Autophagy regulates the release of exercise factors and their beneficial effects on spatial memory recall

Exercise promotes learning and memory recall as well as rescues cognitive decline associated with aging. The positive effects of exercise are mediated by circulatory factors that predominantly increase Brain Derived Neurotrophic Factor (BDNF) signaling in the hippocampus. Identifying the pathways that regulate the release of the circulatory factors by various tissues during exercise and that mediate hippocampal Mus musculus Bdnf expression will allow us to harness the therapeutic potential of exercise. Here, we report that two weeks of voluntary exercise in male mice activates autophagy in the hippocampus by increasing LC3B protein levels (p = 0.0425) and that autophagy is necessary for exercise-induced spatial learning and memory retention (p < 0.001; exercise + autophagy inhibitor chloroquine CQ versus exercise). We place autophagy downstream of hippocampal BDNF signaling and identify a positive feedback activation between the pathways. We also assess whether the modulation of autophagy outside the nervous system is involved in mediating exercise's effect on learning and memory recall. Indeed, plasma collected from young exercise mice promote spatial learning (p = 0.0446; exercise versus sedentary plasma) and memory retention in aged inactive mice (p = 0.0303; exercise versus sedentary plasma), whereas plasma collected from young exercise mice that received the autophagy inhibitor chloroquine diphosphate failed to do so. We show that the release of exercise factors that reverse the symptoms of aging into the circulation is dependent on the activation of autophagy in young animals. Indeed, we show that the release of the exercise factor, beta-hydroxybutyrate (DBHB), into the circulation, is autophagy-dependent and that DBHB promotes spatial learning and memory formation (p = 0.0005) by inducing hippocampal autophagy (p = 0.0479). These results implicate autophagy in peripheral tissues and in the hippocampus in mediating the effects of exercise on learning and memory recall and identify DBHB as a candidate endogenous exercise factor whose release and positive effects are autophagy-dependent.

Branched-chain amino acids mediate resilience to chronic social defeat stress by activating BDNF/TRKB signaling

How individuals respond to chronic stress varies. Susceptible individuals ultimately develop depression; whereas resilient individuals live normally. In this study, our objective was to examine the effect of branched-chain amino acids (BCAA), commonly used by athletes, on susceptibility to stress. Male C57BL/6 mice were subjected to daily defeat sessions by a CD1 aggressor, for 10 days. On day11, the behavior of mice was assessed using the social interaction test, elevated plus maze and open field. Mice received the BCAA leucine, isoleucine or valine before each defeat session. Furthermore, we examined whether BCAA regulate brain derived neurotrophic factor (BDNF) signaling by using a brain-permeable tropomyosin receptor kinase B (TRKB) inhibitor, ANA-12. We also tested the effect of voluntary exercise and high protein diets on susceptibility to stress. Mice exposed to chronic stress displayed increased susceptibility and social avoidance. BCAA promoted resilience to chronic stress, rescued social avoidance behaviors and increased hippocampal BDNF levels and TRKB activation. Inhibition of TRKB signaling abolished the ability of BCAA to promote resilience to stress and to rescue social avoidance. Interestingly, we found that BCAA activate the exercise-regulated PGC1a/FNDC5 pathway known to induce hippocampal BDNF signaling. Although both voluntary exercise and BCAA promoted resilience to stress, combining them did not yield synergistic effects confirming that they affect similar pathways. We also discovered that high protein diets mimic the effect of BCAA by rescuing social deficits induced by chronic stress and increase Bdnf expression in the hippocampus. Our data indicate that BCAA, exercise and high protein diets rescue susceptibility to stress by activating the hippocampal BDNF/TRKB signaling.

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BCAA promote resilience to stress and rescue social avoidance via activation of hippocampal BDNF/TRKB signaling.

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BCAA induce hippocampal BDNF/TRKB signaling by activating the exercise-regulated PGC1a/FNDC5 pathway.

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BCAA and voluntary exercise affect similar pathways.

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HPD promote resilience to stress, rescue social avoidance and induce hippocampal Bdnf expression.

Lactate is an antidepressant that mediates resilience to stress by modulating the hippocampal levels and activity of histone deacetylases

Chronic stress promotes depression in some individuals, but has no effect in others. Susceptible individuals exhibit social avoidance and anxious behavior and ultimately develop depression, whereas resilient individuals live normally. Exercise counteracts the effects of stress. Our objective was to examine whether lactate, a metabolite produced during exercise and known to reproduce specific brain exercise-related changes, promotes resilience to stress and acts as an antidepressant. To determine whether lactate promotes resilience to stress, male C57BL/6 mice experienced daily defeat by a CD-1 aggressor, for 10 days. On the 11th day, mice were subjected to behavioral tests. Mice received lactate before each defeat session. When compared with control mice, mice exposed to stress displayed increased susceptibility, social avoidance and anxiety. Lactate promoted resilience to stress and rescued social avoidance and anxiety by restoring hippocampal class I histone deacetylase (HDAC) levels and activity, specifically HDAC2/3. To determine whether lactate is an antidepressant, mice only received lactate from days 12-25 and a second set of behavioral tests was conducted on day 26. In this paradigm, we examined whether lactate functions by regulating HDACs using co-treatment with CI-994, a brain-permeable class I HDAC inhibitor. When administered after the establishment of depression, lactate behaved as antidepressant. In this paradigm, lactate regulated HDAC5 and not HDAC2/3 levels. On the contrary, HDAC2/3 inhibition was antidepressant-like. This indicates that lactate mimics exercise's effects and rescues susceptibility to stress by modulating HDAC2/3 activity and suggests that HDAC2/3 play opposite roles before and after establishment of susceptibility to stress.

