Cervical Health in Systemic Lupus Erythematosus

Objective

A health disparity exists for African American (AA) women with systemic lupus erythematosus (SLE) who have increased prevalence of human papilloma virus (HPV) infection and cervical neoplasia. We used a self-sampling brush to obtain cervical cells to assess cytology, HPV infection, and vaginal cytokine production in AA women with SLE.

Methods

Thirty AA women with SLE ages 18-50 years consented to participate. Clinical information was obtained by review of records and patient interviews, and surveys administered to assess cervical health history, knowledge of HPV, and satisfaction with the self-sampling brush. Vaginal samples were analyzed for cytology, HPV DNA and RNA, and vaginal cytokine RNA.

Results

Our cohort (mean 36.9, ±9.4 years) had moderate/severe SLE and were on immunosuppressives. The majority had history of abnormal pap smears (63%) with prevalent risk factors for HPV infection: multiple sex partners (9.5 ± 7), not vaccinated for HPV (83.3%), smoking (26.7%), and not using condoms (73.3%). Most were aware of HPV causing cervical cancer (70%) but were unaware of other HPV-related diseases. Most preferred self-sampling over traditional pap smear (80%). Abnormal cytology was detected in 13.3%. HPV DNA was detected in 70%, with half showing multiple types, and all showing active infection (+RNA). HPV-infected samples demonstrated RNA expression of multiple cytokines with no specific/ consistent pattern.

Conclusion

Our high-risk cohort lacked knowledge about HPV-related diseases and were not employing strategies to reduce their risk with vaccination and condoms. This study highlights the need for cervical health education, increased monitoring, and intervention in these high-risk women.

Histopathologic and Cytopathologic Diagnostic Discrepancies in Head and Neck Region: Pitfalls, Causes, and Preventive Strategies

BACKGROUND: Clinicians commonly utilize fine needle aspiration biopsy (FNAB) for the primary investigation of head and neck masses. Correlation of these results with the surgical resection diagnosis is an essential part of quality control and assurance programs in all cytology laboratories.

METHODS: Of 610 cases, 20 (3.3%) had corresponding surgical resections performed within 3 months of the FNAB, with a discrepant diagnosis identified through a search that involved all FNABs performed on the head and neck region, excluding the thyroid gland, at Wayne State University between 1999 and 2004. Sites of discrepant samples included the parotid or submandibular gland (n = 5), lymph nodes (n = 8), and paratracheal/paraesophageal neck masses (n = 7).

RESULTS: The reasons of false-negative FNABs included sampling errors (n = 3), insufficient material for an adequate interpretation (n = 5), lack of triage necessary for ancillary studies (n = 4), and interpretation errors (n = 6). There were 2 false-positive FNABs, both reported as mucoepidermoid carcinoma and showed chronic sialadenitis in one and lymphoepithelial cyst in the other.

CONCLUSIONS: FNAB is an effective tool for the diagnosis and triage of patients with head and neck masses that can be further improved with an onsite immediate adequacy evaluation and triage performed by a pathologist.

Factors predicting nodal metastasis in endometrial cancer

PURPOSE

Evaluation of lymph node (LN) metastases in endometrial carcinoma (EC) is an important prognostic factor and a required element of cancer staging. The purpose of this study is to analyze what factors might predict the likelihood of nodal involvement in EC.

METHODS

A retrospective search of our institutional database for hysterectomies with associated LN dissection in women with EC revealed 207 cases between 2005 and 2012. Cases with primary EC, irrespective of histologic subtype, including carcinosarcomas were included in the study, but pure sarcomas were excluded. We evaluated various factors including tumor size (TS; ≤2.0 cm and >2.0 cm), depth of myometrial invasion (DMI; absent, ≤50 %, >50 %), positive pelvic cytology (PPC), cervical stromal invasion (CSI), and lymph-vascular invasion (LVI), to determine which factors correlated with the presence of LN metastasis.

