Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 847
Filter
1.
Diabetes ; 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38968429

ABSTRACT

Insulin is a key regulator of amino acids (AAs) metabolism. Many plasma AAs, including lysine and its metabolite, α-aminoadipic acid (α-AA), a predictor for developing diabetes, are elevated in insulin resistance. In 18 insulin-resistant (IR) over-weight women with polycystic ovary syndrome compared to 12 lean controls, high physiological insulin during a euglycemic clamp failed to normalize many elevated AA metabolites, including branched-chain and aromatic AA, alphaamino- butyric acid, and lysine, but normalized α-AA. To understand the underpinning of differential responses of lysine and its metabolic product α-AA to high physiological insulin in IR compared to controls, we developed a kinetic model utilizing [α-15N1] lysine and [13C1] α-AA as tracers and measured the two tracers simultaneously in α-AA by innovative mass spectrometry. High insulin increased lysine conversion to α-AA in IR and controls but failed to normalize plasma lysine concentrations in IR due to a decrease in lysine metabolic clearance rate (MCR). In contrast, despite higher conversion rates of lysine to α-AA by high insulin, α-AA concentration decreased in IR because of the sustained greater MCR of α-AA. The abnormal AAs and metabolites, even while on high physiological insulin, could potentially explain many functional derangements in IR.

2.
Eur J Haematol ; 2024 May 28.
Article in English | MEDLINE | ID: mdl-38804098

ABSTRACT

BACKGROUND: Precursor plasma cell disorders such as monoclonal gammopathy of undetermined significance (MGUS) always precede the development of active malignancies such as multiple myeloma (MM). There is a need for novel biomarkers to identify those patients with such precursor plasma cell disorders who rapidly progress to MM. Plasma-derived extracellular vesicles (EVs) may serve as a reservoir of potential biomarkers that can shed light on the pathogenesis and disease biology of MM. METHODS: This study isolated small EVs (SEVs) and large EVs (LEVs) from the platelet-poor peripheral blood plasma of MGUS (n = 9) and MM (n = 12) patients using the size exclusion chromatography-based method and evaluated their proteome using a label-free proteomics workflow. RESULTS: In total, 2055 proteins were identified in SEVs, while 2794 proteins were identified in LEVs. The transferrin receptor (or CD71) protein was upregulated in both populations of EVs derived from MM patients compared to MGUS patients and was of prognostic significance. Similarly, three isoforms of serum amyloid A (SAA) protein, SAA1, SAA2, and SAA4, were also highly upregulated in SEVs within MM patients relative to MGUS patients. Finally, CD40 expression was also higher in the LEVs derived from MM patients than in MGUS patients. CONCLUSIONS: This study demonstrates the feasibility of successfully isolating both SEVs and LEVs from the peripheral blood of patients with plasma cell disorders and quantifying protein biomarkers within these EVs that could be of prognostic and diagnostic interest.

4.
Transfusion ; 64(3): 550-553, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38380495

ABSTRACT

BACKGROUND: Subcutaneous emphysema is a condition where air becomes trapped under the skin, typically resulting from surgery or skin trauma. It is mostly localized and its occurrence in blood donors is exceedingly rare. Phlebotomy poses minimal risk of subcutaneous emphysema, but procedural errors may lead to such complications. STUDY DESIGN AND METHOD: This is a case report of 29-year-old repeat blood donor who experienced subcutaneous emphysema following blood donation. The donor was vigorously squeezing sponge ball during donation resulting in displacement of the needle which required readjustment. Post-donation, the donor reported a crackling sensation and mild swelling near phlebotomy site. Non-contrast computed tomography (NCCT) scans confirmed subcutaneous emphysema, attributing its development to air trapping in subcutaneous plane due to ball valve mechanism. RESULTS: Computed tomography (CT) imaging revealed subcutaneous emphysematous changes in the right cubital region and no evidence of hematoma. The swelling spontaneously subsided in 10-12 days without any intervention. The case underscores the importance of differentiating subcutaneous emphysema from common complications like hematoma. DISCUSSION: Subcutaneous emphysema in blood donors is exceptionally rare but should be managed with clear communication. Donors should be reassured that the condition, although rare, is benign and self-resolving. Healthcare providers should be equipped to handle such rare complications, offering appropriate care and documenting incidents for future prevention.


