Zinc exocytosis is sensitive to myosin light chain kinase inhibition in mouse and human eggs

Zinc dynamics are essential for oocyte meiotic maturation, egg activation, and preimplantation embryo development. During fertilisation and egg activation, the egg releases billions of zinc atoms (Zn2+) in an exocytotic event termed the 'zinc spark'. We hypothesised that this zinc transport and exocytosis is dependent upon the intracellular trafficking of cortical granules (CG) which requires myosin-actin-dependent motors. Treatment of mature mouse and human eggs with ML-7, a myosin light chain kinase inhibitor (MLCK), resulted in an 80% reduction in zinc spark intensity compared to untreated controls when activated with ionomycin. Moreover, CG migration towards the plasma membrane was significantly decreased in ML-7-treated eggs compared with controls when activated parthenogenetically with ionomycin. In sperm-induced fertilisation via intracytoplasmic sperm injection (ICSI), ML-7-treated mouse eggs exhibited decreased labile zinc intensity and cortical CG staining. Collectively, these data demonstrate that ML-7 treatment impairs zinc release from both murine and human eggs after activation, demonstrating that zinc exocytosis requires myosin light chain kinase activity. Further, these results provide additional support that zinc is likely stored and released from CGs. These data underscore the importance of intracellular zinc trafficking as a crucial component of egg maturation necessary for egg activation and early embryo development.

Extra Cellular Matrix-Based and Extra Cellular Matrix-Free Generation of Murine Testicular Organoids

Testicular organoids provide a tool for studying testicular development, spermatogenesis, and endocrinology in vitro. Several methods have been developed in order to create testicular organoids. Many of these methods rely upon extracellular matrix (ECM) to promote de novo tissue assembly, however, there are differences between methods in terms of biomimetic morphology and function of tissues. Moreover, there are few direct comparisons of published methods. Here, a direct comparison is made by studying differences in organoid generation protocols, with provided outcomes. Four archetypal generation methods: (1) 2D ECM-free, (2) 2D ECM, (3) 3D ECM-free, and (4) 3D ECM culture are described. Three primary benchmarks were used to assess the testicular organoid generation. These are cellular self-assembly, inclusion of major cell types (Sertoli, Leydig, germ, and peritubular cells), and appropriately compartmentalized tissue architecture. Of the four environments tested, 2D ECM and 3D ECM-free cultures generated organoids with internal morphologies most similar to native testes, including the de novo compartmentalization of tubular versus interstitial cell types, the development of tubule-like-structures, and an established long-term endocrine function. All methods studied utilized unsorted, primary murine testicular cell suspensions and used commonly accessible culture resources. These testicular organoid generation techniques provide a highly accessible and reproducible toolkit for research initiatives into testicular organogenesis and physiology in vitro.

Testicular organoid formation is a property of immature somatic cells, which self-assemble and exhibit long-term hormone-responsive endocrine function

Testicular organoid models are tools to study testicular physiology, development, and spermatogenesis in vitro. However, few side-by-side comparisons of organoid generation method have been evaluated. Here, we directly tested whether the culture microenvironment is the prime determinant promoting testicular organoid self-assembly. Using Matrigel as a representative extracellular matrix (ECM), we compared multiple culture environments, 2D and 3D, ECM-free and ECM, for organoid self-assembly with immature murine testicular cells. De novo tissues were observed to self-assemble in all four culture environments tested within 72 h, however, these tissues only met requirements to be named organoids in 2D ECM and 3D ECM-free (3DF) culture methods. Based on these results, 3DF was selected for further study, and used to examine animal age as an independent variable. Organoid assembly was significantly delayed when using pubertal murine cells and entirely absent from adult murine and adult human cells. Organoid-conditioned medium and medium supplemented with 1% Matrigel did not improve organoid assembly in pubertal murine cells, but immature murine cells rescued the assembly of adult murine cells when cultured together as age-chimeric cell mixtures. In murine organoids cultured for 14 d, tubule-like structures exhibiting a highly biomimetic architecture were characterized, including some rare germ and spermatogonial stem cells. These structural organoids secreted high levels of testosterone and inhibin B over 12 weeks with preserved responsivity to gonadotropins. Collectively these studies, in which cellular self-assembly and organoid formation was achieved independent of the culture microenvironment, suggest that self-assembly is an innate property of immature testicular cells independent from, but capable of being promoted by, the culture environment. This study provides a template for studying testicular organoid self-assembly and endocrine function, and a platform for improving the engineering of functional testicular tissues.

Engineered reproductive tissues

Engineered male and female biomimetic reproductive tissues are being developed as autonomous in vitro units or as integrated multi-organ in vitro systems to support germ cell and embryo function, and to display characteristic endocrine phenotypic patterns, such as the 28-day human ovulatory cycle. In this Review, we summarize how engineered reproductive tissues facilitate research in reproductive biology, and overview strategies for making engineered reproductive tissues that might eventually allow the restoration of reproductive capacity in patients.

Survey of Fertility Preservation Options Available to Patients With Cancer Around the Globe

Oncofertility focuses on providing fertility and endocrine-sparing options to patients who undergo life-preserving but gonadotoxic cancer treatment. The resources needed to meet patient demand often are fragmented along disciplinary lines. We quantify assets and gaps in oncofertility care on a global scale.

Survey of Third-Party Parenting Options Associated With Fertility Preservation Available to Patients With Cancer Around the Globe

In the accompanying article, “Survey of Fertility Preservation Options Available to Patients With Cancer Around the Globe,” we showed that specific fertility preservation services may not be offered at various sites around the world because of cultural and legal barriers. We assessed global and regional experiences as well as the legal status of third-party reproduction and adoption to serve as a comprehensive international data set and resource for groups that wish to begin oncofertility interventions.

Infrared thermography and ulcer prevention in the high-risk diabetic foot: data from a single-blind multicentre controlled clinical trial

AIM

To assess the usefulness of monthly thermography and standard foot care to reduce diabetic foot ulcer recurrence.

METHODS

People with diabetes (n = 110), neuropathy and history of ≥ 1 foot ulcer participated in a single-blind multicentre clinical trial. Feet were imaged with a novel thermal imaging device (Diabetic Foot Ulcer Prevention System). Participants were randomized to intervention (active thermography + standard foot care) or control (blinded thermography + standard foot care) and were followed up monthly until ulcer recurrence or for 12 months. Foot thermograms of participants from the intervention group were assessed for hot spots (areas with temperature ≥ 2.2°C higher than the corresponding contralateral site) and acted upon as per local standards.

RESULTS

After 12 months, 62% of participants were ulcer-free in the intervention group and 56% in the control group. The odds ratios of ulcer recurrence (intervention vs control) were 0.82 (95% CI 0.38, 1.8; P = 0.62) and 0.55 (95% CI 0.21, 1.4; P = 0.22) in univariate and multivariate logistic regression analyses, respectively. The hazard ratios for the time to ulcer recurrence (intervention vs control) were 0.84 (95% CI 0.45, 1.6; P = 0.58) and 0.67 (95% CI 0.34, 1.3; P = 0.24) in univariate and multivariate Cox regression analyses, respectively.

