Diagnosis and comprehensive treatment of a glucagonoma in a patient with residual intrahepatic metastases postoperatively: A case report and literature review

Glucagonomas are rare neuroendocrine neoplasms of the pancreas with malignant potential. At present, their epidemiology is not entirely clear, so clinicians are not well versed, lacking any consensus on diagnosis or comprehensive treatment. The present study reports the case of a 32-year-old woman hospitalized for recurrent glossitis, perioral dermatitis and necrolytic migratory erythema (NME) of both lower limbs. Imaging studies revealed a low-density nodule (~2 cm) in the tail of the pancreas, as well as multiple space-occupying hepatic lesions. Surgical intervention was then selected, and distal pancreatectomy, splenectomy and palliative metastasectomies were performed. Tissue examination subsequently confirmed a primary pancreatic neuroendocrine tumor (grade 2), metastatic to the liver. The NME resolved postoperatively, aided by intramuscular injections of long-acting release octreotide (30 mg) every 28 days. A series of three percutaneous ablative treatments (microwave ablation) were also undertaken within a 2-year period, targeting the liver metastases. The present condition of the patient is good, with no cutaneous relapse to date. Palliative metastasectomies, in conjunction with ablative treatments and combination somatostatin analog (SSA) use, are unique aspects of this case that, to the best of our knowledge, have yet to be documented in the literature. Surgical palliation may benefit patients with liver involvement and prolong their survival time. Likewise, ablative treatments and SSA injections delivered together not only address hepatic spread, but also control hormone-related symptoms, having a positive impact on prognosis. As glucagonomas are so rare, there is no real agreement on their management. The present study aims to guide clinical practice by adding further to the available data.

Immunocytochemical localization of nitric oxide synthase-containing neurons in the visual cortex of the Mongolian gerbil

INTRODUCTION

Nitric oxide (NO) is present in various cell types in the central nervous system and plays a crucial role in the control of various cellular functions. The diurnal Mongolian gerbil is a member of the rodent family Muridae that exhibits unique physiological, anatomical, and behavioral differences from the nocturnal rat and mouse, which render it a useful model for studying the visual system. The purpose of this study was to confirm the distribution and morphology of neurons that contain nitric oxide synthase (NOS) and their pattern of co-expressing NOS with neuropeptide Y (NPY), somatostatin (SST), and gamma-aminobutyric acid (GABA) in the visual cortex of Mongolian gerbils.

MATERIALS AND METHODS

Mongolian gerbils were used in the study. We confirmed the localization of NOS in the visual cortex of Mongolian gerbils using horseradish peroxidase immunocytochemistry, fluorescent immunocytochemistry, and conventional confocal microscopy.

RESULTS

NOS-immunoreactive (IR) neurons were present in all layers of the visual cortex of the Mongolian gerbil, with the exception of layer I, with the highest density observed in layer V (50.00%). The predominant type of NOS-IR neurons was multipolar round/oval cells (60.96%). Two-color immunofluorescence revealed that 100% NOS-IR neurons were co-labeled with NPY and SST and 34.55% were co-labeled with GABA.

CONCLUSIONS

Our findings of the laminar distribution and morphological characteristics of NOS-IR neurons, as well as the colocalization patterns of NOS-IR neurons with NPY, SST, and GABA, indicated the presence of species-specific differences, suggesting the functional diversity of NO in the visual cortex. This study provides valuable data on the anatomical organization of NOS-IR neurons and, consequently, a better understanding of the functional aspects of NO and species diversity.

Dosing lutetium Lu 177-dotatate for a hemodialysis patient

Lu177-dotatate (Lutathera™) is a radioactive drug approved for the treatment of adults with gastro-entero-pancreatic neuroendocrine tumors and is predominantly renally excreted. Currently all patients receive 7400 MBq (200 mCi), and there are no guidelines for treating hemodialysis patients. We measured radioactivity prior to and post administration of two cycles of Lu177-dotatate in a hemodialysis patient, and radiation exposure to staff. We reduced the standard 7400 MBq by 33% for the first cycle and patient radioactivity fell by 40% following postdilution hemodiafiltration started 6 h post dosing, and by 45% for the second cycle and radioactivity fell by 47% with postdilution hemodiafiltration started 5 h post administration. By reducing the initial administered radioactivity, coupled with early dialysis, and choosing postdilution hemodiafiltration we were able to achieve radioactivity retention curves similar to those from patients with normal renal function receiving the standard administration of 7400 MBq.

Astrocyte-secreted neurocan controls inhibitory synapse formation and function

Astrocytes strongly promote the formation and maturation of synapses by secreted proteins. Several astrocyte-secreted synaptogenic proteins controlling excitatory synapse development were identified; however, those that induce inhibitory synaptogenesis remain elusive. Here, we identify neurocan as an astrocyte-secreted inhibitory synaptogenic protein. After secretion from astrocytes, neurocan is cleaved into N- and C-terminal fragments. We found that these fragments have distinct localizations in the extracellular matrix. The neurocan C-terminal fragment localizes to synapses and controls cortical inhibitory synapse formation and function. Neurocan knockout mice lacking the whole protein or only its C-terminal synaptogenic domain have reduced inhibitory synapse numbers and function. Through super-resolution microscopy, in vivo proximity labeling by secreted TurboID, and astrocyte-specific rescue approaches, we discovered that the synaptogenic domain of neurocan localizes to somatostatin-positive inhibitory synapses and strongly regulates their formation. Together, our results unveil a mechanism through which astrocytes control circuit-specific inhibitory synapse development in the mammalian brain.

Long-range inhibitory neurons mediate cortical neurovascular coupling

To meet the high energy demands of brain function, cerebral blood flow (CBF) parallels changes in neuronal activity by a mechanism known as neurovascular coupling (NVC). However, which neurons play a role in mediating NVC is not well understood. Here, we identify in mice and humans a specific population of cortical GABAergic neurons that co-express neuronal nitric oxide synthase and tachykinin receptor 1 (Tacr1). Through whole-tissue clearing, we demonstrate that Tacr1 neurons extend local and long-range projections across functionally connected cortical areas. We show that whisker stimulation elicited Tacr1 neuron activity in the barrel cortex through feedforward excitatory pathways. Additionally, through optogenetic experiments, we demonstrate that Tacr1 neurons are instrumental in mediating CBF through the relaxation of mural cells in a similar fashion to whisker stimulation. Finally, by electron microscopy, we observe that Tacr1 processes contact astrocytic endfeet. These findings suggest that Tacr1 neurons integrate cortical activity to mediate NVC.

Parvalbumin and Somatostatin: Biomarkers for Two Parallel Tectothalamic Pathways in the Auditory Midbrain

The inferior colliculus (IC) represents a crucial relay station in the auditory pathway, located in the midbrain's tectum and primarily projecting to the thalamus. Despite the identification of distinct cell classes based on various biomarkers in the IC, their specific contributions to the organization of auditory tectothalamic pathways have remained poorly understood. In this study, we demonstrate that IC neurons expressing parvalbumin (ICPV+) or somatostatin (ICSOM+) represent two minimally overlapping cell classes throughout the three IC subdivisions in mice of both sexes. Strikingly, regardless of their location within the IC, these neurons predominantly project to the primary and secondary auditory thalamic nuclei, respectively. Cell class-specific input tracing suggested that ICPV+ neurons primarily receive auditory inputs, whereas ICSOM+ neurons receive significantly more inputs from the periaqueductal gray and the superior colliculus (SC), which are sensorimotor regions critically involved in innate behaviors. Furthermore, ICPV+ neurons exhibit significant heterogeneity in both intrinsic electrophysiological properties and presynaptic terminal size compared with ICSOM+ neurons. Notably, approximately one-quarter of ICPV+ neurons are inhibitory neurons, whereas all ICSOM+ neurons are excitatory neurons. Collectively, our findings suggest that parvalbumin and somatostatin expression in the IC can serve as biomarkers for two functionally distinct, parallel tectothalamic pathways. This discovery suggests an alternative way to define tectothalamic pathways and highlights the potential usefulness of Cre mice in understanding the multifaceted roles of the IC at the circuit level.

Extragonadal Germ Cell Tumor with Hepatic Infiltration in a Child: Aberrant Somatostatin Receptors and the Diagnostic Conundrum

Extragonadal germ cell tumors (GCTs) are challenging to diagnose. We present a case of suprarenal GCT, with hepatic infiltration where differential diagnosis included neuroblastoma and hepatoblastoma. The positive positron emission tomography scan further obfuscated the situation. The diagnosis was clinched by fine-needle aspiration cytology and cell block immunohistochemistry.

Effect of vitamin D3 and a stinging nettle extract on the gastric tissue of rats administered with trinitrobenzene sulfonic acid

In this study, the effects of vitamin D3 (Vit. D) and a stinging nettle [Urtica dioica L. (UD)] extract were examined using histopathological and immunohistochemical methods in the stomach tissues of an experimentally created rat model of Crohn's disease (CD). The CD model was created using trinitrobenzene sulfonic acid (TNBS). The animals in the study were divided into control, TNBS, TNBS+Vit. D, and TNBS+UD groups. At the end of the experiment, the animals were euthanised and their stomach tissues were evaluated for necrosis, degeneration, apoptosis, and inflammation. Additionally, an immunohistochemical method was applied to determine the somatostatin (SSTR), aquaporin-1 (AQP-1), caspase-3, and tumour necrosis factor-alpha (TNF-α) immunoreactivity in the gastric tissues. In the evaluations, degenerative and necrotic changes and mononuclear cell infiltration areas were observed in the TNBS group, but such changes could be improved with Vit. D and UD applications. The results suggest that the combination of the Vit. D and UD extract may have a protective and therapeutic role in mitigating TNBS-induced damage to the gastric tissues, potentially through the regulation of SSTR, AQP-1, caspase-3, and TNF-α expression. This indicates a promising avenue for further research and the exploration of these compounds in the context of gastrointestinal health.

