CD73-Adenosinergic Axis Mediates the Protective Effect of Extracellular Vesicles Derived from Mesenchymal Stromal Cells on Ischemic Renal Damage in a Rat Model of Donation after Circulatory Death.

We propose a new organ-conditioning strategy based on mesenchymal stromal cell (MSCs)/extracellular vesicle (EVs) delivery during hypothermic perfusion. MSCs/EVs marker CD73 is present on renal proximal tubular cells, and it protects against renal ischemia-reperfusion injury by converting adenosine monophosphate into adenosine (ADO). In this study, after checking if CD73-silenced EVs (EVsi) would impact in vitro tubular-cell proliferation, we perfused kidneys of a rat model of donation after circulatory death, with Belzer solution (BS) alone, BS supplemented with MSCs, EVs, or EVsi. The ADO and ATP levels were measured in the effluents and tissues. Global renal ischemic damage score (GRS), and tubular cell proliferation index (IPT) were evaluated in the tissue. EVsi did not induce cell proliferation in vitro. Ex vivo kidneys perfused with BS or BS + EVsi showed the worst GRS and higher effluent ADO levels than the MSC- and EV-perfused kidneys. In the EV-perfused kidneys, the tissue and effluent ATP levels and IPT were the highest, but not if CD73 was silenced. Tissue ATP content was positively correlated with tissue ADO content and negatively correlated with effluent ADO level in all groups. In conclusion, kidney conditioning with EVs protects against ischemic damage by activating the CD73/ADO system.

Despite Inflammation, Supplemented Essential Amino Acids May Improve Circulating Levels of Albumin and Haemoglobin in Patients after Hip Fractures.

Essential amino acids (EAAs) are nutritional substrates that promote body protein synthesis; thus we hypothesised that their supplementation may improve circulating albumin (Alb) and haemoglobin (Hb) in rehabilitative elderly patients following hip fractures (HF). Out of the 145 HF patients originally enrolled in our study, 112 completed the protocol. These subjects were divided into two randomised groups, each containing 56 patients. For a period of two months, one group (age 81.4 ± 8.1 years; male/female 27/29) received a placebo, and the other (age 83.1 ± 7.5 years; male/female 25/31) received 4 + 4 g/day oral EAAs. At admission, the prevalence of both hypoAlb (<3.5 g/dL) and hypoHb (<13 g/dL male, <12 g/dL female) was similar in the placebo group (64.3% hypoAlb, 66% hypoHb) and the treated group of patients (73.2% hypoAlb, 67.8% hypoHb). At discharge, however, the prevalence of hypoAlb had reduced more in EAAs than in placebo subjects (31.7% in EAAs vs. 77.8% in placebo; p < 0.001). There was a 34.2% reduction of anaemia in hypoHb in EAA subjects and 18.9% in placebo subjects, but the difference was not statistically significant. Oral supplementation of EAAs improves hypoAlb and, to a lesser extent, Hb in elderly rehabilitative subjects with hip fractures. Anaemia was reduced in more than one third of patients, which, despite not being statistically significant, may be clinically relevant.

The Hip Functional Retrieval after Elective Surgery May Be Enhanced by Supplemented Essential Amino Acids.

It is not known whether postsurgery systemic inflammation and plasma amino acid abnormalities are still present during rehabilitation of individuals after elective hip arthroplasty (EHA). Sixty subjects (36 females; age 66.58 ± 8.37 years) were randomized to receive 14-day oral EAAs (8 g/day) or a placebo (maltodextrin). At admission to and discharge from the rehabilitation center, serum C-reactive protein (CRP) and venous plasma amino acid concentrations were determined. Post-EHA hip function was evaluated by Harris hip score (HHS) test. Ten matched healthy subjects served as controls. At baseline, all patients had high CRP levels, considerable reduction in several amino acids, and severely reduced hip function (HHS 40.78 ± 2.70 scores). After treatment, inflammation decreased both in the EAA group and in the placebo group. Only EAA patients significantly improved their levels of glycine, alanine, tyrosine, and total amino acids. In addition, they enhanced the rate of hip function recovery (HHS) (from baseline 41.8 ± 1.15 to 76.37 ± 6.6 versus baseline 39.78 ± 4.89 to 70.0 ± 7.1 in placebo one; p = 0.006). The study documents the persistence of inflammation and plasma amino acid abnormalities in post-EHA rehabilitation phase. EAAs enhance hip function retrieval and improve plasma amino acid abnormalities.

