The brain, sirtuins, and ageing.

In mammals, recent studies have demonstrated that the brain, the hypothalamus in particular, is a key bidirectional integrator of humoral and neural information from peripheral tissues, thus influencing ageing both in the brain and at the 'systemic' level. CNS decline drives the progressive impairment of cognitive, social and physical abilities, and the mechanisms underlying CNS regulation of the ageing process, such as microglia-neuron networks and the activities of sirtuins, a class of NAD+-dependent deacylases, are beginning to be understood. Such mechanisms are potential targets for the prevention or treatment of age-associated dysfunction and for the extension of a healthy lifespan.

Experience using mTOR inhibitors for subependymal giant cell astrocytoma in tuberous sclerosis complex at a single facility.

BACKGROUND: Subependymal giant cell astrocytoma (SEGA) is occasionally seen in tuberous sclerosis complex (TSC). Two main options are currently available for treating SEGA: surgical resection or pharmacotherapy using mammalian target of rapamycin inhibitors (mTORi). We hypothesized that opportunities for surgical resection of SEGA would have reduced with the advent of mTORi. METHODS: We retrospectively reviewed the charts of patients treated between August 1979 and July 2020, divided into a pre-mTORi era group (Pre-group) of patients treated before November 2012, and a post-mTORi era group (Post-group) comprising patients treated from November 2012, when mTORi became available in Japan for SEGA. We compared groups in terms of treatment with surgery or mTORi. We also reviewed SEGA size, rate of acute hydrocephalus, recurrence of SEGA, malignant transformation and adverse effects of mTORi. RESULTS: In total, 120 patients with TSC visited our facility, including 24 patients with SEGA. Surgical resection was significantly more frequent in the Pre-group (6 of 7 patients, 86 %) than in the Post-group (2 of 17 patients, 12 %; p = 0.001). Acute hydrocephalus was seen in 1 patient (4 %), and no patients showed malignant transformation of SEGA. The group treated using mTORi showed significantly smaller SEGA compared with the group treated under a wait-and-see policy (p = 0.012). Adverse effects of pharmacotherapy were identified in seven (64 %; 6 oral ulcers, 1 irregular menstruation) of the 11 patients receiving mTORi. CONCLUSIONS: The Post-group underwent surgery significantly less often than the Pre-group. Since the treatment option to use mTORi in the treatment of SEGA in TSC became available, opportunities for surgical resection have decreased in our facility.

Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men.

Recent studies have revealed that decline in cellular nicotinamide adenine dinucleotide (NAD+) levels causes aging-related disorders and therapeutic approaches increasing cellular NAD+ prevent these disorders in animal models. The administration of nicotinamide mononucleotide (NMN) has been shown to mitigate aging-related dysfunctions. However, the safety of NMN in humans have remained unclear. We, therefore, conducted a clinical trial to investigate the safety of single NMN administration in 10 healthy men. A single-arm non-randomized intervention was conducted by single oral administration of 100, 250, and 500 mg NMN. Clinical findings and parameters, and the pharmacokinetics of NMN metabolites were investigated for 5 h after each intervention. Ophthalmic examination and sleep quality assessment were also conducted before and after the intervention. The single oral administrations of NMN did not cause any significant clinical symptoms or changes in heart rate, blood pressure, oxygen saturation, and body temperature. Laboratory analysis results did not show significant changes, except for increases in serum bilirubin levels and decreases in serum creatinine, chloride, and blood glucose levels within the normal ranges, independent of the dose of NMN. Results of ophthalmic examination and sleep quality score showed no differences before and after the intervention. Plasma concentrations of N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-5-carboxamide were significantly increased dose-dependently by NMN administration. The single oral administration of NMN was safe and effectively metabolized in healthy men without causing any significant deleterious effects. Thus, the oral administration of NMN was found to be feasible, implicating a potential therapeutic strategy to mitigate aging-related disorders in humans.