RESULTS

Of the 207 (age = 62.29 ± 10.9, mean ± SD) cases of EC with LN dissection in our study group, 34 (16.42 %) had positive LNs. On univariate analysis, we found that TS (p = 0.04), tumor grade (Grade I and II versus grade III, p < 0.0001), DMI (p < 0.0001), CSI (p < 0.0001), LVI (p < 0.0001), and PPC (p = 0.001) showed statistically significant correlation with LN metastasis. However, on multivariate analysis, only DMI (p = 0.002) and LVI (p = 0.004) independently showed statistically significant correlation with LN metastasis. In addition, 18 (8.7 %) grade I and II (well/moderately differentiated) tumors with TS ≤2.0 cm and <50 % DMI showed no LN metastasis, LVI, CSI, or PPC.

CONCLUSION

We concluded that DMI and LVI were independent factors predictive of LN metastasis.

Preoperative fine needle aspiration of axillary lymph nodes in breast cancer: clinical utility, diagnostic accuracy and potential pitfalls

OBJECTIVE

This study evaluates the diagnostic accuracy of axillary lymph node fine needle aspiration (FNA) cytology in breast cancer and correlates it with clinical parameters/outcomes.

STUDY DESIGN

A total of 91 females underwent FNA of axillary lymph nodes at our institution from January 2007 to February 2013. The cases were classified as 'positive', 'negative for malignancy' and 'nondiagnostic'.

RESULTS

Forty-six cases (50.5%) had a histologic follow-up (4.4 ± 3.1 months); of these, 22 (47.8%) were true positive, 7 (15.2%) were true negative, 2 (4.3%) were false negative, 5 (11%) were false positive and 10 (21.7%) were nondiagnostic. However, cytological review of all false positive and false negative cases confirmed the presence or absence of tumor, respectively. All false positive cases had undergone preoperative neoadjuvant chemotherapy, with no residual tumor present, and a treatment effect identified only histologically. Meanwhile, the 2 false negative cases involved micrometastasis (≤ 1.5 mm). Thus, if we exclude these false positive cases (complete responders), then the sensitivity, specificity, positive predictive value and negative predictive value were 91.7, 100, 100 and 77.8%, respectively. All preoperative FNA-positive axillary lymph nodes were spared from sentinel lymph node biopsy except for 3 of 27 (11.1%).

CONCLUSION

We suggest that axillary lymph node FNA is a highly sensitive technique with a low false negative rate (4.3%) and a diagnostic accuracy of 93.5%.

Metastatic renal cell carcinoma to the pancreas: diagnostic significance of fine-needle aspiration cytology

BACKGROUND

Renal cell carcinoma rarely metastasizes to the pancreas. Diagnosing a neoplasm that is metastatic to the pancreas by fine-needle aspiration (FNA) cytology is often challenging. A detailed clinical history may prove to be beneficial.

CASE REPORTS

A total of 729 pancreatic FNAs were performed from January 2005 through August 2012 at our institution. Among these, we found 3 patients with a prior history of a malignant renal neoplasm who presented with a pancreatic mass: 2 in the tail and 1 in the head. Radiographically, they ranged in size from 2.5 to 7.0 cm. Microscopic evaluation of cytologic material obtained during endoscopic ultrasound-guided FNA (EUS-FNA) revealed cohesive clusters of atypical cells with clear cytoplasm and prominent nucleoli surrounded by a thin capillary network. The neoplastic cells were immunoreactive with CD10 (cases 2 and 3). A diagnosis of metastatic clear cell renal cell carcinoma was rendered for each case based on the morphologic features and immunohistochemical staining pattern of the neoplastic cells. Histologic comparison with the available slides of the corresponding primary renal neoplasm confirmed the diagnosis.

CONCLUSION

We conclude that EUS-FNA of pancreatic masses is an important, effective, and accurate diagnostic modality for early diagnosis of both primary and metastatic neoplasms of the pancreas.

