Anti-inflammatory nutrition with high protein attenuates cardiac and skeletal muscle alterations in a pulmonary arterial hypertension model

Histological changes in skeletal muscle induced by heart failure in human patients and animal models: A scoping review

OBJECTIVE

This scoping review aimed to characterize the histological changes in skeletal muscle after heart failure (HF) and to identify gaps in knowledge.

METHODS

On April 03, 2024, systematic searches were performed for papers in which histological analyses were conducted on skeletal muscle sampled from patients with HF or animal models of HF. Screening and data extraction were conducted by two independent authors.

RESULTS AND CONCLUSION

A total of 118 papers were selected, including 33 human and 85 animal studies. Despite some disagreements among studies, some trends were observed. These trends included a slow-to-fast transition, a decrease in muscle fiber size, capillary to muscle fiber ratio, and mitochondrial activity and content, and an increase in apoptosis. These changes may contribute to the fatigability and decrease in muscle strength observed after HF. Although there were some disagreements between the results of human and animal studies, the results were generally similar. Animal models of HF will therefore be useful in elucidating the histological changes in skeletal muscle that occur in human patients with HF. Because the muscles subjected to histological analysis were mostly thigh muscles in humans and mostly lower leg muscles in animals, it remains uncertain whether changes similar to those seen in lower limb (hindlimb) muscles after HF also occur in upper limb (forelimb) muscles. The results of this review will consolidate the current knowledge on HF-induced histological changes in skeletal muscle and consequently aid in the rehabilitation of patients with HF and future studies.

Differences in impact on disease or lung injury depending on the physicochemical characteristics of harmful chemicals in the PAH model

The number of individuals with underlying medical conditions has been increasing steadily. These individuals are relatively vulnerable to harmful external factors. But it has not been proven that the effects of hazardous chemicals may differ depending on their physicochemical properties. This study determines the toxic effects of two chemicals with high indoor exposure risk and different physicochemical properties on an underlying disease model. A pulmonary arterial hypertension (PAH) model was constructed by a single subcutaneous injection of monocrotaline (MCT; 60 mg/kg) into Sprague-Dawley rats. After three weeks, formaldehyde (FA; 2.5 mg/kg) and polyhexamethylene guanidine (PHMG; 0.05 mg/kg) were administered once via intratracheal instillation, and rats were necropsied one week later. Exposure to FA and PHMG affected organ weight and the Fulton and toxicity indices in rats induced with PAH. FA promoted bronchial injury and aggravated PAH, while PHMG only induced alveolar injury. Additionally, the differentially expressed genes were altered following exposure to FA and PHMG, as were the associated diseases (cardiovascular disease and pulmonary fibrosis, respectively). In conclusion, inhaled chemicals with different physicochemical properties can cause damage to organs, such as the lungs and heart, and can aggravate underlying diseases. This study elucidates indoor inhaled exposure-induced toxicities and alerts patients with pre-existing diseases to the harmful chemicals.

Controlling Nutritional Status Score Predicts 1-Year Outcomes in Chronic Thromboembolic Pulmonary Hypertension

Background

The prognosis for patients with chronic thromboembolic pulmonary hypertension (CTEPH) using their nutritional status has not been established. We investigated the relationship between the prognosis of patients with CTEPH and the Controlling Nutritional Status (CONUT) score, which is a nutritional assessment tool.

Methods and Results

A total of 157 patients with CTEPH was enrolled in the study. The primary outcome was defined as the composite outcome of all-cause mortality and non-elective hospitalization due to heart failure. Receiver operating characteristic (ROC) curve analysis was used to determine the cutoff CONUT score for predicting the 1-year rate of the primary outcome. Patients were divided into 2 groups according to the significant cutoff value and compared. Undernutrition was observed in 51.6% of patients. ROC analysis revealed a significant cutoff CONUT score of 3.5 (area under the curve=0.789). The incidence rate of the primary composite outcome was higher in the high CONUT group (score ≥4) than in the low CONUT group (score ≤3; 20% vs. 2.2%; P<0.001). Cox analysis revealed the CONUT score per point increase was an independent risk factor for the primary composite outcomes (hazard ratio 2.301; 95% confidence interval 1.081-4.895; P=0.031).

