Adiponectin receptor agonist AdipoRon improves skeletal muscle function in aged mice

The loss of skeletal muscle function with age, known as sarcopenia, significantly reduces independence and quality of life and can have significant metabolic consequences. Although exercise is effective in treating sarcopenia it is not always a viable option clinically, and currently, there are no pharmacological therapeutic interventions for sarcopenia. Here, we show that chronic treatment with pan-adiponectin receptor agonist AdipoRon improved muscle function in male mice by a mechanism linked to skeletal muscle metabolism and tissue remodeling. In aged mice, 6 weeks of AdipoRon treatment improved skeletal muscle functional measures in vivo and ex vivo. Improvements were linked to changes in fiber type, including an enrichment of oxidative fibers, and an increase in mitochondrial activity. In young mice, 6 weeks of AdipoRon treatment improved contractile force and activated the energy-sensing kinase AMPK and the mitochondrial regulator PGC-1a (peroxisome proliferator-activated receptor gamma coactivator one alpha). In cultured cells, the AdipoRon induced stimulation of AMPK and PGC-1a was associated with increased mitochondrial membrane potential, reorganization of mitochondrial architecture, increased respiration, and increased ATP production. Furthermore, the ability of AdipoRon to stimulate AMPK and PGC1a was conserved in nonhuman primate cultured cells. These data show that AdipoRon is an effective agent for the prevention of sarcopenia in mice and indicate that its effects translate to primates, suggesting it may also be a suitable therapeutic for sarcopenia in clinical application.

PGC-1a integrates a metabolism and growth network linked to caloric restriction

Deleterious changes in energy metabolism have been linked to aging and disease vulnerability, while activation of mitochondrial pathways has been linked to delayed aging by caloric restriction (CR). The basis for these associations is poorly understood, and the scope of impact of mitochondrial activation on cellular function has yet to be defined. Here, we show that mitochondrial regulator PGC-1a is induced by CR in multiple tissues, and at the cellular level, CR-like activation of PGC-1a impacts a network that integrates mitochondrial status with metabolism and growth parameters. Transcriptional profiling reveals that diverse functions, including immune pathways, growth, structure, and macromolecule homeostasis, are responsive to PGC-1a. Mechanistically, these changes in gene expression were linked to chromatin remodeling and RNA processing. Metabolic changes implicated in the transcriptional data were confirmed functionally including shifts in NAD metabolism, lipid metabolism, and membrane lipid composition. Delayed cellular proliferation, altered cytoskeleton, and attenuated growth signaling through post-transcriptional and post-translational mechanisms were also identified as outcomes of PGC-1a-directed mitochondrial activation. Furthermore, in vivo in tissues from a genetically heterogeneous mouse population, endogenous PGC-1a expression was correlated with this same metabolism and growth network. These data show that small changes in metabolism have broad consequences that arguably would profoundly alter cell function. We suggest that this PGC-1a sensitive network may be the basis for the association between mitochondrial function and aging where small deficiencies precipitate loss of function across a spectrum of cellular activities.

Acetyl-CoA flux regulates the proteome and acetyl-proteome to maintain intracellular metabolic crosstalk

AT-1/SLC33A1 is a key member of the endoplasmic reticulum (ER) acetylation machinery, transporting acetyl-CoA from the cytosol into the ER lumen where acetyl-CoA serves as the acetyl-group donor for Nε-lysine acetylation. Dysfunctional ER acetylation, as caused by heterozygous or homozygous mutations as well as gene duplication events of AT-1/SLC33A1, has been linked to both developmental and degenerative diseases. Here, we investigate two models of AT-1 dysregulation and altered acetyl-CoA flux: AT-1^S113R/+ mice, a model of AT-1 haploinsufficiency, and AT-1 sTg mice, a model of AT-1 overexpression. The animals display distinct metabolic adaptation across intracellular compartments, including reprogramming of lipid metabolism and mitochondria bioenergetics. Mechanistically, the perturbations to AT-1-dependent acetyl-CoA flux result in global and specific changes in both the proteome and the acetyl-proteome (protein acetylation). Collectively, our results suggest that AT-1 acts as an important metabolic regulator that maintains acetyl-CoA homeostasis by promoting functional crosstalk between different intracellular organelles.

The Endoplasmic Reticulum acetylation machinery ensures proper quality control and disposal of newly folded proteins transiting the secretory pathway. Here, the authors show that this machinery acts as a metabolic regulator of acetyl-CoA homeostasis, impacting intracellular crosstalk.

Aging and Caloric Restriction Research: A Biological Perspective With Translational Potential

Aging as a research pursuit is fairly new compared with traditional lines of medical research. A growing field of investigators is focused on understanding how changes in tissue biology, physiology, and systemic homeostasis, conspire to create increased vulnerability to disease as a function of age. Aging research as a discipline is necessarily broad; in part because aging itself is multi-faceted and in part because different model systems are employed to define the underlying biology. In this review we outline aspects of aging research that are likely to uncover the pivotal events leading to age-related disease vulnerability. We focus on studies of human aging and discuss the value of research on caloric restriction, an intervention with proven efficacy in delaying aging. We propose that studies such as these will deliver target factors and processes that create vulnerability in human aging, an advance that would potentially be transformative in clinical care.

