Safety and immunogenicity of a mRNA rabies vaccine in healthy adults: an open-label, non-randomised, prospective, first-in-human phase 1 clinical trial

BACKGROUND

Vaccines based on mRNA coding for antigens have been shown to be safe and immunogenic in preclinical models. We aimed to report results of the first-in-human proof-of-concept clinical trial in healthy adults of a prophylactic mRNA-based vaccine encoding rabies virus glycoprotein (CV7201).

METHODS

We did an open-label, uncontrolled, prospective, phase 1 clinical trial at one centre in Munich, Germany. Healthy male and female volunteers (aged 18-40 years) with no history of rabies vaccination were sequentially enrolled. They received three doses of CV7201 intradermally or intramuscularly by needle-syringe or one of three needle-free devices. Escalating doses were given to subsequent cohorts, and one cohort received a booster dose after 1 year. The primary endpoint was safety and tolerability. The secondary endpoint was to determine the lowest dose of CV7201 to elicit rabies virus neutralising titres equal to or greater than the WHO-specified protective antibody titre of 0·5 IU/mL. The study is continuing for long-term safety and immunogenicity follow-up. This trial is registered with ClinicalTrials.gov, number NCT02241135.

FINDINGS

Between Oct 21, 2013, and Jan 11, 2016, we enrolled and vaccinated 101 participants with 306 doses of mRNA (80-640 μg) by needle-syringe (18 intradermally and 24 intramuscularly) or needle-free devices (46 intradermally and 13 intramuscularly). In the 7 days post vaccination, 60 (94%) of 64 intradermally vaccinated participants and 36 (97%) of 37 intramuscularly vaccinated participants reported solicited injection site reactions, and 50 (78%) of 64 intradermally vaccinated participants and 29 (78%) of 37 intramuscularly vaccinated participants reported solicited systemic adverse events, including ten grade 3 events. One unexpected, possibly related, serious adverse reaction that occurred 7 days after a 640 μg intramuscular dose resolved without sequelae. mRNA vaccination by needle-free intradermal or intramuscular device injection induced virus neutralising antibody titres of 0·5 IU/mL or more across dose levels and schedules in 32 (71%) of 45 participants given 80 μg or 160 μg CV7201 doses intradermally and six (46%) of 13 participants given 200 μg or 400 μg CV7201 doses intramuscularly. 1 year later, eight (57%) of 14 participants boosted with an 80 μg needle-free intradermal dose of CV7201 achieved titres of 0·5 IU/mL or more. Conversely, intradermal or intramuscular needle-syringe injection was ineffective, with only one participant (who received 320 μg intradermally) showing a detectable immune response.

INTERPRETATION

This first-ever demonstration in human beings shows that a prophylactic mRNA-based candidate vaccine can induce boostable functional antibodies against a viral antigen when administered with a needle-free device, although not when injected by a needle-syringe. The vaccine was generally safe with a reasonable tolerability profile.

FUNDING

CureVac AG.

[Cost of systemic lupus erythematosus for adult patients with active and treated disease in France (LUCIE study)]

PURPOSE

To evaluate in France the annual direct medical cost of adult patients with active systemic lupus erythematosus (SLE) on medication and estimate the cost of a flare.

METHODS

A two-year, observational, retrospective, multicenter study, carried out between December 2010 and February 2011. Patients' characteristics, SLE disease activity and severity, rate of flares, healthcare consumption (medications, hospitalisations, etc.) were evaluated. Medical costs were assessed from the national Health Insurance perspective. Cost predictors were estimated using multivariate regression models.

RESULTS

Eight centres specialized in SLE management included 93 eligible patients (including 50.5% severe). The mean age was 39.9 (11.9) years and 93.5% were women. At baseline, the mean SLE duration was 9.8 (6.6) years. The mean scores of the SELENA-SLEDAI instrument and the SLICC/ACR index were higher in severe patients (9.8 vs 5.6, and 1.2 vs 0.4 respectively; P<0.001). Over the study period, 51% of patients received the combination containing at least corticosteroids or immunosuppressants. The mean annual direct medical cost of severe patients was €4660 versus €3560 for non-severe patients (non-significant difference). The cost of medications (61.8% of the annual cost) was higher in severe patients (€3214 vs €1856; P<0.05). Immunosuppressants and biologics represented 26.5% and 4.6% of the annual total cost respectively. Patients experienced on average 1.10 (0.59) flares/year, of which 0.50 were severe flare. The occurrence of a new severe flare incremented the annual cost of €1330 (P<0.05).

