Treatment of patients with multiple organ dysfunction syndrome (MODS) with an electromagnetic field coupled to biorhythmically defined impulse configuration: the MicrocircMODS study.

BACKGROUND: To potentially improve impaired vasomotion of patients with multiple organ dysfunction syndrome (MODS), we tested whether an electromagnetic field of low flux density coupled with a biorhythmically defined impulse configuration (Physical Vascular Therapy BEMER®, PVT), in addition to standard care, is safe and feasible and might improve disturbed microcirculatory blood flow and thereby improve global haemodynamics. METHODS: In a prospective, monocentric, one-arm pilot study, 10 MODS patients (APACHE II score 20-35) were included. Patients were treated, in addition to standard care, for 4 days with PVT (3 treatment periods of 8 min each day; day 1: field intensity 10.5 µT; day 2:14 µT, day 3:17.5 µT; day 4:21.0 µT). Primary endpoint was the effect of PVT on sublingual microcirculatory perfusion, documented by microvascular flow index (MFI). Patient safety, adverse events, and outcomes were documented. RESULTS: An increase in MFI by approximately 25% paralleled 4-day PVT, with the increase starting immediately after the first PVT and lasting over the total 4-day treatment period. Concerning global haemodynamics (secondary endpoints), halving vasopressor use within 24 h, and haemodynamic stabilisation paralleled 4-day PVT with an increase in cardiac index, stroke volume index, and cardiac power index by 30%-50%. No adverse events (AEs) or serious adverse events (SAEs) were classified as causally related to the medical product (PVT) or study. Three patients died within 28 days and one patient between 28 and 180 days. CONCLUSION: PVT treatment was feasible and safe and could be performed without obstruction of standard patient care. An increase in microcirculatory blood flow, a rapid reduction in vasopressor use, and an improvement in global haemodynamics paralleled PVT treatment. Findings of this pilot study allowed forming a concept for a randomized trial for further proof.

Intravital microscopy - A novel tool in characterizing congestive heart failure in experimental autoimmune myocarditis.

AIMS: Experimental autoimmune myocarditis (EAM) is a widely used murine model, in which cellular myocardial infiltration resembles human viral myocarditis. Although myocarditis can be readily assessed on histology, heart failure has not been fully characterized, as there are limitations in available markers and difficulties in hemodynamic measurements, especially on small rodents. We investigated whether intravital microscopy of the microcirculation can be used to characterize heart failure in EAM. METHODS: BALB/c mice (n = 10 versus n = 5 controls) were immunized with alpha myosin heavy chain peptide and myocarditis was confirmed on hematoxylin-eosin (HE) histology on day 21. Echocardiography assessment included ejection fraction (EF), fractional shortening (FS), mitral valve doppler, left-ventricular end-diastolic diameter (LVEDd) and diastolic intra-ventricular septum thickness (IVSd). Microcirculatory analysis was performed using a sidestream dark field (SDF) microcirculation camera. The proportion of perfused vessels (PPV) and perfused vessel density (PVD) were recorded on the intestinal mucosa of the anaesthesized mice. RESULTS: Immunized mice developed EAM with typical cellular infiltration (p < 0.003), left-ventricular hypertrophy (IVSd, p = 0.027) and diastolic dysfunction (E/A, p = 0.028) without significant EF reduction (p = 0.845) or LV dilation (p = 0.854). SDF recording consisted mainly of venules, as capillaries were too small. PPV and PVD were significantly increased in EAM mice (p 0.001 and 0.01 respectively) and correlated significantly with the histological myocarditis severity score (r = 0.557, p = 0.03 and r = 0.57, p = 0.025 respectively), whereas PPV but not PVD correlated with IVSd (r = 0.588, p = 0.02) and E/A ratio (r = 0.703, p = 0.003). CONCLUSIONS: Intravital microscopy can be used to characterize post-capillary intestinal perfusion of EAM mice. Thus we show a congestion of intestinal venules in EAM which correlates to the severity of myocarditis.

Increased arginase levels contribute to impaired perfusion after cardiopulmonary resuscitation.

OBJECTIVES: The postcardiac arrest syndrome occurs after global hypoxia leading to microcirculatory impairment. Nitric oxide (NO) is a key molecule regulating microvascular function. The enzyme arginase has been suggested to modulate microvascular function by regulating NO metabolism. Therefore, we investigated whether arginase increases following global hypoxia and resuscitation and tested whether arginase inhibition influences altered microcirculation in resuscitated patients. METHODS: To determine the effect of global hypoxia on circulating arginase levels, fourteen healthy subjects were exposed to hypoxia in a normobaric hypoxia chamber (FiO² = 9·9%). In addition, 31 resuscitated patients were characterized clinically, and arginase 1 was measured on days 1 and 3. In eight resuscitated patients, a microcirculatory analysis was performed using a sidestream darkfield microcirculation camera. Perfused capillary density (PCD) was recorded before and after sublingual incubation of N-omega-hydroxy-nor-l-arginine (nor-NOHA) alone or together with the NOS inhibitor NG-monomethyl-l-arginine (l-NMMA). RESULTS: Circulating arginase 1 levels increased in healthy volunteers following global hypoxia in the hypoxic chamber (P < 0·01). In addition, arginase 1 levels were higher on day 1 (69·1 ± 83·3 ng/mL) and on day 3 (44·2 ± 65·6 ng/mL) after resuscitation than in control subjects (P < 0·001). Incubation of the sublingual mucosa with nor-NOHA increased microcirculatory perfusion (P < 0·001). This effect was inhibited by co-incubation with K-NMMA. CONCLUSIONS: Circulating arginase 1 levels are increased following exposure to global hypoxia and in patients who have been successfully resuscitated after cardiac arrest. Topical arginase inhibition improves microcirculatory perfusion following resuscitation. This is of potential therapeutic importance for the postcardiac arrest syndrome.

Increased arginase levels in heart failure represent a therapeutic target to rescue microvascular perfusion.

OBJECTIVES: Heart failure (HF) is defined as the incapability of the heart to serve the tissues adequately with blood. This includes changes in microvascular perfusion. A mechanism aggravating perfusion disturbances in HF is endothelial dysfunction by reduced bioavailability of nitric oxide (NO). A mechanism possibly contributing to low NO bioavailability is the upregulation of arginase. Therefore, we investigated circulating arginase levels in patients with HF and its consequences for microvascular perfusion. METHODS: A first group consisted of eighty patients with chronic HF. Patients were characterized by echocardiography and laboratory values. Arginase 1 levels were determined using a commercially available ELISA. A second experimental group included eight patients with severe heart failure. Using sidestream darkfield intravital microscopy sublingual microcirculation was quantified before and after the topical incubation of nor-NOHA as arginase inhibitor and L-NMMA as NO synthase inhibitor. RESULTS: Circulating arginase-1 levels were significantly higher in patients with heart failure compared to controls (p < 0.001). Patients with severe heart failure (NYHA III/IV) had significantly higher arginase-1 levels compared to patients with mild heart failure (p < 0.01, NYHA I/II). Sublingual perfused capillary density increased significantly (p < 0.01) following incubation with nor-NOHA. However, this effect was abolished when nor-NOHA was co-incubated with L-NMMA. CONCLUSIONS: In conclusion, circulating arginase 1 levels are elevated in patients with HF. A topical inhibition of arginase in these patients leads to improved microcirculation by a NO dependent mechanism. Inhibition of arginase is a possible therapeutic target to rescue microcirculation in patients with HF.