Erythrocyte invasion-neutralising antibodies prevent Plasmodium falciparum RH5 from binding to basigin-containing membrane protein complexes.

Basigin is an essential host receptor for invasion of Plasmodium falciparum into human erythrocytes, interacting with parasite surface protein PfRH5. PfRH5 is a leading blood-stage malaria vaccine candidate and a target of growth-inhibitory antibodies. Here, we show that erythrocyte basigin is exclusively found in one of two macromolecular complexes, bound either to plasma membrane Ca2+-ATPase 1/4 (PMCA1/4) or to monocarboxylate transporter 1 (MCT1). PfRH5 binds to each of these complexes with a higher affinity than to isolated basigin ectodomain, making it likely that these are the physiological targets of PfRH5. PMCA-mediated Ca2+ export is not affected by PfRH5, making it unlikely that this is the mechanism underlying changes in calcium flux at the interface between an erythrocyte and the invading parasite. However, our studies rationalise the function of the most effective growth-inhibitory antibodies targeting PfRH5. While these antibodies do not reduce the binding of PfRH5 to monomeric basigin, they do reduce its binding to basigin-PMCA and basigin-MCT complexes. This indicates that the most effective PfRH5-targeting antibodies inhibit growth by sterically blocking the essential interaction of PfRH5 with basigin in its physiological context.

Essential Thrombocythemia: One-Center Data in a Changing Disease.

Introduction: Essential thrombocythemia is a chronic myeloproliferative neoplasm associated with thrombo-hemorrhagic events and the progression to myelofibrosis or acute myeloid leukemia. The purpose of this article is to present real-world data on ET cases diagnosed and managed between 1998 and 2020 in the largest, tertiary hematology reference center in Romania and to evaluate the impact of thrombotic events on survival. Methods: A real-world, retrospective cohort-type study was conducted. We collected and statistically analyzed data from 168 patients who met the 2016 WHO diagnostic criteria for ET and who were managed between 1998 and 2020 in our center. Results: The median age at diagnosis of ET was 51.8 years, with a female predominance (66.07%). The JAK2V617F mutation was detected in 60.71% of patients. Leukocytosis at diagnosis was associated with a higher risk of thrombosis, and JAK2V617F-positive cases exhibited a 1.5-fold higher risk of developing thrombotic events. The average survival in ET with major thrombosis was 14.5 years versus 20.6 years in ET cases without major thrombosis. Other predictors of survival were high-risk IPSET score and age >60 years. Conclusions: Romanian patients diagnosed with ET are generally younger than 60 years and are predominantly female. The occurrence of thrombotic events was influenced by gender, leukocyte count at diagnosis and JAK2V617F positivity. Survival was impacted by age, the presence of JAK2V617F mutation, hypertension, major thrombotic complications and IPSET score. Notably, these findings warrant careful interpretation and further confirmation in the setting of prospective studies.

A pharmacological master key mechanism that unlocks the selectivity filter gate in K+ channels.

Potassium (K+) channels have been evolutionarily tuned for activation by diverse biological stimuli, and pharmacological activation is thought to target these specific gating mechanisms. Here we report a class of negatively charged activators (NCAs) that bypass the specific mechanisms but act as master keys to open K+ channels gated at their selectivity filter (SF), including many two-pore domain K+ (K2P) channels, voltage-gated hERG (human ether-à-go-go-related gene) channels and calcium (Ca2+)-activated big-conductance potassium (BK)-type channels. Functional analysis, x-ray crystallography, and molecular dynamics simulations revealed that the NCAs bind to similar sites below the SF, increase pore and SF K+ occupancy, and open the filter gate. These results uncover an unrecognized polypharmacology among K+ channel activators and highlight a filter gating machinery that is conserved across different families of K+ channels with implications for rational drug design.

Neuroplastin and Basigin Are Essential Auxiliary Subunits of Plasma Membrane Ca2+-ATPases and Key Regulators of Ca2+ Clearance.

