Frank Bidlingmaier

Surgical stress induces a shift in the type-1/type-2 T-helper cell balance, suggesting down-regulation of cell-mediated and up-regulation of antibody-mediated immunity commensurate to the trauma*

BACKGROUNDnMeasuring serum cytokines, pituitary hormones, or acute phase proteins during or after surgery is not an optimal method for quantifying the impact of surgical procedures. In an effort to assess surgical stress by means of the immune response, we focused on changes in cell-mediated and antibody-mediated immunity as illustrated by the type 1/type 2 T-helper (Th1/Th2) cell balance. The sensitivity of this approach was evaluated by comparing laparoscopic and conventional cholecystectomy (LCE, CCE).nnnMETHODSnIn a pragmatic prospective study 43 patients with symptomatic cholelithiasis were operated on either by LCE (n = 25) or CCe (n = 18). Blood sampling was done 24 hours before surgery, immediately before incision, and 2, 24, and 48 hours after surgery. Cell surface markers and cytokine production were used to characterize the Th1/Th2 balance and were measured by means of flow cytometry and enzyme-linked immunosorbent assay techniques.nnnRESULTSnActivation of Th2 cells evokes the production and secretion of interleukin-4 (IL-4), which up-regulates the expression of immunoglobulin E receptors (Fo epsilon RII, CD23) on B cells. Phytohemagglutinin-induced IL-4 production in freshly isolated peripheral blood mononuclear cells from patients increased more after CCE than LCE (IL-4, +41% versus +17%; p < 0.05). Also the expression of CD23 on B cells was higher after CCE than LCE (+146% versus +63%; P < 0.01). CD30, a membrane molecule that belongs to the tumor necrosis factor receptor superfamily and probably is an important indicator of Th2 activity, was more evaluated on T cells from patients who underwent CCE. The Th1 response, characterized by phytohemagglutinin-induced IFN-gamma secretion in peripheral blood mononuclear cells and up-regulation of human leukocyte antigen-DR expression on monocytes, was lower after CCE than after LCE.nnnCONCLUSIONSnThis study shows that surgical stress induces a shift in the Th1/Th2 balance toward Th2, suggesting that cell-mediated immunity is down-regulated and antibody-mediated immunity is up-regulated after surgery. The evaluation of this shift may be clinically meaningful and help quantify even less invasive surgical procedures. When comparing CCE and LCE in this not strictly randomized study, we found LCE to be the less stressful procedure.

Expression of CYP19 (aromatase) mRNA in different areas of the human brain.

The conversion of androgens to estrogens by CYP19 (cytochrome P450AROM, aromatase) is an important step in the mechanism of androgen action in the brain. CYP19 expression has been demonstrated in the brain of various animal species and in the human temporal lobe. Studies on postnatal CYP19 expression in various other areas of the human brain are rare and carried out in a limited number of post mortem obtained tissue. Therefore, we investigated CYP19 mRNA expression in fresh human frontal and hippocampal tissues and compared them to the expression in temporal neocortex tissues. We studied biopsy materials removed at neurosurgery from 45 women and 54 men with epilepsy. Quantification of CYP19 mRNA was achieved by nested competitive reverse transcription-PCR. CYP19 mRNA concentrations were significantly higher in temporal (2.29+/-0.40 arbitrary units, AU, mean +/- SEM; n = 57) than in frontal neocortex specimens (0.92+/-0.17 AU; n = 18; P<0.04). In hippocampal tissue specimens CYP19 expression (1.41+/-0.18 AU; n = 24) was lower than in temporal neocortex specimens, but the difference did not reach statistical significance. Sex differences were not observed in any of the brain regions under investigation. In conclusion, CYP19 mRNA is expressed in the human temporal and frontal neocortex as well as in the hippocampus. Regardless of sex, CYP19 expression was significantly higher in the temporal than in the frontal neocortex.

