Diagnosis of rare entity CD138 negative plasma cell multiple myeloma: the synergy between laboratory and clinician makes the difference

Plasma cell multiple myeloma (MM) is a multiform clinical entity characterized by different laboratory hallmarks. This case shows a rare entity of plasma cell myeloma: the entire plasma cell population lack the CD138 expression. In this case, a careful analysis of laboratory finding, particular flow cytometry gating strategies and the use of other ancillary laboratory tests, guide the clinicians to correct diagnosis. The correct evaluation of pre-analytical phase and the correct gating strategy are the necessary conditions to produce robust and solid flow cytometric results. The diagnostic implications of CD138-negative plasma cell are strictly linked to stem cell-like clonogenic features, such as possible more aggressive clinical behaviour and increasing probability of chemotherapy resistance. At this time, clinical laboratory remains the main reference point to MM diagnosis.

Long pentraxin 3 as a marker of COVID-19 severity: evidences and perspectives

Introduction

Materials and methods

Results

Conclusion

Antigen Reactivity and Clinical Significance of Autoantibodies Directed Against the Pyruvate Dehydrogenase Antigen Complex in Patients With Connective Tissue Disease

Introduction

Antimitochondrial antibodies (AMAs) are the hallmark of primary biliary cholangitis (PBC) but can be identified also in patients with connective tissue disease, namely, systemic sclerosis (SSc). Protein immunoprecipitation (IP) and IP-Western blot (WB) can be used to confirm AMA positivity directed at the pyruvate dehydrogenase complex (PDC) subunits E1α, E1β, E2/E3, and E3BP in patients showing a cytoplasmic reticular pattern at indirect immunofluorescence when performed in a screening setting before the onset of overt cholestasis in rheumatic patients.

Patients and Methods

We studied sera from 285 patients affected by connective tissue disease [SSc, n = 144; dermato/polymyositis (DM/PM), n = 56; and undifferentiated connective tissue disease (UCTD), n = 85] by indirect immunofluorescence (IIF), protein-IP, and IP-WB to identify specific PDC subunits recognized by AMA.

Results

Twenty percent (57/285) of sera from patients with connective tissue disease had a cytoplasmic reticular pattern at IIF, and in 77% (44/57, including 20 SSc, 12 PM/DM, and 12 UCTD) of these, we detected different titers of autoantibodies against the PDC subunits, specifically against PDC-E2. Among these sera, 4 (9%) tested positive for anti-E1α, 15 (34%) for anti-E1β, and 16 (36%) for anti-E3BP. Four of the 20 AMA-positive SSc cases (20%) had been already diagnosed with PBC, and all were positive for autoantibodies against the subunits PDC-E2, E3, and E3BP.

Conclusions

Using IIF and IP, we confirm that autoantibodies against the PDC components are detected in rheumatic patients with PBC or without liver dysfunction. In view of the strong predictive value of AMA for PBC, a strict follow-up of these latter patients is warranted for an early diagnosis of the disease.

Acute severe autoimmune hepatitis with anti-rods and rings autoantibodies; literature first evidence

Autoimmune hepatitis (AIH) was defined as a progressive, chronic inflammatory autoimmune liver disease (ALD). The diagnosis of AIH requires the presence of characteristic clinical and laboratory features, and the exclusion of other clinical conditions that cause chronic hepatitis and cirrhosis. AIH can have an acute onset that mimics an acute viral or toxic hepatitis or an acute severe (fulminant, ASF) presentation that satisfies criteria for acute liver. Guidelines from the European Association for the Study of Liver Diseases define ALF with absence of pre-existing liver disease, acute onset of ≤ 26 weeks, coagulopathy (international normalised ratio (INR) ≥ 1.5), and presence of hepatic encephalopathy (HE). In recent years, autoantibodies (Aab) targeting subcellular structures described as the rods and rings (R&R) pattern in HEp-2 ANA have been presented as a unique and particular case of Aab generation. These R&R structures are composed of inosine monophosphate dehydrogenase type 2 (IMPDH2), and their formation can be induced in vitro by several small-molecule inhibitors. Aab targeting these relatively unknown structures has been observed in Hepatitis C virus (HCV) patients who have undergone treatment with pegylated interferona/ ribavirin (IFN/RBV) therapy. We presented and characterized a case patient with R&R and SMA Aab in AIH (ASF, fatal, without liver transplantation). To the best of our knowledge, this is the first evidence described in the Literature. Our early experience showed the R&R circulating Aab in one patient with Primary Biliary Cholangitis. This work now demonstrates that R&R Aab can also be present in AIH case.

