Chronic treatment with the mitochondrial peptide humanin prevents age-related myocardial fibrosis in mice.

Cardiac fibrosis is a biological process that increases with age and contributes to myocardial dysfunction. Humanin (HN) is an endogenous mitochondria-derived peptide that has cytoprotective effects and reduces oxidative stress. The present study aimed to test the hypothesis that chronic supplementation of exogenous HN in middle-aged mice could prevent and reverse cardiac fibrosis and apoptosis in the aging heart. Female C57BL/6N mice at 18 mo of age received 14-mo intraperitoneal injections of vehicle (old group; n = 6) or HN analog (HNG; 4 mg/kg 2 times/wk, old + HNG group, n = 8) and were euthanized at 32 mo of age. C57BL/6N female mice (young group, n = 5) at 5 mo of age were used as young controls. HNG treatment significantly increased the ratio of cardiomyocytes to fibroblasts in aging hearts, as shown by the percentage of each cell type in randomly chosen fields after immunofluorescence staining. Furthermore, the increased collagen deposition in aged hearts was significantly reduced after HNG treatment, as indicated by picrosirius red staining. HNG treatment also reduced in aging mice cardiac fibroblast proliferation (5'-bromo-2-deoxyuridine staining) and attenuated transforming growth factor-ß1, fibroblast growth factor-2, and matrix metalloproteinase-2 expression (immunohistochemistry or real-time PCR). Myocardial apoptosis was inhibited in HNG-treated aged mice (TUNEL staining). To decipher the pathway involved in the attenuation of the myocardial fibrosis by HNG, Western blot analysis was done and showed that HNG upregulated the Akt/glycogen synthase kinase -3ß pathway in aged mice. Exogenous HNG treatment attenuated myocardial fibrosis and apoptosis in aged mice. The results of the present study suggest a role for the mitochondria-derived peptide HN in the cardioprotection associated with aging. NEW & NOTEWORTHY Cardiac fibrosis is a biological process that increases with age and contributes to myocardial dysfunction. Humanin is an endogenous mitochondria-derived peptide that has cytoprotective effects and reduces oxidative stress. Here, we demonstrate, for the first time, that exogenous humanin treatment attenuated myocardial fibrosis and apoptosis in aging mice. We also detected upregulated Akt/glycogen synthase kinase-3ß pathway in humanin analog-treated mice, which might be the mechanism involved in the cardioprotective effect of humanin analog in aging mice.

Bowel habits and fecal incontinence in patients with obesity undergoing evaluation for weight loss: the importance of stool consistency.

BACKGROUND: Fecal incontinence is highly prevalent in the general population and especially in risk groups. Obesity is also common and is associated with comorbidities that impair general health and interfere with daily activities. Identifying mutable factors for fecal incontinence, such as stool consistency, is of paramount importance to improve quality of life. OBJECTIVE: The aim of this study was to estimate the prevalence of fecal incontinence in patients with obesity undergoing evaluation for weight loss, its relationship with bowel habits, and its impact on quality of life. DESIGN: This investigation is a cross-sectional observational study. SETTINGS: This study was conducted in patients with obesity who were undergoing evaluation for weight loss. MAIN OUTCOME MEASURES: Fecal incontinence was defined as loss of flatus or liquid/solid stool occurring at least monthly. Data on comorbidities, BMI, quality of life, bowel habits including stool consistency measured with the Bristol Stool Form Scale, and symptoms of fecal incontinence were collected. RESULTS: Fifty-two patients were included, with a mean BMI of 39.6 kg/m2. Symptoms of fecal incontinence were found in 17 patients (32.7%): flatus in 9 of 17 (52.9%), liquid stool in 6 of 17 (35.2%), and solid stool in 2 of 17 (11.7%). No differences were found between patients with and without fecal incontinence in age, sex, comorbidities, or BMI. Health-related quality of life was lower in patients with fecal incontinence than in those without, but this difference was not significant, with the exception of the dimensions of role-physical (p = 0.03) and social functioning (p = 0.04). Patients with incontinence reported significantly higher percentages of altered bowel habits with nonformed stools (p = 0.004). LIMITATIONS: The cross-sectional design hampered identification of the time at which the impact of obesity occurred. CONCLUSIONS: Fecal incontinence is common in patients with obesity. Stool consistency was significantly different in these patients. This study supports the possibility of improving incontinence during weight loss by modifying stool consistency.

