An ingredient for the elixir of youth

GDF11 level and its effect on prognosis in patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the proliferation of CD34 positive self-renewing malignant hematopoietic stem cells. Previous studies have shown that the transforming growth factor beta (TGFβ) pathway plays a role in AML pathogenesis, especially by affecting the microenvironment. Growth differentiation factor 11 (GDF11) is a member of the TGFβ superfamily, involved in embryological development and known as rejuvenating factor. In this study, our aim was to determine the serum GDF11 level in patients with AML, to compare it with the control group, to determine its relationship with follistatin, vimentin, and E-cadherin levels, and to determine whether GDF11 influences AML prognosis. Serum GDF11, vimentin, follistatin, and E-cadherin levels of newly diagnosed or relapsed/refractory AML patients and age- and gender-matched control group were measured by enzyme-linked immunosorbent assay. Serum GDF11 level was higher in the patient group (263.87 ± 126.54 ng/L) compared to the control group (211.54 ± 61.47 ng/L; p = 0.035). GDF11 level did not change according to age, gender, hemoglobin level, and bone marrow blast rate. No correlation was found between GDF11 level, response rates, and survival status of the patients. A positive correlation was detected between GDF11, E-cadherin, and vimentin levels. As a conclusion, increased serum GDF11 levels in AML patients may be linked to the regeneration ability of leukemic stem cells. There is a need for studies investigating GDF11 expression in myeloblasts.

Dietary intake of GDF11 delays the onset of several biomarkers of aging in male mice through anti-oxidant system via Smad2/3 pathway

Current studies have generated controversy over the age-related change in concentration of growth differentiation factor 11 (GDF11) and its role in the genesis of rejuvenation conditions. In this study, we displayed rGDF11 on the surface of Yarrowic Lipolytica (Y. lipolytica), and proved the bioavailability of the yeast-displayed rGDF11 by oral delivery in aged male mice. On the basis of these findings, we started to explore the anti-aging activity and underlying mechanisms of displayed rGDF11. It was found that dietary intake of displayed rGDF11 had little influence on the body weight and biochemical parameters of aged male mice, but delayed the occurrence and development of age-related biomarkers such as lipofuscin (LF) and senescence-associated-β-galactosidase, and to some extent, prolonged the lifespan of aged male mice. Moreover, we demonstrated once again that dietary intake of displayed rGDF11 enhanced the activity of anti-oxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX), reduced the reactive oxygen species (ROS) level, and slowed down the protein oxidation and lipid peroxidation. Importantly, we showed for the first time that rGDF11 enhanced the activity of CAT, SOD and GPX through activation of the Smad2/3 signaling pathway. Our study also provided a simple and safe route for delivery of recombinant GDF11, facilitating its therapeutic application in the future.

Gonadal rejuvenation of mice by GDF11

Growth differentiation factor 11 (GDF11), also known as bone morphogenetic protein 11 (BMP11), has been shown to have rejuvenation and anti-aging properties, but little information is available regarding the role of GDF11 in reproductive system to date. In this study, we first confirmed the bioavailability of recombinant GDF11 (rGDF11) by oral delivery in mice. We also showed that dietary intake of rGDF11 had little influence on body and gonadal (ovary/testis) weights of recipient mice, indicating their general condition and physiology were not affected. Based on these findings, we started to test the function of rGDF11 in ovary and testis of mice and to explore the underlying mechanisms. It was found that to some extent, rGDF11 could attenuate the senescence of ovarian and testicular cells, and contribute to the recovery of ovarian and testicular endocrine functions. Moreover, rGDF11 could rescue the diminished ovarian reserve in female mice and enhance the activities of marker enzymes of testicular function (SDH and G6PD) in male mice, suggesting a potential improvement of fertility. Notably, rGDF11 markedly promoted the activities of antioxidant enzymes in the ovary and testis, and remarkably reduced the levels of lipid peroxidation, protein oxidation and ROS in the ovary and testis. Collectively, these results suggest that GDF11 can protect ovarian and testicular functions of aged mice via slowing down the generation of ROS through enhancing activities of antioxidant enzymes.

GDF11 alleviates secondary brain injury after intracerebral hemorrhage via attenuating mitochondrial dynamic abnormality and dysfunction

Intracerebral hemorrhage (ICH) is a serious public health problem with high rates of death and disability. The neuroprotective effect of Growth Differentiation Factor 11 (GDF11) in ICH has been initially proved by our previous study. Oxidative stress (OS) plays crucial roles in mediating subsequent damage of ICH. However, whether and how mitochondrial dynamic events and function participated in ICH pathophysiology, and how mitochondrial function and OS interreacted in the neuroprotective process of GDF11 in ICH remains unclarified. Based on the rat model of ICH and in vitro cell model, we demonstrated that GDF11 could alleviate ICH induced neurological deficits, brain edema, OS status, neuronal apoptosis and inflammatory reaction. In addition, mitochondrial functional and structural impairments were obviously restored by GDF11. Treatment with antioxidant protected against erythrocyte homogenate (EH) induced cell injury by restoring OS status and mitochondrial fusion fission imbalance, which was similar to the effect of GDF11 treatment. Further, inhibition of mitochondrial division with Mdivi-1 attenuated mitochondrial functional defects and neuronal damages. In conclusion, our results for the first time proposed that GDF11 protected the post-ICH secondary injury by suppressing the feedback loop between mitochondrial ROS production and mitochondrial dynamic alteration, resulting in attenuated mitochondrial function and amelioration of neural damage.

