Data from network meta-analyses can inform clinical practice guidelines and decision-making in diabetes management: perspectives of the taskforce of the guideline workshop.

In recent years, several novel agents have become available to treat individuals with type 2 diabetes (T2D), such as sodium-glucose cotransporter-2 inhibitors (SGLT-2i), tirzepatide, which is a dual glucose-dependent insulinotropic polypeptide receptor agonist (GIP RA)/glucagon-like peptide-1 receptor agonist (GLP-1 RA), and finerenone, a non-steroidal mineralocorticoid receptor antagonist (MRA) that confers significant renal and cardiovascular benefits in individuals with (CKD). New medications have the potential to improve the lives of individuals with diabetes. However, clinicians are challenged to understand the benefits and potential risks associated with these new and emerging treatment options. In this article, we discuss how use of network meta-analyses (NMA) can fill this need.

Clinical Performance Measures for Stroke Rehabilitation: Performance Measures From the American Heart Association/American Stroke Association.

The American Heart Association/American Stroke Association released the adult stroke rehabilitation and recovery guidelines in 2016. A working group of stroke rehabilitation experts reviewed these guidelines and identified a subset of recommendations that were deemed suitable for creating performance measures. These 13 performance measures are reported here and contain inclusion and exclusion criteria to allow calculation of rates of compliance in a variety of settings ranging from acute hospital care to postacute care and care in the home and outpatient setting.

Angiotensin type 1a receptors in the median preoptic nucleus support intermittent hypoxia-induced hypertension.

Chronic intermittent hypoxia (CIH) is a model of the hypoxemia from sleep apnea that causes a sustained increase in blood pressure. Inhibition of the central renin-angiotensin system or FosB in the median preoptic nucleus (MnPO) prevents the sustained hypertensive response to CIH. We tested the hypothesis that angiotensin type 1a (AT1a) receptors in the MnPO, which are upregulated by CIH, contribute to this hypertension. In preliminary experiments, retrograde tract tracing studies showed AT1a receptor expression in MnPO neurons projecting to the paraventricular nucleus. Adult male rats were exposed to 7 days of intermittent hypoxia (cycling between 21% and 10% O2 every 6 min, 8 h/day during light phase). Seven days of CIH was associated with a FosB-dependent increase in AT1a receptor mRNA without changes in the permeability of the blood-brain barrier in the MnPO. Separate groups of rats were injected in the MnPO with an adeno-associated virus containing short hairpin (sh)RNA against AT1a receptors to test their role in intermittent hypoxia hypertension. Injections of shRNA against AT1a in MnPO blocked the increase in mRNA associated with CIH, prevented the sustained component of the hypertension during normoxia, and reduced circulating advanced oxidation protein products, an indicator of oxidative stress. Rats injected with shRNA against AT1a and exposed to CIH had less FosB staining in MnPO and the rostral ventrolateral medulla after intermittent hypoxia than rats injected with the control vector that were exposed to CIH. Our results indicate AT1a receptors in the MnPO contribute to the sustained blood pressure increase to intermittent hypoxia.

Role of angiotensin-converting enzyme 1 within the median preoptic nucleus following chronic intermittent hypoxia.

Sustained hypertension is an important consequence of obstructive sleep apnea. An animal model of the hypoxemia associated with sleep apnea, chronic intermittent hypoxia (CIH), produces increased sympathetic nerve activity (SNA) and sustained increases in blood pressure. Many mechanisms have been implicated in the hypertension associated with CIH, including the role of ΔFosB within the median preoptic nucleus (MnPO). Also, the renin-angiotensin system (RAS) has been associated with CIH hypertension. We conducted experiments to determine the possible association of FosB/ΔFosB with a RAS component, angiotensin-converting enzyme 1 (ACE1), within the MnPO following 7 days of CIH. Retrograde tract tracing from the paraventricular nucleus (PVN), a downstream region of the MnPO, was used to establish a potential pathway for FosB/ΔFosB activation of MnPO ACE1 neurons. After CIH, ACE1 cells with FosB/ΔFosB expression increased colocalization with a retrograde tracer that was injected unilaterally within the PVN. Also, Western blot examination showed ACE1 protein expression increasing within the MnPO following CIH. Chromatin immunoprecipitation (ChIP) assays demonstrated an increase in FosB/ΔFosB association with the ACE1 gene within the MnPO following CIH. FosB/ΔFosB may transcriptionally target ACE1 within the MnPO following CIH to affect the downstream PVN region, which may influence SNA and blood pressure.