Syncope at SARS-CoV-2 onset

We describe clinical and laboratory findings in 35 patients tested positive for SARS-CoV-2 by reverse transcriptase-polymerase chain reaction on nasopharyngeal swab experiencing one or multiple syncope at disease onset. Clinical neurologic and cardiologic examination, and electrocardiographic findings were normal. Chest computed tomography showed findings consistent with interstitial pneumonia. Arterial blood gas analysis showed low pO2, pCO2, and ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2) indicating hypocapnic hypoxemia. Patients who presented with syncope showed significantly lower heart rate as compared to 68 SARS-CoV-2 positive that did not. Such poorer than expected compensatory heart rate increase may have led to syncope based on individual susceptibility. We speculate that SARS-CoV-2 could have caused angiotensin-converting enzyme-2 (ACE2) receptor internalization in the nucleus of the solitary tract and other midbrain nuclei, impairing baroreflex and chemoreceptor response, and inhibiting the compensatory tachycardia during acute hypocapnic hypoxemia.

Laboratory markers included in the Corona Score can identify false negative results on COVID-19 RT-PCR in the emergency room

After December 2019 outbreak in China, the novel Coronavirus infection (COVID-19) has very quickly overflowed worldwide. Infection causes a clinical syndrome encompassing a wide range of clinical features, from asymptomatic or oligosymptomatic course to acute respiratory distress and death. In a very recent work we preliminarily observed that several laboratory tests have been shown as characteristically altered in COVID-19. We aimed to use the Corona score, a validated point-based algorithm to predict the likelihood of COVID-19 infection in patients presenting at the Emergency rooms. This approach combines chest images-relative score and several laboratory parameters to classify emergency room patients. Corona score accuracy was satisfactory, increasing the detection of positive patients' rate.

Laboratory Biomarkers Predicting COVID-19 Severity in the Emergency Room

Infection of novel Coronavirus has been declared pandemic by the WHO and now is a world public health crisis. Laboratory activity becames essential for the timely diagnosis. Few parameters, such Lymphocytes count, SaO2 and CRP serum level can be used to assess the severity of COVID-19 in emergency room.

AB0051 SERUM AMYLOID A AND PENTRAXIN 3: INNATE IMMUNE RESPONSE AND DISEASE ACTIVITY IN SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Systemic Lupus Erythematosus (SLE) is an autoimmune disease that involves several molecular patterns with a wide spectrum of clinical manifestations and symptoms. Inflammation and related pathway play a role in SLE pathogenesis. The pentraxin superfamily including long and short pentraxin, C Reactive Protein CRP, Serum amyloid A (SAA), Pentraxin 3 (PTX3) are key components of innate immune system and induce a variety of inflammation associated pathway. However Literature provides several evidences that CRP serum levels not correlated with clinical and immunological manifestations. This situation affected clinical practice and the patient follow up. PTX3 have been identified as a component of inflammatory status in several autoimmune conditions. SAA is an acute phase protein secreted in large quantity during inflammation.

Objectives:

We want to evaluated SAA, PTX3 and CRP concentrations, their correlation between SLE Disease Activity Index (SLEDAI), that including complement fractions C3, C4.

Methods:

We enrolled fifty patients that fulfilled the SLE American College of Rheumatology criteria and fifty healthy subjects. The SLE disease activity was classified with the SLEDAI (0 to 12). Patients were divided into two groups according to SLEDAI score: inactive group (Group 1, 25 patients, 50%: SLEDAI < 4) and active group (Group 2, 25 patients, 50%: SLEDAI 5 to 12). PTX3 concentration was measured by a sandwich ELISA kit (Hycult) with 2.8 ng/mL cut-off point. SAA concentration was detected by nephelometry performed on a BN ProSpec System (Siemens, Germany), with assay kit based on polyclonal antibodies (Siemens Healthcare Diagnostics Products, Germany, 6.5 mg/L cut-off point). High sensitive CRP concentrations were determined using the ci8200 platform (Abbott Laboratories Chicago, Illinois).