Unaffected arm muscle hypercatabolism in dysphagic subacute stroke patients: the effects of essential amino acid supplementation.

Alterations in muscle protein turnover of the unaffected side of stroke patients could contribute to physical disability. We investigated whether hypercatabolic activity occurred in unaffected arm muscle and whether supplemented essential amino acids (EAAs) could limit muscle hypercatabolism (MH). Thirty-eight dysphagic subacute stroke subjects (<3 months after acute event) (29 males+9 females; 69.7±11.4 yrs) were enrolled and randomized to receive 8 g/day EAAs (n=19; EAA group) or isocaloric placebo (maltodextrin; n=19, Plac group). Before randomization, all patients had their arterial (A) and venous (V) amino acids measured and muscle (A-V) differences calculated in the unaffected arm. Eight matched and healthy subjects served as controls. When compared to healthy controls, the entire stroke population showed significant muscle release (=negative value A-V) of the amino acid phenylalanine (phenyl-) indicating a prevalence of MH. Moreover, randomized EAA and Plac groups had similar rates of MH. After 38 days from the start of the protocol, the EAA group but not the Plac group had MH converted to balanced protein turnover or anabolic activity. We concluded that muscle protein metabolism of the unaffected arm of dysphagic subacute stroke individuals could be characterized by MH which can be corrected by supplemented EAAs.

Essential amino acids and exercise tolerance in elderly muscle-depleted subjects with chronic diseases: a rehabilitation without rehabilitation?

Exercise intolerance remains problematic in subjects with chronic heart failure (CHF) and/or chronic obstructive pulmonary disease (COPD). Recent studies show that supplemented essential amino acids (EAAs) may exert beneficial effects on CHF/COPD physical capacity. The results from 3 investigations (2 conducted on CHF and 1 on COPD subjects) served as the basis for this paper. The 3 studies consistently showed that elderly CHF and COPD improved exercise intolerance after 1-3 months of EAA supplementation (8 g/d). In CHF exercise capacity increased 18.7% to 23% (watts; bicycle test), and 12% to 22% (meters) in 6 min walking test. Moreover, patients reduced their resting plasma lactate levels (by 25%) and improved tissue insulin sensitivity by 16% (HOMA index). COPD subjects enjoyed similar benefits as CHF ones. They increased physical autonomy by 78.6% steps/day and decreased resting plasma lactate concentrations by 23%. EAA mechanisms explaining improved exercise intolerance could be increases in muscle aerobic metabolism, mass and function, and improvement of tissue insulin sensitivity (the latter only for the CHF population). These mechanisms could be accounted for by EAA's intrinsic physiological activity which increases myofibrils and mitochondria genesis in skeletal muscle and myocardium and glucose control. Supplemented EAAs can improve the physical autonomy of subjects with CHF/COPD.

Supplementation of essential amino acids may reduce the occurrence of infections in rehabilitation patients with brain injury.

BACKGROUND: To investigate whether supplementation with oral essential amino acids (EAAs) may reduce the occurrence of nosocomial infection among patients with brain injury (BI: stroke, trauma, anoxic coma). METHODS: Patients (n = 125; 77 men, 48 women; mean age 63 ± 15 years) with stroke (68.8%), subarachnoid hemorrhage (17.6%), traumatic BI (7.2%), and anoxic BI (6.4%) 88 ± 15 days after the index event. Patients were randomly assigned to 2 months of oral EAAs (n = 63; 8 g/d) or placebo (n = 62). RESULTS: Over the first month of rehabilitation, there were 60 infections in the whole population of 125 patients (48%); however, the rate was 23.2% lower in the EAA group (23 episodes/63 patients; 36.5%) than in the placebo group (37 episodes/62 patients; 59.7%) (P < .01). The types of infection were similarly distributed between the 2 groups. Serum levels of prealbumin <20 mg/dL and C-reactive protein (CRP) >0.3 mg/dL were the best predictors of future infection (prealbumin: odds ratio [OR] = 4.17, confidence interval [CI] 1.84-9.45, P < .001; CRP: OR = 3.8, CI 1.71-8.44, P < .001). CONCLUSION: Supplementary EAAs may reduce the occurrence of nosocomial infections in rehabilitation patients with BI. Prealbumin and CRP are the best predictors of future infections.

Effects of oral amino acid supplementation on long-term-care-acquired infections in elderly patients.