Angiotensin II type 1a receptors in subfornical organ contribute towards chronic intermittent hypoxia-associated sustained increase in mean arterial pressure.

Sleep apnea is associated with hypertension. The mechanisms contributing to a sustained increase in mean arterial pressure (MAP) even during normoxic awake-state remain unknown. Rats exposed to chronic intermittent hypoxia for 7 days, a model of the hypoxemia associated with sleep apnea, exhibit sustained increases in MAP even during the normoxic dark phase. Activation of the renin-angiotensin system (RAS) has been implicated in chronic intermittent hypoxia (CIH) hypertension. Since the subfornical organ (SFO) serves as a primary target for the central actions of circulating ANG II, we tested the effects of ANG II type 1a receptor (AT1aR) knockdown in the SFO on the sustained increase in MAP in this CIH model. Adeno-associated virus carrying green fluorescent protein (GFP) and small-hairpin RNA against either AT1aR or a scrambled control sequence (SCM) was stereotaxically injected in the SFO of rats. After recovery, MAP, heart rate, respiratory rate, and activity were continuously recorded using radiotelemetry. In the normoxic groups, the recorded variables did not deviate from the baseline values. Both CIH groups exhibited significant increases in MAP during CIH exposures (P < 0.05). During the normoxic dark phase in the CIH groups, only the SCM-injected group exhibited a sustained increase in MAP (P < 0.05). The AT1aR-CIH group showed significant decreases in FosB/ΔFosB staining in the median preoptic nucleus and the paraventricular nuclei of the hypothalamus compared with the SCM-CIH group. Our data indicate that AT1aRs in the SFO are critical for the sustained elevation in MAP and increased FosB/ΔFosB expression in forebrain autonomic nuclei associated with CIH.

Differential regulation of TRPC4 in the vasopressin magnocellular system by water deprivation and hepatic cirrhosis in the rat.

Transient receptor potential canonical subtype 4 (TRPC4) is expressed in the magnocellular paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus. In this study, the regulation of TRPC4 expression was investigated in water deprivation and hepatic cirrhosis. We used laser capture microdissection technique for precise dissection of pure AVP cell population in the PVN and SON followed by quantitative real-time RT-PCR, and immunodetection techniques by Western blot analysis and immunofluorescence. Bile duct ligation elevated TRPC4 transcripts in the SON but not PVN with correlated changes in the protein expression in these regions, as well as increased colocalization with AVP in the SON, with no changes in the PVN. Water deprivation resulted in increased TRPC4 mRNA expression in the PVN, while it decreased channel expression levels in the SON. In both of these regions, protein expression measured from tissue punches were unaltered following water deprivation, with no changes in the number of TRPC4-positive cells. Thus, TRPC4 expression is differentially regulated in physiological and pathophysiological models of vasopressin release.

ANG II receptor subtype 1a gene knockdown in the subfornical organ prevents increased drinking behavior in bile duct-ligated rats.

Bile duct ligation (BDL) causes congestive liver failure that initiates hemodynamic changes, resulting in dilutional hyponatremia due to increased water intake and vasopressin release. This project tested the hypothesis that angiotensin signaling at the subfornical organ (SFO) augments drinking behavior in BDL rats. A genetically modified adeno-associated virus containing short hairpin RNA (shRNA) for ANG II receptor subtype 1a (AT1aR) gene was microinjected into the SFO of rats to knock down expression. Two weeks later, BDL or sham surgery was performed. Rats were housed in metabolic chambers for measurement of fluid and food intake and urine output. The rats were euthanized 28 days after BDL surgery for analysis. A group of rats was perfused for immunohistochemistry, and a second group was used for laser-capture microdissection for analysis of SFO AT1aR gene expression. BDL rats showed increased water intake that was attenuated in rats that received SFO microinjection of AT1aR shRNA. Among BDL rats treated with scrambled (control) and AT1aR shRNA, we observed an increased number of vasopressin-positive cells in the supraoptic nucleus that colocalized with ΔFosB staining, suggesting increased vasopressin release in both groups. These results indicate that angiotensin signaling through the SFO contributes to increased water intake, but not dilutional hyponatremia, during congestive liver failure.