Results:

Plasma PTX3 and serum SAA levels was significantly higher in SLE patients than in the healthy subjects (PTX311.5 ± 7.3 ng/mL vs 2.3 ± 1.1; p < 0.001; SAA: 87 ±77 mg/L vs 2.6±2.5; p < 0.001). These differences were not evident in CRP levels (8.5 ± 7.8 mg/L vs 6.2± 2.5). Considering two groups, there were statistical differences in PTX3 level (Group 2: 14.9 ± 12 ng/mL vs Group 1: 2.16 ±0.5 ng/mL, p<0,05) and SAA concentration (Group 2: 114 ± 89 ng/mL vs Group 1: 3.6 ±1.7 ng/mL, p<0,05) but not in CRP concentration (Group 2: 11.5 ± 8.4 mg/L vs Group 1: 9.5 ±3.5). There was a significantly negative correlation between C3, C4 fractions, PTX3 and SSA levels (respectively r = −0.74, p=<0.05, and r = −0.79, p<0.05). No statistical correlation were appeared between C3, C4 fractions and CRP serum levels (r= −0,12., p= 0.82, and r= −0.18, p= 0,21). We noted a positive significant correlation between SLEDAI, PTX3 and SAA concentration (r = 0.79, p < 0.05, 0.83, p < 0.05, respectively) an increase in PTX3 and SAA levels followed the lupus flare and symptoms. No significant correlation appeared between SLEDAI and CRP (r= 0.15, p=0.89)

Conclusion:

PTX3 and SAA concentration was significantly higher in SLE patients than the healthy control subjects and their levels reflected disease activity. We showed a direct correlation between PTX3 and SAA. In SLE patients PTX3 and SAA concentrations were correlated with SLEDAI. We suggest an integrate viewpoint in witch SAA and PTX3 may play a role as a biomarker of disease activity, with synergic work during SLE events. Evidences suggested that PTX3 and SAA could trigger the same molecular pathway, by TLR4, via NF-kB.

References:

[1]Assandri R, Monari M Montanelli A. Pentraxin 3 in Systemic Lupus Erithematosus: Questions to be Resolved, Translational Biomedicine (2015)

Disclosure of Interests:

None declared

Modified Corona Score can easily identify Covid-19 patients with gastrointestinal symptoms: An Italian proposal

AIM

We propose the Modified Corona Score (MCorona score), an alternative approach to identifying new likely Covid-19 patients without positive chest images, but with gastrointestinal onset.

BACKGROUND

In April, 2020, a total of 104,291 laboratory-confirmed cases had been documented in Italy; Lombardy, the Northern Italian Region, recorded over 60,000 Covid-19 cases.

METHOD

The MCorona score is built by several laboratory parameters linked between age and gender, ranging from 0 to 10.

RESULTS

Using the preliminary score cut-off of 4, we successfully identified likely Covid-19 patients with gastrointestinal onset. However, more caution is needed, and a larger sample size is required to verify the accuracy and specificity of the score.

CONCLUSION

We propose the complete validation of the MCorona score, an instrument able to diagnose likely Covid-19 patients with symptoms other than respiratory distress.

Primary biliary cholangitis with contemporary presence of anti-mithocondrial and anti-rods and rings autoantibodies: literature first case

