Fetal cardiac function at 35-37 weeks' gestation in pregnancies that subsequently develop pre-eclampsia

OBJECTIVE

To compare fetal cardiac morphology and function between pregnancies that subsequently developed pre-eclampsia (PE) and those that remained normotensive.

METHODS

This was a prospective observational study in 1574 pregnancies at 35-37 weeks' gestation, including 76 that subsequently developed PE. We carried out comprehensive assessment of fetal cardiac morphology and function including novel imaging modalities, such as speckle-tracking echocardiography, and measured uterine artery pulsatility index, mean arterial pressure (MAP), serum placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and cerebroplacental ratio (CPR). The findings in the group that subsequently developed PE were compared to those in pregnancies that remained normotensive.

RESULTS

In fetuses of mothers who subsequently developed PE, compared to those from normotensive pregnancies, there was a more globular right ventricle, as shown by reduced right ventricular sphericity index, reduced right ventricular systolic contractility, as shown by reduced global longitudinal strain, and reduced left ventricular diastolic function, as shown by increased E/A ratio. On multivariable regression analysis, these indices demonstrated an association with PE, independent of maternal characteristics and fetal size. In pregnancies that subsequently developed PE, compared to those that remained normotensive, MAP, sFlt-1 and the incidence of low birth weight were higher, whereas serum PlGF, CPR and the interval between assessment and delivery were lower. These findings demonstrate that, in pregnancies that develop PE, there is evidence of impaired placentation, reflected in low PlGF and reduced birth weight, placental ischemia, evidenced by increased sFlt-1 which becomes apparent in the interval of 2-4 weeks preceding the clinical onset of PE, and consequent fetal hypoxia-induced redistribution in the fetal circulation, reflected in the low CPR.

CONCLUSION

Although the etiology of the observed fetal cardiac changes in pregnancies that subsequently develop PE remains unclear, it is possible that the reduction in right-heart systolic function is the consequence of high afterload due to increased placental resistance, whilst the early left ventricular diastolic changes could be due to fetal hypoxia-induced redistribution in the fetal circulation. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Influence of birth weight on fetal cardiac indices at 35-37 weeks' gestation

OBJECTIVE

Echocardiographic studies have reported that fetuses with low birth weight, compared to those with normal birth weight, have globular hearts and reduced cardiac function. Dichotomizing continuous variables, such as birth weight, may be helpful in describing pathology in small studies but can prevent us from identifying physiological responses in relation to change in size. The aim of this study was to explore associations between fetal cardiac morphology and function and birth weight, as a continuous variable, as well as uterine artery (UtA) pulsatility index (PI), as an indirect measure of placental perfusion, and the cerebroplacental ratio (CPR), as an indirect measure of fetal oxygenation.

METHODS

This was a prospective study of 1498 women with singleton pregnancy undergoing routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation. Pregnancies complicated by pregestational or gestational diabetes mellitus, chronic hypertension, pregnancy-induced hypertension or pre-eclampsia were excluded from the analysis. Conventional and more advanced echocardiographic modalities, such as speckle tracking, were used to assess fetal cardiac function in the right and left ventricles. The morphology of the fetal heart was assessed by calculating the right and left sphericity indices. In addition, the PI of the UtA, umbilical artery (UA) and fetal middle cerebral artery (MCA) was determined and the CPR was calculated by dividing MCA-PI by UA-PI. Multiple linear regression models were used to assess determinants of fetal echocardiographic parameters.

RESULTS

The study population included 146 (9.7%) small-for-gestational-age (SGA) fetuses with birth weight < 10^th percentile and 68 (4.5%) with fetal growth restriction (FGR). In the SGA and FGR groups, compared to the non-SGA and non-FGR fetuses, respectively, there was a more globular right ventricle and reduced left and right ventricular systolic function, and, from the left ventricular diastolic functional indices, the E/A ratio was increased. There was a linear association of right ventricular sphericity index, indices of left and right ventricular systolic function and E/A ratio with birth-weight Z-score. There were no significant associations between cardiac morphological and functional indices and UtA-PI Z-score or CPR Z-score.