Conclusions

The CONUT score can predict the 1-year rate of all-cause death and non-elective hospitalization in patients with CTEPH.

Gut-Lung Axis in Focus: Deciphering the Impact of Gut Microbiota on Pulmonary Arterial Hypertension

Recent advancements in the understanding of pulmonary arterial hypertension (PAH) have highlighted the significant role of the gut microbiota (GM) in its pathogenesis. This comprehensive review delves into the intricate relationship between the GM and PAH, emphasizing the influence of gut microbial composition and the critical metabolites produced. We particularly focus on the dynamic interaction between the gut and lung, examining how microbial dysbiosis contributes to PAH development through inflammation, altered immune responses, and changes in the gut-lung axis. Noteworthy findings include variations in the ratios of key bacterial groups such as Firmicutes and Bacteroidetes in PAH and the pivotal roles of metabolites like trimethylamine N-oxide (TMAO), short-chain fatty acids (SCFAs), and serotonin in the disease's progression. Additionally, the review elucidates potential diagnostic biomarkers and novel therapeutic approaches, including the use of probiotics and fecal microbiota transplantation, which leverage the gut microbiota for managing PAH. This review encapsulates the current state of research in this field, offering insights into the potential of gut microbiota modulation as a promising strategy in PAH diagnosing and treatment.

Pharmacological effects of Bufei Jianpi granule on chronic obstructive pulmonary disease and its metabolism in rats

This work was performed to determine the pharmacological effects of Bufei Jianpi granules on chronic obstructive pulmonary disease and its metabolism in rats. Chronic obstructive pulmonary disease (COPD), ranked as the third leading cause of death worldwide, is seriously endangering human health. At present, the pathogenesis of COPD is complex and unclear, and the drug treatment mainly aims to alleviate and improve symptoms; however, they cannot achieve the purpose of eradicating the disease. Bufei Jianpi granule (BJG) is a Chinese medicine developed by the First Affiliated Hospital of Henan University of Traditional Chinese Medicine for treating COPD. This study focuses on the pharmacological effects of BJG on COPD and its metabolism in rats, aiming to provide a scientific basis for developing BJG against COPD. A total of 72 Sprague-Dawley (SD) rats were divided into the blank group, model group, positive control group, and BJG groups (2.36, 1.18, and 0.59 g/kg). Except for the blank group, rats in other groups were administered lipopolysaccharide (LPS) combined with smoking for 6 weeks to establish the COPD model. After another 6 weeks of treatment, the therapeutic effect of BJG on COPD rats was evaluated. In the BJG (2.36 g/kg) group, the cough condition of rats was significantly relieved and the body weight was close to that of the blank group. Compared with the mortality of 16.7% in the model group, no deaths occurred in the BJG (2.36 g/kg) and (1.18 g/kg) groups. The lung tissue damage in the BJG groups was less than that in the COPD group. Compared with the model group, MV, PIF, PEF, and EF50 in the BJG groups were observably increased in a dose-dependent manner, while sRaw, Raw, and FRC were obviously decreased. Also, the contents of IL-6, IL-8, TNF-α, PGE2, MMP-9, and NO in the serum and BALF were lowered dramatically in all BJG groups. All indicators present an obvious dose-effect relationship. On this basis, the UPLC-QTOF-MS/MS technology was used to analyze characteristic metabolites in rats under physiological and pathological conditions. A total of 17 prototype and 7 metabolite components were detected, and the concentration of most components was increased in the COPD pathologic state. It is suggested that BJG has a pharmacological effect in the treatment of COPD and the absorption and metabolism of chemical components of BJG in rats exhibited significant differences under physiological and pathological conditions.

Evaluation of the recovery after heart surgery following preoperative supplementation with a combination of beta-hydroxy-beta-methylbutyrate, L-arginine, and L-glutamine: a double-blind randomized placebo-controlled clinical trial

BACKGROUND

The preoperative period is a good time to improve nutrition status, compensate for nutrient deficiencies, and optimize immune function in patients' underlying surgery. In some medical conditions, supplementation with a combination of L-glutamine (Gln), β-hydroxy-β-methylbutyrate (HMB), and L-arginine (Arg) had promising effects on improving recovery. The present study aimed to evaluate the effect of supplementation with Gln/Arg/HMB in patients undergoing heart surgery.