Neuroactive steroids and seizure susceptibility

There is increasing clinical and experimental evidence that hormones, in particular sex steroid hormones, influence neuronal excitability and other brain functions. The term neuroactive steroids has been coined for steroids that interact with neurotransmitter receptors. One of the best characterized actions of neuroactive steroids is the allosteric modulation of GABA(A)-receptor function via binding to a putative steroid-binding site. Since neuroactive steroids may interact with a variety of other membrane receptors, excitatory as well as inhibitory, they may have an impact on the excitability of specific brain regions. Neuronal excitability is enhanced by estrogen, whereas progesterone and its metabolites exert anticonvulsant effects. Testosterone and corticosteroids have less consistent effects on seizure susceptibility. Apart from these particular properties, neuroactive steroids may regulate gene expression via progesterone receptors. Based on their molecular properties, these compounds appear to have a promising therapeutical profile for the treatment of different neuropsychiatric diseases including epilepsy. This review focuses on the effects of neuroactive steroids on neuronal excitability and their putative impact on the physiology of epileptic disorders.

Androgen receptor mRNA expression in the human hippocampus.

The androgen receptor (AR) plays a central role in mediating androgen action. Since the hippocampus is a target of steroid modulation, we studied the expression of AR mRNAs in hippocampal tissue specimens from patients undergoing epilepsy surgery (n=42). AR mRNA expression was in the same order of magnitude than in prostate tissue, known for its high expression of AR. AR mRNA concentrations showed no significant difference in AR mRNA expression between men (49.3+/-8.0 arbitrary units (aU); mean+/-SEM) and women (54.3+/-11.2 aU) and no sex-specific hippocampal lateralization pattern was observed. No relationship could be detected between duration of epilepsy, individual seizure frequency, age of the patients and the expression levels of AR. The high expression of AR in the hippocampus suggests that this human brain area is an important target for androgen action.

Protein kinase C involvement in lipid peroxidation and cell membrane damage induced by oxygen-based radicals in hepatocytes.

We investigated the effects of oxygen-based radicals induced by t-butyl hydroperoxide or H2O2/Cu2+ on cultured hepatocytes. Radical exposure caused membrane lesions (blebs), lactate dehydrogenase release and lipid peroxidation (i.e. formation of malondialdehyde) in cells. As expected, radical scavengers (catalase, alpha-tocopherol) strongly inhibited these phenomena. A similar or even superior inhibitory effect was achieved by the protein kinase C (PKC) inhibitors H-7 and phloretin. These agents did not reveal notable radical scavenging properties as assessed by their ability to break down H2O2. The PKC stimulators 4 beta-phorbol-12-myristate-13 and 1-olyeoyl-2-acetyl-sn-glycerol intensified the detrimental actions of the radical-inducing agents. [3H]Phorbol-12,13-dibutyrate-binding studies showed that membrane association of PKC is markedly increased in hepatocytes after exposure to H2O2/Cu2+ or t-butyl hydroperoxide. These results suggest that PKC membrane translocation and activation may be important for mediating membrane damage and lipid peroxidation after cells are exposed to oxygen-based radicals.

A novel stable polyalanine [poly(A)] expansion in the HOXA13 gene associated with hand-foot-genital syndrome: proper function of poly(A)-harbouring transcription factors depends on a critical repeat length?

Abstract. Hand-foot-genital syndrome (HFGS) is a dominantly inherited congenital malformation affecting the distal limbs and genitourinary tract. Here, we describe the phenotype and its molecular basis in a family that presented with HFGS. Genetic analysis revealed that the condition is caused by an 18-bp in-frame duplication within a cryptic trinucleotide repeat sequence encoding an 18-residue polyalanine tract in the homeobox gene (HOX) A13. This mutation expands the stretch with six extra alanine residues. Similar types of mutation (plus eight alanines) have recently been found in another HFGS family and also in the human HOXD13 gene (plus seven up to plus 14 residues) where it leads to synpolydactyly (SPD), a further congenital limb malformation rarely associated with genital abnormalities. As observed in our family, all the expanded tracts encoding polyalanine, either reported for HOXA13 or HOXD13, are quite stable when transmitted within affected families. Unlike disorders with unstable expansions of perfect trinucleotide repeats the molecular mechanism underlying these polyalanine expansions should be unequal crossing-over rather than replication slippage. The alanine tract elongation may prevent protein-protein interactions of the mutant HOXA13, thereby inducing a localized heterochrony in the sequence of distal limb and genitourinary development.

