Sara Missaglia

Mutations in the PNPLA2 gene, which encodes adipose triglyceride lipase (ATGL), are linked to neutral lipid storage disease with myopathy (NLSDM). This rare genetic disorder is marked by abnormal accumulation of neutral lipids in cytoplasmic lipid droplets, leading to muscle-related symptoms such as weakness, cramps and progressive myopathy in almost all patients, and cardiomyopathy in about half of the patients. Here, we report a novel PNPLA2 variant and the clinical and MRI findings of a 42-year-old Italian male with NLSDM, revealing a myopathic pattern involving both proximal and distal muscles of all four limbs, as well as axial and facial muscles, without detectable cardiac abnormalities. Genetic testing uncovered a novel PNPLA2 homozygous mutation, resulting in the deletion of a single amino acid in the first ATGL LC3-interacting region (LIR) motif. In addition, bioinformatic analyses predicted changes in mutated ATGL’s structure that could affect its enzymatic function and impair both lipolysis and lipophagy by disrupting ATGL-LC3 interaction. Western blot analysis confirmed a block in lipophagic flux. This study broadens our understanding of the genetic and clinical heterogeneity of NLSDM, highlighting the complexity of the disease.

Background: Adiponectin is an adipokine with insulin-sensitizing, anti-inflammatory, and cytoprotective properties that also plays a key role in metabolic adaptation to exercise. Although its regulation after resistance exercise has been extensively documented, less is known about its short-term modulation and its correlation with muscle damage markers following resistance training. Methods: Nine resistance-trained young men completed two sessions of total-body resistance exercise: (1) high time under tension (TUT) (5-1-2-1 cadence, to failure; ETS1) and (2) moderate TUT (2-1-2-1 cadence, two repetitions in reserve; ETS2). Plasma and saliva samples were collected before exercise and at 15 min, 24 h, and 48 h after exercise to assess total adiponectin by ELISA. Plasma creatine kinase (CK) and a Visual Analog Scale (VAS) were also measured for muscle soreness. Results: Plasma adiponectin significantly decreased from baseline to 48 h post-exercise in both sessions (p < 0.001), with no differences between the TUT conditions. Salivary adiponectin remained unchanged. Although a significant increase in CK and a decrease in adiponectin were observed at the group level, correlation analysis revealed no significant linear relationship between the magnitude of CK elevation and adiponectin reduction. Conclusions: Overall, these findings support the role of adiponectin as a marker of acute metabolic adaptation to resistance exercise. Acute resistance exercise elicited a time-dependent decrease in circulating adiponectin, irrespective of TUT. The temporal pattern of adiponectin decrease coincided with the rise in muscle damage markers, yet the lack of direct correlation suggests distinct regulatory mechanisms, while the lack of salivary changes underscores the complexity of adipokine regulation in vivo and suggests that saliva is not a reliable indicator of changes in circulating adiponectin.

Irisin’s response to Resistance Exercise (RE) remains unclear. We investigated plasma and salivary irisin levels following acute moderate load/high volume (ML/HV) RE and explored correlations with muscle damage markers. Eight healthy, resistance-trained young males (23.3±2.5 yrs) completed one ML/HV RE session (full-body, 30 sets to failure, 70% 1RM). Plasma/saliva irisin, plasma Creatine Kinase (CK), and Visual Analogue Scale (VAS) for muscle soreness were assessed at baseline, 15 min, 24h, and 48h post-exercise. Plasma irisin increased significantly by ~9% (p=0.01) and salivary irisin by ~4% (p=0.02) at 15 min post-exercise, returning towards baseline by 24h. A strong correlation (rho=0.8, p=0.03) existed between percentage changes in plasma and salivary irisin at 15 min. CK and VAS peaked at 24h (p<0.001; p=0.02 vs 48h, respectively), but showed no significant correlation with irisin changes. Acute ML/HV RE elicits a transient increase in plasma and salivary irisin. Saliva may be a useful non-invasive proxy for irisin changes post-RE. This acute irisin response appears independent of EIMD markers in this population. Findings require confirmation in larger studies.