CONCLUSIONS

This screening study at 35-37 weeks' gestation has demonstrated that birth weight is a determinant of fetal cardiac morphology and function but UtA-PI and CPR, as indirect measures of placental perfusion and fetal oxygenation, are not. This suggests that the differences in fetal cardiac indices between small and appropriately grown fetuses may be part of a normal physiological response to change in fetal size rather than part of a pathological adaptation to abnormal placental perfusion and fetal oxygenation. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Cardiac function in gestational diabetes mellitus: A longitudinal study from fetal life to infancy

OBJECTIVE

To determine whether cardiac functional and structural changes in fetuses of mothers with gestational diabetes mellitus (GDM) persist in the offspring beyond the neonatal period.

DESIGN

Longitudinal study.

SETTING

Fetal Medicine Unit in a UK teaching hospital.

METHODS

73 women with GDM and 73 women with uncomplicated pregnancy were recruited and fetal cardiac scans were performed at 35-36 weeks' gestation. Repeat echocardiogram was performed in their offspring during infancy.

MAIN OUTCOME MEASURES

Fetal and infant cardiac functional and structural changes.

RESULTS

Fetuses of mothers with GDM, compared with controls, had more globular right ventricles (sphericity index 0.7, interquartile range [IQR] 0.6/0.7 versus 0.6, IQR 0.5/0.6, P < 0.001) and reduced right global longitudinal systolic strain (-16.4, IQR -18.9/-15.3 versus -18.5, IQR -20.6/-16.8, P = 0.001) and left global longitudinal systolic strain (-20.1, IQR -22.5/-16.9 versus -21.3, IQR -23.5/-19.5), P = 0.021). In the GDM group, compared with controls, in infancy there was higher left ventricular E/e' (8.7, IQR 7.3/9.7 versus 7.9 IQR, 6.8/8.9 P = 0.011) and lower left ventricular global longitudinal systolic strain (-21.0, IQR -22.5/-19.4 versus -22.3, IQR -23.5/-20.7, P = 0.001) and tricuspid annular plane systolic excursion (13.8, IQR 12.7/16.1 versus 15.2, IQR 13.8/16.8, P = 0.003). These differences remained following multivariable analysis.

CONCLUSION

Gestational diabetes mellitus is associated with alterations in fetal cardiac function and structure compared with controls and persistent cardiac changes in infancy.

TWEETABLE ABSTRACT

Gestational diabetes mellitus, even when well controlled, is associated with fetal cardiac changes and these persist in infancy.

Insight into the incidence of acute aortic dissection in the German region of Berlin and Brandenburg

BACKGROUND

Stanford acute type A aortic dissection (ATAAD) is a potentially lethal condition. Epidemiology studies show a statistical incidence in Europe of approximately 2-16 cases/100,000 inhabitants/year. In Germany, the estimated incidence (here subsumed under "thoracic aortic dissection" with 4.63 cases/100,000 inhabitants/year) is mainly extracted from medical death certificates by the German Federal Statistical Office. The prehospital incidence of ATAAD deaths is largely unknown. Since patients often die in the pre-hospital setting, the incidence of ATAAD is therefore likely to be higher than current estimates.

MATERIAL AND METHODS

For the period from 2010 to 2014, we retrospectively analyzed all in-hospital ATAAD data from two of the largest cardiac surgical centers that treat ATAAD in the Berlin-Brandenburg region. In addition, autopsy reports of all forensic medicine institutes and of one large pathological provider in the region were analyzed to identify additional non-hospitalized ATAAD patients. Based on these findings, the regional incidence of ATAAD was calculated.

RESULTS

In addition to in-hospital ATAAD patients (n=405), we identified additional 145 lethal ATAAD cases among 14,201 autopsy reports. The total of 550 ATAAD cases led to an estimated incidence of 11.9 cases/100,000 inhabitants/year for the whole Berlin-Brandenburg region. Arterial hypertension, pre-existing aortic dilatation, and hereditary connective tissue disorder were found in, respectively, 62.7%, 10%, and 1.8% of patients.

