Mice fed a high-fat, low-carbohydrate ketogenic diet (KD) exhibit marked changes in hepatic metabolism and energy homeostasis. Here, we identify liver-derived fibroblast growth factor 21 (FGF21) as an endocrine regulator of the ketotic state. Hepatic expression and circulating levels of FGF21 are induced by both KD and fasting, are rapidly suppressed by refeeding, and are in large part downstream of PPARalpha. Importantly, adenoviral knockdown of hepatic FGF21 in KD-fed mice causes fatty liver, lipemia, and reduced serum ketones, due at least in part to altered expression of key genes governing lipid and ketone metabolism. Hence, induction of FGF21 in liver is required for the normal activation of hepatic lipid oxidation, triglyceride clearance, and ketogenesis induced by KD. These findings identify hepatic FGF21 as a critical regulator of lipid homeostasis and identify a physiological role for this hepatic hormone.

Background & Aims Fibroblast growth factor 21 (FGF21) is a hepatic protein that plays a critical role in metabolism, stimulating fatty acid oxidation in liver and glucose uptake in fat. Systemic administration to obese rodents and diabetic monkeys leads to improved glucose homeostasis and weight loss. In rodents, FGF21 increases with fasting and consumption of a ketogenic diet (KD). In humans, FGF21 correlates with body mass index, but studies evaluating other parameters show inconsistent results. We examined FGF21 serum levels in lean and obese individuals and in response to dietary manipulation. We also evaluated FGF21 serum levels and liver mRNA expression in nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Methods Serum FGF21 was measured after an overnight fast in individuals with BMI ranging from normal to obese. Volunteers fasted for 16 or 72 hours and then ate a standard meal. Another group consumed KD for 12 days. Serum FGF21 and hepatic mRNA expression were measured in obese individuals with NAFLD or NASH. Results There was a positive correlation between BMI and FGF21. There was no change in FGF21 in response to a short fast or KD. A non-statistically significant fall in FGF21 levels was seen after a 72 hour fast. Hepatic FGF21 mRNA expression was significantly elevated in NAFLD, which correlated with a substantial increase in serum FGF21. In NASH, serum FGF21 but not liver mRNA was increased. Conclusion FGF21 correlates with BMI and may be a novel biomarker for NAFLD but is not nutritionally regulated in humans.

The multifactorial mechanisms promoting weight loss and improved metabolism following Roux-en-Y gastric bypass (GB) surgery remain incompletely understood. Recent rodent studies suggest that bile acids can mediate energy homeostasis by activating the G-protein coupled receptor TGR5 and the type 2 thyroid hormone deiodinase. Altered gastrointestinal anatomy following GB could affect enterohepatic recirculation of bile acids. We assessed whether circulating bile acid concentrations differ in patients who previously underwent GB, which might then contribute to improved metabolic homeostasis. We performed cross-sectional analysis of fasting serum bile acid composition and both fasting and post-meal metabolic variables, in three subject groups: (i) post-GB surgery (n = 9), (ii) without GB matched to preoperative BMI of the index cohort (n = 5), and (iii) without GB matched to current BMI of the index cohort (n = 10). Total serum bile acid concentrations were higher in GB (8.90 ± 4.84 µmol/l) than in both overweight (3.59 ± 1.95, P = 0.005, Ov) and severely obese (3.86 ± 1.51, P = 0.045, MOb). Bile acid subfractions taurochenodeoxycholic, taurodeoxycholic, glycocholic, glycochenodeoxycholic, and glycodeoxycholic acids were all significantly higher in GB compared to Ov (P < 0.05). Total bile acids were inversely correlated with 2-h post-meal glucose (r = −0.59, P < 0.003) and fasting triglycerides (r = −0.40, P = 0.05), and positively correlated with adiponectin (r = −0.48, P < 0.02) and peak glucagon-like peptide-1 (GLP-1) (r = 0.58, P < 0.003). Total bile acids strongly correlated inversely with thyrotropic hormone (TSH) (r = −0.57, P = 0.004). Together, our data suggest that altered bile acid levels and composition may contribute to improved glucose and lipid metabolism in patients who have had GB.

In addition to digesting and assimilating nutrients, the intestine and associated visceral organs play a key sensing and signaling role in the physiology of energy homeostasis. The gut, the pancreatic islets of Langerhans, elements in the portal vasculature, and even visceral adipose tissue communicate with the controllers of energy balance in the brain by means of neural and endocrine pathways. Signals reflecting energy stores, recent nutritional state, and other parameters are integrated in the central nervous system, particularly in the hypothalamus, to coordinate energy intake and expenditure. Our understanding of regulatory neural circuits and the signaling molecules that influence them has progressed rapidly, particularly after the discovery of the adipocyte hormone leptin. These discoveries have led to exploration of novel routes for obesity control, some of which involve gut-derived pathways.

