The degree of lipid peroxidation was measured in organs from diabetic rats receiving no treatment, and in those from insulin-treated diabetic rats and controls. Lipid peroxidation was measured as organ content of malondialdehyde, a degradation product of polyunsaturated fatty acids. In the kidney, lipid peroxidation was increased after one week of diabetes; insulin treatment reduced the level of lipid peroxidation to levels lower than seen in controls. In the liver, diabetes caused an increased lipid peroxidation, which could be reversed by insulin; no additional effect of insulin was found. In heart and pancreas no effects of diabetes or insulin were demonstrated. The present paper provides evidence that lipid peroxidation is increased in the early stages of experimental diabetes and is reversible by insulin treatment. Hyperinsulinaemia may, in itself, counteract lipid peroxidation in kidney.
Jørgen Rungby, Allan Flyvbjerg, Herdis B Andersen and Kirsten Nyborg
J. Östman, G. Lundgren, G. Tydén, R. Gunnarsson and C-G. Groth
Between December 1966 and June 1982, 269 transplantations of vascularized pancreas (whole or segmental) were undertaken in 254 diabetic patients throughout the world. Most of the transplantations were performed in patients with end-stage renal disease who also received kidney grafts; a few patients received pancreatic grafts only. About 25% of the pancreatic grafts are still functioning after periods of various lenghts, the longest being five years.
To the problem of how to handle the exocrine secretion there are two main approaches: 1) occlusion of the duct with a synthetic polymer and 2) pancreatico-enterostomy. A disadvantage of the former procedure is late fibrosis and atrophy of the endocrine tissue. With the latter method duct leakage and fistula development cannot be completely prevented. In either case, vascular complications cause graft failure in about 20% of the operations. The risk of rejection of the graft seems not to differ significantly from that concerning other allogeneic organs, including the kidney and heart.
Most of the patients with a functioning pancreatic graft are normoglycemic: they have a normal or near-normal oral or intravenous glucose tolerance and an early insulin response to intravenous glucose tolerance and an early insulin response to intravenous glucose challenge. Whether the improvement of the motor and sensory nerve conduction velocities observed in some patients whose graft has functioned for a long time is due to the reversal of renal insufficiency or to insulin deficiency cannot yet be determined. At present, pancreas transplantation at Huddinge Hospital is performed only in conjunction with renal transplantation in patients with end-stage diabetic renal disease.
The metabolic disturbances in animals with experimental or spontaneous diabetes mellitus can be corrected by the transplantation of either a vascularized pancreatic graft or a suspension of more or less purified islets. In insulin-dependent patients only vascularized pancreatic allografts have led to sustained normoglycemia; the results of transplanting suspensions of adult or fetal human pancreas have so far been discouraging (Sutherland, 1981b). This presentation will deal only with the transplantation of vascularized pancreatic allografts, which has proved increasingly successful in recent years. Since the first systematic clinical trial started in December, 1966, in Minnesota more than 300 pancreatic transplantations have been performed, according to the new Human Pancreas and Islet Transplant Registry (Sutherland, 1984). During the last few years the annual number of pancreas transplantations carried out in the world has greatly increased (Fig. 1), and more than 40 centers have now reported to the Registry.
Kazuo Yagui, Takahide Yamaguchi, Azuma Kanatsuka, Fumio Shimada, Choug I Huang, Yoshiharu Tokuyama, Haruhiko Ohsawa, Ken-ichi Yamamura, Jun-ichi Miyazaki, Atsuo Mikata, Sho Yoshida and Hideichi Makino
Yagui K, Yamaguchi T, Kanatsuka A, Shimada F, Huang CI, Tokuyama Y, Ohsawa H, Yamamura K, Miyazaki J. Mikata A, Yoshida S, Makino H. Formation of islet amyloid fibrils in beta-secretory granules of transgenic mice expressing human islet amyloid polypeptide/amylin. Eur J Endocrinol 1995:132:487–96. ISSN 0804–4643
To investigate the relationship between human islet amyloid polypeptide (IAPP)/amylin expression and islet amyloid deposits in the pathogenesis of human non-insulin-dependent diabetes mellitus (NIDDM), we developed transgenic mice using a human IAPP cDNA connected to an insulin promoter. Ribonucleic acid blotting and immunohistochemistry revealed the expression of the transgene in the pancreatic beta cells. Immunogold electron microscopy showed that beta-secretory granules contained the human C-terminal flanking peptide of the IAPP precursor. Reverse-phase HPLC demonstrated human and mouse IAPP amide in the pancreas. Electron microscopy showed the accumulation of fibril-like material in a considerable number of beta-secretory granules. These results suggest that in transgenic mice, the human IAPP precursor is expressed in beta cells and becomes normally sorted into beta-secretory granules in which normal conversion to mature human IAPP takes place. The human IAPP molecules, because of their amyloidogenesis, aggregate into amyloid fibrils in secretory granules. Glucose tolerance was normal at 7 months old and islet amyloid was not observed. A longer time may be required for islet amyloid deposits and hyperglycemia to develop in mice. Our working hypothesis is that in human NIDDM, IAPP aggregates into amyloid fibrils in beta-secretory granules, and that the fibrils are released into the extracellular space and islet amyloid deposits become substantial with time.
