Endothelial dysfunction and altered endothelial biomarkers in patients with post-COVID-19 syndrome and chronic fatigue syndrome (ME/CFS).

BACKGROUND: Fatigue, exertion intolerance and post-exertional malaise are among the most frequent symptoms of Post-COVID Syndrome (PCS), with a subset of patients fulfilling criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). As SARS-CoV-2 infects endothelial cells, causing endotheliitis and damaging the endothelium, we investigated endothelial dysfunction (ED) and endothelial biomarkers in patients with PCS. METHODS: We studied the endothelial function in 30 PCS patients with persistent fatigue and exertion intolerance as well as in 15 age- and sex matched seronegative healthy controls (HCs). 14 patients fulfilled the diagnostic criteria for ME/CFS. The other patients were considered to have PCS. Peripheral endothelial function was assessed by the reactive hyperaemia index (RHI) using peripheral arterial tonometry (PAT) in patients and HCs. In a larger cohort of patients and HCs, including post-COVID reconvalescents (PCHCs), Endothelin-1 (ET-1), Angiopoietin-2 (Ang-2), Endocan (ESM-1), IL-8, Angiotensin-Converting Enzyme (ACE) and ACE2 were analysed as endothelial biomarkers. RESULTS: Five of the 14 post-COVID ME/CFS patients and five of the 16 PCS patients showed ED defined by a diminished RHI (< 1.67), but none of HCs exhibited this finding. A paradoxical positive correlation of RHI with age, blood pressure and BMI was found in PCS but not ME/CFS patients. The ET-1 concentration was significantly elevated in both ME/CFS and PCS patients compared to HCs and PCHCs. The serum Ang-2 concentration was lower in both PCS patients and PCHCs compared to HCs. CONCLUSION: A subset of PCS patients display evidence for ED shown by a diminished RHI and altered endothelial biomarkers. Different associations of the RHI with clinical parameters as well as varying biomarker profiles may suggest distinct pathomechanisms among patient subgroups.

Iron deficiency is related to low functional outcome in patients at early rehabilitation after acute stroke.

BACKGROUND: Iron deficiency (ID) is a common co-morbidity in patients with cardiovascular disease and contributes to impaired functional capacity. The relevance of ID in patients in recovery after acute stroke is not known. We assessed the prevalence of ID and anaemia in relation to functional capacity and to recovery during early rehabilitation after stroke. METHODS: This observational study enrolled consecutively 746 patients with ischaemic or haemorrhagic stroke at in-patient early rehabilitation (age 68 ± 13 years, female 47%, ischaemic stroke 87%). Functional capacity was assessed before and after rehabilitation using Barthel index (reha-BI), motricity index (MI), trunk control test (TCT), and functional ambulatory category (FAC). ID was defined as ferritin <100 µg/L or as transferrin saturation (TSAT) < 20% if ferritin was 100- < 300 µg/L or if CrP > 5 mg/L. Anaemia was defined as Hb < 12 g/dL (women) and <13 g/dL (men). RESULTS: The prevalence of ID and anaemia before rehabilitation were 45% and 46%, respectively, and remained high at discharge (after 27 ± 17 days) at 40% and 48%, respectively. Patients with ID had lower functional capacity compared with patients without ID (reha-BI 20 [±86] vs. 40 [±80], MI 64 [±66] vs. 77 [±41], TCT 61 [±76] vs. 100 [±39], FAC 1 [±4] vs. 4 [±4]; median [IQR], all P < 0.001). ID was related to inflammation (OR 2.68 [95% CI 1.98-3.63], P < 0.001), female sex (OR 2.13 [95% CI 1.59-2.85], P < 0.001), haemorrhagic stroke (OR 1.70 [95% CI 1.11-2.61], P = 0.015), initial treatment on stroke unit (OR 3.59 [95% CI 1.08-11.89], P < 0.001), and anaemia (OR 2.94 [95% CI 2.18-3.96], P < 0.001), while age, BMI, and renal function were not related to ID. In adjusted analysis, ID was associated with low functional capacity in all functional scores: reha-BI (OR 1.66 [95% CI 1.08-2.54], P = 0.02), motricity index (OR 1.94 [95% CI 1.36-2.76], P < 0.001), trunk control test (OR 2.34 [95% CI] 1.64-3.32, P < 0.001) and functional ambulatory category (OR 1.77 [95% CI 1.2-2.63], P < 0.02). Functional capacity improved during rehabilitation regardless of presence of ID, but functional outcome remained significantly lower in patients with ID at the end of rehabilitation (rehab BI and MI, both P < 0.001). CONCLUSIONS: Iron deficiency and anaemia are common and persistent findings in patients after acute stroke. ID and anaemia are independently related to lower functional capacity after acute stroke and to poor functional outcome after rehabilitation. Regular assessment of iron status may identify patients at risk of low functional recovery.

