Sphingosine-1-phosphate lyase (SGPL1) deficiency is associated with mitochondrial dysfunction

Deficiency in Sphingosine-1-phosphate lyase (S1P lyase) is associated with a multi-systemic disorder incorporating primary adrenal insufficiency (PAI), steroid resistant nephrotic syndrome and neurological dysfunction. Accumulation of sphingolipid intermediates, as seen with loss of function mutations in SGPL1, has been implicated in mitochondrial dysregulation, including alterations in mitochondrial membrane potentials and initiation of mitochondrial apoptosis. For the first time, we investigate the impact of S1P lyase deficiency on mitochondrial morphology and function using patient-derived human dermal fibroblasts and CRISPR engineered SGPL1-knockout HeLa cells. Reduced cortisol output in response to progesterone stimulation was observed in two patient dermal fibroblast cell lines. Mass spectrometric analysis of patient dermal fibroblasts revealed significantly elevated levels of sphingosine-1-phosphate, sphingosine, ceramide species and sphingomyelin when compared to control. Total mitochondrial volume was reduced in both S1P lyase deficient patient and HeLa cell lines. Mitochondrial dynamics and parameters of oxidative phosphorylation were altered when compared to matched controls, though differentially across the cell lines. Mitochondrial dysfunction may represent a major event in the pathogenesis of this disease, associated with severity of phenotype.

International league of associations for rheumatology recommendations for the management of psoriatic arthritis in resource-poor settings

Background

Psoriatic arthritis (PsA) is a challenging heterogeneous disease. The European League Against Rheumatism (EULAR) and the Group for Research and Assessment of Psoriasis and PsA (GRAPPA) last published their respective recommendations for the management of PsA in 2015. However, these guidelines are primarily based on studies conducted in resource replete countries and may not be applicable in countries in the Americas (except Canada and USA) and Africa. We sought to adapt the existing recommendations for these regions under the auspices of the International League of Associations for Rheumatology (ILAR).

Process

The ADAPTE Collaboration (2009) process for guideline adaptation was followed to adapt the EULAR and GRAPPA PsA treatment recommendations for the Americas and Africa. The process was conducted in three recommended phases: set-up phase; adaptation phase (defining health questions, assessing source recommendations, drafting report), and finalization phase (external review, aftercare planning, and final production).

Result

ILAR recommendations have been derived principally by adapting the GRAPPA recommendations, additionally, EULAR recommendations where appropriate and supplemented by expert opinion and literature from these regions. A paucity of data relevant to resource-poor settings was found in PsA management literature.

Conclusion

The ILAR Treatment Recommendations for PsA intends to serve as reference for the management of PsA in the Americas and Africa. This paper illustrates the experience of an international working group in adapting existing recommendations to a resource-poor setting. It highlights the need to conduct research on the management of PsA in these regions as data are currently lacking.

Key Points • The paper presents adapted recommendations for the management of psoriatic arthritis in resource-poor settings. • The ADAPTE process was used to adapt existing GRAPPA and EULAR recommendations by collaboration with practicing clinicians from the Americas and Africa. • The evidence from resource-poor settings to answer clinically relevant questions was scant or non-existent; hence, a research agenda is proposed.

Electronic supplementary material

The online version of this article (10.1007/s10067-020-04934-7) contains supplementary material, which is available to authorized users.

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

BACKGROUND

The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications.

METHODS

ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery.

RESULTS

The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784.

CONCLUSIONS

This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance.

CLINICAL TRIAL REGISTRATION

NCT03044899.

Brain-derived neurotrophic factor and substrate utilization following acute aerobic exercise in obese individuals

Brain-derived neurotrophic factor (BDNF) serves as a vital regulator of neuronal proliferation and survival, and has been shown to regulate energy homeostasis, glucose metabolism and body weight maintenance. Elevated concentrations of plasma BDNF have been associated with obesity and type 2 diabetes mellitus. Acute aerobic exercise transiently increases circulating BDNF, potentially correcting obesity-related metabolic impairment. The present study aimed to compare acute aerobic exercise elicited BDNF responses in obese and normal-weight subjects. Furthermore, we aimed to investigate whether acute exercise-induced plasma BDNF elevations would be associated with improved indices of insulin resistance, as well as substrate utilization [carbohydrate oxidation (CHOoxi) and fat oxidation (FAToxi)]. Twenty-two healthy, untrained subjects [11 obese (four men and seven women; age = 22.91 ± 4.44 years; body mass index = 35.72 ± 4.17 kg/m(2)) and 11 normal-weight (five men and six women; age = 23.27 ± 2.24 years; body mass index = 21.89 ± 1.63 kg/m(2))] performed 30 min of continuous submaximal aerobic exercise at 75% maximal oxygen consumption. Our analyses showed that the BDNF response to acute aerobic exercise was similar in obese and normal-weight subjects across time (time: P = 0.015; group: P = not significant) and was not associated with indices of IR. Although no differences in the rates of CHOoxi and FAToxi were found between both groups, total relative energy expenditure was significantly lower in obese subjects compared to normal-weight subjects (3.53 ± 0.25 versus 5.59 ± 0.85; P < 0.001). These findings suggest that acute exercise-elicited BDNF elevation may not be sufficient to modulate indices of IR or the utilization of either carbohydrates or fats in obese individuals.