FEMALE PSEUDOHERMAPHRODITISM ASSOCIATED WITH A NOVEL HOMOZYGOUS G-TO-A (V370-TO-M) SUBSTITUTION IN THE P-450 AROMATASE GENE

The conversion of C19 androgens to their corresponding C18 estrogens is catalyzed by an enzyme complex known as aromatase. P-450 aromatase is expressed in a tissue-specific manner and placental deficiency abolishes its function in protecting the female fetus from masculinization and the mother from prepartum virilization due to an excess of androgens. Here we report a novel homozygous aromatase mutation (Val370-to-Met) found in a girl with pseudohermaphroditism (Prader V). Sequence analysis showed the parents to be heterozygous for this amino acid substitution. Since P-450arom deficiency is a rare autosomally recessive transmitted disease, consanguinity in this kindred seemed to be obvious. With the characterization of four intragenic polymorphisms and subsequent haplotype analysis this assumption turned out to be most likely.

Expression of 5α-Reductase and 3α-Hydroxisteroid Oxidoreductase in the Hippocampus of Patients with Chronic Temporal Lobe Epilepsy

Summary: Purpose: The hippocampus is one of the principal target areas for neurosteroidal action, and the major neuroen‐docrine conversion of progesterone appears to be 5α‐reduction and 3α‐hydroxysteroid oxidoreduction, leading to the potent neurosteroid 3α,5α‐tetrahydroxyprogesterone. To investigate whether the human hippocampus is equipped with the enzymes 5α‐reductase and 3α‐hydroxysteroid oxidoreductase (3α‐HSOR), we studied the expression of 5α‐reductase types 1 and 2 and 3α‐HSOR types 1 and 2 in the resected hippocampi of patients with medically intractable chronic temporal lobe epilepsy.

A comparison of different methods for diagnosing acromegaly

OBJECTIVEThe present study was designed to assess the diagnostic value of different single measurements in comparison to the classic time‐consuming method, the oral glucose tolerance test (OGTT), in acromegaly.

Allopregnanolone serum levels and expression of 5α-reductase and 3α-hydroxysteroid dehydrogenase isoforms in hippocampal and temporal cortex of patients with epilepsy

In the human central nervous system, progesterone is rapidly metabolised to 5α-dihydroprogesterone which subsequently is further reduced to allopregnanolone (AP). These conversions are catalysed by 5α-reductase and 3α-hydroxysteroid dehydrogenase (3α-HSD). Although different isoforms of both enzymes have been identified in the brain, our knowledge of their expression in the human brain remains limited. The aim of the present study was to investigate the mRNA expression of 5α-reductase 1 as well as 3α-HSD 1, 2, 3 and 20α-HSD in brain tissue from patients with pharmacoresistant temporal lobe epilepsy (TLE). Specimens were derived from either the hippocampus or the temporal lobe cortex and from the tumor-free approach corridor tissue of patients with brain tumors. Quantification of different mRNAs was achieved by real time PCR. In addition, we provide data on simultaneous evaluation of serum AP concentrations. We could demonstrate that 3α-HSD 1 was not expressed in the hippocampus and temporal lobe of patients with TLE. In the hippocampus and temporal lobe, the expression levels of 3α-HSD 2 were about 20% of that in liver tissue, those of 3α-HSD 3 about 7% and those of 20α-HSD about 2%, respectively. In patients with TLE, expression of 3α-HSD 2 was significantly higher in the hippocampus than in temporal lobe cortex tissue (P<0.006). AP concentrations did not correlate significantly with the mRNA expression levels of 5α-reductase 1, 3α-HSD 2 and 3 and 20α-HSD in any of the patient groups under investigation. In conclusion, the present study demonstrates mRNA expression of 5α-reductase 1 and 3α-HSD 2 and 3 and 20α-HSD in the hippocampus and temporal lobe of epileptic patients. These findings provide further molecular biological evidence for the formation and metabolism of neuroactive steroids in the human brain.