Mitochondrial SIRT3: a new potential therapeutic target for metabolic syndrome.

In this issue of Molecular Cell, Hirschey et al. demonstrate that loss of the NAD(+)-dependent deacetylase SIRT3 and resultant mitochondrial protein hyperacetylation play a critical role in the pathogenesis of metabolic syndrome, providing new insights into the therapeutic potential of SIRT3.

Specific ablation of Nampt in adult neural stem cells recapitulates their functional defects during aging.

Neural stem/progenitor cell (NSPC) proliferation and self-renewal, as well as insult-induced differentiation, decrease markedly with age. The molecular mechanisms responsible for these declines remain unclear. Here, we show that levels of NAD(+) and nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme in mammalian NAD(+) biosynthesis, decrease with age in the hippocampus. Ablation of Nampt in adult NSPCs reduced their pool and proliferation in vivo. The decrease in the NSPC pool during aging can be rescued by enhancing hippocampal NAD(+) levels. Nampt is the main source of NSPC NAD(+) levels and required for G1/S progression of the NSPC cell cycle. Nampt is also critical in oligodendrocytic lineage fate decisions through a mechanism mediated redundantly by Sirt1 and Sirt2. Ablation of Nampt in the adult NSPCs in vivo reduced NSPC-mediated oligodendrogenesis upon insult. These phenotypes recapitulate defects in NSPCs during aging, giving rise to the possibility that Nampt-mediated NAD(+) biosynthesis is a mediator of age-associated functional declines in NSPCs.

Cilostazol inhibits interleukin-1-induced ADAM17 expression through cAMP independent signaling in vascular smooth muscle cells.

Increased A disintegrin and metalloprotease 17 (ADAM17) expression in vascular smooth muscle cells (VSMC) is implicated in the development of cardiovascular diseases including atherosclerosis and hypertension. Although cilostazol, type III phosphodiesterase (PDE III) inhibitor, has recently been found to inhibit VSMC proliferation, the mechanisms remain largely unclear. Here, we hypothesized that cilostazol regulates the ADAM17 expression in VSMC. In cultured VSMC, interleukin (IL)-1α and IL-1ß significantly increased ADAM17 expression. MEK inhibitor U0126, NF-κB inhibitor BAY-11-7085, and siRNA targeting p65/RelA significantly inhibited IL-1α or IL-ß-induced ADAM17 expression. Cilostazol significantly inhibited IL-1α or IL-1ß-induced extracellular signal-regulated kinase (ERK) phosphorylation and ADAM17 expression. Unexpectedly, cilostamide, dibutryl cAMP, and forskolin did not affect IL-1-induced ADAM17 expression. Our results clearly demonstrated that IL-1 induces ADAM17 expression through ERK/NF-κB activation in VSMCs. Moreover, the inhibitory effects of cilostazol on IL-1-induced ADAM17 expression may be independent of the cAMP signaling pathway in VSMC. These novel findings may provide important clues to understanding the expression mechanisms of ADAM17 and the inhibitory mechanisms of cilostazol in VSMC proliferation.

A CASE REPORT OF PANCREATIC METASTASIS FROM PROSTATE CANCER.

We report a case of pancreatic metastasis from prostate cancer. A 65 year-old man developed gross hematuria, and was found to have a markedly elevated PSA and abnormal CT findings indicating mass lesions in bilateral lungs, and pancreatic head, and osteoblastic lesions in pelvic bone. He was referred to the department of Urology and Gastroenterology at Seirei Hamamatsu General Hospital. Digital rectal examination revealed a hen's egg-sized, stony-hard prostate. A systematic needle biopsy of the prostate demonstrated adenocarcinoma (Gleason score 4+4=8). We diagnosed multiple lung and bone metastases from prostate cancer, and suspected that a primary pancreatic ductal carcinoma. The patient was started on an androgen deprivation therapy (ADT) with bicalutamide and degarelix. After 4 months from the initiation of ADT, an MRI of the pancreas showed decreased size of the pancreatic head mass from 18 mm to 7 mm in diameter. We concluded that the pancreatic head mass was metastasis from prostate cancer, and currently continue ADT. Pancreatic metastasis from prostate cancer is very rare, and further accumulation of cases will be required.