Plasma membrane Ca2+-ATPases (PMCAs), a family of P-type ATPases, extrude Ca2+ ions from the cytosol to the extracellular space and are considered to be key regulators of Ca2+ signaling. Here we show by functional proteomics that native PMCAs are heteromeric complexes that are assembled from two pore-forming PMCA1-4 subunits and two of the single-span membrane proteins, either neuroplastin or basigin. Contribution of the two Ig domain-containing proteins varies among different types of cells and along postnatal development. Complex formation of neuroplastin or basigin with PMCAs1-4 occurs in the endoplasmic reticulum and is obligatory for stability of the PMCA proteins and for delivery of PMCA complexes to the surface membrane. Knockout and (over)-expression of both neuroplastin and basigin profoundly affect the time course of PMCA-mediated Ca2+ transport, as well as submembraneous Ca2+ concentrations under steady-state conditions. Together, these results establish neuroplastin and basigin as obligatory auxiliary subunits of native PMCAs and key regulators of intracellular Ca2+ concentration.

Identification of Cav2-PKCß and Cav2-NOS1 complexes as entities for ultrafast electrochemical coupling.

Voltage-activated calcium (Cav) channels couple intracellular signaling pathways to membrane potential by providing Ca2+ ions as second messengers at sufficiently high concentrations to modulate effector proteins located in the intimate vicinity of those channels. Here we show that protein kinase Cß (PKCß) and brain nitric oxide synthase (NOS1), both identified by proteomic analysis as constituents of the protein nano-environment of Cav2 channels in the brain, directly coassemble with Cav2.2 channels upon heterologous coexpression. Within Cav2.2-PKCß and Cav2.2-NOS1 complexes voltage-triggered Ca2+ influx through the Cav channels reliably initiates enzymatic activity within milliseconds. Using BKCa channels as target sensors for nitric oxide and protein phosphorylation together with high concentrations of Ca2+ buffers showed that the complex-mediated Ca2+ signaling occurs in local signaling domains at the plasma membrane. Our results establish Cav2-enzyme complexes as molecular entities for fast electrochemical coupling that reliably convert brief membrane depolarization into precisely timed intracellular signaling events in the mammalian brain.

Gα(q/11) signaling tonically modulates nociceptor function and contributes to activity-dependent sensitization.

Peripheral injury or inflammation leads to a release of mediators capable of binding to a variety of ion channels and receptors. Among these are the 7-transmembrane receptors (G protein-coupled receptors) coupling to G(s), G(i/o), G12/13, or G(q/11) G proteins. Each of the G protein-coupled receptor pathways is involved in nociceptive modulation and pain processing, but the relative contribution of individual signaling pathways in vivo has not yet been worked out. The G(q)/G11 signaling branch is of particular interest because it leads to the activation of phospholipase C-ß, protein kinase C, the release of calcium from intracellular stores, and it modulates extracellular regulated kinases. To investigate the contribution of the entire G(q/11)-signaling pathway in nociceptors towards regulation of pain, we generated double-deficient mice lacking G(q/11) selectively in nociceptors using a conditional gene-targeting approach. We observed that nociceptor-specific loss of G(q) and G11 results in reduced pain hypersensitivity following paw inflammation or spared nerve injury. Surprisingly, our behavioral and electrophysiological experiments also indicated defects in basal mechanical sensitivity in G(q/11) mutant mice, suggesting a novel function for G(q/11) in tonic modulation of acute nociception. Patch-clamp recordings revealed changes in voltage-dependent tetrodotoxin-resistant and tetrodotoxin-sensitive sodium channels in nociceptors upon a loss of G(q/11), whereas potassium currents remained unchanged. Our results indicate that the functional role of the G(q)/G11 branch of G-protein signaling in nociceptors in vivo not only spans sensitization mechanisms in pathological pain states, but is also operational in tonic modulation of basal nociception and acute pain.

Oncostatin M induces heat hypersensitivity by gp130-dependent sensitization of TRPV1 in sensory neurons.

