Hypercaloric low-carbohydrate high-fat diet protects against the development of nonalcoholic fatty liver disease in obese mice in contrast to isocaloric Western diet.

Objective: Obesity and metabolic complications, such as type 2 diabetes and nonalcoholic fatty liver disease (NAFLD), are one of the greatest public health challenges of the 21st century. The major role of high sugar and carbohydrate consumption rather than caloric intake in obesity and NAFLD pathophysiology remains a subject of debate. A low-carbohydrate but high-fat diet (LCHFD) has shown promising results in obesity management, but its effects in preventing NAFLD need to be detailed. This study aims to compare the effects of a LCHFD with a high-fat high-sugar obesogenic Western diet (WD) on the progression of obesity, type 2 diabetes, and nonalcoholic fatty liver disease. Methods: Male C57BL/6J mice were initially fed a WD for 10 weeks. Subsequently, they were either switched to a LCHFD or maintained on the WD for an additional 6 weeks. Hepatic effects of the diet were explored by histological staining and RT-qPCR. Results: After the initial 10 weeks WD feeding, LCHF diet demonstrated effectiveness in halting weight gain, maintaining a normal glucose tolerance and insulin levels, in comparison to the WD-fed mice, which developed obesity, glucose intolerance, increased insulin levels and induced NAFLD. In the liver, LCHFD mitigated the accumulation of hepatic triglycerides and the increase in Fasn relative gene expression compared to the WD mice. Beneficial effects of the LCHFD occurred despite a similar calorie intake compared to the WD mice. Conclusion: Our results emphasize the negative impact of a high sugar/carbohydrate and lipid association for obesity progression and NAFLD development. LCHFD has shown beneficial effects for NAFLD management, notably improving weight management, and maintaining a normal glucose tolerance and liver health.

Changes in Macronutrients during Dieting Lead to Weight Cycling and Metabolic Complications in Mouse Model.

Weight cycling is a major challenge in obesity management. Caloric restriction is known to promote this phenomenon, but the impact of macronutrient changes during dieting remains unclear. This study aimed to determine the role of macronutrient changes in weight maintenance without caloric restriction by alternating between two hypercaloric diets: a high-carbohydrate, high-fat Western diet (WD) and a low-carbohydrate, high-fat diet (LCHDF). Obesity was induced in 8-week-old C57BL/6 male mice by 10 weeks of WD feeding. Then, the mice were subjected to 12 weeks of LCHFD interspersed with WD (I-WD), 3 periods of 2-week LCHFD followed by 2 periods of 3-week WD, or 12 weeks of continuous WD (C-WD). C-WD and I-WD mice were compared to standard diet (SD) mice. In the I-WD group, each LCHFD period decreased weight gain, but mice regained weight after WD resumption. I-WD mice exhibited obesity, dyslipidemia, and glucose intolerance, similarly to the C-WD mice. I-WD mice also developed nonalcoholic steatohepatitis, associated with an increase in type-III collagen gene expression and a decrease in FGF21 protein levels, in comparison with SD. I-WD mice developed weight cycling despite maintaining a high caloric consumption, suggesting that changes in macronutrients during dieting are also a trigger of weight regain.

A single chemotherapy administration induces muscle atrophy, mitochondrial alterations and apoptosis in breast cancer patients.