CONCLUSION

Medications represented the major component of the annual direct medical cost. Severe flares increase significantly the cost of SLE care management.

Patterns of systemic lupus erythematosus expression in Europe

OBJECTIVES

To analyse the differences in disease expression of European SLE patients based on gender, age at diagnosis, and ethnicity.

METHODS

A two-year, retrospective, multicentre, observational study was carried out in five countries (France, Germany, Italy, Spain and the UK). Patients' clinical manifestations including disease activity, organ involvement, organ damage and flares were analysed.

RESULTS

Thirty-one centres enrolled 412 consecutive eligible patients (90.5% of women), with active disease, stratified by disease severity (half severe and half non-severe). Baseline characteristics included; mean (SD) age: 43.3 (13.6) years, SLE duration: 10.7 (8.0) years and age at disease diagnosis: 32.6 (13.0) years old. The mean (SD) SELENA-SLEDAI and SLICC/ACR scores were: 8.1 (6.7) and 0.82 (1.36), respectively. Over half of patients experienced flares (54.9%). The average number of annual flares was 1.01 (0.71) flares/year. In males compared to females, the renal system was more frequently active (53.8% vs 30.0%, p=0.002), the mean SLICC/ACR score was higher (1.15 vs 0.79, p=0.039) and the pulmonary system was more likely to be damaged (12.8% vs 3.8%, p=0.010). Furthermore, patients diagnosed at younger age displayed more renal system activity (young: 56.3% vs adult: 33.4% vs elder: 8.9%, p<0.001) and renal damage (25.0% vs 6.9% vs 2.2%, p=0.018) compared to the others. The annual number of flares (1.13 vs 1.05 vs 0.81 flares/year, p<0.0001), including the occurrence of severe flares (0.58 vs 0.51 vs 0.20, p<0.0001), was also higher in these patients. Conversely, greater organ damage was observed in patients diagnosed at an older age compared to the others. The mean SLICC/ACR score was higher (1.31 vs young: 0.88 and adult: 0.78, p<0.001) in patients diagnosed in the older age groups. The pulmonary (13.3% vs younger: 0% vs adult: 3.7%, p=0.030) and cardiovascular (17.8% vs younger: 0% vs adult: 2.9%, p<0.001) systems were more frequently damaged in these patients. Black African descents showed greater disease activity compared to Caucasian patients. They flared more often (77.1% vs 48.6%, p=0.001) and experienced a greater number of annual flares (1.57 vs 0.89 flares/year, p<0.0001), mainly more severe flares (0.89 vs 0.38/year, p<0.0001). They also were more likely to experience renal system damage.

CONCLUSION

The study showed clearly two patient subsets. The disease was the most active in Black African descents, and this phenomenon has never been described before in continental Europe. The disease was also more active in patients diagnosed at a younger or adult. Greater disease damage was observed in males and in patients diagnosed at an older age.

Eperisone versus tizanidine for treatment of chronic low back pain

AIM

Many therapies exist for treatment of chronic low-back pain (LBP) including the use of muscle relaxant and analgesic drugs. The aim of this paper was to compare efficacy and tolerability of eperisone and tizanidine in combination treatment with tramadol in chronic LBP.

METHODS

Sixty patients affected by chronic LBP associated with contractures of paravertebral muscles were randomized in two groups: Group E (30 patients) treated with eperisone; Group T (30 patients) treated with tizanidine. Both groups received tramadol retard 100 mg/day. VAS at rest and with effort were used at baseline (T0) and after 5 (T5), 10 (T10), 15 (T15) and 30 (T30) days of treatment. The Summed Pain Intensity Difference (SPID), the SPID percentage (SPID%) and the Total Pain Relief (TOTPAR), at rest (-r) and with effort (-e) were calculated.

RESULTS

In both groups a statistically significant reduction in VAS-r and VAS-e was observed during the treatment; similar reductions occurred in both groups at every timepoint. SPID-r and -e, SPID%-r and -e and TOTPAR-r and -e resulted similar between groups. A significant difference between groups occurred for incidence of somnolence: 16.6% for Group E versus 43.3% for Group T. Treatment was stopped due to adverse events in 5 patients of Group E and in 9 patients of Group T, without statistically significant difference.