CONCLUSION

ATAAD is more frequent than previously reported. Our results show that when patients who die outside of cardiac surgery centers are included, the incidence of ATAAD significantly exceeds the rate reported by the Federal Statistical Office.

Medium-chain fatty acids modulate myocardial function via a cardiac odorant receptor

Several studies have demonstrated the expression of odorant receptors (OR) in various human tissues and their involvement in different physiological and pathophysiological processes. However, the functional role of ORs in the human heart is still unclear. Here, we firstly report the functional characterization of an OR in the human heart. Initial next-generation sequencing analysis revealed the OR expression pattern in the adult and fetal human heart and identified the fatty acid-sensing OR51E1 as the most highly expressed OR in both cardiac development stages. An extensive characterization of the OR51E1 ligand profile by luciferase reporter gene activation assay identified 2-ethylhexanoic acid as a receptor antagonist and various structurally related fatty acids as novel OR51E1 ligands, some of which were detected at receptor-activating concentrations in plasma and epicardial adipose tissue. Functional investigation of the endogenous receptor was carried out by Ca²⁺ imaging of human stem cell-derived cardiomyocytes. Application of OR51E1 ligands induced negative chronotropic effects that depended on activation of the OR. OR51E1 activation also provoked a negative inotropic action in cardiac trabeculae and slice preparations of human explanted ventricles. These findings indicate that OR51E1 may play a role as metabolic regulator of cardiac function.

Re-induction with L-DNR/FLAG improves response after AML relapse, but not long-term survival

BACKGROUND

According to the results of the international study Relapsed AML 2001/01 response was better after re-induction with L-DNR/FLAG (liposomal daunorubicin, fludarabine, cytarabine, G-CSF) compared to FLAG only but survival rate was not improved. However, the findings might be group-specific.

METHOD

Patient characteristics, actual therapy given and long-term course of the disease in 155 pediatric patients (including non-randomized) with first relapse and 10 primary nonresponders treated in Germany were analyzed.

RESULTS

Overall 4-year survival rates after relapse were similar in the 2 treatment groups L-DNR/FLAG and FLAG (0.43 ± 0.05 vs. 0.47 ± 0.06, p(log-rank)=0.47). The rate of randomization was low (65%) and 5% of the 101 randomized patients changed the treatment arm. Therefore, induction was based in 40% patients on an individual decision with preference for L-DNR/FLAG. There were less patients with favorable cytogenetics and morphology in the L-DNR/FLAG-group (p<0.04). Response to the first re-induction course at day 28 tended to be more unfavorable with FLAG only. In this patient group protocol intensifications were more frequent as compared to the L-DNR/FLAG-group (p=0.07), and late CR could be achieved after intensification in 9/18 poor responding patients.

CONCLUSION

The initial selection bias of relapse patients with unfavorable risk factors to the disadvantage of the L-DNR/FLAG-group and the more drug- and time-intensive treatment after 1(st) re-induction given in the FLAG-group may have nullified the initial beneficial effect of L-DNR containing re-induction therapy and led to similar and relatively favorable survival rates in both treatment groups in Germany.

[Antisense oligonucleotides for therapy of cystic fibrosis. Inhibition of sodium absorption mediated by ENaC in nasal epithelial cells]

BACKGROUND

The genetic disease cystic fibrosis (CF) is characterised by reduced chloride secretion mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) and Na(+) hyperabsorption through amiloride-sensitive epithelial sodium channels (ENaC). Mutations in CFTR cause the accumulation of thick mucus and dysfunction of mucociliary clearance in the respiratory tract.

MATERIAL AND METHODS

In this project it was investigated whether Na(+) hyperabsorption is inhibited by the use of antisense oligonucleotides (AON). For functional analyses monolayers of human non-CF and CF nasal epithelial cells were measured in modified Ussing chambers. To analyse the AON effects on the protein level Western blotting analyses were carried out.