METHODS

This randomized clinical trial was conducted on 70 patients undergoing cardiac surgery. Participants were requested to consume 2 sachets of a combination of 7 g L-arginine, 7 g L-glutamine, and 1.5 g daily HMB or placebo 30 days before operation. At the baseline and end of the study, left ventricular ejection fraction and the serum levels of troponin, creatine phosphokinase (CPK), CPK-MB, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin were measured. Also, the Sequential Organ Failure Assessment (SOFA) score, time of stay in hospital and intensive care unit (ICU), and postoperative complications were recorded after surgery.

RESULTS

In total, 60 preoperative patients (30 in each group) with a mean age of 53.13 ± 14.35 years completed the study (attrition rate = 85.7%). Subjects in the Gln/Arg/HMB group had lower serum levels of CPK-MB (median [IQR] = 49 [39.75] vs. 83 [64.55]; P = 0.011), troponin (median [IQR] = 2.13 [1.89] vs. 4.34 [1.99]; P < 0.001), bilirubin (median [IQR] = 0.50 [0.20] vs. 0.40 [0.22]; P < 0.001), and SOFA score (median [IQR] = 2 [2] vs. 5 [2]; P < 0.001) at end of the study compared to the placebo. Also, the time of stay in the hospital (median [IQR] = 5 [1] vs. 6 [3]; P < 0.001) and ICU (median [IQR] = 2.50 [1.00] vs. 3.50 [1.50]; P = 0.002) was lower in the Gln/Arg/HMB group.

CONCLUSION

The present study showed that perioperative supplementation with a combination of Gln, Arg, and HMB enhances the recovery, reduces myocardial injury, and decreases the time of hospital and ICU stay in cardiac surgery patients. These results need to be confirmed in a larger trial.

TRIAL REGISTRATION

IRCT.ir IRCT20120913010826N31. Registered on 13 October 2020.

The effects of preoperative supplementation with a combination of beta-hydroxy-beta-methylbutyrate, arginine, and glutamine on inflammatory and hematological markers of patients with heart surgery: a randomized controlled trial

Background

Cardiac surgery is associated with a widespread inflammatory response, by an additional release of free radicals. Due to the importance of these patient’s nutritional status, the present study was designed to evaluate the effectiveness of supplementation with a combination of glutamine, β-hydroxy-β-methylbutyrate (HMB) and arginine in patients undergoing to the heart surgery.

Methods

The experiment was performed in 1 month (30 days) before cardiac surgery. patients were asked to take 2 sachets of Heallagen® (a combination of 7 g l-arginine, 7 g l-glutamine, and 1.5 g daily HMB) or placebo with identical appearance and taste (maltodextrin) with 120 cc of water. Clinical and biochemical factors were evaluated in the baseline and end of the study.

Results

Totally, 60 preoperative patients (30 interventions and 30 placeboes) with a mean age of 53.13 ± 14.35 years participated in the study. Subjects in Heallagen® group had a lower serum levels of interleukin-6 (P = 0.023), erythrocyte sedimentation rate (P < 0.01), high sensitivity C-reactive protein (P < 0.01), and lymphocyte number (P = 0.007) compared to the placebo, at end of the study.

Conclusion

In the patients undergoing heart surgery, Heallagen® significantly improved some of the inflammatory factors and hematological parameters. These results need to be confirmed in a larger trial.

Trial registration: The protocol of the study was registered in the IRCT.ir with registration no. IRCT20120913010826N31 at 13/10/2020.

Exercise intolerance in pulmonary arterial hypertension: insight into central and peripheral pathophysiological mechanisms

Exercise intolerance is a cardinal symptom of pulmonary arterial hypertension (PAH) and strongly impacts patients' quality of life (QoL). Although central cardiopulmonary impairments limit peak oxygen consumption (V' O2peak ) in patients with PAH, several peripheral abnormalities have been described over the recent decade as key determinants in exercise intolerance, including impaired skeletal muscle (SKM) morphology, convective O2 transport, capillarity and metabolism indicating that peripheral abnormalities play a greater role in limiting exercise capacity than previously thought. More recently, cerebrovascular alterations potentially contributing to exercise intolerance in patients with PAH were also documented. Currently, only cardiopulmonary rehabilitation has been shown to efficiently improve the peripheral components of exercise intolerance in patients with PAH. However, more extensive studies are needed to identify targeted interventions that would ultimately improve patients' exercise tolerance and QoL. The present review offers a broad and comprehensive analysis of the present literature about the complex mechanisms and their interactions limiting exercise in patients and suggests several gaps in knowledge that need to be addressed in the future for a better understanding of exercise intolerance in patients with PAH.

