The targeting of ß-cells by T lymphocytes in human type 1 diabetes: clinical perspectives.

This review focuses on genes that control ß-cell targeting in autoimmune, type 1-dependent, diabetes (T1D) and on insulin as the major autoantigen recognized by T lymphocytes throughout the disease process. T1D associates with multiple gene variants. Beyond genes that predispose to general failure of immune tolerance to self, loci identified by the analysis of crosses between non-obese diabetic (NOD) and conventional mouse strains harbour genes that control ß-cell targeting or the deviation of autoimmunity towards other tissues. We report here the role of genes encoding co-activation molecules involved in the activation of T lymphocytes, ICOS and ICOS ligand (B7RP1). NOD mice which are deficient in either of these two molecules are protected from diabetes, but instead develop a neuromuscular autoimmune disease. We also report the characterization in humans of T lymphocytes that are specific for major ß-cell autoantigens, especially insulin. This opens the way towards new bioassays in the diagnosis of autoimmunity and towards autoantigen-specific immunotherapy in T1D. In order to develop a new preclinical model of T1D that would allow testing insulin epitopes to induce immune tolerance in vivo, we developed a mouse that is deficient in endogenous major histocompatibility complex class I and class II genes and deficient for the two murine insulin genes and that express human class I, class II and insulin genes.

French Endocrine Society Guidance on endocrine side effects of immunotherapy.

The management of cancer patients has changed due to the considerably more frequent use of immune checkpoint inhibitors (ICPIs). However, the use of ICPI has a risk of side effects, particularly endocrine toxicity. Since the indications for ICPI are constantly expanding due to their efficacy, it is important that endocrinologists and oncologists know how to look for this type of toxicity and how to treat it when it arises. In view of this, the French Endocrine Society initiated the formulation of a consensus document on ICPI-related endocrine toxicity. In this paper, we will introduce data on the general pathophysiology of endocrine toxicity, and we will then outline expert opinion focusing primarily on methods for screening, management and monitoring for endocrine side effects in patients treated by ICPI. We will then look in turn at endocrinopathies that are induced by ICPI including dysthyroidism, hypophysitis, primary adrenal insufficiency and fulminant diabetes. In each chapter, expert opinion will be given on the diagnosis, management and monitoring for each complication. These expert opinions will also discuss the methodology for categorizing these side effects in oncology using 'common terminology criteria for adverse events' (CTCAE) and the difficulties in applying this to endocrine side effects in the case of these anti-cancer therapies. This is shown in particular by certain recommendations that are used for other side effects (high-dose corticosteroids, contraindicated in ICPI for example) and that cannot be considered as appropriate in the management of endocrine toxicity, as it usually does not require ICPI withdrawal or high-dose glucocorticoid intake.

TRα Mutations in Human.

Resistance to thyroid hormone alpha is an emerging syndrome, with up to now a limited number of published cases. Some features are common to most of the patients, but there is still some work to provide a comprehensive description of the full spectrum of the syndrome. A survey of the strategy to screen for and characterize the mutations in TR α gene is given.

The use of intravenous catheterisation with a rest period is useful for determination of plasma cortisol levels but not plasma prolactin levels.

OBJECTIVE: The use of an intravenous catheter with a rest period has been recommended to avoid false-positive results for hyperprolactinaemia and false-negative results for hypocortisolaemia. We tested the relevance of this recommendation. DESIGN: Plasma cortisol and prolactin levels were determined before (T-15) and after a 15-min rest period (T0) in 119 patients, 38 males (M) and 81 females (F). 52 of the 119 patients were known (K; 30 females and 22 males) and 67 unknown (UK; 49 females and 18 males) to the unit. RESULTS: Prolactin was lower after rest in women (12.3+/-22.7 ng/l vs 11.7+/-22.5 ng/ml, P=0.03), but not in men (6.2+/-4.5 ng/ml at T-15 vs 5.8+/-3.2 ng/ml at T0, P=0.09), in the UK subgroup (10.6+/-20.7 ng/ml at T-15 vs 10.1+/-20.9 ng/ml at T0, P=0.06) and in the K subgroup (10.1+/-16.7 ng/ml at T-15 vs 9.7+/-15.8 ng/ml at T0, P=0.08). None of the patients with prolactin levels higher than 20 ng/ml at T-15 diminished its prolactin value below this cut-off value. Plasma cortisol levels were lower after rest in women (17.9+/-5.9 microg/dl at T-15 vs 16.5+/-6.1 microg/dl at T0, P<0.0001), in the UK subgroup (18+/-6.1 microg/dl at T-15 vs 16.6+/-6.4 microg/dl at T0, P=0.0003) but not in men (18+/-4.4 microg/dl at T-15 vs 17.5+/-5.8 microg/dl at T0, P=0.47) and in the K subgroup (17.8+/-4.6 microg/dl at T-15 vs 17+/-5.4 microg/dl at T0, P=0.13). At T0, 3.3% and 15% of patients presented values below the cut-off value of 10 microg/dl (276 nmol/l) and 17 microg/dl (470 nmol/l), respectively. CONCLUSION: These results don't justify intravenous catheterisation with a rest period for plasma prolactin determination in contrast with plasma cortisol determination.