High-grade primary peritoneal serous papillary carcinoma with a wide differential diagnosis: a diagnostic challenge

Serous surface papillary carcinoma of the peritoneum is a rare malignant epithelial tumour that is histologically indistinguishable from high-grade serous papillary carcinoma of ovarian origin. We herein report a case of 66-year-old female with a history of breast carcinoma who presented with abdominal distension and shortness of breath. Imaging studies at the time of initial workup revealed multiple masses in abdominal cavity, and suspicion was high for metastatic carcinoma. The patient underwent exploratory laparotomy with total abdominal hysterectomy and bilateral salpingo-oophorectomy, partial colectomy, and omentectomy. Gross inspection of the omentum showed diffuse tumour caking, and frozen section evaluation of the omental nodules revealed adenocarcinoma with papillary features. Histological examination showed a high-grade papillary carcinoma with numerous psammoma bodies predominantly present within the omentum and peritoneum. Eventually, this case was determined to be a high-grade primary peritoneal serous papillary carcinoma involving the omentum, colon, and appendix, as well as the surfaces of the uterus, bilateral ovaries, and bilateral fallopian tubes. Knowledge of the primary organ of origin in cases of advanced papillary serous carcinomas is essential for both prognosis and staging, as well as for initiation of appropriate treatment. Close post-therapy follow up is required.

Ovarian malignant mixed mullerian tumor with primitive neuroectodermal differentiation: case report with review of the literature

Ovarian malignant mixed mullarian tumor (OMMMT) is a rare and aggressive tumor of the female genital tract, occurring mainly in elderly women. Stage of disease is the most important predictor for survival with no prognostic effect, yet, of heterologous elements. Rare case reports described the peculiar presence of primitive neuroectodermal tissue among other heterologous elements in these tumors. Attractive designations, such as teratoid carcinosarcoma, were set by some authors to describe this subset of lesions, where it was considered a primary neuroectodermal tumor capable of multilineage differentiation. We here report a case of OMMMT in an elderly woman with focal primitive neuroectodermal differentiation as the sole heterologous element, and review the controversy on this topic in the literature.

Pancreatic solid-pseudopapillary neoplasm: report of a case in an elderly man with cytologic-histologic correlation

BACKGROUND

Solid-pseudopapillary neoplasms of the pancreas are rare and unusual tumors, occurring mostly in young women. Their cytologicfeatures are well described in textbooks; however, published reports still show some cytologic findings overlapping with pancreatic endocrine neoplasms and demonstrate the important diagnostic role of endoscopic ultrasound-guided fine needle aspiration.

CASE

A case of solid-pseudopapillary neoplasm of the pancreas occurred in a 61-year-old man; on cytology it was initially diagnosed as pancreatic endo crine neoplasm. The resection specimen in addition to immunohistochemical stains gave away the diagnosis.

CONCLUSION

Endoscopic ultrasound-guided fine needle aspiration remains a valid, minimally invasive procedure in pancreatic cytology. Tumor cells grouped around fibrovascular cores are the most reproducible cytologic finding in these tumors. Immunostains can play an important role when cell block material is available.

Fast drying of Fine Needle Aspiration slides using a hand held fan: impact on turn around time and staining quality

To analyze the impact of using a hand held fan to speed the air-drying process during immediate adequacy evaluation of Fine Needle Aspirations. The effect on turn around time and staining quality is evaluated. Two mirror image air-dried smears for each pass were prepared. One was subjected to a small hand-held fan with a fan diameter of 7 cm held an average distance of 3 to 5 cm from the slide. The other smear was left to dry without a fan. A total of 93 consecutive pairs were evaluated over a 2-month duration. The average time needed for air-drying using the fan was 73 seconds (range 10-300 seconds, standard error 6.986), while it was 200 seconds (range 15-645 seconds, standard error 17.799) for those without fan. This difference was statistically significant (p < 0.001). Smears were then evaluated for single cells, cell clusters and background material and no appreciable difference in stain quality was noted between the 2 groups. The use of a small hand-held fan for air-drying shortened the drying time for FNA adequacy by an average of 127 seconds (63% time reduction) for each pass. The quality of staining was comparable. Using a fan is highly recommended.