Expression of Nampt in hippocampal and cortical excitatory neurons is critical for cognitive function.

Nicotinamide adenine dinucleotide (NAD(+)) is an enzyme cofactor or cosubstrate in many essential biological pathways. To date, the primary source of neuronal NAD(+) has been unclear. NAD(+) can be synthesized from several different precursors, among which nicotinamide is the substrate predominantly used in mammals. The rate-limiting step in the NAD(+) biosynthetic pathway from nicotinamide is performed by nicotinamide phosphoribosyltransferase (Nampt). Here, we tested the hypothesis that neurons use intracellular Nampt-mediated NAD(+) biosynthesis by generating and evaluating mice lacking Nampt in forebrain excitatory neurons (CaMKIIαNampt(-/-) mice). CaMKIIαNampt(-/-) mice showed hippocampal and cortical atrophy, astrogliosis, microgliosis, and abnormal CA1 dendritic morphology by 2-3 months of age. Importantly, these histological changes occurred with altered intrahippocampal connectivity and abnormal behavior; including hyperactivity, some defects in motor skills, memory impairment, and reduced anxiety, but in the absence of impaired sensory processes or long-term potentiation of the Schaffer collateral pathway. These results clearly demonstrate that forebrain excitatory neurons mainly use intracellular Nampt-mediated NAD(+) biosynthesis to mediate their survival and function. Studying this particular NAD(+) biosynthetic pathway in these neurons provides critical insight into their vulnerability to pathophysiological stimuli and the development of therapeutic and preventive interventions for their preservation.

Significant increase of plasma tetranectin in ovx mice as defined by proteomics analysis.

BACKGROUND: Proteomics is recognized as a useful tool in the dynamic screening of plasma protein expression. This study aimed to identify increased expressions of novel plasma proteins in ovariectomized mice (ovx) using selective reaction monitoring (SRM) validation in combination with electrospray ionized-quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) screening. MATERIALS AND METHODS: Twenty-week-old female C57BL/6 mice were ovariectomized or subjected to surgical exposure of the ovaries alone (sham). Blood plasma protein at 4 weeks after these operations was pooled for the ovx and sham group each and separated on SDS-PAGE, and then digested by peptides, which were first differentially displayed by ESI-Q-TOF-MS analysis. Mass spectra of peptides upregulated more than twofold in ovx compared to sham mice were selected for protein identification by ESI-Q-TOF-MS. The selected peptides were further validated in independent samples by SRM using electrospray ionized-triple quadrupole-linear ion trap mass spectrometry (ESI-QqLIT-MS). Optimum transitions for SRM were manually chosen for their high specificity in identifying peptides derived from the candidate proteins. RESULTS: Differential analysis of peptides revealed 1,108 upregulated peptides in ovx compared with sham control mice. Among the upregulated peptides, 231 nonredundant proteins were identified. Validation analysis for the potential use of these proteins as markers of bone turnover was performed using ESI-QqLIT-MS. The four proteins from the plasma samples, namely mannose-binding lectin-C, major urinary protein 2, type I collagen alpha 2 chain, and tetranectin, were evaluated in a blinded manner. A statistically significant elevation of all four proteins in the plasma of ovx mice was confirmed by SRM. Of the four upregulated plasma proteins, tetranectin increased by almost 50 times in the ovx mice compared with the sham mice. CONCLUSIONS: On the basis of proteomics analysis, this study demonstrated that four plasma proteins were significantly elevated in the ovx mice; of these, tetranectin was markedly upregulated by almost 50 times compared with the sham mice.

DMHPpp1r17 neurons regulate aging and lifespan in mice through hypothalamic-adipose inter-tissue communication.