Recalcitrant Hypocalcemia: Postsurgical Hypoparathyroidism Exacerbated by a Chyle Leak Treated With Octreotide

Background/Objective

To report a case of recalcitrant post-surgical hypocalcemia caused by hypoparathyroidism complicated by a chyle leak and octreotide use.

Case Report

A man in his 60s with a 4-month history of voice changes, 10-pound weight loss, and a right-sided neck mass presented with difficulty breathing for 1 week. He had a right laryngeal/hypopharyngeal mass, which was biopsied. Pathology results were positive for invasive squamous cell carcinoma. He underwent an extensive neck surgery, including total thyroidectomy. Postsurgical laboratory results revealed serum corrected calcium of 7.6 mg/dL (ref 8.0-10.2 mg/dL) and parathyroid hormone <6.3 pg/mL (ref. 10-65). Despite treatment with calcium carbonate 12 g (elemental) daily, calcitriol and hydrochlorothiazide, his corrected serum calcium levels remained low. Patient also had a chyle leak that was treated with octreotide. Resolution of his hypocalcemia occurred after substitution of calcium carbonate with calcium citrate, cessation of octreotide, and management of the chyle leak.

Discussion

Our patient likely developed recalcitrant hypocalcemia from: 1) postsurgical hypoparathyroidism, 2) a chyle leak, and 3) the use of octreotide. Administration of octreotide to seal the chyle leak most likely decreased gastric acid production and contributed to decrease in absorption of calcium carbonate. Oral calcium citrate may be better absorbed in this case.

Conclusion

Postsurgical hypoparathyroidism can lead to hypocalcemia. This case is unique in that the patient's chyle leak and the use of octreotide contributed to recalcitrant hypocalcemia.

TRPV1-positive sensory nerves and neuropeptides are involved in epidermal barrier repair after tape stripping in mice

BACKGROUND

The integumentary system of the skin serves as an exceptional protective barrier, with the stratum corneum situated at the forefront. This outermost layer is composed of keratinocytes that biosynthesize filaggrin (encoded by the gene Flg), a pivotal constituent in maintaining skin health. Nevertheless, the precise role of sensory nerves in restoration of the skin barrier after tape stripping-induced epidermal disruption, in contrast to the wound-healing process, remains a tantalizing enigma.

OBJECTIVE

This study aimed to elucidate the cryptic role of sensory nerves in repair of the epidermal barrier following tape stripping-induced disruption.

METHODS

Through the implementation of resiniferatoxin (RTX)-treated denervation mouse model, we investigated the kinetics of barrier repair after tape stripping and performed immunophenotyping and gene expression analysis in the skin or dorsal root ganglia (DRG) to identify potential neuropeptides. Furthermore, we assessed the functional impact of candidates on the recovery of murine keratinocytes and RTX-treated mice.

RESULTS

Ablation of TRPV1-positive sensory nerve attenuated skin barrier recovery and sustained subcutaneous inflammation, coupled with elevated IL-6 level in ear homogenates after tape stripping. Expression of the keratinocyte differentiation marker Flg in the ear skin of RTX-treated mice was decreased compared with that in control mice. Through neuropeptide screening, we found that the downregulation of Flg by IL-6 was counteracted by somatostatin or octreotide (a chemically stable somatostatin analog). Furthermore, RTX-treated mice given octreotide exhibited a partial improvement in barrier recovery after tape stripping.

CONCLUSION

Sensory neurons expressing TRPV1 play an indispensable role in restoring barrier function following epidermal injury. Our findings suggest the potential involvement of somatostatin in restoring epidermal repair after skin injury.

Disinhibition by VIP interneurons is orthogonal to cross-modal attentional modulation in primary visual cortex

Attentional modulation of sensory processing is a key feature of cognition; however, its neural circuit basis is poorly understood. A candidate mechanism is the disinhibition of pyramidal cells through vasoactive intestinal peptide (VIP) and somatostatin (SOM)-positive interneurons. However, the interaction of attentional modulation and VIP-SOM disinhibition has never been directly tested. We used all-optical methods to bi-directionally manipulate VIP interneuron activity as mice performed a cross-modal attention-switching task. We measured the activities of VIP, SOM, and parvalbumin (PV)-positive interneurons and pyramidal neurons identified in the same tissue and found that although activity in all cell classes was modulated by both attention and VIP manipulation, their effects were orthogonal. Attention and VIP-SOM disinhibition relied on distinct patterns of changes in activity and reorganization of interactions between inhibitory and excitatory cells. Circuit modeling revealed a precise network architecture consistent with multiplexing strong yet non-interacting modulations in the same neural population.

Cortical somatostatin long-range projection neurons and interneurons exhibit divergent developmental trajectories

The mammalian cerebral cortex contains an extraordinary diversity of cell types that emerge by implementing different developmental programs. Delineating when and how cellular diversification occurs is particularly challenging for cortical inhibitory neurons because they represent a small proportion of all cortical cells and have a protracted development. Here, we combine single-cell RNA sequencing and spatial transcriptomics to characterize the emergence of neuronal diversity among somatostatin-expressing (SST+) cells in mice. We found that SST+ inhibitory neurons segregate during embryonic stages into long-range projection (LRP) neurons and two types of interneurons, Martinotti cells and non-Martinotti cells, following distinct developmental trajectories. Two main subtypes of LRP neurons and several subtypes of interneurons are readily distinguishable in the embryo, although interneuron diversity is likely refined during early postnatal life. Our results suggest that the timing for cellular diversification is unique for different subtypes of SST+ neurons and particularly divergent for LRP neurons and interneurons.

Prolactin Mediates Long-Term, Seasonal Rheostatic Regulation of Body Mass in Female Mammals

A series of well-described anabolic and catabolic neuropeptides are known to provide short-term, homeostatic control of energy balance. The mechanisms that govern long-term, rheostatic control of regulated changes in energy balance are less well characterized. Using the robust and repeatable seasonal changes in body mass observed in Siberian hamsters, this report examined the role of prolactin in providing long-term rheostatic control of body mass and photoinduced changes in organ mass (ie, kidney, brown adipose tissue, uterine, and spleen). Endogenous circannual interval timing was observed after 4 months in a short photoperiod, indicated by a significant increase in body mass and prolactin mRNA expression in the pituitary gland. There was an inverse relationship between body mass and the expression of somatostatin (Sst) and cocaine- and amphetamine-regulated transcript (Cart). Pharmacological inhibition of prolactin release (via bromocriptine injection), reduced body mass of animals maintained in long photoperiods to winter-short photoperiod levels and was associated with a significant increase in hypothalamic Cart expression. Administration of ovine prolactin significantly increased body mass 24 hours after a single injection and the effect persisted after 3 consecutive daily injections. The data indicate that prolactin has pleiotropic effects on homeostatic sensors of energy balance (ie, Cart) and physiological effectors (ie, kidney, BAT). We propose that prolactin release from the pituitary gland acts as an output signal of the hypothalamic rheostat controller to regulate adaptive changes in body mass.

Simultaneous interneuron labeling reveals population-level interactions among parvalbumin, somatostatin, and pyramidal neurons in cortex

Cortical interneurons shape network activity in cell type-specific ways, and are also influenced by interactions with other cell types. These specific cell-type interactions are understudied, as transgenic labeling methods typically restrict labeling to one neuron type at a time. Although recent methods have enabled post-hoc identification of cell types, these are not available to many labs. Here, we present a method to distinguish between two red fluorophores in vivo, which allowed imaging of activity in somatostatin (SOM), parvalbumin (PV), and putative pyramidal neurons (PYR) in mouse association cortex. We compared population events of elevated activity and observed that the PYR network state corresponded to the ratio between mean SOM and PV neuron activity, demonstrating the importance of simultaneous labeling to explain dynamics. These results extend previous findings in sensory cortex, as activity became sparser and less correlated when the ratio between SOM and PV activity was high.

