Amyloid formation in human IAPP transgenic mouse islets and pancreas, and human pancreas, is not associated with endoplasmic reticulum stress

Aims/hypothesis  Supraphysiological levels of the amyloidogenic peptide human islet amyloid polypeptide have been associated with beta cell endoplasmic reticulum (ER) stress. However, in human type 2 diabetes, levels of human IAPP are equivalent or decreased relative to matched controls. Thus, we sought to investigate whether ER stress is induced during amyloidogenesis at physiological levels of human IAPP. Methods  Islets from human IAPP transgenic mice that develop amyloid, and non-transgenic mice that do not, were cultured for up to 7 days in 11.1, 16.7 and 33.3 mmol/l glucose. Pancreases from human IAPP transgenic and non-transgenic mice and humans with or without type 2 diabetes were also evaluated. Amyloid formation was determined histologically. ER stress was determined in islets by quantifying mRNA levels of Bip, Atf4 and Chop (also known as Ddit3) and alternate splicing of Xbp1 mRNA, or in pancreases by immunostaining for immunoglobulin heavy chain-binding protein (BIP), C/EBP homologous protein (CHOP) and X-box binding protein 1 (XBP1). Results  Amyloid formation in human IAPP transgenic islets was associated with reduced beta cell area in a glucose- and time-dependent manner. However, amyloid formation was not associated with significant increases in expression of ER stress markers under any culture condition. Thapsigargin treatment, a positive control, did result in significant ER stress. Amyloid formation in vivo in pancreas samples from human IAPP transgenic mice or humans was not associated with upregulation of ER stress markers. Conclusions/interpretation  Our data suggest that ER stress is not an obligatory pathway mediating the toxic effects of amyloid formation at physiological levels of human IAPP.     

Heat-shock protein 70 acts as an effective adjuvant in neonatal mice and confers protection against challenge with herpes simplex virus

Immunization of the neonate is a highly desirable goal for vaccine developers, since the neonate is profoundly susceptible to a number of viral and bacterial pathogens. The neonatal immune system tends to generate Th2 recall responses, known as neonatal tolerance, which may not protect against viral challenge later in life. In this study we demonstrate that a potent immune proinflammatory stimulator, heat-shock protein 70 (hsp70), can act as an effective and safe adjuvant in neonates. Priming of neonates with hsp70 coupled to a viral MHC Class I-restricted epitope (gB498-505) and injection with recombinant gB generated strong cytotoxic T lymphocyte (CTL) responses and a Th1 primary T helper cell response during the neonatal period. In addition, enhanced CTL and predominant Th1 recall responses to viral antigens were observed following secondary challenge as adults. These responses were sufficient to allow protection against a lethal challenge with Herpes Simplex Virus Type-1 (HSV-1). Therefore, hsp70 in conjunction with viral epitopes and recombinant viral protein can perhaps prime protective immune responses to herpes viruses early in life when infection, which can be life-threatening, and the establishment of latency frequently occur.     

5-HT1B receptors and alpha 2A/2C-adrenoceptors mediate external carotid vasoconstriction to dihydroergotamine

Dihydroergotamine produces external carotid vasoconstriction in vagosympathectomized dogs by 5-HT(1B/1D) receptors and alpha(2)-adrenoceptors. This study identified the specific subtypes involved in this response. One-minute intracarotid infusions of dihydroergotamine (5.6-10 microg/min) dose-dependently decreased external carotid blood flow without affecting blood pressure or heart rate. This response was: (1) partly blocked in dogs pretreated intravenously with the antagonists SB224289 (5-HT(1B); 2,3,6,7-tetrahydro-1'-methyl-5-[2'-methyl-4' (5-methyl-1,2,4-oxadiazol-3-yl)biphenyl-4-carbonyl]furo[2,3-f]indole-3-spiro-4'-piperidine hydrochloride), rauwolscine (alpha(2)), BRL44408 (alpha(2A); 2-[2H-(1-methyl-1,3-dihydroisoindole)methyl]-4,5-dihydroimidazole) or MK912 (alpha(2C); (2S,12bS)-1'3'-dimethylspiro(1,3,4,5',6,6',7,12b-octahydro-2Hbenzo[b]furo[2,3-a]quinazoline)-2,4'-pyrimidin-2'-one); (2) markedly blocked after SB224289 plus rauwolscine; and (3) unaffected after BRL15572 (5-HT(1D); 1-(3-chlorophenyl)-4-[3,3-diphenyl (2-(S,R) hydroxypropanyl) piperazine] hydrochloride) or imiloxan (alpha(2B)). Therefore, the above response involves 5-HT(1B) receptors and alpha(2A/2C)-adrenoceptors.     

