Prevalence of endometriosis in women with systemic lupus erythematosus and Sjögren's syndrome

Endometriosis is associated with a number of immunologic alterations. It has been suggested that autoimmune disorders could be more frequent in patients with endometriosis. The aim of this study is to ascertain whether the prevalence of two well-known autoimmune diseases [systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS)] is increased in women with endometriosis. The clinical charts of four different populations assisted at the same hospital were manually revised: (i) SLE population ( n = 120), (ii) SS ( n = 22), (iii) endometriosis ( n = 342) and (iv) control population ( n = 501 consecutive unselected asymptomatic women). Among SLE women, the prevalence of endometriosis was 1.67% (2/120), similar to the 4.39% prevalence of the control group (22/501), the OR being 0.37 [95%CI 0.09—1.59]. Among SS women, the prevalence of endometriosis was 9.09 (2/22), also similar to the control group OR 2.17 [95%CI 0.48—9.90]. In the same way, when comparing endometriosis cases with asymptomatic women, similar frequencies of SLE (0.58% and 0.2%) and SS were found (0% and 0%). Women with endometriosis do not have an increased prevalence of SLE or SS. Lupus (2007) 16, 736—740.

Non-infectious aortitis: a report of 32 cases from a single tertiary centre in a 4-year period and literature review

OBJECTIVES

Non-infectious aortitis often presents with non-specific symptoms leading to inappropriate diagnostic delay. We intend to describe the clinical spectrum and outcome of patients with aortitis diagnosed at a single centre.

METHODS

We reviewed the clinical charts of patients diagnosed with non-infectious aortitis between January 2010 and December 2013 at the Rheumatology Division from a 1.000-bed tertiary teaching hospital from Northern Spain. The diagnosis of aortitis was usually based on FDG-PET-CT scan, and also occasionally on CT or MRI angiography or helical CT-scan.

RESULTS

During the period of assessment 32 patients (22 women and 10 men; mean age 68 years [range, 45-87]) were diagnosed with aortitis. The median interval from the onset of symptoms to the diagnosis was 21 months. FDG-PET CT scan was the most common tool used for the diagnosis of aortitis. The underlying conditions were the following: giant cell arteritis (n=13 cases); isolated polymyalgia rheumatica (PMR) (n=11); Sjögren's syndrome (n=2), Takayasu arteritis (n= 1); sarcoidosis (n=1), ulcerative colitis (n=1), psoriatic arthritis (n=1), and large-vessel vasculitis that also involved the aorta (n=2). The most common clinical manifestations at diagnosis were: PMR features, often with atypical clinical presentation (n=23 patients, 72%); diffuse lower limb pain (n=16 patients, 50%); constitutional symptoms (n=12 patients, 37%), inflammatory low back pain (n=9 patients, 28%) and fever (n=7 patients, 22%). Acute phase reactants were increased in most cases (median erythrocyte sedimentation rate 46 mm/1st hour, and a median serum C-reactive protein 1.5 mg/dL).

CONCLUSIONS

Aortitis is not an uncommon condition. The diagnosis is often delayed. Atypical PMR features, unexplained low back or limb pain, constitutional symptoms along with increased acute phase reactants should be considered 'red flags' to suspect the presence of aortitis.

Extra-articular disease in patients with spondyloarthritis. Baseline characteristics of the spondyloarthritis cohort of the AQUILES study

OBJECTIVES

To describe the prevalence of extra-articular disease (uveitis, psoriasis and inflammatory bowel disease [IBD]), in a cohort of patients with spondyloarthritis (SpA).

PATIENTS AND METHODS

AQUILES is an observational, prospective and multicentric study of three cohorts of patients with one of the following immune-mediated inflammatory diseases (IMID): SpA, psoriasis, or IBD. In the present cohort, patients ≥18 years of age with SpA were enrolled from Rheumatology clinics. The main objective was to assess the coexistence of these diseases and of uveitis, based on the patients' clinical history up to the study entry.