Increase in NREM sleep slow waves following injections of sodium oxybate in the mouse cerebral cortex and the role of somatostatin-positive interneurons

The systemic administration of sodium oxybate (SXB), the sodium salt of gamma-hydroxybutyric acid, promotes slow wave activity (SWA, 0.5-4 Hz EEG power) and increases non-rapid eye movement (NREM) sleep. These effects are mediated by the widely expressed GABAb receptors, and thus, the brain areas targeted by SXB remain unclear. Because slow waves are mainly a cortical phenomenon, we tested here whether systemic SXB promotes SWA by acting directly on the cortex. Moreover, because somatostatin (SOM) + cortical interneurons play a key role in SWA generation, we also assessed their contribution to the effects of SXB. In adult SOM-Cre mice, the injection of SXB in left secondary motor cortex increased SWA during NREM sleep in the first 30 min post-injection (11 mice: either sex). SWA, the amplitude and frequency of the slow waves, and the frequency of the OFF periods increased ipsilaterally and contralaterally to the SXB injection in frontal and parietal cortex. All these changes disappeared when the intracortical injection of SXB was preceded by the chemogenetic inhibition of the SOM+ cells. Thus, SXB may promote the slow waves of NREM sleep, at least in part, by acting directly on the cortex, and this effect involves GABAergic SOM+ interneurons. Our working hypothesis is that SXB potentiates the ability of these cells to inhibit all other cortical cell types via a GABAb mechanism, thus promoting the transition from ON to OFF periods during NREM sleep.

Pharmacologic inhibition of somatostatin receptor 2 to restore glucagon counterregulation in diabetes

Glucose homeostasis is primarily maintained by pancreatic hormones, insulin and glucagon, with an emerging role for a third islet hormone, somatostatin, in regulating insulin and glucagon responses. Under healthy conditions, somatostatin secreted from pancreatic islet δ-cells inhibits both insulin and glucagon release through somatostatin receptor- induced cAMP-mediated downregulation and paracrine inhibition of β- and α-cells, respectively. Since glucagon is the body's most important anti-hypoglycemic hormone, and because glucagon counterregulation to hypoglycemia is lost in diabetes, the study of somatostatin biology has led to new investigational medications now in development that may help to restore glucagon counterregulation in type 1 diabetes. This review highlights the normal regulatory role of pancreatic somatostatin signaling in healthy islet function and how the inhibition of somatostatin receptor signaling in pancreatic α-cells may restore normal glucagon counterregulation in diabetes mellitus.

Combined Lanreotide Autogel and Temozolomide Treatment of Progressive Pancreatic and Intestinal Neuroendocrine Tumors: The Phase II SONNET Study

BACKGROUND

In advanced neuroendocrine tumors (NET), antiproliferative treatment options beyond somatostatin analogs remain limited. Temozolomide (TMZ) has shown efficacy in NET alone or combined with other drugs.

MATERIALS AND METHODS

SONNET (NCT02231762) was an open, multicenter, prospective, phase II study to evaluate lanreotide autogel 120 mg (LAN) plus TMZ in patients with progressive advanced/metastatic grade 1/2 gastroenteropancreatic (GEP) NET or of unknown primary. Patients could be enrolled at first-line or higher therapy line. The primary endpoint was disease control rate ([DCR], rate of stable disease [SD], partial [PR], and complete response [CR]) at 6 months of LAN and TMZ. Patients with nonfunctioning (NF) NET without progression at 6 months were randomized to 6-month LAN maintenance or watch and wait, patients with functioning (F)-NET with clinical benefit (PR, SD) continued on LAN.

RESULTS

Fifty-seven patients were recruited. The majority of patients received the study drug at second or higher treatment line and had an NET G2. DCR at 6 months LAN and TMZ was 73.5%. After 6 months of further LAN maintenance, 54.5% of patients with F-NET and 71.4% with NF-NET had SD or PR vs 41.7% with NF-NET on observation only. LAN and TMZ were effective in all subgroups analyzed. At 12 months of follow-up, median progression-free survival was 11.1 months. Median serum chromogranin A decreased except in NF-NET on observation. O6-methylguanine DNA methyltransferase promoter methylation appeared to better reflect TMZ response than loss of gene expression. During combination therapy, the most frequent treatment-emergent adverse events grade 3/4 reported were nausea (14%), thrombocytopenia (12.3%), and neutropenia (8.8%). Four deaths were reported resulting from severe adverse events not considered related to study medication.

CONCLUSIONS

LAN plus TMZ is a treatment option for patients with progressive GEP-NET with more aggressive biological profile showing a manageable safety profile.

A novel somatostatin receptor ligand for human ACTH - and GH -secreting pituitary adenomas

OBJECTIVE

Somatostatin receptor ligands have come to play a pivotal role in the treatment of both ACTH- and GH-secreting pituitary adenomas. Clinical efficacy averages 30-50%, thus a considerable number of patients with Cushing's disease or acromegaly remain unresponsive to this therapeutic approach. HTL0030310 is a new somatostatin receptor ligand selective for subtype 5 over subtype 2, thus with a different receptor profile compared to clinical somatostatin receptor ligands.

DESIGN

Assessment of the effect of HTL0030310 on hormone secretion in human ACTH- and GH-secreting pituitary adenomas in vitro.

METHODS

Primary cultures from 3 ACTH-secreting and 5 GH-secreting pituitary adenomas were treated with 1, 10 and 100 nM HTL0030310 alone or with 10 nM CRH or GHRH, respectively. Parallel incubations with 10 nM pasireotide were also carried out. ACTH and GH secretion were assessed after 4 and 24 hour incubation; SSTR2, SSTR3, SSTR5, GH and POMC expression were evaluated after 24 hours.

RESULTS

HTL0030310 reduced unchallenged ACTH and POMC levels up to 50% in 2 ACTH-secreting adenomas and blunted CRH-stimulated ACTH/POMC by 20-70% in all 3 specimens. A reduction in spontaneous GH secretion was observed in 4 GH-secreting adenomas and in 2 specimens during GHRH co-incubation. SSTRs expression was detected in all specimens.

CONCLUSIONS

This first study on a novel somatostatin receptor 5-preferring ligand indicates that HTL0030310 can inhibit hormonal secretion in human ACTH- and GH-secreting pituitary adenomas. These findings suggest a potential new avenue for somatostatin ligands in the treatment of Cushing's disease and acromegaly.

Paracrine signalling by pancreatic δ cells determines the glycaemic set point in mice

While pancreatic β and α cells are considered the main drivers of blood glucose homeostasis through insulin and glucagon secretion, the contribution of δ cells and somatostatin (SST) secretion to glucose homeostasis remains unresolved. Here we provide a quantitative assessment of the physiological contribution of δ cells to the glycaemic set point in mice. Employing three orthogonal mouse models to remove SST signalling within the pancreas or transplanted islets, we demonstrate that ablating δ cells or SST leads to a sustained decrease in the glycaemic set point. This reduction coincides with a decreased glucose threshold for insulin response from β cells, leading to increased insulin secretion to the same glucose challenge. Our data demonstrate that β cells are sufficient to maintain stable glycaemia and reveal that the physiological role of δ cells is to provide tonic feedback inhibition that reduces the β cell glucose threshold and consequently lowers the glycaemic set point in vivo.

Diffuse traumatic brain injury substantially alters plasma growth hormone in the juvenile rat

Traumatic brain injury (TBI) can damage the hypothalamus and cause improper activation of the growth hormone (GH) axis, leading to growth hormone deficiency (GHD). GHD is one of the most prevalent endocrinopathies following TBI in adults; however, the extent to which GHD affects juveniles remains understudied. We used postnatal day 17 rats (n = 83), which model the late infantile/toddler period, and assessed body weights, GH levels, and number of hypothalamic somatostatin neurons at acute (1, 7 days post injury (DPI)) and chronic (18, 25, 43 DPI) time points. We hypothesized that diffuse TBI would alter circulating GH levels because of damage to the hypothalamus, specifically somatostatin neurons. Data were analyzed with generalized linear and mixed effects models with fixed effects interactions between the injury and time. Despite similar growth rates over time with age, TBI rats weighed less than shams at 18 DPI (postnatal day 35; P = 0.03, standardized effect size [d] = 1.24), which is around the onset of puberty. Compared to shams, GH levels were lower in the TBI group during the acute period (P = 0.196; d = 12.3) but higher in the TBI group during the chronic period (P = 0.10; d = 52.1). Although not statistically significant, TBI-induced differences in GH had large standardized effect sizes, indicating biological significance. The mean number of hypothalamic somatostatin neurons (an inhibitor of GH) positively predicted GH levels in the hypothalamus but did not predict GH levels in the somatosensory cortex. Understanding TBI-induced alterations in the GH axis may identify therapeutic targets to improve the quality of life of pediatric survivors of TBI.

Somatostatin affects GnRH neuronal development and migration and stimulates olfactory-related fiber fasciculation

Transient expression of somatostatin (SST) has been observed in the olfactory epithelium (OE) and nerves of chick embryos. Intense expression of SST in these regions on embryonic days (E) 5-8 coincides with the migration of neurons producing gonadotropin-releasing hormone (GnRH) from the OE to the forebrain (FB), suggesting that SST plays a role in the development of GnRH neurons. Using in ovo electroporation of small interfering RNA, we found that the suppression of SST mRNA in the olfactory placode (OP) of E3.5 chick embryos significantly reduced the number of GnRH and Islet-1-immunoreactive neurons in the nasal region without affecting the entry of GnRH neurons into the FB at E5.5-6. SST knockdown did not lead to changes in the number of apoptotic, proliferating, or HuC/D-positive neuronal cells in the OE; therefore, it is possible that SST is involved in the neurogenesis/differentiation of GnRH neurons and OP-derived GnRH-negative migratory neurons. In whole OP explant cultures, we also found that SST or its analog octreotide treatment significantly increased the number of migratory GnRH neurons and the migratory distance from the explants. The co-application of an SST antagonist blocked the octreotide-induced increase in the number of GnRH neurons. Furthermore, the fasciculation of polysialylated neural cell adhesion molecule-immunoreactive fibers emerging from the explants was dependent on octreotide. Taken together, our results provide evidence that SST exerts facilitatory effects on the development of neurons expressing GnRH or Islet-1 and on GnRH neuronal migration, in addition to olfactory-related fiber fasciculation.

