Chest CT Radiomics is Feasible in Evaluating Muscle Change in Diabetes Patients

BACKGROUND

Non-invasive imaging methods are still lacking for the evaluation of muscle changes in diabetes.

PURPOSE

To investigate the feasibility of muscle CT radiomics in evaluating muscle changes in diabetes.

MATERIALS AND METHODS

60 diabetics and 60 health controls (HC) were assessed with the method of muscle CT radiomics. 93 CT images of radiomics features of the pectoralis major muscle (PMM) were obtained by using the software 3D Slicer and were then compared between diabetics and HC cases. The least absolute shrinkage and selection operator (LASSO) regression method was used to establish a prediction model. The receiver operating characteristic (ROC) curve was used to determine the performance of the model.

RESULTS

Diabetics and HC cases differed in 19 radiomics features (P<0.05). By using the LASSO method, 6 features were finally selected. The AUC of the model in the discrimination of diabetics and HC were 0.92 and 0.90, respectively, for the training cohort and validation cohort.

CONCLUSION

Muscle CT radiomics is feasible in evaluating muscle changes in diabetes.

Sarcopenia in Persons Living with HIV under Antiretroviral Therapy: Literature Review

The epidemiological profile of people living with HIV (PLWH) has expressively changed since the introduction of antiretroviral therapy (ART), from a high mortality rate to a profile similar to those living with chronic diseases. Despite the advances and effectiveness of ART, there are still various challenges to overcome, and we highlight the increased risk of sarcopenia in PLWH. This review study aims to (i) explore the pathophysiological background of sarcopenia in PLWH under the different existing ART and (ii) develop a mini-systematic review searching epidemiological studies investigating sarcopenia prevalence in PLWH. As our main findings: we established the risk of sarcopenia development, under a sequential path involving HIV, ART, immune activation, low-grade systemic inflammation, metabolic disorders, and changes in protein synthesis and breakdown in skeletal muscle tissue; some ART drugs, mainly reverse transcriptase inhibitors and protease inhibitors, contribute to critical metabolic changes, lowering the autophagy, increasing mitochondrial dysfunction and insulin resistance, which favor the development of inflammation and muscle protein breakdown. There is still insufficient data to discuss the effects of the new generation drugs, namely integrase inhibitors and fusion inhibitors, on skeletal muscle. More studies are needed to better clarify these relationships.

Acute ischemic preconditioning does not influence high-intensity intermittent exercise performance

This study evaluated the acute effect of ischemic preconditioning (IPC) on a high-intensity intermittent exercise performance and physiological indicators in amateur soccer players. Thirteen players (21.5 ± 2 yrs) attended three trials separated by 3–5 days in a counterbalanced randomized cross-over design: IPC (4 × 5-min occlusion 220 mmHg/reperfusion 0 mmHg) in each thigh; SHAM (similar to the IPC protocol but “occlusion” at 20 mmHg) and control (seated during the same time of IPC). After 6-min of each trial (IPC, SHAM or control), the players performed the YoYo Intermittent Endurance Test level 2 (YoYoIE2). The distance covered in the YoYoIE2 (IPC 867 ± 205 m; SHAM 873 ± 212 m; control 921 ± 206 m) was not different among trials (p = 0.10), furthermore, lactate concentration and rate of perceived exertion did not differ (P > 0.05) among protocols. There were also no significant differences in either mean heart rate (HR) or peak HR (p > 0.05) for both IPC and SHAM compared to control. Therefore, we conclude that acute IPC does not influence high-intensity intermittent exercise performance in amateur soccer players and that rate of perceived exertion, heart rate and lactate do not differ between the intervention IPC, SHAM and control.

Skeletal Muscle Mitochondrial Function and Fatigability in Older Adults

BACKGROUND

Fatigability increases while the capacity for mitochondrial energy production tends to decrease significantly with age. Thus, diminished mitochondrial function may contribute to higher levels of fatigability in older adults.

METHODS

The relationship between fatigability and skeletal muscle mitochondrial function was examined in 30 participants aged 78.5 ± 5.0 years (47% female, 93% white), with a body mass index of 25.9 ± 2.7 kg/m(2) and usual gait-speed of 1.2 ± 0.2 m/s. Fatigability was defined using rating of perceived exertion (6-20 point Borg scale) after a 5-minute treadmill walk at 0.72 m/s. Phosphocreatine recovery in the quadriceps was measured using (31)P magnetic resonance spectroscopy and images of the quadriceps were captured to calculate quadriceps volume. ATPmax (mM ATP/s) and oxidative capacity of the quadriceps (ATPmax·Quadriceps volume) were calculated. Peak aerobic capacity (VO2peak) was measured using a modified Balke protocol.

RESULTS

ATPmax·Quadriceps volume was associated with VO2peak and was 162.61mM ATP·mL/s lower (p = .03) in those with high (rating of perceived exertion ≥10) versus low (rating of perceived exertion ≤9) fatigability. Participants with high fatigability required a significantly higher proportion of VO2peak to walk at 0.72 m/s compared with those with low fatigability (58.7 ± 19.4% vs 44.9 ± 13.2%, p < .05). After adjustment for age and sex, higher ATPmax was associated with lower odds of having high fatigability (odds ratio: 0.34, 95% CI: 0.11-1.01, p = .05).

CONCLUSIONS

Lower capacity for oxidative phosphorylation in the quadriceps, perhaps by contributing to lower VO2peak, is associated with higher fatigability in older adults.

Skeletal muscle lipid content and oxidative activity in relation to muscle fiber type in aging and metabolic syndrome

One of the most noticeable effects of aging is the reduction in skeletal muscle mass and strength (sarcopenia). The metabolic syndrome (MS) is also prevalent in old subjects, but its relevance to skeletal muscle characteristics has poorly been investigated. Immunohistochemical studies were performed with muscle biopsies from young (22 years) and old (73 years) men with and without MS to reveal age-dependent and MS-associated modifications of fiber-type characteristics. Atrophy of type II fibers and altered fiber shape characterized muscle aging in lean healthy men. In contrast, increased cross-sectional area of the most abundant type I and type IIA fibers, and reduced cytochrome c oxidase content in all fiber types, characterized MS. Aging and particularly MS were associated with accumulation of intramyocellular lipid droplets. Although lipids mostly accumulated in type I fibers, matrix-assisted laser desorption/ionization-mass spectrometry imaging of intramyocellular lipids did not distinguish fiber types, but clearly separated young, old, and MS subjects. In conclusion, our study suggests that MS in the elderly persons is associated with alterations in skeletal muscle at a fiber-type specific level. Overall, these fiber type-specific modifications may be important both for the age-related loss of muscle mass and strength and for the increased prevalence of MS in elderly subjects.