RESULTS

AON transfection significantly inhibits Na(+) absorption via ENaC in non-CF and CF cells. Furthermore, Western blot analyses demonstrate a suppression of the ENaC protein in AON transfected human non-CF cells.

CONCLUSION

The inhibition of ENaC associated Na(+) absorption by specific AON could offer a new perspective for the regulation of the Na(+) hyperabsorption in CF patients.

Gene expression of the key enzymes of melatonin synthesis in extrapineal tissues of the rat

Besides the pineal gland, melatonin is reported to be produced in a number of extrapineal sites, where it could act as an intracellular mediator or paracrine signal in addition to its endocrine effects. In view of the suggested immunoregulatory role of melatonin, we compared lymphoid organs and several other tissues of the rat for their potential to synthesize melatonin. Using the reverse transcription-polymerase chain reaction (RT-PCR) method, we determined the tissue-specific expression of mRNAs encoding two key enzymes of the melatonin biosynthesis: serotonin-N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT). The minimal number of PCR cycles required to obtain a positive signal served as a measure for the abundance of a given mRNA. NAT and HIOMT mRNAs were detected in all tested tissues at high numbers of PCR cycles (40 and 45, respectively). At 35 cycles, only gut, testis, spinal cord, raphe nuclei, stomach fundus and striatum yielded positive signals for both enzymes. In conclusion, the presence of NAT and HIOMT mRNAs in a wide range of tissues corroborates and extends the notion of extrapineal melatonin synthesis. Comparatively low levels of the HIOMT messages in lymphoid organs, however, indicate a limited significance of melatonin synthesis within the immune system.

The effect of hyperglycaemia on cerebral potentials evoked by rapid rectal distension in healthy humans

BACKGROUND

Acute hyperglycaemia affects the perception of sensations arising from the gastrointestinal tract. The mechanisms responsible for this effect are unknown. Recordings of cerebral evoked potentials (EPs) can be used to assess the integrity of visceral afferent pathways. Our aim was to determine whether hyperglycaemia affects EPs elicited by rectal distension in healthy humans.

MATERIALS AND METHODS

Twelve healthy men, aged 19-31 years, were studied. A manometric catheter, incorporating a rectal balloon, was positioned 7-10 cm from the anal verge. Balloon distensions at both 'low' ( approximately 20 mL) and 'high' ( approximately 28 mL) volumes were performed, in a single-blind, randomized order, during both euglycaemia (4 mmol L-1) and hyperglycaemia (12 mmol L-1). EPs were recorded from a midline scalp electrode (Cz, International 10-20 system) and averaged for each series of 50 distensions. EP latencies and interpeak amplitudes were calculated.

RESULTS

Polyphasic EPs were recorded in all but one subject. Although the blood glucose concentration had no significant effect on the latencies of the EP peaks elicited by either 'low'- or 'high'-volume balloon distension, the interpeak amplitude (P1-N1) was greater during hyperglycaemia than during euglycaemia at the 'low' balloon volume (6.3 +/- 1.2 microV vs. 4.8 +/- 1.0 microV, P < 0.05). The blood glucose concentration had no significant effect on the perception of rectal balloon distension.

CONCLUSIONS

We conclude that in normal subjects acute hyperglycaemia increases the amplitude of the cerebral EP elicited by rectal balloon distension at low balloon volumes, suggesting that the effects of hyperglycaemia on gastrointestinal sensation may be mediated by central mechanisms.