Azuma Kanatsuka, Second Department of Internal Medicine, Chiba University School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260, Japan
L. Verschoor, H. A. M. Hulsmans, J. de Gruyl, D. L. Westbroek and I. MacDicken
Pancreas transplantation was studied in the dog using a total duct ligated pancreas as allograft. In a group of 10 mongrel dogs the effects of longterm (6–36 months) total duct ligation on the endocrine pancreas function were studied by means of repeated intravenous glucose tolerance tests (iv-GTT). One year after total duct ligation the mean glucose assimilation coefficient (k-value) was 75%, the median insulin peak value (IPV) 63% and "total" insulin secretion in the first thirty minutes (TIS) 58 % of the pre-operative values. These levels were maintained up to three years after duct ligation.
The total duct ligated pancreas was then used as an allograft in 28 beagles in order to study the influence of DL-A (dog leucocyte-antigens) matching on the survival time of the graft. DL-A identity compared to one or two haplotype diference gave a fourfold increase in median survival time from 9 to 40 days. In a second group of 14 beagles with one haplotype difference the effect of immunosuppressive therapy was studied. The methods used (antilymphocyte serum and a combination of prednisone and azathioprine) increased the median survival time to the level seen in DL-A identity.
In conclusion the total duct ligated pancreas can be used as an insulin secreting allograft, providing rejection can be suppressed adequately.
H Hui and R Perfetti
Pancreas duodenum homeobox-1 (PDX-1) (also known as insulin promoter factor-1, islet/duodenum homeobox-1, somatostatin transactivating factor-1, insulin upstream factor-1 and glucose-sensitive factor) is a transcription factor encoded by a Hox-like homeodomain gene. In humans and other animal species, the embryonic development of the pancreas requires PDX-1, as demonstrated by the identification of an individual with pancreatic agenesis resulting from a mutation that impaired the transcription of a functionally active PDX-1 protein. In adult subjects, PDX-1 is essential for normal pancreatic islet function as suggested by its regulatory action on the expression of a number of pancreatic genes, including insulin, somatostatin, islet amyloid polypeptide, the glucose transporter type 2 and glucokinase. Furthermore, heterozygous mutations of PDX-1 have been linked to a type of autosomal dominant form of diabetes mellitus known as maturity onset diabetes of the young type 4. The dual action of PDX-1, as a differentiation factor during embryogenesis and as a regulator of islet cell physiology in mature islet cells, underscores the unique role of PDX-1 in health and disease of the human endocrine pancreas.
O. D. Bruno, Patricia Metzger and W. J. Malaisse
The effect of metyrapone on in vitro glucose metabolism in the rat muscle and brain, and on insulin secretion by the rat pancreas was investigated. In the presence of increasing concentrations of metyrapone ditartrate, there was a significant progressive reduction in glucose uptake by incubated hemidiaphragms and in the glucose uptake and oxidation by incubated brain pieces. The insulin output by incubated pieces of pancreas was also significantly inhibited by metyrapone ditartrate. A clear dose-action relationship is shown between the residual glucose uptake by the muscle and the uptake or oxidation of glucose by the brain on one hand, and the logarithm of the corresponding metyrapone ditartrate concentration on the other.
These data may help to explain some clinical and experimental findings, i. e. the simultaneous occurrence of hyperglycaemia, signs of cerebral dysfunction and also of growth hormone release after the administration of metyrapone in vivo.