Non-Surgical Interventions for the Prevention of Clinically Relevant Postoperative Pancreatic Fistula-A Narrative Review

Clinically relevant postoperative pancreatic fistula (CR-POPF) is the leading cause of morbidity and mortality after pancreatic surgery. Post-pancreatectomy acute pancreatitis (PPAP) has been increasingly understood as a precursor and exacerbator of CR-POPF. No longer believed to be the consequence of surgical technique, the solution to preventing CR-POPF may lie instead in non-surgical, mainly pharmacological interventions. Five databases were searched, identifying eight pharmacological preventative strategies, including neoadjuvant therapy, somatostatin and its analogues, antibiotics, analgesia, corticosteroids, protease inhibitors, miscellaneous interventions with few reports, and combination strategies. Two further non-surgical interventions studied were nutrition and fluids. New potential interventions were also identified from related surgical and experimental contexts. Given the varied efficacy reported for these interventions, numerous opportunities for clarifying this heterogeneity remain. By reducing CR-POPF, patients may avoid morbid sequelae, experience shorter hospital stays, and ensure timely delivery of adjuvant therapy, overall aiding survival where prognosis, particularly in pancreatic cancer patients, is poor.

Therapeutic effects of Bombax ceiba flower aqueous extracts against loperamide-induced constipation in mice

CONTEXT

Bombax ceiba Linnaeus (Bombacaceae) is known as silk cotton tree, the flowers of which are used in many medicinal applications.

OBJECTIVE

To investigate the therapeutic effect of B. ceiba flower aqueous extracts (BCE) against loperamide-induced constipation and characterize the chemical composition of BCE.

MATERIALS AND METHODS

Sixty male Kunming mice were divided into control (saline), model (10 mg/kg loperamide + saline), phenolphthalein (10 mg/kg loperamide + 10 mg/kg phenolphthalein) and different dosage of BCE (10 mg/kg loperamide + 40, 80 and 160 mg/kg BCE, respectively) groups, and received intragastric administrations for eight days. Faecal water content, number of faeces, first black-stool defecation time and gastrointestinal transit rates were evaluated. Various biochemical and molecular biomarkers were assessed in blood and colon. UPLC-ESI-QTOF-MS/MS was used to tentatively identify the composition of the BCE.

RESULTS

BCE treatment (160 mg/kg) could increase faecal water (15.75%), faeces number (11.65%), gastrointestinal transit rate (25.37%) and decrease first black-stool defecation time (24.04%). The BCE (80 mg/kg) increased the serum level of motilin (30.62%), gastrin (54.46%) and substance P (18.99%), and decreased somatostatin (19.47%). Additionally, the BCE (160 mg/kg) reduced the mucosal damage, restored colonic goblet cell function, down-regulated the protein expression of AQP₃ (33.60%) and increased c-kit protein expression (11.63%). Twelve known compounds, including protocatechuic acid, chlorogenic acid and rutin, previously reported in B. ceiba, were identified in the BCE.

DISCUSSION AND CONCLUSIONS

This study suggested that BCE is a promising agent for the treatment of constipation.

Somatostatin Inhibited the EMT of Pancreatic Cancer Cells by Mediating the TGF-β/Smad Signaling Pathway

BACKGROUND

Pancreatic cancer (PC), a commonly recognized malignancy, arises within the digestive tract. Somatostatin (SOM) is a regulatory peptide that acts on secretion in vivo. Several studies have shown that SOM has inhibitory effects on various cancers. This work aims to probe the inhibitory effect, and mechanism of SOM action, on the epithelial-mesenchymal transition (EMT) of PC cells.

METHODS

First, the effects of SOM and transforming growth factor-β (TGF-β) on the proliferation of PC cells was determined by Cell Counting Kit-8 (CCK-8) assay. Next, we assessed the impact of SOM and TGF-β on the metastasis and apoptosis of PC cells using transwell assays and flow cytometry. Finally, we evaluated the effects of SOM and TGF-β on the expression of EMT-related proteins, apoptosis-related proteins, and proteins related to the TGF-β/Smad signaling pathway in PC cells using western blot analysis.

RESULTS

SOM suppressed the growth and metastasis of PC cells, and facilitated their apoptosis (p < 0.05). Moreover, SOM reversed pro-apoptotic effects of TGF-β (p < 0.05). Specifically, SOM increased the expression of Cysteine-aspartic acid protease 3 (Caspase-3) and Bcl-2-associated X protein (Bax) proteins while reducing the expression of B-cell lymphoma 2 (Bcl-2) protein (p < 0.05). SOM also reversed the TGF-β-induced EMT process. The TGF-β1, Smad2, and Smad3 proteins in PC cells treated with SOM were significantly down-regulated (p < 0.05).

CONCLUSIONS

SOM suppressed the EMT progression in PC cells through its regulation of the TGF-β/Smad signaling pathway.

MPOWERED Trial Open-Label Extension: Long-term Efficacy and Safety Data for Oral Octreotide Capsules in Acromegaly

CONTEXT

The MPOWERED core trial (NCT02685709) and open-label extension (OLE) phase investigated long-term efficacy and safety of oral octreotide capsules (OOC) in patients with acromegaly. Core trial primary endpoint data demonstrated noninferiority to injectable somatostatin receptor ligands (iSRLs). Core trial completers were invited to participate in the OLE phase.

OBJECTIVE

To assess long-term efficacy and safety of OOC in patients with acromegaly who previously responded to and tolerated both OOC and injectable octreotide/lanreotide and completed the core phase.

METHODS

The unique study design of transitioning between OOC and iSRLs allowed within-patient evaluations. The proportion of biochemical responders (insulin-like growth factor I < 1.3 × upper limit of normal) at end of each extension year who entered that year as responders was the main outcome measure.

RESULTS

At year 1 extension end, 52/58 patients from both the monotherapy and the combination therapy groups were responders (89.7%; 95% CI 78.8-96.1), 36/41 (87.8%; 95% CI 73.8-95.9) in year 2, and 29/31 (93.5%; 95% CI 78.6-99.2) in year 3. No new or unexpected safety signals were detected; 1 patient withdrew owing to treatment failure. Patients who transitioned from iSRLs in the core trial to OOC in the OLE phase reported improved treatment convenience/satisfaction and symptom control.

CONCLUSION

Patient-reported outcome data support for the first time that transitioning patients randomized to iSRL (who previously responded to both OOC and iSRLs) back to OOC had a significant effect on patients' symptoms score in a prospective cohort. The MPOWERED OLE showed long-term maintenance of response and sustained safety with OOC.

Immunohistochemical evaluation of hormones secreted by pancreatic endocrine tumors

The endocrine component of the pancreas is located primarily in the islets of Langerhans, but is also found as single cells among the acinar cells and duct epithelium. It currently is thought that endocrine tumors of the pancreas (PETs) arise from pluripotent stem cells located within the ductal epithelium rather than from existing endocrine cells. Islet cell components include alpha, beta, PP, delta and epsilon cells, which secrete glucagon, insulin, pancreatic polypeptide, somatostatin and ghrelin, respectively. We investigated immunohistochemical labeling of 24 formalin fixed paraffin embedded PETs to identify which hormones were produced most frequently. Glucagon was the most frequently secreted hormone (83%) in PETS followed by insulin, ghrelin, pancreatic polypeptide and somatostatin.

Inhibitory neuron map of sevoflurane induced neurotoxicity model in young primates

Introduction

Sevoflurane, one of the most commonly used anesthetic agents in children, may induce neuronal dysfunction and cognitive impairment. Exposure to sevoflurane might induce an imbalance between neural excitation and inhibition which could be a mechanism behind anesthesia-induced cognitive and affective dysfunctions. However, the underlying mechanisms remain unclear.

Methods

In this study, we used two rhesus macaques in the control group, and one rhesus macaques in the anesthesia group. We employed single-nucleus RNA sequencing (snRNA-seq) technology to explore alterations in distinct types of inhibitory neurons involved in the long-term cognitive impairment caused by sevoflurane in young macaques.

Results

Following sevoflurane treatment, an upregulation was observed in the SST+ inhibitory neuron in the LHX6+ neighborhood in the hippocampus of rhesus macaques. This alteration might impact brain development by influencing interneuron migration and maturation. Additionally, we proposed a novel classification of inhibitory neurons, defined by CNR1 and LHX6 applicable to both humans and macaques.

Discussion

Our study proposed a novel classification of inhibitory neurons defined by LHX6 and CNR1, relevant in macaques and humans. We also provide evidence that sevoflurane upregulated the SST+ inhibitory neuron in the LHX6+ neighborhood in the hippocampus of rhesus macaques, which may underlie the potential neurotoxic effects induced by general anesthetics. Our results also offer a more reliable approach for studying the structure and function of the human brain.