Ectopic expression of glucagon receptor in skeletal muscles improves glucose homeostasis in a mouse model of diabetes

AIMS/HYPOTHESIS

Excessive secretion of glucagon partially contributes to the development of diabetic hyperglycaemia. However, complete blocking of glucagon action will lead to adverse effects, since glucagon exerts certain beneficial effects via its receptor in many organs. We aimed to study the effects of a 'decoy receptor' for circulating glucagon on modulating beta cell function and glucose homeostasis in mice by over-producing the glucagon receptor (GCGR) in skeletal muscles.

METHODS

We generated transgenic mice in which the expression of Gcgr is driven by the muscle specific creatine kinase (Mck) promoter, and assessed the effects of glucagon on the modulation of glucose homeostasis under conditions of extremes of glucose influx or efflux.

RESULTS

Mck/Gcgr mice showed increased circulating levels of glucagon and insulin, resulting in an unchanged ratio of glucagon-to-insulin. The levels of hepatic glucose-6-phosphatase (G6PC) and fructose-1,6-bisphosphatase (F1,6P2ase) were significantly decreased, whereas the phosphorylation level of pancreatic cAMP-response-element-binding-protein (CREB) was significantly increased in these transgenic mice. Under basal conditions, the mice displayed normal blood glucose levels and unchanged glucose tolerance and insulin sensitivity when compared with their age-matched wild-type (WT) littermates. However, following multiple low-dose streptozotocin injections, Mck/Gcgr mice exhibited a delay in the onset of hyperglycaemia compared with the WT controls. This was associated with preserved beta cell mass and beta cell secretory capacity in response to glucose challenge.

CONCLUSIONS/INTERPRETATION

We suggest that mild and chronic hyperglucagonaemia, through a strategy involving neutralising peripheral glucagon action, provides beneficial effects on beta cell function and glucose homeostasis. Mck/Gcgr mice thus represent a novel mouse model for studying the physiological effects of glucagon.

Odontogenic Keratocyst in Jamaica: a review of five new cases and five instances of recurrence together with comparative analyses of four treatment modalities

AIM

Five new cases of odontogenic keratocyst (OKC) together with five instances of recurrence are reviewed with special emphasis on radiology and surgical management. A comparative analysis offour different treatment modalities used in the treatment of OKC in these patients (new and recurrent cases) is reported.

SUBJECTS AND METHODS

The case notes and radiographs ofpatients who had histological confirmation of OKC at both the Cornwall Regional Hospital and Kingston Public Hospital in Jamaica were reviewed for demographics, radiological presentation, treatment modalities and outcome of treatment. Cases of recurrence were separated from new cases. This study was conducted for the period 1980 to 2004.

RESULTS

Five new cases and five instances of recurrence were documented over the 25-year period The new cases of OKC keratocyst accounted for 1.71% of the total jaw bone tumours and 12% of OKC keratocysts over the first 16 years. The posterior mandible appears to be the most favoured site. Of significance, one case of nevoid basal cell carcinoma syndrome (NBCCS) and a case of ameloblastomatous transformation in the wall of an OKC keratocyst were recorded The age range of the new cases was 12 to 44 years.

CONCLUSION

The radiological finding from this review is similar to previous reports. However the authors record a unique and historic case of ameloblastomatous transformation of OKC. A case of OKC in NBCCS is also documented Of all four surgical treatment modalities compared, only cryosurgery was promising, so far with no recurrence after a follow-up period of six years.

Partial decapsulation of splenic epithelial cysts: studies on etiology and outcome

PURPOSE

The presence of squamous epithelium in the cyst wall of children with large splenic cysts has generally been thought to require complete resection of the cyst lining to prevent recurrence. The risks of major bleeding or possible total splenectomy necessitates a simplified procedure to preserve splenic function without cyst recurrence.

METHODS

Six patients treated for splenic cyst over a 10-year period underwent partial splenic decapsulation retaining the hilar portion of the spleen. The patient group, including five girls, ranged in age from 6 to 18 years (mean, 13 years). Presenting findings were splenomegaly (n = 4), progressive cyst enlargement (n = 4), left upper quadrant pain (n = 2), ultrasound for unrelated condition (n = 2), and prior history of trauma (n = 1). Cyst location varied from peripheral to deep cortical and ranged in size from 5 to 20 cm containing from 200 to 1,700 mL of sterile straw-colored to dark brown-colored liquid.

RESULTS

Palpable splenomegaly resolved in all patients with progressive decrease in size of the splenic remnant, and return of vascularity to normal was confirmed by Doppler ultrasound. Each patient remains asymptomatic without recurrence of the splenic cyst from 1 to 10 years after surgery. Squamous epithelial lining cells found in sheets and clusters were seen within the cyst lining of all patients. Immunohistochemistry of the paraffin-embedded tissue showed that these cells expressed keratin, epithelial membrane antigen (EMA), carcino-embryonic antigen (CEA), but were negative for BerEP4 (conventionally positive in cells of epithelial origin).

CONCLUSION

The authors conclude that splenic decapsulation is an effective treatment for splenic epithelial cysts, which both preserves splenic function and prevents recurrence despite retention of hilar cyst lining. Epithelial metaplasia of the mesothelial-mesodermal undifferentiated cells from exposure to an unidentified irritant may explain the histological presence of squamous epithelium within the cyst wall.