Is stroke rehabilitation a metabolic problem?

Optimizing acute stroke outcome prediction models: Comparison of generalized regression neural networks and logistic regressions

Background

Generalized regression neural network (GRNN) and logistic regression (LR) are extensively used in the medical field; however, the better model for predicting stroke outcome has not been established. The primary goal of this study was to compare the accuracies of GRNN and LR models to identify the most optimal model for the prediction of acute stroke outcome, as well as explore useful biomarkers for predicting the prognosis of acute stroke patients.

Method

In a single-center study, 216 (80% for the training set and 20% for the test set) acute stroke patients admitted to the Shenzhen Second People’s Hospital between December 2019 to June 2021 were retrospectively recruited. The functional outcomes of the patients were measured using Barthel Index (BI) on discharge. A training set was used to optimize the GRNN and LR models. The test set was utilized to validate and compare the performances of GRNN and LR in predicting acute stroke outcome based on the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, and the Kappa value.

Result

The LR analysis showed that age, the National Institute Health Stroke Scale score, BI index, hemoglobin, and albumin were independently associated with stroke outcome. After validating in test set using these variables, we found that the GRNN model showed a better performance based on AUROC (0.931 vs 0.702), sensitivity (0.933 vs 0.700), specificity (0.889 vs 0.722), accuracy (0.896 vs 0.729), and the Kappa value (0.775 vs 0.416) than the LR model.

Conclusion

Overall, the GRNN model demonstrated superior performance to the LR model in predicting the prognosis of acute stroke patients. In addition to its advantage in not affected by implicit interactions and complex relationship in the data. Thus, we suggested that GRNN could be served as the optimal statistical model for acute stroke outcome prediction. Simultaneously, prospective validation based on more variables of the GRNN model for the prediction is required in future studies.

State of the science in inflammation and stroke recovery: A systematic review

Stroke is a major cause of mortality worldwide, and survivors often have major life-changing disabilities. Annually in the United States, an estimated 795,000 people experience a new or recurrent stroke. All types of stroke involve an inflammatory reaction that follows the initial phase of incidence. However, investigations into any links between inflammatory markers and recovery processes in the context of post-stroke rehabilitation are lacking. In this systematic review, we searched the literature in PubMed, SCOPUS, and CINAHL databases to gather information on inflammatory biomarkers related to stroke and their association with rehabilitation outcomes, according to PRISMA guidelines. Eleven articles (n=1.773 stroke patients) were selected. Immune markers (interleukin 6 [IL-6], C-reactive protein, IL-1α, tumor necrosis factor α, soluble intercellular adhesion molecule 1) and functional status assessments (Modified Rankin Score, National Institutes of Health Stroke Scale, Functional Independence Measure, etc.) were the primary measures used in the reviewed studies. We found preliminary evidence for the evaluation of inflammatory biomarkers post-stroke, including the role of inflammation in functional recovery and the influence of rehabilitation on inflammation. This is the first systematic review of the topic. The review identifies several gaps in the literature that are critical for understanding the potential use of inflammatory markers to improve post-stroke outcomes.

Essential amino acid supplementation is associated with reduced serum C-reactive protein levels and improved circulating lymphocytes in post-acute inflamed elderly patients

Background

Persistent systemic inflammation leads to multidistrectual body dysfunctions. Attenuation of inflammation may improve patients’ functional and life prognoses. We hypothesized that essential amino acids (EAAs) given to elderly patients in rehabilitation after acute diseases may be associated with a reduced inflammatory state. Therefore, this retrospective study investigated whether the supplementation of EAAs – modulators of immune competence – was associated with a reduced inflammation rate in elderly patients.

Methods

The medical records of 282 patients admitted to the rehabilitation (rehab) institute after acute index events (surgery or medical diseases) (age: 81.18 ± 8.58 years; females: 67.9%) were analyzed.

Results

46 patients (16.3% of the entire population) had received EAA supplements (S), whereas the remaining 236 patients had not (N-S). Systemic inflammation (I) (serum C-reactive protein (CRP) > 0.5 mg/dL) was present in 67.4% of the I-S group and 57.2% of the I-N-S group. During rehab, the I-S group (but not the I-N-S group) showed a reduction in CRP levels (p = 0.03) and an increase in circulating lymphocytes (p = 0.035), immune cells of the adaptive immune system. C-reactive protein levels remained virtually unchanged in non-inflamed patients who received supplements but increased in non-inflamed patients who did not receive supplements (p = 0.05). Stratified for developed infections, CRP levels reduced in S patients (p = 0.008) but did not in N-S patients.

Conclusion

EAA supplementation was associated with reduced inflammation in both inflamed and infected patients. In addition, EAA supplementation was associated with increased circulating lymphocytes in inflamed patients.

The relationship between plasma amino acids and circulating albumin and haemoglobin in postabsorptive stroke patients

Background

This retrospective study had two main aims: (1) to document possible correlations between plasma Amino Acids (AAs) and circulating Albumin (Alb) and Haemoglobin (Hb); and (2) to identify which AAs were predictors of Alb and Hb.

