bims-mifefi 2024-05-26 papers

Issue of 2024–05–26
five papers selected by
Kayla Vandiver, East Carolina University

J Appl Physiol (1985). 2024 May 23.

Sexual Dimorphisms in Skeletal Muscle: Current Concepts and Research Horizons.

Marianne E Emmert, Andrew S Emmert, Qingnian Goh, Roger Cornwall.

The complex compositional and functional nature of skeletal muscle makes this organ an essential topic of study for biomedical researchers and clinicians. An additional layer of complexity is added with the consideration of sex as a biological variable. Recent research advances have revealed sexual dimorphisms in developmental biology, muscle homeostasis, adaptive responses, and disorders relating to skeletal muscle. Many of the observed sex differences have hormonal and molecular mechanistic underpinnings, while others have yet to be elucidated. Future research is needed to investigate the mechanisms dictating sex-based differences in the various aspects of skeletal muscle. As such, it is necessary that skeletal muscle biologists ensure that both female and male subjects are represented in biomedical and clinical studies to facilitate the successful testing and development of therapeutics for all patients.

Keywords: Muscle adaptation; Muscle disease; Muscle growth; Sexual dimorphisms; Skeletal muscle

DOI: https://doi.org/10.1152/japplphysiol.00529.2023

Nutrients. 2024 May 13. pii: 1467. [Epub ahead of print]16(10):

Gender Differences in the Impact of a High-Fat, High-Sugar Diet in Skeletal Muscles of Young Female and Male Mice.

Luana Toniolo, Silvia Gazzin, Natalia Rosso, Pablo Giraudi, Deborah Bonazza, Monica Concato, Fabrizio Zanconati, Claudio Tiribelli, Emiliana Giacomello.

In the context of the increasing number of obese individuals, a major problem is represented by obesity and malnutrition in children. This condition is mainly ascribable to unbalanced diets characterized by high intakes of fat and sugar. Childhood obesity and malnutrition are not only associated with concurrent pathologies but potentially compromise adult life. Considering the strict correlation among systemic metabolism, obesity, and skeletal muscle health, we wanted to study the impact of juvenile malnutrition on the adult skeletal muscle. To this aim, 3-week-old C56BL/6 female and male mice were fed for 20 weeks on a high-fat. high-sugar diet, and their muscles were subjected to a histological evaluation. MyHCs expression, glycogen content, intramyocellular lipids, mitochondrial activity, and capillary density were analyzed on serial sections to obtain the metabolic profile. Our observations indicate that a high-fat, high-sugar diet alters the metabolic profile of skeletal muscles in a sex-dependent way and induces the increase in type II fibers, mitochondrial activity, and lipid content in males, while reducing the capillary density in females. These data highlight the sex-dependent response to nutrition, calling for the development of specific strategies and for a systematic inclusion of female subjects in basic and applied research in this field.

Keywords: Western diet; cell metabolism; fiber plasticity; obesity; skeletal muscle

DOI: https://doi.org/10.3390/nu16101467

Int J Mol Sci. 2024 May 07. pii: 5066. [Epub ahead of print]25(10):

Strength Training Protects High-Fat-Fed Ovariectomized Mice against Insulin Resistance and Hepatic Steatosis.

Jessica D M Santos, José F T Silva, Ester Dos S Alves, Alessandra G Cruz, Anne R M Santos, Felipe N Camargo, Carlos H Z Talarico, Carlos A A Silva, João Paulo Camporez.

Menopause is characterized by a reduction in sex hormones in women and is associated with metabolic changes, including fatty liver and insulin resistance. Lifestyle changes, including a balanced diet and physical exercise, are necessary to prevent these undesirable changes. Strength training (ST) has been widely used because of the muscle and metabolic benefits it provides. Our study aims to evaluate the effects of ST on hepatic steatosis and insulin resistance in ovariectomized mice fed a high-fat diet (HFD) divided into four groups as follows: simulated sedentary surgery (SHAM-SED), trained simulated surgery (SHAM-EXE), sedentary ovariectomy (OVX-SED), and trained ovariectomy (OVX-EXE). They were fed an HFD for 9 weeks. ST was performed thrice a week. ST efficiently reduced body weight and fat percentage and increased lean mass in OVX mice. Furthermore, ST reduced the accumulation of ectopic hepatic lipids, increased AMPK phosphorylation, and inhibited the de novo lipogenesis pathway. OVX-EXE mice also showed a better glycemic profile, associated with greater insulin sensitivity identified by the euglycemic-hyperinsulinemic clamp, and reduced markers of hepatic oxidative stress compared with sedentary animals. Our data support the idea that ST can be indicated as a non-pharmacological treatment approach to mitigate metabolic changes resulting from menopause.

Keywords: insulin resistance; menopause; non-alcoholic fatty liver disease

DOI: https://doi.org/10.3390/ijms25105066

Nutrients. 2024 May 12. pii: 1457. [Epub ahead of print]16(10):

The Role of Nutrition and Body Composition on Metabolism.

Yuyang Wang, Botian Chen, Defu Ma.

Metabolism encompasses the entire array of chemical reactions continuously occurring within the body that sustain life and maintain normal physiological functions [...].

DOI: https://doi.org/10.3390/nu16101457

J Cell Physiol. 2024 May 22.

Kit Neikirk, Kinuthia Kabugi, Margaret Mungai, Bartosz Kula, Nathan Smith, Antentor O Hinton.

Mitochondrial dysfunction has long been implicated in the development of insulin resistance, which is a hallmark of type 2 diabetes. However, recent studies reveal ethnicity-related differences in mitochondrial processes, underscoring the need for nuance in studying mitochondrial dysfunction and insulin sensitivity. Furthermore, the higher prevalence of type 2 diabetes among African Americans and individuals of African descent has brought attention to the role of ethnicity in disease susceptibility. In this review, which covers existing literature, genetic studies, and clinical data, we aim to elucidate the complex relationship between mitochondrial alterations and insulin stimulation by considering how mitochondrial dynamics, contact sites, pathways, and metabolomics may be differentially regulated across ethnicities, through mechanisms such as single nucleotide polymorphisms (SNPs). In addition to achieving a better understanding of insulin stimulation, future studies identifying novel regulators of mitochondrial structure and function could provide valuable insights into ethnicity-dependent insulin signaling and personalized care.

Keywords: diabetes; health disparities; individualized care; insulin; mitochondria

DOI: https://doi.org/10.1002/jcp.31317