[Cutaneous lupus profundus]

The objective of this studies is to review clinical and laboratory features of lupus panniculitis. The authors report 3 cases of lupus profundus from a group of 70 lupus erythematosus. In both cases the lupus panniculitis presented as subcutaneous infiltrated and indurated nodules. The diagnosis was confirmed on clinical, histological and therapeutic data. The evolution is slow and is characterised by regression of the inflammatory lesions with treatment by antimalarial drugs. The lupus panniculitis has generally a favorable prognosis.

Early oxidative stress in the diabetic kidney: effect of DL-alpha-lipoic acid

Oxidative stress is implicated in the pathogenesis of diabetic nephropathy. The attempts to identify early markers of diabetes-induced renal oxidative injury resulted in contradictory findings. We characterized early oxidative stress in renal cortex of diabetic rats, and evaluated whether it can be prevented by the potent antioxidant, DL-alpha-lipoic acid. The experiments were performed on control rats and streptozotocin-diabetic rats treated with/without DL-alpha-lipoic acid (100 mg/kg i.p., for 3 weeks from induction of diabetes). Malondialdehyde plus 4-hydroxyalkenal concentration was increased in diabetic rats vs. controls (p <.01) and this increase was partially prevented by DL-alpha-lipoic acid. F(2) isoprostane concentrations (measured by GCMS) expressed per either mg protein or arachidonic acid content were not different in control and diabetic rats but were decreased several-fold with DL-alpha-lipoic acid treatment. Both GSH and ascorbate (AA) levels were decreased and GSSG/GSH and dehydroascorbate/AA ratios increased in diabetic rats vs. controls (p <.01 for all comparisons), and these changes were completely or partially (AA) prevented by DL-alpha-lipoic acid. Superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione transferase, and NADH oxidase, but not catalase, were upregulated in diabetic rats vs. controls, and these activities, except glutathione peroxidase, were decreased by DL-alpha-lipoic acid. In conclusion, enhanced oxidative stress is present in rat renal cortex in early diabetes, and is prevented by DL-alpha-lipoic acid.

An aldose reductase inhibitor reverses early diabetes-induced changes in peripheral nerve function, metabolism, and antioxidative defense

Aldose reductase inhibitors (ARIs) prevent peripheral nerve dysfunction and morphological abnormalities in diabetic animal models. However, some experimental intervention studies and clinical trials of ARIs on diabetic neuropathy appeared disappointing because of either 1) their inadequate design and, in particular, insufficient correction of the sorbitol pathway activity or 2) the inability to reverse established functional and metabolic deficits of diabetic neuropathy by AR inhibition in general. We evaluated whether diabetes-induced changes in nerve function, metabolism, and antioxidative defense are corrected by the dose of ARI (sorbinil, 65 mg/kg/d in the diet), resulting in complete inhibition of increased sorbitol pathway activity. The groups included control rats and streptozotocin-diabetic rats treated with/without ARI for 2 weeks after 4 weeks of untreated diabetes. ARI treatment corrected diabetes-induced nerve functional changes; that is, decrease in endoneurial nutritive blood flow, motor and sensory nerve conduction velocities, and metabolic abnormalities (i.e., mitochondrial and cytosolic NAD+/NADH redox imbalances and energy deficiency). ARI restored nerve concentrations of two major non-enzymatic antioxidants, reduced glutathione (GSH) and ascorbate, and completely arrested diabetes-induced lipid peroxidation. In conclusion, treatment with adequate doses of ARIs (that is, doses that completely inhibit increased sorbitol pathway activity) is an effective approach for reversal of, at least, early diabetic neuropathy.