Voluntary movement after pallidotomy in severe Parkinson's disease

The mechanisms of improvement in parkinsonian bradykinesia after posteroventral pallidotomy were investigated in 17 patients undergoing unilateral pallidotomy for severe Parkinson's disease. Clinical ratings of 'off' period bradykinesia demonstrated a maximal improvement of 22% 3 months postoperatively. Kinematic assessments of rapid repetitive finger and sequential arm movements were performed after overnight withdrawal of antiparkinsonian medications. There was a bilateral reduction in the inter-onset latency of a two-stage sequential arm movement and a contralateral increase in speed of arm movement after pallidotomy. There was no significant improvement postoperatively in the rhythm, amplitude or speed of repetitive finger movements. The results confirm the clinical impression that pallidotomy improves bradykinesia. This was more evident for complex limb movements, which used attentional strategies and external (visual and auditory) cues, than for repetitive fingertapping movements, which were largely internally generated. Since ablation of the pallidum can only reduce inhibitory pallidal outflow, it is unlikely to restore the normal pallidal influence on thalamocortical motor circuits. Therefore, any improvement in bradykinesia after pallidotomy must be related to mechanisms other than restoration of pallidothalamocortical connectivity. Based on the above observations, we suggest that some of the changes in motor control may be explained by the greater efficacy of external cues in facilitating movement after withdrawal of the abnormal pallidal discharge.

Effects of hyperglycemia on cortical response to esophageal distension in normal subjects

Acute changes in the blood glucose concentration affect the intensity of gastrointestinal sensations. The aim of this study was to examine the effects of hyperglycemia on cortical potentials evoked by esophageal distension. In 16 healthy volunteers, a balloon was positioned in the lower esophagus. A series of 50 distensions was performed at both a lower volume (producing definite sensation) and a higher volume (producing unpleasant sensation), at blood glucose concentrations of 5 and 13 mmol/liter. Triphasic cortical potentials were recorded from a midline scalp electrode (Cz). During euglycemia, interpeak amplitudes were greater at the higher than the lower balloon volume (P < 0.005). At the lower balloon volume, the interpeak amplitudes were greater during hyperglycemia than euglycemia (P < 0.05). There was no effect of the blood glucose concentration on amplitude at the higher balloon volume. We conclude that in healthy subjects, the amplitude of the cortical response to moderate, but not unpleasant, esophageal distension is greater during hyperglycemia when compared to euglycemia. These observations are consistent with the concept of increased intensity of gut sensation during hyperglycemia.

Apolipoprotein E e4 allele in the normal elderly: neuropsychologic and brain MRI correlates

The presence of the apolipoprotein E e4 allele has been considered to be a risk factor for Alzheimer's disease and vascular dementia. We therefore used demanding neuropsychologic testing and brain MRI to determine if elderly normals with at least one e4 allele demonstrate subclinical changes in cognition and a higher frequency of brain atrophy or silent ischemic brain damage. The study population consisted of 214 randomly selected individuals aged 50 to 75 years without neuropsychiatric or general disease. There were 175 (81.8%) subjects without and 39 (18.2%) with at least one e4 allele. The two groups were comparable for age, length of education, verbal intelligence, mood and major vascular risk factors. Apolipoprotein E e4 carriers performed significantly worse than non-carriers when assessed for learning and memory abilities, while there were no differences in test results of conceptualization, attention, speed of mental processing and visuopractical skills. There were no between-group differences for thromboembolic and lacunar infarcts, white matter hyperintensity grading and the semiautomatically measured white matter hyperintensity area. The extent of sulcal and ventricular widening as well as hippocampal and parahippocampal volumes were also similar between the comparative subsets. We conclude that the apolipoprotein E e4 allele is associated with subtle learning and memory deficits in normal elderly persons and may therefore be suggested a marker for accelerated cognitive aging. In this group of subjects it was not associated with brain parenchymal changes as demonstrated by MRI.