Safety and efficacy of amniotic cytokine extract in the treatment of dry eye disease

Purpose: Evaluate the safety and efficacy of cryopreserved amniotic cytokine extract (ACE) in the treatment of subjects with dry eye disease (DED). Patients and methods: This was a retrospective, multicenter, chart review of adult patients with DED that instilled cryopreserved ACE drops twice-daily for 4 or 12 weeks. Patients had corneal fluorescein staining (0-20 range) and/or a lissamine green conjunctival staining score (0-18 range) of ≥3 and ≤9 in at least 1 eye and a score ≥40 (0-100 range) of eye dryness/irritation on a visual analog scale (VAS). Following completion of a treatment course, medical records were reviewed from the initiation of therapy (baseline), and at post-treatment visits (4 weeks, 8 weeks, and 12 weeks). Patient records for visual acuity, adverse events, corneal fluorescein staining, conjunctival lissamine green staining, and symptom scores of ocular dryness/irritation were reviewed for each visit, as available. Safety and tolerability were assessed through the evaluation of patient-reported adverse events recorded in the medical records. Results: A total of 54 eligible patients were identified at 7 clinical sites; 16 patients administered ACE drops for 4-weeks, and 38 patients instilled ACE drops for 12 weeks. Significant improvements in the mean changes from baseline were observed for corneal fluorescein staining, lissamine green staining, visual acuity (LogMar) and VAS ocular symptom scores at the 4-week post-treatment visit (p<0.01). Additional improvements continued out to the 12-week follow-up assessment visits. Two patients discontinued therapy due to reports of ocular burning or foreign body sensation. Conclusion: The cryopreserved ACE formulation was well-tolerated and effective in reducing the clinical signs and symptoms of DED. Conduct of a vehicle-controlled prospective study is warranted.

Neuroprotective potential of GDF11 in experimental intracerebral hemorrhage in elderly rats

The occurrence of intracerebral hemorrhage (ICH) costs long-standing neurologic deficits in ICH survivors, elderly ones in particular. Recent researches have proved rejuvenating effect of Growth Differentiation Factor 11 (GDF11) in improving multiple systemic diseases on old individuals. Thus, we designed this study to explore the neuroprotective effect and mechanisms of GDF11 in elderly ICH. 45 aged male Sprague-Dawley (SD) rats were randomly divided into sham + vehicle, ICH + vehicle and ICH + rGDF11 groups. ICH models were induced via injection of autologous whole blood into right basal ganglia of rats. ICH rats were given a daily injection of either recombinant (r) GDF11 at 0.1 mg/kg or vehicle for 28 days prior to operation and continued till the experiment completed. Neurological deficits, brain edema, cell apoptosis, microglial activation and heme oxygenase-1 (HO-1) positive cells were compared among each group. In addition, cytochrome c release, mitochondrial calcium buffering capacity and ATP level were monitored to explore the level of mitochondrial injury. Seen in the result, behavior disorders, severe perihematomal edema, inflammation, apoptosis, oxidative stress and mitochondria damage indicated a significant increase in ICH + vehicle group. While in ICH + rGDF11 group, administration of rGDF11 successfully reduced neurological deficits and alleviated ICH-induced edema, inflammation, apoptosis, oxidative stress, and mitochondria damage in perihematomal tissues. Collectively, our study showed that GDF11 ameliorated ICH-induced neurological deficits in elderly individuals via reducing perihematomal edema, apoptosis, inflammatory reaction, oxidative stress and improving mitochondrial dysfunction, indicating neuroprotective effect of GDF11 in elderly ICH.

Administration of rGDF11 retards the aging process in male mice via action of anti-oxidant system

One of the most studied and widely accepted conjectures of aging process is the oxidative stress theory. Current studies have generated disputes on the effects of GDF11 and GDF8, a closely related member of GDF11, on rejuvenation and anti-aging properties. In this study, we first demonstrated that when recombinant GDF8 (rGDF8) and GDF11 (rGDF11) of the fish Nothobranchius guentheri were injected into 20-month-old male mice, their serum GDF8 and GDF11 levels were clearly increased. We also showed that injection of rGDF8 and rGDF11 had little influences on the body weight and serological parameters of the mice, indicating their general condition and physiology were not affected. Based on these findings, we started to test the effects of administration of piscine rGDF11 and rGDF8 on the aging process of male mice and to explore the underlying mechanisms. It was found that rGDF11 was able to reduce the levels of AGEs, protein oxidation and lipid peroxidation, and to slow down the accumulation of age-related histological markers, while rGDF8 was not. Moreover, rGDF11 significantly prevented the decrease in CAT, GPX and SOD activities, but rGDF8 did not. Collectively, these results suggest that it is GDF11 but not GDF8 that can exert rejuvenation and anti-aging activities via the action of antioxidant system. It is also the first report that shows the activity of GDF11 is not species-specific, implicating potential usefulness of piscine GDF11 in prolonging the lifespan of the elderly.