Iron Deficiency and Reduced Muscle Strength in Patients with Acute and Chronic Ischemic Stroke.

(1) Introduction: Iron deficiency (ID) contributes to impaired functional performance and reduced quality of life in patients with chronic illnesses. The role of ID in stroke is unclear. The aim of this prospective study was to evaluate the prevalence of ID and to evaluate its association with long-term functional outcome in patients with ischemic stroke. (2) Patients and Methods: 140 patients (age 69 ± 13 years, BMI 27.7 ± 4.6 kg/m², mean ± SD) admitted to a university hospital stroke Unit, with acute ischemic stroke of the middle cerebral artery were consecutively recruited to this observational study. Study examinations were completed after admission (3 ± 2 days after acute stroke) and at one-year follow up (N = 64, 382 ± 27 days after stroke). Neurological status was evaluated according to the National Institute of Health Stroke Scale (NIHSS) and the modified Rankin scale (mRS). Muscle isometric strength of the non-affected limb was assessed by the maximum handgrip test and knee extension leg test. ID was diagnosed with serum ferritin levels ≤ 100 µg/L (ID Type I) or 100-300 µg/L if transferrin saturation (TSAT) < 20% (ID Type II). (3) Results: The prevalence of ID in acute stroke patients was 48% (N = 67), with about two-thirds of patients (N = 45) displaying ID Type I and one-third (N = 22) Type II. Handgrip strength (HGS) and quadriceps muscle strength were reduced in patients with ID compared to patients without ID at baseline (HGS: 26.5 ± 10.4 vs. 33.8 ± 13.2 kg, p < 0.001 and quadriceps: 332 ± 130 vs. 391 ± 143 N, p = 0.06). One year after stroke, prevalence of ID increased to 77% (p = 0.001). While an improvement of HGS was observed in patients with normal iron status, patients with ID had no improvement in HGS difference (4.6 ± 8.3 vs. -0.7 ± 6.5 kg, p < 0.05). Patients with ID remained with lower HGS compared to patients with normal iron status (28.2 ± 12.5 vs. 44.0 ± 8.6 kg, p < 0.0001). (4) Conclusions: Prevalence of ID was high in patients after acute stroke and further increased one year after stroke. ID was associated with lower muscle strength in acute stroke patients. In patients with ID, skeletal muscle strength did not improve one year after stroke.

Tolerability and Efficacy of s.c. IgG Self-Treatment in ME/CFS Patients with IgG/IgG Subclass Deficiency: A Proof-of-Concept Study.