RESULTS

A total of 601 patients with SpA (men: 63.1%; women: 36.9%) were enrolled. The specific diagnoses were: ankylosing spondylitis (55.1%), psoriatic arthritis (25.1%), undifferentiated spondyloarthritis (16.1%), enteropathic arthritis (2.5%), and others (1.3%). In 43.6% (95% CI: 39.7-47.6) of the patients, at least one of the three abovementioned diseases was encountered, predominantly psoriasis (prevalence 27.8%, 95% CI: 24.4-31.5), uveitis (13.6%, CI 95%: 11.1-16.6) and IBD (5.1%, 95% CI: 3.7-7.2). In patients with ankylosing spondylitis the proportion of other disease was 25.3% (IBD: 3.9%, psoriasis: 5.4%, uveitis: 19.0%) whilst it was 94.7% in psoriatic arthritis, due to the presence of psoriasis (94.0%). The coexistence of these diseases was associated with age, female gender and the presence of other extra-articular manifestations associated with SpA.

CONCLUSIONS

Extra-articular disease in patients with SpA is common and, in this study, it was associated to age, female gender and the presence of other SpA-related extra-articular manifestations.

Tocilizumab in refractory aortitis: study on 16 patients and literature review

OBJECTIVES

Non-infectious aortitis is often refractory to standard immunosuppressive therapy. Since IL-6 has been implicated in the pathogenesis of aortitis, we assessed the efficacy of the anti-IL6 receptor monoconal antibody tocilizumab (TCZ) in a series of patients with refractory non-infectious aortitis.

METHODS

Review of 16 patients (14 women/2 men) with refractory aortitis diagnosed by imaging (CT angiography, MR angiography, and/or PET) that were treated with TCZ.

RESULTS

The mean age±SD was 51.4±20.1 years. The underlying conditions were: Takayasu arteritis (TakA) (n=7 cases), giant cell arteritis (GCA) (n=7), relapsing polychondritis (RP) (n=1), and aortitis associated with retroperitoneal fibrosis (n=1). TCZ was the first biologic drug used in all patients with GCA and in the patient with aortitis associated with retroperitoneal fibrosis but in only 2 of 7 TakA patients. In the remaining cases anti-TNF inhibitors were prescribed before TCZ (standard dose was 8 mg/kg/iv/4 weeks). After a mean±SD follow-up of 11.8±6.6 months most patients experienced clinical improvement, showing reduction of erythrocyte sedimentation rate from 43±36 mm/1st h to 5±4 mm/1st h at last visit. At TCZ onset, 25% of patients had fever and 19% polymyalgia rheumatica. These manifestations disappeared after 3 months of TCZ therapy. A corticosteroid sparing effect was also achieved (from 27.3±17.6 mg/day of prednisone at TCZ onset to 4.2±3.8 mg/day at last visit). TCZ had to be discontinued in a patient because of severe neutropenia.

CONCLUSIONS

TCZ appears to be effective and relatively safe in patients with inflammatory aortitis refractory to corticosteroids or to other biologic immunosuppressive drugs.

Revisiting clinical differences between hypersensitivity vasculitis and Henoch-Schönlein purpura in adults from a defined population

OBJECTIVES

Hypersensitivity vasculitis (HV) and Henoch-Schönlein purpura (HSP) are the most common entities included within the category of cutaneous vasculitis (CV). Palpable purpura and histological changes characterised by the presence of leukocytoclastic vasculitis are common in both conditions. Therefore, considerable overlap between them is often seen. It is especially true when the CV occurs in adults. To further establish clinical differences between these two conditions, in the present study we assessed the main clinical differences between HV and HSP in a wide and unselected series of adults with CV from a defined population.

METHODS

We reviewed the clinical records of 297 consecutive adults (age >20 years) seen at a single centre between January 1975 and December 2012 that were classified as having HSP or HV according to the criteria proposed by Michel et al. (J Rheumatol 1992; 19: 721-8).

RESULTS

Based on the inclusion criteria, 102 adult patients (71 men/31 women) were classified as HSP and 195 (104 men/91 women) as HV. The mean age was similar in both groups (55.8±16.5 years in HSP and 56.8±18.3 years in HV). Precipitating events, usually an upper respiratory tract infection and/or drug intake, were more frequently observed in HV. Both at the beginning of the disease and when the CV was established clinical manifestations were more frequent in patients with HSP than in those with HV. It was the case for gastrointestinal (57.4% vs. 6.8%; p<0.001), joint (51.5% vs. 36.6%; p=0.01) and renal involvement (86.3% vs. 18.3%; p<0.001). Corticosteroid (56.7% vs. 22%; p<0.001) and cytotoxic drug (19.4% vs. 3.2%; p<0.001) use was also more common in patients with HSP. After a median follow-up of 15.5 (interquartile range- IQR; 3-37) months in HSP and 4 (IQR; 2-12) months in HV, the outcome was better in HV than in HSP. In this regard, complete recovery (72.6% vs. 85.4%; p=0.01) was more commonly observed in HV while residual renal involvement (15.3% vs. 4.2%; p<0.001) was more common in HSP. The disease relapsed in 35.3% of patients with HSP and in 24.4% with HV (p=0.07).