Subject(s)
Blood Donation , Subcutaneous Emphysema , Humans , Adult , Subcutaneous Emphysema/diagnostic imaging , Subcutaneous Emphysema/etiology , Tomography, X-Ray Computed/adverse effects , Blood Donors , Hematoma/complications
5.
Article in English | MEDLINE | ID: mdl-38227797

ABSTRACT

Background: Insulin resistance can be present in otherwise healthy, normal weight adults. Whether there are phenotype/sex-differences between normal weight insulin-resistant (NWIR) and normal weight insulin-sensitive (NWIS) Caucasians and whether there are differences in adverse health outcomes are unknown. Our goal was to define phenotypes and intermediate-term health outcomes of NWIR versus NWIS Caucasian adults. Methods: We analyzed data from 227 healthy volunteers body mass index 18 to <25.0 kg/m2 who underwent insulin clamp studies between January 1987 and January 2017 at Mayo Clinic to identify those in the top (NWIS, n = 56) and bottom (NWIR, n = 56) quartiles of insulin action. We compared the phenotypical characteristics and were able to collect medical records data for 80% of NWIS and 88% of NWIR to identify time to onset of hypertension, hyperglycemia, coronary heart disease, cerebrovascular disease, peripheral vascular disease, and all cause death; the follow-up averaged 11 (4, 20) years. Results: Body fat was significantly greater and peak VO2 was significantly less in both NWIS than NWIR males and females. Only in females was abdominal subcutaneous fat by computed tomography significantly greater in NWIR than NWIS. In NWIR males high-density lipoprotein-cholesterol and fat free mass were significantly less, and fasting insulin was greater than NWIS males. For the entire NWIS population, Kaplan-Meier disease-free survival analysis showed longer times free of hypertension, hyperglycemia, and some cardiovascular diseases than for NWIR. Conclusions: There are sex-specific phenotypes of NWIR in Caucasian adults. NWIR may be associated with accelerated onset of some adverse medical outcomes.

6.
Diabetes ; 73(1): 23-37, 2024 Jan 01.
Article in English | MEDLINE | ID: mdl-37862464

ABSTRACT

We investigated the link between enhancement of SI (by hyperinsulinemic-euglycemic clamp) and muscle metabolites after 12 weeks of aerobic (high-intensity interval training [HIIT]), resistance training (RT), or combined training (CT) exercise in 52 lean healthy individuals. Muscle RNA sequencing revealed a significant association between SI after both HIIT and RT and the branched-chain amino acid (BCAA) metabolic pathway. Concurrently with increased expression and activity of branched-chain ketoacid dehydrogenase enzyme, many muscle amino metabolites, including BCAAs, glutamate, phenylalanine, aspartate, asparagine, methionine, and γ-aminobutyric acid, increased with HIIT, supporting the substantial impact of HIIT on amino acid metabolism. Short-chain C3 and C5 acylcarnitines were reduced in muscle with all three training modes, but unlike RT, both HIIT and CT increased tricarboxylic acid metabolites and cardiolipins, supporting greater mitochondrial activity with aerobic training. Conversely, RT and CT increased more plasma membrane phospholipids than HIIT, suggesting a resistance exercise effect on cellular membrane protection against environmental damage. Sex and age contributed modestly to the exercise-induced changes in metabolites and their association with cardiometabolic parameters. Integrated transcriptomic and metabolomic analyses suggest various clusters of genes and metabolites are involved in distinct effects of HIIT, RT, and CT. These distinct metabolic signatures of different exercise modes independently link each type of exercise training to improved SI and cardiometabolic risk. ARTICLE HIGHLIGHTS: We aimed to understand the link between skeletal muscle metabolites and cardiometabolic health after exercise training. Although aerobic, resistance, and combined exercise training each enhance muscle insulin sensitivity as well as other cardiometabolic parameters, they disparately alter amino and citric acid metabolites as well as the lipidome, linking these metabolomic changes independently to the improvement of cardiometabolic risks with each exercise training mode. These findings reveal an important layer of the unique exercise mode-dependent changes in muscle metabolism, which may eventually lead to more informed exercise prescription for improving SI.