Methods

The study considered 125 stroke subjects (ST) (61.6% males; 65.6 +/- 14.9 years) who met the eligibility criteria (absence of co morbidities associated with altered plasma AAs and presence of plasma AAs determined after overnight fasting). Fifteen matched healthy subjects with measured plasma AAs served as controls.

Results

The best correlations of Alb were with tryptophan (Trp) and histidine (His) (r = + 0.53; p < 0.0001), and those of Hb were with histidine (r = +0.47) and Essential AAs (r = +0.47) (both p<0.0001). In multivariate analysis, Trp (p< 0.0001) and His (p = 0.01) were shown to be the best positive predictors of Alb, whereas glutamine (p = 0.006) was the best positive predictor of Hb.

Conclusions

The study shows that the majority of plasma AAs were positively correlated with Alb and Hb. The best predictors of circulating Alb and Hb were the levels of tryptophan and glutamine, respectively.

Inflammation and rehabilitation outcomes in patients with nontraumatic intracranial haemorrhage

BACKGROUND

Systemic inflammation and its impact on rehabilitation for patients with non-traumatic haemorrhagic injury (HBI) sequelae has not yet been adequately documented.

OBJECTIVE AND METHODS

We therefore considered 31 patients with HBI, to determine the serum levels of inflammatory markers (C-Reactive Protein, CRP and or interleukine-6, IL-6) to establish their impact on functional status (Functional Independence Measure, FIM: 18 indicating the worst performance and 126, a normal score).

RESULTS

The results showed an inflammation prevalence (CRP >0.5 mg/dl and/or IL 6 >7 pg/ml) of 74.2% at admission to Rehab. FIM reduction was more pronounced in inflamed compared to non-inflamed subjects (p <  0.05) and significantly correlated with blood variables sensitive to inflammation, such as alpha 1 globulin (r = - 0.565) and neutrophil/ lymphocyte ratio (r = - 0.52), CRP (r = - 0.365). At discharge from Rehab, the inflammation rate diminished. Inflamed patients showed similar gains in FIM score as their controls. In the entire population, the FIM gain was significantly associated with a gain in serum albumin, only (r = +0.56).

CONCLUSIONS

We conclude that systemic inflammation is prevalent in HBI patients and contributes to reduce patient functional status. However, during the Rehab stage, inflammation does not hinder the improvement rate of functional capacity.

Inflammation and rehabilitation outcomes in patients with nontraumatic intracranial haemorrhage

BACKGROUND

Systemic inflammation and its impact on rehabilitation for patients with non-traumatic haemorrhagic injury (HBI) sequelae has not yet been adequately documented.

OBJECTIVE AND METHODS

We therefore considered 31 patients with HBI, to determine the serum levels of inflammatory markers (C-Reactive Protein, CRP and or interleukine-6, IL-6) to establish their impact on functional status (Functional Independence Measure, FIM: 18 indicating the worst performance and 126, a normal score).

RESULTS

The results showed an inflammation prevalence (CRP >0.5 mg/dl and/or IL 6 >7 pg/ml) of 74.2% at admission to Rehab. FIM reduction was more pronounced in inflamed compared to non-inflamed subjects (p <  0.05) and significantly correlated with blood variables sensitive to inflammation, such as alpha 1 globulin (r = - 0.565) and neutrophil/ lymphocyte ratio (r = - 0.52), CRP (r = - 0.365). At discharge from Rehab, the inflammation rate diminished. Inflamed patients showed similar gains in FIM score as their controls. In the entire population, the FIM gain was significantly associated with a gain in serum albumin, only (r = +0.56).

CONCLUSIONS

We conclude that systemic inflammation is prevalent in HBI patients and contributes to reduce patient functional status. However, during the Rehab stage, inflammation does not hinder the improvement rate of functional capacity.

Plasma energy substrates at two stages of Alzheimer’s disease in humans

In Alzheimer’s disease (AD), the presence of amyloid-β peptide may impair cell energy formation by altering both anaerobic and aerobic metabolism. This study aimed to estimate possible alterations in circulating energy substrates. In 54 community-dwelling AD subjects, fasting peripheral venous blood samples were drawn in the morning to determine the energy substrates lactate, pyruvate and ketone bodies (KBs, β-hydroxybutyrate and acetoacetate). Plasma lactate levels in the entire AD population were significantly lower than in healthy controls (P < 0.01), whereas pyruvate concentrations were similar. This is particularly evident in AD subjects with diagnosis time  >5 years. Moreover, both plasma lactate and pyruvate were lower in subjects with AD >5 years than in subjects with AD ⩽5 years (P < 0.001 for lactate; P = 0.04 for pyruvate). KB concentrations were normal in both subgroups. Lactate was inversely related to diagnosis time (r = −0.42; P = 0.002). In conclusion, subjects with AD, particularly those with a longer diagnosis time, show considerable reductions in circulating lactate and pyruvate as an expression of altered muscular metabolic pathways that generate energy.

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.

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.