Christoph Licht

Signalling and regulation of collagen I synthesis by ET-1 and TGF-β1

Endothelin‐1 (ET‐1) plays an important role in tissue remodelling and fibrogenesis by inducing synthesis of collagen I via protein kinase C (PKC). ET‐1 signals are transduced by two receptor subtypes, the ETA‐ and ETB‐receptors which activate different Gα proteins. Here, we investigated the expression of both ET‐receptor subtypes in human primary dermal fibroblasts and demonstrated that the ETA‐receptor is the major ET‐receptor subtype expressed. To determine further signalling intermediates, we inhibited Gαi and three phospholipases. Pharmacologic inhibition of Gαi, phosphatidylcholine‐phospholipase C (PC‐PLC) and phospholipase D (PLD), but not of phospholipase Cβ, abolished the increase in collagen I by ET‐1. Inhibition of all phospholipases revealed similar effects on TGF‐β1 induced collagen I synthesis, demonstrating involvement of PC‐PLC and PLD in the signalling pathways elicited by ET‐1 and TGF‐β1. ET‐1 and TGF‐β1 each stimulated collagen I production and in an additive manner. ET‐1 further induced connective tissue growth factor (CTGF), as did TGF‐β1, however, to lower levels. While rapid and sustained CTGF induction was seen following TGF‐β1 treatment, ET‐1 increased CTGF in a biphasic manner with lower induction at 3 h and a delayed and higher induction after 5 days of permanent ET‐1 treatment. Coincidentally at 5 days of permanent ET‐1 stimulation, a switch in ET‐receptor subtype expression to the ETB‐receptor was observed. We conclude that the signalling pathways induced by ET‐1 and TGF‐β1 leading to augmented collagen I production by fibroblasts converge on a similar signalling pathway. Thereby, long‐time stimulation by ET‐1 resulted in a changed ET‐receptor subtype ratio and in a biphasic CTGF induction.

MPGN II – genetically determined by defective complement regulation?

MPGN II is a rare disease which is characterized by complement containing deposits within the GBM. The disease is characterized by functional impairment of the GBM causing progressive loss of renal function eventually resulting in end stage renal disease.It now becomes evident that in addition to C3NeF, which inhibits the inactivation of the alternative C3 convertase C3bBb, different genetically determined factors are also involved in the pathogenesis of MPGN II. These factors though different from C3NeF also result in defective complement regulation acting either through separate pathways or synergistically with C3NeF. Following the finding of MPGN II in Factor H deficient animals, patients with MPGN II were identified presenting with an activated complement system caused by Factor H deficiency. Factor H gene mutations result in a lack of plasma Factor H or in a functional defect of Factor H protein. Loss of Factor H function can also be caused by inactivating Factor H autoantibodies, C3 mutations preventing interaction between C3 and Factor H, or autoantibodies against C3. Identification of patients with MPGN II caused by defective complement control may allow treatment by replacement of the missing factor via plasma infusion, thus possibly preventing or at least delaying disease progress.

Prolonged survival in alveolar capillary dysplasia syndrome.

Survival for up to 101 days is reported in an infant with congenital alveolar capillary dysplasia (ACD) with misalignment of pulmonary veins using inhaled nitric oxide thereby offering the prospect of survival until lung transplantation can be performed. The patient was a 3040 g Caucasian girl delivered at 39 weeks gestation. She developed cyanosis, tachypnoea, and hypoxaemia at 12 h of age. Echocardiography demonstrated atrial and ductal right-to-left shunt and suprasystemic right ventricular pressure. Following evaluation of the effect of different dosages of inhaled nitric oxide (iNO) during cardiac catheterisation, the therapeutic dose was chosen to be between 2–10 ppm, with a target O2 saturation of 95%. Right ventricular pressure decreased from 90–110 mmHg before to 60–65 mmHg after starting NO inhalation. Mean systolic arterial blood pressure was 55–75 mmHg. Breathing rate ranged from 30 to 50/min. A sibling had died 5 years earlier at the age of 17 days from a similar clinical presentation and ACD had been diagnosed at autopsy. At the age of 23 days, an open lung biopsy was performed. Pulmonary lobules were abnormally developed and showed thickened immature septa. Alveolar capillaries were frequently located in a central position deep inside the septa and were rarely in contact with the alveolar epithelium. Pulmonary veins could be found within the bronchovascular bundles adjacent to the pulmonary arteries instead of their normal intra-acinar course away from the arterial branches (‘‘misalignment’’). Pulmonary arteries showed thickened muscular walls reflecting persistent pulmonary hypertension. In addition, prematurely muscularised arterioles were found within the pulmonary acini, the typical findings of ACD combined with misalignment of pulmonary veins (MPV). Pathological changes in ACD/MPV resemble a normal fetal lung at the canalicular stage and can therefore also be seen as an arrest of pulmonary development at this stage [3]. Over a period of about 3 months the infant developed normally. The child underwent evaluation for possible lung transplantation. However, starting at the age of 13 weeks, the child developed sudden attacks of oxygen desaturation whilst breathing normally. The attacks were resistant to therapy. At the age of 101 days, the child did not recover from one of these attacks. An autopsy was not performed. The course of ACD/MPV in female siblings of one mother and two different fathers is different from the inheritance pattern in the literature and eliminates a possible recessive pedigree [5]. The first child died during the neonatal period (day 17), the second, reported here in detail, after 101 days of life, both of respiratory distress and permanent pulmonary hypertension (PPHN). When the second child showed similar symptoms after delivery, and after other causes for respiratory distress and PPHN had been ruled out, ACD/MPV was assumed, and subsequently proven. To date, ACD/MPV is a fatal disease [2,6]. Progress in lung transplantation in infants during the past years offers a therapeutic option for patients with ACD/MPV. As demonstrated by our report, prolonged survival using treatment with iNO could serve as a bridge to lung transplantation [1,4]. C. Licht (&) Æ A. Vierzig Æ B. Roth Department of Paediatrics, Children s Hospital, University of Cologne, Joseph-Stelzmann-Strasse 9, 50924 Cologne, Germany E-mail: christoph.licht@uni-koeln.de Tel.: +49-221-4784391 Fax: +49-221-4785835