Subject(s)
Cardiovascular Diseases , High-Intensity Interval Training , Humans , Cardiometabolic Risk Factors , Exercise/physiology , Muscle, Skeletal/metabolism , Exercise Therapy , Cardiovascular Diseases/metabolism
7.
Cell Metab ; 35(11): 1996-2010.e6, 2023 11 07.
Article in English | MEDLINE | ID: mdl-37939659

ABSTRACT

Substantial divergence in cardio-metabolic risk, muscle size, and performance exists between men and women. Considering the pivotal role of skeletal muscle in human physiology, we investigated and found, based on RNA sequencing (RNA-seq), that differences in the muscle transcriptome between men and women are largely related to testosterone and estradiol and much less related to genes located on the Y chromosome. We demonstrate inherent unique, sex-dependent differences in muscle transcriptional responses to aerobic, resistance, and combined exercise training in young and older cohorts. The hormonal changes with age likely explain age-related differential expression of transcripts. Furthermore, in primary human myotubes we demonstrate the profound but distinct effects of testosterone and estradiol on amino acid incorporation to multiple individual proteins with specific functions. These results clearly highlight the potential of designing exercise programs tailored specifically to men and women and have implications for people who change gender by altering their hormone profile.


Subject(s)
Muscle Fibers, Skeletal , Muscle, Skeletal , Male , Humans , Female , Muscle, Skeletal/metabolism , Muscle Fibers, Skeletal/metabolism , Exercise/physiology , Testosterone/metabolism , Testosterone/pharmacology , Estradiol/pharmacology
8.
JCI Insight ; 8(22)2023 Nov 22.
Article in English | MEDLINE | ID: mdl-37815864

ABSTRACT

Aging and many illnesses and injuries impair skeletal muscle mass and function, but the molecular mechanisms are not well understood. To better understand the mechanisms, we generated and studied transgenic mice with skeletal muscle-specific expression of growth arrest and DNA damage inducible α (GADD45A), a signaling protein whose expression in skeletal muscle rises during aging and a wide range of illnesses and injuries. We found that GADD45A induced several cellular changes that are characteristic of skeletal muscle atrophy, including a reduction in skeletal muscle mitochondria and oxidative capacity, selective atrophy of glycolytic muscle fibers, and paradoxical expression of oxidative myosin heavy chains despite mitochondrial loss. These cellular changes were at least partly mediated by MAP kinase kinase kinase 4, a protein kinase that is directly activated by GADD45A. By inducing these changes, GADD45A decreased the mass of muscles that are enriched in glycolytic fibers, and it impaired strength, specific force, and endurance exercise capacity. Furthermore, as predicted by data from mouse models, we found that GADD45A expression in skeletal muscle was associated with muscle weakness in humans. Collectively, these findings identify GADD45A as a mediator of mitochondrial loss, atrophy, and weakness in mouse skeletal muscle and a potential target for muscle weakness in humans.


Subject(s)
Mitochondria, Muscle , Muscle, Skeletal , Muscular Atrophy , Animals , Humans , Mice , Aging , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Mitochondria, Muscle/metabolism , Muscle Weakness/metabolism , Muscle, Skeletal/metabolism , Muscular Atrophy/pathology
9.
J Appl Physiol (1985) ; 135(4): 763-774, 2023 10 01.
Article in English | MEDLINE | ID: mdl-37616334

ABSTRACT

This study investigated how different exercise training modalities influence skeletal muscle mitochondrial dynamics. Healthy [average body mass index (BMI): 25.8 kg/m2], sedentary younger and older participants underwent 12 wk of supervised high-intensity aerobic interval training (HIIT; n = 13), resistance training (RT; n = 14), or combined training (CT; n = 11). Mitochondrial structure was assessed using transmission electron microscopy (TEM). Regulators of mitochondrial fission and fusion, cardiorespiratory fitness (V̇o2peak), insulin sensitivity via a hyperinsulinemic-euglycemic clamp, and muscle mitochondrial respiration were assessed. TEM showed increased mitochondrial volume, number, and perimeter following HIIT (P < 0.01), increased mitochondrial number following CT (P < 0.05), and no change in mitochondrial abundance after RT. Increased mitochondrial volume associated with increased mitochondrial respiration and insulin sensitivity following HIIT (P < 0.05). Increased mitochondrial perimeter associated with increased mitochondrial respiration, insulin sensitivity, and V̇o2peak following HIIT (P < 0.05). No such relationships were observed following CT or RT. OPA1, a regulator of fusion, was increased following HIIT (P < 0.05), whereas FIS1, a regulator of fission, was decreased following HIIT and CT (P < 0.05). HIIT also increased the ratio of OPA1/FIS1 (P < 0.01), indicative of the balance between fission and fusion, which positively correlated with improvements in respiration, insulin sensitivity, and V̇o2peak (P < 0.05). In conclusion, HIIT induces a larger, more fused mitochondrial tubular network. Changes indicative of increased fusion following HIIT associate with improvements in mitochondrial respiration, insulin sensitivity, and V̇o2peak supporting the idea that enhanced mitochondrial fusion accompanies notable health benefits of HIIT.NEW & NOTEWORTHY We assessed the effects of 12 wk of supervised high-intensity interval training (HIIT), resistance training, and combined training (CT) on skeletal muscle mitochondrial abundance and markers of fission and fusion. HIIT increased mitochondrial area and size and promoted protein changes indicative of increased mitochondrial fusion, whereas lessor effects were observed after CT and no changes were observed after RT. Furthermore, increased mitochondrial area and size after HIIT associated with improved mitochondrial respiration, cardiorespiratory fitness, and insulin sensitivity.