CONCLUSIONS

Monthly intervention with thermal imaging did not result in a significant reduction in ulcer recurrence rate or increased ulcer-free survival in this cohort at high risk of foot ulcers. This trial has, however, informed the design of a refined study with longer follow-up and group stratification, further aiming to assess the efficacy of thermography to reduce ulcer recurrence.

Inhibitors of apoptosis protect the ovarian reserve from cyclophosphamide

Cancer therapy can cause off-target effects including ovarian damage, which may result in primary ovarian insufficiency in girls and premenopausal women. Loss of ovarian follicles within the ovarian reserve leads to ovarian endocrine dysfunction and impaired fertility. Cyclophosphamide (CPA), a commonly used chemotherapeutic and immunosuppressant agent, is a gonadotoxic agent that destroys ovarian cells by crosslinking DNA. To protect the ovary against CPA damage, we sought to precisely map the mechanism by which the ovarian reserve is depleted by CPA. We found that CPA specifically depletes primordial follicles without affecting primary and secondary follicles in three independent murine strains (CD-1, C57BL/6J and BALB/cJ) in vivo. We directly tested the effect of the active metabolite of CPA, 1 μM 4-hydroxyperoxycyclophophamide (4-HC), in vitro and confirmed the loss of primordial oocytes but no change in the number of primary and secondary follicles. We demonstrated that phospho-AKT (p-AKT) and cleaved PARP (cPARP) are present in primordial oocytes 3 days after CPA injection, consistent with the role of these markers as part of the apoptotic cascade. Interestingly, p-AKT positive primordial oocytes co-expressed cPARP. Treatment of animals with specific inhibitors of apoptotic pathway components, ETP46464 and CHK2, blocked 4-HC‒induced DNA damage in vitro. These data suggest that CPA targets primordial germ cells in the ovarian reserve by stimulating apoptosis pathways. Adjuvant therapies to protect primordial germ cells from the off-target effects of CPA may reduce the risk of POI.

Barriers to foot care in patients with diabetes as identified by healthcare professionals

AIMS

To seek the views of healthcare professionals as to the barriers to foot care that they perceive as having an impact on clinical outcomes and contributing to the number of amputations.

METHODS

The study involved healthcare professionals from the UK attending our 2015 and 2016 Masterclass diabetic foot conferences. Admission to these conferences was open to all members of the multidisciplinary spectrum who provide care of people with diabetes and foot problems. Attendees were asked to write down concerns that they considered to constitute barriers to foot care for people with diabetes.

RESULTS

A total of 425 responses were received (90.8% of the total attendance at the 2015/2016 conferences). Analysis of the responses produced eight key subject areas in which barriers to care were identified: patient referrals, communication between disciplines, access to specialist services, patient care, funding, organization of care, education and infection. Within these key areas, respondents reported poor recognition and diagnosis of foot problems, lack of awareness of the need for referral both by the person with diabetes and healthcare professionals, difficulties in the referral pathway, lack of access to multidisciplinary care, shortage of resources and lack of education of both people with diabetes and healthcare professionals. The respondents identified these barriers as contributing to delay in people with diabetes receiving specialist help. Such a delay can lead to amputation.

CONCLUSIONS

The crucial barrier to diabetic foot care is delay in accessing specialist care. Until this is addressed, care will be less than optimum and amputations will continue.

Reliability of a novel thermal imaging system for temperature assessment of healthy feet

Background

Thermal imaging is a useful modality for identifying preulcerative lesions (“hot spots”) in diabetic foot patients. Despite its recognised potential, at present, there is no readily available instrument for routine podiatric assessment of patients at risk. To address this need, a novel thermal imaging system was recently developed. This paper reports the reliability of this device for temperature assessment of healthy feet.

Methods

Plantar skin foot temperatures were measured with the novel thermal imaging device (Diabetic Foot Ulcer Prevention System (DFUPS), constructed by Photometrix Imaging Ltd) and also with a hand-held infrared spot thermometer (Thermofocus® 01500A3, Tecnimed, Italy) after 20 min of barefoot resting with legs supported and extended in 105 subjects (52 males and 53 females; age range 18 to 69 years) as part of a multicentre clinical trial. The temperature differences between the right and left foot at five regions of interest (ROIs), including 1st and 4th toes, 1st, 3rd and 5th metatarsal heads were calculated. The intra-instrument agreement (three repeated measures) and the inter-instrument agreement (hand-held thermometer and thermal imaging device) were quantified using intra-class correlation coefficients (ICCs) and the 95% confidence intervals (CI).

Results

Both devices showed almost perfect agreement in replication by instrument. The intra-instrument ICCs for the thermal imaging device at all five ROIs ranged from 0.95 to 0.97 and the intra-instrument ICCs for the hand-held-thermometer ranged from 0.94 to 0.97. There was substantial to perfect inter-instrument agreement between the hand-held thermometer and the thermal imaging device and the ICCs at all five ROIs ranged between 0.94 and 0.97.

Conclusions

This study reports the performance of a novel thermal imaging device in the assessment of foot temperatures in healthy volunteers in comparison with a hand-held infrared thermometer. The newly developed thermal imaging device showed very good agreement in repeated temperature assessments at defined ROIs as well as substantial to perfect agreement in temperature assessment with the hand-held infrared thermometer. In addition to the reported non-inferior performance in temperature assessment, the thermal imaging device holds the potential to provide an instantaneous thermal image of all sites of the feet (plantar, dorsal, lateral and medial views).

Trial registration

Diabetic Foot Ulcer Prevention System NCT02317835, registered December 10, 2014

Undiagnosed severe sleep apnoea and diabetic foot ulceration - a case series based hypothesis: a hitherto under emphasized factor in failure to heal

BACKGROUND

Although great progress has been made in managing diabetic foot disease, it continues to carry significant morbidity and mortality. Obstructive sleep apnoea (OSA) and diabetes frequently coexist and recent studies suggest significant under-recognition of OSA in those with diabetes. There are no current reports on the direct clinical impact of OSA on acute or chronic diabetic foot ulcer healing.

CASE REPORT

We describe three cases with Type 2 diabetes and a mean BMI of 50 kg/m(2) in whom we believe undiagnosed severe OSA may have impeded the rate of recovery of acutely infected foot ulcers. Despite standard care whilst in hospital with optimization of glycaemia, daily wound care, ulcer offloading techniques including casting, it was difficult to achieve satisfactory granulation in the first two cases with previously unrecognized and hence untreated severe OSA (Apnoea-Hypopnea Index > 30) until correction had been achieved through continuous positive airway pressure therapy (CPAP). In the third case, despite all optimization techniques, healing has not been achieved and individuals' reluctance to consider CPAP may be one possible factor.

DISCUSSION

We observe in three severely obese individuals with diabetes that untreated severe OSA may have contributed to delayed wound healing. We also observed an improvement in two individuals after institution of CPAP therapy. Clinicians managing the diabetic foot should consider investigating the presence of OSA in non-healing or slowly progressive foot ulcers when all other factors have been fully optimized.