Angiotensin II induces membrane trafficking of natively expressed transient receptor potential vanilloid type 4 channels in hypothalamic 4B cells.

Transient receptor potential vanilloid family type 4 (TRPV4) channels are expressed in central neuroendocrine neurons and have been shown to be polymodal in other systems. We previously reported that in the rodent, a model of dilutional hyponatremia associated with hepatic cirrhosis, TRPV4 expression is increased in lipid rafts from the hypothalamus and that this effect may be angiotensin dependent. In this study, we utilized the immortalized neuroendocrine rat hypothalamic 4B cell line to more directly test the effects of angiotensin II (ANG II) on TRPV4 expression and function. Our results demonstrate the expression of corticotropin-releasing factor (CRF) transcripts, for sex-determining region Y (SRY) (male genotype), arginine vasopressin (AVP), TRPV4, and ANG II type 1a and 1b receptor in 4B cells. After a 1-h incubation in ANG II (100 nM), 4B cells showed increased TRPV4 abundance in the plasma membrane fraction, and this effect was prevented by the ANG II type 1 receptor antagonist losartan (1 µM) and by a Src kinase inhibitor PP2 (10 µM). Ratiometric calcium imaging experiments demonstrated that ANG II incubation potentiated TRPV4 agonist (GSK 1016790A, 20 nM)-induced calcium influx (control 18.4 ± 2.8% n = 5 and ANG II 80.5 ± 2.4% n = 5). This ANG II-induced increase in calcium influx was also blocked by 1 µM losartan and 10 µM PP2 (losartan 26.4 ± 3.8% n = 5 and PP2 19.7 ± 3.9% n = 5). Our data suggests that ANG II can increase TRPV4 channel membrane expression in 4B cells through its action on AT1R involving a Src kinase pathway.

Central losartan attenuates increases in arterial pressure and expression of FosB/ΔFosB along the autonomic axis associated with chronic intermittent hypoxia.

Chronic intermittent hypoxia (CIH) increases mean arterial pressure (MAP) and FosB/ΔFosB staining in central autonomic nuclei. To test the role of the brain renin-angiotensin system (RAS) in CIH hypertension, rats were implanted with intracerebroventricular (icv) cannulae delivering losartan (1 µg/h) or vehicle (VEH) via miniosmotic pumps and telemetry devices for arterial pressure recording. A third group was given the same dose of losartan subcutaneously (sc). Two groups of losartan-treated rats served as normoxic controls. Rats were exposed to CIH or normoxia for 7 days and then euthanized for immunohistochemistry. Intracerebroventricular losartan attenuated CIH-induced increases in arterial pressure during CIH exposure (0800-1600 during the light phase) on days 1, 6, and 7 and each day during the normoxic dark phase. FosB/ΔFosB staining in the organum vasculosum of the lamina terminalis (OVLT), median preoptic nucleus (MnPO), paraventricular nucleus of the hypothalamus (PVN), the rostral ventrolateral medulla (RVLM), and the nucleus of the solitary tract (NTS) was decreased in icv losartan-treated rats. Subcutaneous losartan also reduced CIH hypertension during the last 2 days of CIH and produced bradycardia prior to the effect on blood pressure. Following sc losartan, FosB/ΔFosB staining was reduced only in the OVLT, MnPO, PVN, and NTS. These data indicate that the central and peripheral RAS contribute to CIH-induced hypertension and transcriptional activation of autonomic nuclei and that the contribution of the central RAS is greater during the normoxic dark phase of CIH hypertension.

Guideline Development for Medical Device Technology: Issues for Consideration.