CONCLUSION

Both associations assumed for one month, have shown effective for LBP at rest and with effort. Eperisone/tramadol, reducing discontinuation and allowing a better adherence to the therapy, may be considered a viable option for the treatment of chronic LBP.

Substrate-inducible versions of internal alternative NADH: ubiquinone oxidoreductase from Yarrowia lipolytica

In standard laboratory strains of the obligate aerobic yeast Yarrowia lipolytica, respiratory chain complex I (proton-translocating NADH : ubiquinone oxidoreductase) is an essential enzyme, since alternative NADH dehydrogenase activity is located exclusively at the external face of the mitochondrial inner membrane. Deletions and other loss-of-function mutations in genes for nuclear coded subunits of complex I can be obtained only when an internal version of the latter enzyme, termed NDH2i, is introduced. In contrast to recent findings with Neurospora crassa, external alternative NADH dehydrogenase activity is dispensable in complex I deletion strains of Y. lipolytica. We used regulable promoters to create strains which express internal alternative NADH dehydrogenase in a substrate-dependent manner. The ability to switch between complex I-dependent and -independent mode of growth simply by changing the carbon source is an important prerequisite for screens for both loss-of-function and inhibitor resistance mutation. The isocitrate lyase promoter (pICL1), in combination with a NDH2i allele that results in reduced expression and activity, was most promising. In the presence of complex I inhibitors, this construct allowed growth on acetate, but not on glucose minimal media. A somewhat higher background was observed with the acyl-CoA oxidase 2 (pPOX2) promoter on glucose minimal media.

Semisynthesis and screening of a small library of pro-apoptotic squamocin analogues: selection and study of a benzoquinone hybrid with an improved biological profile

Acetogenins of Annonaceae, including squamocin (1), exert spectacular cytotoxicity and the most potent inhibition of NADH:ubiquinone oxidoreductase known so far. Cell death induced by these natural products was identified as apoptosis and was thought to be linked to alterations in mitochondrial function. Quinone-squamocin hybrid compounds were semisynthesized and evaluated for their pro-apoptotic properties with a screening method based on dissipation of the mitochondrial transmembrane potential (DeltaPsim). Herein, we report a short one-step synthesis of a squamocin carboxylic acid analogue. For the first time on a natural product, the radical decarboxylation and quinone addition reaction has enabled preparation of a library of squamocin-quinone hybrids and four other analogues. Squamoquinone, tenfold more potent than squamocin as an inducer of apoptosis, emerged as a promising compound, as it induces apoptosis through a mitochondrial caspase-dependent pathway.

Heterocyclic analogues of squamocin as inhibitors of mitochondrial complex I. On the role of the terminal lactone of annonaceous acetogenins

Heterocyclic analogues of squamocin have been semisynthesized by condensation reactions between squamocin-derived alpha-keto esters and heterodinucleophiles. The strong complex I inhibitory potency of squamocin-benzimidazole, a hybrid derivative, illustrates for the first time the functional analogy existing between the terminal butenolide of annonaceous acetogenins and heteroaromatic substructures of classic inhibitors of the enzyme. This finding supports the categorization of this atypical group of inhibitors as antagonists of the ubiquinone substrates. In addition, competition experiments of squamocin-benzimidazole versus squamocin and rolliniastatin-2 suggest that the binding of this hybrid inhibitor is responsible for a negative allosteric effect at the level of the first ubiquinone-binding site (A site) of mitochondrial complex I. This result supports the existence of a large cooperatively regulated inhibitor/ubiquinone-binding pocket located within the catalytic core of the enzyme, consisting of the association of the previously defined affinity sites A and B.