Acute Charcot neuro-osteoarthropathy

Charcot neuro-osteoarthropathy (CN) is one of the most challenging foot complications in diabetes. Common predisposing and precipitating factors include neuropathy and increased mechanical forces, fracture and bone resorption, trauma and inflammation. In the last 15 years, considerable progress has been made in the early recognition of the acute Charcot foot when the X ray is still negative (stage 0 or incipient Charcot foot). Recent advances in imaging modalities have enabled the detection of initial signs of inflammation and underlying bone damage before overt bone and joint destruction has occurred. Casting therapy remains the mainstay of medical therapy of acute CN. If timely instituted, offloading can arrest disease activity and prevent foot deformity. In cases with severe deformity, modern surgical techniques can correct the unstable deformity for improved functional outcome and limb survival. Emerging new studies into the cellular mechanisms of severe bone destruction have furthered our understanding of the mechanisms of pathological bone and joint destruction in CN. It is hoped that these studies may provide a scientific basis for new interventions with biological agents.

Inflammatory and bone turnover markers in a cross-sectional and prospective study of acute Charcot osteoarthropathy

AIMS

To assess markers of inflammation and bone turnover at presentation and at resolution of Charcot osteoarthropathy.

METHODS

We measured serum inflammatory and bone turnover markers in a cross-sectional study of 35 people with Charcot osteoarthropathy, together with 34 people with diabetes and 12 people without diabetes. In addition, a prospective study of the subjects with Charcot osteoarthropathy was conducted until clinical resolution.

RESULTS

At presentation, C-reactive protein (P = 0.007), tumour necrosis factor-α (P = 0.010) and interleukin-6 (P = 0.002), but not interleukin-1β, (P = 0.254) were significantly higher in people with Charcot osteoarthropathy than in people with and without diabetes. Serum C-terminal telopeptide (P = 0.004), bone alkaline phosphatase (P = 0.006) and osteoprotegerin (P < 0.001), but not tartrate-resistant acid phosphatase (P = 0.126) and soluble receptor activator of nuclear factor-κβ ligand (P = 0.915), were significantly higher in people with Charcot osteoarthropathy than in people with and without diabetes. At follow-up it was found that tumour necrosis factor-α (P = 0.012) and interleukin-6 (P = 0.003), but not C-reactive protein (P = 0.101), interleukin-1β (P = 0.457), C-terminal telopeptide (P = 0.743), bone alkaline phosphatase (P = 0.193), tartrate-resistant acid phosphatase (P = 0.856), osteoprotegerin (P = 0.372) or soluble receptor activator of nuclear factor-kβ ligand (P = 0.889), had significantly decreased between presentation and the 3 months of casting therapy time point, and all analytes remained unchanged from 3 months of casting therapy until resolution. In people with Charcot osteoarthropathy, there was a positive correlation between interleukin-6 and C-terminal telopeptide (P = 0.028) and tumour necrosis factor-α and C-terminal telopeptide (P = 0.013) only at presentation.

CONCLUSIONS

At the onset of acute Charcot foot, serum concentrations of tumour necrosis factor-α and interleukin-6 were elevated; however, there was a significant reduction in these markers at resolution and these markers may be useful in the assessment of disease activity.

Medical management of Charcot arthropathy

Charcot arthropathy is a major complication of diabetes and it poses management challenges to health care professionals. Early diagnosis and timely intervention are essential for improved outlook of these patients. Casting therapy has been accepted as the mainstay treatment of the acute Charcot foot, although there are still controversies regarding its duration, the choice of removable and non-removable device and weight-bearing casts vs. non-weight-bearing casts. Two groups of antiresorptive therapies have been evaluated in the treatment of the acute Charcot foot, bisphosphonates (intravenous and oral) and calcitonin. These therapies have clearly shown a reduction of bone turnover, although, they have not shown a significant effect on temperature reduction. Current evidence to support their use is weak. An anabolic agent to speed up clinical resolution and fracture healing may be helpful and a clinical trial to evaluate the possible benefit of 1-84 recombinant human parathyroid hormone on fracture healing in the acute Charcot foot is in progress. This paper summarises the current approach to medical management of acute Charcot arthropathy with specific emphasis on casting and pharmacological therapy. Emerging new studies of the pathogenesis of this condition are also discussed.

Maple polyphenols, ginnalins A-C, induce S- and G2/M-cell cycle arrest in colon and breast cancer cells mediated by decreasing cyclins A and D1 levels

Polyphenols are bioactive compounds found in plant foods. Ginnalins A-C are polyphenols present in the sap and other parts of the sugar and red maple species which are used to produce maple syrup. Here we evaluated the antiproliferative effects of ginnalins A-C on colon (HCT-116) and breast (MCF-7) tumourigenic and non-tumourigenic colon (CCD-18Co) cells and investigated whether these effects were mediated through cell cycle arrest and/or apoptosis. Ginnalins A-C were twofold more effective against the tumourigenic than non-tumourigenic cells. Among the polyphenols, ginnalin A (84%, HCT-116; 49%, MCF-7) was more effective than ginnalins B and C (50%, HCT-116; 30%, MCF-7) at 50 μM concentrations. Ginnalin A did not induce apoptosis of the cancer cells but arrested cell cycle (in the S- and G(2)/M-phases) and decreased cyclins A and D1 protein levels. These results suggest that maple polyphenols may have potential cancer chemopreventive effects mediated through cell cycle arrest.

Five-year follow-up of a cohort of people with their first diabetic foot ulcer: the persistent effect of depression on mortality

AIMS/HYPOTHESIS

Depressive disorders are associated with mortality within 18 months of presentation of diabetic foot ulcers (DFU). The main aim of this study was to determine whether depressive disorder is still associated with increased mortality in people with their first foot ulcer at 5 years.

METHODS

This is a 5-year follow-up of a cohort of 253 patients presenting with their first DFU. At baseline, the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) 2.1 was used to define those who met DSM-IV (Diagnostic and Statistical Manual 4th edition) criteria for depressive disorder. Cox regression analysis controlled for potential covariates: age, sex, marital status, socioeconomic status, smoking, mean HbA(1c), diabetes complications and ulcer severity. The main outcome was mortality at 5 years.

RESULTS

The prevalence of DSM-IV depressive disorder at baseline was 32.2% (n = 82). There were 92 (36.4%) deaths over the 5 years of follow-up. In the Cox regression (n = 246), after adjusting for covariates, baseline DSM-IV depressive disorder was significantly associated with a twofold increased risk of mortality for any depressive episode (HR 2.09, 95% CI 1.34, 3.25), minor (HR 1.93, 95% CI 1.00, 3.74) or major depressive disorders (HR 2.18, 95% CI 1.31, 3.65), compared with patients who were not depressed.

CONCLUSIONS/INTERPRETATION

Depression is associated with a persistent twofold increased risk of mortality in people with their first DFU at 5 years.

New galloyl derivative from winged sumac (Rhus copallinum) fruit

Twelve compounds were isolated from Winged Sumac (Rhus copallinum) fruit and their structures were elucidated on the basis of NMR and mass spectral data. The isolates included a new galloyl derivative, (R)-galloyl malic acid dimethyl ester (1), and eleven known compounds, gallic acid (2), methyl gallate (3), glucogallin (4), methyl m-digallate (5), methyl p-digallate (6), quercetin (7), myricetin (8), rhamnazin (9), kaempferol (10), betulinic acid (11), and oleanolic acid (12). All of the compounds were evaluated for antiproliferative effects against human colon tumorigenic (HCT-116, Caco-2) and nontumorigenic (CCD18-Co) cell lines.