Recent studies have shown that the hypothalamus functions as a control center of aging in mammals that counteracts age-associated physiological decline through inter-tissue communications. We have identified a key neuronal subpopulation in the dorsomedial hypothalamus (DMH), marked by Ppp1r17 expression (DMHPpp1r17 neurons), that regulates aging and longevity in mice. DMHPpp1r17 neurons regulate physical activity and WAT function, including the secretion of extracellular nicotinamide phosphoribosyltransferase (eNAMPT), through sympathetic nervous stimulation. Within DMHPpp1r17 neurons, the phosphorylation and subsequent nuclear-cytoplasmic translocation of Ppp1r17, regulated by cGMP-dependent protein kinase G (PKG; Prkg1), affect gene expression regulating synaptic function, causing synaptic transmission dysfunction and impaired WAT function. Both DMH-specific Prkg1 knockdown, which suppresses age-associated Ppp1r17 translocation, and the chemogenetic activation of DMHPpp1r17 neurons significantly ameliorate age-associated dysfunction in WAT, increase physical activity, and extend lifespan. Thus, these findings clearly demonstrate the importance of the inter-tissue communication between the hypothalamus and WAT in mammalian aging and longevity control.

Absolute quantification of nicotinamide mononucleotide in biological samples by double isotope-mediated liquid chromatography-tandem mass spectrometry (dimeLC-MS/MS).

Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite for fundamental biological phenomena, including aging. Nicotinamide mononucleotide (NMN) is a key NAD+ intermediate that has been extensively tested as an effective NAD+-boosting compound in mice and humans. However, the accurate measurement of NMN in biological samples has long been a challenge in the field. Here, we have established an accurate, quantitative methodology for measuring NMN by using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) with double isotopic NMN standards. In this new methodology, the matrix effects of biological samples were properly adjusted, and the fate of NMN could be traced during sample processing. We have demonstrated that this methodology can accurately quantitate NMN levels in mouse plasma and confirmed quick, direct NMN uptake into blood circulation and cells. This double isotope-mediated LC-MS/MS (dimeLC-MS/MS) can easily be expanded to other NAD+-related metabolites as a reliable standard methodology for NAD+ biology.

[The sirtuin family : regulators that connect metabolism, aging, and longevity].

Recently, studies on the mechanisms of aging and longevity have been making significant progresses. Through those studies, the SIR2 (silent information regulator 2) family proteins, now called "sirtuins" , have drawn much attention as important regulators that connect metabolism, aging, and longevity. The general feature of sirtuin function is to maintain the robustness of the physiological system in response to or prevent its destruction from various internal and external perturbations. This particular function of sirtuins allows them to play critical roles in the regulation of many biological processes, including the regulation of aging and longevity. In this review article, recent findings in this quickly evolving field of sirtuin biology will be summarized, and the importance of sirtuins on the regulation of aging and longevity will be discussed.

Quantification of localized NAD+ changes reveals unique specificity of NAD+ regulation in the hypothalamus.

Recently, it has become a consensus that systemic decreases in NAD+ are a critical trigger for age-associated functional decline in multiple tissues and organs. The hypothalamus, which contains several functionally distinct subregions called nuclei, functions as a high-order control center of aging in mammals. However, due to a technical difficulty, how NAD+ levels change locally in each hypothalamic nucleus during aging remains uninvestigated. We were able to establish a new combinatorial methodology, using laser-captured microdissection (LCM) and high-performance liquid chromatography (HPLC), to accurately measure NAD+ levels in small tissue samples. We applied this methodology to examine local NAD+ changes in hypothalamic nuclei and found that NAD+ levels were decreased significantly in the arcuate nucleus (ARC), ventromedial hypothalamus (VMH), and lateral hypothalamus (LH), but not in the dorsomedial hypothalamus (DMH) of 22-month-old mice, compared to those of 3-month-old mice. The administration of nicotinamide mononucleotide (NMN) significantly increased NAD+ levels in all these hypothalamic nuclei. Interestingly, the administration of extracellular nicotinamide phosphoribosyltransferase-containing extracellular vesicles (eNampt-EVs) purified from young mice increased NAD+ levels in the ARC and DMH. These results reveal the unique specificity of NAD+ regulation in the hypothalamus during aging.