BACKGROUND: Chronic fatigue syndrome (ME/CFS) is a complex disease frequently triggered by infections. IgG substitution may have therapeutic effect both by ameliorating susceptibility to infections and due to immunomodulatory effects. METHODS: We conducted a proof of concept open trial with s.c. IgG in 17 ME/CFS patients suffering from recurrent infections and mild IgG or IgG subclass deficiency to assess tolerability and efficacy. Patients received s.c. IgG therapy of 0.8 g/kg/month for 12 months with an initial 2 months dose escalation phase of 0.2 g and 0.4 g/kg/month. RESULTS: Primary outcome was improvement of fatigue assessed by Chalder Fatigue Scale (CFQ; decrease ≥ 6 points) and of physical functioning assessed by SF-36 (increase ≥ 25 points) at month 12. Of 12 patients receiving treatment per protocol 5 had a clinical response at month 12. Two additional patients had an improvement according to this definition at months 6 and 9. In four patients treatment was ceased due to adverse events and in one patient due to disease worsening. We identified LDH and soluble IL-2 receptor as potential biomarker for response. CONCLUSION: Our data indicate that self-administered s.c. IgG treatment is feasible and led to clinical improvement in a subset of ME/CFS patients.

Ischemic Stroke and Heart Failure: Facts and Numbers. An Update.

Heart failure (HF) is a severe clinical syndrome accompanied by a number of comorbidities. Ischemic stroke occurs frequently in patients with HF as a complication of the disease. In the present review, we aimed to summarize the current state of research on the role of cardio-cerebral interactions in the prevalence, etiology, and prognosis of both diseases. The main pathophysiological mechanisms underlying the development of stroke in HF and vice versa are discussed. In addition, we reviewed the results of recent clinical trials investigating the prevalence and prevention of stroke in patients with HF.

Hand grip strength and fatigability: correlation with clinical parameters and diagnostic suitability in ME/CFS.

BACKGROUND: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex and debilitating disease accompanied by muscular fatigue and pain. A functional measure to assess muscle fatigability of ME/CFS patients is, however, not established in clinical routine. The aim of this study is to evaluate by assessing repeat maximum handgrip strength (HGS), muscle fatigability as a diagnostic tool and its correlation with clinical parameters. METHODS: We assessed the HGS of 105 patients with ME/CFS, 18 patients with Cancer related fatigue (CRF) and 66 healthy controls (HC) using an electric dynamometer assessing maximal (Fmax) and mean force (Fmean) of ten repetitive measurements. Results were correlated with clinical parameters, creatinine kinase (CK) and lactate dehydrogenase (LDH). Further, maximum isometric quadriceps strength measurement was conducted in eight ME/CFS patients and eight HC. RESULTS: ME/CFS patients have a significantly lower Fmax and Fmean HGS compared to HC (p < 0.0001). Further, Fatigue Ratio assessing decline in strength during repeat maximal HGS measurement (Fmax/Fmean) was higher (p ≤ 0.0012). The Recovery Ratio after an identical second testing 60 min later was significantly lower in ME/CFS compared to HC (Fmean2/Fmean1; p ≤ 0.0020). Lower HGS parameters correlated with severity of disease, post-exertional malaise and muscle pain and with higher CK and LDH levels after exertion. CONCLUSION: Repeat HGS assessment is a sensitive diagnostic test to assess muscular fatigue and fatigability and an objective measure to assess disease severity in ME/CFS.

Early rehabilitation after stroke: relationship between the heart rate variability and functional outcome.