BACKGROUND: Breast cancer patients are commonly treated with sequential administrations of epirubicin-cyclophosphamide (EC) and paclitaxel (TAX). The chronic effect of this treatment induces skeletal muscle alterations, but the specific effect of each chemotherapy agent is unknown. This study aimed to investigate the effect of EC or TAX administration on skeletal muscle homeostasis in breast cancer patients. METHODS: Twenty early breast cancer patients undergoing EC followed by TAX chemotherapies were included. Two groups of 10 women were established and performed vastus lateralis skeletal muscle biopsies either before the first administration (pre) of EC (50 ± 14 years) or TAX (50 ± 16 years) and 4 days later (post). Mitochondrial respiratory capacity recording, reactive oxygen species production, western blotting and histological analyses were performed. RESULTS: Decrease in muscle fibres cross-sectional area was only observed post-EC (-25%; P < 0.001), associated with a reduction in mitochondrial respiratory capacity for the complex I (CI)-linked substrate state (-32%; P = 0.001), oxidative phosphorylation (OXPHOS) by CI (-35%; P = 0.002), CI&CII (-26%; P = 0.022) and CII (-24%; P = 0.027). If H2 O2 production was unchanged post-EC, an increase was observed post-TAX for OXPHOS by CII (+25%; P = 0.022). We found a decrease in makers of mitochondrial content, as shown post-EC by a decrease in the protein levels of citrate synthase (-53%; P < 0.001) and VDAC (-39%; P < 0.001). Despite no changes in markers of mitochondrial fission, a decrease in the expression of a marker of mitochondrial inner-membrane fusion was found post-EC (OPA1; -60%; P < 0.001). We explored markers of mitophagy and found reductions post-EC in the protein levels of PINK1 (-63%; P < 0.001) and Parkin (-56%; P = 0.005), without changes post-TAX. An increasing trend in Bax protein level was found post-EC (+96%; P = 0.068) and post-TAX (+77%; P = 0.073), while the Bcl-2 level was decreased only post-EC (-52%; P = 0.007). If an increasing trend in TUNEL-positive signal was observed post-EC (+68%; P = 0.082), upregulation was highlighted post-TAX (+86%; P < 0.001), suggesting activation of the apoptosis process. CONCLUSIONS: We demonstrated that a single administration of EC induced, in only 4 days, skeletal muscle atrophy and mitochondrial alterations in breast cancer patients. These alterations were characterized by reductions in mitochondrial function and content as well as impairment of mitochondrial dynamics and an increase in apoptosis. TAX administration did not worsen these alterations as this group had already received EC during the preceding weeks. However, it resulted in an increased apoptosis, likely in response to the increased H2 O2 production.

Autologous mitochondrial transplantation in male mice as a strategy to prevent deleterious effects of peripheral ischemia-reperfusion.

Ischemia-reperfusion (IR) is known to induce severe tissue damage, notably through mitochondrial dysfunction. Mitochondrial transplantation has emerged as a promising therapeutic strategy in cardiac IR; however, few studies have previously assessed its efficacy in the context of peripheral IR. Therefore, the objective of this study was to assess the effect of mitochondrial transplantation in a hindlimb model of IR injury. Thirty-six SWISS mice were divided into three groups: control (CTL, n = 12), ischemia-reperfusion (IR, n = 12), and IR with mitochondrial transplantation (MT, n = 12). Ischemia (2 h) was induced using the tourniquet model around the right hind limb in the IR and MT groups. In MT group, mitochondria isolated from the right rectus muscle, a nonischemic region, were injected shortly before reperfusion. Mitochondrial respiration, calcium retention capacity, and Western blotting analysis were performed 2 h after reperfusion. Compared with the CTL group, IR led to a decrease in the mitochondrial respiratory capacity, particularly for the basal state (-30%; P = 0.015), oxidative phosphorylation (-36%; P = 0.024), and calcium retention capacity (-45%; P = 0.007). Interestingly, mitochondrial transplantation partially restored these functions since no differences between MT and CTL groups were found. In addition, the administration of healthy mitochondria resulted in a positive regulation of redox balance and mitochondrial dynamics within the skeletal muscle. Although further investigations are needed to better characterize underlying mechanisms, mitochondrial transplantation represents a promising strategy in the setting of IR-induced muscular damage.NEW & NOTEWORTHY Ischemia-reperfusion injury leads to severe muscular damage. Even if prompt revascularization is the treatment of choice, muscular alterations can lead to severe sequalae as mitochondrial dysfunction. Accordingly, adjunctive strategies are needed to overcome the muscular damage. Mitochondrial transplantation has shown beneficial effects in cardiac ischemia-reperfusion, but its role in peripheral muscle is not well established. In this study, we found that mitochondrial transplantation partially restored muscular function when submitted to ischemia reperfusion.

Subcutaneous Administration of a Zwitterionic Chitosan-Based Hydrogel for Controlled Spatiotemporal Release of Monoclonal Antibodies.