Aging reduces motivation through decreased Bdnf expression in the ventral tegmental area.

Age-associated reduced motivation is a hallmark of neuropsychiatric disorders in the elderly. In our rapidly aging societies, it is critical to keep motivation levels high enough to promote healthspan and lifespan. However, how motivation is reduced during aging remains unknown. Here, we used multiple mouse models to evaluate motivation and related affective states in young and old mice. We also compared the effect of social isolation, a common stressor, to those of aging. We found that both social isolation and aging decreased motivation in mice, but that Bdnf expression in the ventral tegmental area (VTA) was selectively decreased during aging. Furthermore, VTA-specific Bdnf knockdown in young mice recapitulated reduced motivation observed in old mice. These results demonstrate that maintaining Bdnf expression in the VTA could promote motivation to engage in effortful activities and potentially prevent age-associated neuropsychiatric disorders.

A case of adrenal lymphangioma successfully treated with laparoscopic partial adrenalectomy.

Introduction: Adrenal lymphangioma is a rare benign tumor of lymphatic origin, usually incidentally detected from various imaging studies taken for an unrelated purpose. We present a case of a right adrenal lymphangioma treated successfully with surgical intervention. Case presentation: A 36-year-old previously healthy woman was referred to our urology department for a right adrenal mass, discovered during a routine health checkup. The tumor had no endocrinological activity, and the patient opted for surgical resection following a concern for malignancy. A laparoscopic right partial adrenalectomy was performed, and on histological examination, the tumor was diagnosed as right adrenal lymphangioma. Conclusion: Adrenal lymphangiomas lack disease specific radiological characteristics that allow for a definitive diagnosis from imaging alone. To rule out tumors of potentially malignant nature, surgical intervention should be considered.

A case of prostatic metastasis from non-seminomatous testicular cancer.

Introduction: Prostatic metastasis from testicular cancer is extremely rare, with only 10 reported cases, all of which were diagnosed as relapse. Herein, we report the case of a patient with concurrent testicular cancer and prostatic metastasis. Case presentation: A 57-year-old man presented at our emergency department with urinary retention. A painless mass was found in the right scrotum, and computed tomography showed lung, mediastinal, and liver metastases, and an enlarged prostate. Tumor markers were measured in 2057 U/L lactate dehydrogenase, 2460 mIU/mL human chorionic gonadotrophin, 1303 ng/mL alpha-fetoprotein, and 1.51 ng/mL prostate specific antigen. An orchiectomy and biopsy were performed; the pathological results showed immature teratomas, embryonal carcinomas, choriocarcinomas, and seminomas in the testis, and embryonal carcinomas in the prostate, liver, and mediastinum. The patient refused chemotherapy and died 3 months following diagnosis. Conclusion: Prostatic metastasis should be considered in cases of dysuria or prostate enlargement in testicular cancers.

Effects of nicotinamide mononucleotide on older patients with diabetes and impaired physical performance: A prospective, placebo-controlled, double-blind study.