New Galloyl Derivative from Winged Sumac (Rhus copallinum) Fruit

Twelve compounds were isolated from Winged Sumac ( Rhus copallinum) fruit and their structures were elucidated on the basis of NMR and mass spectral data. The isolates included a new galloyl derivative, (R)-galloyl malic acid dimethyl ester (1), and eleven known compounds, gallic acid (2), methyl gallate (3), glucogallin (4), methyl m-digallate (5), methyl p-digallate (6), quercetin (7), myricetin (8), rhamnazin (9), kaempferol (10), betulinic acid (11), and oleanolic acid (12). All of the compounds were evaluated for antiproliferative effects against human colon tumorigenic (HCT-116, Caco-2) and non-tumorigenic (CCD18-Co) cell lines.

Audit of acute Charcot's disease in the UK: the CDUK study

AIMS/HYPOTHESIS

We studied factors associated with the development and resolution of acute Charcot foot using a web-based observational study.

METHODS

Clinicians managing cases of acute Charcot foot in the UK and Ireland between June 2005 and February 2007 were invited to register anonymised details on a secure website.

RESULTS

A total of 288 cases (age 57.0 ± 11.3 years [mean ± SD]; 71.2% male) were registered from 76 centres. Of these, 36% of patients recalled an episode of relevant trauma in the preceding 6 months, while 12% had had surgery to the affected foot. In 101 (35%) cases, ulceration was present at registration and 20% of these had osteomyelitis. Non-removable off-loading devices were used at presentation in 35.4% of cases, with removable off-loading used in 50%. Data on resolution were available for 219 patients. The median time to resolution was 9 months in patients whose initial management included the use of non-removable off-loading, compared with 12 months in the remainder (p = 0.001). Bisphosphonates were administered intravenously in 25.4% and orally in 19.4% of cases. The median time to resolution in patients who received bisphosphonates was 12 months and was longer than in those who did not (10 months, p = 0.005).

CONCLUSIONS/INTERPRETATION

The median time to resolution was longer than in earlier series. Although limited by being observational and non-randomised, these data suggest that the use of non-removable off-loading at presentation may shorten the time to resolution. They provide no evidence to indicate that the use of bisphosphonates is beneficial.

Thiazolidinediones induce osteocyte apoptosis and increase sclerostin expression

AIMS

Thiazolidinediones (TZDs) are associated with a higher risk of bone fracture in women compared with men. The aim of the present study was to investigate whether TZDs could influence osteocyte behaviour and contribute to the skeletal phenotype observed in TZD-treated patients.

METHODS

The murine MLO-Y4 cell line was used as a source of osteocytes. These cells were cultured for 24 h with 0, 10(-8) m, 10(-7) m, 10(-6) m, 10(-5) m or 10(-4) m of pioglitazone, rosiglitazone or troglitazone in the presence or absence of 17beta-oestradiol. The extent of osteocyte apoptosis was assessed, as was the expression of the bone formation inhibitor sclerostin and receptor activator for nuclear factor kappaB ligand (RANKL) also.

RESULTS

In the absence of 17beta-oestradiol, pioglitazone, rosiglitazone and troglitazone induced osteocyte apoptosis dose-dependently even at the lowest concentration of 10(-8) m. Furthermore, the expression of sclerostin but not RANKL was significantly increased in TZD-treated cultures compared with untreated cultures. The presence of 17beta-oestradiol significantly reduced TZD-induced osteocyte apoptosis and also sclerostin up-regulation.

CONCLUSIONS

These findings therefore raise the potential concern of using TZDs in post-menopausal women where the lack of oestrogen would not prevent osteocyte apoptosis and sclerostin up-regulation and may aggravate the reduction in bone mass in these patients.

Role of neuropathy on fracture healing in Charcot neuro-osteoarthropathy

Charcot neuro-osteoarthropathy (CNO) is a devastating condition affecting most commonly the foot/ankle joint in diabetic patients and may lead to severe deformities and amputation. Peripheral sensory neuropathy seems to be a pre-requisite to the development of CNO. The aim of this review article is to summarise the skeletal effects of the nervous system on bone remodelling and fracture healing of normal and damaged joints and to describe how neuropathy, in the context of modern concept of neuro-osteopathology, is crucial in the predisposition of the patient to develop acute CNO.

Day-case angioplasty in diabetic patients with critical ischemia

AIM

Recent studies have shown that percutaneous transluminal angioplasty (PTA) can be safely performed as a day-case procedure. Many centers consider diabetes mellitus as a contraindication to day-case PTA. In this study, the safety and efficacy of 95 day-case PTA in 66 diabetic patients with critical leg ischemia (CLI) were evaluated.

METHODS

Diabetic patients with CLI were assessed in a one-stop multidisciplinary outpatient clinic. Sixty-six outpatients with CLI deemed suitable for radiological intervention by non-invasive imaging (ultrasound angiology or magnetic resonance angiography) were scheduled for day-case PTA.

RESULTS

PTA was initially successful in 63 out of 66 patients (95%). In 3 patients (5%), PTA was not possible because the lesion could not be balloon dilated or crossed with a guide wire. Clinically suspected first, second and third re-stenosis confirmed by non-invasive studies occurred in 20 out of 63 (31%), 7 out of 20 (35%) and 2 out of 7 (28%) patients, respectively. Following PTA, debridement was performed in 11 patients (17%), minor amputation in 8 (13%) and major amputation in 3 (5%). Relief of the primary symptom of rest pain or healing of ulcers was achieved in 23 out of 32 (72%) and 25 out of 27 (92.5%) patients, respectively. No peri-interventional morbidity or mortality was encountered.

CONCLUSION

PTA is feasible and safe as a day-case procedure in diabetic patients with CLI. Re-stenosis can be managed by repeat day-case PTA.

Charcot neuro-osteoarthropathy-current standards

It is extremely important to have a high index of suspicion for Charcot neuro-osteoarthropathy (CN) and to encourage early presentation of the patient. This should be followed by a rapid diagnosis and early intervention, and with such a modern approach many CN can now be healed and deformity prevented. CN can be divided into two phases: acute active phase and chronic stable phase. The acute active phase includes those patients presenting early with normal X-ray and those presenting later with deformity and radiological changes of CN. The acute phase is characterized by unilateral erythema and oedema. The foot is at least 2 degrees C hotter than the contralateral foot. Patients should have initially an X-ray examination which, at this time, may be normal. We then proceed to two investigations: initially a technetium diphosphonate bone scan, which will detect early evidence of bone damage and also locate the site of this damage. If the result of the bone scan is positive, we would proceed to magnetic resonance imaging (MRI) examination, which would describe in more detail the nature of the bony damage. The aim of treatment is immobilization in a plaster cast until there is no longer evidence on X-ray of continuing bone destruction, and the foot temperature is within 2 degrees C of the contralateral foot. An alternative treatment is a prefabricated walking cast, such as the Aircast. A randomized controlled study of a single 90 mg pamidronate infusion has shown a significant reduction of the markers of bone turnover and skin temperature in treated, compared with control subjects although the fall in skin temperature was similar in both groups. There was a similar finding in a recent study with alendronate. Calcitonin has also been used in the acute stage and there was a more rapid transition to the stable chronic phase in the treated group compared with controls. In the chronic stable phase, the foot is no longer warm and red. There may still be oedema but the difference in skin temperature between the feet is usually less than 2 degrees C. The X-ray shows fracture healing, sclerosis and bone remodelling. The patient must now be rehabilitated and gradually moved from cast treatment to suitable footwear. The patient needs close observation to detect any relapse, which will be evident from further swelling and heat in the foot. Careful rehabilitation is always necessary after a long period in a cast.