CONCLUSIONS

Our results confirm the claim that these two diseases presenting with similar cutaneous involvement are certainly two separate entities with greater systemic involvement and less favourable outcome in HSP.

Henoch-Schönlein purpura in northern Spain: clinical spectrum of the disease in 417 patients from a single center

The severity of clinical features and the outcomes in previous series of patients reported with Henoch-Schönlein purpura (HSP) vary greatly, probably due to selection bias. To establish the actual clinical spectrum of HSP in all age groups using an unselected and wide series of patients diagnosed at a single center, we performed a retrospective review of 417 patients classified as having HSP according to the criteria proposed by Michel et al. Of 417 patients, 240 were male and 177 female, with a median age at the time of disease diagnosis of 7.5 years (interquartile range [IQR], 5.3-20.1 yr). Three-quarters of the patients were children or young people aged 20 years or younger (n = 315), and one-quarter were adults (n = 102). The most frequent precipitating events were a previous infection (38%), usually an upper respiratory tract infection, and/or drug intake (18.5%) shortly before the onset of the vasculitis. At disease onset the most common manifestations were skin lesions (55.9%), nephropathy (24%), gastrointestinal involvement (13.7%), joint symptoms (9.1%), and fever (6.2%). Cutaneous involvement occurring in all patients, mainly purpuric skin lesion, was the most common manifestation when the vasculitis was fully established, followed by gastrointestinal (64.5%), joint (63.1%), and renal involvement (41.2%). The main laboratory findings were leukocytosis (36.7%), anemia (8.9%), and increased serum IgA levels (31.7%). The most frequent therapies used were corticosteroids (35%), nonsteroidal antiinflammatory drugs (14%), and cytotoxic agents (5%). After a median follow-up of 12 months (IQR, 2-38 mo), complete recovery was observed in most cases (n = 346; 83.2%), while persistent, usually mild, nephropathy was observed in only 32 (7.7%) cases. Relapses were observed in almost a third of patients (n = 133; 31.9%).In conclusion, although HSP is a typical vasculitis affecting children and young people, it is not uncommon in adults. The prognosis is favorable in most cases, depending largely on renal involvement.

Henoch-Schönlein purpura nephritis and IgA nephropathy: a comparative clinical study

OBJECTIVES

Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) are related syndromes. In the present study we aimed to compare the clinical characteristics and outcome of a large and unselected series of patients diagnosed as having HSPN and IgAN.

METHODS

Comparative study of a wide and unselected population of HSPN (142 patient) and IgAN (61 patients) from a teaching hospital of Northern Spain.

RESULTS

All of the following comparisons were expressed between HSPN vs. IgAN, respectively. HSPN patients were younger (30.6±26.4 vs. 37.1±16.5 years, p<0.001). Precipitating events, usually an upper respiratory tract infection and/or drug intake, were more frequently observed in HSPN (38% vs. 23%, p=0.03). Extra-renal manifestations were also more common in HSPN than in IgAN; skin lesions (100% vs. 1.8%; p<0.001), gastrointestinal (62% vs. 7.4%; p<0.001), and joint involvement (61.3% vs. 3.6%; p<0.001). However, nephritis was less severe in HSPN, renal insufficiency (25% in HSPN vs. 63.4% in IgAN; p<0.001), nephrotic syndrome (12.5%, vs. 43.7%; p<0.001), and nephritic syndrome (6.8% vs. 10.7%; NS). Leukocytosis was more frequent in HSPN (22.5% vs. 8.2%; p=0.015) and anaemia in IgAN (12.7% in HSPN vs. 36% in IgAN, p<0.001). The frequency of corticosteroid (79.6% vs. 69%; NS) and cytotoxic drug (19% vs. 16.5%, NS) use was similar. The frequency of relapses was similar (38.6% in HSPN vs. 36.3% in IgAN). After a median follow-up of 120.8 (IQR; 110-132) months in HSPN and 138.6 (IQR; 117-156) in IgAN, requirement for dialysis (2.9% vs. 43.5%; p<0.001), renal transplant (0% vs. 36%, p<0.001) and residual chronic renal insufficiency (4.9% vs. 63.8%; p<0.001) was more frequently observed in patients with in IgAN.