The very high general infection rate (IRI) observed in our Geriatric Intensive Rehabilitation Center (GIRC) led us to investigate whether patient supplementation with essential amino acids (EAAs), modulators of immuno-competence, could reduce IRI. Eighty elderly patients admitted to our GIRC (n=40; age 79.5 ± 7.71; male/female 14/26) or placebo (n=40; age 82.13 ± 6.15; male/female 13/27) were allocated to an 8 g/day oral EAAs group and were surveyed for infections (>48 h from admission) over the first month of their hospital stay. The IRI was 67% for the entire population of patients, 82.5% (33/40 patients) in the placebo group and 52% (21/40 patients) in the EAA group (p<0.02). When patients were divided into infection group (IG) and without-infection group (WIG), independently of post randomization allocation, the WIG had higher levels of serum albumin (p<0.001), blood hemoglobin (Hb) concentration (p=0.01), dietary protein (p=0.008) calorie intakes (p=0.05) but lower serum C-reactive protein (CRP) (p<0.001). The factor of CRP>0.8 mg/dl and Hb ≤ 12 in females, ≤13 in males was associated 4 times and 3.6 times risk of infection, respectively, by sex. EAAs supplementation may lower the risk of infection by 30% in the rehabilitative elderly population. CRP and blood hemoglobin levels can be considered risk markers of future infection.

Normalization of zinc intake enhances neurological retrieval of patients suffering from ischemic strokes.

INTRODUCTION: The objective of this study was to investigate whether zinc (Zn2+) supplementation could contribute to neurological retrieval of patients suffering from strokes and low Zn2+ intake. PATIENTS AND METHODS: Twenty-six patients with subacute stroke, having adequate daily energy (> or = 24 kcal/kg/day) and protein (> or = 0.8 g/kg/day) intake (EPI) and Zn2+ ingestion lower than two-thirds of the recommended allowance of 10 mg/day, were randomly allocated either to a control group (n = 13) or Zn2+ group (n = 13) where Zn2+ supplementation consisted of 10 mg Zn2+/day. Neurological gravity was tested with the NIH stroke scale (NIHSS) at patient admission and after 30 days of protocol commencement. RESULTS: At day 30, the improvement in NIHSS was higher in the zinc group than in the placebo (-4.7 +/- 1.3 points versus -3.3 +/- 1.1 points; P < 0.02). NIHSS and Zn2+ intake were negatively correlated (r = -0.46; P < 0.02). CONCLUSION: The normalization of Zn2+ intake in stroke patients with low mineral intake may enhance neurological recovery.

Protein supplementation may enhance the spontaneous recovery of neurological alterations in patients with ischaemic stroke.

OBJECTIVE: To determine whether protein supplementation could enhance neurological recovery in subacute patients with ischaemic stroke. DESIGN: Alimentation-independent patients with ischaemic stroke were randomly allocated to either 21 days of protein supplementation (protein-supplemented group; n=20) or to a spontaneous diet only (control group; n=21) in order to investigate the recovery of neurological changes (measured using the National Institute of Health (NIH) Stroke Scale). SETTING: Tertiary care rehabilitation in Italy. PARTICIPANTS: Forty-two patients (27 male and 15 female; 66.4 +/- 11 years) 16 +/-2 days after the acute event. INTERVENTION: Supplementation with a hyperproteic nutritional formula (10% protein). MAIN OUTCOME MEASURES: NIH Stroke Scale and protein intake. RESULTS: At admission to rehabilitation, both groups of patients were homogeneous for demographic, clinical and functional characteristics. After 21 days from the start of the protocol, the NIH Stroke Scale was found to be enhanced in the group with supplemental proteins (-4.4 +/- 1.5 score versus -3 +/- 1.4 of control group; P<0.01). When expressed as difference (triangle up) between baseline and 21 days, the NIH Stroke Scale correlated negatively with change in protein intake (g/day) (r=-0.50, P= 0.001) and positively with change in carbohydrate/protein ratio (r = +0.40, P=0.01) CONCLUSIONS: Protein supplementation may enhance neurological recovery in subacute patients with ischaemic stroke.

Branched-chain amino acids may improve recovery from a vegetative or minimally conscious state in patients with traumatic brain injury: a pilot study.