Taurine counteracts oxidative stress and nerve growth factor deficit in early experimental diabetic neuropathy

Oxidative stress has a key role in the pathogenesis of diabetic complications. We have previously reported that taurine (T), which is known to counteract oxidative stress in tissues (lens, kidney, retina) of diabetic rats, attenuates nerve blood flow and conduction deficits in early experimental diabetic neuropathy (EDN). The purpose of this study was to evaluate whether dietary T supplementation counteracts oxidative stress and the nerve growth factor (NGF) deficit in the diabetic peripheral nerve. The experiments were performed in control rats and streptozotocin-diabetic rats fed standard or 1% T-supplemented diets for 6 weeks. All measurements were performed in the sciatic nerve. Malondialdehyde (MDA) plus 4-hydroxyalkenals (4-HA) were quantified with N-methyl-2-phenylindole. GSH, GSSG, dehydroascorbate (DHAA), and ascorbate (AA) were assayed spectrofluorometrically, T by reverse-phase HPLC, and NGF by ELISA. MDA plus 4-HA concentration (mean +/- SEM) was increased in diabetic rats (0.127 +/- 0.006 vs 0.053 +/- 0.003 micromol/g in controls, P < 0.01), and this increase was partially prevented by T (0.096 +/- 0.004, P < 0.01 vs untreated diabetic group). GSH levels were similarly decreased in diabetic rats treated with or without taurine vs controls. GSSG levels were similar in control and diabetic rats but were lower in diabetic rats treated with T (P < 0.05 vs controls). AA levels were decreased in diabetic rats (0.133 +/- 0.015 vs 0.219 +/- 0.023 micromol/g in controls, P < 0.05), and this deficit was prevented by T. DHAA/AA ratio was increased in diabetic rats vs controls (P < 0.05), and this increase was prevented by T. T levels were decreased in diabetic rats (2.7 +/- 0.16 vs 3.8 +/- 0.1 micromol/g in controls, P < 0.05) and were repleted by T supplementation (4.2 +/- 0.3). NGF levels were decreased in diabetic rats (2.35 +/- 0.20 vs 3.57 +/- 0.20 ng/g in controls, P < 0.01), and this decrease was attenuated by T treatment (3.16 +/- 0.28, P < 0.05 vs diabetic group). In conclusion, T counteracts oxidative stress and the NGF deficit in early EDN. Antioxidant effects of T in peripheral nerve are, at least in part, mediated through the ascorbate system of antioxidative defense. The findings are consistent with the important role for oxidative stress in impaired neurotrophic support in EDN.

Antioxidants attenuate early up regulation of retinal vascular endothelial growth factor in streptozotocin-diabetic rats

AIMS/HYPOTHESIS

A strong positive correlation has been found between lipid peroxidation product and vascular endothelial growth factor concentrations in the vitreous of patients with proliferative diabetic retinopathy. To establish a causal relation between diabetes-associated enhanced oxidative stress and vascular endothelial growth factor production, we evaluated two antioxidants, DL-alpha-lipoic acid and taurine, on retinal vascular endothelial growth factor protein and mRNA expression and on parameters of oxidative stress in streptozotocin-diabetic rats.

METHODS

Our experiments were on control rats and streptozotocin-diabetic rats with a 6-week duration of diabetes, treated with or without DL-alpha-lipoic acid (100 mg x kg(-1) x d(-1), i.p.) or taurine (1% in the diet) starting from induction of diabetes. Vascular endothelial growth factor protein in retinal homogenates was assessed by sandwich ELISA with an affinity-purified polyclonal antibody and vascular endothelial growth factor mRNA by ribonuclease protection assay. Retinal lipid peroxidation products i.e. malondialdehyde plus 4-hydroxyalkenals were quantified with N-methyl-2-phenylindole. Retinal reduced and oxidized glutathione, ascorbate, dehydroascorbate, and sorbitol pathway intermediates were measured spectrofluorometrically, and taurine by reverse-phase HPLC.