Fasting-mimicking diet prevents high-fat diet effect on cardiometabolic risk and lifespan.

Diet-induced obesity is a major risk factor for metabolic syndrome, diabetes and cardiovascular disease. Here, we show that a 5-d fasting-mimicking diet (FMD), administered every 4 weeks for a period of 2 years, ameliorates the detrimental changes caused by consumption of a high-fat, high-calorie diet (HFCD) in female mice. We demonstrate that monthly FMD cycles inhibit HFCD-mediated obesity by reducing the accumulation of visceral and subcutaneous fat without causing loss of lean body mass. FMD cycles increase cardiac vascularity and function and resistance to cardiotoxins, prevent HFCD-dependent hyperglycaemia, hypercholesterolaemia and hyperleptinaemia and ameliorate impaired glucose and insulin tolerance. The effect of monthly FMD cycles on gene expression associated with mitochondrial metabolism and biogenesis in adipocytes and the sustained ketogenesis in HFCD-fed mice indicate a role for fat cell reprogramming in obesity prevention. These effects of an FMD on adiposity and cardiac ageing could explain the protection from HFCD-dependent early mortality.

The mitochondrial derived peptide humanin is a regulator of lifespan and healthspan.

Humanin is a member of a new family of peptides that are encoded by short open reading frames within the mitochondrial genome. It is conserved in animals and is both neuroprotective and cytoprotective. Here we report that in C. elegans the overexpression of humanin is sufficient to increase lifespan, dependent on daf-16/Foxo. Humanin transgenic mice have many phenotypes that overlap with the worm phenotypes and, similar to exogenous humanin treatment, have increased protection against toxic insults. Treating middle-aged mice twice weekly with the potent humanin analogue HNG, humanin improves metabolic healthspan parameters and reduces inflammatory markers. In multiple species, humanin levels generally decline with age, but here we show that levels are surprisingly stable in the naked mole-rat, a model of negligible senescence. Furthermore, in children of centenarians, who are more likely to become centenarians themselves, circulating humanin levels are much greater than age-matched control subjects. Further linking humanin to healthspan, we observe that humanin levels are decreased in human diseases such as Alzheimer's disease and MELAS (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes). Together, these studies are the first to demonstrate that humanin is linked to improved healthspan and increased lifespan.

Fasting-Mimicking Diet Modulates Microbiota and Promotes Intestinal Regeneration to Reduce Inflammatory Bowel Disease Pathology.

Dietary interventions are potentially effective therapies for inflammatory bowel diseases (IBDs). We tested the effect of 4-day fasting-mimicking diet (FMD) cycles on a chronic dextran sodium sulfate (DSS)-induced murine model resulting in symptoms and pathology associated with IBD. These FMD cycles reduced intestinal inflammation, increased stem cell number, stimulated protective gut microbiota, and reversed intestinal pathology caused by DSS, whereas water-only fasting increased regenerative and reduced inflammatory markers without reversing pathology. Transplants of Lactobacillus or fecal microbiota from DSS- and FMD-treated mice reversed DSS-induced colon shortening, reduced inflammation, and increased colonic stem cells. In a clinical trial, three FMD cycles reduced markers associated with systemic inflammation. The effect of FMD cycles on microbiota composition, immune cell profile, intestinal stem cell levels and the reversal of pathology associated with IBD in mice, and the anti-inflammatory effects demonstrated in a clinical trial show promise for FMD cycles to ameliorate IBD-associated inflammation in humans.

Humanin Prevents Age-Related Cognitive Decline in Mice and is Associated with Improved Cognitive Age in Humans.

Advanced age is associated with a decline in cognitive function, likely caused by a combination of modifiable and non-modifiable factors such as genetics and lifestyle choices. Mounting evidence suggests that humanin and other mitochondrial derived peptides play a role in several age-related conditions including neurodegenerative disease. Here we demonstrate that humanin administration has neuroprotective effects in vitro in human cell culture models and is sufficient to improve cognition in vivo in aged mice. Furthermore, in a human cohort, using mitochondrial GWAS, we identified a specific SNP (rs2854128) in the humanin-coding region of the mitochondrial genome that is associated with a decrease in circulating humanin levels. In a large, independent cohort, consisting of a nationally-representative sample of older adults, we find that this SNP is associated with accelerated cognitive aging, supporting the concept that humanin is an important factor in cognitive aging.