Elevation of plasma concentrations of kisspeptin in human males significantly increases circulating LH, FSH, and testosterone levels. Kisspeptin infusion provides a novel mechanism for hypothalamic-pituitary-gonadal axis manipulation in disorders of the reproductive system.

Fibroblast growth factor 21 (FGF21) is a key metabolic regulator. Expressed primarily in liver and adipose tissue, FGF21 is induced via peroxisome proliferator-activated receptor (PPAR) pathways during states requiring increased fatty acid oxidation including fasting and consumption of a ketogenic diet. To test the hypothesis that FGF21 is a physiological regulator that plays a role in lipid oxidation, we generated mice with targeted disruption of the Fgf21 locus (FGF21 knockout). Mice lacking FGF21 had mild weight gain and slightly impaired glucose homeostasis, indicating a role in long-term energy homeostasis. Furthermore, FGF21KO mice tolerated a 24-h fast, indicating that FGF21 is not essential in the early stages of starvation. In contrast to wild-type animals in which feeding KD leads to dramatic weight loss, FGF21KO mice fed KD gained weight, developed hepatosteatosis, and showed marked impairments in ketogenesis and glucose control. This confirms the physiological importance of FGF21 in the adaptation to KD feeding. At a molecular level, these effects were accompanied by lower levels of expression of PGC1alpha and PGC1beta in FGF21KO mice, strongly implicating these key transcriptional regulators in the action of FGF21. Furthermore, within the liver, the maturation of the lipogenic transcription factor sterol regulatory element-binding protein-1c was increased in FGF21KO mice, implicating posttranscriptional events in the maladaptation of FGF21KO mice to KD. These data reinforce the role of FGF21 is a critical regulator of long-term energy balance and metabolism. Mice lacking FGF21 cannot respond appropriately to a ketogenic diet, resulting in an impaired ability to mobilize and utilize lipids.

Vesicovaginal fistulas-vault fistulas as they are called when located at the vaginal apex following total hysterectomy-are rare lesions that are located on the anterior vaginal wall just in front of the transverse vaginal scar made when the cervix is removed. Latzko, in 1942, described a technique of treating vault fistulas solely through a vaginal approach. A vault colpocleisis is performed without attempting to dissect the fistulous tract. Although this is an effective and relatively simple procedure, there is as yet no consensus on first-line treatment of these lesions. The authors report the results of the Latzko procedure in 11 women with a mean age of 50 years who had a postoperative vesicovaginal fistula. All but one of the fistulas followed total hysterectomy. The mean interval between primary surgery and a fistula was just short of 2 weeks. Urethral bladder drainage for 5-8 days did not prevent a fistula from forming in these patients.Urinary drainage was maintained for at least 6 weeks before surgical repair. The fistula was drawn downward using a balloon catheter placed in its opening and was then circumcised 1.5 to 2 cm from the opening. All epithelium from the circumcised area to the edge of the fistula's opening was removed before approximating the anterior and posterior vaginal walls using interrupted absorbable sutures. The vaginal mucosa then was closed by a second layer of sutures. The bladder was drained with a Foley catheter until the cystogram was normal.The Latzko procedure succeeded in all cases as evidenced by the absence of urine loss during a bladder tightness test 1 month postoperatively. There were no intraoperative complications, and the only postoperative problem was a lower urinary tract infection. The patients were followed for a mean of 19 months after repair. These results show that the Latzko procedure is a safe, technically simple, and effective means of treating vault vesicovaginal fistulas. The investigators recommend it as the most appropriate first-line surgical treatment. GYNECOLOGYVolume 62, Number 1 OBSTETRICAL AND GYNECOLOGICAL SURVEY ABSTRACTObjective cure rates exceeding 75% are reported after colposuspension in women with stress incontinence, but extended follow-up has not been the rule. Small-scale studies also have been done to evaluate laparoscopic colposuspension after its introduction in 1991. A Cochrane review in the year 2000 yielded no conclusions about the long-term efficacy of this procedure.The present randomized controlled trial recruited, from six gynecology units in the United Kingdom, 291 women with proven stress urinary incontinence who required surgery. Participants were randomized to undergo open abdominal retropubic colposuspension or laparoscopic colposuspension. Subjective outcomes were based on patient satisfaction, and objective outcomes on a negative 1-hour pad test. Data on objective outcomes were available after 2 years of follow-up in 85% of women having laparoscopic surgery and 80% of those having open surgery. The respective figures for s...

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