RESULTS

Vascular endothelial growth factor protein concentration (means +/- SD) was increased in diabetic rats compared with control rats (33+/-7 vs 19+/-5 pg/mg total protein, p < 0.01) This increase was attenuated by taurine (26+/-8, p < 0.05) and prevented by DL-alpha-lipoic acid (21+/-4, p < 0.01). Vascular endothelial growth factor mRNA abundance was reduced by 1.4-fold in diabetic rats compared with control rats and this decrease was attenuated but not completely prevented by both antioxidants. Malondialdehyde plus 4-hydroxyalkenal concentration was increased in diabetic rats compared with control rats, and both antioxidants arrested accumulation of lipid peroxidation products. Taurine, reduced glutathione, oxidized glutathione, ascorbate, dehydroascorbate and sorbitol pathway intermediate concentrations as well as oxidized glutathione/reduced glutathione and dehydroascorbate/ascorbate ratios were similar in control and diabetic rats treated with or without taurine.

CONCLUSION/INTERPRETATION

Oxidative stress is directly involved in up regulation of vascular endothelial growth factor protein in the retina during early diabetes.

Evaluation of an aldose reductase inhibitor on lens metabolism, ATPases and antioxidative defense in streptozotocin-diabetic rats: an intervention study

AIMS/HYPOTHESIS

Aldose reductase inhibitors (ARIs) prevent biochemical abnormalities associated with diabetic complications. We evaluated whether a short-term intervention with an adequate dose of ARI, introduced at the very early, precataractous stage, reversed diabetes-induced metabolic imbalances, down-regulation of ATPases and oxidative stress in the lens. Methods. The groups included mature control and streptozotocin-diabetic rats treated with or without ARI sorbinil (65 mg x kg(-1) x day(-1), in the diet, for 2 weeks after 4 weeks of untreated diabetes). Free cytosolic NAD+:NADH and NADP+:NADPH ratios were calculated from the lactate dehydrogenase and malic enzyme systems. Concentrations of metabolites and adenine nucleotides, Na+/K+-ATPase, H+-ATPase and Ca++-independent Mg++-ATPase activities and variables of oxidative stress were measured in individual lenses. Results. Sorbinil treatment essentially corrected diabetes-induced sorbitol and fructose accumulation, myo-inositol depletion, decrease in free cytosolic NAD+:NADH ratio and energy deficiency. Malondialdehyde accumulation, reduced glutathione depletion and the increase in oxidized glutathione:reduced glutathione ratio were partially corrected. Free cytosolic NADP+:NADPH ratio and 4-hydroxyalkenal concentrations were similarly increased in diabetic rats treated with or without ARI. Sorbinil did not counteract diabetes-induced down-regulation of the three ATPase activities.

CONCLUSION/INTERPRETATION

All biochemical changes assessed in our study are known to be prevented by ARIs. Despite the essential normalization of the sorbitol pathway activity, only part of them were, however, reversed by the ARI treatment introduced at the very early, i.e. precataractous, stage of diabetes. Therefore, intervention studies can easily underestimate the importance of aldose reductase in the pathogenesis of diabetic complications and should be interpreted with caution.