Advances in the development of innovative medical devices and telehealth technologies create the potential to improve the quality and efficiency of diabetes care through collecting, aggregating, and interpreting relevant health data in ways that facilitate more informed decisions among all stakeholder groups. Although many medical societies publish guidelines for utilizing these technologies in clinical practice, we believe that the methodologies used for the selection and grading of the evidence should be revised. In this article, we discuss the strengths and limitations of the various types of research commonly used for evidence selection and grading and present recommendations for modifying the process to more effectively address the rapid pace of device and technology innovation and new product development.

Site-specific effects of intracranial estradiol administration on recurrent insulin-induced hypoglycemia in the ovariectomized female rat.

Clinical and experimental studies reveal gender differences in susceptibility to dampening effects of precedent hypoglycemia on recurrent insulin-induced hypoglycemia (RIIH). Recent studies implicate the ovarian steroid, estradiol, in the regulation of RIIH, since systemic replacement of this hormone at basal estrous cycle levels maintains glucose profiles during serial insulin dosing and prevents RIIH-associated reductions in neuronal activation in key metabolic structures in the ovariectomized female rat brain. The present study investigated the hypothesis that these effects are achieved, in part, by estrogenic action within the central nervous system, including glucoregulatory structures characterized by high estrogen receptor (ER) expression. Initial experiments evaluated the impact of global intracranial administration of estradiol on RIIH. Ovariectomized rats were treated by continuous infusion of graded doses of 17ß-estradiol-3-benzoate (EB) or vehicle into the lateral ventricle (LV), and injected subcutaneously with 1 or 4 doses of the intermediate-release insulin, Humulin N (HN), 1 dose per day. Animals infused with 5 or 10 µg EB/day exhibited uniform glycemic responses to 1 versus 4 doses of insulin, whereas rescue from hypoglycemia was delayed during repetitive HN injection of rats infused with either vehicle or 1 µg EB/day. Recovery from both single and multiple bouts of hypoglycemia was more rapid in rats infused with the higher EB doses, compared to other groups. Mapping of ERα immunoreactivity in animals treated by LV infusion of EB revealed variable nuclear staining in ER-expressing metabolic loci typified by estrogen-dependent sustenance of neuronal reactivity to hypoglycemia, with highest levels of ERα immunoreactivity observed in the arcuate (ARH) and ventromedial (VMH) hypothalamic nuclei, and moderate labeling of the caudal hindbrain dorsal vagal complex. EB delivery to the caudal hindbrain via the caudal fourth ventricle resulted in dose-dependent effects on RIIH, since glycemic profiles were either unchanged or diminished relative to acute NH-induced hypoglycemia, in high versus low EB-treated animals, respectively. Bilateral administration of 1.0 µg EB into the ARH or VMH elicited disparate effects on acute and chronic HN-induced hypoglycemia. Intra-VMH EB delayed recovery from both acute and chronic hypoglycemia, compared to non-estradiol-treated controls. In contrast, neither that dose nor a 10-fold lower dosage of EB delivered to the ARH modified acute HN-induced hypoglycemia, but RIIH was either attenuated or enhanced, respectively, in animals treated by intra-ARH delivery of 1.0 versus 0.1 µg EB, respectively. These results suggest that whole brain exposure to elevated estradiol may promote outflow that truncates hypoglycemia and maintains glucose profiles during RIIH, whereas actions of relatively low hormone levels on the central nervous system may result in adaptive adjustments that result in lower blood glucose levels during recurring versus acute hypoglycemia. The data also imply that, at a given concentration, estrogens may exert site-specific effects on acute and chronic HN-induced hypoglycemia. Further research is needed to identify the cellular substrates and physiological mechanisms that mediate caudal hindbrain-, ARH-, and VMH-specific actions of estradiol on acute and chronic hypoglycemia.

Sex differences in acclimation of hypothalamic arcuate glucokinase gene and protein expression to repeated intermediate insulin administration.

