in a range of 4.9 – 18.6 μA·cm-2, while inhibition with indomethacin, bumetanide, ouabain and amiloride decreased SCC in a range of 6.5 – 27.4 μA·cm-2, and all with no significant differences between controls and D-patients. Histological examinations showed intact epithelium and lamina propria before and after mounting for both types of patients.ConclusionWe conclude that epithelial ion transport is not significantly altered in patients with diverticulosis and that the MUAS chamber can be adapted for studies of human colonic endoscopic biopsies.