Evaluation of alpha(1)-adrenoceptor antagonist on diabetes-induced changes in peripheral nerve function, metabolism, and antioxidative defense

The role for nerve blood flow (NBF) vs. other factors in motor nerve conduction (MNC) slowing in short-term diabetes was assessed by evaluating alpha(1)-adrenoceptor antagonist prazosin on NBF, MNC, as well as metabolic imbalances and oxidative stress in the neural tissue. Control and diabetic rats were treated with or without prazosin (5 mg.kg(-1).d(-1) for 3 wk). NBF was measured by hydrogen clearance. Both endoneurial vascular conductance and MNC velocity were decreased in diabetic rats vs. controls, and this decrease was prevented by prazosin. Free NAD(+):NADH ratios in mitochondrial cristae, matrix, and cytosol assessed by metabolite indicator method, as well as phosphocreatine levels and phosphocreatine/creatine ratios, were decreased in diabetic rats, and this reduction was ameliorated by prazosin. Neither diabetes-induced accumulation of two major glycation agents, glucose and fructose, as well as sorbitol and total malondialdehyde plus 4-hydroxyalkenals nor depletion of myo-inositol, GSH, and taurine or decrease in (Na/K)-ATP-ase activity were affected by prazosin. In conclusion, decreased NBF, but not metabolic imbalances or oxidative stress in the neural tissue, is a key mechanism of MNC slowing in short-term diabetes. Further experiments are needed to estimate whether preservation of NBF is sufficient for prevention of nerve dysfunction and morphological abnormalities in long-standing diabetes or whether the aforementioned metabolic imbalances closely associated with impaired neurotropism are of greater importance in advanced than in early diabetic neuropathy.

Early changes in lipid peroxidation and antioxidative defense in diabetic rat retina: effect of DL-alpha-lipoic acid

This study was designed to (1) evaluate retinal lipid peroxidation in early diabetes by the method specific for free malondialdehyde and 4-hydroxyalkenals, (2) identify impaired antioxidative defense mechanisms and (3) assess if enhanced retinal oxidative stress in diabetes is prevented by the potent antioxidant, DL-alpha-lipoic acid. The groups included control and streptozotocin-diabetic rats treated with or without DL-alpha-lipoic acid (100 mg kg(-1) day(-1), i.p., for 6 weeks). All parameters were measured in individual retinae. 4-Hydroxyalkenal concentration was increased in diabetic rats (2.63+/-0.60 vs. 1.44+/-0.30 nmol/mg soluble protein in controls, P<0.01), and this increase was prevented by DL-alpha-lipoic acid (1.20+/-0.88, P<0.01 vs. untreated diabetic group). Malondialdehyde, reduced glutathione (GSH) and oxidized glutathione (GSSG) concentrations were similar among the groups. Superoxide dismutase, glutathione peroxidase (GSHPx), glutathione reductase (GSSGRed) and glutathione transferase (GSHTrans) activities were decreased in diabetic rats vs. controls. Quinone reductase was upregulated in diabetic rats, whereas catalase and cytoplasmic NADH oxidase activities were unchanged. DL-alpha-Lipoic acid prevented changes in superoxide dismutase and quinone reductase activities induced by diabetes without affecting the enzymes of glutathione metabolism. In conclusion, accumulation of 4-hydroxyalkenals is an early marker of oxidative stress in the diabetic retina. Increased lipid peroxidation occurs in the absence of GSH depletion, and is prevented by DL-alpha-lipoic acid.

Interaction between osmotic and oxidative stress in diabetic precataractous lens: studies with a sorbitol dehydrogenase inhibitor