BACKGROUND: Repeated intermediate-acting insulin administration attenuates genomic reactivity of neurons in key autonomic metabolic structures in the male, but not female rat brain - results that support a central neural component of sex-specific response desensitization. The glucokinase (GK) enzyme functions as a glucose sensor in a body-wide system of metabolic monitoring structures, including the brain, and is expressed at high levels in the hypothalamic arcuate nucleus (ARH). METHOD: Quantitative real-time RT-PCR was used to investigate the hypothesis that habituation of ARH GK gene expression to neutral protamine Hagedorn insulin (NPH) injection differs among sexes. In lieu of evidence for region-based functional heterogeneity in this structure, effects of NPH on in situ GK protein-staining patterns were evaluated at different rostrocaudal levels of the ARH by immunocytochemistry. RESULTS: Basal ARH GK mRNA levels were equivalent in sham-operated (SHAM) and orchidectomized (ORDX) male rats. SHAM males exhibited augmented GK gene profiles in response to acute NPH injection, as well as elevated numbers of GK-immunoreactive (-ir) neurons in the rostral ARH. ORDX abolished this stimulatory transcriptional response, but did not prevent increased GK labeling throughout this structure. Stimulatory effects of precedent insulin administration on baseline GK mRNA were reversed by ORDX. Serial dosing of SHAM males with NPH elicited no change in ARH GK transcription, but decreased GK-ir in the rostral ARH. Acute NPH injection had no impact on GK gene profiles in estradiol benzoate (EB)- or oil-implanted ovariectomized (OVX) female rats, but diminished GK-ir cell counts in the OVX + EB caudal ARH. Precedent NPH treatment did not modify baseline GK mRNA levels in either group of females, but resulted in decreased or elevated GK gene and protein expression during recurring injection in the presence or absence of EB, respectively. CONCLUSION: These results provide novel evidence for sex-specific patterns of acclimation of GK mRNA and protein expression within the rat ARH to serial NPH injection, and support the need to elucidate the physiological ramifications of these adaptations regarding behavioral and physiological responses to recurring intermediate insulin administration.

Effects of estradiol on acute and recurrent insulin-induced hypoglycemia-associated patterns of arcuate neuropeptide Y, proopiomelanocortin, and cocaine- and amphetamine-related transcript gene expression in the ovariectomized rat.

The ovarian steroid hormone, estradiol, is one of several peripheral metabolic signal modulators that are integrated at the level of the arcuate nucleus of the hypothalamus (ARH), and is implicated in the control of ARH neuropeptides that maintain energy balance, including neuropeptide Y (NPY) and proopiomelanocortin (POMC). The present studies utilized quantitative real-time RT-PCR techniques to examine the hypothesis that estradiol regulates ARH NPY, POMC, and cocaine- and amphetamine-related transcript (CART) gene expression during acute insulin-induced hypoglycemia (IIH) and that adaptive modifications in transcriptional reactivity during recurring exposure are steroid dependent. ARH tissue was obtained by micropunch dissection from estradiol benzoate- and oil-implanted ovariectomized (OVX) rats that were treated by subcutaneous injection of one or four doses of the intermediate insulin formulation, Humulin NPH, over as many days, or vehicle alone. Our data show that in OVX plus estradiol benzoate and OVX plus oil groups, a single injection of insulin did not modify gene expression profiles, with the exception of acute hypoglycemic reduction of ARH NPY transcripts in the presence of estrogen. Prior exposure to daily hypoglycemia significantly diminished basal NPY and POMC mRNA levels in estradiol benzoate-, but not oil-implanted OVX rats, but elevated baseline CART transcripts in oil-treated animals. Recurring IIH enhanced ARH NPY gene expression relative to baseline, irrespective of the estradiol manipulation, but net tissue levels were greater in the absence of estrogen. In contrast, reexposure to hypoglycemia decreased POMC and CART gene transcription in estradiol benzoate- and oil-implanted OVX animals, respectively, relative to the single-dose groups. These studies show that estrogen modulates the impact of precedent exposure to IIH on basal and/or hypoglycemia-associated patterns of expression of ARH neuropeptide genes of characterized significance for energy homeostasis. The novel evidence for transcriptional acclimation of NPY, POMC, and CART to recurring IIH supports the possibility that adaptation of compensatory behavioral and physiological responses to acute versus chronic exposure to this metabolic stress may reflect neural regulatory mechanisms involving one or more neurotransmitters encoded by these genes.