Subcutaneous (SC) administration of monoclonal antibodies (mAbs) is a proven strategy for improving therapeutic outcomes and patient compliance. The current FDA-/EMA-approved enzymatic approach, utilizing recombinant human hyaluronidase (rHuPH20) to enhance mAbs SC delivery, involves degrading the extracellular matrix's hyaluronate to increase tissue permeability. However, this method lacks tunable release properties, requiring individual optimization for each mAb. Seeking alternatives, physical polysaccharide hydrogels emerge as promising candidates due to their tunable physicochemical and biodegradability features. Unfortunately, none have demonstrated simultaneous biocompatibility, biodegradability, and controlled release properties for large proteins (≥150 kDa) after SC delivery in clinical settings. Here, a novel two-component hydrogel comprising chitosan and chitosan@DOTAGA is introduced that can be seamlessly mixed with sterile mAbs formulations initially designed for intravenous (IV) administration, repurposing them as novel tunable SC formulations. Validated in mice and nonhuman primates (NHPs) with various mAbs, including trastuzumab and rituximab, the hydrogel exhibited biodegradability and biocompatibility features. Pharmacokinetic studies in both species demonstrated tunable controlled release, surpassing the capabilities of rHuPH20, with comparable parameters to the rHuPH20+mAbs formulation. These findings signify the potential for rapid translation to human applications, opening avenues for the clinical development of this novel SC biosimilar formulation.

Exacerbated central fatigue and reduced exercise capacity in early-stage breast cancer patients treated with chemotherapy.

PURPOSE: The present study aimed to characterize the etiology of exercise-induced neuromuscular fatigue and its consequences on the force-duration relationship to provide mechanistic insights into the reduced exercise capacity characterizing early-stage breast cancer patients. METHODS: Fifteen early-stage breast cancer patients and fifteen healthy women performed 60 maximal voluntary isometric quadriceps contractions (MVCs, 3 s of contraction, 2 s of relaxation). The critical force was determined as the mean force of the last six contractions, while W' was calculated as the force impulse generated above the critical force. Quadriceps muscle activation during exercise was estimated from vastus lateralis, vastus medialis and rectus femoris EMG. Central and peripheral fatigue were quantified via changes in pre- to postexercise quadriceps voluntary activation (ΔVA) and quadriceps twitch force (ΔQTw) evoked by supramaximal electrical stimulation, respectively. RESULTS: Early-stage breast cancer patients demonstrated lower MVC than controls preexercise (- 15%, P = 0.022), and this reduction persisted throughout the 60-MVC exercise (- 21%, P = 0.002). The absolute critical force was lower in patients than in controls (144 ± 29N vs. 201 ± 47N, respectively, P < 0.001), while W' was similar (P = 0.546), resulting in lower total work done (- 23%, P = 0.001). This was associated with lower muscle activation in the vastus lateralis (P < 0.001), vastus medialis (P = 0.003) and rectus femoris (P = 0.003) in patients. Immediately following exercise, ΔVA showed a greater reduction in patients compared to controls (- 21.6 ± 13.3% vs. - 12.6 ± 7.7%, P = 0.040), while ΔQTw was similar (- 60.2 ± 13.2% vs. - 52.8 ± 19.4%, P = 0.196). CONCLUSION: These findings support central fatigue as a primary cause of the reduction in exercise capacity characterizing early-stage breast cancer patients treated with chemotherapy. CLINICAL TRIALS REGISTRATION: No. NCT04639609-November 20, 2020.

Early skeletal muscle deconditioning and reduced exercise capacity during (neo)adjuvant chemotherapy in patients with breast cancer.