BACKGROUND: Morbidity and mortality of heart failure with preserved ejection fraction (HFpEF) is increased in metabolic disorders. However, options for preventing and treating these prevalent outcomes are limited. Intramyocardial lipotoxicity contributes to cardiac dysfunction. Here, we investigate the mechanisms underlying EDEM2 (endoplasmic reticulum degradation–enhancing alpha-mannosidase–like protein 2) regulation of cardiac lipid homeostasis and assess strategies that inhibit the incidence and progression of HFpEF. METHODS: Metabolic stress was induced in C57BL/6 male mice using a high-fat diet and N ω-nitro-L-arginine methyl ester. The recombinant adeno-associated virus 9 delivery system was used for loss- and gain-of-function studies. Palmitic acid and oleic acid stimulation of rat cardiomyocytes and human induced pluripotent stem cell–derived cardiomyocytes imitated a condition of high lipids in vitro. Molecular mechanisms were investigated via RNA sequencing, mass spectrometry proteomics, lipidomic analyses, transmission electron microscopy, histology, and luciferase reporter assays. RESULTS: In the human heart, we first detected lipid overload accompanied by a reduction of XBP1 (X-box binding protein 1) under metabolic stress. Thereafter, a decrease in EDEM2 was confirmed in human and mouse HFpEF hearts. Given that XBP1s (spliced X-box binding protein 1) is a transcription factor, EDEM2 was identified as its new target in cardiomyocytes. EDEM2 knockdown mice manifested lipid droplet accumulation and higher levels of triglycerides and diglycerides in the myocardium, aggravating oxidative stress, hypertrophy, and the onset and progression of HFpEF under metabolic stress. XBP1s ablation mice displayed a similar myocardial lipid disturbance and cardiac phenotypes, which were reversed by EDEM2 overexpression. Mechanistically, the findings obtained from rat cardiomyocytes and human induced pluripotent stem cell–derived cardiomyocytes demonstrated that, in the presence of EDEM2, SEC23A mediated intracellular translocation of ATGL (adipose triglyceride lipase) under fatty acid stimulation, inhibiting ATGL degradation and excessive intracellular lipid droplets. Furthermore, the functional studies supported that EDEM2 prevention of lipid overload occurred in an ATGL-dependent manner. Therapeutically, cardiac XBP1s or EDEM2 restoration mitigated lipid deposition and preserved lipid profiles in the myocardium, thus preventing the development of HFpEF. CONCLUSIONS: We demonstrate a cardioprotective mechanism regulating myocardial lipid homeostasis. The findings provide a promising therapeutic target to prevent and treat HFpEF, a condition with limited treatment options.

Purpose: This study aimed to investigate the time course of β-endorphin (β-EDP) levels in healthy males following an acute exercise, while considering their age and physical fitness (PF) level. Methods: Participants (N = 29, 20–65 years) were categorized in good PF young adult (YA1), excellent PF young adult (YA2), and excellent PF middle-aged adult (MA) group, depending on peak oxygen uptake and age. They underwent a maximal incremental cycling test, with blood samples collected at baseline (T0), 15 min (T1), and 24 h post-exercise (T2). Serum β-EDP levels were measured using an ELISA kit. Results: Significant increases in β-EDP levels were observed from T0 to T1 in all enrolled subjects. In YA1, levels rose from 170.1 to 202.5 pg/ml (p < 0.001), in YA2 from 188.4 to 230.3 pg/ml (p < 0.05), and in MA level increased from 153 to 189.3 pg/ml (p < 0.01). YA2 showed higher levels of β-EDP than MA in any time point (p < 0.05). All groups displayed a significant decrease of β-EDP from T1 to T2. Comparison between groups revealed that age significantly influenced baseline β-EDP levels, with notable differences between young and middle-aged individuals. Noteworthy, MA with excellent PF presented similar β-EDP levels to young with good PF. Conclusion: Acute exercise triggers a notable but transient elevation of serum β-EDP levels in both young and middle-aged adults, with the latter exhibiting lower baseline levels. Additionally, our findings suggest that age may have a greater influence on β-EDP secretion, both at rest and after physical exercise compared to PF level.