Angiotensin converting enzyme 1 in the median preoptic nucleus contributes to chronic intermittent hypoxia hypertension.

Obstructive sleep apnea is associated with hypertension and cardiovascular disease. Chronic intermittent hypoxia is used to model the arterial hypoxemia seen in sleep apnea patients and is associated with increased sympathetic nerve activity and a sustained diurnal increase in blood pressure. The renin angiotensin system has been associated with hypertension seen in chronic intermittent hypoxia. Angiotensin converting enzyme 1, which cleaves angiotensin I to the active counterpart angiotensin II, is present within the central nervous system and has been shown to be regulated by AP-1 transcription factors, such as ΔFosB. Our previous study suggested that this transcriptional regulation in the median preoptic nucleus contributes to the sustained blood pressure seen following chronic intermittent hypoxia. Viral mediated delivery of a short hairpin RNA against angiotensin converting enzyme 1 in the median preoptic nucleus was used along with radio-telemetry measurements of blood pressure to test this hypothesis. FosB immunohistochemistry was utilized in order to assess the effects of angiotensin converting enzyme 1 knockdown on the activity of nuclei downstream from median preoptic nucleus. Angiotensin converting enzyme 1 knockdown within median preoptic nucleus significantly attenuated the sustained hypertension seen in chronic intermittent hypoxia. Angiotensin converting enzyme 1 seems to be partly responsible for regulating downstream regions involved in sympathetic and blood pressure control, such as the paraventricular nucleus and the rostral ventrolateral medulla. The data suggest that angiotensin converting enzyme 1 within median preoptic nucleus plays a critical role in the sustained hypertension seen in chronic intermittent hypoxia.

Effects of intracerebroventricular administration of the NPY-Y1 receptor antagonist, 1229U91, on hyperphagic and glycemic responses to acute and chronic intermediate insulin-induced hypoglycemia in female rats.

Neuropeptide Y (NPY) Y1 receptors are implicated in CNS regulation of food intake, but their role in hypoglycemic hyperphagia remains unclear. The present studies utilized a pharmacological approach to investigate the hypothesis that NPY acts via Y1 receptor-dependent mechanisms to regulate feeding and blood glucose profiles during intermediate insulin-induced hypoglycemia. Groups of ovariectomized, estradiol benzoate-treated female rats were injected subcutaneously with one or four doses of neutral protamine Hagedorn insulin (NPH), on as many days, or with diluent alone. Before final treatments on day four, the animals were pretreated by intracerebroventricular (icv) delivery of the NPY Y1 receptor antagonist, 1229U91, or the vehicle, artificial cerebrospinal fluid (acsf). Food intake during acute hypoglycemia was significantly diminished between t(o) and +2 h in animals pretreated with the Y1 receptor antagonist versus vehicle. Administration of 1229U91 prior to the fourth of four NPH doses suppressed hypoglycemic hyperphagia over a relatively longer interval, e.g. 4 h, after t(o) relative to the acute insulin group. Blood glucose levels after a single NPH injection were similar in acsf- and antagonist-pretreated rats at +2, +4, and +6 h, but were lower at +9 h in the latter group. Pretreatment with 1229U91 did not modify glucose profiles between +2 and +9 h after multiple dosing with NPH, but prevented recovery from hypoglycemia at +12 h. The present results show that central NPY Y1 receptor antagonism inhibits hypoglycemic hyperphagia, and that this suppressive effect on feeding was of greater duration during recurring hypoglycemia. The data also show that Y1 receptor blockade decreases glycemic responses to both single and serial NPH dosing, albeit at different post-injection time points. The current studies support the view that NPY Y1 receptors function within central neural pathways that govern feeding and glycemic responses to intermediate-acting insulin, and that Y1 receptor-mediated stimulation of food intake may habituate in a positive manner to repetitive insulin-induced hypoglycemia. Further research is needed to evaluate the impact of chronic insulin-induced hypoglycemia on neuropeptide Y neurotransmission and Y1 receptor expression within regulatory circuitries that control food intake and glucostasis.