BACKGROUND: Fatigue is a hallmark of breast cancer and is associated with skeletal muscle deconditioning. If cancer-related fatigue occurs early during chemotherapy (CT), the development of skeletal muscle deconditioning and its effect on exercise capacity remain unclear. The aim of this study was to investigate the evolution of skeletal muscle deconditioning and exercise capacity in patients with early-stage breast cancer during CT. METHODS: Patients with breast cancer had a visit before undergoing CT, at 8 weeks, and at the end of chemotherapy (post-CT). Body composition was determined through bioelectrical impedance analysis. Knee extensor, handgrip muscle force and fatigue was quantified by performing maximal voluntary isometric contractions and exercise capacity using the 6-min walking test. Questionnaires were also administered to evaluate quality of life, cancer-related fatigue, and physical activity level. RESULTS: Among the 100 patients, reductions were found in muscle mass (-2.3%, p = .002), exercise capacity (-6.7%, p < .001), and knee extensor force (-4.9%, p < .001) post-CT, which occurred within the first 8 weeks of treatment with no further decrease thereafter. If muscle fatigue did not change, handgrip muscle force decreased post-CT only (-2.5%, p = .001), and exercise capacity continued to decrease between 8 weeks and post-CT (-4.6%, p < .001). Quality of life and cancer-related fatigue were impaired after 8 weeks (p < .001) and remained stable thereafter, whereas the physical activity level remained stable during chemotherapy. CONCLUSIONS: Similar to cancer-related fatigue, skeletal muscle deconditioning and reduced exercise capacity occurred early during breast cancer CT. Thus, it appears essential to prevent these alterations through exercise training implemented during CT.

Development of skeletal muscle atrophy and intermuscular adipose tissue in patients with early breast cancer treated with chemotherapy.

Chemotherapy is a common therapy to treat patients with breast cancer but also leads to skeletal muscle deconditioning. Skeletal muscle deconditioning is multifactorial and intermuscular adipose tissue (IMAT) accumulation is closely linked to muscle dysfunction. To date, there is no clinical study available investigating IMAT development through a longitudinal protocol and the underlying mechanisms remain unknown. Our study was dedicated to investigating IMAT content in patients with early breast cancer who were treated with chemotherapy and exploring the subsequent cellular mechanisms involved in its development. We included 13 women undergoing chemotherapy. Muscle biopsies and ultrasonography assessment were performed before and after chemotherapy completion. Histological and Western blotting analyses were conducted. We found a substantial increase in protein levels of three mature adipocyte markers (perilipin, +901%; adiponectin, +135%; FABP4, +321%; P < 0.05). These results were supported by an increase in oil red O-positive staining (+358%; P < 0.05). A substantial increase in PDGFRα protein levels was observed (+476%; P < 0.05) highlighting an increase in fibro-adipogenic progenitors (FAPs) content. The cross-sectional area of the vastus lateralis muscle fibers substantially decreased (-21%; P < 0.01), and muscle architecture was altered, as shown by a decrease in fascicle length (-15%; P < 0.05) and a decreasing trend in muscle thickness (-8%; P = 0.08). We demonstrated both IMAT development and muscle atrophy in patients with breast cancer who were treated with chemotherapy. FAPs, critical stem cells inducing both IMAT development and skeletal muscle atrophy, also increased, suggesting that FAPs likely play a critical role in the skeletal muscle deconditioning observed in patients with breast cancer who were treated with chemotherapy.

Exercise-Induced Fatigue in Hamstring versus Quadriceps Muscles and Consequences on the Torque-Duration Relationship in Men.

PURPOSE: The present study investigated the mechanisms of neuromuscular fatigue in quadriceps and hamstring muscles and its consequences on the torque-duration relationship. METHODS: Twelve healthy men performed a 5-min all-out exercise (3-s contraction, 2-s relaxation) with either quadriceps or hamstring muscles on separate days. Central fatigue and peripheral fatigue were quantified via changes in pre- to postexercise voluntary activation (VA) and potentiated twitch (P Tw ) torque evoked by supramaximal electrical stimulation, respectively. Critical torque was determined as the mean torque of the last six contractions, whereas W ' was calculated as the torque impulse done above critical torque. RESULTS: After exercise, maximal voluntary contraction (MVC) decreased to a greater magnitude ( P < 0.001) in quadriceps (-67% ± 9%) compared with hamstring (-51% ± 10%). ∆P Tw was also greater in quadriceps compared with hamstring (-69% ± 15% vs 55% ± 10%, P < 0.01), whereas central fatigue only developed in quadriceps (∆VA, -25% ± 28%). Hamstring demonstrated reduced critical torque compared with quadriceps (60 ± 12 vs 97 ± 26 N·m, P < 0.001) as well as drastically lower W ' (1001 ± 696 vs 8111 ± 2073 N·m·s, P < 0.001). No correlation was found between quadriceps and hamstring for any index of neuromuscular fatigue (∆MVC, ∆P Tw , or ∆VA). CONCLUSIONS: These findings revealed that hamstring presented different etiology and magnitude of neuromuscular fatigue compared with quadriceps. The absence of correlation observed between quadriceps and hamstring fatigue parameters (∆MVC, ∆P Tw , or ∆VA) suggests no interrelation in fatigue etiology between these two muscle groups within individuals and, therefore, highlights the need to investigate specifically hamstring muscle fatigue.