A stepwise approach to the treatment of early onset nephrotic syndrome.

Abstract We have retrospectively reviewed our single-center experience of the treatment of early onset nephrotic syndrome (NS). From 1991 to 1998, ten children with NS were treated. Kidney biopsy showed focal sclerosis (n=1), diffuse mesangial sclerosis (n=7), and congenital NS of the Finnish type (n=2). Associated conditions included incomplete Drash syndrome (n=1), Galloway-Mowat syndrome (n=1), and severe mental and motor retardation of unknown origin (n=3). From 1991 to 1997, five children with NS were treated. Bilateral nephrectomy (NX) was performed in three, one patient with severe retardation died at 4 years and NX was not performed in one patient who showed satisfactory growth and development. Three of these children were dialyzed and two were successfully transplanted. One patient was transplanted without previous dialysis. From 1997 to 1998, five children were treated with a regimen that included captopril and indomethacin (CAPTO/INDO). CAPTO/ INDO was successful in increasing serum protein in all patients and producing growth and development in four patients. In two patients CAPTO/INDO was successful only after unilateral NX. Our experience indicates that CAPTO/INDO may be a valuable treatment in patients with early onset NS. An individualized stepwise approach including unilateral NX should be considered to achieve optimal results.

The Mechanisms of Taurine Mediated Protection against Cell Damage Induced by Hypoxia and Reoxygenation

Taurine administered during hypoxia markedly reduced the cell damage due to O2 deficiency and reoxygenation. Different mechanisms are responsible for the improved survival of the renal cell cultures. Taurine markedly reduces the osmoregulatory deterioration during hypoxia and reoxygenation. Calcium homeostasis was markedly improved. Ca2+ efflux during hypoxia as well as Ca2+ overload during reoxygenation was significantly reduced by the amino acid. The effect of taurine was partly comparable to the effect induced by Ca2+ channel blockers. One of the effects mainly responsible for cellular protection seems to be the taurine-induced acceleration of cellular growth processes in spite of hypoxia and reoxygenation. The spectrum of cytoprotective effects of taurine predisposes this substance to be a physiological protective agent responsible for cellular homeostasis or enantiostasis.

Endogenous Distress in Ventilated Full-Term Newborns with Acute Respiratory Failure

Objective: The main rationale behind the continuous analgesia/sedation currently practiced in the treatment of neonates with severe respiratory failure in intensive care is an attempt at shielding the sick newborn from exogenous stress and pain caused by diagnostic and therapeutic interventions. Until now, however, the factors which influence endogenous, disease-related distress have been largely ignored. Method: We retrospectively studied the daily need for analgesics and sedatives (fentanyl, midazolam, pentobarbital, thiopental) of 40 full-term newborns with severe respiratory failure who had been ventilated for at least 48 h over an observational period of 2–5 days. Dosing of the analgesics and sedatives was based on a neonatal sedation score for ventilated infants. These daily amounts were converted to a normative comparative dose (analgesic/sedative need = ASN) and compared with the oxygenation index (OI) as a measure of the degree of pulmonary insufficiency. Results: Depending on the duration of ventilation, an increasingly close correlation between the ASN and the OI was detected: the index of correlation (r) was detected to be 0.65 on the second day, but increased up to 0.94 after 5 days. The subgroup of patients who had been ventilated for more than 3 days (n = 8) consistently showed a very high correlation, ranging from r = 0.86 to r = 0.94. Conclusion: Our results indicate a direct relationship between severity of pulmonary failure (expressed as OI) and degree of disease-related distress (reflected by ASN). This supports the hypothesis that in full-term neonates under mandatory intensive care for severe respiratory failure, endogenous distress caused by the primary disease itself, in addition to exogenous distress caused by therapeutic and diagnostic interventions, is key factor for the determination of the required amount of analgesic and sedative drugs.