Oncostatin M (OSM) is a member of the interleukin-6 cytokine family and regulates eg. gene activation, cell survival, proliferation and differentiation. OSM binds to a receptor complex consisting of the ubiquitously expressed signal transducer gp130 and the ligand binding OSM receptor subunit, which is expressed on a specific subset of primary afferent neurons. In the present study, the effect of OSM on heat nociception was investigated in nociceptor-specific gp130 knock-out (SNS-gp130-/-) and gp130 floxed (gp130fl/fl) mice.Subcutaneous injection of pathophysiologically relevant concentrations of OSM into the hind-paw of C57BL6J wild type mice significantly reduced paw withdrawal latencies to heat stimulation. In contrast to gp130fl/fl mice, OSM did not induce heat hypersensitivity in vivo in SNS-gp130-/- mice. OSM applied at the receptive fields of sensory neurons in in vitro skin-nerve preparations showed that OSM significantly increased the discharge rate during a standard ramp-shaped heat stimulus. The capsaicin- and heat-sensitive ion channel TRPV1, expressed on a subpopulation of nociceptive neurons, has been shown to play an important role in inflammation-induced heat hypersensitivity. Stimulation of cultured dorsal root ganglion neurons with OSM resulted in potentiation of capsaicin induced ionic currents. In line with these recordings, mice with a null mutation of the TRPV1 gene did not show any signs of OSM-induced heat hypersensitivity in vivo.The present data suggest that OSM induces thermal hypersensitivity by directly sensitizing nociceptors via OSMR-gp130 receptor mediated potentiation of TRPV1.

Genetic evidence for an essential role of neuronally expressed IL-6 signal transducer gp130 in the induction and maintenance of experimentally induced mechanical hypersensitivity in vivo and in vitro.

Tenderness and mechanical allodynia are key symptoms of malignant tumor, inflammation and neuropathy. The proinflammatory cytokine interleukin-6 (IL-6) is causally involved in all three pathologies. IL-6 not only regulates innate immunity and inflammation but also causes nociceptor sensitization and hyperalgesia. In general and in most cell types including immune cells and sensory neurons, IL-6 binds soluble µ receptor subunits which heteromerizes with membrane bound IL-6 signal transducer gp130. In the present study, we used a conditional knock-out strategy to investigate the importance of signal transducer gp130 expressed in C nociceptors for the generation and maintenance of mechanical hypersensitivity. Nociceptors were sensitized to mechanical stimuli by experimental tumor and this nociceptor sensitization was preserved at later stages of the pathology in control mice. However, in mice with a conditional deletion of gp130 in Nav1.8 expressing nociceptors mechanical hypersensitivity by experimental tumor, nerve injury or inflammation recovery was not preserved in the maintenance phase and nociceptors exhibited normal mechanical thresholds comparable to untreated mice. Together, the results argue for IL-6 signal transducer gp130 as an essential prerequisite in nociceptors for long-term mechanical hypersensitivity associated with cancer, inflammation and nerve injury.

Genetic evidence for involvement of neuronally expressed S1P1 receptor in nociceptor sensitization and inflammatory pain.

Sphingosine-1-phosphate (S1P) is a key regulator of immune response. Immune cells, epithelia and blood cells generate high levels of S1P in inflamed tissue. However, it is not known if S1P acts on the endings of nociceptive neurons, thereby contributing to the generation of inflammatory pain. We found that the S1P1 receptor for S1P is expressed in subpopulations of sensory neurons including nociceptors. Both S1P and agonists at the S1P1 receptor induced hypersensitivity to noxious thermal stimulation in vitro and in vivo. S1P-induced hypersensitivity was strongly attenuated in mice lacking TRPV1 channels. S1P and inflammation-induced hypersensitivity was significantly reduced in mice with a conditional nociceptor-specific deletion of the S1P1 receptor. Our data show that neuronally expressed S1P1 receptors play a significant role in regulating nociceptor function and that S1P/S1P1 signaling may be a key player in the onset of thermal hypersensitivity and hyperalgesia associated with inflammation.