AIMS: Impaired autonomic nervous system regulation is frequently observed in patients with stroke. The aim of this prospective study was to evaluate the impact of cardiac autonomic tone on functional outcome after the early post-stroke rehabilitation. METHODS AND RESULTS: One hundred and three consecutive patients (67 ± 11 years, body mass index (BMI) 27.1 ± 5.4 kg/m2 , 64% men) with ischaemic (84% of patients) and haemorrhagic stroke were studied. Depressed heart rate variability (HRV), as a surrogate marker of increased sympathetic tone, was defined by the standard deviation of NN intervals < 100 ms and HRV triangular index ≤ 20 assessed from a 24 h Holter electrocardiogram at admission to rehabilitation (23 ± 16 days after stroke). Twenty-two per cent of patients had depressed HRV at baseline and were comparable with patients with normal HRV with regard to their functional [Barthel Index (BI), modified Rankin Scale (mRS), and Rivermead Motor Assessment (RMA)] and biochemical status. After a 4-week follow-up, 70% of patients with depressed HRV showed a cumulative functional disability, defined by mRS ≥ 4, BI ≤ 70, and RMA ≤ 5, in contrast to patients with normal HRV (35%, P = 0.003). Patients with depressed HRV showed a worse functional status by BI (-16%, P < 0.001), RMA (-12%, P < 0.05), and mRS (+16%, P < 0.01), compared with patients with normal HRV. Cumulative functional disability was associated with depressed HRV (odds ratio 4.25, 95% confidence interval 1.56-11.54, P < 0.005) after adjustment for age, sex, and body mass index (odds ratio 4.6, 95% confidence interval 1.42-14.97, P < 0.05). CONCLUSIONS: The presence of autonomic cardiovascular dysregulation in patients with subacute stroke was associated with adverse functional outcome after the early post-stroke rehabilitation.

Acute effects of oral triglyceride load on dynamic changes in peripheral endothelial function in heart failure patients with reduced ejection fraction and healthy controls.

BACHGROUND: Postprandial hyperlipaemia impairs endothelial function, possibly via oxidative-stress-mediated mechanisms. The aim of this study was to evaluate the acute effects of an oral triglyceride load (OTGL) on peripheral endothelial function in heart failure patients with reduced ejection fraction (HFrEF) compared to healthy controls. DESIGN: Prospective cross-sectional. METHODS: We enrolled 47 patients with HFrEF and 20 healthy controls. Peripheral endothelial function was assessed with EndoPAT2000 technology using a reactive hyperaemia index (RHI) and pulse wave amplitude (PWA) at baseline (after 8-h overnight fasting) as well as 1, 2, 3 and 4-h post-OTGL consumption (250-ml cream drink). Pulse wave amplitude index (PWAI) was calculated as a ratio of PWA at each time point to the baseline PWA. RESULTS: RHI at baseline was lower in HFrEF patients compared to controls (1.7 ± 0.3 and 2.3 ± 0.6, respectively; P = 0.001). The OTGL accounted for a physiologic increase in PWA in healthy controls (p = 0.01), but this change was not observed in HFrEF patients. After 4 h, vasodilator response was significantly increased in healthy controls but not patients with HFrEF (2.3 ± 1.3 vs. 1.3 ± 0.8 respectively, P < 0.05). CONCLUSIONS: The main finding of this study was the impaired postprandial dynamic changes in peripheral endothelial function in patients with HFrEF compared to healthy controls. A high-fat load that caused acute hypertriglyceridaemia significantly increased resting blood flow and peak flow at reactive hyperaemia in healthy subjects. By contrast, patients with HFrEF exhibited impaired dynamic changes in peripheral endothelial function after oral triglyceride load.

Peripheral endothelial dysfunction in myalgic encephalomyelitis/chronic fatigue syndrome.