Calcaneal bone mineral density in patients with Charcot neuropathic osteoarthropathy: differences between Type 1 and Type 2 diabetes

AIMS

To measure bone density and neuropathy in both feet in Type 1 and Type 2 patients with unilateral Charcot osteoarthropathy and controls.

METHODS

Calcaneal bone density, temperature and vibration thresholds were compared between 17 Type 1 diabetic patients with osteoarthropathy and 47 Type 1 controls and between 18 Type 2 diabetic patients and 48 Type 2 controls. As well as the Charcot foot, the non-Charcot foot was studied to assess osteopenia at onset of osteoarthropathy.

RESULTS

In Type 1 diabetes, bone density was reduced in the non-Charcot foot compared with controls [Z-score: -1.7 ({-1.9}-{-1.4}) vs. -0.2 ({-1.1}-{0.5}), P < 0.0001, median (interquartile range)]; but not in Type 2 diabetes [Z-score: 0.15 ({-0.45}-{0.85}) vs. 0.3 ({-0.5}-{0.9}), P = 0.675]. Bone density in the Charcot foot was lower compared with the non-Charcot foot in both Type 1 [Z-score: -2.0 ({-2.8}-{-1.4}) vs. -1.7 ({-1.9}-{-1.4}), P = 0.018] and Type 2 diabetes [Z-score: -0.2 ({-1.4}-{0.1}) vs. 0.3 ({-0.5}-{0.9}), P = 0.001]. In Type 1 diabetes, bone density of the non-Charcot foot was reduced compared with that in Type 2 (P < 0.0001). Body mass index was lower in Type 1 than in Type 2 Charcot patients (P = 0.007). Type 2 patients had high temperature (P = 0.001) and vibration thresholds (P < 0.0001) in the non-Charcot foot compared with Type 2 controls whereas Type 1 patients had a high temperature threshold (P = 0.01) but not vibration threshold compared with Type 1 controls (P = 0.077).

CONCLUSION

Bone density was reduced in the non-Charcot foot in Type 1 but not in Type 2 diabetes. Type 2 patients had high temperature and vibration thresholds in contrast to Type 1 patients who had a high temperature threshold only.

Safety and performance of a new non-adhesive foam dressing for the treatment of diabetic foot ulcers

OBJECTIVE

This study aimed to document the safety and performance of a new non-adhesive foam dressing (Biatain Non-adhesive Dressing, Coloplast A/S) in the treatment of established foot ulcers in patients with diabetes.

METHOD

This was an open non-comparative prospective study. Participants had an ankle brachial pressure index score of over 0.4 (neuro-ischaemic) and an ulcer bigger than 1 cm2 and less than 8 cm2 in any direction. The treatment period was six weeks.

RESULTS

Thirty-five out of 37 patients completed the study. The mean wound area reduced from 5.4 cm2 to 2.5 cm2. Relative wound area reduced from 100% at baseline to 40% at week 6. 'Wearing comfort' improved throughout the study (p = 0.039). Maceration remained stable or improved. None of the four reported adverse events were device related.

CONCLUSION

This study demonstrates that treatment of diabetic foot ulcers with Biatain Non-adhesive Dressing results in considerable wound area reduction and prevents any deterioration in maceration. The dressing is safe and effective in the management of these ulcers.

Is neuropathic ulceration the key to understanding increased mortality due to ischaemic heart disease in diabetic foot ulcer patients? A population approach using a proportionate model

Ischaemic heart disease (IHD) is the commonest cause of death in diabetic foot ulcer patients and non-ulcerated diabetic patients, yet the mortality rate of diabetic foot ulcer patients is over twice that of non-ulcerated patients. As the cause of this increased mortality is not understood, we plotted the ratio of deaths due to ischaemic heart disease (IHDn) to other causes of death (i.e. IHDn:OCDn) against age for 242 diabetic foot ulcer patients and 121 controls (non-ulcerated diabetic patients). The IHDn:OCDn ratio rose above 1.0 from age 40 years onwards for diabetic foot ulcer patients, but from age 70 years onwards for controls, demonstrating differentially increased mortalities due to IHD. A population model involving summation of IHDn:OCDn ratios for neuropathic and neuroischaemic diabetic foot ulcer patients calculated an overall increased mortality rate of 1.8 compared with that of non-ulcerated diabetics. The model predicted that a 25% reduction in neuropathic diabetic foot ulcer patients dying from IHD would eliminate the increased mortality, demonstrating that neuropathic rather than ischaemic ulceration defines the cause of increased mortality among diabetic foot ulcer patients.

Bisphosphonates in the treatment of Charcot neuroarthropathy: a double-blind randomised controlled trial

AIMS/HYPOTHESIS

The management of charcot neuroarthropathy, a severe disabling condition in diabetic patients with peripheral neuropathy, is currently inadequate with no specific pharmacological treatment available. We undertook a double-blind randomised controlled trial to study the effect of pamidronate, a bisphosphonate, in the management of acute diabetic Charcot neuroarthropathy.

METHODS

Altogether 39 diabetic patients with active Charcot neuroarthropathy from four centres in England were randomised in a double-blind placebo-controlled trial. Patients received a single infusion of 90 mg of pamidronate or placebo (saline). Foot temperatures, symptoms and markers of bone turnover (bone specific alkaline phosphatase and deoxypyridinoline crosslinks) were measured over the 12 months, in 10 visits. All patients also had standard treatment of the Charcot foot.

RESULTS

Mean age of the study group (59 % Type II (non-insulin-dependent) diabetes mellitus) was 56.3 +/- 10.2 years. The mean temperature difference between active and control groups was 3.6 +/- 1.7 degrees C and 3.3 +/- 1.4 degrees C, respectively. There was a fall in temperature of the affected foot in both groups after 2 weeks with a further reduction in temperature in the active group at 4 weeks (active and placebo vs baseline; p = 0.001; p = 0.01, respectively), but no difference was seen between groups. An improvement in symptoms was seen in the active group compared with the placebo group (p < 0.001). Reduction in bone turnover (means +/- SEM) was greater in the active than in the control group. Urinary deoxypyridinoline in the pamidronate treated group fell to 4.4 +/- 0.4 nmol/mmol creatinine at 4 weeks compared with 7.1 +/- 1.0 in the placebo group (p = 0.01) and bone-specific alkaline phosphatase fell to 14.1 +/- 1.2 u/l compared with 18.6 +/- 1.6 u/l after 4 weeks, respectively (p = 0.03).