Both sorbitol accumulation-linked osmotic stress and "pseudohypoxia" [increase in NADH/NAD+, similar to that in hypoxic tissues, and attributed to increased sorbitol dehydrogenase (1-iditol:NAD+ 5-oxidoreductase; EC 1.1.1.14; SDH) activity] have been invoked among the mechanisms underlying oxidative injury in target tissues for diabetic complications. We used the specific SDH inhibitor SDI-157 [2-methyl-4(4-N,N-dimethylaminosulfonyl-1-piperazino)pyrimid ine] to evaluate the role of osmotic stress versus "pseudohypoxia" in oxidative stress occurring in diabetic precataractous lens. Control and diabetic rats were treated with or without SDI-157 (100 mg/kg/day for 3 weeks). Lens malondialdehyde (MDA) plus 4-hydroxyalkenals (4-HA), MDA, GSH, and ascorbate levels, as well as the GSSG/GSH ratios, were similar in SDI-treated and untreated control rats, thus indicating that SDI-157 was not a prooxidant. Intralenticular osmotic stress, manifested by sorbitol levels, was more severe in SDI-treated diabetic rats (38.2+/-6.8 vs 21.2+/-3.5 micromol/g in untreated diabetic and 0.758+/-0.222 micromol/g in control rats, P<0.01 for both), while the decrease in the free cytosolic NAD+/NADH ratio was partially prevented (120+/-16 vs 88+/-11 in untreated diabetic rats and 143+/-13 in controls, P<0.01 for both). GSH and ascorbate levels were decreased, while MDA plus 4-HA and MDA levels were increased in diabetic rats versus controls; both antioxidant depletion and lipid aldehyde accumulation were exacerbated by SDI treatment. Superoxide dismutase (superoxide:superoxide oxidoreductase; EC 1.15.1.1), GSSG reductase (NAD[P]H:oxidized-glutathione oxidoreductase; EC 1.6.4.2), GSH transferase (glutathione S-transferase; EC 2.5.1.18), GSH peroxidase (glutathione:hydrogen-peroxide oxidoreductase; EC 1.11.1.9), and cytoplasmic NADH oxidase activities were increased in diabetic rats versus controls, and all the enzymes but GSH peroxidase were up-regulated further by SDI. In conclusion, sorbitol accumulation and osmotic stress generated oxidative stress in diabetic lens, whereas the contribution of "pseudohypoxia" was minor. SDIs provide a valuable tool for exploring mechanisms of oxidative injury in sites of diabetic complications.

Evaluation of a sorbitol dehydrogenase inhibitor on diabetic peripheral nerve metabolism: a prevention study

AIMS/HYPOTHESIS

Studies of the role of sorbitol dehydrogenase in nerve functional deficits induced by diabetes reported contradictory results. We evaluated whether sorbitol dehydrogenase inhibition reduces metabolic abnormalities and enhances oxidative stress characteristic of experimental diabetic neuropathy.

METHODS

Control and streptozotocin-diabetic rats were treated with or without sorbitol dehydrogenase inhibitor (SDI)-157 (100 mg x kg(-1) x day(-1), in the drinking water, for 3 weeks). Sciatic nerve free mitochondrial (cristae and matrix) and cytosolic NAD(+): NADH ratios were calculated from the beta-hydroxybutyrate, glutamate and lactate dehydrogenase systems. Concentrations of metabolites, e. g. sorbitol pathway intermediates and variables of energy state were measured in individual nerves spectrofluorometrically by enzymatic procedures.

RESULTS

The flux through sorbitol dehydrogenase (manifested by nerve fructose concentrations) was inhibited by 53 % and 74 % in control and diabetic rats treated with SDI compared with untreated control and diabetic groups. Free NAD(+):NADH ratios in mitochondrial cristae, matrix and cytosol were decreased in diabetic rats compared with controls and reduction in either of the three variables was not prevented by sorbitol dehydrogenase inhibitor. Phosphocreatine concentrations and phosphocreatine:creatine ratios were decreased in diabetic rats compared with controls and were further reduced by the inhibitor. Malondialdehyde plus 4-hydroxyalkenals concentration was increased and reduced gluthathione concentration was reduced in diabetic rats compared with the control group, and changes in both variables were further exacerbated by sorbitol dehydrogenase inhibitor. Neither NAD-redox and energy states nor lipid aldehyde and reduced gluthathione concentrations were affected by treatment with the inhibitor in control rats.

CONCLUSION/INTERPRETATION

Inhibition of sorbitol dehydrogenase does not offer an effective approach for prevention of oxidation and metabolic imbalances in the peripheral nerve that is induced by diabetes and is adverse rather than beneficial. [Diabetologia (1999) 42: 1187-1194]