Growth Axis Somatostatin, Growth Hormone Receptor, and Insulin-like Growth Factor-1 Genes Express and Are Affected by the Injection of Exogenous Growth Hormone in Chinemys reevesii

In this study, to explore the effect of growth hormone changes on the related genes and regulatory roles of the turtle, PCR amplification, real-time fluorescence quantitative analysis, and enzyme cutting technology were used to clone and sequence the somatostatin (SS) gene, growth hormone receptor (GHR), and insulin-like growth factor-1 (IGF-I) sequence of Chinemys reevesii. The effects of human growth hormone on the mRNA expression of growth-axis-related genes SS, GHR, and IGF-1 in different sexes were observed. The study of the SS gene in turtles using real-time fluorescence quantitative PCR showed that the SS gene was mainly expressed in the nervous system and the digestive system, with the highest expression found in the brain, while the GHR gene and the IGF-I gene were expressed in all tissues of Chinemys reevesii. The SS gene was expressed in the brain, pituitary, liver, stomach, and intestine, with the highest expression in the brain and the lowest expression in the liver. Within 4 weeks of the injection of exogenous growth hormone, the expression level of the SS gene in the brain of both sexes first increased and then decreased, showing a parabolic trend, and the expression level of the experimental group was lower than that of the control group. After the injection of growth hormone (GH), the expression of the GHR gene in the liver of both sexes showed a significant increase in the first week, decreasing to the control group level in the second week, and then gradually increasing. Finally, a significant level of difference in the expression of the GHR gene was reached at 3 and 4 weeks. In terms of the IGF-I gene, the changing trend of the expression level in the liver was the same as that of the GHR gene. After the injection of exogenous growth hormone, although the expression of the SS gene increased the inhibition of the secretion of the GHR gene by the Reeves' turtle, exogenous growth hormone could replace the synthesis of GH and GHR, accelerating the growth of the turtle. The experiments showed that the injection of recombinant human growth hormone affects the expression of SS, GHR, and IGF-1 genes, and promotes the growth of the Reeves' turtle.

Mapping alterations in the local synchrony of the cerebral cortex in schizophrenia

BACKGROUND

Observations from different fields of research coincide in indicating that a defective gamma-aminobutyric acid (GABA) interneuron system may be among the primary factors accounting for the varied clinical expression of schizophrenia. GABA interneuron deficiency is locally expressed in the form of neural activity desynchronization. We mapped the functional anatomy of local synchrony in the cerebral cortex in schizophrenia using functional connectivity MRI.

METHODS

Data from 86 patients with schizophrenia and 137 control subjects were obtained from publicly available repositories. Resting-state functional connectivity maps based on Iso-Distant Average Correlation measures across three distances were estimated detailing the local functional structure of the cerebral cortex.

RESULTS

Patients with schizophrenia showed weaker local functional connectivity (i.e., lower MRI signal synchrony) in (i) prefrontal lobe areas, (ii) somatosensory, auditory, visual, and motor cortices, (iii) paralimbic system at the anterior insula and anterior cingulate cortex, and (iv) hippocampus. The distribution of the defect in cortical area synchrony largely coincided with the synchronization effect of the GABA agonist alprazolam previously observed using identical functional connectivity measures. There was also a notable resemblance between the anatomy of our findings and cortical areas showing higher density of parvalbumin (prefrontal lobe and sensory cortices) and somatostatin (anterior insula and anterior cingulate cortex) GABA interneurons in humans.

CONCLUSIONS

Our results thus provide detail of the functional anatomy of synchrony changes in the cerebral cortex in schizophrenia and suggest which elements of the interneuron system are affected. Such information could ultimately be relevant in the search for specific treatments.

Long-term efficacy and safety of subcutaneous pasireotide alone or in combination with cabergoline in Cushing's disease

Objective

This study evaluated short- and long-term efficacy and safety of the second-generation somatostatin receptor ligand pasireotide alone or in combination with dopamine agonist cabergoline in patients with Cushing's disease (CD).

Study design

This is an open-label, multicenter, non-comparative, Phase II study comprising 35-week core phase and an optional extension phase. All patients started with pasireotide, and cabergoline was added if cortisol remained elevated. Eligible patients had active CD, with or without prior surgery, were pasireotide naïve at screening or had discontinued pasireotide for reasons other than safety. Primary endpoint was proportion of patients with a mean urinary free cortisol (mUFC) level not exceeding the upper limit of normal (ULN) at week 35 with missing data imputed using last available post-baseline assessments.

Results

Of 68 patients enrolled, 26 (38.2%) received pasireotide monotherapy and 42 (61.8%) received pasireotide plus cabergoline during the core phase. Thirty-four patients (50.0%; 95% CI 37.6-62.4) achieved the primary endpoint, of whom 17 (50.0%) received pasireotide monotherapy and 17 (50.0%) received combination therapy. Proportion of patients with mUFC control remained stable during the extension phase up to week 99. Treatment with either mono or combination therapy provided sustained improvements in clinical symptoms of hypercortisolism up to week 99. Hyperglycemia and nausea (51.5% each), diarrhea (44.1%) and cholelithiasis (33.8%) were the most frequent adverse events.

Conclusion

Addition of cabergoline in patients with persistently elevated mUFC on maximum tolerated doses of pasireotide is an effective and well-tolerated long-term strategy for enhancing control of hypercortisolism in some CD patients.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT01915303, identifier NCT01915303.

Growth Hormone Action in Somatostatin Neurons Regulates Anxiety and Fear Memory

Dysfunctions in growth hormone (GH) secretion increase the prevalence of anxiety and other neuropsychiatric diseases. GH receptor (GHR) signaling in the amygdala has been associated with fear memory, a key feature of posttraumatic stress disorder. However, it is currently unknown which neuronal population is targeted by GH action to influence the development of neuropsychiatric diseases. Here, we showed that approximately 60% of somatostatin (SST)-expressing neurons in the extended amygdala are directly responsive to GH. GHR ablation in SST-expressing cells (SSTΔGHR mice) caused no alterations in energy or glucose metabolism. Notably, SSTΔGHR male mice exhibited increased anxiety-like behavior in the light-dark box and elevated plus maze tests, whereas SSTΔGHR females showed no changes in anxiety. Using auditory Pavlovian fear conditioning, both male and female SSTΔGHR mice exhibited a significant reduction in fear memory. Conversely, GHR ablation in SST neurons did not affect memory in the novel object recognition test. Gene expression was analyzed in a micro punch comprising the central nucleus of the amygdala (CEA) and basolateral (BLA) complex. GHR ablation in SST neurons caused sex-dependent changes in the expression of factors involved in synaptic plasticity and function. In conclusion, GHR expression in SST neurons is necessary to regulate anxiety in males, but not female mice. GHR ablation in SST neurons also decreases fear memory and affects gene expression in the amygdala, although marked sex differences were observed. Our findings identified for the first time a neurochemically-defined neuronal population responsible for mediating the effects of GH on behavioral aspects associated with neuropsychiatric diseases.SIGNIFICANCE STATEMENT Hormone action in the brain regulates different neurological aspects, affecting the predisposition to neuropsychiatric disorders, like depression, anxiety, and posttraumatic stress disorder. Growth hormone (GH) receptor is widely expressed in the brain, but the exact function of neuronal GH action is not fully understood. Here, we showed that mice lacking the GH receptor in a group of neurons that express the neuropeptide somatostatin exhibit increased anxiety. However, this effect is only observed in male mice. In contrast, the absence of the GH receptor in somatostatin-expressing neurons decreases fear memory, a key feature of posttraumatic stress disorder, in males and females. Thus, our study identified a specific group of neurons in which GH acts to affect the predisposition to neuropsychiatric diseases.

Effects of Somatostatin and Indomethacin Mono or Combination Therapy on High-risk Hyperamylasemia and Post-pancreatitis Endoscopic Retrograde Cholangiopancreatography Patients: A Randomized Study

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) is a minimally invasive technique widely used to diagnose and treat pancreatic and biliary diseases; however, it is linked with imminent hyperamylasemia and post-ERCP pancreatitis (PEP). Somatostatin and indomethacin are the classic recommended drugs used for PEP prevention.

OBJECTIVE

To elucidate the effects of somatostatin and indomethacin mono or in combination to prevent hyperamylasemia and PEP in high-risk individuals.

METHODS

Altogether 1458 patients who underwent ERCP in our hospital from January 2016 to May 2022 were included in this investigation and categorized into 4 groups based on the treatment regimen: placebo, indomethacin, somatostatin, and indomethacin + somatostatin. The pre operation and post operation (at 6, 12, and 24 h) hospitalization cost, length of stay, the occurrence of hyperamylasemia and PEP, levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8, and VAS pain score were determined in the 4 groups. In all the groups, VAS and IL-6, TNF-α, and IL-8 levels substantially increased in the pretreatment and decreased sequentially from 6 to 24 h post operation. The individuals in the indomethacin revealed substantially reduced hyperamylasemia, VAS, and levels of IL-6, TNF-α, and IL-8, 6 h post operation, whereas the hospitalization fee, length of stay, PEP incidence, VAS, levels of IL-6, TNF-α, and IL-8, 12 and 24 h post operation were not statistically important in comparison with the individuals who received placebo therapy. The somatostatin and the indomethacin + somatostatin groups indicated markedly alleviated hospitalization fee, length of stay, the occurrence of hyperamylasemia and PEP, VAS, and the levels of IL-6, TNF-α, and IL-8 at 6, 12, and 24 h post operation compared with the placebo cohort. Furthermore, compared with the indomethacin group, the above-determined factors notably reduced at 6, 12, and 24 h post operation in somatostatin and indomethacin + somatostatin groups. It was also observed that the indomethacin + somatostatin group has substantially decreased the occurrence of hyperamylasemia, VAS score, and levels of IL-6, TNF-α, and IL-8, 6 hours post operation, while at 12 and 24 h post operation, the hospitalization fee, length of stay and incidence of PEP, VAS, levels of IL-6, TNF-α, and IL-8 were not statistically important compared with the somatostatin group. It is also worth noting that the side effects of both drugs are rare and mild.