Inhibitor kappaB Kinase beta deficiency in primary nociceptive neurons increases TRP channel sensitivity.

Inhibitor kappaB kinase (IKK) regulates the activity of the transcription factor nuclear factor-kappa B that normally protects neurons against excitotoxicity. Constitutively active IKK is enriched at axon initial segments and nodes of Ranvier (NR). We used mice with a Cre-loxP-mediated specific deletion of IKKbeta in sensory neurons of the dorsal root ganglion (SNS-IKKbeta(-/-)) to evaluate whether IKK plays a role in sensory neuron excitability and nociception. We observed increased sensitivity to mechanical, cold, noxious heat and chemical stimulation in SNS-IKKbeta(-/-) mice, with normal proprioceptive and motor functions as revealed by gait analysis. This was associated with increased calcium influx and increased inward currents in small- and medium-sized primary sensory neurons of SNS-IKKbeta(-/-) mice during stimulation with capsaicin or Formalin, specific activators of transient receptor potentials TRPV1 and TRPA1 calcium channels, respectively. In vitro stimulation of saphenous nerve preparations of SNS-IKKbeta(-/-) mice showed increased neuronal excitability of A- and C-fibers but unchanged A- and C-fiber conduction velocities, normal voltage-gated sodium channel currents, and normal accumulation of ankyrin G and the sodium channels Nav1.6 at NR. The results suggest that IKKbeta functions as a negative modulator of sensory neuron excitability, mediated at least in part by modulation of TRP channel sensitivity.

A key role for gp130 expressed on peripheral sensory nerves in pathological pain.

Interleukin-6 (IL-6) is a key mediator of inflammation. Inhibitors of IL-6 or of its signal transducing receptor gp130 constitute a novel class of anti-inflammatory drugs, which raise great hopes for improved treatments of painful inflammatory diseases such as rheumatoid arthritis. IL-6 and gp130 may enhance pain not only indirectly through their proinflammatory actions but also through a direct action on nociceptors (i.e., on neurons activated by painful stimuli). We found indeed that the IL-6/gp130 ligand-receptor complex induced heat hypersensitivity both in vitro and in vivo. This process was mediated by activation of PKC-delta via Gab1/2/PI(3)K and subsequent regulation of TRPV1, a member of the transient receptor potential (TRP) family of ion channels. To assess the relevance of this direct pain promoting effect of IL-6, we generated conditional knock-out mice, which lack gp130 specifically in nociceptors, and tested them in models of inflammatory and tumor-induced pain. These mice showed significantly reduced levels of inflammatory and tumor-induced pain but no changes in immune reactions or tumor growth. Our results uncover the significance of gp130 expressed in peripheral pain sensing neurons in the pathophysiology of major clinical pain disorders and suggest their use as novel pain relieving agents in inflammatory and tumor pain.

Functional properties of cutaneous A- and C-fibers 1-15 months after a nerve lesion.

The functional properties of cutaneous afferent fibers were investigated 1-15 mo after nerve lesions, which allowed regeneration into denervated skin. After crushing or transection and resuturing the rat sural nerve, ongoing activity and responses to cold, heat, and mechanical stimuli presented to the denervated skin or to the nerve distal to the lesion were examined in 273 A-fibers and 211 C-fibers. Reinnervation of skin by A-fibers was largely complete by 1-4 mo after crushing but incomplete after transection and resuturing. A few A-fibers could be activated from the nerve trunk, even after 10-15 mo. Almost all regenerated A-fibers were mechanosensitive and about 6% were cold- or heat-sensitive. A few A-fibers had ongoing activity after nerve crush. Only 15-35% of C-fibers could be activated at 1-4 mo, but 60% were excited from the skin at 10-15 mo, when many also had receptive fields within the lesioned nerve. The remaining C-fibers had receptive fields only within the nerve trunk. Responses of both intraneural and intradermal endings of C-fibers could be classified into functional groups similar to those of C-fibers in control nerves to cutaneous stimuli. The frequency of afferent C-fibers with ongoing activity that were not highly cold sensitive was 45%. We conclude that the functional characteristics of afferent A- and C-fibers are expressed by regenerating nerve endings, even when they do not reinnervate their target tissue. The reinnervation of skin by afferent C-fibers is extremely slow and may never recover to normal.

