From skeletal muscle damage and regeneration to the hypertrophy induced by exercise: what is the role of different macrophage subsets?

Macrophages are one of the top players when considering immune cells involved with tissue homeostasis. Recently, increasing evidence has demonstrated that macrophages could also present two major subsets during tissue healing: proliferative macrophages (M1-like), which are responsible for increasing myogenic cell proliferation, and restorative macrophages (M2-like), which are involved in the end of the mature muscle myogenesis. The participation and characterization of these macrophage subsets are critical during myogenesis to understand the inflammatory role of macrophages during muscle recovery and to create supportive strategies that can improve mass muscle maintenance. Indeed, most of our knowledge about macrophage subsets comes from skeletal muscle damage protocols, and we still do not know how these subsets can contribute to skeletal muscle adaptation. Thus, this narrative review aims to collect and discuss studies demonstrating the involvement of different macrophage subsets during the skeletal muscle damage/regeneration process, showcasing an essential role of these macrophage subsets during muscle adaptation induced by acute and chronic exercise programs.

Hemiagenesia tiroidea: caso clínico y revisión de la literatura / Thyroid hemiagenesis: clinical case and review of the literature

La hemiagenesia tiroidea representa un trastorno congénito caracterizado por la ausencia de desarrollo de uno de los lóbulos tiroideos, asociado o no a ausencia del istmo. Es más frecuente en las mujeres y por lo general se presenta como falta del lóbulo izquierdo, con hipertrofia compensatoria del lóbulo contralateral. Su diagnóstico es generalmente incidental o por manifestaciones del lóbulo tiroideo presente. Se hizo una revisión bibliografía, en donde no se encontraron casos reportados en Venezuela de hemiagenesia o agenesia tiroidea, describiéndose el siguiente. Presentamos a una paciente de 50 años de edad, conocida con hipotiroidismo desde los 31 años, negando cualquier cirugía en el área de cabeza y cuello. Desde febrero 2019 presentó aumento progresivo de volumen en región anterior de cuello. Al examen físico se observó aumento de volumen en región anterior derecha del cuello, palpándose lóbulo tiroideo derecho aumentado de tamaño, de aspecto nodular, no doloroso. En ecosonograma tiroideo se concluyó como bocio tiroideo derecho de aspecto multinodular, con ausencia del lóbulo izquierdo. Perfil tiroideo dentro de límites normales. Se lleva a mesa operatoria corroborándose ausencia del lóbulo izquierdo y presentado en la biopsia definitiva hiperplasia nodular en el lóbulo derecho. Se discute su frecuencia, la forma de presentación y se hace revisión de la literatura(AU)

Thyroid hemiagenesis represents a congenital disorder characterized by the absence of development of one of thyroid lobes, associated or not with absence of isthmus. It is more frequent in women and generally presents as absence of the left lobe, with compensatory hypertrophy of the contralateral lobe. Its diagnosis is generally incidental or by manifestations of the present thyroid lobe. A bibliography review was made, where no cases reported in Venezuela of hemiagenesis or thyroid agenesis were found, describing the following. We present a 50-year-old patient, known with hypothyroidism since she was 31, denying any surgery in the head and neck area. Since February 2019, presented a progressive increase in volume in the anterior neck region. On physical examination, an increase in volume was observed in right anterior region of the neck, palpating an enlarged right thyroid lobe, with a nodular appearance and not painful. In a thyroid echo-sonogram, it was concluded as a right thyroid goiter with a multinodular appearance, with the absence of the left lobe. Thyroid profile within normal limits. It is taken to the operating table, confirming the absence of the left lobe and presented in the definitive biopsy nodular hyperplasia in the right lobe. Its frequency, form of presentation, and literature review are discussed(AU)

Changes in the lateral abdominal wall following endoscopic subcutaneous anterior component separation.