Influence of Taurine Supplementation on Ischemic Preservation of the Isolated Rat Kidney

Taurine (2-aminoethanesulfonic acid) is an endogenous amino acid with unique functions as a modulator of transmembraneous calcium transport, an osmoregulator and putatively a free radical scavenger4,7,12.

Das Problem der verantworteten Therapieentscheidung in der Neonatologie

ZusammenfassungIn der Neonatologie—wie auch in anderen Bereichen der Intensivmedizin—müssen Ärzte und Pflegende häufig die ethisch schwierige Entscheidung treffen, ob die Therapie eines schwer kranken Patienten intensiviert oder eingeschränkt werden soll. In der Literatur existieren verschiedene Instrumente zur Entscheidungsfindung, die, angewandt im Rahmen ethischer Konsile, die Nachvollziehbarkeit einer ausgesprochenen Empfehlung gewährleisten sollen. Zwei dieser verfügbaren Modelle („Schema zur ethischen Urteilsbildung nach dem Muster der aristotelischen Ethik“, Honnefelder 1994 und die „Nimwegener Methode für ethische Fallbesprechung“, Gordijn 1998) wurden anhand klinischer Fälle auf ihre Anwendbarkeit in der Neonatologie hin untersucht. Unsere Studie zeigt, dass die Verwendung eines Entscheidungshilfeinstruments zwar grundsätzlich sinnvoll ist, deckt aber gleichzeitig den Konkretisierungsbedarf der oben genannten Modelle beim Einsatz in der Neonatologie auf. Der daraufhin entwickelte „Kölner Arbeitsbogen zur ethischen Entscheidungsfindung in der Neonatologie“ stellt ein auf die speziellen Bedürfnisse der Neonatologie ausgerichtetes Schema dar und könnte damit eine Lücke für den rasant expandierenden Bereich der Früh- und Neugeborenenmedizin schließen.AbstractDefinition of the problem: Physicians and nurses who work in neonatology—as in intensive care at all—are often forced to decide whether to stop or to continue with the treatment of a severely ill patient. The literature provides several decision making instruments, which are meant to help and to rationalize such decisions. Method and conclusion: Two of these instruments (“Schema zur ethischen Urteilsbildung nach dem Muster der aristotelischen Ethik”, Honnefelder 1994; “Nimwegener Methode für ethische Fallbesprechung”, Gordijn 1998) were tested by retrospectively examining two cases of our NICU. Results of our study show that the use of a decision making instrument is basically helpful. But the above mentioned instruments showed also shortcomings when used in the framework of neonatology. Therefore we developed the “Kölner Arbeitsbogen zur ethischen Entscheidungsfindung in der Neonatologie”, which is adapted to the specific needs of neonatology.

Posttransplant lymphoproliferative disease in a child: clinical and molecular characterization

Abstract We report a 12-year-old girl suffering from end-stage renal disease due to focal-segmental sclerosis and retardation of statomotoric and mental development of unknown origin. Renal transplantation (TX) was performed 7 months after initiation of peritoneal dialysis at the age of 11 years. Immunosuppressive therapy included cyclosporine A, mycophenolate mofetil and methylprednisolone. The patient developed spiking fever up to 40°C without signs of infection 10 months after TX. Kidney function remained stable but ultrasound examination and CT-scan showed hypodense masses within both liver and spleen. Epstein-Barr virus (EBV) polymerase chain reaction (PCR) results with a high number of copies (20×106 copies/ml blood) against the background of a previous EBV infection (IgG positive, IgM negative) made the diagnosis of EBV-reactivation likely. Splenectomy was performed. Examination of the spleen showed EBV-associated polymorphic posttransplant lymphoproliferative disease (PTLD) with predominant B cell proliferation and monoclonal VH3-rearrangement of the IgG heavy chain locus. Therapy with acyclovir was introduced and immunosuppression was reduced. No rejection episode occurred. Body temperature normalized and the patient recovered over a 3-month period. EBV-PCR in plasma was negative (0.02×106 copies/ml blood) 12 weeks after reduction of immunosuppression. The liver masses completely resolved after 27 months. After a total follow-up of 36 months the child remains in good health.