Endogenous tumor necrosis factor alpha (TNFalpha) requires TNF receptor type 2 to generate heat hyperalgesia in a mouse cancer model.

To provide a tool to investigate the mechanisms inducing and maintaining cancer-related pain and hyperalgesia, a soft tissue tumor/metastasis model was developed that is applicable in C57BL/6J wild-type and transgenic mice. We show that the experimental tumor-induced heat hyperalgesia and nociceptor sensitization were prevented by systemic treatment with the tumor necrosis factor alpha (TNFalpha) antagonist etanercept. In naive mice, exogenous TNFalpha evoked heat hyperalgesia in vivo and sensitized nociceptive nerve fibers to heat in vitro. TNFalpha enhanced the expression of the nociceptor-specific heat transducer ion channel transient receptor potential vanilloid 1 (TRPV1) and increased the amplitudes of capsaicin and heat-activated ionic currents via p38/MAP (mitogen-activated protein) kinase and PKC (protein kinase C). Deletion of the tumor necrosis factor receptor type 2 (TNFR2) gene attenuated heat hyperalgesia and prevented TRPV1 upregulation in tumor-bearing mice, whereas TNFR1 gene deletion played a minor role. We propose endogenous TNFalpha as a key player in cancer-related heat hyperalgesia and nociceptor sensitization that generates TRPV1 upregulation and sensitization via TNFR2.

Cannabinoids mediate analgesia largely via peripheral type 1 cannabinoid receptors in nociceptors.

Although endocannabinoids constitute one of the first lines of defense against pain, the anatomical locus and the precise receptor mechanisms underlying cannabinergic modulation of pain are uncertain. Clinical exploitation of the system is severely hindered by the cognitive deficits, memory impairment, motor disturbances and psychotropic effects resulting from the central actions of cannabinoids. We deleted the type 1 cannabinoid receptor (CB1) specifically in nociceptive neurons localized in the peripheral nervous system of mice, preserving its expression in the CNS, and analyzed these genetically modified mice in preclinical models of inflammatory and neuropathic pain. The nociceptor-specific loss of CB1 substantially reduced the analgesia produced by local and systemic, but not intrathecal, delivery of cannabinoids. We conclude that the contribution of CB1-type receptors expressed on the peripheral terminals of nociceptors to cannabinoid-induced analgesia is paramount, which should enable the development of peripherally acting CB1 analgesic agonists without any central side effects.

New generation 3-dimensional echocardiography for left ventricular volumetric and functional measurements: comparison with cardiac magnetic resonance.

AIMS: Non-invasive assessment of left ventricular (LV) structure and function is important in the evaluation of cardiac patients. This study was designed to test the accuracy and reproducibility of new generation 3-dimensional echocardiography (3DE) in measuring volumetric and functional LV indices as compared with current "gold standard" of non-invasive cardiac imaging, cardiac magnetic resonance (CMR). METHODS AND RESULTS: Sixty-four subjects with good acoustic windows, including 40 cardiac patients with LV ejection fraction (EF)<45%, 14 patients with EF>45% and 10 normal volunteers underwent 3DE using a commercially available Philips Sonos 7500 scanner equipped with a matrix phase-array x4 xMATRIX transducer, and CMR on a 1.5 T Signa CV/i scanner (GE Medical Systems). Volumetric assessment was performed with analytical 4D-LV-Analysis software (TomTec) for 3DE and MRI-Mass software (Medis) for CMR. We found no significant differences in LV end-diastolic volume (EDV), end-systolic volume (ESV) and EF with excellent correlations between the indices measured using 3DE and CMR (r=0.97, r=0.98, and r=0.94, respectively). Bland-Altman analysis showed bias of 7 ml for EDV, 3 ml for ESV and -1% for EF with 3DE with corresponding limits of agreement (2SD) of 28 ml, 22 ml and 10%, respectively. Intraobserver and interobserver variabilities were for EDV: 3% and 4% (3DE) vs 2% and 2% (CMR), for ESV: 3% and 6% (3DE) vs 2% and 3% (CMR), and for EF: 4% and 4% (3DE) vs 2% and 4% (CMR), respectively. CONCLUSION: New generation 3DE provides accurate and reproducible quantification of LV volumetric and functional data in subjects with good acoustic windows as compared with CMR.