Role of growth differentiation factor 11 in development, physiology and disease

Growth differentiation factor (GDF11) is a member of TGF-β/BMP superfamily that activates Smad and non-Smad signaling pathways and regulates expression of its target nuclear genes. Since its discovery in 1999, studies have shown the involvement of GDF11 in normal physiological processes, such as embryonic development and erythropoiesis, as well as in the pathophysiology of aging, cardiovascular disease, diabetes mellitus, and cancer. In addition, there are contradictory reports regarding the role of GDF11 in aging, cardiovascular disease, diabetes mellitus, osteogenesis, skeletal muscle development, and neurogenesis. In this review, we describe the GDF11 signaling pathway and its potential role in development, physiology and disease.

Modulation of GDF11 expression and synaptic plasticity by age and training

The Growth Differentiation Factor 11 (GDF11) has been controversially involved in the aging/rejuvenation process. To clarify whether GDF11 is differently expressed during aging, we have evaluated GDF11 levels in skeletal muscles and hippocampi of young and old mice, sedentary or subjected to a 12-weeks triweekly training protocol. The results of real-time PCR and Western blot analyses indicate that skeletal muscles of sedentary old mice express higher levels of GDF11 compared to young animals (p < 0.05). Conversely, in hippocampi no significant differences of GDF11 expression are detected. Analysis of long-term potentiation, a synaptic plasticity phenomenon, reveals that population spikes in response to a tetanic stimulus are significantly higher in sedentary young mice than in old animals (p < 0.01). Training induces a significant improvement of long-term potentiation in both young and old animals (p < 0.05), an increase (p < 0.05) of skeletal muscle GDF11 levels in young mice and a reduction of GDF11 expression in hippocampi of old mice (p < 0.05). Overall, data suggest that GDF11 can be considered an aging biomarker for skeletal muscles. Moreover, physical exercise has a positive impact on long-term potentiation in both young and old mice, while it has variable effects on GDF11 expression depending on age and on the tissue analyzed.

Exogenous GDF11 induces cardiac and skeletal muscle dysfunction and wasting

Growth differentiation factor 11 (GDF11), a TGF-beta superfamily member, is highly homologous to myostatin and essential for embryonic patterning and organogenesis. Reports of GDF11 effects on adult tissues are conflicting, with some describing anti-aging and pro-regenerative activities on the heart and skeletal muscle while others opposite or no effects. Herein, we sought to determine the in vivo cardiac and skeletal muscle effects of excess GDF11. Mice were injected with GDF11 secreting cells, an identical model to that used to initially identify the in vivo effects of myostatin. GDF11 exposure in mice induced whole body wasting and profound loss of function in cardiac and skeletal muscle over a 14-day period. Loss of cardiac mass preceded skeletal muscle loss. Cardiac histologic and echocardiographic evaluation demonstrated loss of ventricular muscle wall thickness, decreased cardiomyocyte size, and decreased cardiac function 10 days following initiation of GDF11 exposure. Changes in skeletal muscle after GDF11 exposure were manifest at day 13 and were associated with wasting, decreased fiber size, and reduced strength. Changes in cardiomyocytes and skeletal muscle fibers were associated with activation of SMAD2, the ubiquitin-proteasome pathway and autophagy. Thus, GDF11 over administration in vivo results in cardiac and skeletal muscle loss, dysfunction, and death. Here, serum levels of GDF11 by Western blotting were 1.5-fold increased over controls. Although GDF11 effects in vivo are likely dose, route, and duration dependent, its physiologic changes are similar to myostatin and other Activin receptors ligands. These data support that GDF11, like its other closely related TGF-beta family members, induces loss of cardiac and skeletal muscle mass and function.

β-thalassemias: paradigmatic diseases for scientific discoveries and development of innovative therapies

β-thalassemias are monogenic disorders characterized by defective synthesis of the β-globin chain, one of the major components of adult hemoglobin. A large number of mutations in the β-globin gene or its regulatory elements have been associated with β-thalassemias. Due to the complexity of the regulation of the β-globin gene and the role of red cells in many physiological processes, patients can manifest a large spectrum of phenotypes, and clinical requirements vary from patient to patient. It is important to consider the major differences in the light of potential novel therapeutics. This review summarizes the main discoveries and mechanisms associated with the synthesis of β-globin and abnormal erythropoiesis, as well as current and novel therapies.

Fabrication of polymeric biomaterials: a strategy for tissue engineering and medical devices

Fabrication of biomaterials scaffolds using various methods and techniques is discussed, utilising biocompatible, biodegradable and stimuli-responsive polymers and their composites. This review covers the lithography and printing techniques, self-organisation and self-assembly methods for 3D structural scaffolds generation, and smart hydrogels, for tissue regeneration and medical devices.