Primary biliary cholangitis, previously known as primary biliary cirrhosis (PBC), is the most common autoimmune diseases of the liver (ALD). Patients with PBC may present with typical biliary pattern symptoms. Also the presence of anti-mitochondrial autoantibodies (AMAs) is the laboratory hallmark of PBC, which molecular target antigens are members of 2-oxoacid dehydrogenase complex of enzymes. In recent years, autoantibodies (Aab) targeting subcellular structures described as the rods and rings (R&R) pattern in HEp-2 ANA have been presented as a unique and particular case of Aab generation. These R&R structures are composed of inosine monophosphate dehydrogenase type 2 (IMPDH2), and their formation can be induced in vitro by several small-molecule inhibitors. Aab targeting these relatively unknown structures have been almost exclusively observed in hepatitis C virus (HCV) patients who have undergone treatment with pegylated interferon-a/ribavirin (IFN/RBV) therapy. Literature showed that anti-RR Aab have not been found in no treatment-naïve HCV patients or in patients from any other disease. Now we present and characterized a case patient with contemporary presence of AMAs and R&R Aab in PBC, without any laboratory evidence of HCV and/or other hepatic virus infection. For our knowledge, this is the first case described in the Literature. R&R Aab in patients without any clinical/laboratory signs or symptoms of Hepatitis virus and without pharmacological therapy open the window to the alternative scenario: the association of these Aab to ALD. Our work demonstrated that R&R Aab can be present in PBC case. The interesting idea suggested that R&R Aab may be present also in AMA-negative PBC and they can considered a new possible diagnostic tool in this specific clinical condition. Other study and cases are needed but the presence of R&R Aab linked with AMAs and PBC may be explained by alterations in immune regulation caused by autoimmunity in a particular genetic background.

Diagnosis of gluten-related enteropathy in a newborn: how and when?

AIM

To analyze the development of gliadin-specific immune responses in children with a genetic risk for CD and to determine whether these could be detected before the clinical onset of the disease by using immunological tests.

BACKGROUND

Clinical manifestations of celiac disease (CD) in the first year of life is uncommon, which is due to the suboptimal sensitivity of tissue transglutaminase IgA antibodies (tTG-IgA) at this age and other possible causes of malabsorption in infants. The development of Deamidate gliadin peptide-specific antibodies (in particular DGP-IgG) in young children was poorly considered in the CD diagnosis.

METHODS

We conducted a retrospective cross-sectional study on children between one month and forty-eight months of life, which performed in our health center from 2016 to 2018. Three hundred and fifty children were selected according to strict inclusion criteria: positive for HLA-DQA1 and DQB1 alleles, positive anti tTG-IgA/IgG and/or positive DGP-IgG/IgA. Eighty-two children were selected and divided into two different groups of patients: Group one (forty newborns under twenty-four months of life) and Group two (children from twenty-five months to 48 months of life).

RESULTS

Anti-DGP-IgG antibodies precede anti tTG-IgA seroconversion in children under two years in 80% of cases. Anti-DGP-IgG positive patients had milder symptomatic forms of CD than anti tTG-IgA positive children, characterized by gastrointestinal symptoms in the presence of normal growth, normal serum iron, and low MCH level. At tTG-IgA seroconversion, children present gastrointestinal clinical forms associated with impaired growth. The combined use of tTG-IgA and DGP-IgG antibodies upgrade the diagnostic sensitivity from 50% to 92%.

CONCLUSION

Anti-DGP-IgG antibodies precede tTG-IgA seroconversion in newborns and identified two distinct clinical phenotypes. At this point, if you wanted to test your newborn patients for CD serology, how would you proceed?

Pentraxin 3 and biopsy status in celiac patients

AIM

In our study we explored a possible relationship between PTX3 and CD.

BACKGROUND

Gluten sensitivity is known as a hallmark of celiac disease (CD). The diagnosis of CD requires demonstration of a typical enteropathy, and positive serology supports the diagnosis. The CD immune response involves the adaptive, as well as the innate immunity and is characterized by the presence of anti-gliadin (AGA) and anti-transglutaminase 2 antibodies (tTGA), lymphocytic infiltration in the intestinal epithelial membrane and expression of multiple cytokines. The long pentraxin 3 (PTX3), an acute-phase inflammatory molecule, plays an important role in innate immunity.

METHODS

108 CD patients were divided according to Marsh Histological grade following Marsh criteria classification in three groups: Group 1: Marsh 0, patients with a known history of CD under gluten free diet, complete remission; Group 2: Marsh1 and Marsh 2; Group 3: Marsh 3. Healthy age-matched controls without a known history of CD or gastrointestinal symptoms (n=30) served as controls. PTX3 serum levels were measured by sandwich ELISA on an automated platform.