Plasma pancreatic polypeptide levels are associated with differences in body fat distribution in human subjects

Aims/hypothesis Pancreatic polypeptide (PP) is produced by the F-cells of the pancreas, and its plasma concentration has been used as a marker of parasympathetic activity. Recent work in rodents suggests that there is both sympathetic and parasympathetic innervation of white adipose tissue and that parasympathetic activity is anabolic resulting in lipid accumulation. We have examined whether in humans increased PP levels are associated with increased intra-abdominal fat (IAF), and thereby insulin resistance. Materials and methods We measured PP levels in 177 non-diabetic subjects (75 male/102 female; age 32–75 years) 3 min after an i.v. glucose bolus during a frequently sampled intravenous glucose tolerance test. IAF and s.c. fat (SCF) areas were measured by CT scan. The insulin sensitivity index (S _I) was quantified using Bergman’s minimal model. Results PP levels were higher in men than in women (96.2 ± 72.2 vs 76.1 ± 55.0 pg/ml, mean ± SD, p = 0.037), as was IAF area (124.7 ± 67.4 vs 83.0 ± 57.7 cm², p < 0.001). While PP levels were significantly associated with IAF (r = 0.16, p = 0.031), WHR (r = 0.30, p < 0.001) and age (r = 0.37, p < 0.01), they were not associated with SCF (r = 0.02, p = 0.829). The association between PP and IAF was not independent of age and/or sex. S _I was negatively associated with PP levels (r = −0.17, p = 0.026) and IAF area (r = −0.65, p < 0.001). The association between S _I and PP disappeared after adjusting for IAF area, indicating that S _I was not a major determinant of PP levels. Conclusions/interpretation In humans, age and sex may modulate the association between plasma PP level and IAF area, suggesting that they may be determinants of parasympathetic activity and thus IAF accumulation.     

Lack of effect of the adenosine A1 receptor agonist, GR79236, on capsaicin-induced CGRP release in anaesthetized pigs

Migraine is a common neurological disorder that is associated with an increase in plasma calcitonin gene-related peptide (CGRP) levels. CGRP, a potent vasodilator released from the activated trigeminal sensory nerves, dilates intracranial blood vessels and transmits vascular nociception. Hence, inhibition of trigeminal CGRP release may prevent neurotransmission and, thereby, ameliorate migraine headache. Therefore, the present study in anaesthetized pigs investigates the effects of a selective adenosine A(1) receptor agonist, GR79236 (3, 10 and 30 microg/kg, i.v.) on capsaicin-induced carotid haemodynamic changes and on plasma CGRP release. Intracarotid (i.c.) infusion of capsaicin (10 microg/kg/min, i.c.) increased the total carotid blood flow and conductance as well as carotid pulsations, but decreased the difference between arterial and jugular venous oxygen saturations. These responses to capsaicin were dose-dependently attenuated by GR79236. However, the increases in the plasma CGRP concentrations by capsaicin remained essentially unmodified after GR79236 treatment. The above results suggest that GR79236 may have an antimigraine potential due to its postjunctional effects (carotid vasoconstriction) rather than to prejunctional inhibition of trigeminal CGRP release.     

In vivo rescue of defective memory CD8+ T cells by cognate helper T cells

The magnitude and efficacy of CD8(+) T cell memory may notably regress, especially if immune induction occurs in the absence of adequate CD4(+) help. This report demonstrates that this CD8(+) memory malfunction could be remedied if a source of cognate antigen-recognizing helper cells were provided during recall. The inability of adoptive transfer of memory SIINFEKL-specific CD8 cells to reject tumors was overcome if recipients were primed for ovalbumin-specific helper cell responses. Additionally, animals primed for a SIINFEKL-specific memory response and incapable of rejecting the tumor could regain protective immunity if given helper cells. This pattern of CD8(+) T cell functional rescue or reprogramming by helper cell transfer was replicated using a Herpes simplex virus antiviral immunity system. Our results could mean that therapeutic vaccine approaches could be designed to compensate situations that have defective CD8(+) T cell function.     

Adverse drug reaction monitoring in a secondary care hospital in South India

Aims

To ascertain the current burden of ADRs at a Government hospital in Ooty and to assess the severity of reported ADRs and the additional financial burden associated with ADRs.

Methods

A prospective, spontaneous reporting study was conducted over a period of 9 months of inpatient admissions to the medical wards, co-ordinated by clinical pharmacists. The WHO definition of an ADR was adopted. The Naranjo algorithm scale was used for causality assessment. Confirmed ADRs were classified according to the Wills & Brown [7] method and assessed for severity and patient outcomes. The average cost incurred in treating the ADRs was calculated.

Results

Of the total of 187 adverse drug events (ADEs) reported, 164 reports from 121 patients were confirmed as ADRs, giving an overall incidence of 9.8%. This included 58 (3.4%) ADR related admissions and 63 (3.7%) ADRs occurring during the hospital stay. About two thirds of the reactions (102, 62.2%) were classified as probable. The majority of the reactions (88, 53.7%) were mild. Most patients (119, 72.6%) recovered from the incidence. The majority of the reactions were of type H (100, 61%) which indicates that they were not predictable and not potentially preventable. An average cost of 481 rupees (£6) was spent on each patient to manage ADRs.

Conclusions

The incidence and severity of ADRs documented in our study are lower than those reported in comparable populations in Western studies but more than those reported in India.

What is already known about this subject

• The benefits of adverse drug reaction (ADR) monitoring are well-known.
• Poor awareness and nonavailability of a central co-ordinating body resulted in lack of ADR monitoring in India.
• The National Pharmacovigilance Programme was recently initiated, encouraging ADR monitoring in selected centres, including our centre.

What this study adds

• This is the first study of its kind at GHQH, Ootacamund that has provided insight into the burden of ADRs here.
• The incidence and severity of ADRs documented in our study is lower than those reported in comparable populations in Western studies but more than those reported in India.