CONCLUSIONS

HSPN and IgAN represent different syndromes. IgAN has more severe renal involvement while HSPN is associated with more extra-renal manifestations.

[Investigation of a water-borne Salmonella ohio outbreak]

BACKGROUND

The genus Salmonella is one of the main causes of foodborne and waterborne illness worldwide. It is a major public health concern almost entirely due to S. enteritidis. However, outbreaks caused by Salmonella ohio are rare. We have not found any reference about salmonellosis by S. ohio whose origin was water of a drinking fountain.

METHODS

An epidemiological survey was carried out to investigate the origin of the outbreak, and information was sought on personal details, symptoms, contact with others who had ill as well as a history of eating. Fecal specimens and water samples were cultured for bacterial pathogens including Salmonella. Salmonella isolates obtained were characterized by stereotyping.

RESULTS

A total of 101 persons were exposed. 87 of these were interviewed, but only 59 of these were affected (attack rate: 67.8%), including 56 children and 3 adults. Syndrome was not severe, in general, persisting for a period of 2 days, in average. S. ohio was isolated from the water and from 2 of the 13 stool specimens analysed.

CONCLUSIONS

The outbreak was caused by consumption of water from a drinking fountain which was contaminated by S. ohio. This fountain had not a chlorination system. An outbreak due to S. ohio whose origin is the consumption of water from a drinking fountain is described for the first time in this paper. It can be concluded the importance of keeping a good epidemiological control system to investigate and prevent outbreaks. The control of drinking fountains is also important, to prevent its contamination.

Physical mapping of human insulin-like growth factor-I using specific monoclonal antibodies

The primary structure of recombinant human (h) insulin-like growth factor-I (IGF-I) epitopes recognized by a panel of 28 monoclonal antibodies (mAbs) is characterized. Pairwise mAb epitope mapping defines eight 'epitopic clusters' (I-VIII) which cover nearly the entire solvent-exposed IGF-I surface. Monoclonal antibody reactivity with 32 overlapping synthetic peptides and with IGF-I mutants is used to associate these epitopic clusters with the probable primary IGF-I sequences recognized. Epitopic cluster I involves residues in the C-domain and the first alpha-helix of the A-domain; clusters II, V and VII involve principally the B-domain; clusters III and IV map to amino acid sequences (55-70) and (1-13) respectively; cluster VI includes the A- and B-domains; and cluster VIII involves mainly the C-terminal part of the B-domain. Data indicate that this mAb panel defines 14 distinct IGF-I epitopes. The specific inhibition of HEL 92.1.7 IGF-I-promoted proliferation by these mAbs was explored. Direct correlation between mAb affinity and inhibitory activity was observed except in the case of clusters III- and VIII-specific mAbs. Finally, the combination of epitopic cluster I and II mAbs detect 0.5-10 ng/ml hIGF-I in a sandwich immunoassay, with no IGF-II crossreactivity. These anti-IGF-I mAbs are, therefore, useful for both the inhibition of IGF-I mitogenic activity and for the quantification of this growth factor. The potential use of this mAb panel in tumor cell growth control is discussed.

[Estimation of the use of seat belts: an observational study and a telephone survey]

OBJECTIVE

To estimate the prevalence of safety-belt use in a telephone survey and an observational survey.

PATIENTS AND METHODS

Observational survey. Trained interviewers studied 4,067 front-seat occupants, at ten intersections of Madrid, according to "National Highway Traffic Safety Administration" guidelines. TELEPHONE SURVEY: We selected 433 front seat occupants from the Madrid city residential telephone directory. The questionnaire was completed by trained interviewers.

RESULTS

Prevalence by the observational survey was 58.5%, and was significantly higher at interurban intersections (OR = 2.1) than city intersections. In the telephone survey, the overall prevalence was 94% at interurban area and 64% at city area and it was associated with no history of lines and positive opinion of effectiveness of safety belts.

CONCLUSIONS

The safety belt prevalence observed is low, especially in the urban area. The telephone survey overestimates the safety belt use, but contributes with useful information for planning strategies.