RESULTS

PTX3 serum levels were significantly elevated in group 3 and group 2 compared with HC (mean 3.31± 1.27 ng/mL and 3.97 ± 0.54 ng/mL versus 1.06 ± 0.59 ng/mL; P < 0.005), with group 1 (0.76±0.31 ng/mL). No statistically significant differences were found between group 1 and HC group. We found a strong linear correlation between PTX3 serum levels and AGA levels in group 2 (r=0.78, P <0.0001), and group 3 (r =0.63, P < 0.005) but no correlations were detected between PTX3 serum levels and tTGA levels (group 2, r= 0.04; group 3, r=0.24). Serological data revealed that PTX3 correlated with major gastrointestinal damage patients.

CONCLUSION

PTX3 is a component of the humoral arm of the innate immune system. Our data showed that PTX3 serum levels were high in active disease patients with pathological levels of AGA. We also demonstrated that patients with normal AGA IgA levels had PTX3 serum levels compared to healthy control. We hypothesized that PTX3 is able to modulate the innate response to gliadin in CD and it could regulate the adaptive immune response.

Development of PBC/SSc overlap syndrome in chronic GVHD patient: immunological implications in the presence of mitochondrial, nucleolar and spindle midzone autoantigens

Chronic Graft versus Host Disease (cGVHD) is a complex disease resulting from donor T-cell recognition of a genetically disparate recipient that is unable to reject donor cells after allogeneic Stem Cell Transplantation (HSCT). cGVHD has some features resembling to autoimmune diseases (AD) such as Sjögren syndrome, primary biliary cirrhosis (PBC) and scleroderma (SSc). Also patients with cGVHD could develop extensive cGVHD with scleroderma-like skin manifestations and other clinical signs similar to those of patients with scleroderma. We take into consideration a patient with GVHD that developed PBC/SSc overlap syndrome with a complex and particular autoantibodies profile. Indirect immunofluorescence (IIF) with double coloration showed a cytoplasmic mitochondrial-like pattern, a clumpy nucleolar staining pattern, and a cell-cycle related staining pattern. Following anaphase onset, proteins regulator of cytokinesis localizes to the overlap zone on the ends of midzone microtubules and becomes compacted during furrow ingression to form the midbody. Second level tests confirmed the presence of anti-mitochondrial antibodies M2-subunit but no other autoantibodies were found. We performed a home-made immunoblot analysis that identified a 37 kDa fibrillarin band, and not identify 47 kDa, 31KDa and 18/20 kDa bands. After literature review of these possible cellular localizations, the proteins recognized by our patient's serum seem likely to be Aab to core midzone organizer components. However, due to the unavailability of the proper techniques in our laboratory, we were not able to further characterize them. The pathogenesis and morbidity of cGVHD after HSCT remains enigmatic, but the presence of specific autoantibodies are the hallmark of AD and represent a possibility of differential diagnosis. Standard techniques combined with the use of non-routinely laboratory techniques are a usefully and complementary method for studying difficult and particular cases. In fact, these autoantibodies will be considered as ''diagnostic'' and not as ''esoteric'' antibodies. In conclusion, a re-assessment of the diagnostic protocols in cGVHD together with a precise observation of the clinical and laboratory picture will ultimately help us clarify the disease and could provide a better understanding of the immune network deregulation.

Elevations of inflammatory markers PTX3 and sST2 after resuscitation from cardiac arrest are associated with multiple organ dysfunction syndrome and early death

BACKGROUND

A systemic inflammatory response is observed after cardiopulmonary resuscitation. We investigated two novel inflammatory markers, pentraxin 3 (PTX3) and soluble suppression of tumorigenicity 2 (sST2), in comparison with the classic high-sensitivity C-reactive protein (hsCRP), for prediction of early multiple organ dysfunction syndrome (MODS), early death, and long-term outcome after out-of-hospital cardiac arrest.

METHODS

PTX3, sST2, and hsCRP were assayed at ICU admission and 48 h later in 278 patients. MODS was defined as the 24 h non-neurological Sequential Organ Failure Assessment (SOFA) score ≥ 12. Intensive care unit (ICU) death and 12-month Cerebral Performance Category (CPC) were evaluated.

