| 1. |
- Abrahamsson, Niclas, 1976-
(författare)
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On the Impact of Bariatric Surgery on Glucose Homeostasis
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity has grown to epidemic proportions, and in lack of efficient life-style and medical treatments, the bariatric surgeries are performed in rising numbers. The most common surgery is the Gastric Bypass (GBP) surgery, with the Biliopancreatic diversion with duodenal switch (DS) as an option for the most extreme cases with a BMI>50 kg/m2.In paper I 20 GBP-patients were examined during the first post-operative year regarding the natriuretic peptide, NT-ProBNP, which is secreted from the cardiac ventricles. Levels of NT-ProBNP quickly increased during the first post-surgery week, and later established itself on a higher level than pre-surgery.In paper II we report of 5 patient-cases after GBP-surgery with severe problems with postprandial hypoglycaemia that were successfully treated with GLP-1-analogs. The effect of treatment could be observed both symptomatically and in some cases using continuous glucose measuring systems (CGMS).In paper III three groups of subjects; 15 post-GBP patients, 15 post-DS, and 15 obese controls were examined for three days using CGMS during everyday life. The post-GBP group had high glucose variability as measured by MAGE and CONGA, whereas the post-DS group had low variability. Both post-operative groups exhibited significant time in hypoglycaemia, about 40 and 80 minutes per day <3.3mmol/l and 20 and 40 minutes < 2.8mmol/l, respectively, longer time for DS-group. Remarkably, only about 20% of these hypoglycaemic episodes were accompanied with symptoms.In Paper IV the hypoglycaemia counter regulatory system was investigated; 12 patients were examined before and after GBP-surgery with a stepped hypoglycaemic hyperinsulinemic clamp. The results show a downregulation of symptoms, counter regulatory hormones (glucagon, cortisol, epinephrine, norepinephrine, growth hormone), incretin hormones (GLP-1 and GIP), and sympathetic nervous response.In conclusion patients post bariatric surgery exhibit a downregulated counter regulatory response to hypoglycaemia, accompanied by frequent asymptomatic hypoglycaemic episodes in everyday life. Patients suffering from severe hypoglycaemic episodes can often be treated successfully with GLP-1-analogues.
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| 2. |
- Edén Engström, Britt
(författare)
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Growth Hormone and Gender. Studies in Healthy Adults and in Patients with Growth Hormone Disorders
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of a new, more sensitive immunoassay for growth hormone (GH) revealed that the serum levels in men were lower than expected in sera drawn ambulatory in the morning after an overnight fast and that the gender difference was more than 10 times greater than reported. These observations led to a more thorough study on the impact of gender and sex steroids on the levels of GH and other hormones in ambulatory morning samples and over a 24-hour period. Furthermore, the impact of gender was studied in GH deficient (GHD) patients and healthy young adults treated with GH, and in patients with acromegaly treated with octreotide. An 80-fold gender difference in the morning GH levels was observed in young individuals as a reaction to ambulation, with decreased levels in men and increased in women. Oral contraceptives (OCs) given to women further increased the morning GH levels. During the day, higher outputs of epinephrine and lower levels of GH were seen in the men, while no gender differences were seen at night. The gender difference in morning GH levels decreased with age due to opposite changes in men and women. Administration of 17β-estradiol (E2) via subcutaneous implants in postmenopausal women, which increased the E2-concentrations to luteal phase levels, had no effect on the morning GH levels, indicating that the different reactions to ambulation do not appear to result from a direct sex steroid effect alone. Short-term administration of GH to young, healthy adults resulted in larger effects on insulin-like growth factor I (IGF-I) and other key metabolic parameters in men than in women. The smallest response was noted in women taking OCs. The clinical studies involving long-term GH treatment of patients with GHD demonstrate a gender difference in GH responsiveness, with women being less sensitive than men, a fact which should have a therapeutic impact in patients with GH disorders. A further gender difference of therapeutic importance was observed in men and women with acromegaly. Long-term treatment with a slow-release formulation of octreotide resulted in higher IGF-I levels in the men, despite equal doses of the drug and similar levels of GH.
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| 3. |
- Holdstock, Camilla, 1975-
(författare)
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Gastric Bypass in Morbid Obesity : Postoperative Changes in Metabolic, Inflammatory and Gut Regulatory Peptides
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis examines the effect of surgical weight loss on gut and adipose tissue peptides involved in appetite regulation and energy homeostasis in morbidly obese humans. Roux-en-Y gastric bypass (RYGBP) is the gold standard operation used for effective long-term weight loss and improved health. The exact mechanisms for this outcome are under investigation.We measured ghrelin, a recently discovered hunger hormone, insulin, adiponectin and leptin along with anthropometry measures in 66 morbidly obese patients prior to and 6 and 12 months after RYGBP. Impressive weight loss occurred postoperatively as did alterations in the peptides. Consistent correlations were found between weight, leptin, ghrelin and insulin. The main findings were low ghrelin concentrations in obesity and an increase after RYGBP.We explored inflammatory proteins C-reactive protein (CRP), serum amyloid A and interleukin-6 before and during massive weight loss 6 and 12 months after RYGBP in morbidly obese subjects. The studied proteins declined after surgery and a correlation between CRP and homeostatic model of assessment for insulin resistance, independent of BMI, strongly linked insulin resistance and inflammation. CRP declined most in insulin-sensitive subjects.We examined the excluded stomach mucosa and vagus nerve by measuring gastrin, pepsinogen I (PGI), pancreatic polypeptide (PP) and ghrelin levels during week 1 and year after RYGBP. Ghrelin levels rose with weight loss but declined 24-hours after surgery, like PP, indicating transient vagal nerve damage. Low levels of gastrin and PGI suggest a resting mucosa.We evaluated gut peptides: peptide YY (PYY), glucaogon like peptide-1 (GLP-1), pro-neurotensin (pro-NT) and PP, in lean (young and middle-aged), obese and postoperative RYGBP subjects pre- and postprandially. RYGBP subjects had exaggerated levels of PYY and GLP-1 postprandially and higher basal proNT levels, implying a ‘satiety peptide tone’ that may contribute to the maintenance of weight loss.In summary, RYGBP results in marked weight loss and alterations in gut and adipose tissue peptides involved in appetite regulation and energy homeostasis. These postoperative peptide changes may contribute to impressive weight loss observed after RYGBP.
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| 4. |
- Rosén, Thord, et al.
(författare)
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Traumatisk hjärnskada kan ge hypofyssvikt : Förslag till riktlinjer för utvärdering av hypofysfunktionen
- 2012
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Ingår i: Läkartidningen. - : Läkartidningen förlag AB. - 0023-7205 .- 1652-7518. ; 109:12, s. 629-632
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Traumatisk hjärnskada (traumatic brain injury, TBI) är en av de vanligaste orsakerna till död och nedsatt funktion hos människor i arbetsför ålder. Patienter som överlever svåra skallskador utgör en växande patientkategori inom dagens sjukvård. På senare år har det aktualiserats att allvarligt skalltrauma kan ge skador i hypofys–hypotalamusregionen. Det är angeläget att dessa patienter utreds för eventuell hypofyssvikt så att hormonell substitutionsterapi kan inledas om endokrin insufficiens fastställs. Detta kan förhoppningsvis underlätta efterföljande rehabilitering och därmed förbättra prognosen. Vi presenterar här ett förslag till riktlinjer för utvärdering av hypofysfunktionen hos TBI-patienter. Samtidigt vill vi informera en bredare läsekrets om TBI-begreppet.
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