Interventricular and intraventricular dyssynchrony are common in heart failure patients, regardless of QRS duration.

AIMS: The study aimed at evaluating the prevalence of interventricular and intraventricular contractile dyssynchrony in heart failure patients with either normal or prolonged QRS duration. METHODS AND RESULTS: Echocardiography and tissue Doppler imaging (TDI) were performed in 158 consecutive patients with advanced left ventricular dysfunction (LVEF<35%); 61 patients had a normal QRS duration (Group 1), 21 patients had left bundle branch block with a QRS duration between 120 and 150 ms (Group 2) and 76 patients had a QRS duration #10878;150 ms (Group 3). Interventricular dyssynchrony (defined by the presence of an interventricular mechanical delay greater than 40 ms) was found in 12.5%, 52.4% and 72% of patients in Group 1, 2 and 3, respectively (p < 0.001). Intraventricular dyssynchrony (defined by the presence of one or more differences greater than 50 ms among regional pre-ejection periods) was observed in 29.5%, 57.1% and 71% of patients in Group 1, 2 and 3, respectively (p < 0.001). No relationship was found between interventricular and intraventricular dyssynchrony. CONCLUSIONS: A substantial proportion of heart failure patients with a slightly prolonged QRS or even with normal conduction may exhibit ventricular dyssynchrony. Both standard echocardiography and TDI are necessary to describe the entire spectrum of mechanical abnormalities due to dyssynchrony.

Ectopic activity in cutaneous regenerating afferent nerve fibers following nerve lesion in the rat.

Spontaneous activity, and mechanical and thermal sensitivity were investigated in regenerating afferent nerve fibers within 4-21 days post sural nerve lesion (crush or transection and resuturing) in anaesthetized rats. About 33-40% of the myelinated (A) and 22-27% of the unmyelinated (C) fibers excited by electrical nerve stimulation exhibited at least one of these ectopic discharge properties. In total 177 A- and 169 C-fibers with ectopic activity were analysed. Most A-fibers (161/177) were mechanosensitive. Spontaneous activity (median 1 imp/s) was present in 23/177 and thermosensitivity in 14/177 A-fibers (13 of them being activated by heat stimuli). Almost all A-fibers (159/177) exhibited only one type of ectopic discharge property. Most C-fibers (94/169) were thermosensitive responding either to cold (n = 45) or to heat stimuli (n = 33) or to both (n = 16). Eighty-four of 169 C-fibers were spontaneously active (median 0.3 imp/s) and 75/169 C-fibers were mechanosensitive. Both the proportion and the discharge rate of spontaneously active C-fibers were significantly higher after crush than after section and resuturing of the nerve. About 60% of the C-fibers (101/169) had only one ectopic discharge property and 40% two or three. In conclusion, regenerating cutaneous afferent A- and C-fibers may develop mechano- and/or thermosensitivity as well as spontaneous activity. We suggest that spontaneous and evoked ectopic activity in regenerating cutaneous afferents are a function of the intrinsic functional properties of these neurons and of the interaction between the regenerating nerve fibers and non-neural cells during Wallerian degeneration in the nerve distal to the nerve lesion.

Enoximone echocardiography: a novel test to evaluate left ventricular contractile reserve in patients with heart failure on chronic beta-blocker therapy.