O. Schmitz, K. G. M. M. Alberti and H. ørskov
Abstract. Twenty-four hour insulin requirements were measured in 5 uraemic insulin-dependent diabetics using a glucose controlled insulin infusion system (artificial endocrine pancreas). All patients were studied twice: initially 14 (1–27) days before institution of dialysis treatment and again after a mean of 46 (21–98) days on chronic dialysis therapy. At near normal blood glucose level the daily insulin requirements decreased from 44.8 ± 2.9 U pre-dialysis to 35.0 ± 2.3 U post-dialysis (P < 0.001). The reduction included the prandial as well as the basal requirements. Consistent with this, the mean plasma free insulin level was higher pre-dialysis than post-dialysis (42 ± 12μU/ml vs 31 ± 7μU/ml especially during daytime (49 ± 11μU/ml vs 37 ± 9 μU/ml, P < 0.03), suggesting that a decreased insulin degradation was not a major factor in the difference in insulin requirements. The effect of an acute change in azotaemia on insulin requirements was also evaluated in 4 uraemic diabetics on chronic haemodialysis the day prior to and the day after a routine dialysis (serum creatinine 922 ± 59μmol/l vs 555 ± 109μmol/l). No difference in insulin administration on the two days was observed (42.5 ± 6.1 U vs 43.2 ± 5.6 U). It is concluded that insulin resistance is present in uraemic insulin-dependent diabetics analogous to the insulin resistance widely prevalent in non-diabetic uraemic patients. The abnormality is at least partly reversible after several weeks on chronic dialysis, but not acutely. The pathophysiologic mechanisms underlying the insulin resistance in uraemia in the diabetic remain to be clarified.
Hitoshi Ishida, Yutaka Seino, Noritaka Takeshita, Takeshi Kurose, Kazuo Tsuji, Yoshimasa Okamoto, Yoshimichi Someya, Kuniko Hara, Yasuhiro Akiyama, Hiroo Imura and Masumi Nozawa
Diabetic osteopenia has been known as one of the chronic complications of diabetes mellitus, and a decrease in bone turnover has been thought to be one of the pathophysiological characteristics of this complication. In order to investigate the effect of long-term insulin therapy on low bone turnover in diabetes, pancreas transplantation was performed on streptozotocin-induced diabetic rats. Plasma levels of bone γ-carboxyglutamic acid-containing protein(osteocalcin) in untreated diabetic rats were 0.9±0.1 (mean±sem) nmol/l, significantly lower than the value of 4.2±0.6 nmol/l in control rats (p<0.01). Pancreas transplantation reversed this decrease to 6.3±1.1 nmol/l, which was not significantly different from the value in control rats. The circulating levels of calcitriol were significantly decreased in the untreated diabetic group (p<0.01), and the decrease was fully reversed by pancreas transplantation. In addition, the decreases in bone length, strength and weight were also improved by the transplantation. This evidence clearly shows that the improvement of metabolic derangements in diabetes by insulin is essential for the prevention of deterioration in diabetic osteopenia. It is possible, therefore, that insulin exerts an indirect beneficial influence through the metabolic amelioration on the decreases in bone turnover and circulating osteocalcin in diabetes mellitus, or has a direct stimulatory effect on the osteoblasts via the insulin receptor since its presence has been shown recently in osteoblastic cells.
J. Lindsten, E. Cerasi, R. Luft and G. Hultquist
The plasma insulin response to prolonged glucose infusion was studied in 14 patients with Turner's syndrome having a normal intravenous glucose tolerance test. The insulin response was in most instances delayed and diminished in spite of a higher than normal blood glucose level.
The fasting plasma growth hormone (HGH) level was elevated, and hyperglycaemia induced a paradoxical increase in plasma HGH in most of the patients. The HGH response to hypoglycaemia was normal.
Oestrogen replacement accentuated the paradoxical HGH reaction to hyperglycaemia while the insulin response diminished further.
In contrast to earlier studies no increase in the frequency of diabetes was found among the relatives of the Turner patients.
In one subject there was a definite hyperplasia of the islet tissue of the pancreas with signs of decreased activity of the β-cells, in a second one the amount of islet tissue was fairly high.
Possible relationships between the above findings are discussed.
Johannes Järhult, Lars-Ove Farnebo, Bertil Hamberger, Jens Holst and Thue W. Schwartz
The effects of insulin hypoglycaemia (0.15 IU/kg) on plasma adrenaline, noradrenaline, dopamine, glucagon and pancreatic polypeptide (PP) concentrations were investigated in 6 adrenalectomized subjects and 6 healthy controls. Both the rise in mean plasma insulin and the fall in mean blood glucose concentration were closely similar in the two groups. Mean plasma adrenaline concentration rose by about 3 nmol/l in the normal subjects, but remained unchanged in adrenalectomized subjects. Mean plasma noradrenaline concentration increased by about 2 nmol/l in both groups. Despite the large difference in adrenaline concentrations during hypoglycaemia, there was no significant difference between the responses of the endocrine pancreas of the normal and adrenalectomized subjects. Thus, mean plasma glucagon concentration rose by about 30 pmol/l and mean plasma PP concentration by about 150 pmol/l in each group. We conclude that the release of glucagon and PP during hypoglycaemia does not depend upon changes in plasma adrenaline concentration in man.