Application of the yeast Yarrowia lipolytica as a model to analyse human pathogenic mutations in mitochondrial complex I (NADH:ubiquinone oxidoreductase)

While diagnosis and genetic analysis of mitochondrial disorders has made remarkable progress, we still do not understand how given molecular defects are correlated to specific patterns of symptoms and their severity. Towards resolving this dilemma for the largest and therefore most affected respiratory chain enzyme, we have established the yeast Yarrowia lipolytica as a eucaryotic model system to analyse respiratory chain complex I. For in vivo analysis, eYFP protein was attached to the 30-kDa subunit to visualize complex I and mitochondria. Deletions strains for nuclear coded subunits allow the reconstruction of patient alleles by site-directed mutagenesis and plasmid complementation. In most of the pathogenic mutations analysed so far, decreased catalytic activities, elevated K(M) values, and/or elevated I(50) values for quinone-analogous inhibitors were observed, providing plausible clues on the pathogenic process at the molecular level. Leigh mutations in the 49-kDa and PSST homologous subunits are found in regions that are at the boundaries of the ubiquinone-reducing catalytic core. This supports the proposed structural model and at the same time identifies novel domains critical for catalysis. Thus, Y. lipolytica is a useful lower eucaryotic model that will help to understand how pathogenic mutations in complex I interfere with enzyme function.

Management of French patients with type 2 diabetes mellitus in medical general practice: report of the Mediab observatory

OBJECTIVES

The Mediab study was conducted to estimate the medical care in French patients with type 2 diabetes mellitus managed by general practitioners on an ambulatory basis, but consIdered as requiring new treatment implementation.

METHODS

Five thousand one hundred and fourty eight diabetic patients without any treatment or treated with lifestyle measures either alone or combined with an oral antIdiabetic agent given as monotherapy were included in a cross-sectional study that was conducted on a nationwIde basis by using the ORP (R) methodology. The 4088 patients in whom HbA1c was determined with a reliable method were further classified into 3 categories according to whether HbA1c was<=6.5% (group I, n=525), ranging between 6.6 and 8% (group II, n=1699) or > 8% (group III, n=1864).

RESULTS

A large proportion of patients (45.6%) exhibited HbA1c > 8%. Adherence to diet and regular physical activity were progressively decreasing while prevalence of diabetic complications was steadily increasing from group I to III, i.e. when diabetic control was worsening. The complications suffered from severe "underreporting". When complications were reported, the odds-ratio analysis showed that retinopathy is influenced by both the magnitude of glucose excess and the diabetes duration, while renal diseases and macroangiopathy depend mainly on diabetes duration. 38.1% of patients visited a diabetologist, but most of these patients were referred to the speciaList after the inclusion visit.

CONCLUSIONS

Despite the development of guIdelines, a large percentage of patients remains poorly-controlled. Future actions should be based on: (i) better collaboration between general practitioners and diabetologists (ii) better detection of complications that suffer from severe "underreporting", (iii) reinforcement of lifestyle recommendations and of pharmacological treatments by shifting from mono- to multi-drug therapy, at earlier stages of the disease.

Two aspartic acid residues in the PSST-homologous NUKM subunit of complex I from Yarrowia lipolytica are essential for catalytic activity

Mitochondrial proton-translocating NADH:ubiquinone oxidoreductase (complex I) couples the transfer of two electrons from NADH to ubiquinone to the translocation of four protons across the mitochondrial inner membrane. Subunit PSST is the most likely carrier of iron-sulfur cluster N2, which has been proposed to play a crucial role in ubiquinone reduction and proton pumping. To explore the function of this subunit we have generated site-directed mutants of all eight highly conserved acidic residues in the Yarrowia lipolytica homologue, the NUKM protein. Mutants D99N and D115N had only 5 and 8% of the wild type catalytic activity, respectively. In both cases complex I was stably assembled but electron paramagnetic resonance spectra of the purified enzyme showed a reduced N2 signal (about 50%). In terms of complex I catalytic activity, almost identical results were obtained when the aspartates were individually changed to glutamates or to glycines. Mutations of other conserved acidic residues had less dramatic effects on catalytic activity and did not prevent assembly of iron-sulfur cluster N2. This excludes all conserved acidic residues in the PSST subunit as fourth ligands of this redox center. The results are discussed in the light of the structural similarities to the homologous small subunit of water-soluble [NiFe] hydrogenases.

Phase II trial of thalidomide in renal-cell carcinoma

BACKGROUND

Thalidomide has been reported to yield anti-tumor activity in cancer. We performed a phase II trial of this drug in patients with metastatic renal cell carcinoma to determine its efficacy.