CONCLUSION/INTERPRETATION

The bisphosphonate, pamidronate, given as a single dose leads to a reduction in bone turnover, symptoms and disease activity in diabetic patients with active Charcot neuroarthropathy.

Infection of foot ulcers with Staphylococcus aureus associated with increased mortality in diabetic patients

Diabetic patients with foot ulceration have a poorer prognosis than those without ulceration. The reason for this is unclear, but there is considerable interest in the putative links between infection and atherogenesis, and it is notable that diabetic foot ulcers (DFU) are often infected with Staphylococcus aureus and the main cause of death in DFU patients is ischaemic heart disease. We examined the 5 year survival of 71 diabetic patients who presented with foot ulcers that were newly infected (Sa group, n = 56) or not infected at all during the study period (non-Sa group, n = 15) with S. aureus. Twenty-nine patients (52%) infected with S. aureus died compared with three patients (20%) whose foot ulcers were not infected with S. aureus. The patients in the two groups were similar in age and duration of diabetes. The overall five year mortality rate was 10.4% per year for those infected, significantly higher than the average of 4.0% for patients without infection (p = 0.015). None of the patients was bacteraemic or died directly from sepsis. Infection of DFU by S. aureus may increase the risk of death in diabetic patients.

Medial arterial calcification and diabetes mellitus

Medial arterial calcification (MAC) is a frequent vascular finding in patients with type II diabetes mellitus. Morphologically distinct from focal calcifications of atherosclerosis its radiographically distinct tramline pattern is frequently encountered in the arteries of the lower extremities. MAC is inconsistently related to age, duration and therapy of diabetes. In contrast, a strong association with diabetic polyneuropathy and familial aggregation have been documented. Although initially considered benign MAC is now recognized as a strong predictor of cardiovascular morbidity and mortality in diabetic patients. Investigations into MAC pathogenes and into its role in vascular pathophysiology are underway.

Plantar pressures are elevated in the neuroischemic and the neuropathic diabetic foot

OBJECTIVE

Clinical observation has noted that diabetic neuropathic ulcers occur frequently on the plantar surface, whereas neuroischemic ulcers seem to occur often on the foot margins. The reason for this difference in the site of ulceration is unknown, but it may be related to differences in pressure loading. The aim of the study was to compare vertical in-shoe foot pressures measured during walking (using the F-SCAN system) in four groups of patients whose degree of neuropathy was measured by vibration perception threshold (VPT).

RESEARCH DESIGN AND METHODS

Subjects included 14 neuroischemic diabetic patients (VPT 29.3 +/- 13.5 V) with history of ulceration on the margins of the foot, 18 patients with neuropathy alone (VPT 38.7 +/- 12.7 V) and previous history of ulceration on the plantar surface, 10 diabetic control patients (VPT 9.9 +/- 2.7 V), and 15 nondiabetic control subjects (VPT 7.0 +/- 0.5 V).

RESULTS

When compared with the other three groups, neuroischemic patients had higher foot pressures when measured as mean peak pressures and highest peak pressures under four areas of the foot: medial and lateral forefoot, hallux, and heel. Furthermore, when measuring the maximum pressures developed at any point under the plantar surface, the neuroischemic patients also had the most elevated pressures (757.6 +/- 135.9 kPa), significantly higher than those found in the neuropathic group (482.8 +/- 68.6 kPa, P = 0.04) and in both diabetic control patients (310.2 +/- 34.7 kPa, P = 0.008) and nondiabetic controls subjects (365.1 +/- 49.8 kPa, P = 0.007).

CONCLUSIONS

Despite having increased plantar pressures and a comparable degree of neuropatny, the neuroischemic patients did not have a history of ulceration on the plantar surface. These observations may have relevance to different mechanisms of ulcer formation in the neuroischemic and neuropathic foot.

Medial localization of mineralization-regulating proteins in association with Mönckeberg's sclerosis: evidence for smooth muscle cell-mediated vascular calcification

BACKGROUND

Calcification of the media of peripheral arteries is referred to as Mönckeberg's sclerosis (MS) and occurs commonly in aged and diabetic individuals. Its pathogenesis is unknown, but its presence predicts risk of cardiovascular events and leg amputation in diabetic patients. Several studies have documented expression of bone-associated genes in association with intimal atherosclerotic calcification, leading to the suggestion that vascular calcification may be a regulated process with similarities to developmental osteogenesis. Therefore, we examined gene expression in vessels with MS to determine whether there was evidence for a regulated calcification process in the vessel media.

METHODS AND RESULTS

In situ hybridization, immunohistochemistry, and semiquantitative reverse-transcription polymerase chain reaction were used to examine the expression of mineralization-regulating proteins in human peripheral arteries with and without MS. MS occurred in direct apposition to medial vascular smooth muscle cells (VSMCs) in the absence of macrophages or lipid. These VSMCs expressed the smooth muscle-specific gene SM22alpha and high levels of matrix Gla protein but little osteopontin mRNA. Compared with normal vessels, vessels with MS globally expressed lower levels of matrix Gla protein and osteonectin, whereas alkaline phosphatase, bone sialoprotein, bone Gla protein, and collagen II, all indicators of osteogenesis/chondrogenesis, were upregulated. Furthermore, VSMCs derived from MS lesions exhibited osteoblastic properties and mineralized in vitro.

CONCLUSIONS

These data indicate that medial calcification in MS lesions is an active process potentially orchestrated by phenotypically modified VSMCs.

Novel surgical treatment and gastric pathology in diabetic gastroparesis

AIMS

Observations are made on four Type 1 diabetic patients with the rare syndrome of intractable vomiting from confirmed gastroparesis, to determine whether radical surgery would alleviate their symptoms and subsequently to examine in detail the gastric histopathology.

METHODS

The surgical approach consisted of an approximate 70% resection of the stomach, including the antrum and pylorus, with closure of the duodenum and restoration of gastrointestinal continuity with a 60-cm Roux-en-Y jejunal loop. Four longstanding Type 1 diabetic patients were examined and treated as described. They were all women in the age range 2741 years with grossly abnormal autonomic function tests in whom other causes for gastric paresis had been excluded.

RESULTS

Vomiting episodes leading to multiple hospital admissions (6-8) in the year preceding surgery were eliminated in three of the four patients, while in the fourth initial success was followed by the need for dialysis for renal failure. Gastric histopathology showed evidence of smooth muscle degeneration and fibrosis, with eosinophilic inclusion bodies (M-bodies) which appear to be unique to this condition. The findings suggest the presence of a gastromyopathy.

CONCLUSIONS

Satisfactory relief of intractable vomiting from diabetic gastroparesis was achieved by a novel radical surgical procedure. Histopathological findings suggest that gastromyopathy may contribute to the production of this syndrome.

Why do foot ulcers recur in diabetic patients?

AIM

To investigate factors predisposing to recurrent foot ulceration in patients with diabetes mellitus.

METHODS

Two groups of patients who had attended a specialist Diabetes Foot Centre were assessed: relapsers (n = 26), whose foot ulceration had recurred at least twice, and nonrelapsers (n = 25), whose initial ulcer had not recurred for at least 2 years.