Chemotherapy impairs skeletal muscle mitochondrial homeostasis in early breast cancer patients.

BACKGROUND: Chemotherapy is extensively used to treat breast cancer and is associated with skeletal muscle deconditioning, which is known to reduce patients' quality of life, treatment efficiency, and overall survival. To date, skeletal muscle mitochondrial alterations represent a major aspect explored in breast cancer patients; nevertheless, the cellular mechanisms remain relatively unknown. This study was dedicated to investigating overall skeletal muscle mitochondrial homeostasis in early breast cancer patients undergoing chemotherapy, including mitochondrial quantity, function, and dynamics. METHODS: Women undergoing (neo)adjuvant anthracycline-cyclophosphamide and taxane-based chemotherapy participated in this study (56 ± 12 years). Two muscle biopsies were collected from the vastus lateralis muscle before the first and after the last chemotherapy administration. Mitochondrial respiratory capacity, reactive oxygen species production, and western blotting analyses were performed. RESULTS: Among the 11 patients, we found a decrease in key markers of mitochondrial quantity, reaching -52.0% for citrate synthase protein levels (P = 0.02) and -38.2% for VDAC protein levels (P = 0.04). This mitochondrial content loss is likely explained by reduced mitochondrial biogenesis, as evidenced by a decrease in PGC-1α1 protein levels (-29.5%; P = 0.04). Mitochondrial dynamics were altered, as documented by a decrease in MFN2 protein expression (-33.4%; P = 0.01), a key marker of mitochondrial outer membrane fusion. Mitochondrial fission is a prerequisite for mitophagy activation, and no variation was found in either key markers of mitochondrial fission (Fis1 and DRP1) or mitophagy (Parkin, PINK1, and Mul1). Two contradictory hypotheses arise from these results: defective mitophagy, which probably increases the number of damaged and fragmented mitochondria, or a relative increase in mitophagy through elevated mitophagic potential (Parkin/VDAC ratio; +176.4%; P < 0.02). Despite no change in mitochondrial respiratory capacity and COX IV protein levels, we found an elevation in H2 O2 production (P < 0.05 for all substrate additions) without change in antioxidant enzymes. We investigated the apoptosis pathway and found an increase in the protein expression of the apoptosis initiation marker Bax (+72.0%; P = 0.04), without variation in the anti-apoptotic protein Bcl-2. CONCLUSIONS: This study demonstrated major mitochondrial alterations subsequent to chemotherapy in early breast cancer patients: (i) a striking reduction in mitochondrial biogenesis, (ii) altered mitochondrial dynamics and potential mitophagy defects, (iii) exacerbated H2 O2 production, and (iv) increased initiation of apoptosis. All of these alterations likely explain, at least in part, the high prevalence of skeletal muscle and cardiorespiratory deconditioning classically observed in breast cancer patients.

Skeletal Muscle Deconditioning in Breast Cancer Patients Undergoing Chemotherapy: Current Knowledge and Insights From Other Cancers.