Restoration of Vitamin D Levels Improves Endothelial Function and Increases TASK-Like K+ Currents in Pulmonary Arterial Hypertension Associated with Vitamin D Deficiency

Background: Vitamin D (vitD) deficiency is highly prevalent in patients with pulmonary arterial hypertension (PAH). Moreover, PAH-patients with lower levels of vitD have worse prognosis. We hypothesize that recovering optimal levels of vitD in an animal model of PAH previously depleted of vitD improves the hemodynamics, the endothelial dysfunction and the ionic remodeling. Methods: Male Wistar rats were fed a vitD-free diet for five weeks and then received a single dose of Su5416 (20 mg/Kg) and were exposed to vitD-free diet and chronic hypoxia (10% O₂) for three weeks to induce PAH. Following this, vitD deficient rats with PAH were housed in room air and randomly divided into two groups: (a) continued on vitD-free diet or (b) received an oral dose of 100,000 IU/Kg of vitD plus standard diet for three weeks. Hemodynamics, pulmonary vascular remodeling, pulmonary arterial contractility, and K⁺ currents were analyzed. Results: Recovering optimal levels of vitD improved endothelial function, measured by an increase in the endothelium-dependent vasodilator response to acetylcholine. It also increased the activity of TASK-1 potassium channels. However, vitD supplementation did not reduce pulmonary pressure and did not ameliorate pulmonary vascular remodeling and right ventricle hypertrophy. Conclusions: Altogether, these data suggest that in animals with PAH and severe deficit of vitD, restoring vitD levels to an optimal range partially improves some pathophysiological features of PAH.

Firearms-related skeletal muscle trauma: pathophysiology and novel approaches for regeneration

One major cause of traumatic injury is firearm-related wounds (i.e., ballistic trauma), common in both civilian and military populations, which is increasing in prevalence and has serious long-term health and socioeconomic consequences worldwide. Common primary injuries of ballistic trauma include soft-tissue damage and loss, haemorrhage, bone fracture, and pain. The majority of injuries are of musculoskeletal origin and located in the extremities, such that skeletal muscle offers a major therapeutic target to aid recovery and return to normal daily activities. However, the underlying pathophysiology of skeletal muscle ballistic trauma remains poorly understood, with limited evidence-based treatment options. As such, this review will address the topic of firearm-related skeletal muscle injury and regeneration. We first introduce trauma ballistics and the immediate injury of skeletal muscle, followed by detailed coverage of the underlying biological mechanisms involved in regulating skeletal muscle dysfunction following injury, with a specific focus on the processes of muscle regeneration, muscle wasting and vascular impairments. Finally, we evaluate novel approaches for minimising muscle damage and enhancing muscle regeneration after ballistic trauma, which may have important relevance for primary care in victims of violence.

Differential effects of right and left heart failure on skeletal muscle in rats

BACKGROUND

Exercise intolerance is a cardinal symptom in right (RV) and left ventricular (LV) failure. The underlying skeletal muscle contributes to increased morbidity in patients. Here, we compared skeletal muscle sarcopenia in a novel two-stage model of RV failure to an established model of LV failure.

METHODS

Pulmonary artery banding (PAB) or aortic banding (AOB) was performed in weanling rats, inducing a transition from compensated cardiac hypertrophy (after 7 weeks) to heart failure (after 22-26 weeks). Cardiac function was characterized by echocardiography. Skeletal muscle catabolic/anabolic balance and energy metabolism were analysed by histological and biochemical methods, real-time PCR, and western blot.