PATIENTS AND METHODS

Patients with proven metastatic renal cell cancer, measurable progressive disease and a performance status of 0-2 were enrolled in this study. Thalidomide was given daily at a starting dose of 400 mg, followed by a 400 mg increment to 800 mg and then to 1200 mg with 6-12 weeks at each dose level. The response rate at 6 months was the primary end point. Toxicity, overall survival, tumor vascularization depicted on color Doppler ultrasonography and serum vascular endothelial growth factor, basic fibroblast growth factor, interleukin-12 and tumor necrosis factor-alpha levels were secondary end points.

RESULTS

Forty patients were enrolled. Two partial responses were observed (5%) and disease remained stable in nine patients after 6 months. Median survival was 10 months. Toxicity was high, with frequent manifestations of fatigue, constipation and lethargy. The incidence of neuropathy detected on electromyography (EMG) attained 70% at 6 months, and 100% in patients on thalidomide for 12 months. Nine patients developed venous thromboembolism during the first 12 weeks of treatment, and three of them experienced pulmonary embolism. One unexpected (and unexplained) death occurred.

CONCLUSIONS

Despite undisputed, albeit marginal, activity in renal cell cancer, high-dose thalidomide cannot be recommended using this schedule since the level of toxicity is high.

Impaired beta-cell regeneration in perinatally malnourished rats: a study with STZ

We investigated the mechanisms implicated in beta-cell mass reduction observed during late fetal and early postnatal malnutrition in the rat. Beta-cell regeneration, including proliferation and neogenesis, was studied after neonatal beta-cell destruction by streptozotocin (STZ). STZ was injected at birth and maternal food restriction was continued until weaning. Beta-cell mass, proliferation, and islet number were quantified by morphometrical measurements on pancreatic sections in STZ-injected normal (C-STZ) and malnourished (R-STZ) rats, with noninjected C and R rats as controls. At day 4, only 20% of the beta cell-mass remained in C-STZ rats. It regenerated to 50% that of noninjected controls, mainly through active neogenesis, as shown by the entire recovery of islet number/cm(2), and also through moderately increased beta-cell proliferation. In contrast, beta-cell mass from R-STZ animals poorly regenerated, despite a dramatic increase of beta-cell proliferation, because islet number/cm(2) recovered insufficiently. In conclusion, perinatal malnutrition impairs neogenesis and the capacity of beta-cell regeneration by neogenesis but preserves beta-cell proliferation, which remains the elective choice to increase beta-cell mass. These results provide an explanation for the impaired capacity of malnourished animals to adapt their beta-cell mass during aging or pregnancy, which aggravate glucose tolerance.

Postnatal somatic growth and insulin contents in moderate or severe intrauterine growth retardation in the rat

A rat model of perinatal malnutrition was designed to study the role of nutrition in postnatal somatic growth and insulin stores until adulthood. Maternal food restriction (50%) from day 15 of pregnancy resulted in intrauterine growth retardation (IUGR) in the offspring. The outcome of moderate or severe IUGR was investigated. Neonates with moderate IUGR normally nourished postnatally showed normal body and organ weights and normal insulin contents in adulthood. Offspring with severe IUGR normally nourished postnatally also rapidly recovered normal body and pancreatic weights, but liver and kidney weights were significantly reduced at adult age. Malnutrition until weaning in offspring with severe IUGR induced marked growth retardation (50%) in body and organ weights at weaning. Although pancreatic weight recovered at adult age, body, liver and kidney weights were irreversibly affected, despite several months of normal nutrition. Furthermore, severe IUGR at birth resulted in decreased insulin content at adult age, irrespective of postnatal nutrition. In conclusion, this animal model demonstrates that normalization of adult size can be dissociated from organ growth and also that altered insulin stores in adulthood are more dependent on the severity of IUGR at birth than on postnatal catch-up in organ growth.

Application of the obligate aerobic yeast Yarrowia lipolytica as a eucaryotic model to analyse Leigh syndrome mutations in the complex I core subunits PSST and TYKY