Subject(s)
Cardiovascular Diseases , Insulin Resistance , Humans , Mitochondrial Dynamics , Muscle, Skeletal , Exercise
10.
Physiol Genomics ; 55(8): 338-344, 2023 08 01.
Article in English | MEDLINE | ID: mdl-37335021

ABSTRACT

Maximal aerobic exercise capacity [maximal oxygen consumption (V̇o2max)] is one of the strongest predictors of morbidity and mortality. Aerobic exercise training can increase V̇o2max, but inter-individual variability is marked and unexplained physiologically. The mechanisms underlying this variability have major clinical implications for extending human healthspan. Here, we report a novel transcriptome signature related to ΔV̇o2max with exercise training detected in whole blood RNA. We used RNA-Seq to characterize transcriptomic signatures of ΔV̇o2max in healthy women who completed a 16-wk randomized controlled trial comparing supervised, higher versus lower aerobic exercise training volume and intensity (4 training groups, fully crossed). We found significant baseline gene expression differences in subjects who responded to aerobic exercise training with robust versus little/no ΔV̇o2max, and differentially expressed genes/transcripts were mostly related to inflammatory signaling and mitochondrial function/protein translation. Baseline gene expression signatures associated with robust versus little/no ΔV̇o2max were also modulated by exercise training in a dose-dependent manner, and they predicted ΔV̇o2max in this and a separate dataset. Collectively, our data demonstrate the potential utility of using whole blood transcriptomics to study the biology of inter-individual variability in responsiveness to the same exercise training stimulus.


Subject(s)
Endurance Training , Transcriptome , Humans , Female , Transcriptome/genetics , Exercise/physiology , Exercise Tolerance , Oxygen Consumption/genetics
11.
Front Genet ; 14: 1113058, 2023.
Article in English | MEDLINE | ID: mdl-37351342

ABSTRACT

Introduction: Long axial length (AL) is a risk factor for myopia. Although family studies indicate that AL has an important genetic component with heritability estimates up to 0.94, there have been few reports of AL-associated loci. Methods: Here, we conducted a multiethnic genome-wide association study (GWAS) of AL in 19,420 adults of European, Latino, Asian, and African ancestry from the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort, with replication in a subset of the Consortium for Refractive Error and Myopia (CREAM) cohorts of European or Asian ancestry. We further examined the effect of the identified loci on the mean spherical equivalent (MSE) within the GERA cohort. We also performed genome-wide genetic correlation analyses to quantify the genetic overlap between AL and MSE or myopia risk in the GERA European ancestry sample. Results: Our multiethnic GWA analysis of AL identified a total of 16 genomic loci, of which 5 are novel. We found that all AL-associated loci were significantly associated with MSE after Bonferroni correction. We also found that AL was genetically correlated with MSE (rg = -0.83; SE, 0.04; p = 1.95 × 10-89) and myopia (rg = 0.80; SE, 0.05; p = 2.84 × 10-55). Finally, we estimated the array heritability for AL in the GERA European ancestry sample using LD score regression, and found an overall heritability estimate of 0.37 (s.e. = 0.04). Discussion: In this large and multiethnic study, we identified novel loci, associated with AL at a genome-wide significance level, increasing substantially our understanding of the etiology of AL variation. Our results also demonstrate an association between AL-associated loci and MSE and a shared genetic basis between AL and myopia risk.