AIMS: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex multisystem disease. Evidence for disturbed vascular regulation comes from various studies showing cerebral hypoperfusion and orthostatic intolerance. The peripheral endothelial dysfunction (ED) has not been sufficiently investigated in patients with ME/CFS. The aim of the present study was to examine peripheral endothelial function in patients with ME/CFS. METHODS AND RESULTS: Thirty-five patients [median age 40 (range 18-70) years, mean body mass index 23.8 ± 4.2 kg/m2 , 31% male] with ME/CFS were studied for peripheral endothelial function assessed by peripheral arterial tonometry (EndoPAT2000). Clinical diagnosis of ME/CFS was based on Canadian Criteria. Nine of these patients with elevated antibodies against ß2-adrenergic receptor underwent immunoadsorption, and endothelial function was measured at baseline and 3, 6, and 12 months follow-up. ED was defined by reactive hyperaemia index ≤1.81. Twenty healthy subjects of similar age and body mass index were used as a control group. Peripheral ED was found in 18 of 35 patients (51%) with ME/CFS and in 4 healthy subjects (20%, P < 0.05). Patients with ED, in contrast to patients with normal endothelial function, reported more severe disease according to Bell score (31 ± 12 vs. 40 ± 16, P = 0.04), as well as more severe fatigue-related symptoms (8.62 ± 0.87 vs. 7.75 ± 1.40, P = 0.04) including a higher demand for breaks [9.0 (interquartile range 7.0-10.0) vs. 7.5 (interquartile range 6.0-9.25), P = 0.04]. Peripheral ED showed correlations with more severe immune-associated symptoms (r = -0.41, P = 0.026), such as sore throat (r = -0.38, P = 0.038) and painful lymph nodes (r = -0.37, P = 0.042), as well as more severe disease according to Bell score (r = 0.41, P = 0.008) and symptom score (r = -0.59, P = 0.005). There were no differences between the patient group with ED and the patient group with normal endothelial function regarding demographic, metabolic, and laboratory parameters. Further, there was no difference in soluble vascular cell adhesion molecule and soluble intercellular adhesion molecule levels. At baseline, peripheral ED was observed in six patients who underwent immunoadsorption. After 12 months, endothelial function had improved in five of these six patients (reactive hyperaemia index 1.58 ± 0.15 vs. 2.02 ± 0.46, P = 0.06). CONCLUSIONS: Peripheral ED is frequent in patients with ME/CFS and associated with disease severity and severity of immune symptoms. As ED is a risk factor for cardiovascular disease, it is important to elucidate if peripheral ED is associated with increased cardiovascular morbidity and mortality in ME/CFS.

Body weight changes and incidence of cachexia after stroke.

BACKGROUND: Body weight loss is a frequent complication after stroke, and its adverse effect on clinical outcome has been shown in several clinical trials. The purpose of this prospective longitudinal single-centre observational study was to investigate dynamical changes of body composition and body weight after ischemic stroke and an association with functional outcome. METHODS: Sixty-seven consecutive patients (age 69 ± 11 years, body mass index 27.0 ± 4.1 kg/m2 , 42% female patient, mean ± SD) with acute ischemic stroke with mild to moderate neurological deficit (National Institute of Health Stroke Scale median 4, ranged 0-12) were analysed in the acute phase (4 ± 2 days) and at 12 months (389 ± 26 days) follow-up. Body composition was examined by dual energy X-ray absorptiometry. Cachexia was defined according to the consensus definition by body weight loss ≥5% within 1 year and additional clinical signs. Lean tissue wasting was considered if a ratio of upper and lower limbs lean mass sum to squared height (kg/m2 ) was ≤5.45 kg/m2 for female patient and ≤7.25 kg/m2 for male patient. RESULTS: According to the body weight changes after 12 months, 42 (63%) patients had weight gain or stable weight, 11 (16%) patients had moderate weight loss, and 14 (21%) patients became cachectic. A relative decline of 19% of fat tissue and 6.5% of lean tissue was observed in cachectic patients, while no changes of lean tissue were observed in non-cachectic patients after 12 months. The modified Rankin Scale was 48% higher (2.1 ± 1.6, P < 0.05), Barthel Index was 22% lower (71 ± 39, P < 0.01), and handgrip strength was 34% lower (21.9 ± 13.0, P < 0.05) in cachectic compared to non-cachectic patients after 12 months. The low physical performance if defined by Barthel Index <60 points was linked to the lean tissue wasting (OR 44.8, P < 0.01), presence of cachexia (OR 20.8, P < 0.01), and low body mass index <25 kg/m2 (OR 11.5, P < 0.05). After adjustment for cofounders, lean tissue wasting remained independently associated with the low physical performance at 12 months follow-up (OR 137.9, P < 0.05). CONCLUSIONS: In this cohort study, every fifth patient with ischemic stroke fulfilled the criteria of cachexia within 12 months after index event. The incidence of cachexia was 21%. Cachectic patients showed the lowest functional and physical capacity.