RESULTS

Two clearly distinguishable stages of left or right heart disease with a comparable severity were reached. However, skeletal muscle impairment was significantly more pronounced in LV failure. While the compensatory stage resulted only in minor changes, soleus and gastrocnemius muscle of AOB rats at the decompensated stage demonstrated reduced weight and fibre diameter, higher proteasome activity and expression of the muscle-specific ubiquitin E3 ligases muscle-specific RING finger 1 and atrogin-1, increased expression of the atrophy marker myostatin, increased autophagy activation, and impaired mitochondrial function and respiratory chain gene expression. Soleus and gastrocnemius muscle of PAB rats did not show significant changes in muscle weight and proteasome or autophagy activation, but mitochondrial function was mildly impaired as well. The diaphragm did not demonstrate differences in any model or disease stage except for myostatin expression, which was altered at the decompensated stage in both models. Plasma interleukin (IL)-6 and angiotensin II were strongly increased at the decompensated stage (AOB > > PAB). Soleus and gastrocnemius muscle itself demonstrated an increase in IL-6 expression independent from blood-derived cytokines only in AOB animals. In vitro experiments in rat skeletal muscle cells suggested a direct impact of IL-6 and angiotensin II on distinctive atrophic changes.

CONCLUSIONS

Manifold skeletal muscle alterations are more pronounced in LV failure compared with RV failure despite a similar ventricular impairment. Most of the catabolic changes were observed in soleus or gastrocnemius muscle rather than in the constantly active diaphragm. Mitochondrial dysfunction and up-regulation of myostatin were identified as the earliest signs of skeletal muscle impairment.

Expression of MuRF1 or MuRF2 is essential for the induction of skeletal muscle atrophy and dysfunction in a murine pulmonary hypertension model

BACKGROUND

Pulmonary hypertension leads to right ventricular heart failure and ultimately to cardiac cachexia. Cardiac cachexia induces skeletal muscles atrophy and contractile dysfunction. MAFbx and MuRF1 are two key proteins that have been implicated in chronic muscle atrophy of several wasting states.

METHODS

Monocrotaline (MCT) was injected over eight weeks into mice to establish pulmonary hypertension as a murine model for cardiac cachexia. The effects on skeletal muscle atrophy, myofiber force, and selected muscle proteins were evaluated in wild-type (WT), MuRF1, and MuRF2-KO mice by determining muscle weights, in vitro muscle force and enzyme activities in soleus and tibialis anterior (TA) muscle.

RESULTS

In WT, MCT treatment induced wasting of soleus and TA mass, loss of myofiber force, and depletion of citrate synthase (CS), creatine kinase (CK), and malate dehydrogenase (MDH) (all key metabolic enzymes). This suggests that the murine MCT model is useful to mimic peripheral myopathies as found in human cardiac cachexia. In MuRF1 and MuRF2-KO mice, soleus and TA muscles were protected from atrophy, contractile dysfunction, while metabolic enzymes were not lowered in MuRF1 or MuRF2-KO mice. Furthermore, MuRF2 expression was lower in MuRF1KO mice when compared to C57BL/6 mice.

CONCLUSIONS

In addition to MuRF1, inactivation of MuRF2 also provides a potent protection from peripheral myopathy in cardiac cachexia. The protection of metabolic enzymes in both MuRF1KO and MuRF2KO mice as well as the dependence of MuRF2 expression on MuRF1 suggests intimate relationships between MuRF1 and MuRF2 during muscle atrophy signaling.

Impact of Nutrition on Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by sustained vasoconstriction, vascular remodeling, inflammation, and in situ thrombosis. Although there have been important advances in the knowledge of the pathophysiology of PAH, it remains a debilitating, limiting, and rapidly progressive disease. Vitamin D and iron deficiency are worldwide health problems of pandemic proportions. Notably, these nutritional alterations are largely more prevalent in PAH patients than in the general population and there are several pieces of evidence suggesting that they may trigger or aggravate disease progression. There are also several case reports associating scurvy, due to severe vitamin C deficiency, with PAH. Flavonoids such as quercetin, isoflavonoids such as genistein, and other dietary polyphenols including resveratrol slow the progression of the disease in animal models of PAH. Finally, the role of the gut microbiota and its interplay with the diet, host immune system, and energy metabolism is emerging in multiple cardiovascular diseases. The alteration of the gut microbiota has also been reported in animal models of PAH. It is thus possible that in the near future interventions targeting the nutritional status and the gut dysbiosis will improve the outcome of these patients.