Reversal of the inhibitory effects of calcitonin gene-related peptide (CGRP) and amylin on insulin secretion by the 8-37 fragment of human CGRP

The 8-37 fragment of human calcitonin gene-related peptide [(8-37)hCGRP] antagonizes the effects of calcitonin gene-related peptide (CGRP) and amylin in a number of tissues. We have studied the influence of (8-37)hCGRP on the effects of both CGRP and amylin on insulin secretion. In the perfused rat pancreas, homologous CGRP and amylin, at 75 pM, exerted comparable inhibitory effects on the insulin response to 9 mM glucose (ca. 70%; P < 0.025). These effects were antagonized by (8-37)hCGRP (1 microM). Our results suggest that CGRP and amylin act on the B-cell, at least in part, through a common receptor.

Amylin inhibits glucose-induced insulin secretion in a dose-dependent manner. Study in the perfused rat pancreas

Islet amyloid polypeptide (IAPP), also called amylin, has been localized in the B-cell secretory granule and is co-secreted with insulin. We have investigated the effect of synthetic amidated rat amylin on the insulin release evoked by 9 mM glucose in the isolated, perfused rat pancreas. Amylin, in a range of 75 nM-75 pM, significantly inhibited this insulin response in a dose-dependent manner. The correlation between the logarithm of amylin concentrations and the percentages of inhibition was highly significant (r = 0.98, P < 0.01). The lowest effective amylin concentration tested (75 pM) is within the range of amylin levels reported for the effluent of the perfused rat pancreas. Finally, pre-infusion of the rat pancreas with a high amylin concentration (75 nM) did not alter the insulin response to glucose, thus excluding a toxic effect of amylin on the B-cell. These observations support the concept that amylin plays a role in the control of insulin secretion.

Effects of rat pancreatic polypeptide on islet-cell secretion in the perfused rat pancreas

Pancreatic polypeptide (PP) secretory cells are abundant in the islets of Langerhans. Results concerning the effects of exogenous PP on islet-cell secretion are controversial. This might be due in part to species specificity, given that most reports refer to studies performed using PP of bovine, porcine, or human origin in a heterologous animal model. Thus, we have investigated the influence of synthetic rat PP (80 nmol/L) on unstimulated insulin, glucagon, and somatostatin release, and on the responses of these hormones to glucose (11 mmol/L) and to arginine (3.5 mmol/L) in a homologous animal model, the perfused rat pancreas. Infusion of rat PP (rPP) reduced unstimulated insulin release by 35% (P = .03), and the insulin responses to glucose by 65% (P = .029) and to arginine by 50% (P = .026), without modifying glucagon output. rPP did not affect somatostatin secretion, either in unstimulated conditions or in the presence of 11 mmol/L glucose. However, it induced a clear-cut increase in somatostatin release during 3.5 mmol/L arginine infusion. Our observation that rPP inhibited insulin secretion without affecting glucagon and somatostatin output points to a direct effect of PP on B-cell function. However, during aminogenic priming of the D cell, the inhibition of insulin output induced by rPP was accompanied by an increase in somatostatin release. Thus, in this circumstance, it might be considered that the blocking effect of PP on B-cell secretion could be, at least in part, mediated by a D-cell paracrine effect.

Homologous pancreastatin inhibits insulin secretion without affecting glucagon and somatostatin release in the perfused rat pancreas

The identification of pancreastatin in pancreatic extracts prompted the investigation of its effects on islet cell function. However, in most of the investigations to date, pig pancreastatin was tested in heterologous species. Since there is great interspecies variability in the amino acid sequence of pancreastatin, we have investigated the influence of rat pancreastatin on insulin, glucagon and somatostatin secretion in a homologous animal model, namely the perfused rat pancreas. During 5.5 mM glucose infusion, pancreastatin (40 nM) inhibited insulin secretion (ca. 40%, P less than 0.025) as well as the insulin responses to 10 mM arginine (ca. 50%, P less than 0.025) and to 1 nM vasoactive intestinal polypeptide (ca. 50%; P less than 0.05). Pancreastatin failed to significantly modify glucagon or somatostatin release under any of the above experimental conditions. In addition, a lower pancreastatin concentration (15.7 nM) markedly suppressed the insulin release evoked by 11 mM glucose (ca. 85%, P less than 0.05). Our present observations reinforce the concept that pancreastatin is an effective inhibitor of insulin secretion, influencing the B-cell function directly and not through an A-cell or D-cell paracrine effect.