Heart-brain Interactions in Heart Failure.

Heart failure (HF) is a complex disease with a growing incidence worldwide. HF is accompanied by a wide range of conditions which affect disease progression, functional performance and contribute to growing healthcare costs. The interactions between a failing myocardium and altered cerebral functions contribute to the symptoms experienced by patients with HF, affecting many comorbidities and causing a poor prognosis. This article provides a condensed version of the 2018 position paper from the Study Group on Heart and Brain Interaction of the Heart Failure Association. It addresses the reciprocal impact on HF of several pathological brain conditions, including acute and chronic low perfusion of the brain, and impairment of higher cortical and brain stem functions. Treatment-related interactions - medical, interventional and device-related - are also discussed.

Immunoadsorption to remove ß2 adrenergic receptor antibodies in Chronic Fatigue Syndrome CFS/ME.

INTRODUCTION: Infection-triggered disease onset, chronic immune activation and autonomic dysregulation in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) point to an autoimmune disease directed against neurotransmitter receptors. We had observed elevated autoantibodies against ß2 adrenergic receptors, and muscarinic 3 and 4 acetylcholine receptors in a subset of patients. Immunoadsorption (IA) was shown to be effective in removing autoantibodies and improve outcome in various autoimmune diseases. METHODS: 10 patients with post-infectious CFS/ME and elevated ß2 autoantibodies were treated with IA with an IgG-binding column for 5 days. We assessed severity of symptoms as outcome parameter by disease specific scores. Antibodies were determined by ELISA and B cell phenotype by flow cytometry. RESULTS: IgG levels dropped to median 0.73 g/l (normal 7-16 g/l) after the 4th cycle of IA, while IgA and IgM levels remained unchanged. Similarly, elevated ß2 IgG antibodies rapidly decreased during IA in 9 of 10 patients. Also 6 months later ß2 autoantibodies were significantly lower compared to pretreatment. Frequency of memory B cells significantly decreased and frequency of plasma cells increased after the 4th IA cycle. A rapid improvement of symptoms was reported by 7 patients during the IA. 3 of these patients had long lasting moderate to marked improvement for 6-12+ months, 2 patients had short improvement only and 2 patients improved for several months following initial worsening. CONCLUSIONS: IA can remove autoantibodies against ß2 adrenergic receptor and lead to clinical improvement. B cell phenotyping provides evidence for an effect of IA on memory B cell development. Data from our pilot trial warrants further studies in CFS/ME.

Cardiac muscle wasting in individuals with cancer cachexia.

AIMS: Cachexia is a severe complication of cancer that adversely affects the course of the disease and is associated with high rates of mortality. Patients with cancer manifest symptoms, such as fatigue, shortness of breath, and impaired exercise tolerance, which are clinical signs of chronic heart failure. The aim of this study was to evaluate cardiac muscle wasting in cancer individuals. METHODS AND RESULTS: We retrospectively analysed 177 individuals who died of cancer, including 58 lung, 60 pancreatic, and 59 gastrointestinal (GI) cancers, and 42 cancer-free controls who died of other, non-cardiovascular reasons. Cancer cachexia (CC) was defined based on clinical and/or pathological diagnosis, body mass index (BMI) <20.0 kg/m2 and/or oedema-free body weight loss of 5.0% during the previous year or less. The pathology reports were analysed for BMI, heart weight (HW), and left and right ventricular wall thicknesses (LVWT and RVWT, respectively). The analysis of clinical data included recording of biochemical parameters and medication data of study patients. CC was detected in 54 (30.5%) subjects. Individuals with CC had a significantly lower HW than non-cachectic subjects (363.1 ± 86.2 vs. 447.0 ± 128.9 g, P < 0.001) and control group (412.9 ± 75.8 g, P < 0.05). BMI correlated with HW in cases with GI cancer (r = 0.44, P < 0.001), lung cancer (r = 0.53, P < 0.0001), and pancreatic cancer (r = 0.39, P < 0.01). CONCLUSIONS: Body weight loss in individuals with lung, pancreatic, and GI cancers is accompanied by a decrease in HW. In patients with CC who receive cancer treatment, screening for cardiac muscle wasting may have clinical importance.