Radioimmunoassays for cyclic AMP cross-react with phosphodiesterase inhibitors and buffer components

We addressed the issue of cross-reactivity of several commonly used phosphodiesterase inhibitors with radioimmunoassays for cyclic AMP, after we had observed a considerably high cross-reactivity with a noncommercial antibody. Theophylline, pentoxifylline, penthydroxifylline (BL 194), albifylline (HWA 138), torbafylline (HWA 448), A 80 2715, isobutyl methylxanthine, and the nonmethylxanthines amrinone and rolipram were dissolved in supplemented and boiled cell culture medium (RPMI 1640). These samples were assayed for apparent cyclic AMP in two different, commercially available radioimmunoassay kits (based on polyclonal antibodies), applying the nonacetylated protocol. Cross-reactivity was dose-dependent and nonlinear. Samples containing theophylline and amrinone exhibited the strongest cross-reactivity in assay A (NEN/DuPont): 3.0 +/- 0.5(-nM) and 2.4 +/- 1.1 (-nM) apparent cyclic AMP +/- SD at 1-nM spike, respectively. With the more sensitive assay B (Amersham), higher concentrations of apparent cyclic AMP were detected: from 7.9 +/- 0.4 nM (for albifylline) to 3.5 +/- 0.1 nM (for rolipram). Values were calculated from standard curves set up in the respective assay buffer, where culture medium controls resulted in 1.8 +/- 0.3 nM and 3.1 +/- 0.1 nM for assay A and B, respectively. The culture medium interference increased with rising cyclic AMP concentrations. Although comparatively low, this degree of cross-reactivity is relevant for in vitro experiments. Phosphodiesterase inhibitors are commonly administered at millimolar concentrations, and resulting cyclic AMP levels are often in the nanomolar range. Neglecting these findings may lead to falsely high readouts of cyclic AMP concentrations.

Enhanced tumor necrosis factor suppression and cyclic adenosine monophosphate accumulation by combination of phosphodiesterase inhibitors and prostanoids

We investigated cooperative effects of phosphodiesterase (PDE) inhibitors and prostanoids on cyclic adenosine monophosphate (cAMP) accumulation and tumor necrosis factor (TNF)-alpha synthesis in human peripheral blood mononuclear cells (PBMC). PDE inhibitors alone induced only a small increase in cAMP levels in lipopolysaccharide (LPS)-stimulated PBMC. Cicaprost (a stable analogue of prostacyclin) and pentoxifylline added simultaneously to LPS-stimulated PBMC (2.0 x 10(6)/ml) induced a rapid increase of cAMP to a level of 100 nM that peaked within 10 min and remained at a plateau for up to 4 h. Thus combined prostanoids and PDE inhibitors enhanced cAMP accumulation. TNF-alpha suppression in the presence of pentoxifylline and prostanoids exceeded that of either drug alone. The potency of different PDE inhibitors (theophylline, pentoxifylline, penthydroxifylline, albifylline, torbafylline, A 80 2715, amrinone and rolipram) to increase cAMP levels in combination with cicaprost was evaluated after 1 h of incubation. The dose-dependent increase of cAMP for all PDE inhibitors tested in this combined stimulation provided a useful tool for evaluating the potency of PDE inhibitors on cAMP accumulation. The effective concentration of PDE inhibitors, which raised cAMP levels to 300% of control, (EC300), correlated with the IC50 for TNF-alpha suppression (r = 0.930, p = 0.007, with theophylline excluded from the analysis). Interestingly, by contrast, the specific type IV PDE inhibitor rolipram caused only a moderate rise of accumulated cAMP in the same cells. Our data support cAMP as an essential mediator for TNF-alpha suppression by PDE inhibitors. Furthermore, an enhanced inhibiting effect on TNF-alpha production may prove therapeutically advantageous. It may occur in inflammatory and infectious diseases in vivo, since high levels of endogenous prostaglandins are liberated in these conditions.

Prostacyclin analogs suppress the synthesis of tumor necrosis factor-alpha in LPS-stimulated human peripheral blood mononuclear cells