RESULTS

In total, 82% of patients survived to ICU discharge and 48% had favorable neurological outcome at 1 year (CPC 1 or 2). At ICU admission, median plasma levels of hsCRP (2.8 mg/L) were normal, while levels of PTX3 (19.1 ng/mL) and sST2 (117 ng/mL) were markedly elevated. PTX3 and sST2 were higher in patients who developed MODS (p<0.0001). Admission levels of PTX3 and sST2 were also higher in patients who died in ICU and in those with an unfavorable 12-month neurological outcome (p<0.01). Admission levels of PTX3 and sST2 were independently associated with subsequent MODS [OR: 1.717 (1.221-2.414) and 1.340, (1.001-1.792), respectively] and with ICU death [OR: 1.536 (1.078-2.187) and 1.452 (1.064-1.981), respectively]. At 48 h, only sST2 and hsCRP were independently associated with ICU death.

CONCLUSIONS

Higher plasma levels of PTX3 and sST2, but not of hsCRP, at ICU admission were associated with higher risk of MODS and early death.

Development of systemic sclerosis in patients with autoimmune hepatitis: an emerging overlap syndrome

AIM

We described two case reports of AIH/SSc overlap syndrome and reviewed literatures regarding this issue.

BACKGROUND

AIH is a chronic hepatitis of unknown aetiology characterized by continuing hepatocellular necrosis and inflammation. AIH overlap syndromes have been reported with other autoimmune diseases.

PATIENTS AND METHODS

According to the classification criteria for SSc, we conducted a retrospective chart review of 35 cases with biopsy-proven AIH over the past 5 years at our institution. We reviewed the MEDLINE database using the appropriate key-words.

RESULTS

A chart review of 35 cases (M/F ratio 1:2, mean age 47.6±10.3 years) revealed nine patients (9/35, 25.7%) with CTD (four males and three females with a mean age of 45.1±8.4 years). All patients had ANA. Four patients were SSA/Ro positive UCTD (1/35, 2.85%), and six patients developed SLE (6/35, 17.1%). Only two female patients (2/35, 5.7%) with specific SSc AAb developed a systemic sclerosis. We described a patient with AIH who was diagnosed with diffuse systemic sclerosis-sine scleroderma with positive anti-centromere B and SSA/Ro52 KDa antibodies. We also reported a patient with AIH who was diagnosed limited SSc with contemporary presence of anti-centromere A and anti-RNA polymerase III antibody.

CONCLUSION

We suggest that SSc may be considered to be one of the manifestations associated with AIH. Patients with AIH may have an increased risk to develop SSc and should be followed, especially when Raynaud phenomenon was found.

Pentraxin 3 serum levels in celiac patients: evidences and perspectives

Celiac disease (CD) is now considered, more than a just gluten sensitivity enteropathy, a multiple and systemic immune-mediate disorder triggered by the ingestion of wheat gluten and related proteins. Following the discovery of a link between gluten and CD, it was demonstrated that gliadin, one of the two principal protein groups comprising gluten, plays a key role in CD. It has since become clear that the different and crucial roles of gliadin in CD result from its ability to activate multiple signaling pathways that modulate CD pathology. Most of these pathways involve the host innate and adaptive immune responses, but some pathways are activated when gliadin interacts with the intestinal cellular compartment. The long pentraxin (PTX3), a marker of the acute-phase inflammatory response, plays an important role in innate immunity and in modulation of the adaptive immune response. We investigated whether CD patients, considered as a model of gluten-sensitivity condition, have increased PTX3 levels. Our data showed that PTX3 serum levels were high in active CD patients and serum levels of PTX3 correlated with DGP IgA levels. We provide evidences that the bad compliance of GFD in patients 2 concurred with a pathological PTX3 concentration that could follow the improvement of both gastrointestinal and extraintestinal symptoms. We hypothesized that PTX3 is able to modulate the innate response to gliadin in CD and it could regulate the adaptive immune response. It is also evidenced that a common "wooden horse" of CD and Non Celiac Gluten Sensitivity (NCGS) is the ingestion of gluten and related toxic peptides. At the moment we don't have adequate elements to suggest the use of PTX3 in diagnosis of NCGS, but we are obliged to speculate about the possible role of PTX3 molecules in NCGS pathogenesis. The identified new strategies and uses of PTX3 could improve the management of gluten sensitivity conditions in the next future.