Physical activity promotes metabolic health and prevents lifestyle-related diseases. Adiponectin is specifically produced by adipose tissue and comes in three forms, differing in terms of weight: trimers (LMW), hexamers (MMW), and high-molecular-weight (HMW) oligomers. The oligomers are associated with the beneficial effects of adiponectin. In this study, we aimed to investigate the impact of a single bout of exhaustive exercise on adiponectin expression in 25 male amateur athletes, divided into two groups, one comprising young adults (YAs) (n = 15), and the other comprising middle-aged adults (MAs) (n = 10). Body fat was estimated through skinfold thickness. Adiponectin levels were assessed at baseline and at 15 min and 24 h post-exercise, while HMW oligomer levels were evaluated at baseline and at 24 h post-exercise. We observed a significant increase in total adiponectin at both 15 min and 24 h after exercise, with there being a more evident effect among the YA subjects. HMW oligomers also increased significantly after exercise both in the total sample and among the YA subjects, but this was not the case in the MA subjects. The increase in adiponectin levels was significantly associated with Power_peak. Furthermore, a significant inverse correlation was found between basal adiponectin and VO_2peak and Power_peak. In conclusion, a single bout of exhaustive exercise can rapidly and significantly enhance the basal circulating adiponectin concentration, which seems to be negatively associated with maximal aerobic capacity.

This study aimed to analyze the acute impact of exercise on serum irisin levels in 22 young (YA, 24.6 ± 3.5 yrs) and in 12 middle-aged male adults (MA, 54.6 ± 5.7 yrs) 15 min and 24 h after an incremental cycling exercise test to exhaustion. ELISA assay was used for serum irisin detection. Circulating irisin increased significantly from baseline (9.0 ± 2.0 ng/ml) to 15 min post-exercise (10.2 ± 2.0 ng/ml, P < 0.001), but the greatest increment was detected after 24 h (13.5 ± 2.5 ng/ml, P < 0.001) reaching more than 50% of the basal release. Levels were significantly higher in YA (9.7 ± 1.7 to 11.1 ± 1.8 to 14.5 ± 2.2 ng/ml) than MA (7.6 ± 1.6 to 8.7 ± 1.5 to 11.8± 2.2 ng/ml) for all measured time-points (P < 0.05). Nevertheless, MA showed a comparable increase in serum irisin levels when compared to YA. These findings highlight the importance of acute physical exercise as a countermeasure against age-related deterioration of skeletal muscle mass and function in both YA and MA.

Adipose tissue is mainly composed by adipocytes. Moreover, mesenchymal stromal/stem cells (MSCs), macrophages, endothelial cells, and extracellular matrix components are present. The variety of molecules as cytokines and growth factors of its structure very rich in blood vessel makes it also similar to a true endocrine organ that however needs still to be fully investigated. In our study, we used human lipoaspirate to obtain mechanically microfragmented fat (MiFAT) which was washed and then devitalized by freezing–thawing cycles. In our experiments, thawed MiFAT was used to stimulate cultures of MSCs from two different sources (adipose tissue and gingiva papilla) in comparison with a traditional stimulation in vitro obtained by culturing MSCs with adipogenic medium. MSCs stimulated with MiFAT showed a very early production of lipid droplets, after only 3 days, that correlated with an increased expression of adipokines. Furthermore, a significant upregulation of PPAR gamma 1 alpha coactivator (PPARGC1A) was observed with an overexpression of uncoupling protein 1 (UCP1) that suggest a pattern of differentiation compatible with the beige–brown fat.