Sleep-Disordered Breathing in Acute Ischemic Stroke: A Mechanistic Link to Peripheral Endothelial Dysfunction.

BACKGROUND: Sleep-disordered breathing (SDB) after acute ischemic stroke is frequent and may be linked to stroke-induced autonomic imbalance. In the present study, the interaction between SDB and peripheral endothelial dysfunction (ED) was investigated in patients with acute ischemic stroke and at 1-year follow-up. METHODS AND RESULTS: SDB was assessed by transthoracic impedance records in 101 patients with acute ischemic stroke (mean age, 69 years; 61% men; median National Institutes of Health Stroke Scale, 4) while being on the stroke unit. SDB was defined by apnea-hypopnea index ≥5 episodes per hour. Peripheral endothelial function was assessed using peripheral arterial tonometry (EndoPAT-2000). ED was defined by reactive hyperemia index ≤1.8. Forty-one stroke patients underwent 1-year follow-up (390±24 days) after stroke. SDB was observed in 57% patients with acute ischemic stroke. Compared with patients without SDB, ED was more prevalent in patients with SDB (32% versus 64%; P<0.01). After adjustment for multiple confounders, presence of SDB remained independently associated with ED (odds ratio, 3.1; [95% confidence interval, 1.2-7.9]; P<0.05). After 1 year, the prevalence of SDB decreased from 59% to 15% (P<0.001). Interestingly, peripheral endothelial function improved in stroke patients with normalized SDB, compared with patients with persisting SDB (P<0.05). CONCLUSIONS: SDB was present in more than half of all patients with acute ischemic stroke and was independently associated with peripheral ED. Normalized ED in patients with normalized breathing pattern 1 year after stroke suggests a mechanistic link between SDB and ED. CLINICAL TRIAL REGISTRATION: URL: https://drks-neu.uniklinik-freiburg.de. Unique identifier: DRKS00000514.

Longer-term impact of hemiparetic stroke on skeletal muscle metabolism-A pilot study.

BACKGROUND: Hemiparetic stroke leads to structural and metabolic alterations of skeletal muscle tissue, thereby contributing to functional impairment associated with stroke. In situ metabolic processes at tissue level in skeletal muscle have not been investigated. We hypothesize that muscular metabolic capacity is limited after hemiparetic stroke, and that changes affect rather the paretic than non-paretic limb. METHODS: Nine male hemiparetic stroke survivors (age, 62±8years; BMI, 28±4kg/m2; median stroke latency, 23months ranging from 7 to 34months poststroke) underwent dynamic in situ measurements of carbohydrate and lipid metabolism at fasting condition and during oral glucose tolerance testing, using bilateral microdialysis. Results were compared to 8 healthy male subjects of similar age and BMI. RESULTS: Tissue perfusion, fasting and postprandial profiles of interstitial metabolites glucose, pyruvate, lactate and glycerol did not differ between paretic and non-paretic muscle. Patients displayed higher fasting and postprandial dialysate glycerol levels compared to controls (P<0.001) with elevated plasma FFA (fasting FFA; 0.63±0.23 vs. 0.29±0.17mmol/L; P=0.004). Glycolytic activity was higher in patients vs. controls, with increased lactate production upon glucose load (P<0.001). CONCLUSIONS: An elevated lipolytic and glycolytic activity on tissue level suggests an impaired substrate metabolism with blunted oxidative metabolism in bilateral skeletal muscle in patients after hemiparetic stroke. Muscular metabolic properties did not differ between paretic and non-paretic leg. Further work is needed to investigate the clinical impact of this impaired muscular metabolic capacity in post-stroke patients.