RESULTS

For high-risk PEP patients, indomethacin and somatostatin can efficiently alleviate post-operative hyperamylasemia and improve their life standard within 6 hours and 24 hours, respectively. Indomethacin is suitable for individuals who underwent simple, short-duration ERCP with expected mild post-operative abdominal pain, whereas somatostatin is given to patients with complicated, long-duration ERCP and expected severe post-operative abdominal pain. Their combinational therapy produces a synergistic effect and can reduce the incidence of hyperamylasemia, thereby improving patients' quality of life within 6 h and is also effective against individuals who received a more complicated, longer-duration ERCP and were expected to have severer and longer post-operative abdominal pain.

Protein Kinase A-Dependent Plasticity of Local Inhibitory Synapses from Hilar Somatostatin-Expressing Neurons

Hippocampal inhibitory neurons (INs) contact local targets and project to different brain areas to form synapses on distal neurons. Despite the importance of INs for hippocampal function and interregional brain communication, the impact of activity-dependent plasticity mechanisms on local and long-range GABAergic synapses formed by hippocampal INs remains to be fully elucidated. Here, we use optogenetic-coupled electrophysiology in mice to show that protein kinase A (PKA), a master regulator of GABAergic synapse plasticity, causes a form of long-term potentiation of inhibitory synapses (iLTP) in hippocampal granule cells (GCs). This form of iLTP is observed in GCs synapses originated in local INs expressing the marker somatostatin (SST), but not in those expressing parvalbumin. Long-range synapses formed by SST INs onto medial septum neurons are unaffected by PKA activation. iLTP of local SST synapses on GCs is accompanied by changes in presynaptic probability of release and is occluded by pharmacological increase of synaptic activity in vivo Our results suggest that PKA-dependent inhibitory synapse plasticity is expressed in local, but not long-range, targets of SST INs and selectively modifies inhibitory microcircuits essential for hippocampal function.

A missense mutation in zinc finger homeobox-3 (ZFHX3) impedes growth and alters metabolism and hypothalamic gene expression in mice

A protein altering variant in the gene encoding zinc finger homeobox-3 (ZFHX3) has recently been associated with lower BMI in a human genome-wide association study. We investigated metabolic parameters in mice harboring a missense mutation in Zfhx3 (Zfhx3Sci/+ ) and looked for altered in situ expression of transcripts that are associated with energy balance in the hypothalamus to understand how ZFHX3 may influence growth and metabolic effects. One-year-old male and female Zfhx3Sci/+ mice weighed less, had shorter body length, lower fat mass, smaller mesenteric fat depots, and lower circulating insulin, leptin, and insulin-like growth factor-1 (IGF1) concentrations than Zfhx3+/+ littermates. In a second cohort of 9-20-week-old males and females, Zfhx3Sci/+ mice ate less than wildtype controls, in proportion to body weight. In a third cohort of female-only Zfhx3Sci/+ and Zfhx3+/+ mice that underwent metabolic phenotyping from 6 to 14 weeks old, Zfhx3Sci/+ mice weighed less and had lower lean mass and energy expenditure, but fat mass did not differ. We detected increased expression of somatostatin and decreased expression of growth hormone-releasing hormone and growth hormone-receptor mRNAs in the arcuate nucleus (ARC). Similarly, ARC expression of orexigenic neuropeptide Y was decreased and ventricular ependymal expression of orphan G protein-coupled receptor Gpr50 was decreased. We demonstrate for the first time an energy balance effect of the Zfhx3Sci mutation, likely by altering expression of key ARC neuropeptides to alter growth, food intake, and energy expenditure.

Ulinastatin combined with somatostatin enhances disease control and modulates serum inflammatory factors in patients with severe pancreatitis

OBJECTIVE

This study was designed to explore the effects of ulinastatin combined with somatostatin on disease control and serum inflammatory factors in patients with severe pancreatitis.

METHODS

The data of 80 patients with severe pancreatitis treated in the First Affiliated Hospital of Jiangxi Medical College from May 2020 to April 2022 were analyzed retrospectively. Among them, 36 patients treated with somatostatin alone (3 mg somatostatin added in 50 mL normal saline) on the basis of standard treatment were assigned to a control group, and the other 44 patients treated with both ulinastatin (100,000 U of ulinastatin injection added in 250 mL 5% glucose solution) and somatostatin (3 mg somatostatin added in 50 mL normal saline) were enrolled into a study group. The levels of serum inflammatory factors (interleukin-1β (IL-1β), interleukin-6 (IL-6), and soluble intercellular adhesion molecule-1 (sICAM-1)), biochemical indexes (C-reactive protein, white blood cell count, and serum amylase) and gastrointestinal function indexes (motilin and gastrin) in the two groups were analyzed and compared before and after treatment. Additionally, the alleviation of clinical symptoms, treatment response and occurrence of adverse reactions were compared between the two groups. The mortality rate of patients within 1 month after the treatment was evaluated, and the risk factors affecting the prognosis were analyzed through logistics regression.

RESULTS

Before treatment, there was no significant difference between the two groups in the levels of IL-1β, IL-6 and sICAM-1 (P>0.05), while after treatment, the levels of all three factors decreased significantly in both groups (P<0.0001), with more notable decreases in the study group than those in the control group (P<0.0001). Before treatment, the two groups were not significantly different in the levels of C-reactive protein, white blood cell count, and serum amylase (P>0.05), while after treatment, all the three levels decreased notably in both groups (P<0.0001), with notably lower levels in the study group than those in the control group (P<0.0001). Before treatment, the levels of motilin and gastrin in the two groups were not significantly different (P>0.05), while after treatment, motilin increased significantly and gastrin decreased significantly in both groups (P<0.0001), and the study group showed a notably higher motilin level and a notably lower gastrin level than the control group (P<0.0001). The study group experienced a significantly earlier disappearance time of abdominal distension and abdominal pain and a significantly shorter hospitalization time than the control group (P<0.0001). Moreover, the study group showed a notably higher overall response rate than the control group (P=0.029), and presented a notably lower incidence of adverse reactions than the control group (P=0.036). According to univariate analysis, age, onset time, Acute Physiology and Chronic Health Evaluation II score and therapeutic regimen were the factors impacting the patients' prognosis. According to logistics regression analysis, therapeutic regimen was an independent risk factor affecting the prognosis.

CONCLUSION

Compared with somatostatin alone, ulinastatin combined with somatostatin is more effective in the treatment of severe pancreatitis. The combination can substantially alleviate the inflammatory response and improve the gastrointestinal function and clinical symptoms of patients, without increasing adverse reactions. Therefore, ulinastatin combined with somatostatin is worthy of clinical promotion.

Cortical somatostatin interneuron subtypes form cell-type-specific circuits

The cardinal classes are a useful simplification of cortical interneuron diversity, but such broad subgroupings gloss over the molecular, morphological, and circuit specificity of interneuron subtypes, most notably among the somatostatin interneuron class. Although there is evidence that this diversity is functionally relevant, the circuit implications of this diversity are unknown. To address this knowledge gap, we designed a series of genetic strategies to target the breadth of somatostatin interneuron subtypes and found that each subtype possesses a unique laminar organization and stereotyped axonal projection pattern. Using these strategies, we examined the afferent and efferent connectivity of three subtypes (two Martinotti and one non-Martinotti) and demonstrated that they possess selective connectivity with intratelecephalic or pyramidal tract neurons. Even when two subtypes targeted the same pyramidal cell type, their synaptic targeting proved selective for particular dendritic compartments. We thus provide evidence that subtypes of somatostatin interneurons form cell-type-specific cortical circuits.

The Role of Genetically Distinct Central Amygdala Neurons in Appetitive and Aversive Responding Assayed with a Novel Dual Valence Operant Conditioning Paradigm

To survive, animals must meet their biological needs while simultaneously avoiding danger. However, the neurobiological basis of appetitive and aversive survival behaviors has historically been studied using separate behavioral tasks. While recent studies in mice have quantified appetitive and aversive conditioned responses simultaneously (Jikomes et al., 2016; Heinz et al., 2017), these tasks required different behavioral responses to each stimulus. As many brain regions involved in survival behavior process stimuli of opposite valence, we developed a paradigm in which mice perform the same response (nose poke) to distinct auditory cues to obtain a rewarding outcome (palatable food) or avoid an aversive outcome (mild footshoock). This design allows for both within-subject and between-subject comparisons as animals respond to appetitive and aversive cues. The central nucleus of the amygdala (CeA) is implicated in the regulation of responses to stimuli of either valence. Considering its role in threat processing (Wilensky et al., 2006; Haubensak et al., 2010) and regulation of incentive salience (Warlow and Berridge, 2021), it is important to examine the contribution of the CeA to mechanisms potentially underlying comorbid dysregulation of avoidance and reward (Sinha, 2008; Bolton et al., 2009). Using this paradigm, we tested the role of two molecularly defined CeA subtypes previously linked to consummatory and defensive behaviors. Significant strain differences in the acquisition and performance of the task were observed. Bidirectional chemogenetic manipulation of CeA somatostatin (SOM) neurons altered motivation for reward and perseveration of reward-seeking responses on avoidance trials. Manipulation of corticotropin-releasing factor neurons (CRF) had no significant effect on food reward consumption, motivation, or task performance. This paradigm will facilitate investigations into the neuronal mechanisms controlling motivated behavior across valences.