12.
Philos Trans A Math Phys Eng Sci ; 381(2246): 20220136, 2023 May.
Article in English | MEDLINE | ID: mdl-36907217

ABSTRACT

Taylor-Couette flow is a canonical flow to study Taylor-Görtler (TG) instability or centrifugal instability and the associated vortices. TG instability has been traditionally associated with flow over curved surfaces or geometries. In the computational study, we confirm the presence of TG-like near-wall vortical structures in two lid-driven flow systems, the Vogel-Escudier (VE) and the lid-driven cavity (LDC) flows. The VE flow is generated inside a circular cylinder by a rotating lid (top lid in the present study), while the LDC flow is generated inside a square or rectangular cavity by the linear movement of the lid. We look at the emergence of these vortical structures through reconstructed phase space diagrams and find that the TG-like vortices are seen in the chaotic regimes in both flows. In the VE flow, these vortices are seen when the side-wall boundary layer instability sets in at large [Formula: see text]. The VE flow is observed to go to a chaotic state in a sequence of events from a steady state at low [Formula: see text]. In contrast to VE flows, in the LDC flow with no curved boundaries, TG-like vortices are seen at the emergence of unsteadiness when the flow exhibits a limit cycle. The LDC flow is observed to have transitioned to chaos from the steady state through a periodic oscillatory state. Various aspect ratio cavities are examined in both flows for the presence of TG-like vortices. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical transactions paper (Part 2)'.

13.
Indian Pediatr ; 60(3): 202-206, 2023 03 15.
Article in English | MEDLINE | ID: mdl-36604939

ABSTRACT

OBJECTIVE: To evaluate the prevalence of vitamin D deficiency (VDD) and its correlates among apparently healthy children and adolescents. METHODS: We carried out a secondary analysis of data of Comprehensive National Nutrition Survey 2016-18 to analyze the pre-valence and predictors of VDD among Indian children and adolescents. RESULTS: The over-all prevalence of VDD in preschool children (1-4 years), school age (5-9 years) children, and adolescents (10-19 years) was 13.7%, 18.2%, and 23.9%, respectively. Age, living in urban area, and winter season were significantly associated with VDD. Vegetarian diet and high-income households were the main risk factors observed in 5-19 years age category. Female sex and less than three hour of physical activity/week were independent risk factors among adolescents. CONCLUSION: The prevalence and determinants of VDD across different age-groups are reported, and these should be interpreted and addressed to decrease the burden of VDD in India.


Subject(s)
Vitamin D Deficiency , Vitamin D , Child, Preschool , Humans , Female , Adolescent , Child , Prevalence , Vitamin D Deficiency/epidemiology , Nutritional Status , India/epidemiology
14.
Appl Radiat Isot ; 191: 110565, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36423501

ABSTRACT

We report the development of a manual module for the preparation of [18F]NaF for metastatic bone cancer imaging. By using this simple module, [18F]NaF production can be carried out inexpensively without using commercially available kits. The module can be used for making [18F]NaF from freshly irradiated H218O water or with left over activity in the target after [18F]FDG production. The product meets all quality control parameters.


Subject(s)
Positron Emission Tomography Computed Tomography , Sodium Fluoride , Cost-Benefit Analysis , Diagnostic Imaging , Fluorodeoxyglucose F18
15.
Nat Aging ; 2(7): 601-615, 2022 07.
Article in English | MEDLINE | ID: mdl-36147777

ABSTRACT

Senescence is a cell fate that contributes to multiple aging-related pathologies. Despite profound age-associated changes in skeletal muscle (SkM), whether its constituent cells are prone to senesce has not been methodically examined. Herein, using single cell and bulk RNA-sequencing and complementary imaging methods on SkM of young and old mice, we demonstrate that a subpopulation of old fibroadipogenic progenitors highly expresses p16 Ink4a together with multiple senescence-related genes and, concomitantly, exhibits DNA damage and chromatin reorganization. Through analysis of isolated myofibers, we also detail a senescence phenotype within a subset of old cells, governed instead by p2 Cip1 . Administration of a senotherapeutic intervention to old mice countered age-related molecular and morphological changes and improved SkM strength. Finally, we found that the senescence phenotype is conserved in SkM from older humans. Collectively, our data provide compelling evidence for cellular senescence as a hallmark and potentially tractable mediator of SkM aging.