OBJECTIVE: Nicotinamide adenine dinucleotide regulates various biological processes. Nicotinamide mononucleotide (NMN) increases its intracellular levels and counteracts age-associated changes in animal models. We investigated the safety and efficacy of oral nicotinamide mononucleotide supplementation in older patients with diabetes and impaired physical performance. METHOD: We carried out a 24-week placebo-controlled, double-blinded study of male patients with diabetes aged ≥65 years with reduced grip strength (<26 kg) or walking speed (<1.0 m/s). The primary end-points were to determine the safety of NMN oral administration (250 mg/day), and changes in grip strength and walking speed. The secondary end-points were to determine the changes in various exploratory indicators. RESULTS: We studied 14 participants aged 81.1 ± 6.4 years. NMN was tolerable without any severe adverse events. The changes in grip strength and walking speed showed no difference between the two groups: 1.25 kg (95% confidence interval -2.31 to 4.81) and 0.033 m/s (-0.021 to 0.087) in the NMN group, and -0.44 kg (-4.15 to 3.26) and 0.014 m/s (-0.16 to -0.13) in the placebo group, respectively. There were no significant differences in any exploratory indicators between the two groups. However, improved prevalence of frailty in the NMN group (P = 0.066) and different changes in central retinal thickness between the two groups (P = 0.051) was observed. CONCLUSION: In older male patients with diabetes and impaired physical performance, NMN supplementation for 24 weeks was safe, but did not improve grip strength and walking speed. Geriatr Gerontol Int 2023; 23: 38-43.

Sleep-wake patterns are altered with age, Prdm13 signaling in the DMH, and diet restriction in mice.

Old animals display significant alterations in sleep-wake patterns such as increases in sleep fragmentation and sleep propensity. Here, we demonstrated that PR-domain containing protein 13 (Prdm13)+ neurons in the dorsomedial hypothalamus (DMH) are activated during sleep deprivation (SD) in young mice but not in old mice. Chemogenetic inhibition of Prdm13+ neurons in the DMH in young mice promotes increase in sleep attempts during SD, suggesting its involvement in sleep control. Furthermore, DMH-specific Prdm13-knockout (DMH-Prdm13-KO) mice recapitulated age-associated sleep alterations such as sleep fragmentation and increased sleep attempts during SD. These phenotypes were further exacerbated during aging, with increased adiposity and decreased physical activity, resulting in shortened lifespan. Dietary restriction (DR), a well-known anti-aging intervention in diverse organisms, ameliorated age-associated sleep fragmentation and increased sleep attempts during SD, whereas these effects of DR were abrogated in DMH-Prdm13-KO mice. Moreover, overexpression of Prdm13 in the DMH ameliorated increased sleep attempts during SD in old mice. Therefore, maintaining Prdm13 signaling in the DMH might play an important role to control sleep-wake patterns during aging.

Nampt/PBEF/Visfatin regulates insulin secretion in beta cells as a systemic NAD biosynthetic enzyme.

Intracellular nicotinamide phosphoribosyltransferase (iNampt) is an essential enzyme in the NAD biosynthetic pathway. An extracellular form of this protein (eNampt) has been reported to act as a cytokine named PBEF or an insulin-mimetic hormone named visfatin, but its physiological relevance remains controversial. Here we show that eNampt does not exert insulin-mimetic effects in vitro or in vivo but rather exhibits robust NAD biosynthetic activity. Haplodeficiency and chemical inhibition of Nampt cause defects in NAD biosynthesis and glucose-stimulated insulin secretion in pancreatic islets in vivo and in vitro. These defects are corrected by administration of nicotinamide mononucleotide (NMN), a product of the Nampt reaction. A high concentration of NMN is present in mouse plasma, and plasma eNampt and NMN levels are reduced in Nampt heterozygous females. Our results demonstrate that Nampt-mediated systemic NAD biosynthesis is critical for beta cell function, suggesting a vital framework for the regulation of glucose homeostasis.

A case of problems in supporting a patient after Y-chromosome long arm microdeletion testing at a Japanese general hospital.

There are only few reports on the problems faced post-Y-chromosome microdeletion tests that decide the use of micro testicular sperm extraction. We report a case wherein we faced issues in supporting a patient post-testing. One patient with azoospermia factor c (AZFc) deletion gave birth to a baby boy, who could have inherited the AZFc deletion; however, we could not inform the young patient. Therefore, it is necessary to establish a post-testing support system for patients and infants.