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Caloric restriction delays aging and is a powerful tool for understanding the biology of age-related disease vulnerability.

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Mechanisms induced by CR hold promise for the development of interventions for age-associated disease.

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Nonhuman primates are an excellent model for transition from biological insight to human clinical application.

Aging and caloric restriction impact adipose tissue, adiponectin, and circulating lipids

Adipose tissue expansion has been associated with system-wide metabolic dysfunction and increased vulnerability to diabetes, cancer, and cardiovascular disease. A reduction in adiposity is a hallmark of caloric restriction (CR), an intervention that extends longevity and delays the onset of these same age-related conditions. Despite these parallels, the role of adipose tissue in coordinating the metabolism of aging is poorly defined. Here, we show that adipose tissue metabolism and secretory profiles change with age and are responsive to CR. We conducted a cross-sectional study of CR in adult, late-middle-aged, and advanced-aged mice. Adiposity and the relationship between adiposity and circulating levels of the adipose-derived peptide hormone adiponectin were age-sensitive. CR impacted adiposity but only levels of the high molecular weight isoform of adiponectin responded to CR. Activators of metabolism including PGC-1a, SIRT1, and NAMPT were differentially expressed with CR in adipose tissues. Although age had a significant impact on NAD metabolism, as detected by biochemical assay and multiphoton imaging, the impact of CR was subtle and related to differences in reliance on oxidative metabolism. The impact of age on circulating lipids was limited to composition of circulating phospholipids. In contrast, the impact of CR was detected in all lipid classes regardless of age, suggesting a profound difference in lipid metabolism. These data demonstrate that aspects of adipose tissue metabolism are life phase specific and that CR is associated with a distinct metabolic state, suggesting that adipose tissue signaling presents a suitable target for interventions to delay aging.

Synthesis and characterization of tritylthioethanamine derivatives with potent KSP inhibitory activity

Assembly of a bipolar mitotic spindle requires the action of class 5 kinesins, and inhibition or depletion of this motor results in mitotic arrest and apoptosis. S-Trityl-l-cysteine is an allosteric inhibitor of vertebrate Kinesin Spindle Protein (KSP) that has generated considerable interest due to its anti-cancer properties, however, poor pharmacological properties have limited the use of this compound. We have modified the triphenylmethyl and cysteine groups, guided by biochemical and cell-based assays, to yield new cysteinol and cysteamine derivatives with increased inhibitory activity, greater efficacy in model systems, and significantly enhanced potency against the NCI60 tumor panel. These results reveal a promising new class of conformationally-flexible small molecules as allosteric KSP inhibitors for use as research tools, with activities that provide impetus for further development as anti-tumor agents.

Techniques for identifying the epidural space: a survey of practice amongst anaesthetists in the UK

A postal survey of all UK members of the Obstetric Anaesthetists' Association was carried out to ascertain their preferred method for identifying the epidural space in obstetric and non-obstetric patients. Over 1200 questionnaires were returned (79.3% response rate). In obstetric patients, the single most common technique (used by 58% of anaesthetists) was continuous advancement of the epidural needle and loss of resistance with saline, followed by intermittent needle advancement with air (21%). A minority of respondents used other variants, including intermittent advancement with saline (16%) and continuous advancement with air (4%). Consultant anaesthetists showed greater variety in techniques used than did trainees (p < 0.001). Less than 5% of respondents used a paramedian approach, and these were almost exclusively senior staff. Only 48% of anaesthetists said they would try an alternative if they experienced difficulty with their preferred technique. A similar pattern was seen for lumbar epidurals in non-obstetric surgical patients (89% used the same technique as in obstetrics), although for thoracic epidurals, 23% used a different technique to that which they would use for obstetrics, and the paramedian approach was more popular (21%). When inserting lumbar epidurals to supplement general anaesthesia in surgical patients, 18% of anaesthetists said they usually performed the block with the patient asleep, whereas for thoracic epidurals, this figure fell to 14%.

A comparison of epidural ropivacaine 0.75% and bupivacaine 0.5% with fentanyl for elective caesarean section

BACKGROUND

Early studies suggested that ropivacaine had clinical advantages over bupivacaine with respect to cardiotoxicity and motor block, and that it was suitable for epidural caesarean section. This study was set up to compare epidural 0.75% ropivacaine with a popular bupivacaine/fentanyl mixture for elective caesarean section.

METHODS

Eighty women having elective caesarean section under epidural anaesthesia were randomly allocated to receive 20 mL of either 0.75% ropivacaine or 0.5% bupivacaine plus fentanyl 100 microg. Supplementation with 2% plain lidocaine was used where necessary. Times were recorded for onset of sensory block, density and duration of motor block, and the need for supplementation.