Subject(s)
Aging , Cellular Senescence , Humans , Mice , Animals , Aging/genetics , Cellular Senescence/genetics , Cyclin-Dependent Kinase Inhibitor p16/genetics , Phenotype , Muscle, Skeletal
16.
Diabetes ; 71(8): 1636-1648, 2022 08 01.
Article in English | MEDLINE | ID: mdl-35621914

ABSTRACT

Transient insulin deprivation with concurrent hyperglucagonemia is a catabolic state that can occur in type 1 diabetes. To evaluate glucagon's catabolic effect in the setting of its glucogenic effect, we measured the regional exchanges of amino acid metabolites (amino-metabolites) across muscle and splanchnic beds in 16 healthy humans during either somatostatin followed by glucagon or saline infusion alone. Despite a twofold or greater increase in the regional exchange of amino-metabolites by glucagon, whole-body kinetics and concentrations of amino acids (AA) remained stable. Glucagon increased the splanchnic uptake of not only gluconeogenic but also essential (EAA) AA while increasing their release from the muscle bed. Regional tracer-based kinetics and 3-methylhistidine release indicate that EAA release from muscle is likely caused by reduced protein synthesis rather than increased protein degradation. Furthermore, many metabolites known to affect insulin action and metabolism were altered by hyperglucagonemia including increase in branched-chain AA and keto acids of leucine and isoleucine in arterial plasma. Further, an increase in arterial concentrations of α-aminoadipic acid arising from increased conversion from lysine in the splanchnic bed was noted. These results demonstrate that hyperglucagonemia during hypoinsulinemia increases net muscle protein catabolism and substantially increases the exchange of amino metabolites across splanchnic and muscle beds.


Subject(s)
Glucagon , Insulin , Amino Acids/metabolism , Glucagon/metabolism , Humans , Insulin/metabolism , Insulin, Regular, Human , Muscle, Skeletal/metabolism , Proteolysis
17.
Nat Commun ; 13(1): 2324, 2022 04 28.
Article in English | MEDLINE | ID: mdl-35484130

ABSTRACT

Resistance exercise training (RET) is an effective countermeasure to sarcopenia, related frailty and metabolic disorders. Here, we show that an RET-induced increase in PGC-1α4 (an isoform of the transcriptional co-activator PGC-1α) expression not only promotes muscle hypertrophy but also enhances glycolysis, providing a rapid supply of ATP for muscle contractions. In human skeletal muscle, PGC-1α4 binds to the nuclear receptor PPARß following RET, resulting in downstream effects on the expressions of key glycolytic genes. In myotubes, we show that PGC-1α4 overexpression increases anaerobic glycolysis in a PPARß-dependent manner and promotes muscle glucose uptake and fat oxidation. In contrast, we found that an acute resistance exercise bout activates glycolysis in an AMPK-dependent manner. These results provide a mechanistic link between RET and improved glucose metabolism, offering an important therapeutic target to counteract aging and inactivity-induced metabolic diseases benefitting those who cannot exercise due to many reasons.


Subject(s)
PPAR-beta , Resistance Training , Anaerobiosis , Glycolysis , Humans , PPAR-beta/metabolism , Transcription Factors/metabolism
18.
J Clin Endocrinol Metab ; 107(2): 346-362, 2022 01 18.
Article in English | MEDLINE | ID: mdl-34614176

ABSTRACT

CONTEXT: Familial partial lipodystrophy (FPL), Dunnigan variety is characterized by skeletal muscle hypertrophy and insulin resistance besides fat loss from the extremities. The cause for the muscle hypertrophy and its functional consequences is not known. OBJECTIVE: To compare muscle strength and endurance, besides muscle protein synthesis rate between subjects with FPL and matched controls (n = 6 in each group). In addition, we studied skeletal muscle mitochondrial function and gene expression pattern to help understand the mechanisms for the observed differences. METHODS: Body composition by dual-energy X-ray absorptiometry, insulin sensitivity by minimal modelling, assessment of peak muscle strength and fatigue, skeletal muscle biopsy and calculation of muscle protein synthesis rate, mitochondrial respirometry, skeletal muscle transcriptome, proteome, and gene set enrichment analysis. RESULTS: Despite increased muscularity, FPL subjects did not demonstrate increased muscle strength but had earlier fatigue on chest press exercise. Decreased mitochondrial state 3 respiration in the presence of fatty acid substrate was noted, concurrent to elevated muscle lactate and decreased long-chain acylcarnitine. Based on gene transcriptome, there was significant downregulation of many critical metabolic pathways involved in mitochondrial biogenesis and function. Moreover, the overall pattern of gene expression was indicative of accelerated aging in FPL subjects. A lower muscle protein synthesis and downregulation of gene transcripts involved in muscle protein catabolism was observed. CONCLUSION: Increased muscularity in FPL is not due to increased muscle protein synthesis and is likely due to reduced muscle protein degradation. Impaired mitochondrial function and altered gene expression likely explain the metabolic abnormalities and skeletal muscle dysfunction in FPL subjects.