RESULTS

In the relapser group 10/26 patients waited at least 24 h before reporting symptoms compared with only 2/25 in the nonrelapser group (P < 0.05). Vibration perception threshold (volts) was 38 +/- 12 (mean +/- SD) in relapsers compared with 25 +/- 13 in nonrelapsers (P < 0.005). Cold perception threshold (degrees C) was 9.1 +/- 4.6 in relapsers compared with 5.1 +/- 3.5 in nonrelapsers (P<0.005). HbA1c (%) was significantly raised at 8.5 +/- 1.7 in relapsers compared with 7.6 +/- 1.2 in nonrelapsers (P = 0.03). Alcohol intake was 0.5 (median, interquartile range 0-2) units per day in relapsers compared with 0.0 (median, interquartile range 0-0.25) units in nonrelapsers (P = 0.04). Smoking habits, housing conditions, visual acuity, threshold for warm perception and the Doppler pressure index were not significantly different in the two groups.

CONCLUSIONS

Patients who develop recurrent foot ulceration delay in reporting symptoms, when compared with diabetic patients whose foot ulceration does not recur. The relapsers also have evidence of poorer glycaemic control, more neuropathy and increased alcohol intake.

Randomised placebo-controlled trial of granulocyte-colony stimulating factor in diabetic foot infection

BACKGROUND

Diabetic foot infections cause substantial morbidity and mortality. Neutrophil superoxide generation, a crucial part of neutrophil bactericidal activity, is impaired in diabetes. Granulocyte-colony stimulating factor (G-CSF) increases the release of neutrophils from the bone marrow and improves neutrophil function. We assessed G-CSF as adjuvant therapy for the treatment of severe foot infections in diabetic patients.

METHODS

40 diabetic patients with foot infections were enrolled in a double-blind placebo-controlled study. On admission, patients were randomly assigned G-CSF (filgrastim) therapy (n = 20) or placebo (n = 20) for 7 days. Both groups received similar antibiotic and insulin treatment. Neutrophils from the peripheral blood of these participants and from healthy controls were stimulated with opsonised zymosan, and superoxide production was measured by a spectrophotometric assay (reduction of ferricytochrome C).

FINDINGS

G-CSF therapy was associated with earlier eradication of pathogens from the infected ulcer (median 4 [range 2-10] vs 8 [2-79] days in the placebo group; p = 0.02), quicker resolution of cellulitis (7 [5-20] vs 12 [5-93] days; p = 0.03), shorter hospital stay (10 [7-31] vs 17.5 [9-100] days; p = 0.02), and a shorter duration of intravenous antibiotic treatment (8.5 [5-30] vs 14.5 [8-63] days; p = 0.02). No G-CSF-treated patient needed surgery, whereas two placebo recipients underwent to amputation and two had extensive debridement under anaesthesia. After 7 days' treatment, neutrophil superoxide production was significantly higher in the G-CSF group than in the placebo group (16.1 [4.2-24.2] vs 7.3 [2.1-11.5] nmol per 10(6) neutrophils in 30 min; p < 0.0001). G-CSF therapy was generally well tolerated.

INTERPRETATION

G-CSF treatment was associated with improved clinical outcome of foot infection in diabetic patients. This improvement may be related to an increase in neutrophil superoxide production.

Measurement of markers of osteoclast and osteoblast activity in patients with acute and chronic diabetic Charcot neuroarthropathy

Excess osteoclast activity is believed to be responsible for the early bone changes associated with Charcot neuroarthropathy in diabetes mellitus. Markers of osteoclast and osteoblast activity were measured in four groups of patients: 16 with an acute Charcot foot, 16 with a chronic Charcot foot, 10 diabetic controls, and 10 non-diabetic controls. Serum carboxyterminal telopeptide of type 1 collagen (1CTP), a marker of osteoclastic bone resorption, was significantly raised in the dorsal venous arch of the acute Charcot foot, 6.1 +/- 1.5 microg l(-1) (mean +/- SD) compared with the chronic Charcot foot 4.1 +/- 1.4, diabetic controls 3.3 +/- 1.4, and non-diabetic controls 2.8 +/- 1.4, p < 0.0001. This local increase in 1CTP was also reflected systemically in a study subgroup of 6 patients with acute Charcot neuroarthropathy, in whom peripheral antecubital vein 1CTP was 9.2 +/- 2.6 compared with 9.0 +/- 3.1 in the foot. In 6 chronic Charcot neuroarthropathy patients, foot (3.8 +/- 1.3) and systemic (4.0 +/- 1.5) 1CTP values were similar. Serum procollagen carboxyterminal propeptide (P1CP), an indicator of osteoblastic bone formation, was not significantly different between the feet of patients with acute Charcot neuroarthropathy 112 +/- 1.5 microg l(-1), patients with chronic Charcot neuroarthropathy 109 +/- 1.5 microg l(-1), diabetic controls 93.5 +/- 2.3 microg l(-1), and non-diabetic controls 90.1 +/- 1.5 microg l(-1). These results suggest that the acute Charcot foot demonstrates excess osteoclastic activity without concomitant increase in osteoblastic function. This may be important in its pathogenesis.

NO-dependent smooth muscle vasodilatation is reduced in NIDDM patients with peripheral sensory neuropathy

In order to determine the involvement of denervation in endothelium-independent, nitric oxide (NO)-dependent smooth muscle vasodilation, we have measured vascular endothelial and smooth muscle function in three groups of age- and sex-matched patients: 8 patients with non-insulin-dependent (Type 2) diabetes mellitus (NIDDM) with neuropathy; 7 NIDDM patients without neuropathy; and 10 non-diabetic control subjects. Laser Doppler probes were used to measure blood flow in the dorsum of the left foot. Vascular endothelial response was assessed by measuring vasodilatory responses to iontophoretic application of acetylcholine to the dorsum of the foot. Vascular smooth muscle activity was assessed by the response to iontophoresis of sodium nitroprusside (SNP)-a NO donor and direct vasodilator. The vasodilator response to acetylcholine, expressed as the ratio of peak to basal blood flow, was significantly reduced in both diabetic groups when compared to non-diabetic controls (geometric mean x/divided by anti-logged SD 9.81 x/divided by 1.65 versus patients with neuropathy 3.50 x/divided by 2.03, p < 0.005 and diabetic non-neuropathic subjects 3.49 x/divided by 1.67, p < 0.005). The difference between the two groups of diabetic patients was not significant. In contrast, the vasodilatation to nitroprusside was significantly reduced only in the diabetic neuropathic patients, significantly lower than in either the non-neuropathic diabetic controls or the non-diabetic controls (2.1 x/divided by 2.0 versus 6.42 x/divided by 1.56 and 7.02 x/divided by 2.05, p < 0.005). This indicates that neuropathy is important in abnormalities of endothelium-independent vasodilatation.

Pathology of the Diabetic Foot

The diabetic foot can be divided into two entities - the neuropathic foot and the neuro-ischaemic foot. It is essential to differentiate between the two, because each has characteristic complications including different types of ulcer, which require distinct therapeutic strategies.