RESULTS

There was no difference between the groups in the time (mean [SD]) to achieve sensory blockade to cold to T4 (ropivacaine 15.8 [5.6] min, bupivacaine/fentanyl 18.7 [9.1] min, P=0.13) or to S1 (ropivacaine 18.3 [4.6] min, bupivacaine/fentanyl 17.4 [7.6] min, P=0.59), or in the need for supplementation. However, ropivacaine produced a motor block that was denser (median Bromage score ropivacaine 3, bupivacaine/fentanyl 1.5, P=0.0041), and of longer duration (ropivacaine 237 [84] min, bupivacaine/fentanyl 144 [76] min, P<0.0001).

CONCLUSIONS

This study suggests that epidural 0.75% ropivacaine without opioid may be used as an alternative to bupivacaine 0.5% with fentanyl for elective caesarean section, but it does not induce anaesthesia any faster and may result in a denser, more prolonged, motor block.

Administration of drugs outside of Product Licence: awareness and current practice

An interactive audience response system was used to collect information from members of the Obstetric Anaesthetists' Association at the 1997 Annual Meeting about the drug use that is unsupported by the Product Licence. The responses confirm that both licensed and unlicensed drugs are widely used in clinical practice outside the limitations imposed by Product Licence. The commonest types of unlicensed administration in obstetric anaesthetic practice are the use of mixtures and epidural or spinal administration of opioids. Despite widespread awareness of the subject, there appears to be considerable ignorance about the indications for which many commonly used drugs are licensed, even amongst a specialist audience. A majority of audience members expressed a view that the OAA should play a pro-active role, either by polling members about their current practice, or by issuing guidelines on reasonable drug practice in obstetric anaesthesia, or both. Potential implications of these are discussed.

Physostigmine: going ... going ... gone? Two cases of central anticholinergic syndrome following anaesthesia and its treatment with physostigmine

Two patients presented with very different signs of central anticholinergic syndrome following general anaesthesia for which they had received premedication with hyoscine. Both responded dramatically to 1 mg of intravenous (i.v.) physostigmine, which produced a rapid return to a normal level of consciousness. The aetiology of central anticholinergic syndrome is multi-factorial, but the diagnosis should be considered in all patients who demonstrate abnormal post-anaesthetic awakening. It is recommended that 1 mg of intravenous physostigmine is a safe and effective treatment for central anticholinergic syndrome, and that a supply of this important drug must be kept readily available in the recovery area of the operating theatre department.

Patient-controlled analgesia following caesarean section under general anaesthesia: a comparison of fentanyl with morphine

This prospective, randomised, double-blind study compared PCA fentanyl with PCA morphine for post-Caesarean section analgesia. Following a standardised general anaesthetic, 37 women were allocated to receive either fentanyl (n = 18) or morphine (n = 19). The PCA was commenced after the women had been made comfortable in the postanaesthetic recovery room with the appropriate opioid solution (mean dose required = fentanyl 375 micrograms or morphine 16 mg). Initial PCA settings were bolus 1 ml (fentanyl 25 micrograms or morphine 1 mg), lockout time ten minutes, and no background infusion. Both analgesic solutions provided effective analgesia for a mean of 37 hr with high levels of patient satisfaction, and there were no differences in VAS scores for pain and patient satisfaction, or for side effects (nausea, itch, and sleepiness) between fentanyl or morphine. However, more patients in the fentanyl group required supplementary boluses or alterations to the PCA settings (13/18 vs 4/19: P = 0.005), and one patient was removed from the study due to inadequate analgesia. We conclude that fentanyl is not recommended for routine PCA use following Caesarean section.

Anaesthesia for the parturient with cystic fibrosis

Cystic fibrosis is an inherited disorder that primarily affects the exocrine glands of the gastrointestinal and respiratory systems. It is commonly diagnosed at birth or shortly thereafter, and until recently few of these patients lived to reproductive age. However, as a result of improved medical care, there are now an increasing number of pregnancies in women with cystic fibrosis. We present the histories of two parturients with cystic fibrosis and discuss the anaesthetic and perinatal implications of this complex disease to their management.

Lupus anticoagulant, paramyotonia congenita and pregnancy

A case report is presented of the anaesthetic management of a parturient with paramyotonia congenita and lupus anticoagulant antibodies. She had been treated with prophylactic, subcutaneous heparin and aspirin throughout her pregnancy. Epidural analgesia was provided for labour and delivery.

An experience of war surgery and wounds presenting after 3 days on the border of Afghanistan

The International Committee of the Red Cross (ICRC) has run hospitals for the wounded of the conflict in Afghanistan since 1981. For political and geographical reasons the hospitals are situated in Pakistan, some distance from the fighting, and so the wounded may take many days to arrive. This has enabled a surgical team provided by the British Red Cross Society to observe wounds of varying age and degrees of putrefaction or healing. Twenty-nine (29) patients with wounds of 3 or more days are detailed. The old wounds showed a tendency either to putrefaction or healing and the surgical management had to be revised accordingly. Wounds sutured in the field tended to putrefy. Among the various problems, the most taxing and difficult were the cultural and religious objections to amputation. The ICRC is committed to providing surgical hospitals for the Afghan war wounded for as long as the conflict lasts. It has adapted the local facilities and staff to the particular political, geographical and cultural situation.