Inhibition of insulin release by amylin is not mediated by changes in somatostatin output

We have investigated the effect of a high concentration (750 nM) of synthetic amidated rat amylin on unstimulated somatostatin and insulin secretion as well as on the response of these hormones to arginine. Amylin consistently reduced insulin output but it did not significantly modify somatostatin release. These findings indicate that the inhibitory effect of amylin on insulin secretion is not mediated by a D-cell paracrine effect.

Inhibitory effect of rat amylin on the insulin responses to glucose and arginine in the perfused rat pancreas

Amylin, a 37-amino acid polypeptide, is the main component of amyloid deposits in the islets of Langerhans, and has been identified in the B-cell secretory granules. We have investigated the effect of rat amylin on the insulin and glucagon release by the isolated, perfused rat pancreas. Amylin infusion at 750 nM, markedly reduced unstimulated insulin release (ca. 50%, P less than 0.025), whereas it did not modify glucagon output. At the same concentration, amylin also blocked the insulin response to 9 mM glucose (ca. 80%, P less than 0.025) without affecting the suppressor effect of glucose on glucagon release. The inhibitory effect of amylin on glucose-induced insulin secretion was confirmed by lowering the amylin concentration (500 nM) and increasing the glucose stimulus (11 mM); again, no effect of amylin on glucagon release was observed. Finally, amylin, at 500 nM, reduced the insulin response to 3.5 mM arginine (ca. 40%, P less than 0.025) without modifying the secretion of glucagon elicited by this amino acid. It can be concluded that, in the rat pancreas, the inhibitory effect of homologous amylin on unstimulated insulin secretion, as well as on the insulin responses to metabolic substrates (glucose and arginine), favours the concept of this novel peptide as a potential diabetogenic agent.

Inhibition of insulin and somatostatin secretion and stimulation of glucagon release by homologous galanin in perfused rat pancreas

Results of studies on the effects of exogenous galanin on islet cell secretion are controversial. Until recently, only pig galanin has been available, and structural dissimilarities among the galanin molecules of different species might have contributed to discrepancies among the study results. Thus, we investigated the influence of synthetic rat galanin (50 nM) on unstimulated insulin, glucagon, and somatostatin release and on the responses of these hormones to arginine (10 mM), glucose (16.6 mM), and vasoactive intestinal polypeptide (VIP; 1 nM) in a homologous animal model, the perfused rat pancreas. In addition, the effect of an equimolar concentration of pig galanin on arginine-induced islet cell secretion was examined. Infusion of rat galanin reduced unstimulated insulin release (approximately 60%, P less than 0.01) and the insulin responses to arginine (approximately 30%, P less than 0.025), glucose (100%, P less than 0.01), and VIP (approximately 80%, P less than 0.025). Galanin also inhibited unstimulated somatostatin secretion (approximately 15%, P less than 0.05) and virtually abolished the somatostatin output evoked by arginine, glucose, and VIP. Conversely, rat galanin increased unstimulated glucagon output (approximately 20%, P less than 0.05), potentiated the glucagon response to arginine (approximately 50%, P less than 0.05) and VIP (approximately 90%, P less than 0.05), and counteracted the suppressor effect of glucose on alpha-cell secretion. Pig galanin inhibited the insulin output elicited by arginine (approximately 45%, P less than 0.05) but did not affect the somatostatin and glucagon responses to the aminogenic stimulus. In conclusion, the opposite effects of galanin on insulin and glucagon secretion favor the concept of galanin as a diabetogenic agent. Galanin also behaves as a potent inhibitor of somatostatin release. Finally, the importance of using homologous galanin to study the biological activity of this peptide must be emphasized.