[Anti-Golgi antibodies: let me look around]

The new biotechnologies will be available a large number of diagnostic datas.The study of clinical cases with antibodies-anti-Golgi provides an opportunity to discuss the role of traditional approach by indirect immunofluorescence investigation.The strong collaboration between clinician and laboratory is the only possibility for a real progress.

Gastrointestinal transit and 5-ASA release from a new mesalazine extended-release formulation

BACKGROUND

Mesalazine (5-aminosalicylic acid, 5-ASA)-containing formulations represent a cornerstone in the treatment of inflammatory bowel diseases. Recently, a new formulation has been developed to provide selective and more homogeneous release of 5-ASA compared to traditional systems.

METHODS

In a first study, gastrointestinal transit was followed by gamma-scintigraphy after single-dose application of tablets containing 1200 mg mesalazine to 12 healthy male volunteers. 5-ASA release was verified by the assessment of plasma pharmacokinetics. In a second, 7-day, multiple-dose study, the steady state plasma pharmacokinetics, urinary excretion and safety profile were characterized after twice-daily tablet administration to 12 healthy volunteers.

RESULTS

Tablet erosion started after 6.9 +/- 1.1 h in the ascending or transverse colon. Radioactivity spread homogeneously throughout the colon, indicating the sustained release of active 5-ASA. Plasma kinetics indicated an earlier initial absorption of 5-ASA, i.e. during transit of the small intestine and ileum. Mean Cmax values (350.6 +/- 322.6 ng/mL) were observed during location in the ileo-caecal region. The mean relative absorption of 5-ASA was 19.9 +/- 18.2% in the small intestine and ileum and 80.1 +/- 18.2% in the colon.

CONCLUSIONS

The administration of the new mesalazine formulation was well tolerated, and 5-ASA was continuously released along the whole colon, a favourable prerequisite for the therapy of distally located inflammatory bowel disease.

Contribution of the alpha1-GABA(A) receptor subtype to the pharmacological actions of benzodiazepine site inverse agonists

A histidine-to-arginine point-mutation at position 101 in the alpha1-subunit of gamma-aminobutyric acid (GABA)(A) receptors has been shown to switch the in vitro efficacy of Ro 15-4513 from inverse agonism to agonism. In order to assess the consequences of this pharmacological switch in vivo, the motor and proconvulsant effects of Ro 15-4513 were analyzed in knock-in mice containing point-mutated alpha1(H101R)-GABA(A) receptors. Furthermore the influence of the alpha1(H101R) substitution on the efficacy of the beta-carboline inverse agonist DMCM was examined both in vitro and in vivo. Ro 15-4513 (10 mg/kg) increased baseline locomotion and potentiated the convulsant effect of pentylenetetrazole in wild type mice. In alpha1(H101R) mice, Ro 15-4513 decreased locomotion and, at a higher dose (30 mg/kg) it displayed an anticonvulsant action. In vitro, DMCM acted as an inverse agonist at recombinant alpha1beta2gamma2 receptors whereas it potentiated GABA-evoked chloride currents at alpha1(H101R)beta2gamma2 receptors. DMCM was inactive as a convulsant in alpha1(H101R) mice. In keeping with the major contribution of these receptors to the sedative and anticonvulsant properties of benzodiazepine site agonists, the present findings identify the alpha1-GABA(A) receptors as the molecular targets for the allosteric modulation by benzodiazepine site ligands in either direction with regard to the behavioral outputs, sedation/motor stimulation and anticonvulsion/proconvulsion.

Erythropoietin modulates intracellular calcium in a human neuroblastoma cell line

1. Recent investigations have shown that the glycoprotein erythropoietin (Epo) and its specific receptor (EpoR) are present in the mammalian brain including human, monkey and mouse. These findings suggest a local action of Epo in the nervous system. The aim of this study was to elucidate a possible functional interaction of Epo with neuronal cells. 2. To examine the influence of externally applied Epo on Ca2+ homeostasis the human neuroblastoma cell line SK-N-MC was chosen as a suitable in vitro model for undifferentiated neuronal cells. 3. Expression of the EpoR in SK-N-MC cells was detected by reverse transcription-PCR, Western blot and immunofluorescence analysis. 4. Patch-clamp studies of SK-N-MC cells confirmed the expression of T-type Ca2+ channels, whose peak macroscopic current was increased by the addition of recombinant human Epo (rhEpo) to the bathing medium. 5. Confocal laser scanning microscopy analysis of SK-N-MC cells confirmed a transient increase in intracellular free [Ca2+] in response to externally applied rhEpo. 6. The transient response to Epo was dependent on external Ca2+ and remained even after depletion of internal Ca2+ stores by caffeine or thapsigargin. However, after depletion the response to Epo was absent when cells were superfused with the T-type Ca2+ channel blocker flunarizine. 7. This study demonstrates that Epo can interact with neuronal cells by affecting Ca2+ homeostasis through an increase in Ca2+ influx via plasma membrane T-type voltage-dependent Ca2+ channels.