Lesson to be remembered from a skull base tumor.

The natural history of giant prolactinomas is not known. While it is commonly accepted that the enlargement of microadenoma is rare and more limited than macroadenoma, it is so far uncommon that macroadenoma progress to giant adenoma. Thus, spontaneous enlargement of adenomas is poorly documented. We report the unusual history of undiagnosed microprolactinoma, revealed 12years later at the stage of a giant adenoma presenting as a skull base tumor. This unique observation provides information on the natural history of giant adenomas and arguments for particular attention to microadenomas with signs of invasion. Moreover, this clinical case highlights the need for a prolactin dosage for all midline skull base tumors.

Cabergoline for Cushing's disease: a large retrospective multicenter study.

OBJECTIVE: The efficacy of cabergoline in Cushing's disease (CD) is controversial. The aim of this study was to assess the efficacy and tolerability of cabergoline in a large contemporary cohort of patients with CD. DESIGN: We conducted a retrospective multicenter study from thirteen French and Belgian university hospitals. METHODS: Sixty-two patients with CD received cabergoline monotherapy or add-on therapy. Symptom score, biological markers of hypercortisolism and adverse effects were recorded. RESULTS: Twenty-one (40%) of 53 patients who received cabergoline monotherapy had normal urinary free cortisol (UFC) values within 12 months (complete responders), and five of these patients developed corticotropic insufficiency. The fall in UFC was associated with significant reductions in midnight cortisol and plasma ACTH, and with clinical improvement. Compared to other patients, complete responders had similar median baseline UFC (2.0 vs 2.5xULN) and plasma prolactin concentrations but received lower doses of cabergoline (1.5 vs 3.5 mg/week, P < 0.05). During long-term treatment (>12 months), cabergoline was withdrawn in 28% of complete responders because of treatment escape or intolerance. Overall, sustained control of hypercortisolism was obtained in 23% of patients for 32.5 months (19-105). Nine patients on steroidogenesis inhibitors received cabergoline add-on therapy for 19 months (1-240). Hypercortisolism was controlled in 56% of these patients during the first year of treatment with cabergoline at 1.0 mg/week (0.5-3.5). CONCLUSIONS: About 20-25% of CD patients are good responders to cabergoline therapy allowing long-term control of hypercortisolism at relatively low dosages and with acceptable tolerability. No single parameter, including the baseline UFC and prolactin levels, predicted the response to cabergoline.

Structure-activity relationships of C-terminal tri- and tetrapeptide fragments that inhibit gastrin activity.

A series of tri- and tetrapeptide derivatives, analogues of the gastrin C-terminal region with no phenylalanine residue, were synthesized. These peptides were tested for their ability to inhibit gastrin-stimulated acid secretion in vivo as well as binding of [125I]-(Nle11)-HG-13 to gastric mucosal cell receptors in vitro. Most of the peptides tested exhibited gastrin antagonist activity in vivo and in vitro. Most active derivatives were 20-30 times more potent than the well-known gastrin antagonist derivatives proglumide and benzotript and had 20-200 times more binding affinity. The smallest fragment exhibiting antagonist activity was the tripeptide Boc-L-tryptophyl-L-methionyl-L-aspartic acid amide.

Evidence for dopaminomimetic effect of intrastriatally injected cholecystokinin octapeptide in mice.