Time-dependent behaviour of a force-sensitive resistor plantar pressure measurement insole

Thin pressure-measuring insoles have enabled new clinical studies of in-shoe distribution of plantar pressure. One of these new devices, based on force-sensitive resistor (FSR) technology, exhibits time-varying behaviour due to the mechanical properties of the sensor materials. This has been variously attributed to initial bedding in, wear or time-dependency behaviour. Cyclic and sustained loading were used in laboratory conditions to investigate this phenomenon. The results show that the sensitivity of the sensor varies rapidly over the first minute of loading. There is also a slower long-term effect which reduces over time. From this information, procedures for optimal calibration and use are suggested.

Reduction of gangrene and amputations in diabetic renal transplant patients: the role of a special foot clinic

This 4-year prospective study investigated the reasons for high levels of gangrene and major amputation in diabetic renal transplant patients and whether regular multidisciplinary foot care could reduce morbidity. All foot lesions were documented and investigated in 50 diabetic patients, mean age 49.2 +/- 11.0 (SD) years, duration of diabetes 25.3 +/- 9.0 years, time since renal transplantation 60.2 +/- 35.1 months, who attended a special foot clinic monthly for education, vascular and neurological assessment, podiatry and footwear. Foot lesions included: neuropathic ulcers, ischaemic ulcers, traumatic lesions, Charcot's arthropathy, pathological fracture. Treatment included antibiotics, podiatry, footwear, and angioplasty or distal bypass where appropriate. Only 13 patients were deemed ischaemic but peripheral neuropathy was a very common finding (mean VPT 24.8 +/- 12.9 V). Gangrene and major amputations showed a decrease on previous years and healing times for lesions were similar to those previously reported in diabetic patients without renal transplants. The majority of foot lesions, both in soft tissue and bone, were related to neuropathy and trauma and responded well to optimal foot care within the renal unit. Gangrene and major amputations were usually preventable.

The splanchnic circulation and postural hypotension in diabetic autonomic neuropathy

Postural hypotension results from sympathetic failure to cause superior peripheral vasoconstriction. The importance of the splanchnic circulation was studied by measuring mesenteric artery blood flow with duplex Doppler scanning. Nine normal and 9 Type 1 diabetic controls were compared to 8 Type 1 patients with autonomic neuropathy whose pressure fell 40-113 mmHg (range) on tilting. Measurements were made supine and after vertical tilt, fasting without insulin and after a 550 kcal meal. Superior mesenteric artery diameter decreased on tilting in normal controls but not in diabetic control or neuropathy groups (supine vs tilted: controls. 6.3 +/- 0.9 to 5 +/- 0.9 mm, p = 0.004, diabetic controls: 6.0 +/- 0.6 to 6.0 +/- 1.0 mm, and neuropathy group: 6.4 +/- 0.9 to 5.6 +/- 0.9 mm), but proportional blood flow changes were similar in all subjects (controls: 407 +/- 154 to 255 +/- 67 ml min-1 (-31%, p = 0.03), diabetic controls: 379 +/- 140 to 306 +/- 149 ml min-1 (-8%, p = 0.28), neuropathy group: 639 +/- 371 to 435 +/- 142 ml min-1 (-23%, p = 0.10). Postprandially supine superior mesenteric artery flow increased in all subjects but this did not affect the degree of systolic blood pressure drop on tilting (fasting vs postprandial blood flow: controls: 407 +/- 154 to 775 +/- 400 ml min-1 (p = 0.04), diabetic controls: 379 +/- 140 to 691 +/- 262 ml min-1 (p = 0.01), neuropathy group: 639 +/- 371 to 943 +/- 468 ml min-1 (p < 0.06)). The similarity of superior mesenteric artery responses to tilting in the three groups, and the lack of exacerbation of postural hypotension in the presence of postprandial hyperaemia indicates that control of splanchnic blood flow is less important in the aetiology of diabetic autonomic postural hypotension than previously thought.

Lower limb venous pressure in diabetic neuropathy

OBJECTIVE

Distended turgid veins have been noted in the feet of patients with diabetic neuropathy. This study assessed the supine venous pressure and its correlation with diabetic neuropathy and arteriovenous (AV) shunting in the feet of type I and type II diabetic subjects.

RESEARCH DESIGN AND METHODS

Seventeen patients with chronic Charcot joints, 11 patients with a history of neuropathic foot ulceration, 14 diabetic control subjects, and 11 normal control subjects were studied. Neuropathy was assessed by vibration and thermal thresholds and standard cardiovascular autonomic neuropathy tests. Supine venous pressure was measured by insertion of a 21-gauge needle connected to a strain gauge manometer into the veins on the dorsum of the foot. Venous PO2 was used as a measure of AV shunting.

RESULTS

Venous pressure was raised in the group with chronic Charcot joints (18.9 +/- 4.2 mmHg, P < 0.001 vs. the diabetic control group [11.3 +/- 2.6 mmHg]), the normal control group (12.3 +/- 2.3 mmHg, mean +/- SD), and the diabetic group with a history of neuropathic foot ulceration (16.0 +/- 3.7 mmHg, P = 0.008 vs. diabetic control subjects and P = 0.04 vs. normal control subjects), with a maximum of 28 mmHg. Venous pressure was correlated with heart rate variation to deep breathing, r = -0.61 (P = 0.001), vibration threshold, r = 0.56 (P = 0.001), Valsalva ratio, r = -0.64 (P -= 0.001), warm threshold, r = 0.69 (P = 0.001), and venous PO2, r = 0.43 (P = 0.02). There was no correlation with skin temperature, duration of diabetes, age, HbA1c, random blood glucose, ankle/brachial Doppler index, height, or serum creatinine.

CONCLUSIONS

Venous pressure is much higher in the neuropathic diabetic limb and is correlated with the severity of neuropathy and with AV shunting.

The value of the Neurometer in assessing diabetic neuropathy by measurement of the current perception threshold

The Neurometer is a relatively new device for assessing neuropathy by measuring current perception threshold (CPT). The study aim was to assess the ability of the Neurometer to distinguish between different types of nerve fibre damage by using different frequencies (2000 Hz, 250 Hz, and 5 Hz) of electric stimulus (high frequencies for large fibres and low frequencies for small fibres) and comparing the results with standard sensory tests of vibration perception threshold (VPT) and thermal perception threshold (TPT). CPT was determined on index finger and great toe of 51 patients with diabetic neuropathy and 28 non-diabetic control subjects, age and sex matched. CPT in neuropathic patients could be distinguished from controls at all three frequencies in both feet and hands (p < 0.05). The best correlation was found between CPT at 2000 Hz and VPT (r = 0.48, p < 0.001) in the feet suggesting a degree of neuroselectivity. Internal correlations between CPT at the three frequencies showed the weakest correlation between CPT at 2000 Hz and 5 Hz (r = 0.27, p < 0.005), suggesting also that possibly different types of fibres were examined. CPT reproducibility was better in control (CV = 6.4-27.7%), than in neuropathic subjects (CV = 28.4-52.3%), although the coefficient of variation was comparable to that of standard tests of sensory function, VPT and TPT. The Neurometer is a simple instrument to use in clinical practice. It has a degree of neuroselectivity but like all subjective sensory tests has a large variability.