Ras pathway activates epithelial Na+ channel and decreases its surface expression in Xenopus oocytes

The small G protein K-Ras2A is rapidly induced by aldosterone in A6 epithelia. In these Xenopus sodium reabsorbing cells, aldosterone rapidly activates preexisting epithelial Na+ channels (XENaC) via a transcriptionally mediated mechanism. In the Xenopus oocytes expression system, we tested whether the K-Ras2A pathway impacts on XENaC activity by expressing XENaC alone or together with XK-Ras2A rendered constitutively active (XK-Ras2AG12V). As a second control, XENaC-expressing oocytes were treated with progesterone, a sex steroid that induces maturation of the oocytes similarly to activated Ras. Progesterone or XK-Ras2AG12V led to oocyte maturation characterized by a decrease in surface area and endogenous Na+ pump function. In both conditions, the surface expression of exogenous XENaC's was also decreased; however, in comparison with progesterone-treated oocytes, XK-ras2AG12V-coinjected oocytes expressed a fivefold higher XENaC-mediated macroscopic Na+ current that was as high as that of control oocytes. Thus, the Na+ current per surface-expressed XENaC was increased by XK-Ras2AG12V. The chemical driving force for Na+ influx was not changed, suggesting that XK-Ras2AG12V increased the mean activity of XENaCs at the oocyte surface. These observations raise the possibility that XK-Ras2A, which is the first regulatory protein known to be transcriptionally induced by aldosterone, could play a role in the control of XENaC function in aldosterone target cells.

Ionic permeability on isolated mouse liver nuclei: influence of ATP and Ca2+

Patch-clamp experiments on isolated nuclei revealed the existence of ionic channels on the nuclear envelope, but their exact localization and function are still unknown. Recent studies have demonstrated that ATP and calcium ions play an important role in nucleocytoplasmic protein traffic. ATP is essential to allow big molecules in and out of the nucleus. However, a cytoplasmic rise of calcium ions above 300 nm decreases both ATP-dependent transport and passive diffusion through the nuclear envelope. The use of isolated nuclei placed in a saline solution provides the possibility for testing only the compounds added in the bath or in the recording pipette. In the present study, we show that ATP is responsible for an increase of nuclear ionic permeability on isolated nuclei. This result not only confirms data previously reported in in situ nuclei, but also suggests that ATP is directly involved in the modulation of passive ionic permeability. In these particular experimental conditions, calcium ions decrease the channel current starting from a concentration of 1 microM. The parallelism in the modulation action of ATP and Ca++ between nuclear pores and ionic channels present on the nuclear envelope contributes to the support of the idea that an ionic pathway is associated with the pore complex.

Cytoskeletal control of rectification and expression of four substates in cardiac inward rectifier K+ channels

Cardiac inward rectifiers may have a three-barrel channel structure, based on evidence for three substates in single-channel recordings. However, some reports indicate four substates, a feature more compatible with the four-subunit structure for which there is evidence in cloned voltage-activated K+ channels. Here we show that although the fourth is easily missed, inward rectifier channels have four substates whose expression is controlled by intracellular Ca(2+) ions. Fourth substate openings also appear after rectification loss in intracellular divalent caution-free solution. We find that this process is accelerated by cytochalasin, a microfilament disrupter. Cytochalasin also abolishes Ca(2+), but not Mg(2+),-induced rectification by restoring fourth substate openings. Thus, cytoskeletal elements control Ca(2+)-dependent substate expression and rectification in native inwardly rectifying K+ channels.