Effects of Prolonged GRP78 Haploinsufficiency on Organ Homeostasis, Behavior, Cancer and Chemotoxic Resistance in Aged Mice.

GRP78, a multifunctional protein with potent cytoprotective properties, is an emerging therapeutic target to combat cancer development, progression and drug resistance. The biological consequences of prolonged reduction in expression of this essential chaperone which so far has been studied primarily in young mice, was investigated in older mice, as older individuals are likely to be important recipients of anti-GRP78 therapy. We followed cohorts of Grp78+/+ and Grp78+/- male and female mice up to 2 years of age in three different genetic backgrounds and characterized them with respect to body weight, organ integrity, behavioral and memory performance, cancer, inflammation and chemotoxic response. Our results reveal that body weight, organ development and integrity were not impaired in aged Grp78+/- mice. No significant effect on cancer incidence and inflammation was observed in aging mice. Interestingly, our studies detected some subtle differential trends between the WT and Grp78+/- mice in some test parameters dependent on gender and genetic background. Our studies provide the first evidence that GRP78 haploinsufficiency for up to 2 years of age has no major deleterious effect in rodents of different genetic background, supporting the merit of anti-GRP78 drugs in treatment of cancer and other diseases affecting the elderly.

Detection of ketonemia and its relationship with hyperglycemia in type 1 diabetic patients.

The aims of this study were to assess the prevalence of ketosis in type 1 diabetic patients with casual hyperglycemia (>250 mg/dl), to establish the relationship between glycemia and ketonemia during daily life, and to determine the utility of ketonemia. Capillary glycemia levels from 562 type 1 diabetic patients were recorded. Prevalence of casual hyperglycemia was 27.58%, and prevalence of asymptomatic ketonemia was 8.39%. Regarding blood ketone levels, 110 out of 155 patients (70.96%) had blood ketone levels of between 0 and 0.1 mmol/l and 32 out of 155 patients (20.63%) had blood ketone levels of between 0.2 and 0.4 mmol/l. Surprisingly, the mean glycemia levels in these subgroups did not differ and was consistently high (around 300 mg/dl), leading to the observation that even ketone levels considered as non-pathologic should probably be taken into account for a proper diabetes control. Some discrepancies between quantitative determination of ketonuria and qualitative determination of ketonemia were observed. That is in 20 patients with positive ketonuria, ketonemia was not detected, probably because ketosis was already resolved. Asymptomatic ketosis was observed in the hyperglycemic type 1 diabetic population, and metabolic control of these patients with a point of care device is recommended, together with a subsequent revision of insulin treatment. Furthermore, this study supports the opinion that the presence of ketosis, detected by beta-OHB levels, even below levels considered as pathologic, together with hyperglycemia, must be taken into account for proper monitoring and therapeutic control of diabetic patients.

A Periodic Diet that Mimics Fasting Promotes Multi-System Regeneration, Enhanced Cognitive Performance, and Healthspan.

Prolonged fasting (PF) promotes stress resistance, but its effects on longevity are poorly understood. We show that alternating PF and nutrient-rich medium extended yeast lifespan independently of established pro-longevity genes. In mice, 4 days of a diet that mimics fasting (FMD), developed to minimize the burden of PF, decreased the size of multiple organs/systems, an effect followed upon re-feeding by an elevated number of progenitor and stem cells and regeneration. Bi-monthly FMD cycles started at middle age extended longevity, lowered visceral fat, reduced cancer incidence and skin lesions, rejuvenated the immune system, and retarded bone mineral density loss. In old mice, FMD cycles promoted hippocampal neurogenesis, lowered IGF-1 levels and PKA activity, elevated NeuroD1, and improved cognitive performance. In a pilot clinical trial, three FMD cycles decreased risk factors/biomarkers for aging, diabetes, cardiovascular disease, and cancer without major adverse effects, providing support for the use of FMDs to promote healthspan.