Recent reports have shown that prostaglandin E2 (PGE2) is able to suppress lipopolysaccharide (LPS)-stimulated production of tumor necrosis factor-alpha (TNF-alpha). In the present study we compared PGE2 with prostacyclin (PGI2) analogs in their potency to influence LPS-stimulated production of interleukin-1 beta (IL-1 beta) and TNF-alpha by human mononuclear cells (MNC). Our results show, that the stable analogs of PGI2, iloprost and cicaprost, markedly suppress TNF-alpha synthesis in LPS-stimulated MNC without effect on IL-1 beta production. Although there was no significant difference in maximal suppression of TNF-alpha, iloprost and cicaprost reached suppression to 50% of control at 20-fold lower concentrations than PGE2. The ID50 for iloprost and cicaprost were 8 nM and 5 nM, respectively, compared to 125 nM for PGE2. Moreover, the prostacyclin analogs as well as PGE2 suppressed LPS-induced production of TNF-alpha in Mono Mac 6 cells, a permanent human cell line with characteristics of mature monocytes. Suppression of TNF-alpha synthesis by cicaprost and PGE2 is probably mediated by an increased intracellular cAMP formation. We were able to show elevated cAMP levels with 1 microM and 10 microM of PGE2 and cicaprost in this system. The suppression of TNF-alpha synthesis may add to the beneficial effects of iloprost reported in animal models of acute respiratory distress syndrome (ARDS) and may offer a therapeutic approach in TNF-alpha mediated pathologic processes.

The specific type IV phosphodiesterase inhibitor rolipram suppresses tumor necrosis factor-alpha production by human mononuclear cells

Compounds suppressing the production of tumor necrosis factor-alpha are protective in animal models of septic shock. Recent studies demonstrated a beneficial effect of xanthine derivatives, which suppress tumor necrosis factor-alpha production by acting as non-specific cAMP phosphodiesterase inhibitors. In this experiment we tested the effect of (+/-)-rolipram (racemate) and its enantiomers on human mononuclear cells stimulated with lipopolysaccharide (LPS). Rolipram has a phenyl-pyrrolidinone structure, unrelated to the methylxanthines, and acts as a specific inhibitor of the type IV phosphodiesterase. Our results identify rolipram as a remarkably potent suppressor of the LPS-induced synthesis of tumor necrosis factor-alpha. When compared to the non-specific inhibitor pentoxifylline, the IC50 of (+/-)-rolipram (130 nM) is more than 500 times lower. The influence of rolipram on tumor necrosis factor-alpha production depended on the steric configuration of the molecule, since the (-)-enantiomer exhibited a five times lower IC50 than the (+)-enantiomer. The inhibitory effect of all substances tested is selective for tumor necrosis factor-alpha rather than interleukin-1 beta, since interleukin-1 beta production is only slightly influenced.

Xanthine derivatives: comparison between suppression of tumour necrosis factor-alpha production and inhibition of cAMP phosphodiesterase activity

Several in vitro and in vivo studies have demonstrated suppression of tumour necrosis factor-alpha (TNF-alpha) synthesis by pentoxifylline. In the present study we compared the effect of pentoxifylline with that of five other xanthine derivatives. We addressed two questions. First, what is the relative potency of those chemically related compounds in suppressing the lipopolysaccharide (LPS)-induced production of TNF-alpha in human mononuclear cells? Second, does suppression of TNF-alpha production by these xanthine derivatives correlate with their capacity to inhibit 3',5'-cAMP phosphodiesterase (PDE) activity? The experimental drug A 80 2715 [1-(5-hydroxy-5-methylhexyl)-3-methyl-7-propylxanthine] was identified as the most potent agent with an IC50 (concentration exerting 50% suppression of LPS-induced TNF-alpha production) of 41 microM (mean of 13 individuals). The IC50 values of the other substances ranged between 106 microM for HWA 138 and 419 microM for theophylline. The LPS-induced interleukin-1 beta (IL-1 beta) production was not influenced by all substances tested at comparable concentrations. Inhibition of PDE activity was determined in a cell-free system using PDE isolated from bovine heart. All xanthine derivatives dose-dependently inhibited PDE activity. Furthermore, with the exception of theophylline, there was a high degree of correlation between the potency to suppress TNF-alpha production in the cell culture system and the potency to inhibit PDE activity in the cell-free enzymatic assay. This argues for a crucial role of PDE inhibition in the suppression of TNF-alpha synthesis by xanthine derivatives.