Branched-Chain Amino Acids and Di-Alanine Supplementation in Aged Mice: A Translational Study on Sarcopenia

In age-related sarcopenia, the gradual loss of skeletal muscle mass, function and strength is underpinned by an imbalanced rate of protein synthesis/breakdown. Hence, an adequate protein intake is considered a valuable strategy to mitigate sarcopenia. Here, we investigated the effects of a 12-week oral supplementation with branched-chain amino acids (BCAAs: leucine, isoleucine, and valine) with recognized anabolic properties, in 17-month-old (AGED) C57BL/6J male mice. BCAAs (2:1:1) were formulated in drinking water, alone or plus two L-Alanine equivalents (2ALA) or dipeptide L-Alanyl-L-Alanine (Di-ALA) to boost BCAAs bioavailability. Outcomes were evaluated on in/ex vivo readouts vs. 6-month-old (ADULT) mice. In vivo hind limb plantar flexor torque was improved in AGED mice treated with BCAAs + Di-ALA or 2ALA (recovery score, R.S., towards ADULT: ≥20%), and all mixtures significantly increased hind limb volume. Ex vivo, myofiber cross-sectional areas were higher in gastrocnemius (GC) and soleus (SOL) muscles from treated mice (R.S. ≥ 69%). Contractile indices of isolated muscles were improved by the mixtures, especially in SOL muscle (R.S. ≥ 20%). The latter displayed higher mTOR protein levels in mice supplemented with 2ALA/Di-ALA-enriched mixtures (R.S. ≥ 65%). Overall, these findings support the usefulness of BCAAs-based supplements in sarcopenia, particularly as innovative formulations potentiating BCAAs bioavailability and effects

Growth hormone secretagogues modulate inflammation and fibrosis in mdx mouse model of Duchenne muscular dystrophy

Introduction: Growth hormone secretagogues (GHSs) exert multiple actions, being able to activate GHS-receptor 1a, control inflammation and metabolism, to enhance GH/insulin-like growth factor-1 (IGF-1)-mediated myogenesis, and to inhibit angiotensin-converting enzyme. These mechanisms are of interest for potentially targeting multiple steps of pathogenic cascade in Duchenne muscular dystrophy (DMD). Methods: Here, we aimed to provide preclinical evidence for potential benefits of GHSs in DMD, via a multidisciplinary in vivo and ex vivo comparison in mdx mice, of two ad hoc synthesized compounds (EP80317 and JMV2894), with a wide but different profile. 4-week-old mdx mice were treated for 8 weeks with EP80317 or JMV2894 (320 μg/kg/d, s.c.). Results: In vivo, both GHSs increased mice forelimb force (recovery score, RS towards WT: 20% for EP80317 and 32% for JMV2894 at week 8). In parallel, GHSs also reduced diaphragm (DIA) and gastrocnemius (GC) ultrasound echodensity, a fibrosis-related parameter (RS: ranging between 26% and 75%). Ex vivo, both drugs ameliorated DIA isometric force and calcium-related indices (e.g., RS: 40% for tetanic force). Histological analysis highlighted a relevant reduction of fibrosis in GC and DIA muscles of treated mice, paralleled by a decrease in gene expression of TGF-β1 and Col1a1. Also, decreased levels of pro-inflammatory genes (IL-6, CD68), accompanied by an increment in Sirt-1, PGC-1α and MEF2c expression, were observed in response to treatments, suggesting an overall improvement of myofiber metabolism. No detectable transcript levels of GHS receptor-1a, nor an increase of circulating IGF-1 were found, suggesting the presence of a novel receptor-independent mechanism in skeletal muscle. Preliminary docking studies revealed a potential binding capability of JMV2894 on metalloproteases involved in extracellular matrix remodeling and cytokine production, such as ADAMTS-5 and MMP-9, overactivated in DMD. Discussion: Our results support the interest of GHSs as modulators of pathology progression in mdx mice, disclosing a direct anti-fibrotic action that may prove beneficial to contrast pathological remodeling

Management of acute pharyngitis in children: summary of the Italian National Institute of Health guidelines.

BACKGROUND: Discrepancies in the management of pharyngitis in children have been reported in Europe and the United States, and recommendations concerning the use of clinical scores, rapid antigen diagnostic tests (RADTs) or throat cultures, and the indications for antibiotic treatment largely differ. OBJECTIVE: This article summarizes the Italian guidelines on the management of pharyngitis in children issued by the National Institute of Health. METHODS: A multidisciplinary panel of experts (the Guidelines Development Group) developed and used a set of key questions to conduct a systematic review of the literature. Relevant publications in English were identified through a systematic review of MEDLINE and the Cochrane Database of Systematic Reviews from their inception through April 30, 2011. Final recommendations were scaled according to the Italian National Guidelines Program grading. RESULTS: Eighteen clinical questions were defined, and 44 recommendations were issued. None of the available scoring systems is sufficiently accurate to identify group A β-hemolytic streptococci (GABHS) pharyngitis in settings with low prevalence for rheumatic disease. RADT should be performed by trained personnel in every child with a history and signs/symptoms suggestive of GABHS pharyngitis. RADT is not recommended in children with a McIsaac score of 0 or 1 with ≥2 signs/symptoms suggestive of viral infection. Backup culture in children with negative RADT result is not recommended. Culture test with antibiotic susceptibility assay should be performed exclusively for epidemiologic purposes. Streptococcal antibody titers are of no value in diagnosing acute pharyngitis. Antibiotic therapy is recommended in microbiologically documented GABHS pharyngitis. Because penicillin V is not available in Italy, amoxicillin (50 mg/kg/d in 2-3 doses orally) for 10 days is the first choice of treatment. In noncompliant cases, benzathine penicillin may be administered. Although not routinely recommended due to the high cost and wide spectrum of activity, a 5-day course with a second-generation cephalosporin may be used in noncompliant cases. Macrolides should be limited to children with demonstrated type I hypersensitivity to penicillin. Ibuprofen or paracetamol is recommended for relief of pain or fever associated with discomfort. Because the carrier state is not associated with increased risk of suppurative complications and risk of GABHS transmission to contacts is minimal, the carrier state should never be investigated and treated. Recommendations for the management of suppurative complications are given. CONCLUSIONS: This guideline provides a comprehensive, evidence based, tool for the diagnosis and therapy of acute pharyngitis in children