We have used the obligate aerobic yeast Yarrowia lipolytica to reconstruct and analyse three missense mutations in the nuclear coded subunits homologous to bovine TYKY and PSST of mitochondrial complex I (proton translocating NADH:ubiquinone oxidoreductase) that have been shown to cause Leigh syndrome (MIM 25600), a severe progressive neurodegenerative disorder. While homozygosity for a V122M substitution in NDUFS7 (PSST) has been found in two siblings with neuropathologically proven Leigh syndrome (R. Triepels et al., Ann. Neurol. 45 (1999) 787), heterozygosity for a P79L and a R102H substitution in NDUFS8 (TYKY) has been found in another patient (J. Loeffen et al., Am. J. Hum. Genet. 63 (1998) 1598). Mitochondrial membranes from Y. lipolytica strains carrying any of the three point mutations exhibited similar complex I defects, with V(max) being reduced by about 50%. This suggests that complex I mutations that clinically present as Leigh syndrome may share common characteristics. In addition changes in the K(m) for n-decyl-ubiquinone and I(50) for hydrophobic complex I inhibitors were observed, which provides further evidence that not only the hydrophobic, mitochondrially coded subunits, but also some of the nuclear coded subunits of complex I are involved in its reaction with ubiquinone.

Age-dependent inability of the endocrine pancreas to adapt to pregnancy: a long-term consequence of perinatal malnutrition in the rat

We have recently shown that maternal food restriction during late pregnancy decreased beta-cell mass in the offspring at birth. Prolonged maternal malnutrition until weaning led to irreversible decrease of beta-cell mass in the adult male progeny. During pregnancy, the maternal endocrine pancreas demonstrates an acute and reversible increase in beta-cell mass. The aim of this work was to investigate whether perinatal malnutrition could have long-lasting effects on glucose homeostasis and the adaptation of the endocrine pancreas to a subsequent pregnancy. This study was conducted on 4- and 8-month-old female rats malnourished during their perinatal life and on age-matched control animals. Oral glucose tolerance tests (OGTT), pancreatic insulin content, and islet mass quantitation after dithizone staining were performed on the same animals. Four-month-old nonpregnant previously malnourished animals showed normal glucose tolerance but a significant decrease in insulin secretion during OGTT. These animals were, however, still able to adapt pancreatic insulin contents and doubled their islet mass in late gestation. At 8 months of age, insulin content before pregnancy was reduced to half that of controls. Moreover, it did not show the characteristic increase during gestation that could still be observed in pregnant control females. In those control animals, the islet mass increased regularly until late gestation (14.1+/-1.8 mg at day 20.5, vs. 9.8+/-1.2 mg, nonpregnant), whereas in previously malnourished animals the islet mass remained throughout pregnancy similar to the nonpregnant values (8.5+/-1.4 mg at day 20.5 vs. 8.9+/-3.6 mg, nonpregnant). In conclusion, early malnutrition has dramatic consequences on the capacity of the endocrine pancreas to meet the increased insulin demand during pregnancy and aging.

Effect of ageing on beta-cell mass and function in rats malnourished during the perinatal period

AIMS/HYPOTHESIS

In a recently developed rat model, maternal food restriction from day 15 of pregnancy until weaning induced low birth weight and a 70% reduction of beta-cell mass in the offspring at day 21 after birth. Subsequent renutrition from weaning was insufficient to fully restore beta-cell mass in young adult rats. The aim of this study is to investigate the long-term consequences of early malnutrition on beta-cell mass and function.

METHODS

Oral glucose tolerance tests were done in 3- and 12-month-old animals and beta-cell mass and apoptosis were determined by morphometrical measurements on pancreatic sections. The specific impact of postnatal malnutrition was studied by comparing control animals (C group) with animals malnourished during their fetal life only (R/C group), and animals malnourished during fetal life and until weaning (R group).

RESULTS

In 3-month-old R/C animals beta-cell mass reached 8.0 +/- 1.5 mg with no further increase until 12 months (8.1 +/- 1.5 mg), compared with 9.3 +/- 1.9 mg in control rats. Twelve-month-old R/C animals showed normal plasma insulin responses and borderline glucose tolerance. In R animals, apoptosis reached 1.9 +/- 0.4% of the beta cells at 3 months, compared with 0.7 +/- 0.5% in control rats, and beta-cell mass did not increase between 3 and 12 months (4.7 +/- 0.8 mg at 12 months). In aged control and R animals, apoptosis affected 8% of the beta cells. At 12 months only, R animals showed profound insulinopenia and marked glucose intolerance.

CONCLUSION/INTERPRETATION

In conclusion, perinatal malnutrition profoundly impairs the programming of beta-cell development. In animals with decreased beta-cell mass the additional demand placed by ageing on the beta cells entails glucose intolerance since beta-cell mass does not expand and apoptosis is increased.