Subject(s)
Lipodystrophy, Familial Partial/physiopathology , Mitochondria, Muscle/pathology , Muscle, Skeletal/physiopathology , Absorptiometry, Photon , Adult , Aged , Female , Gene Expression Profiling , Humans , Lipodystrophy, Familial Partial/genetics , Lipodystrophy, Familial Partial/metabolism , Lipodystrophy, Familial Partial/pathology , Male , Middle Aged , Mitochondria, Muscle/metabolism , Muscle Strength/physiology , Muscle, Skeletal/cytology , Muscle, Skeletal/pathology , Physical Endurance/physiology , Proteolysis , Young Adult
19.
Indian J Med Res ; 154(3): 423-432, 2021 Mar.
Article in English | MEDLINE | ID: mdl-34854426

ABSTRACT

Adopting sun exposure as a low-cost sustainable strategy in tropical countries needs critical analysis for its feasibility and inclusion in national policy. This review explores the opportunities and challenges associated with sun exposure in tropical countries and discusses potential strategies that may be adopted for promoting sun exposure. For this, two strands of evidence were reviewed; trials on sun exposure, analysed for risk of bias and, the environmental factors that influence acquisition of vitamin D from sun exposure in the context of on-going ecological and nutritional transition. Compilation of data from available databases in terms of deficiency, per cent rural population, status of fortification, air pollution, ultraviolet index, skin reflectance and skin cancer prevalence were done. In the context of environmental and lifestyle-related challenges, opportunities go hand-in-hand in terms of built environment, variability in air pollution and personal factors such as skin pigmentation, precursor availability and general nutritional status. Contextual policy decisions should consider urban and rural development planning, control of air pollution, targeted guidelines for indigenous and immigrant population and use of space technology in educating general population for balanced sun exposure as essential components for a sustainable strategy. Important opportunities exist for tropical countries to develop sun exposure as a strategy for acquiring vitamin D and these need to be explored.


Subject(s)
Sunlight , Vitamin D Deficiency , Developing Countries , Humans , Life Style , Sunlight/adverse effects , Vitamin D/therapeutic use , Vitamin D Deficiency/epidemiology , Vitamin D Deficiency/prevention & control
20.
Front Cell Dev Biol ; 9: 735001, 2021.
Article in English | MEDLINE | ID: mdl-34805145

ABSTRACT

Extracellular vesicles (EVs) are emerging mediators of intercellular communication in nonalcoholic steatohepatitis (NASH). Palmitate, a lipotoxic saturated fatty acid, activates hepatocellular endoplasmic reticulum stress, which has been demonstrated to be important in NASH pathogenesis, including in the release of EVs. We have previously demonstrated that the release of palmitate-stimulated EVs is dependent on the de novo synthesis of ceramide, which is trafficked by the ceramide transport protein, STARD11. The trafficking of ceramide is a critical step in the release of lipotoxic EVs, as cells deficient in STARD11 do not release palmitate-stimulated EVs. Here, we examined the hypothesis that protein cargoes are trafficked to lipotoxic EVs in a ceramide-dependent manner. We performed quantitative proteomic analysis of palmitate-stimulated EVs in control and STARD11 knockout hepatocyte cell lines. Proteomics was performed on EVs isolated by size exclusion chromatography, ultracentrifugation, and density gradient separation, and EV proteins were measured by mass spectrometry. We also performed human EV proteomics from a control and a NASH plasma sample, for comparative analyses with hepatocyte-derived lipotoxic EVs. Size exclusion chromatography yielded most unique EV proteins. Ceramide-dependent lipotoxic EVs contain damage-associated molecular patterns and adhesion molecules. Haptoglobin, vascular non-inflammatory molecule-1, and insulin-like growth factor-binding protein complex acid labile subunit were commonly detected in NASH and hepatocyte-derived ceramide-dependent EVs. Lipotoxic EV proteomics provides novel candidate proteins to investigate in NASH pathogenesis and as diagnostic biomarkers for hepatocyte-derived EVs in NASH patients.

SELECTION OF CITATIONS
SEARCH DETAIL
...