BACKGROUND: It has been suggested that an extensive contractile reserve identified recognised by means of dobutamine stress echocardiography may predict a better prognosis in patients with severe left ventricular dysfunction at rest. However, the clinical use of dobutamine stress echocardiography may be limited in patients with chronic heart failure by the substantial proportion of such patients treated with beta-blockers, since the inotropic response to adrenergic stimulation is known to be attenuated in patients receiving beta-adrenoceptor blockers. Enoximone is a positive inotropic agent that inhibits cyclic adenosine monophosphate-specific phosphosdiesterase. We therefore tested the hypothesis that enoximone may be an alternative to dobutamine in evaluating left ventricular contractile reserve in patients with systolic dysfunction on chronic beta-blocker therapy. METHODS: We studied 26 patients (21 males and five females) with a mean age of 58 PlusMinus; 10 years: 11 were not receiving beta-blockers (noBB group); 15 were receiving carvedilol at a mean dose of 34 mg/day (BB group). Dobutamine was infused at doses of 5 and 10 micrograms/kg/min, and enoximone at a dose of 1.5 mg/kg. RESULTS: The ejection fraction in the noBB group increased by 9% with dobutamine and 8.73% with enoximone (p = 0.86); in the BB group, it increased by 6% with dobutamine and 8.94% with enoximone (p = 0.03). Regional peak systolic velocities were evaluated by means of tissue Doppler imaging in four basal and four medium level segments. In the noBB group, they increased more with dobutamine than with enoximone in three of the eight segments; no significant differences were found in the BB group. Dobutamine induced non-sustained ventricular tachycardia in three patients and supraventricular tachycardia in one, whereas enoximone did not induce any repetitive arrhythmias. CONCLUSIONS: Enoximone might be preferable to low-dose dobutamine for evaluating left ventricular contractile reserve in chronically beta-blocked heart failure patients as it is slightly more potent and has a better safety profile.

Clinicopathological correlates can predict acute myocarditis in patients with recent-onset heart failure: preliminary data.

BACKGROUND: The aim of this study was to verify whether or not the clinical profile could be helpful in diagnosing myocarditis in patients with recent-onset (< 6 months) heart failure, suspected myocarditis and a biopsy-proven diagnosis. METHODS: From March 1998 to December 2000, 118 patients underwent a complete clinical, hemodynamic, echocardiographic and laboratory examination and a diagnostic endomyocardial biopsy in our Department; among them, 28 patients were admitted with clinically suspected myocarditis; in 9, the diagnosis was confirmed by the histopathologic findings. RESULTS: At the time of presentation, patients with biopsy-proven myocarditis showed early in-hospital admission (median 6 vs 69 days) with fever, a higher sinus rate and a significantly lower systolic blood pressure. Left ventricular dilation was observed in the non-myocarditis group only (left ventricular end-diastolic diameter 65.0 +/- 8.9 vs 52.6 +/- 5.8 mm); right ventricular function, as assessed by evaluation of the tricuspid annulus plane systolic excursion (TAPSE) and the right ventricular ejection fraction (RVEF) were found to be significantly lower in the myocarditis group (TAPSE 14.2 +/- 3.6 vs 20.3 +/- 7.0 mm; RVEF 21.3 +/- 11.1 vs 30.3 +/- 11.5%). Only patients with biopsy-proven myocarditis had an increase in serum creatine kinase and inflammatory markers (erythrocyte sedimentation rate and white blood cell count). Three cases had a clinical presentation of fulminant myocarditis showing marked increases in the serum levels of creatine kinase and inflammatory markers, and severely compromised right ventricular function and cardiac index. CONCLUSIONS: At univariate analysis, an early onset, fever, tachycardia, hypotension, a reduced right ventricular function, increased creatine kinase, erythrocyte sedimentation rate and white blood cell count were predictive of myocarditis. In patients with recent-onset heart failure, the clinical, laboratory and echocardiographic profiles can suggest, but not prove, a diagnosis of myocarditis.