Beta-cell mass and proliferation following late fetal and early postnatal malnutrition in the rat

We have recently shown that maternal food restriction during late pregnancy in rats decreased beta-cell mass in the offspring at birth, without altering beta-cell proliferation. The aim of the present work was to determine: 1) whether sustained maternal undernutrition until weaning (R group) more dramatically alters beta-cell mass in the offspring and if normal food supply from weaning until adulthood could reverse the deleterious effects and; 2) if altered beta-cell proliferation was responsible for the decreased beta-cell mass. Beta-cell fraction and proliferative capacity were determined during the suckling period and at adult age after ad libitum feeding from weaning in the R animals and in age-matched controls (C group). At day 21, the offspring born and nursed by food-restricted mothers (R animals) showed a 66% reduction in beta-cell mass and number, which did not increase from birth to weaning, although beta-cell proliferation remained normal. At 3 months of age, R animals had 35% decreased beta-cell fraction, with a 50% decrease in the head of the pancreas. In that area, beta-cell proliferation was similar to that of the controls. In the tail of the pancreas, beta-cell fraction was only slightly impaired but beta-cell proliferation was increased by 37%, as compared with the controls. This increase was associated with a shift in islet size distribution towards medium and large islets compared with the head of pancreas from these R animals. No regional variations of beta-cell fraction, proliferation or islet size distribution were observed in adult control animals. In conclusion, prolonged malnutrition until weaning impairs beta-cell development but not beta-cell proliferation. Subsequent re-nutrition is followed by increased beta-cell proliferation but this is insufficient to fully restore beta-cell mass.

In utero undernutrition impairs rat beta-cell development

The role of nutrition on the development of the endocrine pancreas was studied in a rat model obtained by maternal food restriction. A 50% food restriction was applied to female rats from day 15 of pregnancy and resulted in intrauterine growth-retardation (IUGR) in the offspring. At day 1 postnatal, beta-cell mass was significantly decreased in IUGR pups as compared to controls (0.70 +/- 0.06 vs 1.07 +/- 0.06 mg, p < 0.0001), as well as insulin content. This change in beta-cell mass can be attributed to a reduced number of islets, since the density of insulin-positive aggregates in pancreatic sections of IUGR rats was 20% lower than in controls. Proliferative capacity of beta cells, as measured by 5-bromo-2-deoxyuridine (BrdU) labelling index, was not altered in growth-retarded animals. Body as well as pancreatic weight were fully recovered in IUGR pups after 21 days of normal feeding by control mothers. However, these animals retained a 25% decrease in insulin content, 40% decrease in beta-cell mass (1.58 +/- 0.18 vs 2.78 +/- 0.42 mg, p < 0.001) and a strong reduction in the density of insulin positive aggregates per cm2, as compared to controls, suggesting that the total islet number was likely to be reduced. Beta-cell proliferative capacity remained normal. In conclusion, in utero undernutrition in rats does not impede postnatal growth but durably impairs beta-cell development. Impairment of beta-cell differentiation might be suggested.

Role of CCK in the regulation of secretion and adaptation in the pig pancreas

The effect of cholecystokinin (CCK) on the pancreas was investigated in the pig in two experiments. Fifteen pigs were fed a diet containing 17 or 48% protein with or without MK329 (4.5 mg per meal). MK329 enhanced the postprandial peak of plasma CCK during the first 30 min, but pancreas adaptation to high protein was not affected. Sixteen pigs were divided into two groups: 12 pigs were infused with CCK-8 + secretin for 1 h and four pigs received a standard meal. In both groups, pancreatic secretion tests were performed under infusion of the vehicle alone or with MK329. After CCK + secretin, MK329 (65-500 micrograms/kg/h) did not alter CCK plasma levels and reduced the early pancreatic protein response by about 30%. Enzyme outputs in pancreatic juice were modestly affected by MK329. After the meal, MK329 (500 micrograms/kg/h) doubled the postprandial peak of plasma CCK and lowered the pancreatic protein output by 35-40% for the first 30 min. We suggest that (a) pancreatic adaptation to high dietary protein is not mediated via CCK-A receptors and (b) the stimulation of pancreatic protein secretion by a meal or by exogenous CCK-8 is mediated partly by CCK-A receptors.