Breast cancer represents the most commonly diagnosed cancer while neoadjuvant and adjuvant chemotherapies are extensively used in order to reduce tumor development and improve disease-free survival. However, chemotherapy also leads to severe off-target side-effects resulting, together with the tumor itself, in major skeletal muscle deconditioning. This review first focuses on recent advances in both macroscopic changes and cellular mechanisms implicated in skeletal muscle deconditioning of breast cancer patients, particularly as a consequence of the chemotherapy treatment. To date, only six clinical studies used muscle biopsies in breast cancer patients and highlighted several important aspects of muscle deconditioning such as a decrease in muscle fibers cross-sectional area, a dysregulation of protein turnover balance and mitochondrial alterations. However, in comparison with the knowledge accumulated through decades of intensive research with many different animal and human models of muscle atrophy, more studies are necessary to obtain a comprehensive understanding of the cellular processes implicated in breast cancer-mediated muscle deconditioning. This understanding is indeed essential to ultimately lead to the implementation of efficient preventive strategies such as exercise, nutrition or pharmacological treatments. We therefore also discuss potential mechanisms implicated in muscle deconditioning by drawing a parallel with other cancer cachexia models of muscle wasting, both at the pre-clinical and clinical levels.

Evolution of Physical Status From Diagnosis to the End of First-Line Treatment in Breast, Lung, and Colorectal Cancer Patients: The PROTECT-01 Cohort Study Protocol.

Background: Cancer cachexia and exacerbated fatigue represent two hallmarks in cancer patients, negatively impacting their exercise tolerance and ultimately their quality of life. However, the characterization of patients' physical status and exercise tolerance and, most importantly, their evolution throughout cancer treatment may represent the first step in efficiently counteracting their development with prescribed and tailored exercise training. In this context, the aim of the PROTECT-01 study will be to investigate the evolution of physical status, from diagnosis to the end of first-line treatment, of patients with one of the three most common cancers (i.e., lung, breast, and colorectal). Methods: The PROTECT-01 cohort study will include 300 patients equally divided between lung, breast and colorectal cancer. Patients will perform a series of assessments at three visits throughout the treatment: (1) between the date of diagnosis and the start of treatment, (2) 8 weeks after the start of treatment, and (3) after the completion of first-line treatment or at the 6-months mark, whichever occurs first. For each of the three visits, subjective and objective fatigue, maximal voluntary force, body composition, cachexia, physical activity level, quality of life, respiratory function, overall physical performance, and exercise tolerance will be assessed. Discussion: The present study is aimed at identifying the nature and severity of maladaptation related to exercise intolerance in the three most common cancers. Therefore, our results should contribute to the delineation of the needs of each group of patients and to the determination of the most valuable exercise interventions in order to counteract these maladaptations. This descriptive and comprehensive approach is a prerequisite in order to elaborate, through future interventional research projects, tailored exercise strategies to counteract specific symptoms that are potentially cancer type-dependent and, in fine, to improve the health and quality of life of cancer patients. Moreover, our concomitant focus on fatigue and cachexia will provide insightful information about two factors that may have substantial interaction but require further investigation. Trial registration: This prospective study has been registered at ClinicalTrials.gov (NCT03956641), May, 2019.

C-Reactive Protein Level: A Key Predictive Marker of Cachexia in Lymphoma and Myeloma Patients.

BACKGROUND: Cachexia is defined as an involuntary loss of weight, characterized by a loss of skeletal muscle mass with or without fat mass loss. It increases mortality risk and decreases quality of life in patients with lymphoma or myeloma. Early markers of cachexia are not identified. The objective of this work was to identify risk factor of cachexia in a cohort of patients with hematological malignancies to develop strategies to prevent cachexia and its consequences. METHODS: Clinical and biological parameters were collected before and at the end of the treatment. Quantification of weight loss during cachexia was performed by the method of Martin. Clinical responses to treatment of patients with lymphoma or myeloma were monitored. RESULTS: Thirty-eight percent of the 145 patients enrolled were cachectic at the end of treatment. Classical prognostic disease scores at the time of diagnosis seemed to be not associated with cachexia observed at the end of treatment. Only C-reactive protein (CRP) > 54 mg/L seemed to be a risk factor of cachexia (P = 0.023, odds ratio (OR): 5.94 (1.55 - 39.14), confidence interval (CI): 1.55 - 39.14). Those results were confirmed by bootstrap analysis. CONCLUSION: This study highlights that high CRP level at diagnosis seems to be a risk factor for cachexia during treatment, permitting to identify patients at risk and in future to implement preventive strategies.