The behavioural effect of intrastriatally injected cholecystokinin sulphated octapeptide (CCK-8S), and its interactions with the antagonists Z-CCK-(27-32)NH2 and proglumide, were investigated in mice. When injected into the right striatum, CCK-8S (0.05-1 ng) induced contralateral rotations, as did the dopamine agonist apomorphine. Non-sulphated CCK-8 was inactive and sulphated desamino-CCK-7 was only weakly active in this respect. CCK-8S-induced turning was antagonized by co-injected Z-CCK-(27-32)NH2 (0.01-10 ng) or proglumide (0.1-1 micrograms), as well as by intraperitoneal injection of the neuroleptic drug haloperidol. These data suggest that CCK-8S may, in these conditions, stimulate dopamine-mediated neurotransmission, and that Z-CCK-(27-32)NH2, in addition to its peripheral effect, is also a very potent CCK antagonist at the striatal level.

Metformin accumulation without hyperlactataemia and metformin-induced hyperlactataemia without metformin accumulation.

AIM: These case reports demonstrate that, at the individual level, blood metformin concentrations and metformin effects on lactate do not always correlate. METHODS: We report here on two unusual cases: metformin accumulation in the absence of hyperlactataemia; and metformin-induced hyperlactataemia with no metformin accumulation. RESULTS: Patient #1 presented with severe kidney failure, severe acidosis (pH: 7.04), normal lactataemia (0.90 mmol/L) and marked metformin accumulation. Patient #2 presented with hyperlactataemia, even after dose reduction, during otherwise well-tolerated metformin treatment. Arterial lactate levels were 8.8, 8.2 and 4.7 mmol/L during metformin therapy with daily doses of 2550, 1700 and 850 mg, respectively. After withdrawal, metformin was reintroduced for 5-day periods at 500 mg/day up to 2000 mg/day with washout intervals. Lactate concentration, normal at baseline, rapidly exceeded 2 mmol/L after metformin administration. CONCLUSION: These clinical data suggest a new concept for metformin therapy: there may be either resistance or, conversely, hypersensitivity to metformin effects on lactate generation according to the individual patient.

[Pituitary disease: which treatment in the future?]. / Pathologie hypophysaire: quels traitements pour le futur ?

Even if major progress has been made in the medical treatment for pituitary adenomas in the last decades, currently available drugs do not always control hormonal secretion of these tumors. New molecules or new formulations of old drugs are under development. Pituitary stem cells research is currently also very active.

Synthesis of Z-CCK-27-32-NH2, Z-Tyr(SO-3)-Met-Gly-Trp-Met-Asp-NH2, a cholecystokinin receptor antagonist and an inhibitor of gastrin-induced acid secretion.

The synthesis of the hexapeptide Z-Tyr(SO-3)-Met-Gly-Trp-Met-Asp-NH2, representing the C-terminal sequence of cholecystokinin minus the C-terminal phenylalanyl residue is described. This peptide was shown to be the most potent cholecystokinin receptor antagonist in vitro described to date. It is also able to inhibit gastrin-induced acid secretion in vivo, in the rat and was proved to antagonize the action of the C-terminal octapeptide of cholecystokinin in the central nervous system.

Cholecystokinin-27-32-amide. A member of a new class of cholecystokinin receptor antagonists.

In dispersed acini from guinea pig pancreas, cholecystokinin-27-32-amide (CCK-27-32-NH2) did not alter amylase secretion but was able to antagonize the stimulation caused by cholecystokinin-related agonists. CCK-27-32-NH2 caused a parallel rightward shift in the dose-response curve for the stimulation of amylase secretion caused by cholecystokinin and inhibited binding of 125I-labeled cholecystokinin to pancreatic acini. These results indicate that CCK-27-32-NH2 is a fully competitive cholecystokinin receptor antagonist. CCK-27-32-NH2 did not alter the rate of dissociation of bound 125I-cholecystokinin from pancreatic acini but was able to reverse the residual stimulation of enzyme secretion caused by first incubating pancreatic acini with a relatively high concentration of cholecystokinin. Compared to other cholecystokinin receptor antagonists, CCK-27-32-NH2 is the most potent antagonist described to date, i.e. 30 times more potent than N2,O2-dibutyryl guanosine 3':5'-monophosphate. These results also indicate that the COOH-terminal phenylalanine residue of cholecystokinin is essential for intrinsic cholecystokinin-like activity but is not essential for binding of the peptide to cholecystokinin receptors in pancreatic acini.