From aversive associations to defensive programs: experience-dependent synaptic modifications in the central amygdala

Plasticity elicited by fear conditioning (FC) is thought to support the storage of aversive associative memories. Although work over the past decade has revealed FC-induced plasticity beyond canonical sites in the basolateral complex of the amygdala (BLA), it is not known whether modifications across distributed circuits make equivalent or distinct contributions to aversive memory. Here, we review evidence demonstrating that experience-dependent synaptic plasticity in the central nucleus of the amygdala (CeA) has a circumscribed role in memory expression per se, guiding the selection of defensive programs in response to acquired threats. We argue that the CeA may be a key example of a broader phenomenon by which synaptic plasticity at specific nodes of a distributed network makes a complementary contribution to distinct memory processes.

Development of pancreatic islet cells in the extrahepatic bile ducts of rats with experimentally-induced metabolic syndrome

CONTEXT

There is data about the existence of some endocrine cells in the epithelial layer of the bile duct in humans and rats.

OBJECTIVE

We evaluated Ghrelin-, Insulin-, Glucagon- and Somatostatin-positive cells in peribiliary glands, mast cells, and nerve fibres.

MATERIALS AND METHODS

Wistar rats were used for dietary manipulation with a 15% fructose solution for 12 weeks. Tissue samples were elaborated with immunohistochemistry for Insulin, Glucagon, Ghrelin, and Somatostatin. Glucose and lipid parameters were studied.

RESULTS

In treated animals, Ghrelin+ and Insulin+ cells in perybiliary glands (PBGs) were significantly increased. In the male fructose group there was a significant increase of the homeostasis model assessment insulin resistance (HOMA-IR).

CONCLUSIONS

Stem/progenitor cells in extrahepatic bile tree (EHBT) could be a source of Insulin-producing cells in metabolic syndrome. Fructose treatment induces the increase of Ghrelin+ and Insulin+ cells in PBGs and the elevation of Insulin and Ghrelin plasma concentration.

Treatment of a Severe Form of Euglycemic Ketoacidosis in a Patient Treated with SGLT-2 Inhibitors with the Aid of Somatostatin

Currently, the use of SGLT2 inhibitors is becoming more widespread, both for their role in controlling diabetes, and for their pleiotropic effects on glomerular hyperfiltration and heart failure. Along with their positive effects, these drugs can lead to various complications, the most severe being euglycemic ketoacidosis. The clinical case we have reported precisely describes this potentially serious complication which occurred in a 47-year-old patient who had been on SGLT2 inhibitor therapy for 5 years. In the resolution of this case we used, in addition to standard therapy, the continuous infusion of somatostatin, resulting in a rapid resolution of ketoacidosis and an improvement in the clinical condition.

Predictive Mouse Ultrasonic Vocalization Sequences: Uncovering Behavioral Significance, Auditory Cortex Neuronal Preferences, and Social-Experience-Driven Plasticity

Mouse ultrasonic vocalizations (USVs) contain predictable sequential structures like bird songs and speech. Neural representation of USVs in the mouse primary auditory cortex (Au1) and its plasticity with experience has been largely studied with single-syllables or dyads, without using the predictability in USV sequences. Studies using playback of USV sequences have used randomly selected sequences from numerous possibilities. The current study uses mutual information to obtain context-specific natural sequences (NSeqs) of USV syllables capturing the observed predictability in male USVs in different contexts of social interaction with females. Behavioral and physiological significance of NSeqs over random sequences (RSeqs) lacking predictability were examined. Female mice, never having the social experience of being exposed to males, showed higher selectivity for NSeqs behaviorally and at cellular levels probed by expression of immediate early gene c-fos in Au1. The Au1 supragranular single units also showed higher selectivity to NSeqs over RSeqs. Social-experience-driven plasticity in encoding NSeqs and RSeqs in adult females was probed by examining neural selectivities to the same sequences before and after the above social experience. Single units showed enhanced selectivity for NSeqs over RSeqs after the social experience. Further, using two-photon Ca2+ imaging, we observed social experience-dependent changes in the selectivity of sequences of excitatory and somatostatin-positive inhibitory neurons but not parvalbumin-positive inhibitory neurons of Au1. Using optogenetics, somatostatin-positive neurons were identified as a possible mediator of the observed social-experience-driven plasticity. Our study uncovers the importance of predictive sequences and introduces mouse USVs as a promising model to study context-dependent speech like communications.SIGNIFICANCE STATEMENT Humans need to detect patterns in the sensory world. For instance, speech is meaningful sequences of acoustic tokens easily differentiated from random ordered tokens. The structure derives from the predictability of the tokens. Similarly, mouse vocalization sequences have predictability and undergo context-dependent modulation. Our work investigated whether mice differentiate such informative predictable sequences (NSeqs) of communicative significance from RSeqs at the behavioral, molecular, and neuronal levels. Following a social experience in which NSeqs occur as a crucial component, mouse auditory cortical neurons become more sensitive to differences between NSeqs and RSeqs, although preference for individual tokens is unchanged. Thus, speech-like communication and its dysfunction may be studied in circuit, cellular, and molecular levels in mice.

Somatostatin peptide signaling dampens cortical circuits and promotes exploratory behavior

We sought to characterize the unique role of somatostatin (SST) in the prelimbic (PL) cortex in mice. We performed slice electrophysiology in pyramidal and GABAergic neurons to characterize the pharmacological mechanism of SST signaling and fiber photometry of GCaMP6f fluorescent calcium signals from SST neurons to characterize the activity profile of SST neurons during exploration of an elevated plus maze (EPM) and open field test (OFT). We used local delivery of a broad SST receptor (SSTR) agonist and antagonist to test causal effects of SST signaling. SSTR activation hyperpolarizes layer 2/3 pyramidal neurons, an effect that is recapitulated with optogenetic stimulation of SST neurons. SST neurons in PL are activated during EPM and OFT exploration, and SSTR agonist administration directly into the PL enhances open arm exploration in the EPM. This work describes a broad ability for SST peptide signaling to modulate microcircuits within the prefrontal cortex and related exploratory behaviors.

Genetically Defined Subtypes of Somatostatin-Containing Cortical Interneurons

Inhibitory interneurons play a crucial role in proper development and function of the mammalian cerebral cortex. Of the different inhibitory subclasses, dendritic-targeting, somatostatin-containing (SOM) interneurons may be the most diverse. Earlier studies used GFP-expressing and recombinase-expressing mouse lines to characterize genetically defined subtypes of SOM interneurons by morphologic, electrophysiological, and neurochemical properties. More recently, large-scale studies classified SOM interneurons into 13 morpho-electric transcriptomic (MET) types. It remains unclear, however, how these various classification schemes relate to each other, and experimental access to MET types has been limited by the scarcity of specific mouse driver lines. To address these issues, we crossed Flp and Cre driver lines with a dual-color intersectional reporter, allowing experimental access to several combinatorially defined SOM subsets. Brains from adult mice of both sexes were retrogradely dye labeled from the pial surface to identify layer 1-projecting neurons and immunostained against several marker proteins, revealing correlations between genetic label, axonal target, and marker protein expression in the same neurons. Lastly, using whole-cell recordings ex vivo, we analyzed and compared electrophysiological properties between different intersectional subsets. We identified two layer 1-targeting subtypes with nonoverlapping marker protein expression and electrophysiological properties, which, together with a previously characterized layer 4-targeting subtype, account for >50% of all layer 5 SOM cells and >40% of all SOM cells, and appear to map onto 5 of the 13 MET types. Genetic access to these subtypes will allow researchers to determine their synaptic inputs and outputs and uncover their roles in cortical computations and animal behavior.

A Rare Case of Hepatic Gastrinoma

Zollinger-Ellison syndrome (ZES) is a rare condition caused by gastrin-secreting neuroendocrine tumors known as gastrinomas. We present a case of hepatic ZES presenting as upper gastrointestinal (GI) bleeding in a 70-year-old female. Initial evaluation revealed the patient to be in severe sepsis with septic shock secondary to a urinary tract infection, and her hospitalization was complicated by hematemesis and melena in the setting of multiple duodenal ulcers. Subsequent investigations, including elevated gastrin levels and a somatostatin receptor scan, confirmed the diagnosis of gastrinoma.