Pancreastatin inhibits insulin secretion as induced by glucagon, vasoactive intestinal peptide, gastric inhibitory peptide, and 8-cholecystokinin in the perfused rat pancreas

Pancreastatin is a 49-amino acid straight chain molecule isolated from porcine pancreatic extracts. In the perfused rat pancreas, this peptide has been shown to inhibit unstimulated insulin release and the insulin responses to glucose, arginine, and tolbutamide. To further explore the influence of pancreastatin on islet cell secretion, the effect of synthetic porcine pancreastatin (a 2-micrograms priming dose, followed by constant infusion at a concentration of 15.7 nmol/L) was studied on the insulin, glucagon, and somatostatin responses to 1 nmol/L vasoactive intestinal peptide (VIP), 1 nmol/L gastric inhibitory peptide (GIP), and 1 nmol/L 26 to 33 octapeptide form of cholecystokinin (8-CCK). The effect of pancreastatin on the insulin and somatostatin secretion elicited by glucagon (20 nmol/L) was also examined. Pancreastatin infusion consistently reduced the insulin responses to VIP, GIP, and 8-CCK without modifying glucagon or somatostatin release. It also inhibited the insulin release but not the somatostatin output induced by glucagon. These observations broaden the spectrum of pancreastatin as an inhibitor of insulin release. The finding that pancreastatin does not alter glucagon or somatostatin secretion supports the concept that it influences the B cell directly, and not through an A cell or D cell paracrine effect.

In vitro effects of BAY K 8644, a dihydropyridine derivative with hypoglycaemic properties, on hepatic glucose production and pancreatic hormone secretion

In rats, oral administration of BAY K 8644 (methyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine-5- carboxylate), a dihydropyridine derivative, Ca2+-channel activator, lowers fasting glycaemia and improves glucose tolerance to carbohydrate loading without elevating peripheral plasma insulin. To study the hypoglycaemic mechanism of this compound, we have examined its effects on glucose production by isolated rat hepatocytes and on hormone secretion by the perfused rat pancreas. Incorporation of BAY K 8644 (0.2-10 microM) into the hepatocyte incubation medium failed to significantly modify glycogenolysis, gluconeogenesis or L-lactate production. Hepatocyte glycogen phosphorylase a (EC 2.4.1.1) activity and fructose 2,6-bisphosphate levels were also unaffected by BAY K 8644. In the perfused rat pancreas, BAY K 8644 markedly stimulated insulin release without modifying glucagon or somatostatin output. Thus, the possibility that this compound exerts its hypoglycaemic effect by provoking insulin secretion should be further investigated.

Effects of galanin on islet cell secretory responses to VIP, GIP, 8-CCK, and glucagon by the perfused rat pancreas

Exogenous galanin has been shown to suppress insulin secretion as elicited by a number of secretagogues such as glucose, arginine, tolbutamide, carbachol, and oral nutrients. To achieve further insight into the influence of galanin on the endocrine pancreas, we have investigated the effect of synthetic porcine galanin (a 200 ng bolus followed by constant infusion at a concentration of 16.8 ng/mL for 16 to 24 minutes) on unstimulated insulin, glucagon, and somatostatin release, as well as on the responses of these hormones to 1 nmol/L vasoactive intestinal peptide (VIP), 1 nmol/L gastric inhibitory peptide (GIP), 1 nmol/L 26 to 33 octapeptide form of cholecystokinin (8-CCK) or 10 nmol/L glucagon in the perfused rat pancreas. Galanin infusion reduced unstimulated insulin secretion by 60% without modifying glucagon and somatostatin output. Galanin also blocked insulin release elicited by VIP, GIP, and 8-CCK, it did not affect the glucagon responses to VIP and GIP, or the somatostatin responses to VIP, GIP, and 8-CCK. Finally, galanin inhibited the insulin output, but not the somatostatin release induced by glucagon. In conclusion, in the perfused rat pancreas, galanin appears to behave as a general inhibitor of insulin secretion. Since this neuropeptide does not modify glucagon or somatostatin release, a direct effect of galanin on the B-cell seems plausible.

Effects of pancreastatin on insulin, glucagon and somatostatin secretion by the perfused rat pancreas

Pancreastatin is a novel peptide, isolated from porcine pancreatic extracts, which has been shown to inhibit glucose-induced insulin release "in vitro". To achieve further insight into the influence of pancreastatin on pancreatic hormone secretion, we have studied the effects of this peptide on unstimulated insulin, glucagon and somatostatin output, as well as on the responses of these hormones to glucose and to tolbutamide in the perfused rat pancreas. Pancreastatin strongly inhibited unstimulated insulin release as well as the insulin responses to glucose and to tolbutamide. It did not significantly affect glucagon or somatostatin output under any of the above-mentioned conditions. These findings suggest that pancreastatin inhibits B-cell secretory activity directly, and not through an A-cell or D-cell paracrine effect.