PURPOSE: Although changes in lateral abdominal wall musculature after posterior component separation with transversus abdominis release have been investigated, the effects of endoscopic subcutaneous anterior component separation (ES-ACS) on postoperative muscle anatomy have not been evaluated. The purpose of this study was to evaluate changes in the lateral abdominal muscles after ES-ACS. METHODS: Computed tomography (CT) images of patients who underwent ES-ACS were retrospectively evaluated. Lateral abdominal wall thickness and external oblique displacement were measured at the level of fixed retroperitoneal structures. Measurements on the ES-ACS side were compared with those on the contralateral undivided side or with preoperative images in patients with bilateral procedures. RESULTS: Fifteen patients met the criteria for study inclusion. Most patients (n = 13, 86.7%) underwent unilateral ES-ACS. The most commonly performed procedure was laparoscopic intraperitoneal onlay mesh-plus hernia repair (n = 12, 80.0%; the remaining patients underwent open repair). The Mean defect width was 8.4 cm (range 6-15 cm). There was no difference in the thickness of the lateral abdominal musculature between ES-ACS and undivided sides. There was a significant lateral displacement of the external oblique muscle from the lateral edge of the rectus abdominis on the ES-ACS side (mean distance 3.7 cm; p = 0.0006). No midline hernia recurrences, iatrogenic linea semilunaris hernias, or lateral eventrations were observed during a mean follow-up period of 2.6 years (range 0.5-7.4 years). CONCLUSION: ES-ACS resulted in no atrophy of the lateral abdominal muscles in long-term CT follow-up. The procedure is a safe and effective adjunct to complex hernia repair in selected patients.

Concomitant Anterior and Posterior Component Separations: Absolutely Contraindicated?

Many experts in abdominal wall reconstruction believe that the combination of simultaneous ipsilateral anterior component separation (ACS) and posterior component separation (PCS) is contraindicated. We performed ipsilateral endoscopic ACS and either endoscopic or open PCS-transversus abdominis release (TAR) in 5 fresh cadaver models. The full length of the semilunar line and the lateral abdominal wall remained well reinforced by 2 complete layers, comprising the internal oblique (IO) and TA muscles and their investing fasciae. Myofascial releases occurred 4 cm (median) apart. Additionally, we reviewed computed tomography images at 1 month and 1 year after PCS-TAR in 17 patients (30 PCS-TARs). Lateral displacement of the TA relative to the rectus abdominis (RA) was significant only at the superior mesenteric artery level, where it was <1 cm (median). Muscle mass changed minimally over time. Several studies showed that abdominal wall reconstruction after PCS-TAR results in compensatory muscular hypertrophy of the RA, external oblique (EO), and IO muscles and provides better quality of life and improved core physiology. These changes did not occur when the midline was not restored. Theoretically, endoscopic ACS-EO may be added to PCS-TAR to avoid partially bridged mesh repair in patients in whom complete midline restoration is impossible via PCS-TAR alone. Nevertheless, we advise most surgeons to perform a small-bridged repair instead of risking increased morbidity by attempting a highly complicated procedure.

Systematic review of the synergist muscle ablation model for compensatory hypertrophy / Revisão sistemática do modelo de ablação dos músculos sinérgicos na hipertrofia compensatória

Summary Objective: The aim was to evaluate the effectiveness of the experimental synergists muscle ablation model to promote muscle hypertrophy, determine the period of greatest hypertrophy and its influence on muscle fiber types and determine differences in bilateral and unilateral removal to reduce the number of animals used in this model. Method: Following the application of the eligibility criteria for the mechanical overload of the plantar muscle in rats, nineteen papers were included in the review. Results: The results reveal a greatest hypertrophy occurring between days 12 and 15, and based on the findings, synergist muscle ablation is an efficient model for achieving rapid hypertrophy and the contralateral limb can be used as there was no difference between unilateral and bilateral surgery, which reduces the number of animals used in this model. Conclusion: This model differs from other overload models (exercise and training) regarding the characteristics involved in the hypertrophy process (acute) and result in a chronic muscle adaptation with selective regulation and modification of fast-twitch fibers in skeletal muscle. This is an efficient and rapid model for compensatory hypertrophy.

Resumo Objetivo: Avaliar a eficácia do modelo experimental de ablação dos sinergistas para promover a hipertrofia muscular, determinar o período de maior hipertrofia, sua influência sobre os tipos de fibras musculares e determinar diferenças na remoção unilateral ou bilateral para reduzir o número de animais utilizados nesse modelo. Método: Após a aplicação dos critérios de elegibilidade para sobrecarga mecânica do músculo plantar em ratos, 19 artigos foram incluídos na revisão. Resultados: Ocorre maior hipertrofia entre os dias 12 e 15, o que torna o modelo eficiente para alcançar a hipertrofia rapidamente. O membro contralateral também pode ser usado, pois não houve diferença entre a cirurgia unilateral e bilateral, o que reduz o número de animais usados no experimento. Conclusão: O modelo difere de outros modelos de sobrecarga (exercício e treinamento) em razão das características envolvidas no processo de sobrecarga imposta (aguda), resultando em uma adaptação crônica muscular com modificação de fibras de contração rápida do músculo esquelético. É um modelo rápido e eficiente para se estudar hipertrofia compensatória.