OBJECTIVE: To investigate whether supplementation with branched-chain amino acids (BCAAs) may improve recovery of patients with a posttraumatic vegetative or minimally conscious state. DESIGN: Patients were randomly assigned to 15 days of intravenous BCAA supplementation (n=22; 19.6g/d) or an isonitrogenous placebo (n=19). SETTING: Tertiary care rehabilitation setting. PARTICIPANTS: Patients (N=41; 29 men, 12 women; mean age, 49.5+/-21 y) with a posttraumatic vegetative or minimally conscious state, 47+/-24 days after the index traumatic event. INTERVENTION: Supplementation with BCAAs. MAIN OUTCOME MEASURE: Disability Rating Scale (DRS) as log(10)DRS. RESULTS: Fifteen days after admission to the rehabilitation department, the log(10)DRS score improved significantly only in patients who had received BCAAs (log(10)DRS score, 1.365+/-0.08 to 1.294+/-0.05; P<.001), while the log(10)DRS score in the placebo recipients remained virtually unchanged (log(10)DRS score, 1.373+/-0.03 to 1.37+/-0.03; P not significant). The difference in improvement of log(10)DRS score between the 2 groups was highly significant (P<.000). Moreover, 68.2% (n=15) of treated patients achieved a log(10)DRS point score of .477 or higher (3 as geometric mean) that allowed them to exit the vegetative or minimally conscious state. CONCLUSIONS: Supplemented BCAAs may improve the recovery from a vegetative or minimally conscious state in patients with posttraumatic vegetative or minimally conscious state.

Oral amino acid supplements improve exercise capacities in elderly patients with chronic heart failure.

We investigated whether 30 days of oral supplementation with a special mixture of amino acids (AAs), together with conventional therapy, could improve exercise capacity in elderly outpatients with chronic heart failure (CHF). A group of 95 outpatients (12 women and 83 men; New York Heart Association class II-III) aged 65-74 years were studied. This was a randomized, double-blind, placebo-controlled study. The patients performed a basal exercise test and were then randomly assigned to a special oral nutritional mixture of AAs 4 g twice daily (n = 43) or placebo (n = 42). After 30 days we repeated the exercise test. In both tests we measured the following: oxygen consumption (VO2), CO2 production (VCO2), minute ventilation (VE), oxygen cost of ventilation (VO2/VE), CO2 elimination per liter of ventilation (VCO2/VE), respiratory exchange ratio (RER; calculated as VCO2/VO2), oxygen pulse (VO2/heart rate [HR]) and anaerobic metabolism during exercise (ANA-VO2). At day 30, exercise capacity in the AA group had improved (+11 +/- 8 W, p <0.01; +67.5 +/- 44 seconds, p <0.02). This improvement was associated with both reduced circulatory dysfunction and increased peripheral oxygen availability. Indeed, peak VO2 increased by 1.2 +/- 1.1 mL/kg per min (+12.7% +/- 13%; p<0.02) and VO2/HR improved by 1.5 +/- 1.4 mL O2 per heartbeat (p <0.05). ANA-VO2 was reduced by >50% in patients on AAs (from 20.2 +/- 10 mL/kg at day 0 to 10.9 +/- 5 mL/kg at day 30; p <0.02). These variables did not significantly change for patients who received placebo. In conclusion, the study showed that oral AA supplementation, in conjunction with standard pharmacologic therapy, appears to increase exercise capacity by improving circulatory function, muscle oxygen consumption, and aerobic production of energy in elderly outpatients with CHF.

Branched-chain amino acids enhance the cognitive recovery of patients with severe traumatic brain injury.

OBJECTIVE: To investigate whether supplementation with branched-chain amino acids (BCAAs) in patients with severe traumatic brain injury (TBI) improves recovery of cognition and influences plasma concentrations of tyrosine and tryptophan, which are precursors of, respectively, catecholamine and serotonin neurotransmitters in the brain. DESIGN: Forty patients with TBI were randomly assigned to 15 days of intravenous BCAA supplementation (19.6g/d) (n=20) or an isonitrogenous placebo (n=20). SETTING: Tertiary care rehabilitation setting in Italy. PARTICIPANTS: Forty men (mean age, 32+/-15 y) with TBI and 20 healthy subjects (controls) matched for age, sex, and sedentary lifestyle. INTERVENTION: Supplementation with BCAAs. MAIN OUTCOME MEASURES: Disability Rating Scale (DRS) and plasma concentrations of BCAAs, tyrosine, and tryptophan. RESULTS: Fifteen days after admission to the rehabilitation department, the DRS score had improved significantly in both the placebo group (P<.05 vs baseline) and in the BCAA-supplemented group (P<.01 vs baseline). The difference between the 2 groups was significant (P<.004). Plasma tyrosine concentration improved in the group given BCAA supplementation, and tryptophan concentration increased in patients receiving placebo. CONCLUSIONS: Supplemental BCAAs enhance the retrieval of DRS without causing negative effects on tyrosine and tryptophan concentration.