[Spatial and temporal expression pattern of somatostatin receptor 2 in mouse]

Somatostatin (SST) is an inhibitory polypeptide hormone that plays an important role in a variety of biological processes. Somatostatin receptor 2 (SSTR2) is the most widely expressed somatostatin receptor. However, the specific cell types expressing Sstr2 in the tissues have not been investigated. In this study, we detected the expression pattern of SSTR2 protein in mouse at different development stages, including the embryonic 15.5 days and the postnatal 1, 7, 15 days as well as 3 and 6 months, by multicolour immunofluorescence analyses. We found that Sstr2 was expressed in some specific cells types of several tissues, including the neuronal cells and astrocytes in the brain, the mesenchymal cells, the hematopoietic cells, the early hematopoietic stem cells, and the B cells in the bone marrow, the macrophages, the type Ⅱ alveolar epithelial cells, and the airway ciliated cells in the lung, the epithelial cells and the neuronal cells in the intestine, the hair follicle cells, the gastric epithelial cells, the hematopoietic stem cells and the nerve fibre in the spleen, and the tubular epithelial cells in the kidney. This study identified the specific cell types expressing Sstr2 in mouse at different developmental stages, providing new insights into the physiological function of SST and SSTR2 in several cell types.

The Efficacy and Safety of Somatostatin Analog after Axillary Node Dissection in Breast Cancer: A Systematic Review and Meta-analysis

BACKGROUND

Somatostatin analogs are expected to reduce lymphatic leakage. However, whether they can be used after axillary lymphadenectomy is unclear. This study aimed to assess the efficacy and safety of somatostatin analogs in axillary lymphadenectomy for breast cancer patients.

METHODS

We performed a random-effects meta-analysis by searching electronic databases for randomized trials and trial registries until June 2022. The primary outcomes were the volume of drained fluid, the duration of drainage, and seroma incidence. Bias was assessed using the Cochrane Collaboration's tool and the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Six trials (738 participants) and one protocol without results were included. Somatostatin analogs may reduce the volume of drained fluid (mean difference = -22.07 mL, 95% confidence interval [CI] = -42.09 to -2.05; I2 = 56%) while resulting in a slight-to-no difference in the duration of drainage (mean difference = -0.48 days, 95% CI = -1.43 to 0.46; I2 = 87%) and seroma incidence (risk ratio = 0.91, 95% CI = 0.61-1.34; I2 = 55%). The certainty of the evidence was low.

CONCLUSIONS

There was limited evidence supporting somatostatin analogs for lymphorrhea after axillary lymphadenectomy. Multicenter randomized controlled trials are needed to confirm the efficacy and safety of somatostatin analogs after axillary lymphadenectomy.

Increasing adult neurogenesis protects mice from epilepsy

Neurogenesis occurs in the adult brain in the hippocampal dentate gyrus, an area that contains neurons which are vulnerable to insults and injury, such as severe seizures. Previous studies showed that increasing adult neurogenesis reduced neuronal damage after these seizures. Because the damage typically is followed by chronic lifelong seizures (epilepsy), we asked if increasing adult neurogenesis would prevent epilepsy. Adult neurogenesis was selectively increased by deleting the pro-apoptotic gene Bax from Nestin-expressing progenitors. Tamoxifen was administered at 6 weeks of age to conditionally delete Bax in Nestin-CreERT2Baxfl/fl mice. Six weeks after tamoxifen administration, severe seizures (status epilepticus; SE) were induced by injection of the convulsant pilocarpine. Mice with increased adult neurogenesis exhibited fewer chronic seizures. Postictal depression was reduced also. These results were primarily female mice, possibly because they were the more affected by Bax deletion than males, consistent with sex differences in Bax in development. The female mice with enhanced adult neurogenesis also showed less neuronal loss of hilar mossy cells and hilar somatostatin-expressing neurons than wild type females or males, which is notable because these two cell types are implicated in epileptogenesis. The results suggest that increasing adult neurogenesis in the normal adult brain can reduce experimental epilepsy, and the effect shows a striking sex difference. The results are surprising in light of past studies showing that suppressing adult-born neurons can also reduce chronic seizures.

Intrathymic somatotropic circuitry: consequences upon thymus involution

Growth hormone (GH) is a classic pituitary-derived hormone crucial to body growth and metabolism. In the pituitary gland, GH production is stimulated by GH-releasing hormone and inhibited by somatostatin. GH secretion can also be induced by other peptides, such as ghrelin, which interacts with receptors present in somatotropic cells. It is well established that GH acts directly on target cells or indirectly by stimulating the production of insulin-like growth factors (IGFs), particularly IGF-1. Notably, such somatotropic circuitry is also involved in the development and function of immune cells and organs, including the thymus. Interestingly, GH, IGF-1, ghrelin, and somatostatin are expressed in the thymus in the lymphoid and microenvironmental compartments, where they stimulate the secretion of soluble factors and extracellular matrix molecules involved in the general process of intrathymic T-cell development. Clinical trials in which GH was used to treat immunocompromised patients successfully recovered thymic function. Additionally, there is evidence that the reduction in the function of the somatotropic axis is associated with age-related thymus atrophy. Treatment with GH, IGF-1 or ghrelin can restore thymopoiesis of old animals, thus in keeping with a clinical study showing that treatment with GH, associated with metformin and dehydroepiandrosterone, could induce thymus regeneration in healthy aged individuals. In conclusion, the molecules of the somatotrophic axis can be envisioned as potential therapeutic targets for thymus regeneration in age-related or pathological thymus involution.

Pasireotide Versus Octreotide in Preventing Complications After Simultaneous Pancreas-Kidney Transplantation

In elective pancreatic surgery, somatostatin-analogues pasireotide and octreotide are variably used to reduce postoperative complications, but knowledge on their role in pancreas transplantation is limited. This study compared pasireotide and octreotide for their association with complications after simultaneous pancreas-kidney transplantation (SPK). This retrospective study included consecutive patients undergoing SPK's from July 2013 to July 2022. Between July 2013 and April 2020, octreotide was administered 0.1 mg s.c. once daily and between May 2020 and July 2022 pasireotide was administered 0.9 mg twice daily, both until third postoperative day. Complications within 90 days postoperatively were collected, and reoperation rate and Comprehensive Complication index (CCI) ≥ 33.7 (morbidity equal to one reoperation) were used as primary outcomes. Of the 213 patients undergoing SPK, 150 patients received octreotide and 63 pasireotide. Baseline characteristics were comparable. Reoperation rate was 25.3% (n = 38) and 17.5% (n = 11) (p = 0.213) and rate of CCI ≥ 33.7 was 40.7% (n = 61) and 30.2% (n = 19) (p = 0.148) in octreotide and pasireotide groups, respectively. When adjusted with donor BMI, pancreas donor risk index, and donor sex, receiving pasireotide translated into OR 0.49 (95% CI: 0.25-0.96 p = 0.037) for CCI ≥ 33.7. Pasireotide was independently associated with lower postoperative morbidity within 90 days of SPK compared to octreotide.

Fentanyl-induced respiratory depression and locomotor hyperactivity are mediated by µ-opioid receptors expressed in somatostatin-negative neurons

Opioid drugs are widely used as analgesics but cause respiratory depression, a potentially lethal side-effect with overdose, by acting on µ-opioid receptors (MORs) expressed in brainstem regions involved in the control of breathing. Although many brainstem regions have been shown to regulate opioid-induced respiratory depression, the types of neurons involved have not been identified. Somatostatin is a major neuropeptide found in brainstem circuits regulating breathing, but it is unknown whether somatostatin-expressing circuits regulate respiratory depression by opioids. We examined the co-expression of Sst (gene encoding somatostatin) and Oprm1 (gene encoding MORs) mRNAs in brainstem regions involved in respiratory depression. Interestingly, Oprm1 mRNA expression was found in the majority (> 50%) of Sst-expressing cells in the preBötzinger Complex, the nucleus tractus solitarius, the nucleus ambiguus, and the Kölliker-Fuse nucleus. We then compared respiratory responses to fentanyl between wild-type and Oprm1 full knockout mice and found that the lack of MORs prevented respiratory rate depression from occurring. Next, using transgenic knockout mice lacking functional MORs specifically in Sst-expressing cells, we compared respiratory responses to fentanyl between control and the conditional knockout mice. We found that respiratory rate depression by fentanyl was preserved when MORs were deleted only in Sst-expressing cells. Our results show that despite co-expression of Sst and Oprm1 in respiratory circuits and the importance of somatostatin-expressing cells in the regulation of breathing, these cells do not mediate opioid-induced respiratory rate depression. Instead, MORs found in respiratory cell populations other than Sst-expressing cells likely contribute to the respiratory effects of fentanyl.Significance statementOpioid drugs cause respiratory depression, a potentially lethal side-effect with overdose, by acting on µ-opioid receptors in brainstem regions regulating breathing, therefore limiting their effective use as analgesics. Somatostatin is a major neuropeptide found within these brainstem circuits, but it is unknown whether somatostatin circuits regulate respiratory depression by opioids. We found that somatostatin-expressing neurons co-express µ-opioid receptors in respiratory circuits but that respiratory rate depression by fentanyl was preserved despite genetic deletion of µ-opioid receptors in somatostatin-expressing cells. Our results suggest that somatostatin-expressing cells are resistant to the rate-depressive effects of opioids and that other cells contribute to the effects of fentanyl on breathing. Somatostatin-expressing cells may constitute a cell population that can be targeted to stimulate breathing when it fails with opioids.