Testicular health awareness in pubertal males

PURPOSE

We examined the knowledge and understanding of male teenagers of the necessity for genital examination, and signs and symptoms of serious testicular pathology. Furthermore, current national guidelines for health education were reviewed to understand better the curriculum used by the educational system and to assess its effectiveness.

MATERIALS AND METHODS

In 1998, a 5-question survey was administered privately and confidentially to male athletes before a sports physical examination. The athletes were 12 to 18 years old, attended middle or high school, and were sampled randomly. The National Health Education Standards benchmark for grades 9 through 11 was examined with specific attention to male self-health education standards.

RESULTS

A total of 318 athletes responded revealing that 54% did not know why the genitals were examined on a sports physical examination, 45% did not use appropriate testicular protection and the majority did not respond appropriately to symptoms of serious testicular pathology. Despite the fact that 46% of respondents answered that checking for a hernia is reason for a genital examination there was no mention of tumor, infection or varicocele. Review of the benchmarks revealed no standards referring to a minimum understanding of anatomy or physiology. Generalized guidelines for high risk behaviors were provided without specific mention of testicular torsion, cancer, varicocele or sexually transmitted diseases.

CONCLUSIONS

Young males are at higher risk for testicular torsion, cancer and varicocele than other age groups, and yet our population was universally unaware of these as a reason for genital examination. Furthermore, the majority did not respond appropriately to questions regarding serious testicular pathology. Review of national guidelines reveals poorly defined, nonspecific provisions for male self-health care. Therefore, we have developed a curriculum for male self-health to address this problem.

Prepubertal varicoceles

OBJECTIVES

Varicoceles are rarely detected in prepubertal boys. In an effort to further determine the natural history of prepubertal varicoceles, we have reviewed our experience with prepubertal boys who had varicoceles.

METHODS

Eleven patients with prepubertal varicoceles were seen. The majority of patients (9 of 11) were asymptomatic. The mean age was 10.8 years (range 6 to 12). Ten of 11 patients had left-sided varicoceles. All varicoceles were grade III except for one that was grade II. Four patients underwent varicocele ligation, 3 via the Ivanessevich approach and 1 via the Palomo approach.

RESULTS

The 4 patients who underwent varicocele ligation (operative group) had a follow-up that ranged from 6 to 72 months (mean 27.2) and the 7 patients who were observed (nonoperative group) had follow-up that ranged from 17 to 84 months (mean 40.8). All patients in the operative group exhibited "catch-up" growth of the affected testicle (mean relative testicular size 47% to 84% at follow-up). The relative left testicular size in the nonoperative group had decreased by a mean of 16.8% from the time of presentation (100% to 83.2% on follow-up).

CONCLUSIONS

We conclude that prepubertal boys should be screened in the standing position for the presence of varicoceles. Secondary causes should be excluded. Patients may ultimately require intervention as our initial experience suggests improved testicular growth with early surgical repair.

Contralateral reflux after unilateral ureteral reimplantation in patients with a history of resolved contralateral reflux

PURPOSE

We determined the risk of contralateral reflux after unilateral ureteral reimplantation in patients with a history of resolved contralateral reflux.

MATERIALS AND METHODS

We reviewed our experience with 53 children who underwent unilateral ureteral reimplantation for primary vesicoureteral reflux.

RESULTS

Postoperative contralateral reflux occurred in 5 of 11 children (45%) with a history of bilateral reflux that had resolved preoperatively on the contralateral side and 4 of 42 (10%) with no history of contralateral reflux.

CONCLUSIONS

Strong consideration should be given to performing bilateral ureteral reimplantation in children with unilateral reflux and a history of resolved contralateral reflux.

Ureterocalycostomy

Ureterocalycostomy, although infrequently indicated, can be a most useful aid to the urologist who is facing a difficult reconstruction problem. The use of this technique to provide internal urinary drainage in 2 patients with long-term nephrostomy tube drainage is described. One patient had a solitary functioning kidney. A third patient, facing nephrectomy from blunt renal trauma, had the kidney saved by this procedure. The technique of ureterocalycostomy is discussed.

Reflux in complete duplication in children

Reflux is the most common abnormality associated with complete ureteral duplication. Several authors have emphasized early surgical correction of reflux when it occurs in duplicated systems. because of a negligible success rate in non-operative therapy. Our practice has been to judge an orifice with reflux on its own merit, that is position, appearance and submucosal tunnel length. Realizing that this philosophy is not in total agreement with most of the literature on reflux in ureteral duplication we have reviewed 59 cases to ascertain whether our non-operative approach has justification. In this study early operation was elected in 61 per cent of those patients with reflux in association with total duplication. However, in 48 per cent of patients followed with non-operative surveillance reflux has either stopped spontaneously or is medically stable.